U.S. patent application number 12/569123 was filed with the patent office on 2010-10-07 for power monitoring system.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Tadashi Miyazaki, Naotaka Oda, Hirotaka SAKAI, Toshifumi Sato.
Application Number | 20100254504 12/569123 |
Document ID | / |
Family ID | 42249292 |
Filed Date | 2010-10-07 |
United States Patent
Application |
20100254504 |
Kind Code |
A1 |
SAKAI; Hirotaka ; et
al. |
October 7, 2010 |
Power Monitoring System
Abstract
The power monitoring system has: a local power range monitor
(LPRM) unit that has a plurality of local power channels to obtain
local neutron distribution in a nuclear reactor core; an averaged
power range monitor (APRM) unit that receives power output signals
from the LPRM unit and obtains average output power signal of the
reactor core as a whole; and an oscillation power range monitor
(OPRM) unit that receives the power output signals from the LPRM
unit and monitors power oscillations of the reactor core. The
output signals from the LPRM unit to the APRM unit and the output
signals from the LPRM unit to the OPRM unit are independent.
Inventors: |
SAKAI; Hirotaka; (Tokyo,
JP) ; Oda; Naotaka; (Kanagawa, JP) ; Miyazaki;
Tadashi; (Kanagawa, JP) ; Sato; Toshifumi;
(Tokyo, JP) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
KABUSHIKI KAISHA TOSHIBA
|
Family ID: |
42249292 |
Appl. No.: |
12/569123 |
Filed: |
September 29, 2009 |
Current U.S.
Class: |
376/254 |
Current CPC
Class: |
G21C 17/108 20130101;
Y02E 30/30 20130101 |
Class at
Publication: |
376/254 |
International
Class: |
G21C 17/108 20060101
G21C017/108 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2008 |
JP |
2008-253187 |
Claims
1. A power monitoring system comprising: a local power range
monitoring device that has a plurality of local power channels to
obtain local neutron distribution in a nuclear reactor core; an
averaged power range monitoring device that receives power output
signals from the local power range monitoring device and obtains
average output power signal of the reactor core as a whole; and an
oscillation power range monitoring device including an oscillation
power range monitoring mechanism that receives the power output
signals from the local power range monitoring device and monitors
power oscillations of the reactor core, wherein output signals from
the local power range monitoring device to the averaged power range
monitoring device and output signals from the local power range
monitoring device to the oscillation power range monitoring device
are independent.
2. The power monitoring system according to claim 1, wherein, in
the oscillation power range monitoring mechanism, variables that
are changed according to type of fuel of the reactor core are
formed by a combination of electrical contacts that are so
positioned as not to be operated without stopping the oscillation
power range monitoring mechanism.
3. The power monitoring system according to claim 1, wherein, in
the oscillation power range monitoring mechanism, variables that
are changed according to type of fuel of the reactor core cannot be
changed without stopping the oscillation power range monitoring
mechanism, and are stored in an element whose internal state cannot
be changed by operation of the oscillation power range monitoring
mechanism.
4. The power monitoring system according to claim 1, wherein when
at least one of a plurality of the local power channels of the
local power range monitoring device breaks down, corresponding
local power channel is excluded.
5. The power monitoring system according to claim 1, wherein the
oscillation power range monitoring mechanism has a transmission
section that transmits output signals not having input signals in a
one-way direction, and the transmission section transmits the
output signals to a state display section that displays state of
power oscillations.
6. The power monitoring system according to claim 1, wherein the
oscillation power range monitoring mechanism has a transmission
section that transmits output signals not having input signals in a
one-way direction, and the transmission section transmits the
output signals to a history recording device that records a
predetermined period of time of the past history.
7. The power monitoring system according to claim 6, wherein the
history recording device includes: a determination means that makes
a determination as to whether data is normally received; and a
determination result transmission means that transmits the
determination result of the determination means to the transmission
section, wherein the transmission of data from another oscillation
power range monitoring mechanism to the transmission section is
limited to one-way transmission.
