Commitments and Contingencies	3 Months Ended
Mar. 31, 2013
Commitments and Contingencies
Commitments and Contingencies	14. COMMITMENTS AND CONTINGENCIES American Centrifuge Plant Project Funding USEC needs significant additional financing in order to complete the American Centrifuge Plant. USEC believes a loan guarantee under the DOE Loan Guarantee Program, which was established by the Energy Policy Act of 2005, is essential to obtaining the funding needed to complete the ACP. In July 2008, USEC applied under the DOE Loan Guarantee Program for $2 billion in U.S. government guaranteed debt financing for the ACP. Instead of moving forward with a conditional commitment for a loan guarantee, in the fall of 2011, DOE proposed a two-year RD&D program for the project. Refer to Note 4 regarding the RD&D program underway. DOE indicated that USEC's application for a DOE loan guarantee would remain pending during the RD&D program but has given USEC no assurance that a successful RD&D program will result in a loan guarantee. Additional capital beyond the $2 billion of DOE loan guarantee funding that USEC has applied for and USEC's internally generated cash flow will be required to complete the project. USEC has had discussions with Japanese export credit agencies regarding financing up to $1 billion of the cost of completing the ACP, with such potential financing predicated on USEC receiving a DOE loan guarantee. USEC also expects to need at least $1 billion of capital for the project in addition to the DOE loan guarantee and the Japanese export credit agency funding discussed above. The amount of additional capital is dependent on a number of factors, including the amount of any revised cost estimate and schedule for the project, the amount of contingency or other capital DOE may require as part of a loan guarantee, and the amount of the DOE credit subsidy cost that would be required to be paid in connection with a loan guarantee. USEC currently anticipates the sources for this capital to include cash generated by the project during startup, available USEC cash flow from operations and additional third-party capital. USEC expects the additional third-party capital would be raised at the project level, including through the issuance of additional equity participation. USEC has no assurances that it will be successful in obtaining this financing and that the delays and cost increases the Company has experienced will not adversely affect these efforts. USEC is working to identify cost mitigation actions and opportunities for schedule acceleration; however USEC has no assurance that it will be successful. USEC is also engaging with customers regarding ACP sales commitments at SWU prices that support acceptable economics needed to attract capital necessary for the project. However, these efforts are being challenged by current market prices. USEC also is uncertain regarding the amount of internally generated cash flow from operations that USEC will have available to finance the project in light of the delays in deployment of the project and potential requirements for USEC's internally generated cash flow to satisfy its pension and postretirement benefit and other obligations. The amount of capital that USEC is able to contribute to the project going forward will also impact USEC's share of the ultimate ownership of the project, which will likely be reduced as a result of raising equity and other capital to deploy the project. In order to increase the likelihood of a successful financing and deployment of the American Centrifuge project and USEC's participation in such project, USEC is engaged with its advisors and certain stakeholders on alternatives for a possible restructuring of its balance sheet. A restructuring of USEC's balance sheet could adversely affect the holders of USEC common stock through dilution or loss in value. However, USEC has no assurance regarding the outcome of any discussions USEC pursues with creditors or other key stakeholders. Milestones under the 2002 DOE-USEC Agreement On June 12, 2012, USEC and DOE entered into an amendment to the agreement dated June 17, 2002 between DOE and USEC (such agreement, as amended, the "2002 DOE-USEC Agreement"). Under the 2002 DOE-USEC Agreement, USEC and DOE made long-term commitments directed at resolving issues related to the stability and security of the domestic uranium enrichment industry. The agreement provides that USEC will develop, demonstrate and deploy advanced enrichment technology in accordance with milestones and provides for remedies in the event of a failure to meet a milestone under certain circumstances. The June 2012 amendment added two new milestones related to the RD&D program and revised the remaining four milestones under the 2002 DOE-USEC Agreement relating to the financing and operation of the American Centrifuge Plant to be aligned with the RD&D program. In the June 2012 amendment, USEC also granted to DOE an irrevocable, non-exclusive right to use or permit third parties on behalf of DOE to use all centrifuge technology intellectual property ("Centrifuge IP") royalty free for U.S. government purposes (which includes completion of the cascade demonstration test program and national defense purposes, including providing nuclear material to operate commercial nuclear power reactors for tritium production). USEC also granted an irrevocable, non-exclusive license to DOE to use such Centrifuge IP developed at USEC's expense for commercial purposes (including a right to sublicense), which may be exercised only if USEC misses any of the milestones under the 2002 DOE-USEC Agreement or if USEC (or an affiliate or entity acting through USEC) is no longer willing or able to proceed with, or has determined to abandon or has constructively abandoned, the commercial deployment of the centrifuge