CN-120432207-B - Nuclear power plant reactor core fuel assembly fission product nuclide on-line monitoring method and system

CN120432207BCN 120432207 BCN120432207 BCN 120432207BCN-120432207-B

Abstract

The invention discloses a nuclear power plant reactor core fuel assembly fission product nuclide online monitoring method and system, wherein the method comprises the following steps of obtaining each theoretical deposition monograph based on the energy scale of an actual measurement monograph of the nuclear power plant reactor core fuel assembly fission product nuclide; and calculating the theoretical deposition spectrum by a preset algorithm to obtain the activity value of nuclide, thereby realizing the on-line monitoring of the nuclide of the fission product of the fuel assembly of the reactor core of the nuclear power plant. The invention corrects the spectrum drift in the actually measured single spectrum in real time and realizes the detection of the nuclear activity of fission product nuclides, particularly low-energy-section nuclides of the nuclear power plant reactor core fuel assembly.

Inventors

LI JIAGEN
XIE WEIRONG
ZENG YUAN
CHU JIANWEI
LI PENG
HE WEIHUA
GE CHUANNING
WANG SONG
GUO JUAN
CAO XIN
LIU DAN
LIN JIEDONG
XIANG WENXIN
WANG YONGGANG
YANG ZI
PAN HONGLIANG
NING FANGMAO

Assignees

台山核电合营有限公司
北京智崴科技发展有限公司

Dates

Publication Date: 20260508
Application Date: 20250402

Claims (8)

1. An on-line monitoring method for nuclear power plant reactor core fuel assembly fission product nuclides is characterized by comprising the following steps: The method comprises the steps of converting the channel address of each measured spectrum into an energy scale parameter based on the measured spectrum of the nuclear power plant reactor core fuel assembly fission product nuclide to obtain each theoretical deposition spectrum, wherein the formula for converting the channel address of each measured spectrum into the energy scale parameter is as follows: , wherein, Energy scale parameters of the single spectrum are deposited for the ith theory, The channel address of the ith measured single spectrum, i is the ith theoretical deposition single spectrum, and a, b and c are conversion factors; Correcting and superposing all theoretical deposition energy spectrums to obtain theoretical deposition combined spectrums, wherein each theoretical deposition spectrum corresponding to each actual measurement spectrum is corrected according to a count compensation factor corresponding to each actual measurement spectrum to obtain corrected theoretical deposition spectrums; And calculating a theoretical deposition spectrum through a preset algorithm to obtain the activity value of the nuclide, so as to realize the on-line monitoring of the nuclide of the fission product of the reactor core fuel assembly of the nuclear power plant.
2. The nuclear power plant reactor core fuel assembly fission product nuclide online monitoring method of claim 1, wherein the count compensation factor corresponding to each measured spectrum is obtained by dead time correction of dead time corresponding to each measured spectrum; The formula for calculating the counting compensation factor corresponding to each measured single spectrum is as follows: , wherein, A count compensation factor corresponding to the ith theoretical deposition profile, i being the ith theoretical deposition profile, Is the total count value of the full spectrum, t is the total measurement time, To measure dead time.
3. The method of claim 2, wherein the measured dead time corresponding to each measured spectrum is obtained by subtracting the measured active time corresponding to each measured spectrum from the total measured time corresponding to each measured spectrum, and/or The measured total time corresponding to each measured single spectrum is calculated by each background counting rate and each nuclide counting rate.
4. The nuclear power plant core fuel assembly fission product nuclide online monitoring method of claim 1, wherein the number of all corrected theoretical deposition profiles is the number of all theoretical deposition profiles, and the number of all theoretical deposition profiles is calculated by measuring total time of the measured profiles.
5. The method of on-line monitoring nuclear power plant core fuel assembly fission product nuclides of claim 1, wherein linearly superimposing all corrected theoretical deposition mono-spectra to obtain a theoretical deposition composite spectrum comprises: and linearly superposing the count values of all energy points of all the corrected theoretical deposition single spectrums to obtain a theoretical deposition combined spectrum.
6. The method for on-line monitoring of nuclear power plant core fuel assembly fission product nuclides as set forth in claim 5, wherein linearly superimposing the count values of each energy point of all corrected theoretical deposition mono-spectrums to obtain a theoretical deposition combined spectrum comprises: Linearly superposing count values of the same energy points in all the corrected theoretical deposition single spectrums; and obtaining count values corresponding to different energy points through a preset algorithm for different energy points in all the corrected theoretical deposition single spectrums, and performing linear superposition to obtain theoretical deposition combined spectrums.
7. The nuclear power plant core fuel assembly fission product nuclide on-line monitoring method of claim 1, wherein the nuclear power plant core fuel assembly fission product nuclide on-line monitoring is realized by calculating an activity value of nuclides through a preset algorithm on a theoretical deposition spectrum, and the method comprises the following steps: And selecting a standard peak shape closest to the peak shape of the theoretical deposition spectrum, performing peak shape fitting on the theoretical deposition spectrum, and calculating the fitted theoretical deposition spectrum peak shape to obtain the activity value of the nuclide, thereby realizing the on-line monitoring of the nuclide of the fission product of the nuclear power plant reactor core fuel assembly.
8. A nuclear power plant core fuel assembly fission product nuclide on-line monitoring system, comprising: The energy scale module is used for performing energy scale on the basis of the actually measured single spectrum of each nuclide of the nuclear reactor to obtain each theoretical deposition single spectrum, and comprises the following steps of converting the channel address of each actually measured single spectrum into energy scale parameters to obtain each theoretical deposition single spectrum based on the actually measured single spectrum of the nuclide of the fission product of the nuclear power plant reactor core fuel assembly, wherein the formula for converting the channel address of each actually measured single spectrum into the energy scale parameters is as follows: , wherein, Energy scale parameters of the single spectrum are deposited for the ith theory, The channel address of the ith measured single spectrum, i is the ith theoretical deposition single spectrum, and a, b and c are conversion factors; The correction superposition module is used for correcting and superposing all theoretical deposition energy spectrums to obtain theoretical deposition combined spectrums, and comprises the steps of correcting all theoretical deposition single spectrums corresponding to the actual measurement single spectrums according to counting compensation factors corresponding to the actual measurement single spectrums to obtain corrected theoretical deposition single spectrums, linearly superposing all corrected theoretical deposition single spectrums to obtain theoretical deposition combined spectrums, and And the activity value calculation module is used for calculating the theoretical deposition spectrum through a preset algorithm to obtain the activity value of the nuclide so as to realize the on-line monitoring of the nuclide of the fission product of the reactor core fuel assembly of the nuclear power plant.

