U.S. patent application number 10/715071 was filed with the patent office on 2005-05-19 for measuring head and measuring assembly for a nuclear fuel rod.
Invention is credited to Busch, Alexander, Dittkuhn, Klaus, Schumann, Rainer, Zuleger, Jurgen.
Application Number | 20050104586 10/715071 |
Document ID | / |
Family ID | 34575287 |
Filed Date | 2005-05-19 |
United States Patent
Application |
20050104586 |
Kind Code |
A1 |
Busch, Alexander ; et
al. |
May 19, 2005 |
MEASURING HEAD AND MEASURING ASSEMBLY FOR A NUCLEAR FUEL ROD
Abstract
A measuring head is used in measuring an assembly part of a
nuclear facility, such as a fuel rod, a fuel assembly box, or a
spacer of the fuel assembly. The measuring head is capable of
augmenting a comparatively large data base representing the overall
aging state of the fuel elements in a simple manner and within a
short measuring time. The measuring head has a probe tip on the
sensor housing and a layer thickness measuring probe is integrated
into said probe housing, said measuring probe working according to
the eddy current principle. The contour or the diameter of the fuel
rod can be determined by the measured deflection of the probe.
Inventors: |
Busch, Alexander; (Erlangen,
DE) ; Zuleger, Jurgen; (Langensendelbach, DE)
; Dittkuhn, Klaus; (Hemhofen, DE) ; Schumann,
Rainer; (Erlangen, DE) |
Correspondence
Address: |
LERNER AND GREENBERG, PA
P O BOX 2480
HOLLYWOOD
FL
33022-2480
US
|
Family ID: |
34575287 |
Appl. No.: |
10/715071 |
Filed: |
November 17, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10715071 |
Nov 17, 2003 |
|
|
|
PCT/EP02/05217 |
May 13, 2002 |
|
|
|
Current U.S.
Class: |
324/240 |
Current CPC
Class: |
G01B 7/20 20130101; G01B
7/105 20130101; G21C 17/06 20130101; Y02E 30/30 20130101 |
Class at
Publication: |
324/240 |
International
Class: |
G01N 027/82; G21C
017/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2001 |
DE |
101 23 975.0 |
Claims
1. A fuel rod testing assembly, comprising: a plurality of
measuring devices each having a sensing arm with a laterally
deflectable free end and a measuring head carried on said free end
of said sensing arm; and a carrier body carrying said plurality of
said measuring devices and being mounted on a plurality of guide
rolls disposed to be guided along a fuel rod; said measuring head
of said measuring device having: a sensor housing; a sensing tip
for determining a contour or geometry characteristic value of the
fuel rod, said sensing tip being disposed on said sensor housing;
and a layer thickness measuring probe integrated in said sensor
housing for measuring a thickness of a layer on the fuel rod.
2. The fuel rod testing assembly according to claim 1, wherein said
layer thickness measuring probe comprises a coil arrangement
connected to an eddy current detector.
3. The fuel rod testing assembly according to claim 1, wherein said
layer thickness measuring probe is disposed inside said sensor
housing, behind said sensing tip.
4. The fuel rod testing assembly according to claim 1, wherein said
sensing tip is made from diamond.
5. The fuel rod testing assembly according to claim 1, wherein said
sensing arm is disposed on said carrier body via a bending joint,
and a sensor is disposed for recording a bending angle of said
bending joint.
6. The fuel rod testing assembly according to claim 1, wherein said
sensing arm is a deflectable spring steel sheet.
7. The fuel rod testing assembly according to claim 1, which
further comprises a strain gauge disposed on said sensing arm.
8. The fuel rod testing assembly according to claim 1 configured
for testing any of a number structural parts of a nuclear
engineering installation.
9. The fuel rod testing assembly according to claim 8 configured
for testing a fuel rod, a fuel assembly channel, or a spacer of the
nuclear engineering installation.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of copending
International Application No. PCT/EP02/05217, filed May 13, 2002,
which designated the United States and which was not published in
English.
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0002] The invention relates to a measuring head, in particular for
use in the measurement of a fuel rod of a fuel assembly and/or a
spacer in a fuel assembly of a nuclear engineering installation.
The invention also relates to a measuring device having a measuring
head of this type and to the implementation of a measuring device
of the type.
