A study of transmutation of minor-actinide in a thermal neutron field of the advanced neutron source

Abstract

Since Minor Actinides (MAs) have a large cross section in a thermal energy region, a thermal neutron field has possibility to provide high relative transmutation rate. The transmutation of MA in a thermal neutron field was investigated in this study, focusing on relative transmutation rate, transmutation rate of weight and neutron economy in a thermal neutron field in comparison with those in a fast neutron field. The followings are the major results: (1) a thermal neutron field, especially a well-thermalized neutron field, provides high relative transmutation rate of MA. (2) However, the transmutation rate of weight of MA is limited since the region with high flux is restricted even in the ANS. (3) The accumulation of 246Cm slows the relative transmutation rate of MA in a thermal neutron field. However, it can be compensated by providing a neutron field with high flux in keV region. (4) The neutron economy of the transmutation of MA is not so bad in a thermal neutron field, and is rather good when the neutron flux is high.