Material Disposal Areas at LANL

Access

Access Agreements

MDA A

Material Disposal Area (MDA) A

MDA A is a Hazard Category 2 nuclear facility comprised of a 1.25-acre, fenced, and radiologically controlled area situated on the eastern end of DP (Delta Prime) Mesa. DP Mesa is bounded by DP Canyon to the north and Los Alamos Canyon to the south.

MDA A is currently inactive and undergoing corrective action.

MDA A currently contains the following features and was historically used to dispose of wastes generated during operations:

• Two 50,000-gal. cylindrical steel storage tanks (referred to as the General's Tanks and designated structures TA-21-107 [West] and TA-21-108 [East] constructed for underground storage emptied in the 1970's, the tanks contain residual sludge from waste solutions contaminated with plutonium-239/240 and americium-241.
• Two eastern pits containing solid waste potentially contaminated with polonium, plutonium, uranium, thorium, and other unidentified chemicals associated with Laboratory operations.The two eastern pits received waste from 1945 to 1946.
• One central pit containing TA-21 decontamination and decommissioning debris potentially contaminated with radionuclides. The central pit received waste from 1969 to 1978.
• A former surface drum storage area that was used to store drums of sodium hydroxide solution and stable iodine and that reportedly was contaminated with plutonium and possibly uranium. The drum storage area was used from the late 1940s until 1960.
• Two vertical shafts were installed to clarify rinse water generated by cleaning cement paste from a transfer hose between the pug mill and the Genera's Tanks. The General's Tanks were never filled with cement paste and the shafts were never used. The vertical shafts were constructed in 1975 and filled with soil in 1977.

MDA B

Material Disposal Area (MDA) B

Material Disposal Area (MDA) B is an inactive subsurface disposal site, designated as Solid Waste Management Unit (SWMU 21-015), that may contain both hazardous and radiological chemicals. The site is located in Technical Area 21 (TA-21), on Delta Prime (DP) Mesa (a mesa separating Los Alamos Canyon and DP Canyon) MDA B occupies approximately 6 acres and consists of disposal trenches that were used from 1944 until it closed in 1948.  MDA B received process wastes from operations within TA-21 at DP East and DP West. The wastes disposed of at MDA B were highly heterogeneous, primarily radioactively contaminated laboratory wastes and debris, and limited liquid chemical waste; however, a formal waste inventory was not maintained.

The scope of work for MDA B will be to perform a removal, characterization, and restoration (RCR) at SWMU 21-015. RCR activities regarding the hazardous chemical component of MDA B are regulated by the New Mexico Environment Department (NMED) through a Compliance Order on Consent. MDA B also is classified as a hazard category 3 nuclear facility in accordance with U.S. Department of Energy (DOE) Standard 1027-92, Hazard Categorization and Accident Analysis Techniques for Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports, and subject to authorization basis requirements specified in 10Code of Federal Regulations (CFR) 830, Nuclear Safety Rule.

The scope of activities for MDA B will be effective in the long term by removing all contaminant source material, thereby permanently reducing human health and ecological risk and removing the potential for any ongoing releases in the subsurface. MDA B will remain under the control of the federal government until decisions are made concerning the future commercial development of the DP Road corridor.

MDA C

Material Disposal Area (MDA) C

MDA C is a Hazard Category 2 nuclear facility comprised of a 11.8-acre, fenced, and radiologically controlled area situated on a mesa at the head of Ten Site Canyon.The site consists of 7 pits and 108 shafts, with depths ranging from 10 to 25 feet below the original ground surface.

Historically, MDA C was used for the disposal of solids and liquids including uncontaminated classified wastes, hazardous chemicals, and radionuclides.

MDA G

Material Disposal Area (MDA) G

MDA G is a decommissioned (i.e., removed from service) subsurface site for disposition of low-level
waste, certain radioactively contaminated infectious waste, asbestos-contaminated material, and
polychlorinated biphenyls. The site, located on Mesita del Buey, consists of inactive subsurface units that include 32 pits, 194 shafts, and 4 trenches with depths ranging from 10 to 65 feet below the original ground surface.

