LANL Cleanup Work At TA-21 Delayed Due To Higher Level Of Contamination Determined On Site

The Los Alamos Reporter and former Department of Energy Environmental Management Los Alamos Field Office Manager Doug Hintze exit Building 257 in TA-21 in August 2019. Courtesy photo

Building 257 at Technical Area 21 in August 2019 during a tour by the Los Alamos Reporter. Courtesy photo


When the Los Alamos Reporter visited Technical Area (TA) 21 at the end of DP Road in Los Alamos in August 2019 with former Department of Energy Environmental Management Los Alamos Field Office manager Doug Hintze, Building 257 was part of the tour.

More than a year beforehand, N3B, the legacy waste cleanup contractor for Los Alamos National Laboratory had taken over the remaining cleanup of TA-21 from DOE and begun working on Building 257, a former radioactive liquid waste processing facility. TA-21 is a former Manhattan Project and Cold War era complex where plutonium was processed and tritium research for energy, environment and weapons defense was conducted. Most of the buildings at TA-21 were demolished in 2011 and the plan was to decontaminate and demolish Building 257 and remove underground waste transfer lines.

Last winter, higher levels of contamination than expected were found in Building 257 and in the waste lines. The previous nuclear safety characterization was “less than Hazard Categorization 3”, which meant that the contamination was expected to be low-level. Building 257 and the waste lines had been considered “cold and dark” since 1993. It appears that no sampling was conducted prior to turning the cleanup over to N3B.

Data collected from both non-destructive assay and analytical chemistry methods indicated a higher radionuclide inventory existing concluded that there were at Hazard Categorization 3 level.

N3B declared concern earlier this year about the safety analysis for the project and since then all work planned for FY21 has been postponed. Before work resumes, an “unreviewed safety question” has to be addressed and additional controls and protective measures will be required.

Cleanup of TA-21 was supposed to have been completed in 2022. Two Material Disposal Areas in TA-21, MDA A and MDA T are supposed to be cleaned up by 2028-2031.

DOE materials state that MDA A, which was used from 1945-1947 and from 1969 to 1975, is an inactive 1.25-acre subsurface site for the disposal of solid and liquid radioactive wastes. Portions are managed as a nuclear facility due to the types and amounts of buried radionuclides. Combustible and non- combustible radioactive solid wastes were disposed in the central pit and in the two eastern trenches. There is very little documentation detailing the types of chemicals and quantities of radionuclides in the pit and trenches. Radioactive liquid wastes were stored in two 50,000-gallon underground tanks (dubbed the General’s Tanks). From 1975-1981, much of the liquid portion of the waste was pumped from the tanks, leaving residual liquid and sludge at the bottom of each tank.

MDA-T is located immediately west of MDA A. It is a 2.2-acre radiological waste disposal site consisting of four plutonium-contaminated absorption beds used to dispose of liquid wastes from 1945-1952; a retrievable waste storage area; a series of cylindrical disposal shafts 2-3 feet in diameter and up to 60 feet deep, containing cement mixed with radioactive elements; an acid holding tank and acid sump;  a caisson built in 1959 at the northwest corner of absorption bed;  an inactive container storage area for alcohol, acetone, and freon; and two surface spills of radioactive waste.

The Northern New Mexico Citizens Advisory Board has asked DOE for a presentation on Building 257 at their next meeting. There will likely be questions about the additional funds necessary to complete the cleanup due to the new categorization of the waste. Removal and remediation of buried waste lines and contaminated soils are part of the DP Aggregate Area investigation, whereas demolition of the DP West slabs and Building 257 are not part of the 2016 Consent and will be executed under DOE requirements.