Non-destructive assessment method for radiation damage of nuclear power plant reactor pressure vessel steel

Abstract

The invention discloses a nondestructive evaluation method for irradiation damage of reactor pressure vessel steel of a nuclear power station, and the evaluation method comprises the following steps: (1) monitoring the magnetic remnant MR of the same monitored position of the reactor pressure vessel steel in real time, calculating the initial magnetic remnant rate of change delta MR according to the real-time magnetic remnant MR relative to the magnetic remnant (MR) in a non-irradiated initial state, and calculating the real-time RTNDT, real-time USE, real-time Rm and real-time Rp0.2 in the irradiation damage process of the reactor pressure vessel steel; and (2) analyzing and evaluating the irradiation damage degree of the reactor pressure vessel steel based on the real-time RTNDT, real-time USE, real-time Rm and real-time Rp0.2. Compared with the prior art, the nondestructive evaluation method is economic, environment-friendly, safe and highly efficient, can realize real-time monitoring, has accuracy of data and good safety of testing operation, and can monitor the irradiation damage degrees of a plurality of positions of the reactor pressure vessel.

Description

technical field [0001] The invention belongs to the technical field of nuclear power, and more specifically, the invention relates to a non-destructive evaluation method for radiation damage of nuclear power plant reactor pressure vessel steel. 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 is one of its main failure modes, which is specifically manifested in the increase in strength, decrease in toughness, and material hardening during the irradiation embrittlement of reactor pressure vessel steel. [0003] In order to ensure the safety of reactor pressure vessel operation, th...

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Problems solved by technology

[0008] (1) Due to the limitation of the internal space of the reactor pressure vessel, the number of loaded irradiation supervision tubes is very limited. Since the existing technology cannot realize the installation of radiation supervision tubes after a period of operation, it must be installed once before the first fuel loading operation. This method cannot fully meet the requirements for radiation supervision of reactor pressure vessels during the life extension of nuclear power plants in the future;

[0009] (2) At present, there are only two hot cell institutions in Sichuan and Beijing in China. After the radiation supervision tube is extracted from the reactor pressure vessel, it must be transported from the nuclear power plant to the designated hot cell institution over long distances across provinces. It has very high radioactivity, so the security requirements during transportation are very high, the transportation cost is very high, and the cycle is long;

[0010] (3) Since the mechanical performance test of the irradiation supervision sample is a destructive test, a large amount of radioactive waste will be generated after the test is completed, and the subsequent treatment of the three wastes will be large and costly;

[0011] (4) Since the radiation monitoring samples come from the rest of forgings in the core area, this method can only monitor the damage degree of the reactor pressure vessel core area as a whole, and does not have the ability to monitor other parts of the reactor pressure vessel. , especially the degree of radiation damage at a specific location;

[0012] (5) It does not have the ability to monitor the radiation damage of reactor pressure vessel steel, and can only obtain the radiation damage degree of reactor pressure vessel steel at certain specific time points (depending on the extraction time of the radiation supervision tube)

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