The high temperature gas-cooled reactor has inherent safety characteristics that permit this class of reactor to comply with the siting requirements of 10 CFR 100 with unique ease, particularly regarding the exclusion area boundary. As a consequence, the size of the reactor site can be selected without regard to 10 CFR 100, and the possibility of locating closer to populated areas is eased. The inherent safety characteristics are the all-ceramic reactor core with pyrocarbon fuel cladding, which can withstand very high temperatures, and the large mass of the core-graphite, which has a great thermal criteria. As a consequence, a slow “time-dependent” release of fission products to the containment would occur in the event of a hypothetical TID-type accident.