Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
日高 昭秀; 横山 裕也
Proceedings of Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia 2017 (AWC 2017) (USB Flash Drive), p.29 - 42, 2017/09
福島第一原子力発電所事故後期に東海村で測定された空気中のCsの性状が3月30日にガス状から粒子状に変わったことに関し、BC制御材を用いたPhebus FPT3実験やWSPEEDIコードによるソースターム逆算の結果を参照して、CsOHがB
C起源のH
BO
と反応して生成するCsBO
が再蒸発したことが原因であること、また、CsBO
は環境中に放出後、逆反応を起こし、H
BO
が水に溶けたことがBの測定を難しくしているとの仮説を提案した。本仮説に基づく計算は、3月20日以降の炉心冷却注水量の最適化に伴う温度上昇時の環境中への放出量増大と合わせ、放出挙動を的確に再現できたが、推論の実証が重要である。今後は、様々な測定データを詳細に分析し、Bの存在を確認することが重要と考える。
日高 昭秀
no journal, ,
During the Fukushima Daiichi NPP accident, I-131 release could have occurred from a large amount of contaminated water in the basements of Units 2 and 3 reactor buildings because of the gas-liquid partition of I-131 and steam generation from the accumulated water by decay heat. The chemical form of certain fraction of released Cs could have been CsBO, which was formed by reaction of CsOH with the boron originated from the B
C absorbers. The chemical form could affect not only the Cs-137 source term but also the environmental transport behavior. Te-129m release behavior showed that the release from the containment vessel could be affected by the difference in failure location between the top or middle height of drywell without pool and the bottom of suppression pool where the pool scrubbing is expected. These findings have never been considered in most of the existing severe accident codes such as MELCOR that have been developed based on the findings of the TMI-2 accident.