technology. Such commercial purposes licenses are subject to payment of an agreed upon royalty rate to USEC, which shall not exceed $665 million in the aggregate. The 2002 DOE-USEC Agreement provides DOE with specific remedies if USEC fails to meet a milestone that would materially impact USEC's ability to begin commercial operations of the American Centrifuge Plant on schedule and such delay was within USEC's control or was due to USEC's fault or negligence. These remedies could include terminating the 2002 DOE-USEC Agreement, revoking USEC's access to DOE's U.S. centrifuge technology that USEC requires for the success of the American Centrifuge project and requiring USEC to transfer certain of its rights in the American Centrifuge technology and facilities to DOE, and to reimburse DOE for certain costs associated with the American Centrifuge project. Any of these remedies under the 2002 DOE-USEC Agreement could have a material adverse impact on USEC's business. The 2002 DOE-USEC Agreement provides that if a delaying event beyond the control and without the fault or negligence of USEC occurs which would affect USEC's ability to meet an ACP milestone, DOE and USEC will jointly meet to discuss in good faith possible adjustments to the milestones as appropriate to accommodate the delaying event. USEC's right to continue operating the Paducah GDP under its lease with DOE is not subject to meeting the ACP milestones. In addition, the new 10-year commercial supply agreement entered into on March 23, 2011 with TENEX is not subject to any of the remedies related to the ACP under the 2002 DOE-USEC Agreement. Technical Milestones under the June 2012 Cooperative Agreement The June 2012 cooperative agreement with DOE, as amended most recently on March 15, 2013, includes technical milestones for the RD&D program. DOE has the right to terminate the cooperative agreement if any of the remaining technical milestones are not met. DOE also has the right to terminate the cooperative agreement if USEC materially fails to comply with the other terms and conditions of the cooperative agreement. Failure to meet the technical milestones under the cooperative agreement could provide a basis for DOE to exercise its remedies under the 2002 DOE-USEC Agreement. To date, four milestones have been achieved and five remain. USEC recently achieved, and on May 1, 2013 DOE certified satisfactory completion, of two milestones relating to (1) testing on extended feed rate range and (2) testing machine performance parameters. Both tests demonstrated advanced design features and robustness of the centrifuges to adverse operating conditions. In addition, the cooperative agreement contains non-binding performance indicators that are designed to be achieved throughout the RD&D program and ensure that the RD&D program is on track to achieve the milestones and other program objectives. Although the performance indicators are non-binding, the failure to achieve a performance indicator could cause DOE to take actions that are adverse to USEC. By manufacturing the 120 AC100 centrifuges required for the demonstration cascade, the program has met the third out of five performance indicators. NYSE Listing Notice On May 8, 2012, USEC received notice from the New York Stock Exchange ("NYSE") that the average closing price of its common stock was below the NYSE's continued listing criteria relating to minimum share price. The NYSE listing requirements require that a company's common stock trade at a minimum average closing price of $1.00 over a consecutive 30 trading-day period. In accordance with the NYSE's rules, on May 14, 2012, USEC provided written notice to the NYSE of its intent to cure this deficiency through a reverse stock split. USEC is required to regain compliance with the NYSE's price criteria by no later than its next annual meeting of stockholders if stockholder approval is required as is the case with a reverse stock split. USEC intends to seek stockholder approval for a reverse stock split at its next annual meeting of stockholders, scheduled for June 27, 2013. If USEC's stockholders approve the reverse stock split and USEC effectuates the reverse stock split to cure the condition, the condition will be deemed cured if USEC's closing share price promptly exceeds $1.00 per share, and the price remains above the level for at least the following 30 trading days. Subject to the NYSE's rules, during the cure period, USEC's common stock will continue to be listed and trade on the NYSE, subject to its continued compliance with the NYSE's other applicable listing rules. On April 30, 2013, USEC received notice from the NYSE that the decline in USEC's total market capitalization has caused it to be out of compliance with another of the NYSE's continued listing standards. The NYSE listing requirements require that a company maintain an average market capitalization of not less than $50 million over a consecutive 30 trading-day period where the company's total stockholders' equity is less than $50 million. In mid-April 2013, USEC's average market capitalization fell below $50 million, and USEC had a stockholders' deficit of $472.9 million as of December 31, 2012. In accordance with the NYSE's rules, on May 6, 2013, USEC provided written notice to the NYSE of its intent to cure this deficiency. Under applicable NYSE rules, USEC has 45 days from the receipt of the notice to submit a plan advising the NYSE of definitive action it has taken, or is taking, that would bring it into conformity with the market capitalization listing standards within 18 months of receipt of the letter. USEC's plan will need to outline by quarter how USEC can through either existing or planned initiatives, return to compliance with the listing standards. USEC may not be successful in identifying initiatives that can