U.S. patent application number 17/256998 was filed with the patent office on 2021-05-13 for nuclear fuel assembly manufacturing method, nuclear fuel assembly manufacturing plant and method of expanding such a plant.
The applicant listed for this patent is FRAMATOME. Invention is credited to Andreas FALGE, Amaury FAYARD, Lawrence MERCIER.
Application Number | 20210142918 17/256998 |
Document ID | / |
Family ID | 1000005359725 |
Filed Date | 2021-05-13 |
![](/patent/app/20210142918/US20210142918A1-20210513\US20210142918A1-2021051)
United States Patent
Application |
20210142918 |
Kind Code |
A1 |
MERCIER; Lawrence ; et
al. |
May 13, 2021 |
NUCLEAR FUEL ASSEMBLY MANUFACTURING METHOD, NUCLEAR FUEL ASSEMBLY
MANUFACTURING PLANT AND METHOD OF EXPANDING SUCH A PLANT
Abstract
A method is for manufacturing a nuclear fuel assembly (2)
comprising nuclear fuel rods (4) arranged in a bundle and a
skeleton (6) supporting the fuel rods (4). The method comprise the
steps of inserting fuel rods (4) into the skeleton (6) to obtain a
fuel assembly (2) and packaging the fuel assembly (2) in view of
transportation. The steps are being performed in a same nuclear
fuel assembly manufacturing plant (20), preferably in a same
nuclear fuel assembly manufacturing building (60).
Inventors: |
MERCIER; Lawrence; (ROMANS
SUR IS RE, FR) ; FALGE; Andreas; (NORDHORN, DE)
; FAYARD; Amaury; (LINGEN, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FRAMATOME |
COURBRVOIE |
|
FR |
|
|
Family ID: |
1000005359725 |
Appl. No.: |
17/256998 |
Filed: |
July 4, 2019 |
PCT Filed: |
July 4, 2019 |
PCT NO: |
PCT/IB2019/055721 |
371 Date: |
December 29, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G21C 3/334 20130101;
G21C 3/3424 20130101; G21C 17/06 20130101; G21C 3/3315 20130101;
G21C 21/02 20130101 |
International
Class: |
G21C 3/334 20060101
G21C003/334; G21C 21/02 20060101 G21C021/02; G21C 3/33 20060101
G21C003/33; G21C 3/34 20060101 G21C003/34; G21C 17/06 20060101
G21C017/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 5, 2018 |
IB |
PCT/IB2018/001153 |
Claims
1 to 30. (canceled)
31. A method for manufacturing a nuclear fuel assembly comprising
nuclear fuel rods arranged in a bundle and a skeleton supporting
the fuel rods, the method comprising: steps of inserting fuel rods
into the skeleton to obtain a nuclear fuel assembly and packaging
the nuclear fuel assembly in view of transportation, the inserting
and packaging steps being performed in a same nuclear fuel assembly
manufacturing plant; and a step of receiving fuel rods transported
from a nuclear fuel rod manufacturing plant separated by a
non-confined area from the nuclear fuel assembly manufacturing
plant, wherein these fuel rods are used during the inserting
step.
32. The method according to claim 31, wherein the fuel rods are
received packaged in at least a fuel assembly container, the method
comprising using the fuel assembly container for packaging the
nuclear fuel assembly obtained by performing the inserting
step.
33. The method according to claim 31, further comprising receiving
nuclear fuel pellets transported from a nuclear fuel pellet
manufacturing plant separated by a non-confined area from the
nuclear fuel assembly manufacturing plant, wherein these nuclear
fuel pellets are used during a fuel rod manufacturing step.
34. The method according to claim 33, wherein the fuel rod
manufacturing step comprises placing the nuclear fuel pellets on
pellet trays, inserting the pellet trays in an outgassing furnace
for removing potential hydrogenous contamination from the nuclear
fuel pellets, loading the nuclear fuel pellets from the pellet
trays into a cladding tube in a fuel rod loading station, inserting
a spring into the cladding tube, filling the cladding tube with
helium gas and/or welding plugs at the ends of the cladding tubes
for closing the fuel rod.
35. The method according to claim 34, wherein the step of welding
the plugs of each fuel rod is performed with using a single welding
station, with presenting a first end of the cladding tube to the
welding station, welding a first plug to the first end, presenting
a second end of the cladding tube to the welding station and
welding a second plug to the second end.
36. The method according to claim 31, further comprising a step of
cleaning the fuel assembly and/or a step of inspecting the fuel
assembly.
37. The method according to claim 36, wherein the cleaning step
and/or the inspecting step is/are performed with positioning the
fuel assembly in a vertical position and/or substantially at ground
level.
38. The method according to claim 36, wherein the method includes
the cleaning step and the cleaning step is performed by air blowing
cleaning and/or high pressure cleaning and/or washing with bubbling
water and/or brushing cleaning.
39. The method according to claim 36, wherein the method includes
the inspecting step and the inspecting step comprises visually
inspecting the fuel assembly positioned vertically using at least
one elevator for ascending and/or descending an operator along the
fuel assembly.
40. A plant configured for manufacturing a nuclear fuel assembly
comprising nuclear fuel rods arranged in a bundle and a skeleton
supporting the fuel rods, the plant comprising: a fuel assembly
manufacturing unit comprising an inserting station configured for
insertion of the nuclear fuel rods into the skeleton to obtain a
fuel assembly; and a packaging station configured for packaging the
fuel assembly into a fuel assembly container in view of
transportation.
41. The plant according to claim 40, wherein the inserting station
and the packaging station are located in a same building, provided
with a crane configured for moving the fuel assembly between the
inserting station and the packaging station.
42. The plant according to claim 40, wherein the fuel assembly
manufacturing unit comprises a cleaning station configured for
cleaning of the fuel assembly and/or a fuel assembly inspection
station configured for inspection of the fuel assembly.
43. The plant according to claim 42, wherein the cleaning station
and/or the fuel assembly inspection station is/are configured for
cleaning and/or inspecting the fuel assembly in a vertical position
and/or substantially at ground level.
44. The plant according to claim 42, wherein the cleaning station
and/or the fuel assembly inspection station comprise(s) a
telescopic enclosure movable between a retracted position for
loading the fuel assembly into the station and an extended position
for enclosing the fuel assembly loaded into the station.
45. The plant according to claim 42, wherein the cleaning station
and/or the fuel assembly inspection station comprise(s) at least
one elevator for moving an operator vertically along the nuclear
fuel assembly positioned vertically.
46. The plant according to claim 40, further comprising a fuel rod
manufacturing unit comprising a pellet receiving area configured
for receiving nuclear fuel pellets, a pellet inspection area
configured for inspection of the nuclear fuel pellets, an
outgassing station comprising at least one outgassing furnace
configured to expel potential hydrogenous contamination of the
nuclear fuel pellets, a cladding station configured to receive
cladding tubes and check the received cladding tubes, a fuel rod
loading station configured for loading the nuclear fuel pellets
into a cladding tube, a welding station configured for welding
plugs to the ends of the cladding tube to form a fuel rod and/or at
least one fuel rod inspection station configured for inspection of
the fuel rod.
47. The plant according to claim 46, comprising the welding station
and the at least one fuel rod inspection station, the plant further
comprising a first conveying system configured for conveying the
fuel rods to the at least one fuel rod inspection station(s), a
second conveying system for conveying the fuel rods from the last
inspection station to the inserting station, the first conveying
system extending along a first direction and the second conveying
system extending in a second direction making a non-zero angle with
the first direction, and a pivoting trolley configured for
transferring the fuel rods from the first conveying system to the
second conveying system with pivoting the fuel rods.
48. The plant according to claim 46, wherein the plant is housed in
a building made of building modules, the fuel assembly
manufacturing unit being housed in one or several building
module(s) and the fuel rod manufacturing unit being housed in one
of several building module(s) distinct from the building module(s)
housing the fuel assembly manufacturing unit.
49. The plant according to claim 40, further comprising a logistic
area configured for shipping the fuel assemblies manufactured in
the plant, for receiving skeleton parts to be assembled to obtain
the skeletons and/or for receiving fuel rods.
50. The plant according to claim 40, wherein the fuel assembly
manufacturing unit is configured for interconnection with another
manufacturing unit to be installed side-by-side with the fuel
assembly manufacturing unit.
51. The plant according to claim 50, wherein the fuel assembly
manufacturing unit comprises at least one utility system configured
for interconnection with a corresponding utility system of said
other manufacturing unit connected with the fuel assembly
manufacturing unit.
52. The plant according to claim 50, wherein the fuel assembly
manufacturing unit comprises at least one utility system configured
to operate independently from a corresponding utility system of
another manufacturing unit connected with the fuel assembly
manufacturing unit.
53. The plant according to claim 50, wherein said other
manufacturing unit is another fuel assembly manufacturing unit for
increasing manufacturing capacity or a fuel rod manufacturing unit
configured for manufacturing fuel rods starting from nuclear fuel
pellets.
54. A method of expanding a plant for manufacturing a nuclear fuel
assembly comprising nuclear fuel rods arranged in a bundle and a
skeleton supporting the fuel rods, the plant having a fuel assembly
manufacturing unit comprising an inserting station configured for
insertion of fuel rods into the skeleton to obtain the fuel
assembly and a packaging station configured for packaging the fuel
assembly into a fuel assembly container in view of transportation,
method comprising: a step of building at least one additional
manufacturing unit and connecting the additional manufacturing unit
to the fuel assembly manufacturing unit.
55. The method according to claim 54, wherein the additional
manufacturing unit is a fuel rod manufacturing unit configured for
manufacturing nuclear fuel rods starting from nuclear fuel
pellets.
56. The method according to claim 55, further comprising a step of
building a fuel pellet manufacturing unit configured for
manufacturing UO.sub.2 based nuclear fuel pellets and connecting
the fuel pellet manufacturing unit to the fuel rod manufacturing
unit.
57. The method according to claim 56, further comprising a step of
building a fuel powder manufacturing unit configured for converting
UF.sub.6 into UO.sub.2 and connecting the fuel powder manufacturing
unit to the fuel pellet manufacturing unit.
58. The method according to claim 54, further comprising building
an additional manufacturing unit which is another fuel assembly
manufacturing unit for increasing manufacturing capacity.
59. The method according to claim 58, further comprising a step of
building an additional fuel pellet manufacturing unit configured
for manufacturing UO.sub.2 based nuclear fuel pellets and
connecting the additional fuel pellet manufacturing unit to the
additional fuel rod manufacturing unit.
60. The method according to claim 59, further comprising a step of
building an additional fuel powder manufacturing unit configured
for converting UF.sub.6 into UO.sub.2 and connecting the additional
fuel powder manufacturing unit to the additional fuel pellet
manufacturing unit.