8. The power monitoring system according to claim 6, wherein the
transmission section and the history recording device are
electrically isolated.
9. A power monitoring system comprising: a local power range
monitoring device that has a plurality of local power channels to
obtain local neutron distribution in a nuclear reactor core; an
averaged power range monitoring device that receives power output
signals from the local power range monitoring device and obtains
average output power of the reactor core as a whole; and an
oscillation power range monitoring device including an oscillation
power range monitoring mechanism that receives the power output
signals from the local power range monitoring device and monitors
power oscillations of the reactor core, wherein the averaged power
range monitoring device transmits output signals from the local
power range monitoring device to the oscillation power range
monitoring device with the output not passing through an averaged
power range monitor processing function in the averaged power range
monitoring device.
10. The power monitoring system according to claim 9, wherein, in
the oscillation power range monitoring mechanism, variables that
are changed according to type of fuel of the reactor core are
formed by a combination of electrical contacts that are so
positioned as not to be operated without stopping the oscillation
power range monitoring mechanism.
11. The power monitoring system according to claim 9, wherein, in
the oscillation power range monitoring mechanism, variables that
are changed according to type of fuel of the reactor core cannot be
changed without stopping the oscillation power range monitoring
mechanism, and are stored in an element whose internal state cannot
be changed by operation of the oscillation power range monitoring
mechanism.
12. The power monitoring system according to claim 9, wherein when
at least one of a plurality of the local power channels of the
local power range monitoring device breaks down, corresponding
local power channel is excluded.
13. The power monitoring system according to claim 9, wherein the
oscillation power range monitoring mechanism has a transmission
section that transmits output signals not having input signals in a
one-way direction, and the transmission section transmits the
output signals to a state display section that displays state of
power oscillations.
14. The power monitoring system according to claim 9, wherein the
oscillation power range monitoring mechanism has a transmission
section that transmits output signals not having input signals in a
one-way direction, and the transmission section transmits the
output signals to a history recording device that records a
predetermined period of time of the past history.
15. The power monitoring system according to claim 14, wherein the
history recording device includes: a determination means that makes
a determination as to whether data is normally received; and a
determination result transmission means that transmits the
determination result of the determination means to the transmission
section, wherein the transmission of data from another oscillation
power range monitoring mechanism to the transmission section is
limited to one-way transmission.
16. The power monitoring system according to claim 14, wherein the
transmission section and the history recording device are
electrically isolated.
17. A power monitoring system comprising: a local power range
monitoring device that has a plurality of local power channels to
obtain local neutron distribution in a nuclear reactor core; and an
averaged power range monitoring device that receives power output
signals from the local power range monitoring device and obtains
average output power of the reactor core as a whole, wherein the
averaged power range monitoring device includes an averaged power
range monitor processing mechanism and an oscillation power range
monitoring mechanism, and an input from the local power range
monitoring device to the averaged power range monitor processing
mechanism is independent of an input from the local power range
monitoring device to the oscillation power range monitoring
mechanism.
18. The power monitoring system according to claim 17, wherein, in
the oscillation power range monitoring mechanism, variables that
are changed according to type of fuel of the reactor core are
formed by a combination of electrical contacts that are so
positioned as not to be operated without stopping the oscillation
power range monitoring mechanism.
19. The power monitoring system according to claim 17, wherein, in
the oscillation power range monitoring mechanism, variables that
are changed according to type of fuel of the reactor core cannot be
changed without stopping the oscillation power range monitoring
mechanism, and are stored in an element whose internal state cannot
be changed by operation of the oscillation power range monitoring
mechanism.
20. The power monitoring system according to claim 17, wherein when
at least one of a plurality of the local power channels of the
local power range monitoring device breaks down, corresponding
local power channel is excluded.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefits of
priority from the prior Japanese Patent Application No.