reasonably be expected to result in the necessary improvements to USEC's stock price and market capitalization or in executing any initiatives that are identified and included in any plan submitted to the NYSE. If the NYSE accepts the plan, USEC's common stock will continue to be listed on the NYSE during the 18 month cure period, subject to the compliance with other NYSE continued listing standards and continued periodic review by the NYSE of USEC's progress with respect to its plan. If the plan is not submitted on a timely basis, is not accepted, or is accepted but USEC does not make progress consistent with the plan during the plan period, USEC will be subject to suspension and delisting from the NYSE. In addition, the NYSE can at any time suspend trading in a security and delist the stock if it deems it necessary for the protection of investors. The NYSE can take accelerated listing action if USEC's common stock trades at levels viewed to be "abnormally low" over a sustained period of time. USEC would also be subject to immediate suspension and de-listing from the NYSE if its average market capitalization is less than $15 million over a consecutive 30 trading-day period or if it were to file or announce an intent to file under any of the sections of the bankruptcy law. Even if USEC meets the numerical listing standards above, the NYSE reserves the right to assess the suitability of the continued listing of a company on a case-by-case basis whenever it deems it appropriate and will consider factors such as unsatisfactory financial conditions and/or operating results or inability to meet debt obligations or adequately finance operations. A fundamental change is triggered under the terms of USEC's convertible notes if USEC's shares of common stock are not listed for trading on any of the NYSE, the American Stock Exchange, the NASDAQ Global Market or the NASDAQ Global Select Market, and the holders of the notes can require USEC to repurchase the notes at par for cash. USEC's receipt of a NYSE continued listing standards notification described above did not trigger a fundamental change. USEC does not have adequate cash to repurchase the notes. A failure by USEC to offer to repurchase the notes or to repurchase the notes after the occurrence of a fundamental change is an event of default under the indenture governing the notes. The occurrence of a fundamental change under the convertible notes that permits the holders of the convertible notes to require a repurchase for cash is an event of default under USEC's credit facility. Accordingly, the exercise of remedies by holders of our convertible notes or lenders under USEC's credit facility as a result of a delisting would have a material adverse effect on USEC's liquidity and financial condition. Potential ERISA Section 4062(e) Liability USEC is in discussions with the Pension Benefit Guaranty Corporation ("PBGC") regarding the impact of USEC's de-lease of the Portsmouth gaseous diffusion facilities and related transition of employees performing government services work to DOE's new decontamination and decommissioning ("D&D") contractor on September 30, 2011. USEC notified the PBGC of this occurrence and the PBGC has informally advised USEC of its preliminary view that the Portsmouth site transition is a cessation of operations that triggers liability under ERISA Section 4062(e) and that its preliminary estimate is that the ERISA Section 4062(e) liability (computed taking into account the plan's underfunding on a termination basis, which amount differs from that computed for GAAP purposes) for the Portsmouth site transition is approximately $130 million. USEC has informed the PBGC that it does not agree that the Portsmouth de-lease and transition of employees constituted a cessation of operations that triggered liability under ERISA Section 4062(e). USEC also disputes the amount of the PBGC's preliminary calculation of the potential ERISA Section 4062(e) liability. In addition, USEC believes that DOE is responsible for a significant portion of any pension costs associated with the transition of employees at Portsmouth. However, USEC has not reached a resolution with the PBGC and USEC has no assurance that the PBGC will agree with it or will not pursue a requirement for it to accelerate funding or take other actions to provide security. USEC could also face a potential significantly greater liability related to a future decision to discontinue activities at Paducah. Legal Matters USEC is subject to various legal proceedings and claims, either asserted or unasserted, which arise in the ordinary course of business. While the outcome of these claims cannot be predicted with certainty, USEC does not believe that the outcome of any of these legal matters will have a material adverse effect on its results of operations, cash flows or financial condition. On June 27, 2011, a complaint was filed in the United States District Court for the Southern District of Ohio, Eastern Division, against USEC by a former Portsmouth GDP employee claiming that USEC owes severance benefits to him and other similarly situated employees that have transitioned or will transition to the DOE D&D contractor. The plaintiff amended its complaint on August 31, 2011 and February 10, 2012, among other things, to limit the purported class of similarly situated employees to salaried employees at the Portsmouth site who transitioned to the D&D contractor and are allegedly eligible for or owed benefits. On October 11, 2012, the United States District Court granted USEC's motion to dismiss the complaint and dismissed Plaintiffs' motion for class certification as moot. The plaintiffs filed an appeal on January 18, 2013. USEC continues to believe that it has meritorious defenses against the suit and has not accrued any amounts for this matter.