Description
[0001] The present disclosure relates to the technical field of
manufacturing nuclear fuel assemblies.
BACKGROUND
[0002] A nuclear fuel assembly (or "fuel assembly") comprises
nuclear fuel rods (or "fuel rods") arranged in a bundle and a
skeleton supporting the fuel rods.
[0003] Each fuel rod comprises a tubular cladding containing
nuclear fuel pellets (e.g. UO.sub.2 pellets), the two ends of the
tubular cladding being closed by respective end plugs. Generally, a
fuel rod spring is inserted in the fuel rod cladding for exerting a
compression force on the pellets to avoid movement of the pellets
inside the fuel rod. The pellets are for example obtained by
compaction of nuclear fuel powder (e.g. UO.sub.2 powder).
[0004] The skeleton comprises for example a bottom nozzle and an
top nozzle spaced along a longitudinal axis, guide thimbles
extending along the longitudinal axis between the bottom nozzle and
the top nozzle with connecting the bottom nozzle and the top nozzle
together, and spacer grids attached to the guide thimbles with
being distributed along the guide thimbles. The fuel rods extend
through the spacer grids and between the bottom nozzle and the top
nozzle. The function of the spacer grids is to support the fuel
rods.
[0005] Manufacturing fuel assemblies requires producing the nuclear
fuel powder, pelletizing the nuclear fuel powder to obtain the
nuclear fuel pellets (or "pellets"), producing fuel rods namely by
loading the pellets into the cladding tubes and welding plugs at
the ends of the cladding tubes, manufacturing the skeleton and
inserting the fuel rods into the skeleton.
[0006] The thus manufactured fuel assemblies can be packaged for
transportation to nuclear power plants.
[0007] Today, these operations are performed in a same nuclear fuel
assembly manufacturing plant.
[0008] Besides, manual production is generally replaced
progressively by automation to improve productivity, increase
capacity and manage a more continuous flow of operations.
[0009] However, it is necessary to provide protections to the
buildings and to the equipment to comply with risks such as fire,
flooding, seism. Such protections increase when the manufacturing
is automatized.
[0010] This leads to a nuclear fuel assembly manufacturing plant
with a large footprint, the nuclear fuel assembly manufacturing
plant being complex to operate and subject to numerous
regulations.
[0011] Owing to these constrains, it appears difficult to construct
new nuclear fuel assembly manufacturing plants, leading to
difficulties of procurement for the nuclear power plant
operators.
SUMMARY
[0012] One of the aims of the present disclosure is to propose a
nuclear fuel assembly manufacturing method that allows constructing
and operating a nuclear fuel assembly manufacturing plant more
easily.
[0013] To this end, a method is provided for manufacturing a
nuclear fuel assembly comprising nuclear fuel rods arranged in a
bundle and a skeleton supporting the fuel rods, the method
comprising the steps of inserting fuel rods into the skeleton to
obtain a fuel assembly and packaging the fuel assembly in view of
transportation, the steps being performed in a same nuclear fuel
assembly manufacturing plant, preferably in a same nuclear fuel
assembly manufacturing building.
[0014] In specific embodiments, the method comprises one or several
of the following features: [0015] a step of receiving fuel rods
transported from a nuclear fuel rod manufacturing plant separated
by a non-confined area from the nuclear fuel assembly manufacturing
plant, wherein these fuel rods are used during the inserting step;
[0016] the fuel rods are received packaged in at least a fuel
assembly container, the method comprising using the fuel assembly
container for packaging a nuclear fuel assembly obtained by
performing the inserting step; [0017] receiving nuclear fuel
pellets transported from a nuclear fuel pellet manufacturing plant
separated by a non-confined area from the nuclear fuel assembly
manufacturing plant, wherein these pellets are used during a fuel
rod manufacturing step; [0018] the fuel rod manufacturing step
comprises placing the pellets on pellet trays, inserting the pellet
trays in an outgassing furnace for removing potential hydrogenous
contamination from the pellets, loading the pellets from the pellet
trays into a cladding tube in a fuel rod loading station, inserting
a spring into the cladding tube, filling the cladding tube with
helium gas and/or welding plugs at the ends of the cladding tubes
for closing the fuel rod; [0019] the step of welding the plugs of
each fuel rod is performed with using a single welding station,
with presenting a first end of the cladding tube to the welding
station, welding a first plug to the first end, presenting a second
end of the cladding tube to the welding station and welding a
second plug to the second end; [0020] a step of cleaning the fuel
assembly and/or a step of inspecting the fuel assembly; [0021] the
cleaning step and/or the inspecting step is/are performed with
positioning the fuel assembly in a vertical position and/or
substantially at ground level; [0022] the cleaning step is
performed by air blowing cleaning and/or high pressure cleaning
and/or washing with bubbling water and/or brushing cleaning, for
example manual brushing cleaning; [0023] inspecting step comprises
visually inspecting the fuel assembly positioned vertically using
at least one elevator for ascending and/or descending an operator
along the fuel assembly;
[0024] The present disclosure also relates to a plant configured
for manufacturing a nuclear fuel assembly comprising nuclear fuel
rods arranged in a bundle and a skeleton supporting the fuel rods,
the plant comprising a fuel assembly manufacturing unit comprising
an inserting station configured for insertion of the fuel rods into
the skeleton to obtain the fuel assembly and a packaging station
configured for packaging the fuel assembly into a fuel assembly
container in view of transportation.
[0025] In specific embodiments, the plant comprises one or several
of the following features: [0026] the inserting station and the
packaging station are located in a same building, preferably in a
same assembling hall, provided with a crane configured for moving
the fuel assembly between the inserting station and the packaging
station; [0027] the fuel assembly manufacturing unit comprises a
cleaning station configured for cleaning of the fuel assembly
and/or a fuel assembly inspection station configured for inspection
of the fuel assembly; [0028] the cleaning station and/or the fuel
assembly inspection station is/are configured for cleaning and/or
inspecting the fuel assembly in a vertical position and/or
substantially at ground level; [0029] the cleaning station and/or
the fuel assembly inspection station comprise(s) a telescopic
enclosure movable between a retracted position for loading the fuel
assembly into the station and an extended position for enclosing
the fuel assembly loaded into the station; [0030] the cleaning
station and/or the fuel assembly inspection station comprise(s) at
least one elevator for moving an operator vertically along the
nuclear fuel assembly positioned vertically, e.g. for performing a
visual inspection; [0031] a fuel rod manufacturing unit comprising
a pellet receiving area configured for receiving nuclear fuel
pellets, a pellet inspection area configured for inspection of the
pellets, an outgassing station comprising at least one outgassing
furnace configured to expel potential hydrogenous contamination of
the pellets, a cladding station configured to receive cladding
tubes and check the received cladding tubes, a fuel rod loading
station configured for loading the pellets into a cladding tube, a
welding station configured for welding plugs to the ends of the
cladding tube to form a fuel rod and/or at least one fuel rod
inspection station configured for inspection of the fuel rod;
[0032] it comprises the welding station and the at least one fuel
rod inspection station, the plant further comprising a first
conveying system configured for conveying the fuel rods to the at
least one fuel rod inspection station(s), a second conveying system
for conveying the fuel rods from the last inspection station to the
inserting station, the first conveying system extending along a
first direction and the second conveying system extending in a
second direction making a non-zero angle with the first direction,
and a pivoting trolley configured for transferring the fuel rods
from the first conveying system to the second conveying system with
pivoting the fuel rods; [0033] it comprises a logistic area
configured for shipping the fuel assemblies manufactured in the
plant, for receiving skeleton parts to be assembled to obtain the
skeletons and/or for receiving fuel rods; [0034] the fuel assembly
manufacturing unit is configured for interconnection with another
manufacturing unit to be installed side-by-side with the fuel
assembly manufacturing unit ; [0035] the fuel assembly
manufacturing unit comprises at least one utility system configured
for interconnection with a corresponding utility system of said
other manufacturing unit connected with the fuel assembly
manufacturing unit; [0036] the fuel assembly manufacturing unit
comprises at least one utility system configured to operate
independently from a corresponding utility system of another
manufacturing unit connected with the fuel assembly manufacturing
unit; [0037] said other manufacturing unit is another fuel assembly
manufacturing unit for increasing manufacturing capacity or a fuel
rod manufacturing unit configured for manufacturing fuel rods
starting from nuclear fuel pellets.
[0038] A method is also provided of expanding a plant for
manufacturing a nuclear fuel assembly comprising nuclear fuel rods
arranged in a bundle and a skeleton supporting the fuel rods, the
plant having a fuel assembly manufacturing unit comprising an
inserting station configured for insertion of fuel rods into the
skeleton to obtain the fuel assembly and a packaging station
configured for packaging the fuel assembly into a fuel assembly
container in view of transportation, wherein said method includes a
step of building at least one additional manufacturing unit and
connecting the additional manufacturing unit to the fuel assembly
manufacturing unit.
[0039] In specific embodiments, the method may comprise one or
several of the following optional features: [0040] the additional
manufacturing unit is a fuel rod manufacturing unit configured for
manufacturing nuclear fuel rods starting from nuclear fuel pellets;
[0041] said method includes a step of building a fuel pellet
manufacturing unit configured for manufacturing UO.sub.2 based
nuclear fuel pellets and connecting the fuel pellet manufacturing
unit to the fuel rod manufacturing unit; [0042] said method
includes a step of building a fuel powder manufacturing unit
configured for converting UF.sub.6 into UO.sub.2 and connecting the
fuel powder manufacturing unit to the fuel pellet manufacturing
unit; [0043] said method includes building an additional
manufacturing unit which is another fuel assembly manufacturing
unit for increasing manufacturing capacity. [0044] said method
includes a step of building an additional fuel pellet manufacturing
unit configured for manufacturing UO.sub.2 based nuclear fuel
pellets and connecting the additional fuel pellet manufacturing
unit to the additional fuel rod manufacturing unit; [0045] said
method includes a step of building an additional fuel powder
manufacturing unit configured for converting UF.sub.6 into UO.sub.2
and connecting the additional fuel powder manufacturing unit to the
additional fuel pellet manufacturing unit.
