Probe assembly of control rod guiding cylinder cotter pin of nuclear power station

Abstract

The invention discloses a probe assembly of a control rod guiding cylinder cotter pin of a nuclear power station. The probe assembly comprises a probe wafer, a wafer fixing frame for fixing the probewafer, a bottom plate and a first buffering assembly connected between the bottom plate and the wafer fixing frame; a second buffering assembly is further arranged between the first buffering assemblyand the wafer fixing frame; the second buffering assembly comprises a middle plate connected with the first buffering assembly, a cylinder body which sleeves the middle plate and an elastic rubber ring fixed in the cylinder body; the wafer fixing frame is fixedly inserted into the elastic rubber ring and a gap is formed between the elastic rubber ring and the middle plate; the height, which is higher than the second buffering assembly part, of the probe wafer and the wafer fixing frame is greater than the distance between the deepest part of a cotter pin groove and the lower end face of an upper grid plate and the distance is a compression distance. The probe assembly disclosed by the invention can be self-adaptive to positioning errors and mounting errors; the contact pressure between anultrasonic probe and the cotter pin is constant and the repeatability of ultrasonic examination is easy to realize.

Description

technical field [0001] The invention relates to the field of nuclear power detection, in particular to a cotter pin probe assembly of a control rod guide cylinder of a nuclear power plant. Background technique [0002] The cotter pin of the control rod guide cylinder is located in the upper reactor internals of the nuclear power plant reactor, and its function is to provide positioning and lateral support for the control rod guide cylinder, and is an important factor affecting whether the control rod can fall as required during power adjustment and emergency shutdown of the nuclear power unit . Cotter pin failures have occurred many times in foreign nuclear power plants. The consequences are reflected in two aspects. One is the dislocation of the control rod guide tube, which affects the falling time of the control rods. The other is that the broken cotter pin parts enter the primary circuit of the nuclear power plant as foreign objects and circulate , will damage other imp...

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Problems solved by technology

Moreover, the end of the cotter pin is recessed into the bottom surface of the upper grid plate by 37.75mm, which brings great difficulty to the observation and positioning of the end surface of the cotter pin.

In addition, after the nuclear power unit has been in operation for more than 20 years, factors such as deformation of parts and assembly tolerances may cause the cotter pin to be deflected to a certain extent, so the probe assembly must be flexible to adapt to this situation; in addition, due to the ultrasonic probe and the cotter pin Constant contact pressure is conducive to the repeatability of ultrasonic inspection, and in order to provide this constant pressure, it is often necessary to set up a pressure detection and adjustment mechanism, which is extremely difficult to set up on a small probe assembly

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