14. COMMITMENTS AND CONTINGENCIES

American Centrifuge Plant

Project Funding

USEC needs significant additional financing in order to complete the American Centrifuge Plant. USEC believes a loan guarantee under the DOE Loan Guarantee Program, which was established by the Energy Policy Act of 2005, is essential to obtaining the funding needed to complete the ACP. In July 2008, USEC applied under the DOE Loan Guarantee Program for $2 billion in U.S. government guaranteed debt financing for the ACP. Instead of moving forward with a conditional commitment for a loan guarantee, in the fall of 2011, DOE proposed a two-year RD&D program for the project. Refer to Note 4 regarding the RD&D program underway. DOE indicated that USEC's application for a DOE loan guarantee would remain pending during the RD&D program but has given USEC no assurance that a successful RD&D program will result in a loan guarantee. Additional capital beyond the $2 billion of DOE loan guarantee funding that USEC has applied for and USEC's internally generated cash flow will be required to complete the project. USEC has had discussions with Japanese export credit agencies regarding financing up to $1 billion of the cost of completing the ACP, with such potential financing predicated on USEC receiving a DOE loan guarantee.

USEC also expects to need at least $1 billion of capital for the project in addition to the DOE loan guarantee and the Japanese export credit agency funding discussed above. The amount of additional capital is dependent on a number of factors, including the amount of any revised cost estimate and schedule for the project, the amount of contingency or other capital DOE may require as part of a loan guarantee, and the amount of the DOE credit subsidy cost that would be required to be paid in connection with a loan guarantee. USEC currently anticipates the sources for this capital to include cash generated by the project during startup, available USEC cash flow from operations and additional third-party capital. USEC expects the additional third-party capital would be raised at the project level, including through the issuance of additional equity participation. USEC has no assurances that it will be successful in obtaining this financing and that the delays and cost increases the Company has experienced will not adversely affect these efforts. USEC is working to identify cost mitigation actions and opportunities for schedule acceleration; however USEC has no assurance that it will be successful. USEC is also engaging with customers regarding ACP sales commitments at SWU prices that support acceptable economics needed to attract capital necessary for the project. However, these efforts are being challenged by current market prices. USEC also is uncertain regarding the amount of internally generated cash flow from operations that USEC will have available to finance the project in light of the delays in deployment of the project and potential requirements for USEC's internally generated cash flow to satisfy its pension and postretirement benefit and other obligations. The amount of capital that USEC is able to contribute to the project going forward will also impact USEC's share of the ultimate ownership of the project, which will likely be reduced as a result of raising equity and other capital to deploy the project.

