Introduction 1. Quick-Look Identification System 3. Hanford Environmental Restoration Disposal Facility 5. Idaho CERCLA Disposal Facility 7

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2 Introduction The US Department of Energy (DOE) owns and operates a collection of on-site land disposal facilities used to permanently store solid wastes generated from decommissioning of infrastructure associated with historical activities in the weapons complex. s stored in these facilities typically include contaminated soils and building debris containing radionuclides or other constituents traditionally requiring waste containment in an engineered disposal facility. These wastes are normally referred to as low-level radioactive wastes (LLRW), hazardous wastes (HW), mixed wastes (MW), or toxic substances control act wastes (TSCA). DOE Order requires that all on-site disposal facilities be designed and operated to ensure that radiation exposure to the public is acceptable for at least 1000 years following closure of the facility. The planning, radiation protection activities, and future use commitments associated with these facilities are also required to minimize the likelihood that current LLRW disposal activities will result in the need for future corrective actions. This document was prepared to provide DOE management and other interested parties with the current status of the on-site disposal facilities in the DOE complex. Current and future issues are described in a quick-look format that permits a rapid assessment of existing conditions, future risks, and issues in need of both short-term and long-term attention. The document was created based on information provided by DOE project managers and site visits conducted by an independent technical review committee. 1

3 Table of Contents Introduction 1 Quick-Look Identification System 3 Hanford Environmental Restoration Disposal Facility 5 Idaho CERCLA Disposal Facility 7 Oak Ridge Environmental Management Management Facility 9 Portsmouth On-Site Disposal Facility 11 Nevada Test Site Area 5 13 Paducah On-Site Disposal Facility 15 Savannah River Site E Area 17 References 19 Acknowledgement 20 2

4 Quick-Look Identification System This document has been prepared to provide a rapid assessment of existing and future conditions. Information for each site is contained in a quick-look table. Rows in the table are associated with elements or operations that may affect the long-term performance of the facility. The columns represent the current status in the facility timeline (design, operating, closed), the status of monitoring and regulatory compliance, and the prognosis for meeting lifetime performance goals. Current status along the facility timeline is indicated by the following: No design has been proposed. Conceptual design proposed, but not yet approved by public and regulators. Design has been completed; approved by public and regulators. Operating or in use. Completed or closed. At risk elements of design and/or operation may affect progress along timeline. 3

5 of monitoring systems and regulatory compliance is indicated by the following: not yet required. issues have been raised, and may be in resolution. implemented and facility in compliance. Recent compliance problems or future compliance problems perceived. Prognosis for meeting lifetime performance goals is described by: Too little information to evaluate at this time (project under development). All systems, operations, and elements adequate to meet lifetime performance goals. Some systems, operations, or elements may affect lifetime performance goals. At least one system, operation, or element probably will prevent lifetime performance goals. Comments are provided in each row to briefly elaborate on any issues that may impact the timeline, adversely affect regulatory compliance, and/or preclude meeting lifetime performance goals. 4

6 Hanford Site: Environmental Restoration Disposal Facility (ERDF) Facility Overview Liner Design Cover Design (Conceptual) Facility Profile: Commenced Operations: 1996 (currently filling) Operating Contractor: S.M. Stoller Corporation Regulatory Authority: CERCLA s: Contaminated soils, reactors, D&D waste, mixed wastes, hazardous wastes Disposal Rate and Capacity: 1540 tons/d; 16,800,000 tons % Complete 5