2008-253187, filed in the Japanese Patent Office on Sep. 30, 2008,
the entire content of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a power monitoring system
(or a power range monitor) of a boiling water reactor and
particularly to a power monitoring system that monitors the power
oscillations of a nuclear reactor core.
[0003] In the boiling water reactor (BWR), the output power
alternately falls and rises due to the generation and disappearance
of voids, respectively, which may possibly generate power
oscillations whereby the output power of the nuclear reactor
oscillates and is amplified. The widely known reactor core power
oscillation monitoring method is to continue operation as long as
the soundness of core fuel is secure even in an operating range in
which power oscillations occur, and to detect, when oscillations
occur that could lead to events affecting the soundness of the core
fuel, the oscillations, and safely stop the operation of the
nuclear reactor (See, for example, U.S. Pat. No. 5,174,946, the
entire content of which being incorporated herein by reference).
Also widely known is a reactivity adjustment method that stabilizes
the entire reactor core using the above-described method (See, for
example, U.S. Pat. No. 5,141,710, the entire content of which being
incorporated herein by reference).
[0004] High reliability is required to monitor the power
oscillations of the reactor core in terms of securing the soundness
of the core fuel. However, the problem with the above-described
monitoring of power oscillations is that even though oscillations
that could lead to events affecting the soundness of the core fuel
can be detected when the oscillations occur, necessary measures may
not have been taken to secure the soundness of the fuel.
SUMMARY OF THE INVENTION
[0005] The present invention has been made to solve the
above-described problems. The objective of the present invention is
to provide a power monitoring system that can monitor the power
oscillations of the reactor core and establish high reliability in
securing the soundness of the core fuel.
[0006] In order to achieve the objective, a power monitoring system
according to an aspect of the present invention comprises: a local
power range monitoring device that has a plurality of local power
channels to obtain local neutron distribution in a nuclear reactor
core; an averaged power range monitoring device that receives power
output signals from the local power range monitoring device and
obtains average output power signal of the reactor core as a whole;
and an oscillation power range monitoring device including an
oscillation power range monitoring mechanism that receives the
power output signals from the local power range monitoring device
and monitors power oscillations of the reactor core, wherein output
signals from the local power range monitoring device to the
averaged power range monitoring device and output signals from the
local power range monitoring device to the oscillation power range
monitoring device are independent.
[0007] A power monitoring system according to another aspect of the
present invention comprises: a local power range monitoring device
that has a plurality of local power channels to obtain local
neutron distribution in a nuclear reactor core; an averaged power
range monitoring device that receives power output signals from the
local power range monitoring device and obtains average output
power of the reactor core as a whole; and an oscillation power
range monitoring device including an oscillation power range
monitoring mechanism that receives the power output signals from
the local power range monitoring device and monitors power
oscillations of the reactor core, wherein the averaged power range
monitoring device transmits output signals from the local power
range monitoring device to the oscillation power range monitoring
device with the output not passing through an averaged power range
monitor processing function in the averaged power range monitoring
device.
[0008] A power monitoring system according to yet another aspect of
the present invention comprises: a local power range monitoring
device that has a plurality of local power channels to obtain local
neutron distribution in a nuclear reactor core; and an averaged
power range monitoring device that receives power output signals
from the local power range monitoring device and obtains average
output power of the reactor core as a whole, wherein the averaged
power range monitoring device includes an averaged power range
monitor processing mechanism and an oscillation power range
monitoring mechanism, and an input from the local power range
monitoring device to the averaged power range monitor processing
mechanism is independent of an input from the local power range
monitoring device to the oscillation power range monitoring
mechanism.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The above and other features and advantages of the present
invention will become apparent from the discussion hereinbelow of
specific, illustrative embodiments thereof presented in conjunction
with the accompanying drawings, in which:
[0010] FIG. 1 is a block diagram illustrating the configuration of
a power range monitor according to a first embodiment of the
present invention;
[0011] FIG. 2 is a block diagram illustrating the configuration of
a power range monitor according to a second embodiment of the
present invention;
[0012] FIG. 3 is a block diagram illustrating the configuration of
a power range monitor according to a third embodiment of the
present invention; and
[0013] FIG. 4 is a block diagram illustrating the configuration of
a power range monitor according to a sixth embodiment of the
present invention.
