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Tsujimura, Norio; Yoshida, Tadayoshi; Sanada, Yukihisa
JPS Conference Proceedings (Internet), 24, p.011013_1 - 011013_6, 2019/01
Nomura, Yasushi; Okuno, Hiroshi
Nihon Genshiryoku Gakkai-Shi, 35(2), p.155 - 163, 1993/02
no abstracts in English
Aizawa, Eiju; Yamane, Yuichi
no journal, ,
TRACY (Transient experiment critical facility) is a reactor to perform supercritical experiments using low-enriched uranyl nitrate aqueous solution. In a supercritical experiment, up to 3$ of reactivity is inserted by withdrawing a control rod, called "transient rod," from the center of the core tank or feeding fuel solution into the core tank.Since 1996, TRACY supercritical experiments have been performed and transient data such as power, temperature and pressure have been measured and evaluated. Furthermore, we have developed a system to observe solution behavior under criticality accident condition for the elucidation of transient events. Those experiences we have gained through the TRACY experiments will be presented at the lecture in the 46th reactor physics summer seminar of the Atomic Energy Society of Japan.
Miyoshi, Yoshinori
no journal, ,
The Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF) is one of the largest research facilities in JAEA. Multipurpose research and development of advanced technology have been made particularly on the reprocessing technology and trans-uranium waste management. This report introduces the criticality safety experiments with the STACY and TRACY. Since the accident in Fukushima Daiichi Nuclear Power Station in March 2011, it became necessary to reevaluate the safety license of many research facilities such as research reactor, critical facility, fuel treatment facility. In NUCEF, reassessment of the modification program of STACY from fuel solution-type to fuel rod-type is on going. This report mainly presents the principle and technical issues of safety reassessment of the STACY modification based on the new regulatory requirements.
Yoshida, Ryoichiro; Yamane, Yuichi; Abe, Hitoshi
no journal, ,
At criticality accident on solution fuel, it is known that hydrogen gas is generated with nuclear fission. Because of the temporary decrease effect on power through density decrease and the possibility which causes secondary accident such as explosion, it is important on safety evaluation at criticality accident that to estimate relating the amount of hydrogen gas and the number of nuclear fissions. The time history data of concentration of hydrogen gas in vent gas when the transition critically used uranyl nitrate solution, which was obtained from Transient Experiment Critical Facility (TRACY), could not be explained by simple diffusion, because of peak about 500 seconds later from reactivity addition and after that long tail. Then, calculating the transition behavior of hydrogen gas in reactor core tank by combining multiple models such as Taylor dispersion, and evaluating concentration of hydrogen gas result reproducing the measured value well. The amount of hydrogen gas also evaluated 4 mol per 10
fissions.