BRIEF SUMMARY OF THE DRAWINGS
[0046] The present disclosure and its advantages will be better
understood upon reading the following description given solely by
way of example and with reference to the appended drawings, in
which:
[0047] FIG. 1 is a side elevation view of a nuclear fuel
assembly;
[0048] FIGS. 2 and 3 are respectively a perspective view and a top
view of a nuclear fuel assembly manufacturing plant;
[0049] FIGS. 4 and 5 are respectively a perspective view and a top
view of a nuclear fuel assembly manufacturing plant;
[0050] FIG. 6 is a perspective view illustrating pellet
transportation sheets and a pellet tray, as well as the transfer of
pellets from one of the pellet transportation sheets to the pellet
tray;
[0051] FIG. 7 is a perspective view illustrating a transfer of
pellets from a pellet transportation sheet to a pellet tray;
[0052] FIG. 8 is a perspective view illustrating a transfer of
pellets from a pellet tray to another pellet tray;
[0053] FIG. 9 is a perspective view illustrating a stack of pellet
trays;
[0054] FIG. 10 is a perspective view illustrating a movable vault
for storing pellet trays;
[0055] FIG. 11 is a partial perspective view of the nuclear fuel
assembly manufacturing plant of FIGS. 4 and 5;
[0056] FIG. 12 is a perspective view of a cleaning station and an
inspection station;
[0057] FIG. 13 is a perspective view of a nuclear fuel assembly
manufacturing plant;
[0058] FIGS. 14 and 15 are respectively a perspective view and a
top view of a nuclear fuel assembly manufacturing plant.
DETAILED DESCRIPTION
[0059] According to one aspect, the present disclosure relates to a
method for manufacturing a nuclear fuel assembly comprising nuclear
fuel rods arranged in a bundle and a skeleton supporting the
nuclear fuel rods.
[0060] The nuclear fuel assembly 2 of FIG. 1 comprises a bundle of
nuclear fuel rods 4 and a skeleton 6 for supporting the fuel rods
4. The fuel rods 4 extend parallel to each other and to an assembly
axis L.
[0061] The skeleton 6 comprises a bottom nozzle 8, a top nozzle 10,
a plurality of guide thimbles 12 and a plurality of spacer grids
14.
[0062] The guide thimbles 12 extend parallel to the assembly axis L
and connect the bottom nozzle 8 to the top nozzle 10 with
maintaining a predetermined spacing along assembly axis L between
the bottom nozzle 8 and the top nozzle 10. The fuel rods 4 are
received between the bottom nozzle 8 and the top nozzle 10.
[0063] The spacer grids 14 are distributed along the bundle of fuel
rods 4. Each spacer grid 14 is fixedly attached to the guide
thimbles 12 which extend through the spacer grid 14.
[0064] Each spacer grid 14 is configured for supporting the fuel
rods 4 in a spaced relationship. Each spacer grid 14 is configured
for supporting the fuel rods 4 along the assembly axis L and
transversely to the assembly axis L.
[0065] The fuel assembly 2 is configured for insertion of rods of a
rod cluster control assembly (RCCA) and/or thimble plugs of a
thimble plug assembly (TPA) into the guide thimbles 12, the rods or
thimble plugs being inserted through the top nozzle 10.
[0066] A rod cluster control assembly (RCCA) includes a bundle of
parallel control rods and possibly non-absorber rods arranged for
insertion in the guide thimbles 12, each control rod including
neutron absorbing material. Such an RCCA is provided in a nuclear
reactor and is for example vertically movable up and down for
increasing or decreasing the reactivity of the fuel assembly 2 or
fixedly inserted into a specific fuel assembly 2 for reducing
reactivity of the nuclear reactor in the area of this fuel assembly
2, e.g. in a peripheral area of the nuclear reactor.
[0067] A thimble plug assembly (TPA) is provided in a nuclear
reactor and includes a plurality of plugs each configured for
closing a respective guide thimble 12 of a fuel assembly 2 which is
not provided with a RCCA in the nuclear reactor, in view of
preventing bypass flow of coolant inside the guide thimbles 12 of
this fuel assembly 2.
[0068] In view of manufacturing a fuel assembly 2, it is possible
to provide the skeleton 6 without the bottom nozzle 8 or the top
nozzle 10, to insert the fuel rods 4 axially through the spacer
grids 14 and to fixedly attach the bottom nozzle 8 or the top
nozzle 10 to the guide thimbles 12 to complete the skeleton 6.
[0069] The length of a fuel assembly 2 is for example of between 4
m and 6 m and the weight of a fuel assembly 2 is typically of
between 700 kg and 900 kg.
[0070] The nuclear fuel assembly manufacturing method comprises the
steps of inserting fuel rods 4 into the skeleton 6 to obtain a fuel
assembly 2 and packaging the fuel assembly 2 in view of
transportation, the steps being performed in a same nuclear fuel
assembly manufacturing plant, preferably in a same nuclear fuel
assembly manufacturing building.
[0071] In one particular embodiment, the method comprises a step of
receiving fuel rods 4 transported from a nuclear fuel rod
manufacturing plant separated by a non-confined area from the
nuclear fuel assembly manufacturing plant, wherein these fuel rods
4 are used during the inserting step.
[0072] In the present disclosure, "separated by a non-confined
area" means that the two plants or buildings are not connected in a
confined manner. A transport of skeleton parts or nuclear fuel rods
or nuclear fuel pellets or nuclear fuel powder or nuclear fuel
powder precursor between the two plants or buildings separated by a
non-confined area is performed e.g. via road, sea and/or air.
[0073] In this embodiment, the fuel rods 4 are not manufactured in
the nuclear fuel assembly manufacturing plant. The fuel rods 4 are
manufactured in a nuclear fuel rod manufacturing plant that is
distinct from the nuclear fuel assembly manufacturing plant. The
fuel rods 4 may be transported from the nuclear fuel rod
manufacturing plant to the nuclear fuel assembly manufacturing
plant via road, sea and/or air.
[0074] In one particular embodiment, the method comprises receiving
skeleton parts from a skeleton manufacturing plant separated by a
non-confined area from the nuclear fuel assembly manufacturing
plant, using these skeleton parts in the insertion step.
[0075] In one particular embodiment, the method comprises receiving
preassembled skeleton assemblies, each skeleton assembly comprising
guide thimbles 12, spacer grids 14 and only one among the top
nozzle 10 and the bottom nozzle 8, e.g. one among the top nozzle 10
and the bottom nozzle 8, and, separately, the other one among the
top nozzle 10 and the bottom nozzle 8.
[0076] The method thus comprises, after the inserting step, a step
of assembling the other among the bottom nozzle 8 or the top nozzle
10 to the preassembled skeleton assembly to complete the skeleton
6.
[0077] Optionally, the method comprises receiving fuel rods 4 in a
container and using this container in the packaging step for
packaging a fuel assembly 2.
[0078] Indeed, fuel rods 4 and fuel assemblies 2 can be transported
in same containers, e.g. the fuel assembly containers of the
Framatome company named "FCC".
[0079] For example, fuel rods 4 can be placed in a holster having
substantially the same external dimensions as a corresponding fuel
assembly 2, the holster being placed in the container.
[0080] The reuse of the containers allows to limit the transport
operations by using the same containers for transporting the fuel
rods 4 from the nuclear fuel rod manufacturing plant to the nuclear
fuel assembly manufacturing plant and then for transporting the
fuel assemblies from the nuclear fuel assembly manufacturing plant
to the nuclear power plant.
[0081] Alternatively, the method comprises using dedicated first
containers for transporting nuclear fuel assemblies 2 and dedicated
second containers for transporting fuel rods 4, each second
container being e.g. a first container equipped with additional
equipment for allowing packaging of fuel rods 4 in the second
containers.
[0082] The nuclear fuel assembly manufacturing plant 20 of FIGS. 2
and 3 is configured for the implementation of the method of
manufacturing a fuel assembly 2.
[0083] The nuclear fuel assembly manufacturing plant 20 comprises a
fuel assembly manufacturing unit 22 configured for manufacturing
fuel assemblies 2 starting from fuel rods 4 and skeleton parts.
[0084] The fuel assembly manufacturing unit 22 comprises an
inserting station 24 configured for insertion of fuel rods 4 into
the skeleton 6 to obtain a fuel assembly 2 and a packaging station
26 configured for packaging the fuel assembly 2 into a fuel
assembly container 28 in view of transportation, e.g. to a nuclear
power plant. The fuel assembly container 28 is configured for
receiving fuel assemblies 2 and for transporting them via road, air
and/or sea.
[0085] The nuclear fuel assembly manufacturing plant 20 comprises
an assembling hall 30 in which are located namely the inserting
station 24 and the packaging station 26. The inserting station 24
and the packaging station 26 are located in the same assembling
hall 30.
[0086] The fuel assembly manufacturing unit 22 comprises a crane 32
located in the assembling hall 30 for moving the nuclear fuel
assemblies 2 between the stations located inside the assembling
hall 30.
[0087] The crane 32 is notably configured for moving the nuclear
fuel assemblies 2 between the inserting station 24 and the
packaging station 26. Advantageously, the crane 32 is a bridge
crane.
[0088] The fuel assembly manufacturing unit 22 optionally comprises
a cleaning station 34 configured for cleaning a nuclear fuel
assembly 2.
[0089] The cleaning station 34 is for example located in the
assembling hall 30. Hence, the fuel assembly 2 can be loaded into
and/or taken form the cleaning station 34 using the crane 32.
[0090] The fuel assembly manufacturing unit 22 optionally comprises
a fuel assembly inspection station 36 configured for the inspection
of a fuel assembly 2.
[0091] The fuel assembly inspection station 36 is for example
located in the assembling hall 30. Hence, the fuel assembly 2 can
be loaded into and/or taken form the fuel assembly inspection
station 36 using the crane 32.
[0092] Advantageously, the cleaning station 34 is configured for
cleaning of the fuel assembly 2 in a vertical position and/or
substantially at ground level and/or the fuel assembly inspection
station 36 is configured for inspection of the fuel assembly 2 in a
vertical position and/or substantially at ground level.
[0093] The vertical position of the fuel assembly 2 for cleaning
and/or inspection allows reducing the footprint of the fuel
assembly manufacturing unit 22.
[0094] Having the fuel assembly 2 at ground level instead of
placing the fuel assembly 2 into a pit provided into the ground
avoids the provision of such a pit which can be rendered difficult
depending on the nature of the ground.
[0095] It however requires that the hall in which the cleaning
station 34 or the fuel assembly inspection station 36 is located,
here the assembling hall 30, has a height which is sufficient for
accommodating the fuel assembly 2 vertically.
[0096] Optionally, the cleaning station 34 is also configured for
performing a rod cluster control assembly test (or "RCCA test")
and/or a thimble plug assembly test (or "TPA test") while the fuel
assembly 2 is in the cleaning position.
[0097] This allows reducing footprint of the fuel assembly
manufacturing unit 22 by performing cleaning as well as RCCA test
and/or TPA test in a same station instead of providing respective
stations for cleaning, RCCA test and TPA test.
[0098] A RCCA test is a test of insertion the control rods of a
RCCA into the fuel assembly 2 to ensure that, in operation, the
RCCA will properly insert into the guide thimbles 12 of the fuel
assembly 2. A deformation of the fuel assembly 2 or a foreign body
located in a guide thimble 12 may prevent proper insertion of the
RCCA. Similarly, a TPA test is a test of insertion the thimble
plugs of a TPA into the guide thimbles 12 of the fuel assembly
2.