DETAILED DESCRIPTION OF PRESENT INVENTION
[0014] Hereinafter, embodiments of a power monitoring system (a
power range monitor) of the present invention will be described
with reference to the accompanying drawings.
[0015] FIG. 1 is a block diagram illustrating the configuration of
a power range monitor according to a first embodiment of the
present invention.
[0016] As shown in the diagram, a power range monitor (PRM) 13 has:
local power range monitor (LPRM) units 1a and 1b, which are a
plurality of local power range monitoring devices that obtain the
local neutron distribution signals in a nuclear reactor core; an
averaged power range monitor (APRM) unit 2, which is an averaged
power range monitoring device that receives the power output
signals from the LPRM units 1a and 1b and obtains the average
output power of the entire reactor core; and an oscillation power
range monitor (OPRM) unit 3, which is an oscillation power range
monitoring device that receives the power output signals from the
LPRM units 1a and 1b and monitors the power oscillations of the
reactor core.
[0017] The inputting of local power signals to the OPRM unit 3 and
the inputting of local power signals to the APRM unit 2 are
performed by the LPRM units 1a and 1b, respectively, and are
shared.
[0018] Incidentally, a process of monitoring the power oscillations
of the reactor core inside the OPRM unit 3 is referred to as an
OPRM process, and a process of securing the soundness of the core
fuel in the APRM unit 2 is referred to as an APRM process.
[0019] The transmitting of signals from the LPRM units 1a and 1b to
the OPRM unit 3 is limited to one-way transmission from the LPRM
units la and lb to the OPRM unit 3 via output modules 4a and 5a of
the LPRM units 1a and 1b.
[0020] The transmitting of signals from the LPRM units 1a and 1b to
the APRM unit 2 is limited to one-way transmission from the LPRM
units 1a and 1b to the APRM unit 2 via the output modules 4b and 5b
of the LPRM units 1a and 1b.
[0021] The PRM 13 has a function to transmit channel signals of the
LPRM units la and lb as well as the breakdown or exclusion signals
of each channel from the LPRM units 1a and 1b to the OPRM unit
3.
[0022] When a breakdown or exclusion signal of any LPRM channel of
the LPRM units 1a and 1b is generated, the corresponding LPRM
channel is excluded in the arithmetic operation in the OPRM unit 3.
Moreover, when a breakdown and/or exclusion signal of the LPRM
units 1a or 1b themselves is generated, all the LPRM channels as a
whole corresponding to the LPRM unit 1a or 1b are excluded by the
OPRM process.
[0023] According to the present embodiment, the outputting of
signals from the LPRM units 1a and 1b to the OPRM unit 3 and the
outputting of signals to the APRM unit 2 are limited to a one-way
direction and carried out via the different output modules 4a and
5a and output modules 4b and 5b. Therefore, the functional
independence of the OPRM unit 3 and the APRM unit 2 is sufficiently
secured. Thus, the power oscillations of the reactor core can be
monitored; high reliability can be established in terms of securing
the soundness of the core fuel.
[0024] FIG. 2 is a block diagram illustrating the configuration of
a power range monitor according to a second embodiment of the
present invention. The portions that are the same as or similar to
those of FIG. 1 have been denoted by the same reference numerals to
avoid repeating the same description.
[0025] As shown in the diagram, a power range monitor (PRM) 13a
has: LPRM units 1a and 1b, which are the local power range
monitoring devices that obtain the local neutron distribution in a
nuclear reactor core; an APRM unit 2, which receives the power
output signals from the LPRM units 1a and 1b, and obtains the
average output power of the entire reactor core; and an OPRM unit
3, which receives from the APRM unit 2 the power output signals
from the LPRM units 1a and 1b and monitors the power oscillations
of the reactor core.
