Study on TRU transmutation by LMFBRs,1; Study on FBR core concepts for TRU transmution

Yamaoka, Mitsuaki; Ishikawa, Makoto; Hayashi, Hideyuki; Wakabayashi, Toshio

A study was performed on TRU transmutation by LMFBRs. This report describes the results of the items shown below. (1) Study on a super long life core loaded with TRU. A feasibility study was performed on a super long life core loaded with TRU fuel which operates without fuel exchange during 30 years. Its advantage is that it can transmute TRU with storing it in the core during plant life time. I It was found that reactivity change and power variation due to burnup can be reduced remarkably by optimizing TRU loading amount and region. Also, it was found that a 1000 MWe core can transmute TRU of 10 ton which comes from 13 LWRs. (2) Study on a heterogeneous core loaded with TRU. The radial hderogeneous core is one of the candidate concepts for TRU transmutation because the internal blanket may be loaded with larger amount of TRU than the core fuel. It was found that the core loaded with large amount of TRU in the internal blanket can transmute TRU several times more than the homogeneous core with no significant in fluence on core characteristics. (3) Study on a method for TRU loading in a subassembly. A TRU loading method was studied where both TRU loaded fuel pins and the MOX fuel pins are arranged in a subassembly aiming at reducing the number of TRU loaded fuel pins. Results are shown with a focus on power distribution in a subassembly.