[0003] To generate electrical energy in a nuclear installation, in
particular in a nuclear power plant, it is customary for fissile
material to be subjected to controlled nuclear fission. The fissile
material is held in a number of fuel rods, in which the material,
for example in the form of pellets, is surrounded by suitable
cladding tubes. A plurality of fuel rods of this type are usually
combined to form a fuel assembly. It is thereby ensured, even in
long-term operation of the nuclear engineering installation, that a
predetermined geometry is maintained and in particular that
specified distances between the fuel rods of a fuel assembly are
maintained by means of suitable spacers.
[0004] When a nuclear engineering installation of this type is
operating, the respective components or installed parts are subject
to ageing processes, such as for example corrosion. Furthermore,
components of this type are also exposed to radioactive radiation
over a prolonged period of time, which may in addition to the
standard ageing-induced corrosion or fatigue effects also lead to
changes in shape or dimensions. This may in turn have an adverse
effect on the performance or reliability of the component in
question. Particularly when using fuel rods, ageing-induced effects
of this type can lead to the phenomenon known as creep, in which
the fuel rod in question changes, inter alia, its diameter.
Furthermore, however, it is also possible for oxidation to occur at
the surface of a fuel rod, as a type of corrosion, which may lead
to the formation of a more or less continuous oxide layer on the
surface of the fuel rod. Depending on the thickness of the oxide
layer which forms, the wall thickness of the cladding tube below
may be adversely affected, even to such an extent that it drops
below a limit wall thickness which is still classified as
acceptable for the fuel rod to continue to operate. Both effects,
i.e. the changes in shape or dimensions, on the one hand, and the
formation of oxide layers, on the other hand, may therefore
together or even individually cause the reliability and correct
functioning of the fuel rod in question to be adversely
affected.
[0005] For this reason, as part of regular maintenance, it is
customary to test installed parts in a nuclear engineering
installation for the occurrence of such effects. In this context,
the term "installed part" is to be understood as meaning in
particular a fuel rod, a fuel assembly channel, a spacer or some
other structural part in the nuclear engineering installation. When
carrying out a check of this type, on the one hand a measurement is
carried out on a random sample of the installed parts to determine
whether a significant change has occurred in the fuel rod diameter,
also, the corresponding installed parts are subjected to a random
sample measurement to check for changes in shape and dimensions.
Specially produced sensors, which can be used to acquire sample
measurement data for selected installed parts, in particular
selected fuel rods, can be used for these maintenance and test
measurements.
[0006] Independently of this, on the other hand, a sample
examination is carried out on the installed parts at regular
maintenance intervals to determine whether and to what extent oxide
layers have formed. These measurement results are used to draw
conclusions as to the ageing state of these components, it being
possible in particular to replace some or all of the fuel rods as
required. Specifically designed measuring devices, in which a
suitable measuring probe is used to determine measurement data
concerning the layer thickness of the oxide layer on selected fuel
rods or other installed parts, are likewise employed to determine
the corresponding measurement data.
[0007] However, it is still a relatively complex matter to
determine information concerning the ageing state of the
corresponding installed part, in particular the fuel rods or
spacers, in this way. In particular, the above-mentioned
measurements may entail down times in the nuclear engineering
installation, and such down times need to be kept particularly
short if only for economic reasons. To maintain relatively short
down times, it may be necessary for the sample measurements to be
restricted to a relatively small number of the components which are
to be measured, in particular fuel rods or spacers, and
consequently the database available for reliable assessment is
relatively small. This in turn may lead to unacceptable inaccuracy
when determining the state of the fuel elements and in particular
forecasting the future ageing-induced performance of the fuel
assemblies.
SUMMARY OF THE INVENTION
[0008] It is accordingly an object of the invention to provide a
measuring head, which overcomes the above-mentioned disadvantages
of the heretofore-known devices and methods of this general type
and which is particularly suited for use in the measurement of an
installed part of the above type, for example of a fuel rod of a
fuel assembly channel and/or a spacer, in a fuel assembly of a
nuclear engineering installation, which makes it possible, in a
particularly simple way and within a short measuring time, to build
up a relatively large database which overall is representative of
the ageing state of the fuel assemblies. Moreover, it is intended
to provide a measuring device which is particularly suitable for
use in measuring an installed part of this type, in particular a
fuel rod and/or spacer.