[0026] The inputting of local power signals to the OPRM unit 3 and
the inputting of local power signals to the APRM unit 2 are
performed by the LPRM units 1a and 1b, respectively, and are
shared.
[0027] The CPRM unit 3 and the APRM unit 2 have separate
reactor-core monitoring functions, and the function of the OPRM
unit 3 is formed independently of the function of the APRM unit
2.
[0028] The APRM unit 2 includes: an LPRM signal receiving section
6, which receives LPRM signals; an LPRM signal transmitting section
7, which transmits the LPRM signals to the CPRM unit 3; and an APRM
processing section 8, which orders the APRM unit 2 to perform a
necessary process.
[0029] In the APRM unit 2, once the LPRM signal receiving section 6
receives the LPRM signals from the LPRM units 1a and 1b, the
received signals are transmitted to the LPRM signal transmitting
section 7 and the APRM processing section 8. In the OPRM unit 3,
the LPRM signals are received through the LPRM signal transmitting
section 7 of the APRM unit 2.
[0030] Incidentally, the PRM 13a has a function to transmit the
breakdown or exclusion signals of any of LPRM channels and of the
LPRM units 1a or 1b from the LPRM units 1a and 1b to the APRM unit
2. Moreover, the signals are designed to be transmitted to the OPRM
unit 3.
[0031] When a breakdown or exclusion signal of any LPRM channels
and of the LPRM units 1a and 1b is generated, the corresponding
LPRM channel is excluded by an arithmetic operation in the OPRM
unit 3. Moreover, when a breakdown or exclusion signal of the LPRM
unit 1a or 1b is generated, all the LPRM channels corresponding to
the LPRM unit 1a or 1b are excluded by the OPRM process.
[0032] According to the present embodiment, in the OPRM unit 3, the
LPRM signals are received via the APRM unit 2. However, the LPRM
signals do not pass through the APRM processing section 8 that
performs an APRM process when the LPRM signals are transmitted.
Therefore, the independence of the OPRM process and APRM process is
sufficiently secured. Thus, the power oscillations of the reactor
core can be monitored, and high reliability can be established in
terms of securing the soundness of the core fuel.
[0033] FIG. 3 is a block diagram illustrating the configuration of
a power range monitor according to a third embodiment of the
present invention. The portions that are the same as or similar to
those of FIG. 1 have been denoted by the same reference numerals to
avoid repeating the same description.
[0034] As shown in the diagram, a power range monitor (PRM) 13b
has: LPRM units 1a and 1b, which are the local power range
monitoring devices that obtain the local neutron distribution in a
nuclear reactor core; and an APRM unit 2, which receives the power
output from the LPRM units 1a and 1b, and obtains the average
output power of the entire reactor core.
[0035] The APRM unit 2 includes: an LPRM signal receiving section
6, which receives LPRM signals; an APRM processing section 8, which
orders the APRM to perform a necessary process; and an OPRM
processing section 9, which orders an OPRM process.
[0036] The OPRM processing section 9 and the APRM processing
section 8 have separate reactor-core monitoring functions, and the
function of the OPRM processing section 9 is formed independently
of the function of the APRM processing section 8.
[0037] The APRM unit 2 receives signals from the LPRM unit 1a and
1b.
[0038] The inputting of local power signals to the OPRM processing
section 9 and the inputting of local power signals to the APRM
processing section 8 are performed by the LPRM units 1a and 1b, and
they are shared.
[0039] Once the APRM unit 2 receives the LPRM signals from the LPRM
units 1a and 1b by using the LPRM signal receiving section 6, the
APRM unit 2 separately transmits the received signals to the APRM
processing section 8 and the OPRM processing section 9.
