Tome Architecture and management of a geological repository - Andra

7 - Spent fuel repository zoneMaterial weights vary according to the type of fuel and type of assembly. They are given Table 7.1.2.Table 7.1.2Mass of PWR fuel assemblies (by material and total mass)Material weight per assembly (in kilograms)Nickel alloy(end piecesprings andgrids)Assembly Ceramic fuel Zirconiumalloy (rodcladding)Stainlesssteel (endpieces, rodsprings, etc.)Total weight ofassembly)(in kilograms)AFA-2GE 521.2 (UO 2 ) 125.6 2.1 16.4 665UOX/UREAFA-2LE UOX 608.1 (UO 2 ) 146.2 2.5 19.5 775AFA-2GE MOX 513.9 ((U-Pu)O 2 ) 125.6 2.1 18.1 660With respect to geological disposal study, one of the common issue to spent fuel and vitrified C wasteis their considerable thermal release linked to their radiological inventory.Nevertheless, the major contribution made by plutonium to fuel thermicity means a longer thermicphase; this difference is with vitrified waste due to the period of the involved isotopes, mainlyamericium-241 ( 241 Am), a daughter product of plutonium-241 ( 241 Pu).Evolution over time in the residual heat rating of the UOX and MOX assemblies, after unloading fromthe reactors, is illustrated in Figure 7.1.2.Figure 7.1.2Puissance thermique (Watt parassemblage)3000280026002400220020001800160014001200100080060040020000 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300Durée de refroidissement (an)Assemblage UOX AFA-2GEAssemblage UOX AFA-2LEAssemblage MOX AFA-2GEEvolution in residual heat rating of UOX and MOX fuel assembliesIn the previous figure, the heat ratings are deducted from the UOX and MOX fuel radiologicalinventories. For the specific UOX AFA-2GE and UOX AFA-2LE assemblies, an envelope inventoryhas been defined for a mixture of UOX2, UOX3 and enriched recycled uranium fuels.Dossier 2005 granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY196/228