Architecture and management of a geological repository - Andra

4 – Waste disposal Packages4.3.3.1 DescriptionTwo categories of disposal packages, having standardised dimensions, cover all spent fuel of CU1 andCU2 types presented in section 3.• Large diameter disposal package (4 assemblies)This package with a standard diameter of 1255 mm and length varying between 4500 and 5400 mmand weight between 35 and 43 metric tons according to configuration (short or long assembly 50 , bareor clad assemblies) is composed of two main parts: a body equipped with an insert and a lid as well asan intermediate component known as the closure plug.Container bodyThe disposal package body of large diameter is composed of a cylindrical shell in non-alloy steel(P235) of rated thickness of 110 mm and a bottom of the same rated thickness and material to fulfilleaktightness requirements during 10,000 years. A thickness of 20 mm is added to the rated thicknessof the bottom to act as a root face for electron beam welding.In the body (see § 4.3.4 below), a cast iron insert is poured equipped with four emplacements eachdesigned to receive one fuel assembly.Insert emplacements illustrated by Figure 4.3.3 and Figure 4.3.4 have geometry adapted to thecomponents to be inserted, so as to limit residual voids in the disposal package:- bare assemblies are placed in emplacements of square section;- assemblies in individual cladding are placed in emplacements of cylindrical section.Figure 4.3.3 Square emplacements for fourbare spent fuel assembliesFigure 4.3.4 Cylindrical emplacements forfour spent fuel assemblies in individualcladdingMinimum thickness of the insert between the emplacements and the shell is defined taking intoaccount the limits of the manufacturing process applied (foundry). It is evaluated at about 40 mm. Thisvalue has been adopted for both variants (square emplacements and circular emplacements) and issufficient to ensure mechanical resistance of the insert when loaded (see below).This minimum thickness is also applied to the distance between emplacements.50Short assemblies have come from EDF 900 Mwe reactors and long assemblies from EDF 1300/1450 MWe reactors (cf. § 3.2.3.1)DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM148/495