7 Landfill Systems Matrix Hanford s ERDF Element Timeline Future Prognosis Comments Liner Collection System Site employs double liner with lower composite barrier consisting of geomembrane over bentonite-amended soil. Geomembrane contribution is ignored in PA, making analysis very conservative. Performance record for composite liners is excellent. Past incident where leachate levels were elevated due to monitoring and operations failure. New automated has been system installed and has remedied this problem. Treatment There are no known problems and no known incidents with the leachate treatment system. Cover Cover has not yet been constructed and therefore monitoring is not yet required. Cover design has not been selected, but current landfilling operation may affect long-term performance of the cover, and regulatory acceptance. Volume Control Soil- Ratio Site has plenty of available land and expansion is possible if needed. Soil-waste ratio has been a contentious issue with regulators. Field testing conducted in to resolve this issue. Report from field testing is being completed. If accepted by regulatory agency, compliance issues will be resolved. Compaction method has been a contentious issue with regulators. Field testing was conducted in to resolve this issue. Report from field testing is being completed. If accepted by regulatory agency, compliance issues will be resolved. Previous compaction monitoring method led to past problems with data falsification. Performance-based method is being tested and implemented. If accepted by regulatory agency, compliance issues will be resolved. settlement and cover support has been a concern of the regulators. Field testing was conducted in to quantify settlement. Settlement projections need to be put in context of cover design (which has not been selected) to ensure performance goals will be satisfied. Compaction Method Compaction Stability & Settlement Environmental Performance There are no known problems and no known incidents with monitoring systems outside the landfill envelope. 6

8 Idaho National Laboratory: Idaho CERCLA Disposal Facility (ICDF) Facility Overview Liner Design Facility Profile: Commenced Operations: 2003 (currently filling) Anticipated Closure Date: Not determined Operating Contractor: S.M. Stoller Corporation Regulatory Authority: CERCLA s: Contaminated soils, D&D waste, evaporation pond residuals, mixed waste, hazardous waste Disposal Rate and Capacity: 250 tons/d; 820,000 tons Cover Design (Conceptual) % Complete 7

9 Landfill Systems Matrix Idaho s ICDF Element Timeline Future Prognosis Comments Liner Collection System Site employs double composite barrier consisting of geomembrane over GCL (upper) or bentonite-amended soil (lower). Geomembrane contribution is ignored in PA, making analysis very conservative. Performance record for composite liners is excellent. There are no known problems and no known incidents with the leachate collection system. Treatment There are no known problems and no known incidents with the leachate treatment system. Cover Cover not yet constructed and therefore monitoring not yet required. Cover design has not been selected even though landfill operations may affect long-term cover performance and regulatory acceptance. Linkage between cover performance and waste settlement ill-defined. Volume Control Need for expansion beyond current size is not an issue. Soil- Ratio Most of waste is delivered in containers, and thus a soil-waste ratio has not been an issue. Compaction Method Most of the waste is disposed in containers. Existing compaction methods for granular materials is adequate. Placement Cessation of nuclear density testing has been recommended and is under consideration by the site. Method does not exist to evaluate void space in containers before and after grouting. Stability & Settlement Environmental Performance Container void space criterion remains uncoupled with cover design. Impact of differential settlement due to spatially variable waste thickness is unresolved. Contractor is currently conducting analysis to address this issue. There are no known problems and no known incidents with monitoring systems outside the landfill envelope. 8

10 Oak Ridge: Environmental Management Management Facility Facility Overview Liner Design Cover Design (Conceptual) Facility Profile: Commenced Operations: 2002 (currently filling) Anticipated Closure Date: Not determined Operating Contractor: Bechtel Jacobs Corporation Regulatory Authority: CERCLA s: Contaminated soils, D&D waste, asbestos, hazardous waste Disposal rate and capacity: 460 tons/d; 3,000,000 tons % Complete 9

