Progress in the studies of the Advanced Plutonium fuel Assembly

A new assembly concept, designated APA (for (A) under bar dvanced (P) under bar lutonium fuel (A) under bar ssembly), should make it possible to multi -recycle plutonium in pressurized water reactors. The basic idea is founded on the manufacture of a large plutonium thin annular fuel rod with an iner t support, cooled on both faces. The absence of plutonium generation, combi ned with moderate fuel temperature should make it possible to achieve subst antial burn-up fractions in these rods. The assembly is compatible with the internals of a Pressurized Water Reactor (PWR), and provides for permanent reversibility. Neutronic studies showed a compliance with actual safety/co ntrol criteria. A multi-recycling scenario was simulated for 84 years' oper ation with a 65 GW electrical power installed capacity, comprising forty-fi ve 1450 MW electrical power PWRs, 32 of which are loaded with UO2 and 13 wi th APAs. It showed that the plutonium inventory is controlled. Thermal-hydr aulic studies showed one can find an annular rod geometry allowing one to r espect both margins to Critical Heat Flux (CHF) during normal and accidenta l operations and void fraction limitations (C) 2001 Published by Elsevier S cience Ltd. All rights reserved.