Architecture and management of a geological repository - Andra

4 – Waste disposal PackagesThe second model (Figure 4.3.2) is small in diameter (about 600 mm with a thickness of 120 mm ofsteel)and contains only one assembly. For CU2 type fuel (MOX), the thermal power of such acontainer is about 1100 W, after storage of approximately 90 years once unloaded from the reactor.This second model can also house UOX fuel whose reactivity concerning criticality risks is higherthan that of standard spent fuel (see below).For CU3 type fuel, the disposal package is similar to those developed for C0.3. The number ofcladdings placed in such a container results in thermal power of less than 150 W (identical for C0 typepackages): ten claddings for CU3.1.1 type fuel, five claddings for CU3.1.2 and one cladding forCU3.2 and CU3.3.The large diameter model illustrated by Figure 4.3.1 is equipped with a cast iron insert holding fouremplacements (of square or circular section depending on whether the assembly is clad or not). Thisinsert ensures container mechanical resistance during gradual loading and contributes to criticality riskcontrol by separating the assemblies.Design of small diameter containers is similar to that of C waste overpacks, but with increasedthickness of steel as illustrated by Figure 4.3.2. The steel shell cylindrical cavity makes it possible tohouse the assembly directly (bare or in cladding).Figure 4.3.1Large diameter disposal package, 4 UOX or URE assembliesDOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM146/495