In order to increase the likelihood of a successful financing and deployment of the American Centrifuge project and USEC's participation in such project, USEC is engaged with its advisors and certain stakeholders on alternatives for a possible restructuring of its balance sheet. A restructuring of USEC's balance sheet could adversely affect the holders of USEC common stock through dilution or loss in value. However, USEC has no assurance regarding the outcome of any discussions USEC pursues with creditors or other key stakeholders.

Milestones under the 2002 DOE-USEC Agreement

On June 12, 2012, USEC and DOE entered into an amendment to the agreement dated June 17, 2002 between DOE and USEC (such agreement, as amended, the "2002 DOE-USEC Agreement"). Under the 2002 DOE-USEC Agreement, USEC and DOE made long-term commitments directed at resolving issues related to the stability and security of the domestic uranium enrichment industry.

The agreement provides that USEC will develop, demonstrate and deploy advanced enrichment technology in accordance with milestones and provides for remedies in the event of a failure to meet a milestone under certain circumstances. The June 2012 amendment added two new milestones related to the RD&D program and revised the remaining four milestones under the 2002 DOE-USEC Agreement relating to the financing and operation of the American Centrifuge Plant to be aligned with the RD&D program.

In the June 2012 amendment, USEC also granted to DOE an irrevocable, non-exclusive right to use or permit third parties on behalf of DOE to use all centrifuge technology intellectual property ("Centrifuge IP") royalty free for U.S. government purposes (which includes completion of the cascade demonstration test program and national defense purposes, including providing nuclear material to operate commercial nuclear power reactors for tritium production). USEC also granted an irrevocable, non-exclusive license to DOE to use such Centrifuge IP developed at USEC's expense for commercial purposes (including a right to sublicense), which may be exercised only if USEC misses any of the milestones under the 2002 DOE-USEC Agreement or if USEC (or an affiliate or entity acting through USEC) is no longer willing or able to proceed with, or has determined to abandon or has constructively abandoned, the commercial deployment of the centrifuge technology. Such commercial purposes licenses are subject to payment of an agreed upon royalty rate to USEC, which shall not exceed $665 million in the aggregate.

The 2002 DOE-USEC Agreement provides DOE with specific remedies if USEC fails to meet a milestone that would materially impact USEC's ability to begin commercial operations of the American Centrifuge Plant on schedule and such delay was within USEC's control or was due to USEC's fault or negligence. These remedies could include terminating the 2002 DOE-USEC Agreement, revoking USEC's access to DOE's U.S. centrifuge technology that USEC requires for the success of the American Centrifuge project and requiring USEC to transfer certain of its rights in the American Centrifuge technology and facilities to DOE, and to reimburse DOE for certain costs associated with the American Centrifuge project. Any of these remedies under the 2002 DOE-USEC Agreement could have a material adverse impact on USEC's business.

The 2002 DOE-USEC Agreement provides that if a delaying event beyond the control and without the fault or negligence of USEC occurs which would affect USEC's ability to meet an ACP milestone, DOE and USEC will jointly meet to discuss in good faith possible adjustments to the milestones as appropriate to accommodate the delaying event.

USEC's right to continue operating the Paducah GDP under its lease with DOE is not subject to meeting the ACP milestones. In addition, the new 10-year commercial supply agreement entered into on March 23, 2011 with TENEX is not subject to any of the remedies related to the ACP under the 2002 DOE-USEC Agreement.

