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| ý | QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934 |
|--------|------------------------------------------------------------------------------------------|

| o | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934 |
|---|-------------------------------------------------------------------------------------------|

| Delaware                 | 52-2107911                           |
|--------------------------|--------------------------------------|
| (State of incorporation) | (I.R.S. Employer Identification No.) |

| Large accelerated filer | o |   | Accelerated filer         | ý |
|-------------------------|---|--------|---------------------------|--------|
| Non-accelerated filer   | o |   | Smaller reporting company | o      |

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| Item 6.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | Exhibits                                                                                                              | 2      |
| Signature                                                                                                                                        | 4                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Exhibit Index                                                                                                                               | 5                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |

|   | 10.1 | Agreement dated May 15, 2012 between United States Enrichment Corporation and Energy Northwest. (a) |
|--------|------|-----------------------------------------------------------------------------------------------------|

|   | 10.2 | Supplement No. 1 dated March 2, 2006 to Power Contract dated July 11, 2000 between Tennessee Valley Authority and United States Enrichment Corporation. (b)(c) |
|--------|------|----------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.3 | Supplement No. 2 dated March 2, 2006 to Power Contract dated July 11, 2000 between Tennessee Valley Authority and United States Enrichment Corporation. (b)(c) |
|--------|------|----------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.4 | Supplement No. 3 dated March 2, 2006 to Power Contract dated July 11, 2000 between Tennessee Valley Authority and United States Enrichment Corporation. (b)(c) |
|--------|------|----------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.5 | Amendatory Agreement (Supplement No. 9) dated May 15, 2012 to the Power Contract between the Tennessee Valley Authority and the United States Enrichment Corporation, dated July 11, 2000, as amended. (a) |
|--------|------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.6 | Confirmation Letter dated May 15, 2012 between United States Enrichment Corporation and the Tennessee Valley Authority. (a) |
|--------|------|-----------------------------------------------------------------------------------------------------------------------------|

|   | 10.7 | Amendment No. 20, dated June 5, 2012, to Contract dated January 14, 1994 between United States Enrichment Corporation, Executive Agent of the United States of America, and Joint Stock Company “Techsnabexport”, Executive Agent of the Russian Federation. (a) |
|--------|------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.8 | Cooperative Agreement dated June 12, 2012 between the U.S. Department of Energy and USEC Inc. and American Centrifuge Demonstration, LLC concerning the American Centrifuge Cascade Demonstration Test Program. (a) |
|--------|------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.9 | Contract dated June 12, 2012 between the U.S. Department of Energy and American Centrifuge Demonstration, LLC. (c) |
|--------|------|--------------------------------------------------------------------------------------------------------------------|

|   | 10.10 | Modification No. 5 dated June 12, 2012, to the Agreement dated June 17, 2002, between DOE and USEC Inc. (c) |
|--------|-------|-------------------------------------------------------------------------------------------------------------|

|   | 10.11 | Summary Sheet for 2012 Non-Employee / Non-Investor Director Compensation. (c) |
|--------|-------|-------------------------------------------------------------------------------|

|   | 10.12 | First Amendment to Fourth Amended and Restated Credit Agreement, dated as of June 1, 2012, among USEC Inc., United States Enrichment Corporation, the lenders party thereto, and JPMorgan Chase Bank, N.A., as administrative and collateral agent, incorporated by reference to Exhibit 10.1 of the Current Report on Form 8-K filed on June 1, 2012 (Commission File number 1-14287). |
|--------|-------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.13 | USEC Inc. Quarterly Incentive Plan, incorporated by reference to Exhibit 10.1 of the Current Report on Form 8-K filed on April 19, 2012 (Commission file number 1-14287). |
|--------|-------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 31.1 | Certification of the Chief Executive Officer pursuant to Rule 13a-14(a)/15d-14(a). |
|--------|------|------------------------------------------------------------------------------------|

|   | 31.2 | Certification of the Chief Financial Officer pursuant to Rule 13a-14(a)/15d-14(a). |
|--------|------|------------------------------------------------------------------------------------|

|   | 32.1 | Certification of CEO and CFO pursuant to 18 U.S.C. Section 1350. (c) |
|--------|------|----------------------------------------------------------------------|

|   | 101 | Consolidated condensed financial statements from the quarterly report on Form 10-Q for the quarter ended June 30, 2012, furnished in interactive data file (XBRL) format. (c) |
|--------|-----|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | ______________________ |
|--------|------------------------|

| (a)   | Certain information has been omitted and filed separately pursuant to a request for confidential treatment under Rule 24b-2. |
|-----------------|------------------------------------------------------------------------------------------------------------------------------|

| (b)   | Includes information previously omitted and filed separately pursuant to confidential treatment under Rule 24b-2. |
|-----------------|-------------------------------------------------------------------------------------------------------------------|

| (c)   | Previously filed with USEC Inc.’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2012. |
|-----------------|------------------------------------------------------------------------------------------------------------|

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|                    | USEC Inc.                                         |
|-------------------------|---------------------------------------------------|
|                    |                                              |   |   |
|                    |                                              |   |   |
|                    |                                              |   |   |
| Date: December 11, 2012 | By:                                               |   /s/ John C. Barpoulis |   |
|                    |                                              | John C. Barpoulis |   |
|                    | Senior Vice President and Chief Financial Officer |
|                    | (Principal Financial Officer)                     |

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|   | 10.1 | Agreement dated May 15, 2012 between United States Enrichment Corporation and Energy Northwest. (a) |
|--------|------|-----------------------------------------------------------------------------------------------------|

|   | 10.5 | Amendatory Agreement (Supplement No. 9) dated May 15, 2012 to the Power Contract between the Tennessee Valley Authority and the United States Enrichment Corporation, dated July 11, 2000, as amended. (a) |
|--------|------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.6 | Confirmation Letter dated May 15, 2012 between United States Enrichment Corporation and the Tennessee Valley Authority. (a) |
|--------|------|-----------------------------------------------------------------------------------------------------------------------------|

|   | 10.7 | Amendment No. 20, dated June 5, 2012, to Contract dated January 14, 1994 between United States Enrichment Corporation, Executive Agent of the United States of America, and Joint Stock Company “Techsnabexport”, Executive Agent of the Russian Federation. (a) |
|--------|------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 10.8 | Cooperative Agreement dated June 12, 2012 between the U.S. Department of Energy and USEC Inc. and American Centrifuge Demonstration, LLC concerning the American Centrifuge Cascade Demonstration Test Program. (a) |
|--------|------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 31.1 | Certification of the Chief Executive Officer pursuant to Rule 13a-14(a)/15d-14(a). |
|--------|------|------------------------------------------------------------------------------------|

|   | 31.2 | Certification of the Chief Financial Officer pursuant to Rule 13a-14(a)/15d-14(a). |
|--------|------|------------------------------------------------------------------------------------|

|   | ______________________ |
|--------|------------------------|

| (a)   | Certain information has been omitted and filed separately pursuant to a request for confidential treatment under Rule 24b-2. |
|-----------------|------------------------------------------------------------------------------------------------------------------------------|