[0009] With the foregoing and other objects in view there is
provided, in accordance with the invention, a fuel rod testing
assembly, comprising:
[0010] a plurality of measuring devices each having a sensing arm
with a laterally deflectable free end;
[0011] a measuring head carried on the free end of the sensing arm,
the measuring head having a sensor housing and a sensing tip
disposed on the sensor housing;
[0012] a layer thickness measuring probe integrated in the sensor
housing for measuring a thickness of a layer on a fuel rod; and
[0013] a carrier body carrying the measuring devices and being
mounted on a plurality of guide rolls disposed to be guided along
the fuel rod.
[0014] In other words, the objects of the invention concerning the
measuring head are achieved by a sensing tip which is arranged on a
sensor housing, and with a layer thickness measuring probe
integrated into the sensor housing.
[0015] In this context, the invention is based on the consideration
that particularly effective data acquisition, which is therefore
favorable in terms of the length of time required, is made possible
when determining the ageing state of the installed part in question
by virtue of the fact that a combined determination of various
measured values is carried out. For this purpose, the measuring
head is equipped, in a combined design, with various types of
measuring probes which allow various types of data to be determined
simultaneously on the installed part which is to be examined. The
measuring probes are designed to record the data which is of
relevance to the desired information concerning the ageing state of
the installed part, having a sensing tip which can be guided in
mechanical contact along the surface of the object to be examined
in each case for determination purposes, on the one hand, and a
measuring probe for determining the layer thickness of an oxide
layer, on the other hand.
[0016] To allow reliable determination of the thickness of the
oxide layer using relatively simple means, the layer thickness
measuring probe advantageously comprises a coil arrangement
connected to an eddy current measuring appliance. The layer
thickness measuring probe which includes the coil arrangement is in
this case designed in particular to determine the thickness of a
layer which is not electrically conductive--specifically in the
present case the oxide layer--using what is known as the "lift-off
effect." When exploiting this effect, the change in impedance in
the coil as a function of the change in the distance of the coil
arrangement from an electrically conductive measurement object is
employed. The electrically conductive measurement object used in
this case is the metallic tubular cladding of the fuel rod or the
metallic base material of the respective fuel assembly channel,
spacer or other structural part. The distance between the base
material and the coil is in this case given on the one hand by the
(constant) distance between the coil arrangement and the front edge
of the sensing tip guided along the surface of the oxide layer and
on the other hand by the layer thickness of the oxide layer itself
which is to be determined. The coil arrangement, which is operated
at high frequency, in this case generates an eddy current in the
base material or in the tubular cladding which is used as the
electrically conductive measurement object, and this eddy current
in turn has an effect on the impedance of the coil as a function of
the distance.
[0017] In a particularly advantageous configuration, the layer
thickness measurement probe is disposed inside the sensor housing
behind the sensing tip. With a configuration of this type, in which
the symmetry or central line of the sensing tip is preferably
congruent with that of the coil arrangement, the geometric
conditions allow particularly unambiguous determination of the
distance from the coil arrangement to the tip of the sensing
needle, so that the sum which remains when determining the distance
from the coil arrangement to the electrically conductive
measurement object can be particularly reliably assigned to the
layer thickness of the oxide layer. Furthermore, a configuration of
this type also allows cumulative determination of data both for the
contour profile via the sensing tip and for the profile of the
layer thickness of the oxide layer via the coil arrangement on a
common measurement line, so that two sets of measurement data are
present for a single local partial area of the corresponding fuel
rod or spacer. This also allows the measurement data to be
evaluated with a view to a possible correlation between the
measured diameter or geometry changes and the measured layer
thickness of the oxide layer. Particularly reliable conclusions as
to the ageing-induced state of the installed part in question can
be achieved in particular on the basis of a combined assessment of
this nature.
[0018] For particularly reliable measurement of the contour
parameter or profile, the sensing tip is advantageously made from
diamond, in which case in particular the relatively high hardness
of this material produces favorable wear properties for the sensing
tip.