[0040] The PRM 13b has a function to transmit the breakdown or
exclusion signals of any LPRM channels and of the LPRM units 1a and
1b themselves from the LPRM units 1a and 1b to the APRM unit 2.
[0041] When a breakdown or exclusion signal of an LPRM channel of
the LPRM units 1a or 1b is generated, the corresponding LPRM
channel is excluded by an arithmetic operation in the OPRM
processing section 9. Moreover, when a breakdown or exclusion
signal of the LPRM unit 1a or 1b is generated, all the LPRM
channels corresponding to the LPRM units 1a or 1b are excluded by
the OPRM processing section 9.
[0042] According to the present embodiment, the OPRM processing
section 9 is separated from the APRM processing section 8.
Therefore, the independence of the OPRM process and APRM process is
sufficiently secured. Thus, the power oscillations of the reactor
core can be monitored, and high reliability can be established in
terms of securing the soundness of the core fuel.
[0043] The following describes an example of an OPRM unit of a
power range monitor according to a fourth embodiment of the present
invention, with reference to FIG. 1.
[0044] In the OPRM unit 3, for example, the following parameters
and the like are used as initial setting for monitoring
oscillations:
[0045] (1) Primary determination amplitude value (peak); (2)
Secondary determination amplitude value (trough); (3)
Multiplication factor determination value; (4) Trip determination
amplitude value; (5) Oscillation interval minimum determination
value; and (6) Oscillation interval maximum determination
value.
[0046] The above values need to be changed according to type of the
core fuel and the like. Meanwhile, in terms of securing the
soundness of the core fuel, measures to prevent the values from
being easily changed are necessary.
[0047] Accordingly, in the OPRM unit 3, the variables are set by
hardware switches on a board that constitutes part of the OPRM unit
3. That is, in the OPRM unit 3, the variables, which are changed
according to type of the core fuel of the nuclear reactor, are
formed by a combination of electrical contacts that are so
positioned as not to be operated without stopping the oscillation
power range monitoring mechanism.
[0048] According to the present embodiment, the setting values
necessary for the process of monitoring the power oscillations of
the reactor core are set by the hardware switches on the board.
Therefore, it is difficult to change the setting values during
normal operation unless the board is removed, preventing the
variables, which are changed according to type of the fuel of the
reactor core and the like, from being easily changed. Thus, the
power oscillations of the reactor core can be monitored; high
reliability can be established in terms of securing the soundness
of the core fuel.
[0049] The following describes an example of an OPRM unit of a
power range monitor according to a fifth embodiment of the present
invention, with reference to FIG. 1.
[0050] In the OPRM unit 3, parameters, like those described in the
fourth embodiment of the present invention, are used as initial
setting for performing the process of monitoring the power
oscillations of the reactor core. The variables need to be changed
according to type of the core fuel and the like. Meanwhile, in
terms of securing the soundness of the core fuel, measures to
prevent the variables from being easily changed are necessary.
[0051] Therefore, in the OPRM unit 3, the variables are set in
EEP-ROM mounted on the board that constitutes part of the OPRM unit
3. Moreover, the OPRM unit 3 does not include a circuit that
rewrites the EEP-ROM on the board.
[0052] That is, the oscillation power range monitoring mechanism is
so designed that the variables, which are changed according to type
of the core fuel of the nuclear reactor, cannot be changed without
stopping the oscillation power range monitoring mechanism, and are
stored in an element whose internal state cannot be changed by the
operation of the oscillation power range monitoring mechanism.
[0053] The EEP-ROM (Electronically Erasable and Programmable Read
Only Memory) is a kind of nonvolatile memory and is a semiconductor
storage device that can erase or rewrite data by controlling
electricity (voltage). Data can be erased from EEP-ROM by applying
a higher-than-usual level of voltage. Accordingly, the mechanism of
EEP-ROM can be relatively easily realized with no special device.
Therefore, the EEP-ROM is used as a programmable element.
