FP Release behavior form irradiated MOX fuel

Hirosawa, Takashi  ; Sato, Isamu; Morozumi, Katsufumi; Namekawa, Takashi; Takai, Toshihide  ; Nakagiri, Toshio  ; not registered  

Fission products (FPs) release tests from irradiated MOX fuel were performed in Alpha Gamma Facility (AGF) from viewpoint of "source term" evaluation. "Source term"means the species and the quantity of FPs and so on discharged to environment during nuclear reactor accidents. The tests are carried out two times, which names are "FP-1" and "FP-2", respectively. ln "FP-1" test, a fuel sample was heated for 30 minutes at 2000C, and then for 30 minutes at 3000C. In "FP-2", it did for 30 minutes at 1500C, and then for 30 minutes at 2500C. The heating rate is 15 K/sec for any heating processes. The samples (about 10g of weight) for the tests were irradiated to approximately 65 GWd/t in the experimental fast reactor, "Joyo", which cladding materials were removed. The Pu content and initial O/M ratio for each sample is 29wt% and 1.99, respectively. During and after the test, FP release behavior was observed with -ray spectrometry, gas mass analysis and gas chromatograph. (1)The -ray spectrometry mainly revealed the release and adhesion on sampling parts of Cs. The results of these experiments are as follows; (a)Cs suddenly was released from the sample as soon as the temperature was elevated. The peaks of Cs-134 and Cs-137 release rate are not identical. This probably results from difference of distribution between Cs-134 and Cs-137. (b)The adhesion profile of Cs on the sampling tubes is a function of the sampling tube temperature, and the adhesion quantity is large at regions less than 600C. (c)About 70% of Cs releasing from the sample stuck on sintered metal filters for both FP-1 and FP-2 test. Cs quantities sticking on all of the sampling parts are identical for FP-1 and FP-2. (d)Rh(Ru)-106 and Eu-154 were scarcely released from the samples. (2)The gas analyses mainly revealed the release behavior of Kr and Xe. The results are summarized as follows; (a)Kr suddenly was released from the sample as ...