Transition Core Properties during Conversion of the NBSR from HEU to LEU Fuel

Hanson A. L. ; Diamond D.

关键词: High Energy Uranium (HEU);    Low energy Uranium (LEU);    NBSR;    fuel management;   

DOI  :  10.2172/1121204
RP-ID  :  BNL--102419-2013-IR
PID  :  OSTI ID: 1121204
Others  :  Other: NN9002000

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

The transition of the NBSR from HEU to LEU fuel is challenging due to reactivity constraints and the need to maintain an uninterrupted science program, the mission of the NBSR. The transition cannot occur with a full change of HEU to LEU fuel elements since the excess reactivity would be large enough that the NBSR would violate the technical specification for shutdown margin. Manufacturing LEU fuel elements to represent irradiated fuel elements would be cost prohibitive since 26 one-of-a-kind fuel elements would need to be manufactured. For this report a gradual transition from the present HEU fuel to the proposed LEU fuel was studied. The gradual change approach would follow the present fuel management scheme and replace four HEU fuel elements with four LEU fuel elements each cycle. This manuscript reports the results of a series of calculations to predict the neutronic characteristics and how the neutronics will change during the transition from HEU to LEU in the NBSR.