[0099] The fuel assembly inspection station 36 is configured for
performing geometrical measurements and/or visual inspection.
[0100] Preferably, the fuel assembly inspection station 36 is
configured for performing both geometrical measurements and visual
inspection. This allows reducing footprint of the fuel assembly
manufacturing unit 22 by performing geometrical measurements and
visual inspection in a same station instead of providing respective
stations for geometrical measurements and visual inspection.
[0101] Geometrical measurements may include for example a distance
between fuel rods 4, a distance between fuel rods 4 and guide
thimbles 12, an external envelope of the fuel assembly 2, a
verticality of the fuel assembly 2 . . .
[0102] Geometrical measurements are performed with instruments. The
fuel assembly inspection station 36 comprises for example a
measurement assembly which is vertically movable along a fuel
assembly 2 received in the fuel assembly inspection station 36, the
measurement assembly comprising the instruments.
[0103] Visual inspection is performed for example for detecting any
foreign body that may be present within the bundle of fuel rods
4.
[0104] The fuel assembly manufacturing unit 22 optionally comprises
a fuel rod inspection station 38 configured for the inspection of
fuel rods 4 received from the nuclear fuel rod manufacturing plant.
The fuel rod inspection station 38 is for example located in the
assembling hall 30.
[0105] The fuel assembly manufacturing unit 22 optionally comprises
a fuel rod storage 40 configured for the storage of fuel rods 4
received from the nuclear fuel rod manufacturing plant. The fuel
rod storage 40 is for example located in the assembling hall 30.
The fuel rod storage 40 comprises for example racks for storing the
fuel rods 4 horizontally.
[0106] The fuel assembly manufacturing unit 22 optionally comprises
a fuel assembly storage 42 configured for storing nuclear fuel
assemblies 2 before cleaning, inspecting and/or packaging the
nuclear fuel assemblies 2.
[0107] The fuel assembly storage 42 is for example located in the
assembling hall 30. Hence, a nuclear fuel assembly 2 can be loaded
into and/or taken from the fuel assembly storage 42 using the crane
32.
[0108] The fuel assembly storage 42 is for example a room delimited
inside the assembling hall 30.
[0109] The fuel assembly storage 42 comprises for examples racks
for storing each fuel assembly 2 in a vertical position.
[0110] Alternatively or optionally, the nuclear fuel assemblies 2
may be stored into fuel assembly containers 28, preferably after
cleaning and/or inspection. The nuclear fuel assemblies 2 stored in
the fuel assembly containers 28 are ready to be sent to a nuclear
power plant.
[0111] The fuel assembly manufacturing unit 22 optionally comprises
a logistic area 46 configured for storing, receiving and/or sending
transport containers.
[0112] The logistic area 46 is accessible from the exterior of the
fuel assembly manufacturing unit 22 via a door 48 opening to the
exterior. Preferably, the logistic area 46 is accessible to trucks
and/or forklifts.
[0113] Optionally, the logistic area 46 is provided with a logistic
area bridge crane 54 dedicated to the logistic area 46. This
logistic area bridge crane 54 is configured for example for lifting
transport containers, notably fuel assembly containers 28 as well
as fuel rod containers. The logistic area bridge crane 54 may be
omitted, in which case handling operations may be performed using
for instance a forklift. However, the logistic area bridge crane 54
provides more flexibility.
[0114] Preferably, the packaging station 26 is located in the
assembling hall 30 with being adjacent to the logistic area 46.
Hence, a fuel assembly container 28 receiving a fuel assembly 2 can
be moved from the packaging station 26 to the logistic area 46
easily.
[0115] In one particular embodiment, the logistic area 46 comprises
a container storage zone 56 for storing transport containers. As
illustrated on FIG. 1, several fuel assembly containers 28 are
present in the container storage zone 56.
[0116] The nuclear fuel assembly manufacturing plant 20 optionally
comprises a component area 58 which is configured for inspecting
and storing skeleton parts.
[0117] As illustrated on FIG. 2, the fuel assembly manufacturing
unit 22 is housed in a building 60 made of two building modules 62,
64 arranged side-by-side in an alignment direction A. For example,
the two building modules 62, 64 are each of rectangular shape and
of substantially the same dimensions (length, width and
height).
[0118] The stations (inserting station 24, packaging station 26 . .
. ) and equipment (crane(s), storages . . . ) of the fuel assembly
manufacturing unit 22 are located in the two building modules 62,
64.
[0119] The logistic area 46 is located in a first building module
62 among the two building modules 62, 64 and the inserting station
24 and the packaging station 26 are located in the second building
module 64 among the two building modules 62, 64.
[0120] Where the case may be, as in the illustrated in FIG. 3, the
component area 58 is for example located in the same building
module as the logistic area 46, i.e. here the first building module
62.
[0121] Where the case may be, as illustrated in FIG. 3, the
cleaning station 34, the fuel assembly inspection station 36, the
fuel rod inspection station 38, the fuel rod storage 40 and/or the
fuel assembly storage 42 is/are for example located in the same
building module as the inserting station 24 and the packaging
station 26, i.e. here the second building module 64.
[0122] In the illustrated example, the logistic area 46 and the
component area 58 located in the first building module 62 each
communicate with the second building module 64, and more
particularly with the assembling hall 30, via respective passages
66, 68.
[0123] The passage 66 between the logistic area 46 and the
assembling hall 30 is adjacent the packaging station 26 and/or the
passage 68 between the component area 58 and the assembling hall 30
is adjacent the inserting station 24.
[0124] For example, the cleaning station 34, the fuel assembly
inspection station 36, the fuel rod storage 40 and/or the fuel
assembly storage 42 are located in the assembling hall 30 between
these two passages 66, 68.
[0125] In the illustrated example, the method for manufacturing a
nuclear fuel assembly 2 comprises: [0126] receiving the fuel rods
4, inspecting the fuel rods 4 in the fuel rod inspection station 38
and transferring the inspected fuel rods 4 to the inserting station
24; [0127] receiving the skeleton parts and inspecting the skeleton
parts in the component area 58 and transferring the skeleton parts
to the inserting station 24; [0128] inserting the fuel rods 4 into
the skeleton 6 deprived of bottom nozzle 8 and/or top nozzle 10 and
attaching the bottom nozzle 8 and/or the top nozzle 10 of the
skeleton 6 to complete the skeleton 6, thus obtaining a fuel
assembly 2; [0129] cleaning the fuel assembly 2 in the cleaning
station 34 and/or inspecting the fuel assembly 2 in the fuel
assembly inspection station 36 ; [0130] packaging the fuel assembly
2 into a fuel assembly container 28 in the packaging station 26;
[0131] transferring the fuel assembly container 28 to the logistic
area 46 for sending the fuel assembly container 28 to a nuclear
power plant.
[0132] Insertion of the fuel rods 4 may be performed from top to
bottom of the fuel assembly 2, the top nozzle 10 being omitted or
removed, or from bottom to top of the fuel assembly 2, the bottom
nozzle 8 being omitted or removed. Besides, insertion of the fuel
rods 4 may be performed by pushing and/or pulling each fuel rod
4.
[0133] In one exemplary embodiment, the insertion station 24 is
configured for sequentially inserting groups of fuel rods into the
skeleton 6, each group of fuel rods being prepared manually and
then inserted automatically into the skeleton 6. The fuel rods of
each group are to be inserted at a same elevation of the skeleton 6
lying on an insertion bench of the insertion station 24.
[0134] In a specific exemplary embodiment, the insertion step
comprises: [0135] gather fuel rods. The fuel rods may be gathered
from a fuel rod inspection bench or from a fuel rod storage by mean
of at least one fuel rod transfer trolley; [0136] move the fuel rod
manually to a fuel rod group preparation table by following a
sequence displayed by a fuel assembly software executed by a
computer in accordance with a fuel rod position map; [0137]
transfer the fuel rod manually to a lift table with spacing the
fuel rods manually according to the fuel rod position map; [0138]
check the fuel rods for cleanliness and absence of damages; [0139]
check the fuel rod arrangement according the fuel rod position map;
[0140] check the identification of fuel rods and release them for
assembling; [0141] semi-automatic positioning of the lift table and
the fuel rods to the adequate elevation according to the fuel road
positioning map; [0142] automatic insertion of the fuel rods into
the skeleton 6 by pulling and/or pushing.
[0143] In the case the fuel rods are inserted into the skeleton 6
by pulling, the insertion step may comprise: [0144] checking that a
pulling assembly is at home position and place manually protection
caps on tie rods configured for pulling the fuel rods through the
skeleton 6; [0145] insert the tie rods into the skeleton and remove
manually the protection caps, and [0146] during the automatic
insertion : activation of a lubrication system, pushing of the fuel
rod to a gripping position, gripping of the fuel rods and pulling
of the fuels through the skeleton. Pulling speed may be checked
manually during insertion of a fuel rod, e.g. the first inserted
fuel rod.
[0147] Optionally, the insertion step comprises, during insertion,
checking that lubricant (e.g. water) is applied on the fuel rod,
after insertion, checking the setting of the pulling assembly by
measuring a distance between the fuel rod ends and shoulders of the
guide thimbles plugs, checking the presence orientation and
position of the fuel rods and/or checking visually the spacer grids
and the fuel rods end plugs for damages.
[0148] These operations are repeated for each group of fuel rods
according to the fuel rod position map, until all the necessary
fuel rods are inserted into the skeleton 6.
[0149] Optionally, the insertion step includes insertion of fuel
rods containing a neutron poison. The neutron poison contains for
example Gadolinium (Gd). In such case, the fuel rods without
neutron poison and the fuel rods with neutron poison are preferably
stored in different places. For example, the fuel rods containing
neutron poison are stored on a dedicated trolley separated from
storage for the fuel rods without neutron poison.
[0150] Upon preparing a group of fuel rods to be inserted at a same
level in the skeleton 6, the operator is guided by the fuel rod
insertion map to place the fuel rods without neutron poison and the
fuel rods with neutron poison at the appropriate place on the
lift-table.
[0151] Hence, the groups of fuel rods with and/or without neutron
poison are prepared manually on the lifting table with indication
from the fuel rod insertion map displayed by a fuel assembly
software executed by a computer.
[0152] The nuclear fuel assembly manufacturing method and the
corresponding nuclear fuel assembly manufacturing plant 20 allows
manufacturing fuel assemblies 2 efficiently and with minimized
constrains.
[0153] The fuel rods 4 are not manufactured inside the nuclear fuel
assembly manufacturing plant 20. The manufacture of the nuclear
fuel assembly 2 is operated using fuel rods 4 transported from a
nuclear fuel rod manufacturing plant in a non-confined area. Fuel
rods 4 can be easily transported by road, air and/or sea.