11 Landfill Systems Matrix Oak Ridge s EMWMF Element Timeline Future Prognosis Comments Liner Collection System Site employs double liner with secondary liner consisting of geomembrane over compacted clay soil. Geomembrane contribution is ignored in PA, making analysis very conservative. Performance record for composite liners is excellent. There are no known problems and no known incidents with the leachate collection system. System employs gravity drainage to a removal point via piping routed through side slope penetrations. Treatment There are no known problems and no known incidents with the leachate treatment system. Cover Cover has not yet been constructed and therefore monitoring is not yet required. Conceptual cover design has been proposed, but has not been made final. PA assumes 10 mm/yr percolation per year and geomembrane life of 100 yr, which is inconsistent. Volume Control Disposal of wastes outside existing baseline assessment may prove problematic. Current land availability, geometric issues, hydrological constraints, and stakeholder concerns may prevent expansion and availability of disposal capacity. Soil- Ratio Soil-waste ratio evaluated at full-scale using trial sections. Compaction Method Compaction method demonstrated at full-scale using trial sections. Placement Compaction monitoring method has not been rigorously coupled to settlement of cover and potential impacts on long-term cover performance. Relies on judgment of technician rather than on rigorous evaluation criterion. Settlement of waste ill-defined and not clearly related to performance of cover. Strategy to evaluate potential for differential settlement not defined. May affect long-term performance of cover. Stability & Settlement Environmental Performance There are no known problems and no known incidents with monitoring systems outside the landfill envelope. 10

12 Portsmouth Gaseous Diffusion Plant: On-Site Disposal Facility Facility Overview Liner Design Facility Profile: Commenced Operations: Not yet constructed Anticipated Closure Date: To be determined Operating Contractor: To be determined Regulatory Authority: CERCLA or RCRA (to be determined) s: Contaminated soils, D&D waste, diffusers, TSCA wastes, non-hazardous and hazardous solid waste. Disposal rate and capacity: Not yet determined : Conceptual design proposed Cover Design (Conceptual) % Complete 11

13 Landfill Systems Matrix Portsmouth s OSWDF Element Timeline Future Prognosis Comments Liner Collection System A double liner with a secondary composite liner consisting of three layers (geomembrane over GCL over compacted clay soil) is proposed. Performance record for composite liners is excellent. Future prognosis should be excellent with this barrier system. collection system should be made of coarser material than currently suggested by hydraulic conductivity specification. Sumps should be moved to periphery. Both will enhance probability of success over 1000-yr design life. Treatment There are no known problems and no known incidents with the leachate treatment system. Cover Highly heterogeneous waste mass with an abundance of diffusers may lead to differential settlement and impact integrity of the cover. Settlement of waste should be explored carefully during final design. Volume Control The site is not constrained and therefore expansion should not be problematic if waste volumes are larger than anticipated. Soil- Ratio Soil-waste ratio should be evaluated prior to final design to ensure differential settlements will be maintained at acceptable magnitude. Compaction Method Compaction method should be evaluated prior to final design to ensure differential settlements will be maintained at acceptable magnitude. Placement Performance-based methodology should be developed during design for monitoring placement of wastes, particularly large objects that will need to be backfilled or grouted. Method must be tied to adequate support for the final cover. Settlement of highly heterogeneous waste mass with an abundance of diffusers may lead to differential settlement and impact integrity of the cover. Settlement of waste should be explored carefully during final design. Stability & Settlement Environmental Performance systems have not yet been designed. 12

14 Nevada Test Site: Area 5 Facility Overview Liner Design Area 5 uses unlined trenches for disposal. A RCRA C-style composite liner may be installed for a new cell to be constructed for mixed waste. Facility Profile: Commenced Operations: 1961 Anticipated Closure Date: Not determined Operating Contractor: National Security Technologies Regulatory Authority: DOE and State of Nevada s: Contaminated soils, building debris, D&D waste, reactors, decommissioned DOE equipment, military equipment. Some wastes classified. Cover Design Soil cover constructed from natural alluvium available on site. Operational cover is 2.4 m thick. Final cover may include an additional 0.6 m, bringing total thickness to 3.0 m % Complete 13

