Evaluation method for maintenance opportunity of nuclear reactor containment internal coating layer

Abstract

The invention relates to an evaluation method for a maintenance opportunity of a nuclear reactor containment internal coating layer. The evaluation method successively comprises the following steps: (a) determining the area S of a nuclear reactor containment break affected zone, and calculating the mass M[1] of latent coating layer fragments; (b) carrying out visual inspection on four coating layer systems of a nuclear reactor containment outside the break affected zone; (c) followed by testing tested points, and recording test results; (d) determining LOCA simulation test unqualified ratios of the four coating layer systems; (e) combining with a formula 2, respectively calculating the total mass M[2] of the latent fragments outside the break affected zone; (f) determining the mass M[3] of a qualified coating layer falling off during a reactor machine set normal operation; (g) determining X[CCD] and the maximum value M[max] of all the coating layer fragments produced from loss of coolant accidents; and (h) according to a formula (3), calculating the approximation rate gamma. The evaluated total amount of the coating layer fragments is quantized and is compared with the amount of critical coating layer fragments, so as to confirm whether a nuclear reaction is required to be stopped for maintenance of the coating layer in the containment.

Description

technical field [0001] The invention relates to a method for evaluating the maintenance timing of a nuclear reactor, in particular to a method for evaluating the maintenance timing of the inner coating of the nuclear reactor containment vessel. Background technique [0002] A nuclear reactor, also known as an atomic reactor or a reactor, is a device that can maintain a controllable self-sustaining chain nuclear fission reaction and is equipped with nuclear fuel to achieve a large-scale controllable fission chain reaction. Reactor containment (also known as reactor protective shell) is a closed container that prevents radioactive materials from escaping when the nuclear reactor is in operation or in an accident. When an accident occurs in a nuclear power plant reactor, a large amount of radioactive substances will be released. As the last nuclear safety barrier, the containment can prevent the spread of radioactive substances and pollute the surrounding environment; at the s...

AI Technical Summary

Problems solved by technology

Due to the large coating area, complex irradiation environment, and few movable windows, the inner coating of the reactor containment basically does not meet the conditions for large-scale maintenance. The continuous increase of coating fragments increases the risk of recirculation pit blockage failure, which brings risks to the safe operation of the reactor; however, it is impossible to easily stop the nuclear reaction during the operation of the reactor and carry out the maintenance of the coating inside the containment vessel. Otherwise, a lot of material and financial resources will be wasted, so a scientific method is needed to determine the timing of the coating repair in the containment