[0154] It is thus possible to produce fuel assemblies 2 simply and
efficiently in a specific nuclear fuel assembly manufacturing plant
20 at proximity of one or several nuclear power plant(s).
[0155] Operations can be performed manually without the need to
resort to automatization of some tasks. It is thus easier to start
production of nuclear fuel assemblies and to invest in the nuclear
fuel assembly manufacturing plant 20.
[0156] In a specific embodiment, the nuclear fuel assembly
manufacturing method comprises receiving pellets transported from a
nuclear fuel pellet manufacturing plant separated by a non-confined
area from the nuclear fuel assembly manufacturing plant 20, using
these pellets to manufacture fuel rods 4, and using these fuel rods
4 to manufacture fuel assemblies 2 in the nuclear fuel assembly
manufacturing plant 20.
[0157] The nuclear fuel assembly manufacturing method comprises for
example placing the pellets on pellet trays, optionally inserting
the trays in an outgassing furnace for removing potential
hydrogenous contamination from the pellets, loading the pellets
from the pellet trays into a cladding tube in a fuel rod loading
station, inserting a spring into the cladding tube, filling the
cladding tube with helium gas and/or welding plugs at the ends of
the cladding tubes for closing the fuel rod 4.
[0158] The nuclear fuel assembly manufacturing plant 20 of FIGS. 4
and 5 is configured for implementing such an embodiment of the fuel
assembly manufacturing method.
[0159] The nuclear fuel assembly manufacturing plant 20 of FIGS. 4
and 5 differs from that of FIGS. 2 and 3 in that it further
comprises a fuel rod manufacturing unit 70 configured for receiving
pellets transported from a nuclear fuel pellet manufacturing plant
separated by a non-confined area from the nuclear fuel assembly
manufacturing plant 20 and to manufacture fuel rods 4 using these
pellets, the fuel rods 4 being in turn used in the inserting
step.
[0160] The fuel rod manufacturing unit 70 comprises for example a
pellet receiving area 72 configured for receiving pellets, a pellet
inspection area 74 configured for inspecting the pellets, an
outgassing station 76 comprising at least one outgassing furnace 78
configured to expel potential hydrogenous contamination of the
pellets, a cladding station 79 configured to receive cladding tubes
and check the received cladding tubes, a fuel rod loading station
80 configured for loading the pellets into a cladding tube, a
welding station 82 configured for welding plugs to the ends of the
cladding tubes and/or a fuel rod inspection area 84 configured for
inspecting the fuel rods 4.
[0161] The pellet receiving area 72 is configured for receiving the
pellets packed in pellet containers 86 and for temporarily storing
the pellets with leaving the pellets in these pellet containers
86.
[0162] Each pellet container 86 comprises for example a sealed
casing containing several pellet transportation sheets and an outer
shell, a structure, the outer shell structure being configured for
packing the pellet containers 86 in an intermodal shipping
container.
[0163] The pellet transportation sheets are metallic corrugated
sheets which comprise several parallel ridges and furrows, each
furrow being configured for receiving a column of nuclear fuel
pellets.
[0164] The pellet inspection area 74 is configured for unpacking
the pellet transportation sheets from the pellet containers 86,
transferring the pellets from a pellet transportation sheet onto a
pellet tray and inspecting visually the nuclear pellets.
[0165] These operations are for example done manually. Placing the
pellets on trays is for example performed by sliding manually all
pellet columns from the pellet transportation sheet onto a pellet
tray. Inspecting visually the pellets is for example performed by
inspecting the visible surface of the pellets located on a pellet
tray, then placing upside down a second pellet tray on the top of
the pellets, returning both pellet trays together, removing the
first pellet tray and finally inspecting the other visible surface
of the pellets.
[0166] As illustrated on FIG. 6, each pellet transportation sheet
124 has parallel furrows 126 configured for receiving pellets 128
arranged in pellet columns 130.
[0167] Each pellet transportation sheet 124 is for example a
metallic corrugated sheet comprising ridges alternating with the
furrows 126.
[0168] Each pellet tray 132 has for example parallel bars 134
defining between them grooves configured for receiving pellets 128
arranged in pellet columns 130.
[0169] In a preferred embodiment, as illustrated on FIG. 6, the
pellet transportation sheets 124 and the pellet trays 132 are
different but geometrically compatible to allow transfer of pellet
columns 130 from a pellet transportation sheet 124 to a pellet tray
132.
[0170] More specifically, the pitch P between the furrows 126 of a
pellet transportation sheet 124 and the pitch P between the bars
134 of a pellet tray 132 are substantially equal, the pellet
transportation sheet 124 and the pellet tray 132 comprise as many
furrows 126 as grooves between the bars 134 and the length D of the
furrows 126 of the pellet transportation sheet 124 is substantially
equal to that of the bars 134 of the pellet tray 132.
[0171] In one exemplary embodiment, transferring pellets 128 from a
pellet transportation sheet 124 to a pellet tray 132 includes
placing the pellet tray 132 side-by-side with the pellet
transportation sheet 124 such that each furrows 126 of the pellet
transportation sheet 124 is aligned with a respective groove
between bars 134 of the pellet tray 132 as illustrated on FIG. 6,
and sliding each pellet column 130 of the pellet transportation
sheet 124 into a groove of the pellet tray 132.
[0172] Alternatively or optionally, as illustrated on FIG. 7,
transferring pellets 128 from a pellet transportation sheet 124 to
a pellet tray 132 includes placing the pellet tray 132 upside down
on the pellet transportation sheet 124 such that each pellet column
130 is received in a respective groove between the bars 134 of the
pellet tray 132, and then turning the assembly composed of the
pellet transportation sheet 124 and the pellet tray 132 upside down
such that the pellet tray 132 is below and the pellet
transportation sheet 124 above, and removing the pellet
transportation sheet 124.
[0173] Such transferring with turning allows a visual inspection of
both faces of the pellets 128 since a face is visible when the
pellets 128 are on the pellet transportation sheet 124 and the
other face of the pellets 128 is then visible the pellets 128
having been transferred to the pellet tray 132 with an upside down
tuning.
[0174] Alternatively or optionally, as illustrated on FIG. 8, such
turning of pellets 128 is performed by using two pellet trays 132.
The pellets 128 are for examples transferred from a pellet
transportation sheet 124 to a pellet tray as illustrated on FIG. 6
and then turned upside-down between two pellet trays 132 as
illustrated on FIG. 8.
[0175] Advantageously, as illustrated on FIG. 9, the pellet trays
132 are configured for stacking the pellet trays 132. This eases
handling of the pellet trays 132, namely transporting the pellet
trays 132 and/or transferring them to outgassing furnaces 79.
[0176] The pellet transportation sheets 124 and the pellet trays
132 are for example different in their design (e.g. material and/or
structure), the pellet trays 132 being e.g. designed to resist to
heating in the outgassing furnace 78.
[0177] Advantageously, these pellet trays 132 are configured to be
used for storing the pellets 128 and/or placing the pellets 128
into an outgassing furnace 78 and/or loading the pellets 128 into
cladding tubes.
[0178] The pellets 128 can thus remain on the pellet trays 132 from
the inspection to the loading into cladding tubes, without transfer
of the pellets 128 from the pellet tray 132 to another support or
container between the inspection and the loading. This limits
manipulation of the pellets 128 and thus limits the risk of
damaging the pellets 128.
[0179] Optionally, the fuel rod manufacturing unit 70 comprises
movable pellet storage vaults 140, each storage vault 140 being
configured for storing pellet trays 132 and movable to allow
transferring pellet trays 132.
[0180] As illustrated on FIG. 10, each storage vault 140 is
configured for receiving several pellet trays 132, and comprises
e.g. several compartments or cells 142, each cell 142 being
configured for receiving several pellet trays 132.
[0181] Each storage vault 140 comprises for examples several cells
142, each cell 142 being configured for receiving a stack of pellet
trays 132 for example equivalent to the stack of pellet
transportation sheets 124 from a pellet container 86.
[0182] Each cell 142 is preferably provided with a door for closing
the cell 142.
[0183] Preferably, the cells 142 are distributed on two opposite
faces 140A, 140B of the storage vault 140. This allows improving
stability of the storage vault 140, increasing storage capacity and
also loading two side-by-side outgassing furnaces 78 with pellet
tray 132 from both sides of the storage vault 140, without having
to turn the storage vault 140. The storage vault 140 is for example
positioned between the two outgassing furnaces 78, each outgassing
furnace 78 being loading respectively with the pellet trays 132 of
one side of the storage vault 140.
[0184] Each storage vault 140 exhibits a parallelepiped shape with
cells 142 located on two opposite faces 140A, 140B of the storage
vault 140.
[0185] Each storage vault 140 can be moved and/or elevated easily,
e.g. with a standard pallet stacker 146. The pallet stacker 146
allows moving the storage vaults 140 between pellet inspection area
74, storage location, outgassing furnace 78 and fuel rod loading
station 80. Elevation eases the manual loading and unloading of
pellet trays 132 inside and/or outside the storage vault 140.
[0186] Pellet scraps (i.e. pellets with non-compliant surface
flaws) may be unintentionally produced during handling of the
pellets, namely during inspection, storing, outgassing and/or
loading.
[0187] Optionally, the method comprises returning pellet scraps to
the nuclear fuel pellet manufacturing plant in the pellet
containers 86. This allows benefiting from the return of the pellet
containers 86 to the nuclear fuel pellet manufacturing plant
knowing that the fuel rod manufacturing unit 70 is not configured
for manufacturing nuclear fuel pellets and is deprived of equipment
for processing pellet scraps.
[0188] Optionally, the method comprises temporarily storing pellet
scraps in at least one pellet container 86 in the pellet receiving
area 72 and/or in at least one cell 142 of a storage vault 140.
Pellet scraps may be stored in a can, the can being stored
temporarily in a pellet container 86 or storage vault 140. The
outgassing station 76 comprises at least one outgassing furnace 78.
Each outgassing furnace 78 is configured for expelling potential
hydrogenous contamination of the pellets.
[0189] Each outgassing furnace 78 is configured for receiving the
pellet trays 132 containing the pellets, such that the pellets can
be left in the pellet trays 132 for outgassing heating operation,
without transfer of the pellets.
[0190] As illustrated on FIGS. 4 and 5, the outgassing station 76
is located in a room which is provided with dedicated locations for
storing the storage vaults 140.
[0191] In one embodiment, the method comprises receiving and
inspecting cladding tubes to be filled with nuclear fuel pellets
for obtaining the fuel rods 4.
[0192] The cladding tubes are for example shipped in wooden boxes
and unloaded manually.
[0193] The step of inspecting the cladding tubes comprises for
example inspecting visually for transport damages (e.g. dents and
scratches), checking that the cladding tube is empty and or drying
the inside of the cladding tube to avoid presence of moisture.
