Fission Gas Release Measurement for Re-irradiated Fuel Rods

Fission gas release measurement of reactor fuel rods is one of the main issues of post-irradiation examination, which plays a key role to the evaluation of fuel performance. The re-irradiated fuel assembly consisits of 3 spent fuel rods, 4 as-fabricated fuel rods and 2 control rod guide tubes, and is re-fabricated in the hot cell. It was found to be failure when burnt to burnup of 30. 9 GW · d/t and therefore sent to the hot laboratory for examination. With conventional non-destructive examination methods, no fuel rod was found to be cracked. Eventually laser puncture was used to decide if the fuel rods were failed or not depended on the measurement of internal pressure of the fuel rods. After that, fission gas release rate was measured by means of gas chromatograph. Results show that all fuel rods are not cracked, and fission gas release rate is not too much more compared with the first term irradiated fuel assembly.