A METHOD OF SIMULATING VOIDS IN EXPERIMENTAL STUDIES OF BOILING WATER REACTORS

摘要

The coolant density in boiling water reaotors may vary from < 0.1 to 0.8 gm/cm at pressures up to 1000 p.s.i. In order to study the effect of reduced water density on reactivity in unpressurized experimental systems, the effective water density is reduoed by packing small beads of highly expanded polystyrene into the fuel clusters and flooding the interstioes with water. Coolant densities of from 0.4 to 0.6 gn/om3 may be produced with the introduction of only about 0.4 gm/om3 of non-hydrogeneous material. This memorandum describes the production, properties and handling of polystyrene beads and the tests carried out to establish the validity of the technique.