Nuclear design of small-sized HTGR system (HTR50S)

Goto, Minoru  ; Seki, Yasuyoshi; Inaba, Yoshitomo  ; Ohashi, Hirofumi ; Sato, Hiroyuki  ; Fukaya, Yuji   ; Tachibana, Yukio 

Japan Atomic Energy Agency has started a conceptual design of a small-sized HTGR with 50 MW thermal power (HTR50S), which is a first-of-a-kind commercial or demonstration plant of a small-sized HTGR to be deployed in developing countries in the 2030s. The design policy of the HTR50S is to construct it without development of new technologies, which require additional demonstration tests, to suppress the construction cost and deploy it in 2030s. Accordingly, the nuclear design of the HTR50S was performed by upgrading the proven design technology of the High Temperature Engineering Test Reactor (HTTR). In the nuclear design of the HTR50S, we challenged to increase the power density and decrease the number of the fuel enrichments compared with the HTTR. As a result, the nuclear design was completed successfully by increasing the power density by 1.4 times of the power density of the HTTR and reducing the number of the fuel enrichment to only three from twelve of the HTTR.