[0054] According to the present embodiment, the setting values
necessary for performing the process of monitoring the power
oscillations of the reactor core are set through the EEP-ROM on the
hoard, and there is no circuit that rewrites the EEP-ROM on the
board. Therefore, it is difficult to change the setting values
during normal operation unless the board is removed, preventing the
variables, which are changed according to type of the core fuel and
the like, from being easily changed. Thus, the power oscillations
of the reactor core can be monitored, and high reliability can be
established in terms of securing the soundness of the core
fuel.
[0055] FIG. 1 is a block diagram illustrating the configuration of
a power range monitor according to a sixth embodiment of the
present invention. The portions that are the same as or similar to
those of FIG. 1 have been denoted by the same reference numerals to
avoid repeating the same description.
[0056] In the OPRM unit 3, the past history needs to be kept for a
predetermined period of time. The history function does not
directly affect the task of securing the soundness of the core
fuel. Therefore, a transmission section 10 is provided in the OPRM
unit 3 of a power range monitor 13c and is connected to a history
recording device 12. The transmission section 10 has a one-way
transmission function to transmit only the output signals not
having input signals.
[0057] Moreover, regarding a display mechanism (not shown) for
monitoring the power oscillations of the reactor core, reliability
is similarly required. Therefore, the one-way transmission of only
the output signals not having input signals is carried out from the
OPRM processing section.
[0058] The output to the history recording device 12 is transmitted
via an optical coupler 11. Therefore, the history recording device
12 is electrically isolated.
[0059] Therefore, even if incompatibility and the like occur in the
history recording device 12 and/or the display mechanism, the
effect is not transmitted to the OPRM unit 3.
[0060] Incidentally, the output signals may be transmitted in a
serial or parallel way in the form of digital data. Alternatively,
the output signals may be transformed into analog data by
converting the signal level into voltage or current values, and
then numerical conversion may be performed by the history recording
device 12.
[0061] In the case of digital transmission, the history recording
device 12 may have not only the function to transmit output signals
in a one-way direction but a function to confirm if data is
normally transmitted by performing parity check to avoid the lack
of data. Moreover, the transmission section 10 may have a function
to retransmit data in accordance with the normal/abnormal
determination result of data transmission from the history
recording device 12 that performs parity check and the like.
[0062] Incidentally, some measures, including the following ones,
need to be taken: checking if the retransmitting function does riot
affect the process of securing the soundness of the core fuel of
the nuclear reactor that the OPRM unit 3 performs; or while data is
buffered in the transmission section 10, a measure, such as one
that directs other processes of the OPRM unit 3 to the transmission
section 10 to one direction, is taken not to affect the previous
processes.
[0063] The parity check is one of the methods to detect errors in
data in data communication. In computers, all data are represented
by sequences of binary numbers, i.e. 0 and 1. The parity check is a
method to detect errors in data using binary numbers.
[0064] Moreover, a determination means (not shown) may be provided
to make a determination as to whether the data is normally
received, and a determination result transmission means (not shown)
may be provided to transmit the determination result of the
determination means to the transmission section 10. Furthermore,
the transmission of data from another oscillation power range
monitoring mechanism (not shown) to the transmission section 10 is
limited to the one-way transmission of output signals.
[0065] According to the present embodiment, while the recording
function of the past history is kept, the OPRM process performed
ensures the necessary reliability for securing the soundness of the
core fuel. Moreover, the transmission of data from the processing
section related to the monitoring of power oscillations of the
reactor core to the display mechanism is limited to the one-way
transmission by which only the output signals not having input
signals are transmitted. Therefore, similar reliability is
maintained for the process of monitoring the power oscillations of
the reactor core.
[0066] The above has described the embodiments of the present
invention. The present invention is, however, not limited to the
above embodiments. Various modifications may occur by combining the
structures of the above embodiments insofar as they are within the
scope of the present invention.
* * * * *