Technical Milestones under the June 2012 Cooperative Agreement

The June 2012 cooperative agreement with DOE, as amended most recently on March 15, 2013, includes technical milestones for the RD&D program. DOE has the right to terminate the cooperative agreement if any of the remaining technical milestones are not met. DOE also has the right to terminate the cooperative agreement if USEC materially fails to comply with the other terms and conditions of the cooperative agreement. Failure to meet the technical milestones under the cooperative agreement could provide a basis for DOE to exercise its remedies under the 2002 DOE-USEC Agreement. To date, four milestones have been achieved and five remain. USEC recently achieved, and on May 1, 2013 DOE certified satisfactory completion, of two milestones relating to (1) testing on extended feed rate range and (2) testing machine performance parameters. Both tests demonstrated advanced design features and robustness of the centrifuges to adverse operating conditions.

In addition, the cooperative agreement contains non-binding performance indicators that are designed to be achieved throughout the RD&D program and ensure that the RD&D program is on track to achieve the milestones and other program objectives. Although the performance indicators are non-binding, the failure to achieve a performance indicator could cause DOE to take actions that are adverse to USEC. By manufacturing the 120 AC100 centrifuges required for the demonstration cascade, the program has met the third out of five performance indicators.

NYSE Listing Notice

On May 8, 2012, USEC received notice from the New York Stock Exchange ("NYSE") that the average closing price of its common stock was below the NYSE's continued listing criteria relating to minimum share price. The NYSE listing requirements require that a company's common stock trade at a minimum average closing price of $1.00 over a consecutive 30 trading-day period. In accordance with the NYSE's rules, on May 14, 2012, USEC provided written notice to the NYSE of its intent to cure this deficiency through a reverse stock split. USEC is required to regain compliance with the NYSE's price criteria by no later than its next annual meeting of stockholders if stockholder approval is required as is the case with a reverse stock split. USEC intends to seek stockholder approval for a reverse stock split at its next annual meeting of stockholders, scheduled for June 27, 2013. If USEC's stockholders approve the reverse stock split and USEC effectuates the reverse stock split to cure the condition, the condition will be deemed cured if USEC's closing share price promptly exceeds $1.00 per share, and the price remains above the level for at least the following 30 trading days. Subject to the NYSE's rules, during the cure period, USEC's common stock will continue to be listed and trade on the NYSE, subject to its continued compliance with the NYSE's other applicable listing rules.

On April 30, 2013, USEC received notice from the NYSE that the decline in USEC's total market capitalization has caused it to be out of compliance with another of the NYSE's continued listing standards. The NYSE listing requirements require that a company maintain an average market capitalization of not less than $50 million over a consecutive 30 trading-day period where the company's total stockholders' equity is less than $50 million. In mid-April 2013, USEC's average market capitalization fell below $50 million, and USEC had a stockholders' deficit of $472.9 million as of December 31, 2012. In accordance with the NYSE's rules, on May 6, 2013, USEC provided written notice to the NYSE of its intent to cure this deficiency. Under applicable NYSE rules, USEC has 45 days from the receipt of the notice to submit a plan advising the NYSE of definitive action it has taken, or is taking, that would bring it into conformity with the market capitalization listing standards within 18 months of receipt of the letter. USEC's plan will need to outline by quarter how USEC can through either existing or planned initiatives, return to compliance with the listing standards. USEC may not be successful in identifying initiatives that can reasonably be expected to result in the necessary improvements to USEC's stock price and market capitalization or in executing any initiatives that are identified and included in any plan submitted to the NYSE. If the NYSE accepts the plan, USEC's common stock will continue to be listed on the NYSE during the 18 month cure period, subject to the compliance with other NYSE continued listing standards and continued periodic review by the NYSE of USEC's progress with respect to its plan. If the plan is not submitted on a timely basis, is not accepted, or is accepted but USEC does not make progress consistent with the plan during the plan period, USEC will be subject to suspension and delisting from the NYSE.

