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Di Lemma, F. G.; Nakajima, Kunihisa; Yamashita, Shinichiro; Osaka, Masahiko
Journal of Nuclear Materials, 484, p.174 - 182, 2017/02
Times Cited Count：22 Percentile：90.44(Materials Science, Multidisciplinary)Chemisorption phenomena can affect fission products retention in the nuclear reactor vessel during a Severe Accident (SA). This paper will describe the influence of molybdenum contained in type 316 stainless steel (SS) on Cs chemisorption. Our experiments showed the formation of Cs-Mo compounds in addition to CsFeSiO
, observed previously on SS304. The results of high temperature stability tests on the deposits are also presented. These tests aimed at simulating the revaporization of FP from structural materials during a SA. From our results, it can be inferred that Cs-Mo deposits may revaporize, contributing as a delayed source to the radioactive release.
Hidaka, Akihide; Sugimoto, Jun; Muramatsu, Ken; *; *
PSA95: Proc. of Probabilistic Safety Assessment Methodology and Applications, 1, p.241 - 246, 1995/00
no abstracts in English
Di Lemma, F. G.; Nakajima, Kunihisa; Yamashita, Shinichiro; Osaka, Masahiko; Nagase, Fumihisa
no journal, ,
This work will compare the microstructural results obtained from different Cs-chemisorbed stainless steel (SS) samples (SS304 and modified-SS316). The analyses showed that Cs-chemisorption was influenced by the presence of different minor elements in SS (such as Si and Mo), as the deposits on the different samples exhibited different properties.
Karasawa, Hidetoshi; Miwa, Shuhei; Kino, Chiaki*
no journal, ,
Amount of CsOH chemisorbed on surfaces of structural materials such as separators and dryers in unit1, unit2, unit3 were evaluated by the SAMPSON code under the Fukushima Daiichi Nuclear Power Plant severe accident conditions. Concentrations of CsOH vapors are decreased due to reaction with Mo vapors and to produce aerosols under decreasing gas temperature. As an existing chemisorption model is independent on CsOH concentrations, an ECUME has developed a new chemisorption model with a function of CsOH concentrations and gas temperature. Cs absorbed amounts were changed unit by unit due to different CsOH concentrations and gas temperature. Evaluation of CsOH chemisorption in a SA analysis needs the new chemisorption model with dependency of CsOH concentrations.
Karasawa, Hidetoshi; Miwa, Shuhei; Suzuki, Eriko; Nakajima, Kunihisa; Kino, Chiaki*
no journal, ,
Temperature effects of chemisorption of CsOH vapor generated at about 1000K on SUS were examined using TeRRa test apparatus with temperature gradient tube from 1273K to 473K. The chemisorption amounts were measured using IPS after dissolving test coupons. These results were calculated using the SA code, SAMPSON. For the test analysis, the thermal hydraulic analysis (THA) module and the FP transport analysis (FPTA) module were used. The FPTA could calculated the chemisorption amount within the experimental error range using the gas temperature calculated by the THA module. So the temperature dependency of the chemisorption model used in the calculation was validated.
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.
