1 Material Disposal Areas David S. Rhodes Acquisition Integrated Project Team Chair Environmental Management Los Alamos Field Office March 3, 2015

2 Material Disposal Areas  MDA-A at TA-21 Complete a removal action of two 50,000 gallon plutonium solution (General’s) Tanks with sludge heels o The removal action could be relatively near-term (3-4 years) Complete investigation and evaluate alternatives of central debris pit and waste trenches, support NMED development of a Statement of Basis for a remedy Execute the remedy which is planned as (but not determined) an engineered cover including material procurement and construction  MDA-C Support NMED development of a Statement of Basis for a remedy Execute the remedy which is planned as (but not determined) an engineered cover including material procurement and construction o This might be appropriate for a near-term capital asset project  MDAs-G, -H, and L at TA-54 Support NMED development of a Statement of Basis for each of three potential remedies Execute the remedy which are planned as (but not determined) engineered covers including material procurement and construction and possibly includes Soil-Vapor Extraction (SVE) for Areas L and G Highly dependent on Transuranic (TRU) Waste completion schedules

3 Material Disposal Areas  MDA-T at TA-21 Complete investigation and evaluate alternatives of central debris pit and waste trenches, support NMED development of a Statement of Basis for a remedy Execute the remedy which is planned as (but not determined) an engineered cover including material procurement and construction Expected to remain under Federal control indefinitely  MDA-AB at TA-49 Complete investigation and evaluate alternatives of central debris pit and waste trenches, support NMED development of a Statement of Basis for a remedy Execute the remedy which is planned as (but not determined to be) an engineered cover including material procurement and construction

4 MDA-B History  Waste disposal site consisting of a series of shallow disposal trenches for hazardous and radioactive wastes Approximately 6 acre site operated from  2010 CD-2 baseline $110.5M Total Project Cost Completion September 30, 2012 Estimated at 22,000 cubic yards Thought to be shovel-ready for American Recovery and Reinvestment Act (ARRA) project – minimally characterized  Actual completion performance $131.2M total project costs Completed March 31, ,000 cubic yards from trench depths twice what expected

5 MDA-A at TA-21  Two buried General’s Tanks 50,000 gallon plutonium solution recovery No known releases from tanks Coffer dams installed for access Sampled and Light Detection And Ranging (LIDAR) surveyed heels Expected to be TRU waste  Central construction debris pit Potentially radiologically contaminated  Two disposal trenches Operated same timeframe as MDA-B trenches Expect similar disposal practices (end of trenches with more content)

6 MDA-A Aerial View

7 MDA-A  Remedy expected to be driven by radiological contaminants DOE likely regulatory decision-making authority Some hazardous constituents expected with NMED regulatory authority Still missing information for evaluating alternatives  Requested NMED allow completion of characterization NMED decision on characterization pending  Next steps DOE-directed General’s Tanks Removal Action Phase II investigation work plan and field sampling activities for pit and trenches Phase II Investigation Report Corrective measures evaluation to considered excavation of engineered cover NMED Statement of Basis Remedy implementation

8 MDA-C  Site background and operational history 11 acre site Borders NNSA operational facilities Fenced and graded with stabilizing cover plants  Vadose zone VOC plume Pore gas monitoring Impacts on adjacent new projects for construction worker scenario  LANL recommended alternative SVE Evapo-transpiritive (ET) cap with bio-intrusion barrier and native vegetation Long-term monitoring and maintenance  NMED review of Corrective Measures Evaluation and Draft Statement of Basis pending

9 MDA-C layout

10 MDA-C vapor plume

11 MDA-L remedy project  Site background and operational history 2.5 acre TA-54 site, located adjacent to Pueblo de San Ildefonso Used from 1959 to 1985 Subsurface pit / impoundments / shafts used for disposal of chemical wastes  CME overview CME revised and submitted to NMED September 2011 CME addresses hazardous constituents in units, and VOC vapors in vadose zone Alternatives considered – no action, and combinations of capping, excavation and SVE  LANL recommended alternative SVE Evapo-transpiritive (ET) cap with bio-intrusion barrier and native vegetation Long-term monitoring and maintenance  NMED review of Corrective Measures Evaluation and Draft Statement of Basis pending

12 MDA-L Facilities

13 MDA-H remedy project  Site background and operational history 0.3 acre TA-54 site, located adjacent to Pueblo de San Ildefonso Used from 1960 to 1986 Subsurface shafts used for disposal of classified solid wastes  CME overview CME revised and submitted to NMED September 2011 CME addresses hazardous constituents in units Alternatives considered – no action and combinations of capping and excavation  LANL recommended alternative Evapo-transpiritive (ET) cap with bio-intrusion barrier and native vegetation Long-term monitoring and maintenance  NMED review of Corrective Measures Evaluation and Draft Statement of Basis pending

