Nuclear fuel rod active detection system and method

Abstract

The invention relates to an active detection system for a nuclear fuel rod. The system comprises a neutron source, a moderation shielding body, a scintillator detector array, a multichannel nuclear electronics and data acquisition system, a computer software system, a feeding and discharging frame and an automatic control system; the neutron source is arranged in the moderation shielding body, andthe detector array is arranged at the front end of the scintillator detector array; the scintillator detector array is located on a fuel rod detection channel activated by a fuel rod and is used fordetecting gamma rays emitted by the fuel rod activated by a neutron source, wherein the number of detectors in each channel detector array is greater than 6, and a hole channel for the fuel rod to pass through is formed in a detector crystal. According to the invention, a neutron source with a long half-life period can be used, so the active detection system does not need to replace the radioactive source in the whole life period; or the service time of the 252Cf neutron source arranged in the original active equipment can be prolonged, the frequency of changing the source is reduced, and theequipment operation cost is saved.

Description

technical field [0001] The invention belongs to the nuclear fuel rod non-destructive detection technology, in particular to a nuclear fuel rod active detection system and method. Background technique [0002] The nuclear fuel rod is the unit body of the reactor that releases heat, and is the core component of the reactor. Nuclear fuel rods are in a strong neutron field when the reactor is running, and they have to withstand high temperature, high pressure, and high flow rate coolant, and at the same time bear the chemical action of fissile substances and complex mechanical loads, steam corrosion, and the working conditions are very harsh. Inconsistencies between manufacturing characteristics such as the abundance of pellets in nuclear fuel rods, surface boron coating thickness, or gadolinium content and design values ​​will cause the core reactivity to deviate from expectations, increase the difficulty of reactor control, and affect reactor operation. Therefore, 100% inspec...

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Problems solved by technology

[0004] because 252 Cf has a half-life of 2.7 years, loaded with 1.2mg 252 After less than two half-lives (less than 5 years) of the equipment of the Cf neutron source, due to the decrease of the neutron output, the detection ability of the equipment on the fuel rods is reduced, and it is difficult to meet the detection requirements. At this time, it is necessary to purchase new ones. 252 Cf neutron source to improve the detection capability of the equipment, while 252 The Cf neutron source cannot be produced domestically, and needs to be imported from Russia and the United States, which is expensive, resulting in a high cost of fuel rod production

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