Agreement between the U.S. Department of Energy and the United States Enrichment Corporation Concerning the Temporary Lease of Certain Facilities In Support of the American Centrifuge Program

EXHIBIT 10.66

Agreement between the U.S. Department of Energy and
the United States Enrichment Corporation
Concerning the Temporary Lease of Certain Facilities
In Support of the American Centrifuge Program

     THIS AGREEMENT between the U.S. Department of Energy and the United States Enrichment Corporation Concerning the Temporary Lease of Certain Facilities in Support of the American Centrifuge Program (Agreement) is made and entered into by and between the U.S. Department of Energy (“DOE”) and the United States Enrichment Corporation (“USEC”), a Delaware corporation.

     WHEREAS, USEC leases portions of the Portsmouth Gaseous Diffusion Plant located in Piketon, Ohio (“PORTS”) and portions of the Paducah Gaseous Diffusion Plant located in Paducah, Kentucky (“PGDP”) from DOE pursuant to a Lease Agreement dated July 1, 1993 (the “GDP Lease”);

     WHEREAS, DOE and USEC entered into an Agreement dated June 17, 2002, (“the DOE-USEC Agreement”) to, inter alia, “[f]acilitate the deployment of new, cost-effective advanced enrichment technology in the U.S. on a rapid schedule” (the DOE-USEC Agreement”);

     WHEREAS, the DOE-USEC Agreement establishes agreed upon milestones for the demonstration and deployment of advanced enrichment technology by USEC; and

     WHEREAS, in order to meet the DOE-USEC Agreement milestones, USEC has requested that the leasehold under the GDP Lease be expanded.

     NOW, THEREFORE, DOE and USEC hereby agree as follows:

   1. In accordance with Section 3.4 of the GDP Lease, DOE hereby consents, subject to the conditions set forth in this Agreement, to expand the GDP Lease to include the following buildings as more fully defined in Attachment 1 hereto (collectively referred to as the “Lead Cascade Facilities”):

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Activities in the Lead Cascade Facilities shall be conducted in compliance with applicable requirements under the National Environmental Policy Act (NEPA), the Price-Anderson Amendments Act of 1988, and any other applicable statutory or regulatory requirements.

USEC hereby withdraws its previous request, dated January 24, 2003, to lease Building X-7745R (Attachment 2).

   2. Exhibit A of the GDP Lease is amended to include the Lead Cascade Facilities as more fully described in Attachment 1 to this Agreement which shall be effective for each facility or portion of a facility as of the date agreed to by USEC and the DOE Lease Administrator for the transition of the facilities to USEC. Upon the effective date of the lease of Building X-3001 at PORTS, the temporary lease of portions of Building X-3001 at PORTS pursuant to DOE’s letter to USEC, dated September 12, 2003 (Attachment 3), shall expire. The temporary lease of Building X-3002 at PORTS shall remain in effect until Building X-3002 is returned to DOE in accordance with DOE’s letter to USEC dated September 12, 2003. Except as provided in paragraph 3 below, the temporary lease of the Lead Cascade Facilities shall expire upon the execution of a commercial plant lease or other instrument that incorporates the Lead Cascade Facilities; the expiration of the license granted by the NRC for the operation of the Lead Cascade ; or June 30, 2009, whichever event occurs first. Unless a commercial plant lease or other instrument that incorporates the Lead Cascade Facilities has been executed, all Turnover Requirements are expected to be completed no later than the expiration of the Temporary lease. This temporary lease of the Lead Cascade Facilities may be renewed or extended by mutual agreement of DOE and USEC.

   3. In accordance with the terms and conditions of the DOE-USEC Agreement, in the event it is determined that USEC fails to meet a milestone and that a delay in meeting the milestone has a material impact on USEC’s ability to begin commercial operations at the new plant on schedule and that the cause of the delay was not beyond the control or without the fault or negligence of USEC, then USEC, at DOE’s request, will return the Lead Cascade Facilities in accordance with the GDP Lease and regulatory requirements on a schedule proposed by USEC and approved by DOE. Notwithstanding any expiration, conclusion or termination of this Agreement or the GDP Lease, paragraphs 7 and 8 and Attachment 4 of this Agreement (“Lead Cascade Capital Improvement and Personal Property to be Removed by USEC”) shall survive any such termination,

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expiration, revocation or relinquishment of this lease Agreement or the GDP Lease. In the event of termination, expiration, revocation or relinquishment of this temporary lease, USEC shall promptly commence the return of all Lead Cascade Facilities to DOE in accordance with paragraphs 7 and 8. In the event USEC fails to return all the Lead Cascade Facilities in accordance with paragraphs 7 and 8 below, USEC shall reimburse DOE for DOE’s costs, including, but not limited to, costs related to the removal of Capital Improvements (provided such Capital Improvements are removed) and contaminated personal property (including any Material of Environmental Concern) and any incremental decontamination and decommissioning costs incurred by DOE in performing any obligation that was to be performed by USEC under paragraphs 7 and 8 of this Agreement as permitted under paragraph 9.

   4. Except for the material that USEC agreed to relocate in accordance with DOE’s September 12, 2003, letter at USEC’s expense, DOE will remove DOE equipment and wastes currently located in the Lead Cascade Facilities (“GCEP Clean up Work”), at DOE’s expense, subject to the availability of appropriated funds. USEC will perform such portion of this work for DOE under the Memorandum of Agreement between DOE and USEC for Services, Exhibit F to the Lease (“Services MOA”), or other appropriate contractual vehicle, without fee or profit with DOE reimbursing USEC’s reasonable and allocable direct and indirect costs. USEC’s work under the Services MOA will be performed in accordance with separate Work Authorization(s) agreed to by DOE and USEC, or other appropriate contractual vehicle. USEC may request to retain equipment, parts or materials located in the Lead Cascade Facilities for use in connection with USEC’s American Centrifuge Program; upon DOE’s consent this personal property shall be included under the requirements of Attachment 4 and be subject to paragraphs 7 and 8 below. All other equipment and material will be dispositioned in accordance with DOE direction at DOE’s expense, or, in the absence of DOE direction, DOE’s personal property (including any Material of Enviro