Probabilistic risk assessment method development for high temperature gas-cooled reactors, 2; Development of accident sequence analysis methodology

Matsuda, Kosuke*; Muramatsu, Ken*; Muta, Hitoshi*; Sato, Hiroyuki; Nishida, Akemi; Ohashi, Hirofumi; Itoi, Tatsuya*; Takada, Tsuyoshi*; Hida, Takenori*; Tanabe, Masayuki*; et al.

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04

This paper proposes a set of procedures for accident sequence analysis in seismic PRAs of HTGRs that can consider the unique accident progression characteristics of HTGRs. Main features of our proposed procedure are as follows: (1) Systematic analysis techniques including Master Logic Diagrams are used to ensure reasonable completeness in identification of initiating events and classification of accident sequences, (2) Information on factors that govern the accident progression and source terms are effectively reflected to the construction of event trees for delineation of accident sequences, and (3) Frequency quantification of seismically-initiated accident sequence frequencies that involve multiplepipe ruptures are made with the use of the Direct Quantification of Fault Trees by Monte Carlo (DQFM) method by a computer code SECOM-DQFM.

Annual report for FY2005 on the activities of Department of Radiation Protection; April 1, 2005 - March 31, 2006

Murakami, Hiroyuki; Mizushita, Seiichi; Yoshizawa, Michio; Yamamoto, Hideaki; Yamaguchi, Takenori; Yamaguchi, Yasuhiro

JAEA-Review 2006-032, 181 Pages, 2006/11

JAEA-Review-2006-032.pdf:45.0MB

This annual report describes the activities of Department of Radiation Protection in Nuclear Science Research Institute in the fiscal year 2005. The report covers environmental monitoring around the facilities, radiation protection of workplace and workers, individual monitoring, maintenance of monitoring instruments, and research and development of radiation protection technologies, which were performed at Nuclear Science Research Institute, Tokai Research and Development Center, Japan Atomic Energy Agency. There were no occupational or public exposures exceeding the prescribed dose limits. No effluent releases were recorded exceeding the prescribed limits on the amount and concentration of radioactivity for gaseous release and liquid waste. As for the research and development activities, studies were conducted focusing mainly on the following themes: technological developments on operational radiation protection and establishment of calibration fields for various types of neutrons.

Analysis using MCNP 4A of critical experiments at TCA for integral evaluation of fission product nucleus neutron cross sections; Preparation of benchmark problems

Sakurai, Kiyoshi; Arakawa, Takuya*; Yamamoto, Toshihiro; Komuro, Yuichi; Suzaki, Takenori; ; Nitta, Kazuo*; Horiki, Oichiro*

JAERI-Research 96-067, 41 Pages, 1996/12

JAERI-Research-96-067.pdf:1.04MB

no abstracts in English

Measurement of reactivity worths of natural Sm, Cs, Gd, Nd, Rh, Eu, B and Er

Komuro, Yuichi; ; Sakurai, Kiyoshi; Yamamoto, Toshihiro; Suzaki, Takenori; Horiki, Oichiro*; Nitta, Kazuo*

PHYSOR 96: Int. Conf. on the Physics of Reactors, 1, p.L120 - L129, 1996/00

no abstracts in English

Measurements and analyses of the ratio of U captures to U fission in low-enriched UO tight lattices

Nakajima, Ken; ; Yamamoto, Toshihiro; ; Suzaki, Takenori

Journal of Nuclear Science and Technology, 31(11), p.1160 - 1170, 1994/11

https://doi.org/10.3327/jnst.31.1160

no abstracts in English

Am-241 sample reactivity experiments in TCA, 1; Measurement results and evaluation of uncertainty in calculation caused by nuclear data uncertainty

Sakurai, Takeshi; Mori, Takamasa; Suzaki, Takenori*; Okajima, Shigeaki; Ando, Yoshihira*; Yamamoto, Toru*

no journal, , 

Measurement and analysis have been made for the reactivity worth of Am-241 oxide sample(23 g) in water-moderated low-enriched UO fuel lattices with water-to-fuel volume ratios ranging from 0.56 to 3.0 at TCA of JAEA to validate the capture cross section of Am-241 of thermal to resonance energy region in current nuclear data library. The reactivity worth of sample at the core center was measured with uncertainty of 0.4% 2.1%. The analysis was made by using the continuous energy Monte Carlo transport code MVP with JENDL-3.3 nuclear data. The reactivity worth was calculated from difference of effective multiplication factors and was obtained with statistical uncertainties of 0.6% 1.1%. The calculation underestimated the measurement by 4% 9%. Furthermore, an evaluation was made for the uncertainty in calculation caused by nuclear data uncertainty to investigate the present discrepancy between calculation and measurement.

Research on advanced fuel element for upgrading safety of high temperature gas-cooled reactors, 4; Modeling for casting oxidation resistant fuel element reactors

Kuroda, Masatoshi*; Tojo, Takuya*; Yamamoto, Takenori*; Aihara, Jun; Tachibana, Yukio

no journal, , 

High temperature gas-cooled reactor (HTGR) is a fourth generation nuclear reactor with inherent safety. In recent years, fuel elements with oxidation resistance has been developed for use in HTGR. In order to maintain the structural integrity of the oxidation resistant fuel element under accident conditions, a technique to fabricate a high-strength fuel should be required. In the present study, hot pressing conditions have been considered as the parameters which affect the strength of the oxidation resistant fuel compact, and a model has been created to predict the strength of the fuel compact from the hot pressing conditions by applying statistical approaches. The hot pressing conditions which can fabricate the high-strength oxidation resistant fuel element were also predicted by the model.