[0194] Emptiness is checked e.g. using an optical emptiness
checking device configured for projecting a light beam inside the
cladding from one end and capturing light at the other end to check
for any object obstructing propagation of the light.
[0195] Drying is performed e.g. by a drying device, blowing hot air
inside the cladding tube.
[0196] As illustrated on FIG. 5, the fuel rod manufacturing unit 70
comprises a cladding station 79.
[0197] The cladding station 79 is configured for receiving the
cladding tubes and performing the inspection of the received
cladding tubes, and namely comprises for example an emptiness
checking device and a drying device.
[0198] The welding station 82 and the fuel rod loading station 80
are configured to perform all the manufacturing steps of a fuel rod
4.
[0199] The manufacturing of a fuel rod 4 comprises for example the
following steps: [0200] weighing the cladding tube with a weighing
device of the welding station 82; [0201] welding a plug at a first
end of the cladding tube with a welding machine of the welding
station 82, thus obtaining a pre-plugged cladding tube; [0202]
inspecting the first end plug weld; [0203] loading pellets into the
pre-plugged cladding tube and checking the pellet plenum length
with the fuel rod loading station 80; [0204] turning the
pre-plugged cladding tube such as to present the second end of the
cladding tube to the welding device, by mean for example of an
inversion trolley available in the welding station 82;
[0205] weighing the cladding tube with the weighing device of the
welding station 82 such as to determine the uranium content of the
fuel rod 4; [0206] inserting a spring at the second end of the
cladding tube; [0207] filling the cladding tube with helium gas and
welding a plug at the second end of the cladding tube with the
welding machine of welding station 82, thus obtaining the fuel rod
4; [0208] inspecting the second end plug weld; [0209] checking the
absence of contamination on the fuel rod surface; and releasing the
fuel rod 4 to the fuel rod inspection area 84.
[0210] Such loading including a turning step allows performing the
loading with one single welding machine.
[0211] This allows minimizing the footprint of the welding station
82 and minimizing the cost of the fuel rod manufacturing unit 70 by
avoiding the provision of two distinct welding machines. Turning
the nuclear fuel rod 4 between welding of the plugs is time
consuming but this is acceptable in the context of the rate of
production foreseen for the fuel rod manufacturing unit 70.
[0212] In addition, only one weighing device is needed. Weighing
each cladding tube before and after filling with pellets allows to
determine the uranium content.
[0213] Hence advantageously, the welding station 82 comprises one
single welding machine and/or one single weighing device.
[0214] The loading of fuel rods 4 can advantageously be performed
batchwise.
[0215] In such case, the empty weighing, plug welding, and pellet
filling steps are operated for a batch of cladding tubes, theses
cladding tubes are turned, and then the following steps of filled
weighing, spring inserting, plug welding and releasing are
performed for the batch of cladding tubes. Each batch of fuel rods
4 comprises for example approximately hundred fuel rods 4.
[0216] The fuel rod loading station 80 is advantageously configured
for creating pellet columns 130 and loading each pellet column 130
into a cladding tube. Preferably, the fuel rod loading station 80
is configured for creating a pellet column 130 at the specified
length for loading into a next cladding tube while a previously
created pellet column 130 is being loaded into a preceding cladding
tube.
[0217] The method preferably comprises a step of inspecting the
fuel rods 4, i.e. once the fuel rods 4 are released from the
welding station 82.
[0218] The step of inspecting the fuel rods 4 may comprise scanning
each fuel rod 4 for inspecting the fuel rod 4 in a nondestructive
manner, testing helium leak of the fuel rod 4 and performing a
final inspection including e.g. measuring the length of the fuel
rod 4, checking straightness of the fuel rod 4 and/or checking the
fuel rod visual appearance.
[0219] Accordingly, the fuel rod inspection area 84 comprises one
or several fuel rod inspection station(s).
[0220] A fuel rod inspection station is for example a leak testing
station 88, in particular a helium leak testing station. Such a
leak testing station 88 is configured for identifying possible
leaks of the fuel rod 4, namely leaks of the fuel rod cladding, of
the plugs and/or between the fuel rod cladding and one of the
plugs.
[0221] Another fuel rod inspection station is for example a
scanning station 90 configured for inspecting the fuel rods 4 in a
nondestructive manner. The scanning station 90 is for example
configured for passively scanning the gamma radiation emission
count of the nuclear fuel pellets contained within the fuel rod 4
to check the enrichment level(s) and uniformity throughout the fuel
rod 4. Additionally, the scanning station 90 is for example
configured for performing a gamma densitometer test to check the
pellet column and plenum lengths, the presence of the required
components such as the fuel rod spring and the absence of gaps
between the pellets.
[0222] Another fuel rod inspection station is for example a final
inspection station 91 configured for checking of geometrical
characteristics of the fuel rod 4, in particular measuring length
of the fuel rod 4, checking straightness of the fuel rod 4 and/or
checking visual appearance of the fuel rod 4. The final inspection
station 91 comprises for example an inspection bench having a
planar workplan.
[0223] The fuel rod manufacturing unit 70 optionally comprises a
nuclear fuel rod rework station 92 configured for reworking a
nuclear fuel rod 4 which has been identified as faulty during
nuclear fuel rod inspection in the fuel rod inspection area 84 or
during the fuel rod manufacturing in the welding station 82.
[0224] The fuel rod manufacturing unit 70 comprises a controlled
atmosphere enclosure 94 in which the atmosphere is controlled to
ensure personnel safety and avoid the exit of particles of nuclear
fuel that may arise from the pellets. The contour of the controlled
atmosphere enclosure 94 is show in dotted lines of FIG. 5.
[0225] The controlled atmosphere enclosure 94 extends to the
stations where the pellets are not sealed into the fuel rods 4.
[0226] In particular, in the present example, the pellet inspection
area 74, the outgassing station 76, the fuel rod loading station 80
and the welding station 82 are located in the controlled atmosphere
enclosure 94.
[0227] The controlled atmosphere enclosure 94 is separated from the
remaining of the fuel rod manufacturing unit 70, namely from the
pellet receiving area 72, from the fuel rod inspection area 84 and
from the cladding station 79, including the emptiness checking
device and the drying device.
[0228] The controlled atmosphere enclosure 94 is accessible to
operators via a controlled entrance 96 and a controlled exit
98.
[0229] As illustrated on FIG. 4, the fuel rod manufacturing unit 70
is connected to the fuel assembly manufacturing unit 22 in a
confined manner.
[0230] In the present disclosure two units or buildings or building
modules are said to be connected "in a confined manner" when
material can be transferred from one unit to the other of from one
building to the other or from one building module to the other
without transiting via the exterior.
[0231] The fuel rod manufacturing unit 70 and the fuel assembly
manufacturing unit 22 are here placed side-by-side in a same
building.
[0232] As illustrated on FIG. 5, the building 60 includes four
building modules including the first building module 62 and the
second building module 64 housing the fuel assembly manufacturing
unit 22 and a third building module 100 and a fourth building
module 102 housing the fuel rod manufacturing unit 70.
[0233] The welding station 82 and the fuel rod inspection area 84
are located in the third building module 100 which is side-by-side
with the second building module 64. The fuel rods 4 produced in the
fuel rod manufacturing unit 70 can thus be transferred directly
from the fuel rod inspection area 84 to the inserting station
24.
[0234] The pellet receiving area 72, the pellet inspection area 74
and the fuel rod loading station 80 are located in the fourth
building module 102.
[0235] In the present example, the outgassing station 76 and/or the
rework station 92 are located in the fourth building module
102.
[0236] The controlled atmosphere enclosure 94 extends in the fourth
building module 102 and also to the third building module 100 such
as to contain the welding station 82. The third and fourth building
modules 100, 102 are here provided with internal walls for
delimiting the controlled atmosphere enclosure 94 inside the third
and fourth building modules 100, 102.
[0237] Advantageously, in a general manner, the nuclear fuel
assembly manufacturing plant 20 comprises building modules arranged
side-by-side with being aligned in the alignment direction A, the
buildings modules housing several manufacturing units configured
for implementation of respective steps of manufacturing a nuclear
fuel assembly 2 (fuel rod manufacturing unit 70, fuel assembly
manufacturing unit 22, etc.), each manufacturing unit being housed
in one or several of the building modules dedicated to this
manufacturing unit.
[0238] Manufacturing units of the nuclear fuel assembly
manufacturing plant 20 may comprises a fuel assembly manufacturing
unit 22 and/or a fuel rod manufacturing unit 70, and also a fuel
pellet manufacturing unit configured for manufacturing pellets from
nuclear fuel powder and/or a fuel powder manufacturing unit
configured for converting a nuclear fuel precursor into nuclear
fuel powder, e.g. for converting gaseous UF.sub.6 into UO.sub.2
powder.
[0239] As visible on FIGS. 5 and 11, the fuel rod manufacturing
unit 70 comprises conveyors for conveying the fuel rods 4 between
the cladding station 79, the welding station 82, the fuel rod
inspection area 84 and the inserting station 24.
[0240] In the example, the fuel rod manufacturing unit 70 comprises
a first conveying system 104 for conveying fuel rods 4 in a first
direction and a second conveying system 106 for conveying fuel rods
4 in a second direction making a non-zero angle with the first
direction. The second direction is here perpendicular to the first
direction.
[0241] The fuel rod manufacturing unit 70 comprises a pivoting
trolley 108 for transferring the fuel rods 4 from the first
conveying system 104 to the second conveying system 106.
Preferably, the trolley is manually operated.
[0242] This arrangement allows conveying the fuel rods 4 easily
without excessive automatization and with a low footprint of the
fuel rod manufacturing unit 70 and the nuclear fuel assembly
manufacturing plant 20 as a whole.
[0243] The second conveying system 106 is configured for
transferring fuel rods 4 from the fuel rod inspection area 84 to
the insertion station 24. Besides, the second conveying system 106
may be used as buffer storage for storing fuel rods 4 temporarily
between the fuel rod inspection area 84 and the inserting station
24. Such storage avoids any supplementary manual operation.
[0244] In the illustrated embodiment, the first conveying system
104 is configured for conveying cladding tube from the cladding
station 79 to the welding station 82 and for transferring fuel rods
4 from the welding station 82 successively to the fuel rod
inspection stations 90, 88, 91 of the fuel rod inspection area 84,
and the second conveying system 106 is configured for conveying the
fuel rods 4 from the pivoting trolley 108 to the inserting station
24. Fuel rods 4 can be transferred manually from the last fuel rod
inspection station (here final inspection station 91) to the
pivoting trolley 108.
[0245] Each conveying system 104, 106 comprise for example one or
several transfer table(s), each transfer table comprising a
slightly inclined ramp, whereby each cladding tube or fuel rod 4
can roll along the transfer table by gravity.
[0246] For example, one transfer table is provided between each
pair of successive stations for transferring the cladding tube or
fuel rod 4 from each station to the next one.
