THE ZPPR-4 DEMO CRITICALS PROGRAM*

The ZPPR-4 critical assembly was designed to be similar to the Clinch River Breeder Reactor Plant (CRBRP) design in overall shape, configuration and region-average compositions. A four phase program, directed at design input to the CRBRP, blanket performance, blanket fissile buildup effects, full-core breeding performance and plutonium isotopic effects is described. Experimental results for reaction rate distributions in the blanket, control rod and rod group worths and plutonium isotopic effects are discussed.