CORRECTING and REPLACING USEC Achieves American Centrifuge RD&D Milestones

Please replace the release with the following corrected version due to multiple revisions.

The corrected release reads:

USEC ACHIEVES AMERICAN CENTRIFUGE RD&D MILESTONES

USEC Inc. (NYSE:USU) announced that over this past weekend a full production-scale cascade of 120-machines achieved 20-machine years of operations at commercial plant specifications. During that performance run, USEC successfully completed three important milestones set by the Department of Energy (DOE) for the American Centrifuge research, development and demonstration (RD&D) program.

“The demonstration cascade is operating as expected, exceeding the SWU production, machine availability and cascade performance criteria established by DOE,” said John K. Welch, USEC president and chief executive officer. “Our teams in Oak Ridge and Piketon rose to the challenge of the RD&D program and are showing once again why they are considered to be the best in the world.

“The RD&D program is designed with DOE to demonstrate the technological readiness of the American Centrifuge to meet national security needs,” added Welch. “We continue to work with DOE and the Congress to determine the American Centrifuge’s role in meeting those needs as we continue to pursue the development and deployment of this important technology.”

The June 2012 cooperative agreement, as amended, that established the RD&D program with DOE includes nine technical milestones for the RD&D program. Six of the milestones have been completed and certified by DOE. The remaining three milestones that have just been completed, subject to DOE certification, involve demonstrating centrifuge manufacturing quality, centrifuge operational reliability and demonstration of sustained production of 340 SWU at commercial conditions for 20-machine years.

Complete documentation supporting successful completion of these three milestones will be submitted to DOE within the month for certification. The RD&D program will continue while USEC completes additional testing with the cascade and a mandatory NRC-required annual inventory of uranium hexafluoride process gas. An independent board of managers provides oversight for the program.

The deployment of the American Centrifuge technology would ensure that the United States has its own indigenous uranium enrichment technology to meet national security needs. With the recent cessation of enrichment at the gaseous diffusion enrichment facility in Paducah, Ky., the United States for the first time in more than 60 years is without its own technology in operation to enrich uranium and today is completely dependent on foreign-controlled technologies for the production of new nuclear fuel that generates almost 20 percent of America’s electricity.

The cooperative agreement, which has been incrementally funded, provides for 80 percent DOE and 20 percent USEC cost sharing for work performed during the period June 1, 2012 through January 15, 2014. On November 20, 2013, USEC and DOE entered into an amendment to the cooperative agreement for an additional $15.7 million in government funding for the funding period November 2 to January 15, 2014, bringing total government funding to $256.9 million. The RD&D program remains under budget and within schedule.

Forward Looking Statements

This press release contains “forward-looking statements” within the meaning of Section 21E of the Securities Exchange Act of 1934 - that is, statements related to future events. In this context, forward-looking statements may address our expected future business and financial performance, and often contain words such as “expects”, “anticipates”, “intends”, “plans”, “believes”, “will” and other words of similar meaning. Forward-looking statements by their nature address matters that are, to different degrees, uncertain. For USEC, particular risks and uncertainties that could cause our actual future results to differ materially from those expressed in our forward-looking statements include, but are not limited to: risks related to the ongoing transition of our business, including uncertainty regarding the transition of the Paducah gaseous diffusion plant and uncertainty regarding the economics of and continued funding for the American Centrifuge project and the potential for a demobilization or termination of the project; the impact of enrichment market conditions, increased project costs and other factors on the economic viability of the American Centrifuge project without additional government support and on our ability to finance the project and the potential for a demobilization or termination of the project; limitations on our ability to provide any required cost sharing under the RD&D program; uncertainty concerning our ability through the RD&D program to demonstrate the technical and financial readiness of the centrifuge technology for commercialization; uncertainty regarding funding for the project following completion of the RD&D program and uncertainty concerning the ultimate success of our efforts to obtain a loan guarantee from DOE and other financing for the American Centrifuge project or additional government support for the project and the timing and terms thereof and the potential for a demobilization or termination of the project if additional government funding or other additional government support is not in place at the end of the RD&D program; potential changes in our anticipated ownership of or role in the American Centrifuge project, including as a result of the need to raise additional capital to finance the project; the impact of actions we have taken or may take to reduce spending on the American Centrifuge project, including the potential loss of key suppliers and employees, and impacts to cost and schedule; the potential for DOE to seek to terminate or exercise its remedies under the RD&D cooperative agreement or June 2002 DOE-USEC agreement; changes in U.S. government priorities and the availability of government funding, including loan guarantees; and other risks and uncertainties discussed in our filings with the Securities and Exchange Commission, including our Annual Report on Form 10-K and quarterly reports on Form 10-Q, which are available on our website at www.usec.com. We do not undertake to update our forward-looking statements except as required by law.