1. Evaluation of the radiological consequences of tritium present in radioactive components from fusion reactors Task TW4-TSW-001-D1b: Waste and decommissioning strategy: waste disposal criteria Dirk Mallants

2.  Current practice in fusion waste management studies: use of acceptance criteria (WAC) derived from Fission waste  Objective: Evaluate if WAC appropriate for fusion waste  Develop approach for deriving fusion-specific WAC  Based on Safety Assessment Modelling (leaching)  Methodology developed for LILW (fission), applied here for SEAFP-2 plant model (representative for PPCS plant model A)  Disposal concept: multi-barrier surface repository  Inventory: tritium after 100 y cooling (5.6  10 17 Bq), mainly in LiPb (breeder: 5.5  10 17 Bq) (e.g., no compliance with El Cabril WAC)  Release mechanism: diffusion in solids & porous media (concrete engineered barriers) Objectives & Methodology

3. Results 2D tritium profiles in repository Annual total dose for groundwater pathway

4. Conclusions If post-closure institutional control is in place:  Zero release (no radiological impact on groundwater)  Institutional control is required for at least 100 y to monitor tritium release If post-closure institutional control is ineffective:  Radiological impact << dose limit for public (1 mSv/y) if repository filling is optimized (waste is acceptable)  If filling is not optimized: Radiological impact  dose limit Other (long-lived) radionuclides need to be included in safety assessment Need to develop fusion specific acceptance criteria accounting for fusion-specific waste characteristics Optimization of disposal design and practices to accommodate fusion waste in surface repositories