Calculational and experimental studies of double heterogeneity of fuel elements in the HTGR reactor

Studies of neutron fields in spherical fuel elements of the HTGR type reactor core consisting of fuel kern in the form of fuel microparticles dispersed in graphite matrix and graphite can are described. The fuel arrangement causes specitic neutron-physical characteristics of fuel elements and approaches to the determination of these characteristics. Complex studies have comprised experiments in the GROG benchmark, precise calculations by the MCU program, calculations of equivalent cell according to the SCOCRT (probabilities of the first collision) program. The experimental data have permitted to test precise calculations and the SCOCRT program providing engineering calculations was tested by them. 7 refs.; 6 figs.; 3 tabs