Calculation of decay heat by new ORIGEN libraries for high temperature engineering test reactor

Simanullang, I. L.* ; Honda, Yuki; Fukaya, Yuji   ; Goto, Minoru  ; Shimazaki, Yosuke ; Fujimoto, Nozomu*; Takada, Shoji

Decay heat of the High Temperature Engineering Test Reactor had been evaluated by the Shure Equation and/or ORIGEN code based on the LWR's data. However, to evaluate more accurately, a suitable method must be considered because of the differences neutron spectrums from the LWRs. Therefore, the decay heat and the generated nuclides for the neutron spectrums of the core with different graphite moderator amount were calculated by the ORIGEN2 code. As a result, it is clear that the calculated decay heats are similar value with LWRs for about one year after the reactor shutdown, and that the significant differences are observed on the longer period affected by the generated nuclides such as Y, Cs, Pr, Rh, Am etc. It is also clear that the dose is affected by Pu on the initial stage after the reactor shutdown.