[0019] With regard to the measuring device which is particularly
suitable for measuring a fuel rod, a fuel assembly channel or a
spacer, the above object is achieved by a sensing arm which is
arranged on a carrier body and, at a free, laterally deflectable
end, bears a measuring head of the above type. A measuring device
of this type allows combined and therefore simultaneous measurement
of a contour parameter, on the one hand, and the thickness of an
oxide layer, on the other hand, in a particularly simple way. In
this case, the measuring device is configured in such a manner that
the sensing tip of the measuring head can be guided along the
object which is to be examined in mechanical contact therewith. A
measured value which is characteristic of the contour of the object
to be examined can in this case be determined on the basis of the
deflection of the sensing arm, while at the same time the layer
thickness measuring probe which is integrated in the measuring head
supplies a measured value for the thickness of the oxide layer at
exactly the same location.
[0020] In this context, reliable determination of the deflection of
the sensing arm can be achieved in a particularly simple way if the
sensing arm is advantageously mounted on the carrier body via a
bending joint which is assigned a sensor for recording its bending
angle. On account of the geometric conditions, a characteristic
value for the corresponding lateral deflection of the measuring
head can be derived unambiguously from the bending angle.
[0021] The measuring device can be produced with particularly
little outlay, in particular on materials, if the sensing arm is
advantageously configured as a deflectable spring steel sheet.
[0022] In a particularly advantageous refinement, a strain gauge is
arranged on the sensing arm of the measuring device. In this case,
a measurement signal which is characteristic of the lateral
expansion of the surface of the sensing arm can be provided via the
strain gauge with a relatively high accuracy. This allows a
reliable conclusion to be drawn as to the corresponding deflection
of the sensing arm at its free end with a particularly high
resolution. Particularly in combination with the bending joint
whose bending angle can be recorded, combined fine and coarse
measurement of the deflection of the sensing arm can in this case
be achieved, which on the one hand allows a relatively
high-resolution measurement with a wide measuring range or on the
other hand a redundant and therefore particularly exact measurement
of the deflection within a relatively small measuring range.
[0023] In a particularly advantageous configuration, a number of
measuring devices of this type are used in a fuel rod testing
assembly or in a testing assembly for a fuel assembly channel or a
spacer of a fuel assembly. In this case, a number of measuring
devices of this type are expediently provided in a fuel rod testing
assembly, in which case a carrier body which is common to the
measuring devices is mounted on a number of guide rolls which can
be guided along a fuel rod.
[0024] The advantages which are achieved by the invention consist
in particular in the fact that the combined provision of suitable
measuring means both for determining a contour parameter, for
example as a basis for the determination of a diameter
characteristic value, and for the determination of a measured value
for the thickness of the oxide layer allows simultaneous
measurement of these parameters, and moreover still represents the
same spatial area of the measurement object. The outlay on time and
logistics required to carry out the measurements which are
necessary in order to characterize a fuel rod or spacer is
therefore kept particularly low. Consequently, it is possible to
provide a particularly extensive set of data, which is therefore
particularly characteristic of the general state of the components
examined, even with relatively little intervention into the
operating sequence of the nuclear engineering installation and in
particular also in a relatively short measurement time.
Furthermore, only a single generic type of measuring devices are
required to provide the complete set of data, and consequently the
logistical outlay and in particular the stock management of spare
parts for these devices are kept particularly simple. Particularly
with the coil arrangement arranged directly behind the sensing tip,
moreover, the data are determined on a track or line, so that
correlations between the contour and the thickness of the oxide
layer can be taken into account in the analysis in a particularly
simple way.
[0025] Other features which are considered as characteristic for
the invention are set forth in the appended claims.
[0026] Although the invention is illustrated and described herein
as embodied in a measuring head, it is nevertheless not intended to
be limited to the details shown, since various modifications and
structural changes may be made therein without departing from the
spirit of the invention and within the scope and range of
equivalents of the claims.
[0027] The construction and method of operation of the invention,
however, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 side view of a section taken through a measuring head
disposed on a sensing arm;
[0029] FIG. 2 is a diagrammatic illustration of a side view of a
fuel rod testing assembly;
[0030] FIG. 3 is a diagrammatic plan view of the fuel rod testing
assembly of FIG. 2; and
[0031] FIG. 4 is a diagrammatic plan view of a measuring device for
a spacer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Referring now to the figures of the drawing in detail and
first, particularly, to FIG. 1 thereof, there is shown a measuring
head 1 for measuring an installed part, in particular a fuel rod of
a fuel assembly channel or a spacer of a fuel assembly, in a
nuclear engineering installation. The measuring head 1 is designed
in such a manner that it is possible both to determine a contour or
geometry characteristic value of an object to be examined, i.e., of
the workpiece, and to determine the thickness of an oxide layer on
the surface of the object which is to be examined simultaneously
and in one measuring operation, in the manner of a combined
measurement.
