Nuclear reactor control rod bundle assembly in-service inspection device decontamination tool

Abstract

The invention discloses a decontamination tool for an inservice inspection device of a rod cluster control assembly. The decontamination tool comprises a lift ring, a planet carrier, a connection rod and a decontamination rod. The decontamination rod is hollow and divided into a wiping section and a washing section from top to bottom, wherein wiping sponge is arranged on the wiping section in a sleeving mode, and a water outlet is formed in the lateral wall of the washing section. The decontamination tool further comprises a water pump. After once auxiliary centering of a worker, the decontamination tool for the inservice inspection device of the rod cluster control assembly can clean an ultrasonic probe hole, an eddy current probe hole, an encoder roller and a centering device in two modes of wiping and low-pressure water flushing and can decontaminate pollutant like high-dose ash on all radiation hot spot positions in distance. Compared with manual decontamination, the decontamination methods of wiping decontamination and water flushing decontamination can greatly reduce near operation time of workers, are higher in decontamination level and greatly reduces collective dose bored by worker during following-up assembling and disassembling, transportation, maintenance and another inspection of equipment.

Description

technical field [0001] The invention relates to the field of nuclear power detection, in particular to a decontamination tool for an in-service inspection device of a nuclear reactor control rod bundle assembly. Background technique [0002] Nuclear reactor control rod cluster assembly (Rod Cluster Control Assembly, hereinafter referred to as RCCA) is a tool for rapid control of reactivity. Heap to ensure nuclear safety. RCCA has been in the special working conditions of high temperature, high radioactivity, and reciprocating mechanical movement for a long time. Thermal aging of metal materials and contact wear between RCCA and guide plate will lead to swelling, wear, cracks and other defects in service for a certain period of time. Therefore, it is necessary to conduct regular in-service inspections, conduct qualitative and quantitative assessments of existing defects, and compare with historical inspection data to evaluate the speed and trend of swelling, wear and cracks ...

AI Technical Summary

Problems solved by technology

[0004] At present, the decontamination of radioactive equipment at home and abroad mainly adopts wiping, washing, ultrasonic decontamination and other methods. In practice, the exposure dose rate of RCCA equipment is as high as 10-250mSv, mainly offshore washing and manual wiping decontamination. The operation is labor-intensive, takes a long time, and the exposure dose is high

In terms of decontamination equipment, there is also a set of bubbling decontamination tools aimed at developing in China, such as the decontamination tool disclosed by the patent of CN 103157627 B. The escaping gas forms air bubbles, and the air bubbles impact the inspection device to form vibrations to clean the pollutants. However, due to the small vibrations, only loose pollutants on the surface of the centering device can be removed, and it is impossible to completely remove the pollutants with strong adhesion. Strong dust dust, resulting in high radiation dose of the inspection device

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