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Kurata, Masaki; Osaka, Masahiko; Jacquemain, D.*; Barrachin, M.*; Haste, T.*
Advances in Nuclear Fuel Chemistry, p.555 - 625, 2020/00
The importance of fuel chemistry has been revivaled since Fukushima-Daiichi Nuclear Power Station (FDNPS) accident. The inspection and analysis of damaged three units, which had been operated in March 11, 2011, showed large differences in the accident progression sequence for these units, because operators attempted to prevent or mitigate the accident progression of each unit by all means possible. Characteristics of fuel debris are considered to be largely influenced by the difference in the sequence and, hence, deviated from those predicted from prototypic accident scenarios, which had been mainly identified from the analysis of Three Mile Island-2 (TMI-2) accident and the following sim-tests. For the proper improvement of our knowledge on severe accident (SA), including non-prototypic conditions, one has to start improving the phenomenology of fuel/core degradation and fission product (FP) behavior. Advances in the chemistry is the most essential approach. The present review attempts to focus on the recent updates and remaining concerns after the FDNPS accident.
Uchibori, Akihiro; Ohshima, Hiroyuki
Advances in Nuclear Fuel, p.53 - 72, 2012/02
A numerical analysis method for melting/solidification phenomena has been developed to evaluate a feasibility of several candidate techniques in the nuclear fuel cycle. Our method is based on the eXtended Finite Element Method (X-FEM) which has been used for moving boundary problems. In this study, a method to solve multi-dimensional problems involving liquid-phase flows was newly constructed. The numerical solutions of the one-dimensional Stefan problem, solidification in a two-dimensional square corner and melting of pure gallium are compared to the exact solutions or to the experimental data. Through these analyses, validity of the newly developed numerical analysis method has been demonstrated.
Yamane, Yuichi
Advances in Nuclear Fuel, p.159 - 174, 2012/02
The aim of the chapter is to introduce a concept of new method developed to evaluate the number of fission in a criticality accident, which is expected to give reasonable value, not too much overestimated, i.e. the estimated value is in the almost same order as the actual value. The 1st section introduces the phenomena of the criticality accident with uranyl nitrate solution based on the TRACY experiment, which has been conducted by Japan Atomic Energy Agency. In the 2nd section, the condition characterizing a criticality accident is considered, such as temperature, reactivity temperature coefficient, water, cooling, etc. In the 3rd section, a new simplified method to evaluate the total fission number is described. In the 4th section, the new developing method is applied to some case to see its applicability.
Asakura, Toshihide; Hotoku, Shinobu; Ban, Yasutoshi; Matsumura, Masakazu*; Kim, S.-Y.; Mineo, Hideaki; Morita, Yasuji
Proceedings of International Conference ATALANTE 2004 Advances for Future Nuclear Fuel Cycles, 5 Pages, 2004/06
In JAERI, PARC process based on PUREX technique has been studied to as the basis of future reprocessing. The key of concept is to obtain the products, U and Pu, within only a single extraction cycle by separating Np and Tc from U and Pu before U/Pu partition. Two flow-sheet tests on the process were performed with 44 GWd/t PWR spent-fuel solutions. It was demonstrated that remaining Np in raffinate from co-extraction could be decreased to 13 % compared to the dissolver solution with increased solvent flow rate and with increased nitric acid concentration of FP scrubbing solution. It was demonstrated that Np separation (selective reduction by n-butyraldehyde) efficiency could be improved from 36 % to 78 % by flow-sheet modification; increasing reductant concentration and scrubbing solution flow rate. The feasibility of the Tc separation technique by high acid scrubbing was demonstrated.
Suzuki, Shinichi; Sasaki, Yuji; Yaita, Tsuyoshi; Kimura, Takaumi
Proceedings of International Conference ATALANTE 2004 Advances for Future Nuclear Fuel Cycles (CD-ROM), 4 Pages, 2004/06
An innovative chemical separation process (ARTIST: Amide-based Radio-resources Treatment with Interim Storage of Transuranics) was proposed for the treatment of spent nuclear fuel. The main concept of ARTIST process is to recover and stock all actinides (An) and to dispose the fission products (FP). One of the main purposes of this process is selective isolation of uranium. Since the brached alkyl type N,N-dialkyl-monoamides (BAMA) have the steric hindrance on the complexation with metal cations, BAMA can be used to separate An(VI) from An(IV). N,N-di-(2-ethyl)hexyl-2,2-dimethylpropanamide (D2EHDMPA) can recover U(VI) selectively without accumulating Pu(IV) in uranium isolation process. From extraction behavior of Np, D2EHDMPA can extract and separate U(VI) from Np(VI) without reduction from Np(VI) to Np(V) or Np(IV).
Sasaki, Yuji; Sugo, Yumi; Suzuki, Hideya*; Kimura, Takaumi
Proceedings of International Conference ATALANTE 2004 Advances for Future Nuclear Fuel Cycles (CD-ROM), 4 Pages, 2004/06
no abstracts in English
Arai, Yasuo; Pillon, S.*
Proceedings of International Conference ATALANTE 2004 Advances for Future Nuclear Fuel Cycles (CD-ROM), 9 Pages, 2004/06
no abstracts in English
Ozawa, Masaki; *
Proceedings of International Conference ATALANTE 2004 Advances for Future Nuclear Fuel Cycles (CD-ROM), 69 Pages, 2004/06
None
Namba, Takashi; Funasaka, Hideyuki; Nagaoki, Yoshihiro; Sagayama, Yutaka
Proceedings of International Conference ATALANTE 2004 Advances for Future Nuclear Fuel Cycles (CD-ROM), 0 Pages, 2004/00
Experimental Study on Temperature Fluctuation Phenomena at T-pipe Junction(6)
Yamaguchi, Takashi; Shuji, Yoshiyuki;
Proceedings of ANS Topical Meeting on Advances in Nuclear Fuel Management II, 0 Pages, 1997/00
None
