Toward evaluation of cesium chemistry during transportation in a boiling water reactor; Effects of boron on cesium chemistry

Miwa, Shuhei; Miyahara, Naoya*; Nakajima, Kunihisa; Imoto, Jumpei; Suzuki, Eriko

Nihon Genshiryoku Gakkai-Shi ATOMO, 63(12), p.825 - 829, 2021/12

https://doi.org/10.3327/jaesjb.63.12_825

In the BWR severe accident, it was indicated that the control material boron significantly influences chemical behavior and transition behavior of cesium, which is important from the viewpoint of exposure, and it causes great uncertainty in the prediction of environmental release and distribution in the reactor. Therefore, in order to elucidate the important chemistry to be considered in severe accident analysis, we have developed the experimental setup that enables the evaluation of chemistry during transportation in the reactor, and evaluated cesium chemistry. Based on the results, we developed the chemistry database named ECUME composed of datasets and models that are the basis of chemical reaction analysis so that chemical behavior could be evaluated by severe accident analysis code.

Experimental determination of the photooxidation of aqueous I as a source of atmospheric I

Watanabe, Kosuke*; Matsuda, Shohei; Cuevas, C. A.*; Saiz-Lopez, A.*; Yabushita, Akihiro*; Nakano, Yukio*

ACS Earth and Space Chemistry (Internet), 3(4), p.669 - 679, 2019/04

https://doi.org/10.1021/acsearthspacechem.9b00007

The photooxidation of aqueous iodide ions (I) at sea surface results in the emission of gaseous iodine molecules (I) into the atmosphere. It plays a certain role in the transport of iodine from ocean to the atmosphere in the natural cycle of iodine. In this study, we determined the photooxidation parameters, the molar absorption coefficient (()) and the photooxidative quantum yields (()) of I, in the range of 290-500 nm. Through the investigation of the influence of pH and dissolved oxygen (DO) on (), the subsequent emission rates of I following the photooxidation of I in deionized water solution (pH 5.6, DO 7.8 mg L) and artificial seawater solution (pH 8.0, DO 7.0 mg L) were estimated. A global chemistry-climate model employed herein to assess the I ocean emission on a global scale indicated that the photooxidation of I by solar light can enhance the atmospheric iodine budget by up to 8% over some oceanic regions.

JAERI's hot stuff

Sakaba, Nariaki; Tachibana, Yukio; Onuki, Kaoru; Komori, Yoshihiro; Ogawa, Masuro

Nuclear Engineering International, 50(612), p.20 - 22, 2005/07

The HTTR (High Temperature Engineering Test Reactor) at Japan Atomic Energy Research Institute's Oarai Research Establishment attained its maximum reactor-outlet coolant temperature of 950C in April 2004 and ready to connect nuclear heat for industrial applications. The hydrogen production system by thermochemical water-splitting Iodine Sulphur cycle is also developing and succeeded to produce 30 normal L/h hydrogen in a closed cycle in June 2004.

International Standard Problem (ISP) No.41; Computer code comparison exercise based on a Radioiodine Test Facility (RTF) experiment on iodine behaviour in containment under severe accident conditions

Ball, J.*; Glowa, G.*; Wren, J.*; Rydl, A.*; Poletiko, C.*; Billarand, Y.*; Ewig, F.*; Funke, F.*; Hidaka, Akihide; Gauntt, R.*; et al.

NEA/CSNI/R(99)7, p.311 - 325, 1999/00

Production of elemental iodine from radioactive methyl iodide under sunlight

; ;

Journal of Nuclear Science and Technology, 16(7), p.527 - 530, 1979/00

https://doi.org/10.3327/jnst.16.527

no abstracts in English

Influence of iodine chemistry in accumulated water at reactor buildings on late phase source term at Fukushima NPP accident

Hidaka, Akihide

no journal, , 

During core cooling at Fukushima Daiichi NPP accident, large amount of contaminated water was accumulated in the basements of reactor buildings at Units 1 to 4. The estimated ratios of I and Cs quantities in water to the core inventories are 0.51%, 0.85% at Unit 1, 74%, 38% at Unit 2 and 26%, 18% at Unit 3, respectively. According to the Henry's law, certain fraction of iodine in water could be released to atmosphere. Many evaluations for I-131 release have been performed so far by MELCOR or the reverse estimation with SPEEDI. The SPEEDI reverse predicted significant release until March 26 while no prediction in MELCOR after March 17. The present study showed that iodine release from accumulated water due to radiolytic conversion from I to I and gas-liquid partition of I may explain the release between March 17 and 26. This strongly suggests a need for improvement of current MELCOR approach which treats the release only from containment breaks.

A Sensitivity analysis of the iodine production using a reaction kinetics dataset

Zablackaite, G.; Shiotsu, Hiroyuki; Zheng, X.; Kido, Kentaro

no journal, ,