Performance validation of commercially available mobile waste-assay systems: Preliminary report

摘要

Prior to disposal, nuclear waste must be accurately characterized to identify and quantify the radioactive content to reduce the radioactive hazard to the public. Validation of the waste-assay systems' performance is critical for establishing the credibility of the assay results for storage and disposal purposes. Canberra Nuclear has evaluated regulations worldwide and identified standard, modular, neutron- and gamma-waste-assay systems that can be used to characterize a large portion of existing and newly generated transuranic (TRU) and low-level waste. Before making claims or guaranteeing any system's performance for specific waste types, the standardized systems' performance must be evaluated. Canberra and Los Alamos National Laboratory's (LANL) Plutonium Facility developed a three-phase validation plan. During Phase One, tests were performed using simulation sources at Canberra to determine the error bounds for measurement parameters, to determine the minimum detectable activity, and to measure precision and bias. During Phase Two, two mobile systems were installed at the Plutonium Facility. LANL is providing peer review of the systems' performance for plutonium, acting as a beta test site to evaluate the waste-assay software, and providing data for (open quotes)precertification(close quotes) at future Department of Energy installations. (Plutonium isotopics are determined from measurements using the Multi-Group Analysis code.) Finally, the two systems' performances are evaluated for representative waste types (salt, metal, combustibles, leaded rubber, and HEPA filters). Phase Three of the validation, the Waste Isolation Pilot Plant Performance Demonstration Plan, will require approval by the National TRU Program Office. This paper describes the standard mobile waste-assay systems, the test plan, and preliminary results from the peer review outlined above in Phase Two.