Using the HERCULES System to Segregate Room Trash From the LANL Plutonium Facility and CMR Building

The Los Alamos National Laboratory (LANL) Plutonium Facility (PF-4) and the Chemistry and Metallurgy Research (CMR) building are radiological facilities operated by the Nuclear Materials Technology (NMT) Division. Combined, these facilities generate approximately 262 m³ of low-level waste (LLW) per year of routine room trash from laboratories in radiological controlled areas (RCAs). It has been estimated that 50 to 90% of this low-density room trash is free of radioactive contamination and eligible for inclusion in LANL’s Green is Clean (GIC) program. GIC waste includes all non-regulated waste from RCAs that has been actively segregated as nonradioactive through the use of the waste generator’s acceptable knowledge (AK). The High Efficiency Radiation Counter for Ultimate Low Emission Sensitivity (HERCULES) system is one of several nondestructive assay (NDA) measurement systems used in the GIC program to verify the generator’s AK. This highly sensitive system is optimized to detect very small quantities of common LANL radionuclides, especially isotopes of plutonium, americium, and uranium. A pilot project was conducted in collaboration with NMT Division waste management personnel to determine which RCAs generate the greatest volumes of potential low-density GIC wastes. The HERCULES system was used to screen a portion of the low-density laboratory room trash that NMT shipped to LANL’s low-level waste disposal facility in a six-month period from October, 2002–March, 2003. This consisted of 1350 plastic lined cardboard boxes (0.305m × 0.305m × 0.610m) containing between 2.0–13.5 kg each of room trash. Results of the HERCULES screening indicate that with no active segregation attempts by the generator, 33% of the low-level waste boxes are free of radioactive contamination. An additional 42% of the boxes exhibited very low total activities and could probably become legitimate GIC wastes with active segregation employed during the waste generation process. Thus, the expansion of the GIC program to include low-density laboratory room trash could significantly reduce the total volume of LLW generated by NMT Division.