Potentialities of high-temperature mass spectrometry for studies on the improvement of fission product retention in the nuclear fuel of high temperature gas-cooled reactors

The properties of coated fuel particles are discussed, and the fission product transport from the kernel of irradiated fuels through the coatings to the coolant is considered. In particular the behaviour of fission products in the fuel kernels is examined. It is suggested that useful information about the chemical activity of the fission products, and of various of their compounds or solid solutions, could be obtained by using a Knudsen cell - mass spectrometer system. It is further suggested that the system could be used to obtain information about the penetration of the pyrocarbon, the matrix graphite and the graphite of the fuel-free zone, and finally the evaporation from the surface of the fuel element into the coolant. (U.K.)