Possibility assessment for production of non-traditional nuclear fuel in thorium blanket of hybrid thermonuclear reactor

The paper aims at studying specific peculiarities in isotope composition of thorium blanket under irradiation by fusion neutron source (FNS) in hybrid thermonuclear reactor (HTR). High-energy (14 MeV) component of neutron spectrum in thorium HTR blanket results in production of non-traditional fissile mixture including not only233U, but also231Pa232U and 234U. Extraction of such non-traditional fuel from spent Th-blanket and its utilization in traditional nuclear power reactors could increase fuel burn-up and strengthen regime of nuclear non-proliferation. The detailed investigations of these positive effects require high-precision neutron-physical analyses of thorium HTR blanket. The results obtained in these investigations are presented in the paper. The following results were obtained: the chosen model of HTR allowed us to form high-energy neutron spectrum in Th-blanket with significant fraction of 14 MeV neutrons; it was evaluated that threshold (n,2n) and (n,3n)-reactions are able to produce significant amounts of non-traditional target isotopes231Pa and232U; it was shown that accumulation of non-traditional target isotopes weakened substantially in depth of Th-blanket. So, it seems reasonable to seek for optimal thickness of Th-blanket and, thus, to find optimal loading of natural thorium.