Radiation damage monitoring method for nuclear power plant reactor pressure vessel

Abstract

The invention discloses a nuclear power plant reactor pressure vessel irradiation damage monitoring method which comprises the following steps: measuring the initial nano-indentation hardness h0 of a reactor pressure vessel steel monitoring part before the first charging operation of a nuclear power plant; measuring the nano-indentation hardness h of the same monitoring part of the reactor pressure vessel steel at any time point after irradiation damage during normal operation of the nuclear power plant; calculating a nano-indentation hardness change rate delta (h) of the reactor pressure vessel steel in the irradiation damage process based on the initial nano-indentation hardness h0 and the nano-indentation hardness h measured at any time point, and calculating strength parameters of the reactor pressure vessel steel in the irradiation damage process according to the nano-indentation hardness change rate delta (h); and analyzing and evaluating the irradiation damage degree of the reactor pressure vessel steel based on the strength parameters. The monitoring method disclosed by the invention is economic, environment-friendly, safe and efficient, repeated measurement can be realized, and the irradiation damage degrees of multiple positions of the reactor pressure vessel can be simultaneously monitored.

Description

technical field [0001] The invention belongs to the technical field of nuclear power, and more specifically, the invention relates to a method for monitoring radiation damage 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 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, the traditional r...

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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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