A Methodology for Accident Analysis of Fusion Breeder Blankets and Its Application to Helium-Cooled Lead–Lithium Blanket

“Fusion for Energy” (F4E) is designing, developing, and implementing the European helium-cooled lead-lithium (HCLL) and helium-cooled pebble-bed test blanket systems (TBSs) for ITER (Nuclear Facility INB-174). Safety demonstration is an essential element for the integration of these TBSs into ITER and accident analysis is one of its critical components. A systematic approach to accident analysis has been developed under the F4E contract on TBS safety analyses. F4E technical requirements, together with Amec Foster Wheeler and Idaho National Laboratory efforts, have resulted in a comprehensive methodology for fusion breeding blanket accident analysis that addresses the specificity of the breeding blanket designs, materials, and phenomena while remaining consistent with the approach already applied to the ITER accident analyses. The methodology phases are illustrated in this paper by its application to the EU HCLL TBS using both MELCOR and RELAP5 codes.