Physics Considerations Involved in the Use of Insoluble Poisons as an Alternate Means of Ensuring Subcriticality in the Rotary Fuel Dissolver

摘要

While the use of soluble neutron poisons coupled with mass control is sufficient to guarantee subcriticality in the rotary fuel dissolver, an alternate means of ensuring subcriticality was also investigated from a reactor physics viewpoint. The scheme proposed in this report relies on the use of 0.25-in. diam stainless-steel-clad B sub 4 C pellets which could be mixed uniformly with the sheared fuel from the Fast Flux Test Facility (FFTF) as it is being fed to the dissolver. The calculations described herein show that an infinite system of the type just described would be safely subcritical (k/sub infinity/ less than or equal to 0.95) at all H/Pu ratios as long as the relative volume of FFTF fuel in the dry system does not exceed 34%. The operational complexities and equipment modifications necessary to employ this method of criticality control have not been examined. 5 references, 6 figures, 8 tables. (ERA citation 09:045507)