A cost estimate for site decommissioning was developed by CN employing guidance in NUREG-1757, Vol. 3, Appendix A (NRC, 2006).

CN’s cost estimate represents our best approximation of all direct and indirect costs of decommissioning the facility based on current site conditions. CN’s estimate does not represent either a worst-case decommissioning scenario, or an overly optimistic one, but is intended to be consistent with our knowledge of past decommissioning actions completed, existing facility conditions and actions needed to complete decommissioning and site restoration for unrestricted release and license termination. Consistent with the requirements of NUREG-1757, CN has made the following assumptions in developing decommissioning cost estimates:

• The facility inventory of licensed radioactive materials and wastes have been dispositioned prior to site decommissioning.
• Decommissioning will meet the criteria for unrestricted release consistent with NMED’s request that the Licensee meet a 15 mrem/yr TEDE for a future Resident Farmer Scenario.
• Decommissioning costs exclude the removal and/or disposal of non-radioactive structures and/or materials beyond that necessary to terminate the current NMED radioactive materials license.

The decommissioning cost estimate developed by CN contains a level of detail consistent with guidance presented in NUREG-1757, Volume 3, Appendix A (NRC, 2006) and was developed using a series of cost estimating tables consistent with the format presented in NUREG-1757 and supported by detailed information as presented in this DP. Consistent with NUREG- 1757, the decommissioning cost estimate contains three basic parts (NRC, 2006):

• A facility description, including subsurface.
• The estimated decommissioning costs (including labor costs, non- labor costs, and a contingency factor).
• Identification and justification of the key assumptions used in the decommissioning cost estimate.

The facility description provides the basic context for the cost estimate. It is contained in Appendix E, Table E-1 and includes references to both general and specific supporting information contained in this DP, including:

• License number and type.
• Specific quantities and types of materials authorized by the license (e.g., by specific isotope).
• General discussion of how licensed materials are used in the Licensee’s operations.
• An estimate of the volume of contaminated materials containing residual radioactivity that will require remediation to meet the criteria for license termination.

The decommissioning cost estimate accounts for the costs of all major phases of site decommissioning that are reasonably foreseeable based on existing past history of site use, and past decommissioning actions completed. The decommissioning estimate follows NUREG-1757 guidelines. The basis for the cost estimate is presented in a series of tables in Appendix E in a format consistent with NUREG-1757, including:

• Table E-1: Includes references to sections of the document that comprise the facility description on which the cost estimate is based.
• Table E-2: Indicates that radiologically contaminated facility components were addressed prior to site decommissioning so that the volume of contaminated facility components requiring management is zero.
• Table E-3: Includes the type and estimated volume of the radiological materials and wastes to be generated during site decommissioning.
• Table E-4: Includes estimated waste disposal costs based on the type and volume of wastes present at the site including a portion of the building slab and impacted subsurface soil. Unit disposal costs presented represent the labor and non-labor costs for removal, packaging, transportation and disposal of each waste type based on over 30 years of CN’s and affiliated waste broker’s decommissioning experience.
• Table E-5: Includes a breakdown of labor for planning and execution of site decommissioning in a series of three phases plus reporting and license termination:
  • Phase 1 includes building demolition and removal of non- impacted building structures.
  • Phase 2 includes removal and disposal of non-impacted foundation, concrete and asphalt surfaces, characterization of underlying surface soils and remediation of localized areas of contamination, if present.
  • Phase 3 includes remediation of impacts to subsurface soil in three areas including Cs-137 at the former HRW and residues of uranium ore as locations G95 and G140.
  • Reporting & License Termination will include documenting the decommissioning work completed to demonstrate compliance with a TEDE of 15 mrem/yr and filing additional site documentation required under NMAC to support the Licensees request for license termination.
• Table E-6: Summarizes labor by task, includes labor rates for critical personnel based on applicable CN labor rates (consistent and competitive with industry standard rates) and provides an estimate of decommissioning labor.
• Table E-7: Summarizes equipment necessary to support site radiological monitoring and sampling efforts, presents CN equipment rates (consistent and competitive with industry standard rates) and provides an estimate of radiation monitoring and sampling equipment costs.
• Table E-8: Summarizes estimated laboratory costs based on a reasonable estimate of the numbers of samples projected for site characterization and FSS surveys.
• Table E-9: Summarizes miscellaneous costs including licensing fees and various subcontractor costs for site decommissioning work.
• Table E-10: Summarizes the total estimated site decommissioning cost of $3,064,460 and summarizes the percentage of cost for each primary cost element as part of the total. Additional costs for New Mexico State Taxes and the 25 percent contingency required under NUREG-1757 result in a total estimated decommissioning cost of about $3,859,699.00.