[0247] The first direction is parallel to the transverse direction
T and the second direction is parallel to the alignment direction A
such that the nuclear fuel rod 4 are conveyed towards the fuel
assembly manufacturing unit 22, more particularly towards the
inserting station 24.
[0248] In the illustrated example, at least one fuel rod inspection
station is located beside the first conveying system 104 and/or a
fuel rod inspection station is located at the end of the first
conveying system 104. For example, the final inspection station 91
is located at the end of the first conveying system 104 and the
other fuel rod inspection station(s) is(are) located successively
beside the first conveying system 104.
[0249] Preferably, each fuel rod inspection station located beside
the first conveying system 104 has its own specific conveying
system for transferring a fuel rod 4 from the first conveying
system 104 to the fuel rod inspection station and returning the
inspected fuel rod 4 to the first conveying system 104.
[0250] The placement of at least one fuel rod inspection station
beside the first conveying system 104 has been chosen to optimize
the footprint with still allowing good working conditions for the
production and maintenance operators.
[0251] In the present case, the fuel rod inspection stations 88, 90
are located beside the first conveying system 104 and distributed
along the first conveying system 104 such that each fuel rod 4 is
conveyed in register with the fuel rod inspection station 90, 88,
inserted into the fuel rod inspection station 90, 88 and
transferred back the first conveying system 104 for being conveyed
in register with the next fuel rod inspection station 90, 88 or to
the final inspection station 91 located at the end of the first
conveying system 104.
[0252] As indicated above, the nuclear fuel assembly manufacturing
method comprises a step of cleaning a nuclear fuel assembly 2
and/or a step of inspecting a nuclear fuel assembly 2.
[0253] The cleaning step and/or the inspecting step is/are
performed with positioning the fuel assembly 2 in a vertical
position and/or substantially at ground level.
[0254] The cleaning step is for example performed by air blowing
cleaning and/or high pressure cleaning and/or washing with bubbling
water and/or brushing cleaning, for example manual brushing
cleaning.
[0255] The cleaning step and/or the inspecting step comprise(s)
visually inspecting the fuel assembly 2 positioned vertically using
at least one elevator for ascending and/or descending along the
fuel assembly 2.
[0256] As illustrated on FIG. 12, a cleaning station 34 is
configured for blowing with compressed air.
[0257] The cleaning station 34 comprises a telescopic enclosure 110
configured for receiving the fuel assembly 2 vertically.
[0258] The telescopic enclosure 110 comprises tubular segments 112
mounted telescopically one onto the others in a vertical direction
such as to be movable between a retracted configuration and
extended configuration in which the telescopic enclosure 110
defines a tube for receiving the fuel assembly 2. The telescopic
enclosure 110 is retracted and extended vertically. In the
retracted position, the tubular segments 112 are for example
retracted downwardly. Alternatively, they are retracted
upwardly.
[0259] Retracting the telescopic enclosure 110 allows placing the
fuel assembly 2 into the telescopic enclosure 110 without the need
to lift the fuel assembly 2 at a high height. Extending the
telescopic enclosure 110 allows enclosing the fuel assembly 2 for
the blowing cleaning, with avoiding spreading of chips (generated
during insertion of fuel rods 4 into the skeleton 6) blown out of
the fuel assembly 2 during blowing cleaning.
[0260] In view of deploying the telescopic enclosure 110, the
cleaning station 34 comprises for example a slide 114 vertically
movable along a tower 116, the slide 114 being connected to a
tubular segment 112 of the telescopic enclosure 110 and to the
blowing nozzle(s).
[0261] The cleaning station 34 comprises for example blowing
nozzles 120 for blowing air through the fuel assembly 2.
[0262] Advantageously, the blowing nozzles 120 are attached to a
tubular segment 112 of the telescopic enclosure 110, such that the
blowing nozzles 120 are moved along the fuel assembly 2 upon
closing the telescopic enclosure 110. Hence, closure of the
telescopic enclosure 110 and blowing cleaning can be performed
simultaneously.
[0263] Advantageously, the cleaning station 34 is configured for
performing insertion tests with a rod cluster control assembly
(RCCA) and a thimble plug assembly (TPA).
[0264] In this view, as illustrated on FIG. 12, the cleaning
station 34 comprises a lifting tool 150 to which is suspended a
dummy core component 152, i.e. a RCCA or a TPA.
[0265] The lifting tool 150 comprises here a pivoting arm 154 which
can pivot about a vertical pivoting axis B and a hoist which can
slide along the pivoting arm 154 in view of placing the RCCA or TPA
above the fuel assembly 2 received in the cleaning station 34 and
lowering the RCCA or TPA into the fuel assembly 2 or moving the
RCCA or TPA away. The RCCA or TPA can be moved up and down for
example using a hoist for suspending the RCCA or TPA to the
pivoting arm 154.
[0266] As illustrated on FIG. 12, optionally, the cleaning station
34 comprises an elevator 118 for moving an operator vertically
along the fuel assembly 2 placed in the cleaning station 34. This
allows the operator to secure the top nozzle 10 before releasing
the bridge crane 32, to perform the RCCA & TPA tests, to
supervise the cleaning operation and/or to perform a global visual
inspection of the fuel assembly 2. Such visual inspection would not
be possible with a fixed enclosure instead of a telescopic
enclosure 110.
[0267] As visible on FIG. 12, the fuel assembly inspection station
36 is configured for receiving the nuclear fuel assembly 2
vertically.
[0268] The fuel assembly inspection station 36 is configured for
performing geometrical measurements on the fuel assembly 2 which is
received in the fuel assembly inspection station 36. Geometrical
measurements may include length of the fuel assembly 2, verticality
of the fuel assembly 2, distances between fuel rods 4, distances
between fuel rods 4 and guide thimbles 12, twisting of spacer grids
14 and top nozzle 10 about the assembly axis L.
[0269] As illustrated on FIG. 12, the fuel assembly inspection
station 36 comprises a measuring assembly 160 comprising
instruments configured for performing the geometrical measurements,
the measuring assembly 160 being movable vertically along the fuel
assembly 2 received in the fuel assembly inspection station 36,
such as to performed the measurements all along the fuel assembly
2.
[0270] The measuring assembly 160 comprises for example a support
frame 162 of annular shape which in use is fitted around the fuel
assembly 2 and move along the fuel assembly 2, the support frame
162 supporting instruments distributed on the circumference of the
support frame 162.
[0271] The instruments may comprise external probes to contact
external surfaces of the fuel assembly 2 and measure external
geometric parameters (external envelope, twisting, verticality . .
. ) and/or internal probes configured for insertion between the
fuel rods 4 to measure internal geometric parameters (distances
between fuel rods 4, distances between fuel rods 4 and guide
thimbles 12 . . . ).
[0272] The fuel assembly inspection station 36 comprises an
elevator 164 for moving an operator vertically along the fuel
assembly 2 placed in the fuel assembly inspection station 36. This
allows the operator to perform a detailed visual inspection.
[0273] Optionally, the inspection station 36 is configured such
that the fuel assembly 2 received in the inspection station 36 is
rotatable around its vertical axis.
[0274] To this end, the inspection station 36 is for example
equipped with a rotary support 168 which permit the operator to
turn manually the fuel assembly 2 around its vertical axis L. This
allows the operator to inspect visually each one of the four side
faces of the fuel assembly 2.
[0275] The support frame 162 is configured to allow rotation of the
fuel assembly around its longitudinal axis L.
[0276] The rotary support 168 is configured to be blocked in a
defined angular position during the geometrical measurements
performed with the instruments supported by the support frame
162.
[0277] In one embodiment, such a rotary feature is not implemented
on the cleaning station 34. The elevator 118 at the cleaning
station 34 allows the operator to make a workmanship review of the
fuel assembly 2 but not a detailed visual inspection on the four
side faces of the fuel assembly as in the inspection station 36.
The elevator 118 of the station 34 is provided primarily for
enabling the operator to secure the top nozzle before releasing the
crane 32 and to perform the RCCA & TPA tests. According to
another aspect, the present disclosure relates to a method of
expanding a plant for manufacturing a nuclear fuel assembly 2
comprising fuel rods 4 arranged in a bundle and a skeleton 6
supporting the fuel rods 4, the plant having a fuel assembly
manufacturing unit 22 comprising a nuclear fuel rod inserting
station 24 configured for insertion of fuel rods 4 into the
skeleton 6 to obtain a fuel assembly 2 and a packaging station 26
configured for packaging the fuel assembly 2 into a fuel assembly
container 28 in view of transportation, wherein said method
includes a step of building at least one additional manufacturing
unit and connecting the additional manufacturing unit to the fuel
assembly manufacturing unit 22.
[0278] The fuel assembly manufacturing unit 22 and the additional
manufacturing unit are built sequentially. The fuel assembly
manufacturing unit 22 is build and operated for a while (e.g.
several months or several years) and then the additional
manufacturing unit is build.
[0279] In the present disclosure, "connecting" manufacturing units
means that the manufacturing units are connected such as to delimit
together a confined area for the manufacture of nuclear fuel
assemblies. The flow of material between the manufacturing units is
operated in a continuous confined area, in particular without
passing via the exterior to the open air.
[0280] According to one aspect, the method comprises adding an
additional manufacturing unit configured for manufacturing
components to be used in existing manufacturing unit(s) of the
plant, in particular components to be used in the fuel assembly
manufacturing unit 22. These components have to be manufactured
before performing the process steps performed in the already
existing manufacturing units, in particular in the fuel assembly
manufacturing unit 22.
[0281] Hence, the plant is expanded in the upstream way when
considering the process of manufacturing a nuclear fuel assembly
2.
[0282] In a particular embodiment, an additional manufacturing unit
is a fuel rod manufacturing unit 70 configured for manufacturing
fuel rods 4 starting from pellets. These fuel rods 4 can thus be
used in an inserting step performed in the inserting station 24 of
the fuel assembly manufacturing unit 22.
[0283] Further additional manufacturing units may be
contemplated.
[0284] In one embodiment, the method includes a step of adding a
fuel pellet manufacturing unit configured for manufacturing
UO.sub.2 based nuclear fuel pellets and connecting the fuel pellet
manufacturing unit to the fuel rod manufacturing unit 70.
[0285] The method may also include a step of adding a fuel powder
manufacturing unit configured for converting a nuclear fuel
precursor into nuclear fuel powder, e.g. gaseous UF.sub.6 into
UO.sub.2 powder, and connecting the fuel powder manufacturing unit
to the fuel pellet manufacturing unit.
[0286] In one embodiment, the method includes a step of adding a
skeleton manufacturing unit configured for receiving separate
skeleton parts and assembling the skeleton parts into skeleton
6.
