Vitrification and encapsulation modules for back-end simulation in ANICCA

In nuclear fuel cycle simulations, the back-end is often represented through cumulative spent fuel or high-level waste (HLW) inventories, while conditioning and packaging steps are simplified or omitted. This is especially limiting for advanced recycling strategies, including minor actinide (MA) transmutation, which are commonly assessed through radiotoxicity and decay heat but not through the amount of conditioned waste or final disposal canisters. This work addresses this gap by extending the ANICCA fuel cycle code with two back-end facilities: Vitrification and Encapsulation. The Vitrification module converts residual HLW into discrete glass logs under constraints on decay heat, cumulative alpha dose, plutonium content, and waste loading. The Encapsulation module converts vitrified HLW or non-reprocessed spent fuel into final disposal canisters, subject to geometric and decay-heat limits at emplacement.The framework is applied to three strategies under a common electricity generation basis: an open UOX cycle, a closed cycle with Pu recycling, and a closed cycle with Pu and MA transmutation in lead fast reactors. Using as-needed reprocessing, Pu recycling reduces final canisters and estimated disposal length by 49.16% and 47.45% relative to the open cycle, while Pu+MA recycling reduces them by 57.07% and 54.14%. Compared with Pu-only recycling, Pu+MA gives a further reduction of 15.56% in canisters and 12.72% in disposal length.The results show that HLW mass and glass log counts alone do not fully characterize back-end performance. The main gain of Pu+MA appears at encapsulation, where higher loading reduces HLW canisters by 21.69%, partly offset by residual LFR spent fuel.