Pressure Equalization System for Gas-Cooled Fast Breeder Reactor Fuel Elements

A system has been designed for the gas-cooled fast breeder reactor (GCFR) which equalizes the pressure within the fuel rods with the coolant pressure (85 atm of He) in order to eliminate the possibility of creep collapse of the fuel rods. Additional advantages that result from this design are a shortened core, relaxation of cladding tolerances, low coolant circuit activity, capability of identifying and monitoring leaking fuel elements, safer fuel handling and transport, and potential performance improvements. The system employs in-core charcoal fission-product traps and permits reactor operation with leaking fuel elements. A capsule test of the concept in the ORR has been made and results to date indicate that pressure-equalized fuel is practical and will reduce the development required for the GCFR.