[0033] To determine a contour or geometry characteristic value, the
measuring head 1 comprises a sensor housing 2 on which a sensing
tip 4 is disposed. The sensing tip 4 is made from diamond, but may
also be in multi-component form using a material with a suitably
selected hardness. To determine a contour or geometry
characteristic value of an object 7, which may in particular be a
fuel rod or a spacer in a fuel assembly, the sensing tip 4 can be
guided along the object, in mechanical contact therewith. Any
change in the contour or geometry at the surface of the object to
be examined results in a change in the position of the sensing tip
4 and therefore the measuring head 1 overall, in the direction x
indicated by the double arrow 8. To provide a characteristic
measured value for a change in position of this nature, the
measuring head 1 is arranged at the free end 10 of a sensing arm
12. For its part, the sensing arm 12 is suitably secured to a
carrier device at its other end, which is not illustrated in more
detail in FIG. 1. In the exemplary embodiment shown in FIG. 1, the
sensing arm 12 is made from spring steel sheet. In this case, a
deflection of the free end 10 of the sensing arm 12 as a result of
a change in position of the measuring head 1 in the measuring
direction x leads to bending or deformation of the spring steel
sheet. This can be recorded quantitatively by way of a strain gauge
14 mounted on the surface of the sensing arm 12. Therefore, an
assembly of this type makes it possible to record even relatively
minor changes in the position of the measuring head 1 in the
direction x with a high resolution.
[0034] As an alternative, or in addition, the sensing arm 12 may
also be provided with a bending joint, the bending angle of which
can be recorded using a suitable bending angle sensor. In that
case, the position of the measuring head 1 in direction x can be
determined by combined analysis of measured values of the strain
gauge 14 and the bending angle sensor.
[0035] The measuring head 1 which is in this way suitable for
providing a contour or geometry characteristic value is furthermore
also configured to measure the thickness of an oxide layer 20 on
the surface of an object 7 to be examined, carried by a metallic
base material 22 of the object 7. For this purpose, a layer
thickness measuring probe 30 is integrated in the sensor housing 2
of the measuring head 1. The layer thickness measuring probe 30
comprises a coil arrangement 32, which is connected, via signal
lines 34 guided through the sensor housing 2 and through the
sensing arm 12, to an eddy current detector 15. The coil
arrangement 32 is cast into a carrier sleeve 38 by way of a potting
compound 36, and the sleeve 38 is in turn secured in the sensor
housing 2. The coil arrangement 32 is positioned in such a manner
that its symmetry or center line is congruent with that of the
sensing tip 4. Therefore, the layer thickness measuring probe 30 is
disposed inside the sensor housing 2 behind the sensing tip 4.
[0036] The layer thickness measuring probe 30 is configured to
determine the thickness of the oxide layer 20 on the basis of what
is known as "lift-off effect." For this purpose, the coil
arrangement 32 for supplying an eddy current detector is connected
on the input side to a high-frequency generator via a Wheatstone
bridge circuit. The output-side part of the bridge circuit is
connected to an eddy-current measuring assembly by way of a
transmitter. To determine the layer thickness of the oxide layer
20, the coil arrangement 32 is moved into a defined position close
to the oxide layer 20. The defined position of the coil arrangement
32 with respect to the oxide layer 20 is in this case ensured by
virtue of the fact that the coil arrangement 32, on account of its
fixed installation in the sensor housing 2, adopts a defined and
constant distance from the front edge of the sensing tip 4. The
sensing tip 4 in turn--not least in order to carry out the contour
measurement--is brought into direct physical contact with the
surface of the oxide layer 20, and consequently exact positioning
of the coil arrangement 32 with respect to the surface of the oxide
layer 20 is automatically ensured.
[0037] When measuring the layer thickness of the oxide layer 20,
the coil arrangement 32 is fed with a high-frequency input signal.
The magnetic field generated by the coil arrangement 32 operated in
this way produces an eddy current in the metallic base material 22
of the object 7 that bears the oxide layer 20. The resulting eddy
current in turn affects the impedance of the coil arrangement 32.
