Neutron flux measuring thimble tube replacing process of nuclear reactor core measuring system and specific device thereof

Abstract

The invention relates to a nuclear reactor core measuring system of a reactor of a pressurized water reactor nuclear power plant, specifically relates to a neutron flux measuring thimble tube replacing process of a nuclear reactor core measuring system and a specific device thereof. The method comprises the following steps of: firstly confirming the requirements of replacing irradiated thimble tube and the position of reactor core of the irradiated thimble tube and the accurate length, and then confirming whether the irradiated thimble tube to be replaced is broken; for the thimble tube prevented from braking, the process for taking out the reactor core of the thimble tube is carried out in one time; for the thimble tube broken, the process for taking out the reactor core of the thimble tube is carried out by sectioning; and the method further comprises a step of inserting a new thimble tube of which the size is in line with that of the irradiated thimble tube to be replaced after confirming the thimble tube is normal. The neutron flux measuring thimble tube replacing process of a nuclear reactor core measuring system and the specific device thereof provided by the invention have the advantages that the security of replacement of the thimble tube is ensured, the operation of the tool is reliable, the application is convenient, and the cost is low.

Description

technical field [0001] The invention relates to a reactor core inspection system of a pressurized water reactor nuclear power plant, in particular to a neutron flux measurement finger bushing replacement process and special equipment for the reactor core inspection system. Background technique [0002] The finger sleeve, made of austenitic stainless steel, has a warhead-shaped head welded at one end extending into the fuel assembly, and a flange-shaped limiter welded at one end of the instrument chamber, which is a neutron flux measuring instrument components of the system. It is mainly used to measure the flux distribution of thermal neutrons in the core, so as to obtain a very accurate flux distribution map over the entire height of the fuel assembly. [0003] The finger sleeve is inserted into the neutron flux measurement guide sleeve of the fuel assembly under normal operating conditions; before the core refueling of the nuclear power plant, the finger sleeve is pulled ...

AI Technical Summary

Problems solved by technology

And this extraction device has only one lead can, which means that only one finger cannula can be replaced at a time

In addition, this extraction device cannot be used for broken finger sleeves

[0006] If the irradiated finger sleeve is broken and severely worn, if it is not replaced and treated, it will seriously affect the safety of the reactor operation, and even lead to the occurrence of nuclear safety accidents

[0007] The replacement process does not consider the replacement of irradiated finger sleeve fractures, and there are imperfections in the replacement process, such as: radioactive irradiation of waste finger sleeves; leakage of radioactive sewage after the finger sleeves are pulled out; finger sleeves The fracture during tube extraction cannot be handled; the foreign matter in the guide sleeve is checked and confirmed; especially when it is broken into multiple segments, etc.

[0008] In addition, the replacement process operation monitoring and confirmation methods are insufficient; one-way extraction, the jamming process is helpless, and the remote extraction of the finger sleeve is likely to cause damage and fracture, which is very risky

Images