Development of evaluation method for variability of groundwater flow conditions associated with long-term topographic change and climate perturbations

Onoe, Hironori; Kosaka, Hiroshi*; Matsuoka, Toshiyuki; Komatsu, Tetsuya; Takeuchi, Ryuji; Iwatsuki, Teruki; Yasue, Kenichi

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.3 - 14, 2019/06

https://doi.org/10.3327/jnuce.26.1_3

In this study, it is focused on topographic changes due to uplift and denudation, also climate perturbations, a method which is able to assess the long-term variability of groundwater flow conditions using the coefficient variation based on some steady-state groundwater flow simulation results was developed. Spatial distribution of long residence time area which is not much influenced due to long-term topographic change and recharge rate change during the past one million years was able to estimate through the case study of the Tono area, Central Japan. By applying this evaluation method, it is possible to identify the local area that has low variability of groundwater flow conditions due to topographic changes and climate perturbations from the regional area quantitatively and spatially.

OECD/NEA,SCORPIO-VVER project; Enhancement of VVER-type power plant core monitoring function

Kosaka, Atsuo; Suzudo, Tomoaki

JAERI-Review 99-012, 22 Pages, 1999/03

JAERI-Review-99-012.pdf:1.1MB

no abstracts in English

Development of reconstitution technique of irradiated specimen; Progress report for FY1993 on cooperated research between JAERI and IHI

Onizawa, Kunio; Fukaya, Kiyoshi; Nishiyama, Yutaka; Suzuki, Masahide; Shibata, Katsuyuki; Kosaka, Atsuo; Kaihara, Shoichiro*; Nakamura, Terumi*; Sato, Akira*; Yoshida, Kazuo*; et al.

JAERI-Tech 94-017, 58 Pages, 1994/09

JAERI-Tech-94-017.pdf:2.74MB

Regulatory codes require the surveillance test to evaluate the irradiation embrittlement of reactor pressure vessel during operation. However , it is anticipated that the number of those specimens is insufficient in case plant life is extended. Reconstitution techniques by electron beam weld, laser weld, arc stud weld as well as surface-activated joining (SAJ) have been investigated for the re-use of un-deformed parts from tested Charpy impact specimen. The important items for the reconstitution technique are to reduce the width of heat affected zone to maximize the material available, and to lower the maximum temperature of specimen during joining process to preclude the recovery of radiation damage. SAJ can be achieved from a removal pf surface contamination by rotating one-side specimen in vacuum with applying modest friction force. Therefore, SAJ method is expected to be suitable for specimen reconstitution in view of material heating and melting. This paper describes preliminary study to develop Charpy specimen reconstitution technique using reactor pressure vessel steel, A533B-1, by SAJ method. Test results showed that the SAJ method had a capability of joining affected zone less than 1.5mm in half width, and over-temperature region less than 3 mm in half width above reactor operating temperature during joining. It was also found that transition temperature from reconstituted Charpy specimen could be evaluated.

Major topics of LWR safety research in Japan

Ichikawa, Michio; Kosaka, Atsuo;

Proc. of the 9th Pacific Basin Nuclear Conf., Vol. 2, 0, p.583 - 588, 1994/00

no abstracts in English

Results of piping reliability test program at JAERI

Shibata, Katsuyuki; Isozaki, Toshikuni; ; Kurihara, Ryoichi; Onizawa, Kunio; Kosaka, Atsuo

Proc. of 6th German-Japanese Seminar on Structural Strength and NDE Problems in Nuclear Engineering, 19 Pages, 1993/00

no abstracts in English

Analysis of LaSalle-2 neutron flux oscillation event with RETRAN code

Araya, Fumimasa; Hirano, Masashi; ; Matsumoto, Kiyoshi; Yokobayashi, Masao; Kosaka, Atsuo

Nihon Genshiryoku Gakkai-Shi, 34(6), p.565 - 575, 1992/06

https://doi.org/10.3327/jaesj.34.565

no abstracts in English

Description of code system PLES/PTS for evaluation of pressure vessel integrity during PTS events

Hirano, Masashi; Kosaka, Atsuo

JAERI-M 92-006, 76 Pages, 1992/02

JAERI-M-92-006.pdf:1.53MB

no abstracts in English

IDAS-RR, an Incident data base system for research reactors; Users manual

Matsumoto, Kiyoshi; Kosaka, Atsuo; Kaminaga, Masanori; Murayama, Yoji; Onishi, Nobuaki;

JAERI-M 90-055, 232 Pages, 1990/03

JAERI-M-90-055.pdf:5.32MB

no abstracts in English

Statistical method application to knowledge base building for reactor accident diagnostic system

; Yokobayashi, Masao; Matsumoto, Kiyoshi; Kosaka, Atsuo

Journal of Nuclear Science and Technology, 26(11), p.1002 - 1012, 1989/11

https://doi.org/10.3327/jnst.26.1002

no abstracts in English

A Simulation of steam generator tube rupture accident by safety analysis code RELAP5/Mod1

; ; ; Fujiki, Kazuo; Kosaka, Atsuo;

Tech. Rep. Inst. At. Energy,Kyoto Univ., 211, p.1 - 57, 1989/05

no abstracts in English