Experimental and computational study of the pyrocarbon and silicon carbide barriers of HTGR fuel particle

HTGR safety is secured by a system of barriers limiting the emission of fission products from the core into the surrounding environment during normal operation and postulated anticipated accidents. An experimental-computational analysis of two fundamentally important barriers — fuel kernels and their coating, whose function is to contain radionuclides and to protect workers and the environment, is examined. The function of the barriers and the requirements which they must satisfy are examined for HTGR fuel particles. The results of post-reactor studies are analyzed. Mathematical models and computational codes simulating the behavior of fuel particles are analyzed. Probabilistic-statistical models and the GOLT code are being developed to evaluate the behavior of fuel particles under irradiation. Together with other models, this code is used for comparative test calculations of the behavior of particle fuel under normal irradiation conditions (<1300°C). The first results of such calculations are discussed. __________ Translated from Atomnaya énergiya, Vol. 105, No. 1, pp. 14–25, July, 2008.