15 Landfill Systems Matrix NTS Area 5 Element Timeline Future Prognosis Comments Liner Collection System Not Applicable Employs unlined units for LLRW and MLLW. Arid climate & hydrogeologic setting favorable for unlined disposal, but lack of liner may be problematic when permitting new disposal units. Unbiased and independent analysis of appropriate strategy recommended. No leachate collection system exits. As with liner, this issue may become problematic when new cells are permitted. Unbiased and independent analysis of need for liner and leachate collection system is recommended. Treatment Not Applicable treatment system will be needed if leachate collection system is installed. Cover Field trial of cover system is underway. Proposed flexible & natural system advantageous. Importance of defects causing preferential flow paths needs review in context of current knowledge. PA assumes defects do not exist; need method to inspect/repair defects. Volume Control No air space limitations exist. Site can accept waste for foreseeable future. Soil- Ratio 1990 s studies regarding soil-waste ratios and compaction needs should be reviewed in context of current scientific understanding. Procedures may be revised or updated if necessary. Compaction Method 1990 s studies regarding soil-waste ratios and compaction needs should be reviewed in context of current scientific understanding. Procedures may be revised or updated if necessary. Placement Nearly all waste in containers with regimented placement method that minimizes voids. May need to revisit placement strategies if unpacked MLLW disposed in future. Need to review how placement method may affect settlement and distortion of cover. Stability & Settlement Revisit 1990s studies on settlement and impact on cover in context of most recent information. Re-assess cover settlement predictions, and impacts on cover integrity if necessary. Environmental Performance Consider vadose zone monitoring system similar to SRS directly beneath cells. Consider pan lysimeters beneath cells to confirm fluxes assumed in PA. 14

16 Paducah Gaseous Diffusion Plant Facility Overview Liner Design A conceptual design for the OSDF has not yet been created. However, the OSDF would be used to dispose MLLW and thus would need to meet minimum standards in Subtitle C of RCRA. At a minimum, this will require (top to bottom): Cover Design Facility Profile: Commenced Operations: Not constructed Anticipated Closure Date: Not determined Operating Contractor: Paducah Remediation Services Regulatory Authorities: DOE, USEPA, KY Dept. Mgmt. s: Contaminated soils, D&D waste, diffusers, reactors; LLRW and mixed wastes, asbestos Minimum standards in Subtitle C of RCRA will require that the cover system include (top to bottom): - surface layer with treatment to minimize erosion bi t i t i b i % Complete 15

17 Landfill Systems Matrix Paducah Gaseous Diffusion Plant Element Timeline Future Prognosis Comments Liner Collection System CERCLA requires double liner with lower composite liner as minimum standard. Double composite liner similar to Fernald recommended, with GCL incorporated into upper liner to reduce flow to leak detection system. Performance record for composite liners is excellent. CERCLA requires leachate collection system and leak detection system between liners. Coarse rounded stone (> 25 mm) in leachate collection system recommended. May consider secondary leak detection beneath lower liner if sited in brownfield location. Treatment Methods employed for EMWMF should suffice given similarity of plant to Oak Ridge. Methods proposed for Portsmouth should also be evaluated during design. Cover Consider effects of distortion cause by differential settlement over 1000-yr life. Field trial of potential cover systems recommended. Start field trials once preliminary design of OSDF proffered. Volume Control Subtitle D landfill may be used as staging area or for diversion of non-mllw wastes. Either approach will save air space. Recommend adapting waste forecasting and tracking tools employed at EMWMF and SRS for use at PGDP. Soil- Ratio Recommend field trials similar to those at ERDF to identify appropriate soil-waste ratio. Cover support should be basis for evaluating trials. Compaction Method Use landfill compactors similar to those employed at ERDF for compacting non-containerized wastes. Placement Avoid disposing of containers and grouting to extent practical. Embed in soil and compact using performance-based specification to extent practical. Stability & Settlement Environmental Performance Conduct field trials to evaluate waste settlement for different placement scenarios. Use settlement data to define acceptable placement methods. Follow recommendations from USACoE for seismic analysis. Level of performance monitoring will depend on siting location. For a brownfield site, innovative vadose zone monitoring and water quality criteria may need to be proposed. 16

