A design study on the 1500 MWe class core of metal fuel FBR

A nuclear design study on the 1500 MWe class metal fuel FBR core has been conducted. The target of this study is to clarify if the advantageous characteristics identified for smaller scale cores are maintained in this large output scale. The specifications and design criteria applied in this study are similar to those sets of the 1000 MWe class compact and high burnup core designed by CRIEPI. Preliminary calculations revealed the sodium void reactivity is minimized by flattening the core shape. The resultant core of 100 cm height and 355 cm diameter satisfied all the design criteria. The sodium void reactivity was saturated on a level with 1000 MWe class cores. Based on the evaluation of reactivity feedback characteristics, the feasibility of passive safety potential of 1500 MWe class cores was confirmed. Further, it was showed that this flattened core could be controlled without spatial reactivity swing by normal control systems which consist of 24 primary and 7 secondary control assemblies. From these results, it was found that the advantages of metal fuel core static characteristics may be achievable to 1500 MWe class cores as well as smaller scale ones. (author)