System and process for releasing and measuring fission gas of heavy-water reactor fuel elements

Abstract

The invention discloses a system for releasing and measuring fission gas of heavy-water reactor fuel elements. The system comprises a drilling device (1), a calibrating mechanism (2), a collecting device (3) and a vacuum unit (4). The drilling device (1) is used for drilling the heavy-water reactor fuel elements (7) and completely releasing the fission gas, the calibrating mechanism (2) is used for measuring the volumes of cavities inside the heavy-water reactor fuel elements (7), the collecting device (3) is used for pressurizing and collecting the fission gas released by the drilling device (1), and the vacuum unit (4) is used for vacuumizing the drilling device (1), the calibrating mechanism (2) or the collecting device (3). The invention further discloses a process for releasing and measuring the fission gas. The system and the process have the advantages that technologies for releasing and collecting the fission gas of the heavy-water reactor fuel elements are established, and accordingly the fission gas of the heavy-water reactor fuel elements can be released, collected and measured.

Description

technical field [0001] The invention relates to the technical field of nuclear fuel cycle, in particular to a heavy water reactor fuel element fission gas release and measurement system and process. Background technique [0002] In order to alleviate the pressure on uranium resources brought about by the rapid development of my country's nuclear power plants, the pressure on the disposal of spent fuel components in PWRs, and solve the future development direction of heavy water reactors, my country has carried out the test and verification of the application of uranium recovered from PWRs to fuel components in heavy water reactors to evaluate The irradiation performance of fuel elements, among which the fission gas release rate is a key technical index to evaluate the irradiation performance of fuel elements. This is because the fission products Kr and Xe are released from the fuel pellets into the cavity between the cladding and the fuel pellets, on the one hand, it will cau...

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Problems solved by technology

This is because the fission products Kr and Xe are released from the fuel pellets into the cavity between the cladding and the fuel pellets, on the one hand, it will cause the radiation swelling of the fuel pellets, resulting in the intensification of the interaction between the fuel pellets and the cladding; On the other hand, the internal pressure of the fuel element is increased, resulting in an increase in the internal pressure of the fuel element and a decrease in thermal conductivity. The decrease in thermal conductivity will cause an increase in the temperature of the pellet, which will promote the release of fission gas from the fuel pellet, resulting in an increase in the internal pressure of the element. Further increase, forming a vicious circle, leading to failure of fuel elements in severe cases, and even affecting the safe operation of the reactor

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