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Journal Articles

Study on operation scenario of tritium production for a fusion reactor using a high temperature gas-cooled reactor

Kawamoto, Yasuko*; Nakaya, Hiroyuki*; Matsuura, Hideaki*; Katayama, Kazunari*; Goto, Minoru; Nakagawa, Shigeaki

Fusion Science and Technology, 68(2), p.397 - 401, 2015/09

Times Cited Count：1 Percentile：8.93(Nuclear Science & Technology)

To start up a fusion reactor, it is necessary to provide a sufficient amount of tritium from an external device. Herein, methods for supplying a fusion reactor with tritium are discussed. Use of a high temperature gas cooled reactor (HTGR) as a tritium production device has been proposed. So far, the analyses have been focused only on the operation in which fuel is periodically exchanged (batch) using the block type HTGR. In the pebble bed type HTGR, it is possible to design an operation that has no time loss for refueling. The pebble bed type HTGR (PBMR) and the block type HTGR (GTHTR300) are assumed as the calculation and comparison targets. Simulation is made using the continuous-energy Monte Carlo transport code MVPBURN. It is shown that the continuous operation using the pebble bed type HTGR has almost the same tritium productivity compared with the batch operation using the block type HGTR. The issues for pebble bed type HTGR as a tritium production device are discussed.

Journal Articles

Development of simple method to incorporate out-of-core cooling effect on thorium conversion in multi-pass fueled reactor and investigation on characteristics of the effect

Fukaya, Yuji

Annals of Nuclear Energy, 81, p.301 - 305, 2015/07

https://doi.org/10.1016/j.anucene.2015.03.005

Times Cited Count：1 Percentile：8.93(Nuclear Science & Technology)

Development of a simple method to incorporate the out-of-core cooling effect on the thorium conversion in multi-pass fueled reactors and investigation on characteristics of the effect have been performed. For multi-pass fueled reactors, such as Molten Salt Breeder Reactor (MSBR) and Pebble-Bed Modular Reactor (PBMR), fuel moves in the core and exits from the core. The nuclides decay also out of the core, and it should be also considered if it is important for core characteristics. In the present study, $^{233}$ Pa is considered to evaluate the thorium conversion accurately. To take the effect into account, in the present study, an effective decay constant is proposed to make equilibrium concentration of $^{233}$ Pa without out-of-core cooling equal to that of out-of-core cooling. With the effective decay constant, the out-of-core cooling effect can be incorporated even with the code system using macroscopic cross sections generated by cell burn-up calculations without any code modification. In addition, the characteristic of out-of-core cooling effect for the thorium conversion is evaluated for thorium fueled reactors of MSBR and PBMR. It is concluded that the out-of-core cooling effect is suitable for MSBR to enhance thorium conversion because of the fast flow rate of fuel salt. On the other hand, the effect is not important and not realistic to employ for PBMR because the in-core residence time of approximately 100 days is longer than the half-life of $^{233}$ Pa of 27.0 days, and the effect cannot improve the conversion ratio drastically.

Journal Articles

Fusion power reactor designs adopting SiC/SiC composite as the structural material

Nishio, Satoshi

Purazuma, Kaku Yugo Gakkai-Shi, 80(1), p.14 - 17, 2004/01

https://doi.org/10.1585/jspf.80.14

SiC/SiC composite is a promising structural material candidate for fusion power cores and has been considered internationally in several power plant studies. It offers safety advantages arising from its low induced radioactivity and afterheat, and the possibility of high efficiency of energy conversion through high temperature operation. The latest SiC/SiC-based power core design studies are summarized, and the key SiC/SiC parameters affecting the performance of power core components are highlighted.

Journal Articles