Method for monitoring neutron irradiation damage fluence of reactor pressure vessel in nuclear power plant

Abstract

The invention discloses a method for monitoring neutron irradiation damage fluence of a reactor pressure vessel in a nuclear power plant. The method comprises the following steps of 1, monitoring a magnetic performance parameter of a certain monitored part of steel of the reactor pressure vessel during normal running of the nuclear power plant in real time, wherein the magnetic performance parameter is any one of magnetic susceptibility x, remanent magnetization MR and coercive force HC; calculating the neutron irradiation damage fluence phi of the reactor pressure vessel on the basis of the magnetic performance parameter obtained in real time. Compared with the prior art, through the adoption of the method for monitoring the neutron irradiation damage fluence of the reactor pressure vessel in the nuclear power plant, magnetic performance parameters of the steel of the reactor pressure vessel during normal running of the nuclear power plant can be tested in real time and continuously, neutron irradiation damage fluence data of the steel of the reactor pressure vessel is calculated and obtained in real time, and the neutron irradiation damage fluence of multiple positions of the reactor pressure vessel can be monitored simultaneously.

Description

technical field [0001] The invention belongs to the field of nuclear power, and more specifically, the invention relates to a method for monitoring neutron irradiation damage fluence of a reactor pressure vessel of a nuclear power plant. Background technique [0002] The reactor pressure vessel is one of the most critical large-scale equipment in the nuclear island of a nuclear power plant. Its main function is to contain and support the steel pressure vessel of the core nuclear fuel assembly, control assembly, reactor internals and reactor coolant. It has served in strong irradiation, high temperature, and high pressure environments for a long time, and neutron irradiation damage (specifically manifested as increased strength and decreased toughness during the irradiation embrittlement of reactor pressure vessel steel) is one of its main failure modes. [0003] In order to ensure the safety of reactor pressure vessel operation, monitoring and evaluating its radiation damage...

AI Technical Summary

Problems solved by technology

[0005] 1) Fission dose detector (U 238 and Np 237 ) is a radioactive source, and its production, transportation, and sales all require professional qualifications, the procurement cost is very high, and subsequent transportation and compliance are extremely troublesome;

[0006] 2) The radiation damage fluence of the reactor pressure vessel body cannot be directly obtained, and it needs to be converted by the lead factor, and there is a certain error. When the lead factor is large, the error becomes more obvious, and the neutron radiation damage fluence obtained at that time is poor representation;

[0007] 3) Since the number of radiation supervision tubes is very limited (usually only 4 to 6, and must be loaded once before the first loading operation, the existing technology cannot realize the installation of radiation supervision tubes after a period of operation, This problem will become more prominent when the life of nuclear power plants is extended in the future), and the number of corresponding fission dose detectors is only 4 to 6. Therefore, the neutron radiation damage fluence of reactor pressure vessel steel cannot be continuously obtained by this method; It will take at least one year to supervise the extraction, transportation, cutting and dissection of the tube, and the test and analysis of the fission dose detector. There is also an obvious time lag in obtaining the neutron radiation damage fluence of reactor pressure vessel steel by this method;

[0008] 4) The fission dose detector is a one-time product, and has strong radioactivity after use. At the same time, a large amount of radioactive waste is also generated in the analysis and testing process. The subsequent treatment of three wastes is relatively large and the cost is high;

[0009] 5) The above method can only monitor the neutron radiation damage fluence in the core area of ​​the reactor pressure vessel as a whole, and does not have the ability to monitor the radiation damage fluence of other parts of the reactor pressure vessel, especially the radiation damage in a specific position

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