Summary

This monograph describes a method for taking advantage of the inherent characteristics of sodium cooled reactors to achieve major reductions of the plant capital cost making the LMFBR highly competitive with existing designed LWRs. First, it is proposed to adopt a reactor core design that capitalizes on the breeding principle so as to allow continuous full power operation without refueling for periods of up to ten years. Doing so enables the adoption of a much lower cost (but slower) refueling system, a shortened reactor vessel, and simplifies the containment system. Second, the cylindrical containment is abandoned in favor of a rectilinear containment with no requirement for a single elevation basemat so that space utilization is improved. A related measure is to replace the operating floor concept common to LMFBRs designed to date with a refueling cell that connects the reactor and the adjacent fuel storage. This reduces containment volume and the need for much of the reactor vessel head shielding. Third, the elimination of the elevated loop primary system piping concept similarly reduces containment volume. Fourth, a major reduction in core pressure drop enables the elimination of hydraulic hold-down of core assemblies, probably eliminates the need to consider control rod ejection accidents in the design basis, and facilitates adoption of more compact and trouble free EM pumps for both the primary and intermediate circuits. Fifth, the adoption of naturally circulating Decay Heat Removal Systems permits reduction of the number of primary loops to two, eliminates the requirement for the Intermediate Heat Transport System and Steam Generating System to be safety related, and reduces 1E loads dramatically, likely eliminating the requirement for emergency diesel generators. Finally, auxiliary systems are carefully reviewed for unnecessary features that have a tendency to creep undetected into plant designs.