IODINE-ASSISTED MASS TRANSFER IN A SIMULATED LMFBR FUEL PIN.

During the operation of liquid metal fast breeder reactor (LMFBR), the fuel reacts with its cladding of stainless steel, which is called fuel-cladding chemical interaction (FCCI). The cladding component chemical transport (CCCT) is one of the important modes of this FCCI. The role of the free iodine produced by radiolysis of CsI vapor in the CCCT has been examined by out-of-pile simulation experiments. The chemical vapor transports of the components of stainless steel and pure iron were tested in the electron-bombarded CsI vapor by using an electron probe microanalyser. Significant amounts of specimen components were transported via vapor phase, while the addition of excess cesium vapor diminished the transport rate.