CN’s estimated decommissioning cost is based on the following key assumptions. To the extent that additional information becomes available that may change these assumptions, or may modify the estimated decommissioning cost, an updated cost estimate should be developed. Key assumptions include:

• Site decommissioning costs are applicable to work projected to occur at the initiation of site decommissioning efforts upon NMED approval of the DP and exclude the costs for DP development and pre-decommissioning site preparations.
• Site decommissioning will be initiated following Licensee receipt of NMED approval of the DP and amendment of the Licensee to include the DP.
• In accordance with applicable NMAC, site decommissioning will be completed within two years of the initiation of site decommissioning work based on submittal of the DR and the Licensee’s request for license termination.
• The site buildings have been adequately characterized and demonstrated to meet NMED release criteria for 15 mrem/yr such that Phase 1 building demolition will be completed for non- impacted structures resulting in non-radioactive waste streams of standard C&D debris for recycling and/or disposal. As such, estimated site decommissioning costs include labor and equipment necessary for monitoring building demolition and disposition to confirm the nature of C&D as non-impacted material, but do not include costs for management of C&D as radioactively impacted material.
• Accessible portions of building foundations, concrete and asphalt surfaces have been adequately characterized and demonstrated to meet NMED release criteria for 15 mrem/yr such that Phase 2 removal of foundations, concrete and asphalt surfaces will be completed for non-impacted materials resulting in non-radioactive waste streams of standard C&D debris for recycling and/or disposal. As such, estimated site decommissioning costs include labor and equipment necessary for monitoring of foundation, concrete and asphalt surface removal and disposition to confirm the nature of C&D as non-impacted material, but do not include costs for management of C&D as radioactively impacted material. Cost estimates also include labor and equipment to complete characterization surveys of surface soils underlying foundations, concrete and asphalt surfaces as well as remedial costs for removal of limited isolated areas of impact, if identified, of contaminated soil or concrete as LLRW.
• The extent of subsurface soil impacts for Cs-137 does not require more than the 150 cubic yards of impacted soil estimated for removal as LLRW. Removal of Cs-137 impacted soil will be completed through advancement of a vertical excavation within a pre-defined volume contained by engineering controls to a maximum depth of 30 feet below ground surface. Cost estimates assume that removal is successful in reducing the level of Cs-137 impact in subsurface soil to background or default screening DCGLs for 15 mrem/yr.
• The extent of subsurface impacts from uranium ore residues at G95 and G140 are limited to total volume of less than two cubic yards of impacted soil at depth of less than three feet. Cost estimates assume that removal is successful in reducing the level of uranium residue impact in subsurface soil to background or default screening DCGLs for 15 mrem/yr.
• Following remedial work and a final round of groundwater testing, an FSS will be conducted to document that site conditions meet 15 mrem/yr for unrestricted release. A single DR will be issued to NMED as a draft. NMED will complete review and comment on the draft DR, and the Licensee will file a final DR and request for license termination within 30-days of receipt of NMED comments.

14.3 Financial Mechanism

The financial assurance mechanism being supplied by the Licensee is a Letter of Credit (LOC), an original signed duplicate of the LOC is included in Appendix F. The LOC is irrevocable and renews automatically on an annual basis.