14 MDA-G remedy project  Site background and operational history Within 63-acre TA-54 site, located adjacent to Pueblo de San Ildefonso Used since 1957, intermingled with active Area G LLW disposal units Subsurface pit / shafts / trenches used for storage and disposal of solid and radioactive wastes  CME overview CME revised and submitted to NMED September 2011 CME addresses hazardous constituents in units, and VOC vapors in vadose zone Alternatives considered – no action, and combinations of capping, excavation and SVE DOE radiological regulatory authority will be integrated with NMED selected remedy  LANL recommended alternative Evapo-transpiritive (ET) cap with bio-intrusion barrier and native vegetation Targeted SVE Long-term monitoring and maintenance  NMED review of Corrective Measures Evaluation and Draft Statement of Basis pending

15 MDA-G Aerial View of Facilities

16 MDA-T Overview  Site background and operational history Approximately 2 acres site Four absorption beds operated from 1945 to 1967 Waste disposal shafts used from 1968 to 1975 for TRU waste disposal and after 1975 for only LLW  Four Absorption Beds 16 million gallons treated and untreated plutonium wastewater from DP West (mostly floor drains and decontamination water) 2 million gallons untreated tritium wastewater from DP East Estimated to contain approx. 9.8 curies plutonium  Waste Disposal Shafts Located between absorption beds ~64 shafts 2-, 6- and 8-ft diameters, 15 to 69 ft. deep, some with asphalt lining Covered with 2 – 5 ft. of concrete and 4 – 6 ft. of crushed tuff Mostly radioactive liquid waste mixed with Portland cement from pugmill, some shafts used for rinse water only Some waste debris including 21 bathyspheres in 5 shafts and 8 55-gallon drums in 2 shafts Estimated to contain 4,000 to 12,000 curies, americium, plutonium, uranium, and mixed fission products

17 MDA-T Overview  Current Investigation results Elevated Pu 239, 240 above residential and industrial screening action levels (SAL) below the absorption beds o Concentrated below absorption beds and building footprint o Depth is approximately 40’ below the ground surface VOCs, semi-volatile organic chemicals (SVOC) and other metals are near background or industrial soil screening levels (SSL), as appropriate Phase 2 screening showed pore gas is not a threat to the groundwater No samples directly from absorption beds but one sample from the shafts

18 MDA-T Overview  Remaining Work Vadose Zone Moisture Monitoring Work Plan but not conducted o Test pit, 4 angled boreholes, 1 or 2 deep vertical boreholes o One deep vapor well near Corrective Measures Evaluation (CME) o CME provides remedy alternatives analysis and a preferred remedy  Range of alternatives include capping ($105M) to full excavation ($1.2B) o NMED selects final remedy and issues a Statement of Basis o NMED’s selection must undergo public comment period Wells R-64 and R-65 Integrated approach for MDAs A&T (possible) Performance Assessment and Composite Analysis (PA/CA) o DOE regulates radiological hazards and integrates with NMED

19 MDA-T at TA-21 Views  Phase I Investigation Report completed in September 2006  Need CME  Expected engineering cover as remedy

20 MDA-AB at TA-49  Operated from January 1960 – August Underground hydro-nuclear experiments evaluated the possibility of starting a nuclear reaction from accidental high explosive detonation  The Nuclear Environmental Site (NES), a Hazard Category 2 Nuclear Facility Areas 1, 2 (Material Disposal Area AB [MDA AB]), and 4 include a subset of 82 shafts, approximately 3 acres. Depths ranged from 31 feet – 108 feet below ground surface and Ranged from 3 feet – 6 feet in diameter Area 3- Contains 13 shafts. No radiological materials used Area 11- Radiochemistry Laboratory and Small Scale Experiments Area 12- Bottle House and Cable Pull Test Facility  Areas Outside the NES Areas 5, 6 and 10

21  REMAINING IN THE 82 SHAFTS Plutonium = 88 lbs. (40 kg) Uranium-235 = 205 lbs. (93 kg) Uranium 238 = 375 lbs. (170 kg) Beryllium = 24 lbs. (11 kg) Lead = 99 tons – shots were encased in lead  CONSUMED High explosives: TNT, HMX (high melting explosive), and RDX (research department explosive) MDA-AB at TA-49

22 MDA-AB at TA-49 Overhead Investigation Area Outside NES Investigation Area Inside NES