11:30 AM - 11:45 AM
[3G08] Evaluation of Short and Long-Term Behavior of Radioactive Nuclides Distributed in Fukushima Daiichi NPP
8.Evaluation of cesium amounts in the D/W bottom region based on backward evaluation from CAMS data
Keywords:Fukushima Daiichi NPP, severe accident, cesium, CAMS
The measured dose rate for A and B detectors of D/W CAMS for Unit 1 showed the different patterns, which could be clearly explained by applying local wash-out effects. The Cs amounts in the D/W bottom regions for Units 1 – 3 could be evaluated by the BEP. The Cs amounts obtained with the BEP in the D/W bottom region and S/C for Unit 1 were consistent to those with the FEP. The Cs amounts obtained with the BEP in the D/W bottom regions for Units 2 and 3 were more than 10 times as large as those with the FEP. It was concluded that sufficient care should be put on the discrepancy while the FP distribution in the PCV for preparing the safe fuel debris removal was calculated with SA analysis code.