18 Savannah River Site Facility Overview Liner Design Use of liners at SRS depends on type of facility: - slit trenches and engineered trenches (including cast-in-place disposal) unlined - low activity waste vaults concrete floor with water stops and sump Facility Profile: Commenced Operations: 1950s Anticipated Closure Date: Not determined Operating Contractor: Savannah River Nuclear Solutions Regulatory Authority: DOE s: Contaminated soils and D&D debris, TRU waste, decommissioned equipment, naval reactors, mixed wastes, laboratory waste, elemental carbon Cover Design Temporary and final covers are used. Temporary covers vary with type of unit: - slit trenches and engineered trenches surface geomembrane (replaced as needed) For cast-in-place disposal a % Complete 17

19 Landfill Systems Matrix Savannah River Site Area E Element Timeline Future Prognosis Comments Liner Collection System Absence of liners in SRS humid climate may pose problems in the future. Flux from disposal facilities currently estimated. Recommend lysimeters to quantify and validate PA. Consider using liners and treating leachate. Lined units have adequate systems to collect leachate. Treatment No deficiencies exist in leachate treatment. Cover Final cover relies on geosynthetic clay liner (GCL) as primary barrier. Recent studies show that GCLs can be ineffective within a few years of installation. Cover design should be re-evaluated and PA needs to reflect realistic percolation rate. Recommend field trials for proposed cover. Volume Control There is no problem with air space at SRS. Soil- Ratio There is no soil-waste criterion at SRS. Compaction Method Placement Stability & Settlement Environmental Performance s are not compacted at SRS, which may lead to short term settlement problems and difficulty managing runoff. Dynamic compaction planned for final disposition. Settlements expected after dynamic compaction are not well known. Field trial should be conducted. Recommend compaction of soil surrounding waste to reduce settlements and surface distortion during institutional control period. Dynamic compaction should reduce settlement after institutional control period is completed. However, magnitude of settlement and potential for differential settlement ill-defined. Field trials are recommended. Fluxes from unlined trenches are not monitored and are assumed in PA. Recommend that fluxes be monitored to verify assumptions in PA. 18

20 References Benson, C., Albright, W., Ray, D., and Smegal, J. (2008). Review of Disposal Practices at the Savannah River Site, Office of Engineering and Technology, Office of Engineering and Technology (EM-20), US Department of Energy, Washington, DC, 20 July 2008 (DRAFT). Benson, C., Albright, W., Ray, D., and Smegal, J. (2008). Review of the Proposed On-Site Disposal Facility (OSWDF) at the Paducah Gaseous Diffusion Plant, Office of Engineering and Technology, Office of Engineering and Technology (EM-20), US Department of Energy, Washington, DC, 15 July 2008 (DRAFT). Benson, C., Albright, W., Ray, D., and Smegal, J. (2008). Review of Disposal Practices at the Nevada Test Site, Office of Engineering and Technology (EM-20), US Department of Energy, Washington, DC, 15 July Benson, C., Albright, W., Ray, D., and Smegal, J. (2008). Review of the Proposed On-Site Disposal Facility (OSWDF) at the Portsmouth Gaseous Diffusion Plant, Office of Engineering and Technology (EM-20), US Department of Energy, Washington, DC, 25 February Benson, C., Albright, W., Ray, D., and Smegal, J. (2008). Review of the Environmental Management Management Facility (EMWMF) at Oak Ridge National Laboratory. Office of Engineering and Technology (EM-20), US Department of Energy, Washington, DC, 1 February Benson, C., Albright, W., Ray, D., and Smegal, J. (2007). Review of the Idaho CERCLA Disposal Facility (ICDF) at Idaho National Laboratory. Office of Engineering and Technology (EM-20), US Department of Energy, Washington, DC, 5 December Benson, C., Albright, W., and Ray, D. (2007), Evaluating Operational Issues at the Environmental Restoration Disposal Facility at Hanford, Office of Engineering and Technology (EM-20), US Department of Energy, Washington, DC, 17 June

21 Acknowledgement This document was prepared by Craig H. Benson on behalf of the Independent Technical Review Committee on On-Site Disposal Facilities. Support for preparing this document was provided by Mark Gilbertson (DOE-HQ). Dinesh Gupta (DOE-HQ) and Vincent Adams (DOE-HQ) provided constructive comments while this document was being prepared. 20