MDA H

Material Disposal Area (MDA) H Reports

• Periodic Monitoring Report for Vapor-Sampling Activities at Material Disposal Area H, Solid Waste Management Unit 54-004, at Technical Area 54, Fiscal Year 2007

MDA T

Material Disposal Area (MDA) T

The Environmental Programs (EP) Directorate is leading the Laboratory's participation in a national DOE effort to clean up sites and facilities formerly involved in weapons research and development. The EP Directorate's goal is to ensure that past operations do not threaten human or environmental health and safety in and around Los Alamos County. To achieve this goal, the Laboratory is currently investigating sites potentially contaminated by past operations; the sites under investigation are designated as consolidated units, solid waste management units (SWMUs), or areas of concern (AOCs).

Consolidated Unit 21-016(a)-99, also known as Material Disposal Area (MDA) T, is located within Technical Area (TA) 21 at Los Alamos National Laboratory (LANL or the Laboratory). MDA T is categorized as a nuclear hazard category HC 2 facility. As a result of its operational history, Consolidated Unit 21-016(a)-99 (MDA T) contains both radioactive and hazardous components. The site includes four absorption beds that received treated radioactive liquid waste, 64 buried shafts used for the disposal of cement-treated radioactive mixtures, and the Retrievable Waste Storage Area (RWSA) used for the storage of cement-treated radioactive mixtures. The site also includes two industrial wastewater treatment plants and associated subsurface piping and structures. Information on radioactive materials and radionuclides, including the results of sampling and analysis of radioactive constituents, is voluntarily provided to the New Mexico Environment Department (NMED) in accordance with DOE policy.

Operational History of MDA T

The operational history of MDA T is complex, beginning with waste disposal in 1945 and continuing through the backfilling and grading of the site in 1986. Operational discharges of industrial wastewater from the plutonium processing facility to the absorption beds began in 1945. When discharge to the beds reached several thousand gallons per day, the beds became congested and were removed from service in 1950. An industrial waste water treatment plant (Building 21-035) was constructed in 1952 to remove plutonium and other radionuclides from the liquid waste and to improve the absorption characteristics of the wastewater.

MDA U

Material Disposal Area (MDA) U

MDA U consists of four inactive solid waste management units (SWMUs) consolidated into 21-017(a)-99 in 1999 according to their related operational history: SWMUs 21 017(a) and 21-017(b), the absorption beds on the west and east side of MDA U, respectively; SWMU 21-017(c), a former distribution box located between the two absorption beds (removed in 1985); and SWMU 21-022(f), a sump (21-173) that received effluent from Building 21-152 and discharged to the absorption beds through the distribution box. SWMU 21-022(f) was not included as part of the MDA U investigation because it is being addressed as part of the corrective actions being conducted in conjunction with the DP Site Aggregate Area investigation.

In 2005 Field Investigations were conducted to finalize surface and subsurface chemical and geotechnical characterization of MDA U in accordance with the New Mexico Environment Department (NMED)-approved MDA U investigation work plan. Characterization data were used to define the nature and extent of contamination associated with waste disposal activities at MDA U and to determine if the site poses a potentially unacceptable risk to human health or the environment.

Field investigation activities in 2005 included characterization drilling and logging of nine boreholes, continuous core sampling in 5-ft intervals, field screening for radiation and volatile organic compounds, collecting surface and subsurface samples for chemical characterization, and collecting subsurface samples for geotechnical characterization. Based on the characterization data from the 2005 investigation, as well as previous investigations conducted at the site, the nature and extent of contamination in both surface and subsurface media are defined. Additionally, it has been confirmed that no perched saturation zones exist beneath the site.

NMED concurred that the requirements of the March 1, 2005, Consent Order had been satisfied and issued Certificates of Corrective Action Complete with Controls for SWMUs 21-017(a), 21-017(b), and 21-017(c). The first control is that the land use at these sites remains industrial. The second control is the prohibition of construction of any structures at MDA U. LANL plans to request the removal of SWMUs 21-017(a), 21 017(b), and 21-017(c) from its Hazardous Waste Facility Permit in its next request for permit modification.

MDA V

Material Disposal Area (MDA) V

MDA V is categorized as a radiological facility. It consists of three historic wastewater absorption beds that received effluent form the DP Site radioactive laundry facility from 1945 to 1963, two surface debris disposal sites, and a former septic system and outfall from the laundry facility.