Studying the gaseous fission product release inside the cans of the experimental fuel elements with compacted uranium dioxide

In order to improve the technique for determining the gaseous fission product release in fuel elements under irradiation the kinetics of gas release in the experimental fuel elements with compacted UO2 with density of 10.0 and 10.43 g/cm3 filled with He at the pressure of 0.14-2.49 MPa at fuel burnup upto 4.6% is studied. The fuel element have been irradiated in the SM-2 reactor water cooled low-temperature loop channel cell. The fuel element after-irradiation examination has included measuring the quantity and composition of a gas mixture in fuel cans as well as the analysis of the fuel macro- and microstructure and its composition. Analysis of the data obtained shows that the fuel initial density does not determine the gas release in particular in structures characterized by densification under irradiation. The He initial pressure increase from 0.14 upto 2.49 MPa does not cause the gas release decrease. Relative Xe and Kr ratio in gas mixture inside irradiated fuel elements testifies that Xe release is higher. The conclusion is made that the obtained data give an opportunity to test and correct empirical and analytical models of gas release in fuel elements with UO2