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bus FP results and single effect testingKnebel, K.*; Jokiniemi, J.*; Bottomley, D.
Journal of Nuclear Science and Technology, 56(9-10), p.772 - 789, 2019/09
Times Cited Count：7 Percentile：58.58(Nuclear Science & Technology)Revaporisation of the fission products deposited in the primary circuit of a reactor was identified as a possible late source of fission product release during a severe accident: eg. loss of coolant accident (LOCA). Subsequent testing has shown that revaporisation is very likely to occur given a breach of the reactor and is an important contributor for the source term release to the containment and biosphere. The first part reviews the revaporisation mechanisms of Cs and other volatile or semi-volatile fission products transported in the primary circuit that were derived from the Phebus FP and associated programmes. The second part examines the separate effects testing to determine the high temperature chemistry ofvolatile and semi-volatile fission products (I, Mo, Ru) and structural materials (Ag, B) as well as atmospheric effects which substantially affect the source term. Finally, it examines Cs data from reactor accident sites that is providing additional knowledge of longer-term fission product chemistry. The results have been summarised in the form of a table and schematic diagram. This accumulated knowledge and experience has important applications to minimising contamination during decommissioning and site remediation techniques, as well as improving SA simulation codes and raising nuclear safety.
Suzuki, Eriko; Nakajima, Kunihisa; Osaka, Masahiko
Progress in Nuclear Science and Technology (Internet), 5, p.165 - 167, 2018/11
In severe accident condition, CsFeSiO could be formed by Cesium (Cs) chemisorption onto reactor structural materials. For evaluation of re-vaporization behavior, effect of atmosphere on the vaporization behavior of CsFeSiO at high temperature was investigated by thermal gravimetric-differential thermal analyzer (TG-DTA) experiments. As a result, it was found that vaporization of CsFeSiO in reducing atmosphere (Ar-5%H
) started at relatively low temperature, about 800
C, compared with in atmosphere containing HO (Ar-5%H-5%HO). It was inferred that a possible chemical reaction for the weight loss at around 800C would occurred by the decomposition of CsFeSiO into volatile Cs vapor species under H.
Shibazaki, Hiroaki*; Maruyama, Yu; Kudo, Tamotsu; Yuchi, Yoko; Chino, Eiichi; Nakamura, Hideo; Hidaka, Akihide; Hashimoto, Kazuichiro
JAERI-Conf 2000-015, p.225 - 230, 2000/11
no abstracts in English
Shibazaki, Hiroaki*; Maruyama, Yu; Kudo, Tamotsu; Hashimoto, Kazuichiro; Maeda, Akio; Harada, Yuhei; Hidaka, Akihide; Sugimoto, Jun
JAERI-Conf 99-005, p.191 - 196, 1999/07
no abstracts in English
Shibazaki, Hiroaki*; Maruyama, Yu; Kudo, Tamotsu; Hashimoto, Kazuichiro; Maeda, Akio; Harada, Yuhei; Hidaka, Akihide; Sugimoto, Jun
9th Int. Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-9)(CD-ROM), 13 Pages, 1999/00
no abstracts in English
Hidaka, Akihide; Maruyama, Yu; Shibazaki, Hiroaki*; Maeda, Akio; Harada, Yuhei; *; Yoshino, T.*; Sugimoto, Jun
JAERI-Tech 98-026, 83 Pages, 1998/07
no abstracts in English
Hidaka, Akihide; Igarashi, Minoru*; Hashimoto, Kazuichiro; ; *; Sugimoto, Jun
Heat and Mass Transfer in Severe Nuclear Reactor Accidents, 0, p.577 - 587, 1996/00
no abstracts in English
Hidaka, Akihide; *; Soda, Kunihisa; Muramatsu, Ken; Sakamoto, Toru*
ANS Proc. of the 1992 National Heat Transfer Conf., p.408 - 416, 1993/00
no abstracts in English
*; Muramatsu, Ken; Watanabe, Norio; *; *
Proc. of the Int. Topical Meeting on Safety of Thermal Reactors, 9 Pages, 1991/00
no abstracts in English
Miwa, Shuhei; Shinada, Masanori; Osaka, Masahiko; Sugiyama, Tomoyuki; Maruyama, Yu
no journal, ,
We performed the chemical reaction tests of BO
vapor/aerosol and Cs and I deposit using the apparatus which can simulate temperature conditions of reactor coolant system under a sever accident. The volatile I compounds were formed by the reaction of BO vapor/aerosol and deposit, and significant amount of I was revaporized from the deposit.
Nakajima, Kunihisa; Suzuki, Eriko; Osaka, Masahiko
no journal, ,
There are a large amount of stainless steels used for the reactor pressure vessel internals. So the cesium (Cs) deposition behavior might influence the Cs release and transport behaviors during severe light water reactor accidents. Thus, atmospheric effect on the Cs deposition behaviors onto stainless steels exposed to cesium hydroxide vapor was investigated. As the results, the Cs deposited amounts under oxidizing conditions such as mixed gas of argon, steam, and hydrogen (Ar-H-HO) were found to increase compared with those under the reducing condition of Ar-5%H. Furthermore, the cross-sectional observation of the Cs deposited layers by using a scanning electron microscope with an energy dispersive spectrometer suggested that revaporization of the deposited Cs occurred especially under the Ar-5%H reducing condition.
Kobata, Masaaki; Okane, Tetsuo; Nakajima, Kunihisa; Suzuki, Eriko; Kobayashi, Keisuke*; Osaka, Masahiko
no journal, ,
To Evaluate of re-evaporation behavior of Cs-Si-Fe-O compound formed by Cs chemisorption on the stainless steel under severe accident, HAXPES analysis was performed on the re-heated samples under various atmospheres. As a result, it was found that the re-heated samples under a reducing atmosphere, were changed to a Cs-Si-O compound with Fe desorption.
Karasawa, Hidetoshi; Miwa, Shuhei; Kino, Chiaki*
no journal, ,
Re-vaporization of CsOH in primary system was observed after a core shutdown in the Phebus FPT1 experiment. This behavior was examined using the SAMPSON code with the model of aerosol formation. The re-vaporization behavior was confirmed in the analysis, that is, deposited CsOH was evaporated when the vapor concentration became less than the saturated concentration and re-deposited in simulated steam generator walls with the lower temperature. As to FPs other than CsOH, the amount of each FP deposited in the simulated steam generator was found to be proportion to the FP component of aerosols as expected in the aerosol formation model.