Description

Nuclear power plant reactor core fuel assembly fission product nuclide on-line monitoring method and system Technical Field The invention relates to the technical field of nuclear power, in particular to a nuclear power plant reactor core fuel assembly fission product nuclide on-line monitoring method and system. Background When the fuel assembly cladding runs for a long time in the stack, tiny cracks can be formed in the fuel assembly cladding early due to hydrogenation or abrasion, fission product nuclides in the fuel assembly cladding can be released into a loop coolant from the cracks, so that the radioactivity level in the coolant is increased, and if small cracks in the early stage of the fuel assembly cladding can not be found in time, the fuel assembly cladding can be deteriorated to be large cracks or a plurality of cracks under the secondary hydrogenation, and the running safety of the reactor and the personnel radiation safety are affected. After the long-term operation of the reactor, when the fuel assembly cladding is damaged, the early tiny size occurs, a small amount of fission product nuclides (such as Xe-133, xe-135, I-131, kr-85m and the like) released by the fuel assembly cladding can be seriously influenced by a large amount of activated products existing in the inner wall of a pipeline or cooling water of a loop and Compton scattering of the activated products, a characteristic peak of the low-energy nuclide is superimposed on the background, and if the background of the low-energy nuclide of a gamma energy spectrum is incompletely subtracted, the characteristic peak parameter extraction superimposed on the characteristic peak is influenced, and especially when the content of the low-energy nuclide in a measured object is low, the activity analysis of the low-energy nuclide is influenced. In order to increase the energy spectrum analysis efficiency of the target nuclide with low concentration and low energy section released in early stage of fuel breakage, generally, when gamma spectrum data of the nuclide with low concentration is acquired, the statistics is better as the measurement count value is accumulated more, then under a certain counting rate, the statistics is better as the measurement time is longer, but due to the influence of factors such as environmental temperature, power supply, electronic system, aging, radiation, vibration, humidity, power supply noise and the like, the parameters of a spectrometer system are always changed, so that the characteristic peak position or the whole spectral line of the target nuclide continuously drifts in the measurement process, finally, the long-time measurement spectrum is widened, the energy resolution of gamma energy spectrum is reduced, the characteristic peak of the target nuclide with low energy section in the superposition spectrum is still weaker, the energy spectrum analysis is inaccurate, and the on-line monitoring of the fission product nuclide of the fuel assembly of a nuclear power plant is inaccurate. Disclosure of Invention Aiming at least one defect of the related technology in the background technology, the invention provides a nuclear power plant reactor core fuel assembly fission product nuclide online monitoring method and a system, aiming at the defects that the energy resolution of a gamma energy spectrum is reduced due to drift of a nuclear power plant reactor core fuel assembly fission product nuclide characteristic peak shape in a measurement process and energy spectrum analysis is inaccurate due to weak characteristic peaks of low-energy-section nuclides in a superimposed spectrum. The technical scheme adopted for solving the technical problems is that an on-line monitoring method for nuclear power plant reactor core fuel assembly fission product nuclide is constructed, and the method comprises the following steps: Based on the measured single spectrum of the fission product nuclide of the nuclear power plant reactor core fuel assembly, performing energy scale to obtain each theoretical deposition single spectrum; correcting and superposing all theoretical deposition energy single spectrums to obtain a theoretical deposition combined spectrum; And calculating a theoretical deposition spectrum through a preset algorithm to obtain the activity value of the nuclide, so as to realize the on-line monitoring of the nuclide of the fission product of the reactor core fuel assembly of the nuclear power plant. In some embodiments, deriving the theoretical deposition profile based on the measured profile of nuclear power plant core fuel assembly fission product nuclides includes: Converting the channel address of each measured spectrum into an energy scale parameter based on the measured spectrum of the fission product nuclide of the nuclear power plant reactor core fuel assembly to obtain each theoretical deposition spectrum; the formula for converting the channel address of each actually measured single spectrum into th