“…15 The radionuclide I-129 is a U-235 fission product with a long half life of 1.6 × 10 7 years. Previously it has only been measured successfully in the Sludge Batch 4 and 5 (SB4, SB5) Waste Acceptance Product Specifications (WAPS) studies 9,11 and SB5 Acceptance Evaluation 16 , where its concentration was reported. Other reported concentrations for previous sludge batches are based on the Waste Characterization System at SRS.…”