Post-irradiation fuel rod underwater diameter measuring system and measuring method thereof

Abstract

The invention discloses a post-irradiation fuel rod underwater diameter measuring system, which comprises a spent fuel pool. A diameter measuring unit, which faces a fuel component, is arranged in the spent fuel pool. The diameter measuring unit is connected to a signal collecting and processing system. The operation is convenient. Through the micro displacement change between contact sheets, the displacement change is converted into the coil mutual inductance coefficient change, finally the displacement change is converted into voltage, the conversion between non electrical quantity and electrical quantity is realized, the diameter of a peripheral fuel rod of a fuel assembly can be rapidly and instantly measured underwater on site; a contact type electric signal transmission and conversion mode is adopted, and the measurement precision and detection efficiency are largely improved.

Description

technical field [0001] The invention belongs to the field of poolside inspection of irradiated fuel assemblies in the nuclear fuel cycle, and in particular relates to an underwater diameter measurement system and method for irradiated fuel rods. Background technique [0002] Fuel assemblies in nuclear power plants are subject to increasingly harsh operating conditions such as high fuel consumption, chemical changes in long-term circulating water, and high power peak factors when low leakage occurs. Fuel assemblies are easily deformed and cannot be returned to the stack for reuse. Fuel rods swell after irradiation. Even broken. As an effective means of evaluating the radiation stability and integrity of fuel assemblies, poolside inspection technology undertakes an important task to ensure the safe operation of nuclear power plants. [0003] Traditional fuel rod diameter measurement methods generally use vernier calipers, laser micrometers, laser profilers and other means, an...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is that there are problems of low measurement accuracy and low work efficiency in the existing fuel rod underwater diameter measurement, and a fuel rod underwater diameter measurement system and its measurement method after irradiation are provided. The change of the small displacement between them is converted into the change of the mutual inductance coefficient of the coil, and then converted into a voltage, and finally realizes the conversion of non-electricity and electric quantity, and realizes the precise measurement of the diameter of the fuel rod around the fuel assembly after irradiation.

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