Nuclear reactor core passive protection system - esp for fast neutron reactor based on fall under gravity of fuel melted by local overheating

摘要

At the bottom of each of a number of separate safety rods which are substituted in the core for normal fuel rods, is a crucible section of refractory material above which is an expansion chamber for fission product gasses with at its top a ring diaphragm supporting a plug, with small central bore, of refractory material. This in turn suports a refractory hollow cylinder with relatively large bore on which in turn are stacked hollow cylindrical pellets of fuel material lining the sheath of the element. Fuel melted by local overheating due to excess neutron flux flows down into the refractory sections reducing reactivity thereby in the overheated mid-section.