In addition, the NYSE can at any time suspend trading in a security and delist the stock if it deems it necessary for the protection of investors. The NYSE can take accelerated listing action if USEC's common stock trades at levels viewed to be "abnormally low" over a sustained period of time. USEC would also be subject to immediate suspension and de-listing from the NYSE if its average market capitalization is less than $15 million over a consecutive 30 trading-day period or if it were to file or announce an intent to file under any of the sections of the bankruptcy law. Even if USEC meets the numerical listing standards above, the NYSE reserves the right to assess the suitability of the continued listing of a company on a case-by-case basis whenever it deems it appropriate and will consider factors such as unsatisfactory financial conditions and/or operating results or inability to meet debt obligations or adequately finance operations.

A fundamental change is triggered under the terms of USEC's convertible notes if USEC's shares of common stock are not listed for trading on any of the NYSE, the American Stock Exchange, the NASDAQ Global Market or the NASDAQ Global Select Market, and the holders of the notes can require USEC to repurchase the notes at par for cash. USEC's receipt of a NYSE continued listing standards notification described above did not trigger a fundamental change. USEC does not have adequate cash to repurchase the notes. A failure by USEC to offer to repurchase the notes or to repurchase the notes after the occurrence of a fundamental change is an event of default under the indenture governing the notes. The occurrence of a fundamental change under the convertible notes that permits the holders of the convertible notes to require a repurchase for cash is an event of default under USEC's credit facility. Accordingly, the exercise of remedies by holders of our convertible notes or lenders under USEC's credit facility as a result of a delisting would have a material adverse effect on USEC's liquidity and financial condition.

Potential ERISA Section 4062(e) Liability

USEC is in discussions with the Pension Benefit Guaranty Corporation ("PBGC") regarding the impact of USEC's de-lease of the Portsmouth gaseous diffusion facilities and related transition of employees performing government services work to DOE's new decontamination and decommissioning ("D&D") contractor on September 30, 2011. USEC notified the PBGC of this occurrence and the PBGC has informally advised USEC of its preliminary view that the Portsmouth site transition is a cessation of operations that triggers liability under ERISA Section 4062(e) and that its preliminary estimate is that the ERISA Section 4062(e) liability (computed taking into account the plan's underfunding on a termination basis, which amount differs from that computed for GAAP purposes) for the Portsmouth site transition is approximately $130 million. USEC has informed the PBGC that it does not agree that the Portsmouth de-lease and transition of employees constituted a cessation of operations that triggered liability under ERISA Section 4062(e). USEC also disputes the amount of the PBGC's preliminary calculation of the potential ERISA Section 4062(e) liability. In addition, USEC believes that DOE is responsible for a significant portion of any pension costs associated with the transition of employees at Portsmouth. However, USEC has not reached a resolution with the PBGC and USEC has no assurance that the PBGC will agree with it or will not pursue a requirement for it to accelerate funding or take other actions to provide security. USEC could also face a potential significantly greater liability related to a future decision to discontinue activities at Paducah.

Legal Matters

USEC is subject to various legal proceedings and claims, either asserted or unasserted, which arise in the ordinary course of business. While the outcome of these claims cannot be predicted with certainty, USEC does not believe that the outcome of any of these legal matters will have a material adverse effect on its results of operations, cash flows or financial condition.

On June 27, 2011, a complaint was filed in the United States District Court for the Southern District of Ohio, Eastern Division, against USEC by a former Portsmouth GDP employee claiming that USEC owes severance benefits to him and other similarly situated employees that have transitioned or will transition to the DOE D&D contractor. The plaintiff amended its complaint on August 31, 2011 and February 10, 2012, among other things, to limit the purported class of similarly situated employees to salaried employees at the Portsmouth site who transitioned to the D&D contractor and are allegedly eligible for or owed benefits. On October 11, 2012, the United States District Court granted USEC's motion to dismiss the complaint and dismissed Plaintiffs' motion for class certification as moot. The plaintiffs filed an appeal on January 18, 2013. USEC continues to believe that it has meritorious defenses against the suit and has not accrued any amounts for this matter.