The level of this effect is dependent on the distance of the
metallic carrier layer 22 from the coil arrangement 32. For its
part, this distance is given by the sum of the distance of the coil
arrangement 32 from the front edge of the sensing tip 4 and the
thickness of the oxide layer 20. The bridge circuit used to operate
the coil arrangement 32 therefore supplies as its output signal a
voltage signal which for its part is characteristic of the
thickness of the oxide layer 20 and can therefore be evaluated to
provide the latter.
[0038] The measuring head 1 is therefore suitable for the
simultaneous determination of the contour, on the one hand, and the
thickness of a surface oxide layer 20 of the object 7 to be
examined, on the other hand. Therefore, the measuring head 1 can
particularly advantageously be used for time-saving measurement of
installed parts, in particular of fuel rods, fuel assembly
channels, spacers or other structural parts in a nuclear
engineering installation in order to allow reliable estimation of
their ageing state or expected remaining service life. For this
purpose, the measuring head 1, as shown diagrammatically and in
side view in FIG. 2 and in plan view in FIG. 3, can be used in a
measuring device 50 which for its part in turn forms part of a fuel
rod testing assembly 52. The measuring device 50 shown in FIGS. 2
and 3 comprises two sensing arms 12, at the free, laterally
deflectable end 10 of which in each case one of the measuring heads
1 is arranged. In this case, as can be seen in particular from the
plan view shown in FIG. 3, the sensing arms 12 are arranged
opposite one another in the style of a fork and are therefore
suitable for engaging around a fuel rod 54 which is guided between
them and is to be tested. The measuring heads 1 are in this case
arranged opposite one another, so that the fuel rod 54 can be
scanned on both sides. On account of this arrangement of the
measuring heads 1 opposite one another, it is possible to determine
a characteristic value for the diameter of the fuel rod 54.
[0039] The sensing arms 12 are arranged on a common carrier body
56, which for its part is mounted on a number of guide rolls 58
which can be guided along the fuel rod 54. The guide rolls 58 in
each case comprise a central roll body 60 which is delimited on
both sides by in each case one guide disk 62. The guide disks 62
have a greater diameter than the diameter of the roll body 60. A
roll body 60 which rolls along the surface of the fuel rod 54 is
therefore automatically centered with respect to the fuel rod 54
which is to be examined by the guide disks 62 which delimit it.
[0040] The fuel rod testing assembly 52 together with its measuring
device 50 can be moved along the fuel rod 54, in the longitudinal
y-direction of the fuel rod 54 indicated by the double arrow 64, by
means of a drive device. As a result, if necessary the fuel rod 54
can be scanned along its longitudinal direction y. This scanning on
the one hand, in the style of a profile measurement, provides
contour measured values on the basis of the sensing tips 4 of the
measuring heads 1, which in turn can be converted into
position-dependent diameter characteristic values for the fuel rod
54. This scanning in this case takes place along a scanning track
indicated by the line 66. Furthermore, during the scanning, the
layer thickness measuring probes 30 of the measuring heads 1
provide position-dependent characteristic values for the thickness
of an oxide layer which may surround the fuel rod 54. The
corresponding measured values are in this case likewise recorded
along the sensing track 66 directly via the corresponding sensing
tip 4 on the basis of the positioning of the corresponding coil
arrangement 32. Therefore, scanning of the fuel rod 54 which takes
place simultaneously for both relevant parameters in this way
results in a particularly extensive set of data for the fuel rod 54
being provided within a relatively short measuring time, on the one
hand, while on the other hand it is also possible to analyze any
correlations between the local layer thickness of the oxide layer
and the local diameter value of the fuel rod 54 on the basis of the
local correspondence between the respective measurement
parameters.
[0041] Alternatively, the measuring head 1 may also be used in a
measuring device 70 for a spacer 72 of a fuel assembly, as
diagrammatically indicated in plan view in FIG. 4. The measuring
device 70 shown in FIG. 4 in this case likewise comprises two
sensing arms 74, at the free, laterally deflectable end 76 of which
in each case one of the measuring heads 1 is disposed. In this
measuring device 70 too, the sensing arms 74 are arranged opposite
one another in the style of a fork and are therefore suitable for
engaging around the spacer 72 which is guided between them and is
to be tested. The sensing arms 74 of the measuring device 70 are
arranged on a guiding and advancing unit 80 as a common carrier
body with the components thereof which are customarily
provided.
* * * * *