Design Study on a Large FBR Plant Enhancing Passive Safety.

A conceptual design study on a 1, 300MWe class FBR of loop type using sodium bonded mixed nitride fuel was performed from the viewpoint of the enhancement of passive safety. Spectrum-Adjusted Core concept that shifted neutron spectrum to low energy side by adding zirconium hydride was adopted to enlarge the negative Doppler reactivity feedback for the purpose of passive shutdown at ULOF. Integrity of plant system at transients was also examined under long flow coast down condition. It has been found that the large FBR concept with enhanced passive safety characteristics has sufficient feasibility for commercialization and the increase of the capital cost concerning passive safety is not a burden.