[0287] In one embodiment, the method includes a step of adding a
pre-plugged cladding tube manufacturing unit configured for the
manufacturing of cladding tubes having one plug welded at one end
of the cladding tube. Such a pre-plugged cladding tube may be used
directly in the fuel rod loading station 80.
[0288] Each additional manufacturing unit may be located in the
same building as an existing manufacturing unit or may be located
in a new building that is connected to the building(s) of the
existing the manufacturing unit(s).
[0289] In one embodiment, skeleton manufacturing unit and/or a
pre-plugged cladding tube manufacturing unit is/are added to an
existing nuclear fuel assembly manufacturing plant 20 comprising a
fuel assembly manufacturing unit 22 and/or a fuel rod manufacturing
unit 70, with each being located in the same building as the fuel
assembly manufacturing unit 22 or in the same building as the fuel
rod manufacturing unit 70.
[0290] For example, the added skeleton manufacturing unit and/or
the added pre-plugged cladding tube manufacturing unit each can be
located at a first floor of a fuel assembly manufacturing unit 22
and/or a fuel rod manufacturing unit 70.
[0291] In one specific example, an added skeleton manufacturing
unit is located at a first floor of an existing fuel assembly
manufacturing unit 22 and/or an added pre-plugged cladding tube
manufacturing unit is located at a first floor of an existing fuel
rod manufacturing unit 70.
[0292] In a specific embodiment, as illustrated on FIG. 13, the
method comprises sequentially building a fuel assembly
manufacturing unit 22, then adding a fuel rod manufacturing unit 70
to the existing fuel assembly manufacturing unit 22, then,
optionally, adding a fuel pellet manufacturing unit 170 and then,
optionally, adding a fuel powder manufacturing unit 172. Each
addition is performed after operation the existing manufacturing
unit(s) for a while, typically several months or several years.
[0293] According to one aspect, the method comprises adding an
additional manufacturing unit which is a manufacturing unit of the
same type as an existing manufacturing unit of the plant, i.e. a
manufacturing unit configured for performing the same manufacturing
steps.
[0294] In one embodiment, the additional manufacturing unit is a
fuel assembly manufacturing unit 22 added to an existing fuel
assembly manufacturing unit 22 for increasing production
capacity.
[0295] In one embodiment the method includes a step of building an
additional fuel pellet manufacturing unit 170 configured for
manufacturing UO.sub.2 based nuclear fuel pellets and connecting
the additional fuel pellet manufacturing unit 170 to the additional
fuel rod manufacturing unit 70.
[0296] Optionally, the method includes a step of building an
additional fuel powder manufacturing unit 172 configured for
converting UF.sub.6 into UO.sub.2 and connecting the additional
fuel powder manufacturing unit to the additional fuel pellet
manufacturing unit 170.
[0297] The method of expanding a nuclear fuel assembly
manufacturing plant 20 avoids investing immediately in a complete
nuclear fuel assembly manufacturing plant 20 including the fuel rod
manufacturing unit 70, and thus makes the starting investment
easier. In addition, this allows gaining knowledge of the fuel
assembly assembling before stepping to the fuel rod manufacturing
starting from pellets which is more delicate.
[0298] Advantageously, complementary manufacturing units (fuel
assembly manufacturing unit 22, fuel rod manufacturing unit 70,
fuel pellet manufacturing unit 170 and fuel powder manufacturing
unit 172) are aligned in an alignment direction A and manufacturing
units of the same type (e.g. two fuel assembly manufacturing units
22) are placed side-by-side in the transverse direction T.
[0299] In addition, each pair of manufacturing units of the same
type are preferably arranged symmetrically with respect to a
vertical median plan S located between the two manufacturing units,
in terms of location of their respective stations. The vertical
median plan S extends vertically and along the alignment direction
A.
[0300] In the example illustrated on FIGS. 14 and 15, the nuclear
fuel assembly manufacturing plant 20 comprises two fuel assembly
manufacturing units 22 and two fuel rod manufacturing units 70. The
two fuel assembly manufacturing units 22 are located side-by-side
in the transverse direction T. Each fuel rod manufacturing unit 70
is aligned with a respective fuel assembly manufacturing unit 22 in
the alignment direction A.
[0301] The manufacturing units are located in a 2.times.2 matrix
pattern.
[0302] The two fuel assembly manufacturing units 22 are configured
symmetrically with respect to a vertical median plan S, in terms of
disposition of their respective stations. The two fuel rod
manufacturing units 70 are configured symmetrically with respect to
the vertical median plan S, in terms of disposition of their
respective stations.
[0303] According to one aspect of the present disclosure, e.g. for
allowing to implement the method of expanding the nuclear fuel
assembly manufacturing plant 20, this latter is of modular
construction.
[0304] The nuclear fuel assembly manufacturing plant 20 is for
example configured for sequentially adding manufacturing units of
different types for performing different steps of the manufacture
of a fuel assembly 2 (fuel assembly manufacturing unit 22, fuel rod
manufacturing unit 70 . . . ).
[0305] The nuclear fuel assembly manufacturing plant 20 is
configured for connecting the manufacturing units of different
types in the alignment direction A, whereby the nuclear fuel
assembly manufacturing plant 20 can be expanded with adding
complementary manufacturing units (fuel rod manufacturing unit 70,
fuel pellet manufacturing unit 170 and fuel powder manufacturing
unit 172) in the alignment direction A.
[0306] The nuclear fuel assembly manufacturing plant 20 illustrated
on FIGS. 4 and 5 comprises a fuel assembly manufacturing unit 22
and a fuel rod manufacturing unit 70 and could be expanded by
adding a fuel pellet manufacturing unit and optionally a fuel
powder manufacturing unit.
[0307] Each manufacturing unit (fuel assembly manufacturing unit,
fuel rod manufacturing unit . . . ) comprises utility systems each
configured to provide a utility necessary for implementation of the
method and the operation of the plant.
[0308] The utility systems of each manufacturing unit may include
one or several among the following: an electric supply system, a
computer network, a heating, ventilating and air conditioning
system, a gaz supply system, a water supply network, a wastewater
network, a compressed air supply system, a process ventilation
system, an airborne contamination surveillance system, a
criticality alarm system, a fire sections and doors system, a fire
detector and alarm system.
[0309] Each manufacturing unit may comprise at least one utility
system configured for interconnection with corresponding utility
system of another manufacturing unit connected to said
manufacturing unit and/or at least one utility system configured to
operate independently from the corresponding utility system of
another manufacturing unit connected to said manufacturing
unit.
[0310] In one exemplary embodiment, at least one or each utility
system of each manufacturing unit is natively configured for
interconnection with a corresponding utility system of an upstream
manufacturing unit that may potentially be constructed later
side-by-side with the manufacturing unit.
[0311] Besides, each manufacturing unit is provided for
interconnection with an additional manufacturing unit with
delimiting a confined area.
[0312] Alternatively, at least one or each utility system of each
manufacturing unit is independent from the corresponding utility
system of each other manufacturing unit. This allows providing
rightsized utility systems and thus limits the investment for the
building of a manufacturing unit.
[0313] In a specific embodiment, each manufacturing unit comprises
at least one utility system configured for interconnection with
corresponding utility system of each other manufacturing unit and
at least one utility configured to be independent from the
corresponding utility system of each other manufacturing unit.
[0314] In such case, the utility system configured for
interconnection is for example an alarm system, which is useful for
propagating an alarm in all the manufacturing units or a computer
network which is useful e.g. for transmission of information
between manufacturing units, e.g. for traceability of the fuel
assembly component during the manufacture of the fuel assembly.
[0315] In the example of FIGS. 4 and 5, the fuel assembly
manufacturing unit 22 and the fuel rod manufacturing unit 70 are
arranged side-by-side. The fuel assembly manufacturing unit 22 is
configured for connecting a fuel rod manufacturing unit 70 on a
side of the fuel assembly manufacturing unit 22.
[0316] The fuel assembly manufacturing unit 22 and the fuel rod
manufacturing unit 70 each comprise utility systems
[0317] When constructed alone, each utility system of the fuel
assembly manufacturing unit 22 is natively configured for
connection with a corresponding utility system of the fuel rod
manufacturing unit 70 that may potentially be constructed later
side-by-side with the fuel assembly manufacturing unit 22.
[0318] Besides, the fuel assembly manufacturing unit 22 is provided
for interconnection with the fuel rod manufacturing unit 70 as
regards the path of the fuel rods 4.
[0319] Indeed, as it is visible on FIG. 5, the final step of the
nuclear fuel rod production is performed in the fuel rod inspection
area 84 which is adjacent to the inserting station 24. The fuel
rods 4 can thus be transferred from the fuel rod inspection area 84
to the inserting station 24 easily, here via the second conveying
system 106.
[0320] Advantageously, the nuclear fuel assembly manufacturing
plant 20 comprising a fuel assembly manufacturing unit 22 and a
fuel rod manufacturing unit 70 is housed in a building made of
several building modules, the fuel assembly manufacturing unit 22
and the fuel rod manufacturing unit 70 being housed in respective
building module(s).
[0321] In other words, the fuel assembly manufacturing unit 22 is
received in one or several building module(s) of the building which
are distinct from the building module(s) receiving the fuel rod
manufacturing unit 70.
[0322] In a more general manner, advantageously, a nuclear fuel
assembly manufacturing plant comprising a first manufacturing unit
and a second manufacturing different from one another and
configured for performing two distinct steps is housed in a
building made of building modules, the first manufacturing unit
being housed in one or several building module(s) distinct from
building module(s) receiving the second manufacturing unit.
[0323] This allows constructing the manufacturing units
sequentially, e.g. with constructing and operating a first
manufacturing unit before adding the second manufacturing unit to
the fuel assembly manufacturing plant. The different aspects of the
present disclosure are advantageous independently from each other.
In addition, the specific features of the stations of the
manufacturing unit are also advantageous independently from the
manufacturing method and plant.
[0324] For example, the specific features of the pellet inspection
area, the outgassing station, the fuel rod loading station, the
welding station, the fuel rod inspection area, the fuel assembly
cleaning station and/or the fuel assembly inspection station are
advantageous in isolation or in combination. Hence the present
disclosure relates in a general manner to a fuel assembly
inspection station configured for inspection of the fuel assembly
positioned in a vertical position and/or comprising an elevator for
an operator.
[0325] Besides, the present disclosure also relates in a general
manner to a fuel assembly cleaning station configured for
inspection of the fuel assembly positioned in a vertical position
and/or comprising an elevator for an operator and/or comprising a
telescopic enclosure.
[0326] The present disclosure still relates in a general manner to
a fuel rod conveying assembly comprising a fuel rod first conveying
system extending in a first direction, a fuel rod second conveying
extending in a second direction making a non-zero angle with the
first direction, and a pivot trolley for transferring fuel rods
from the first conveying system to the second conveying system.
* * * * *