Dissolutions of oxide dispersion strengthened ferritic steels in various nitric acid solutions; Martensitic 9Cr-ODS steels

Inoue, Masaki; Ikeuchi, Hirotomo; Takeuchi, Masayuki; Koyama, Shinichi; Suto, Mitsuo

JAEA-Research 2011-057, 100 Pages, 2012/03

JAEA-Research-2011-057.pdf:3.23MB

Corrosion resistance of fuel pin cladding tube materials is one of the most important properties to design aqueous reprocessing process. The martensitic oxide dispersion strengthened ferritic steel, names as "9Cr-ODS" steel, is the primary candidate of high burnup fuel pin cladding tube for fast reactor cycle. Because 9Cr-ODS steel contains lower chromium than stainless steels, oxidizing species in nitric acid medium needs to reduce its corrosion rate. In spent fuel dissolvers, although both nitric acid and metallic ions concentrations change, corrosion potential of 9Cr-ODS steel tends to increase gradually and stabilize protective passive layer effectively.

Annular core experiments in HTTR's start-up core physics tests

Fujimoto, Nozomu; Yamashita, Kiyonobu*; Nojiri, Naoki; Takeuchi, Mitsuo; Fujisaki, Shingo; Nakano, Masaaki*

Nuclear Science and Engineering, 150(3), p.310 - 321, 2005/07

https://doi.org/10.13182/NSE03-79

Annular cores were formed in startup-core-physics tests of the High Temperature Engineering Test Reactor (HTTR) to obtain experimental data for verification of calculation codes. The first criticality, control rod positions at critical conditions, neutron flux distribution, excess reactivity etc. were measured as representative data. These data were evaluated with Monte Carlo code MVP that can consider the heterogeneity of coated fuel particles (CFP) distributed randomly in fuel compacts directly. It was made clear that the heterogeneity effect of CFP on reactivity for annular cores is smaller than that for fully-loaded cores. Measured and calculated effective multiplication factors (k) were agreed with differences less than 1%k. Measured neutron flux distributions agreed with calculated results. The revising method was applied for evaluation of excess reactivity to exclude negative shadowing effect of control rods. The revised and calculated excess reactivity agreed with differences less than 1%k/k.

Development of measurement technique of large negative reactivity by an inverse kinetics rod drop method

Takahashi, Hiroyuki; Takeuchi, Mitsuo; Murayama, Yoji

JAERI-Tech 2001-072, 58 Pages, 2001/11

JAERI-Tech-2001-072.pdf:2.89MB

no abstracts in English

Start up core physics tests of High Temperature Engineering Test Reactor (HTTR), 2; First criticality by an annular form fuel loading and its criticality prediction method

Fujimoto, Nozomu; Nakano, Masaaki*; Takeuchi, Mitsuo; Fujisaki, Shingo; Yamashita, Kiyonobu

Nihon Genshiryoku Gakkai-Shi, 42(5), p.458 - 464, 2000/05

https://doi.org/10.3327/jaesj.42.458

no abstracts in English

First criticality prediction of the HTTR by 1/M interposition method

Fujimoto, Nozomu; Nakano, Masaaki*; Nojiri, Naoki; Takeuchi, Mitsuo; Fujisaki, Shingo; Yamashita, Kiyonobu

JAERI-Conf 99-006, p.328 - 333, 1999/08

https://jopss.jaea.go.jp/pdfdata/JAERI-Conf-99-006.pdf

no abstracts in English

Measurement of control rod reactivity worth with long insertion time by inverse kinetics rod drop method

Yamashita, Kiyonobu; Takeuchi, Mitsuo; Fujimoto, Nozomu; Fujisaki, Shingo; Nakano, Masaaki*; Nojiri, Naoki; Tamura, Seiji*

Nihon Genshiryoku Gakkai-Shi, 41(1), p.35 - 38, 1999/00

https://doi.org/10.3327/jaesj.41.35

no abstracts in English

Preliminary analyses for HTTR's start-up physics tests by Monte Carlo code MVP

Nojiri, Naoki; Nakano, Masaaki; Ando, Hiroei; Fujimoto, Nozomu; Takeuchi, Mitsuo; Fujisaki, Shingo; Yamashita, Kiyonobu

JAERI-Tech 98-032, 59 Pages, 1998/08

JAERI-Tech-98-032.pdf:2.48MB

no abstracts in English

Analytical estimation of control rod shadowing effect for excess reactivity measurement of high temperature engineering test reactor (HTTR)

Nakano, Masaaki; Yamashita, Kiyonobu; Fujimoto, Nozomu; Nojiri, Naoki; Takeuchi, Mitsuo; Fujisaki, Shingo; ; Nakata, Tetsuo*

JAERI-Tech 98-017, 61 Pages, 1998/05

JAERI-Tech-98-017.pdf:2.68MB

no abstracts in English

Benchmark problems of start-up core physics of High Temperature engineering Test Reactor (HTTR)

Yamashita, Kiyonobu; Nojiri, Naoki; Fujimoto, Nozomu; Nakano, Masaaki*; Ando, Hiroei; Nagao, Yoshiharu; Nagaya, Yasunobu; Akino, Fujiyoshi; Takeuchi, Mitsuo; Fujisaki, Shingo; et al.

Proc. of IAEA TCM on High Temperature Gas Cooled Reactor Applications and Future Prospects, p.185 - 197, 1998/00

no abstracts in English