Thermal hydraulic analysis of the JMTR improved LEU-core

Tabata, Toshio; Nagao, Yoshiharu; Komukai, Bunsaku; Naka, Michihiro; Takeda, Takashi*; Fujiki, Kazuo

JAERI-Tech 2002-100, 108 Pages, 2003/01

JAERI-Tech-2002-100.pdf:4.44MB

After the investigation of the new core arrangement for the JMTR reactor in order to enhance the fuel burn-up and consequently extend the operation period, the "improved LEU core" that utilized 2 additional fuel elements instead of formerly installed reflector elements, was adopted. This report describes the results of the thermal-hydraulic analysis of the improved LEU core as a part of safety analysis for the licensing. The analysis covers steady state, abnormal operational transients and accidents, which were described in the annexes of the licensing documents as design bases events. Calculation conditions for the computer codes were conservatively determined based on the neutronic analysis results and others. The results of the analysis, that revealed the safety criteria were satisfied on the fuel temperature, DNBR and primary coolant temperature, were used in the licensing. The operation license of the JMTR with the improved LEU core was granted in March 2001, and the reactor operation with new core started in November 2001 as 142nd operation cycle.

Measurement of coolant flow in fuel elements at the JRR-4 silicide fuel core

Yamamoto, Kazuyoshi; Watanabe, Shukichi; Nagatomi, Hideki; Kaminaga, Masanori; Funayama, Yoshiro

JAERI-Tech 2002-034, 40 Pages, 2002/03

JAERI-Tech-2002-034.pdf:1.97MB

JRR-4, a swimming-pool type research reactor with a thermal power of 3.5MW, attained criticality in July 1998, after replacing its 90% enrichment fuel with a 20% enrichment fuel under the Reduced Enrichment Program. As a part of the program, safety analysis on thermo-hydraulics of the reactor core was conducted on cases including single channel blockage accident. With the conclusion that a certain margin on thermo-hydraulics was necessary, investigation and experiments were carried out with an aim to increase the core flow rate. To increase the core flow, it was carried out to reduce the bypass flow in the core and to increase the primary coolant flow rate from 7m/min to 8m/min. After flow measurements using a mock-up fuel element, flow velocity of the fuel channel was determined as 1.45m/s as opposed to the designed value of 1.44m/s, and the ratio of core flow to total flow was 0.88, exceeding the value 0.86 used for the safety analysis.This report describes the JRR-4 core flow increase plan as well as the results of the channel flow rate measurement

Feasibility study for improvement of efficient irradiation with LEU core in JMTR

Naka, Michihiro; Nagao, Yoshiharu; Komukai, Bunsaku; Tabata, Toshio

Proceedings of 7th Meeting of the International Group on Research Reactors (IGORR-7) (CD-ROM), 7 Pages, 1999/10

no abstracts in English

Decrease in coolability events analysis for the safety assessment of JRR-3 silicide core by THYDE-W code

Kaminaga, Masanori; Yamamoto, Kazuyoshi

JAERI-Tech 97-016, 120 Pages, 1997/03

JAERI-Tech-97-016.pdf:3.76MB

no abstracts in English

Reactivity initiated events analysis for the safety assessment of JRR-3 silicide core by EUREKA-2 code

Kaminaga, Masanori

JAERI-Tech 97-014, 125 Pages, 1997/03

JAERI-Tech-97-014.pdf:4.04MB

no abstracts in English

Reactivity initiated events analysis for the safety assessment of JRR-4 silicide LEU core

Kaminaga, Masanori; Yamamoto, Kazuyoshi; Watanabe, Shukichi; Nakano, Yoshihiro

JAERI-Tech 95-040, 79 Pages, 1995/07

JAERI-Tech-95-040.pdf:2.25MB

no abstracts in English

Study on the reliability of silicide fuels at elevated temperatures

Yanagisawa, Kazuaki;

Proc. of 4th Asian Symp. on Research Reactors; ASRR-IV, p.58 - 69, 1993/00

no abstracts in English

Neutronics design of JMTR-LEU core

Nagaoka, Yoshiharu; Komukai, Bunsaku; ; Koike, Sumio; Saito, Minoru;

JAERI-M 92-098, 81 Pages, 1992/07

JAERI-M-92-098.pdf:1.81MB

no abstracts in English

Nuclear hot spot factor of JMTR-LEU core

Nagaoka, Yoshiharu; Komukai, Bunsaku; ; Saito, Minoru;

JAERI-M 92-042, 92 Pages, 1992/03

JAERI-M-92-042.pdf:2.18MB

no abstracts in English

Progress in safety evaluation for the JMTR core conversion to LEU fuel

; ; Saito, Junichi; Komukai, Bunsaku; Ando, Hiroei; ; ; ; Saito, Minoru;

Proc. on 12th Int. Meeting,Reduced Enrichment for Research and Test Reactors, p.269 - 280, 1991/00

no abstracts in English