UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No. ___)*

USEC Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

90333E108

(CUSIP Number)

November 20, 2007

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

o Rule 13d-1(b)
þ Rule 13d-1(c)
o Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

 

 

CUSIP No.		90333E108

CUSIP No.		90333E108

Item 1.

	(a)		Name of Issuer
			USEC Inc.
	(b)		Address of Issuer’s Principal Executive Offices
			2 Democracy Center, 6903 Rockledge Drive, Bethesda, Maryland 20817

Item 2.

(a)

Name of Person Filing

               This statement is jointly filed by and on behalf of each of Corriente Advisors, LLC and Mark L. Hart III. Corriente Advisors acts as an investment adviser to, and manages investment and trading accounts of, other persons, including Corriente Master Fund, L.P. Corriente Advisors may be deemed, through investment advisory contracts or otherwise, to beneficially own securities owned by other persons, including Corriente Master Fund. Mr. Hart is the Chairman and Chief Executive Officer of Corriente Advisors and may be deemed to control Corriente Advisors and beneficially own securities owned by Corriente Advisors.

               Each reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Act or any other purpose, the beneficial owner of any securities covered by this statement.

               Each reporting person may be deemed to be a member of a group with respect to the issuer or securities of the issuer for the purposes of Section 13(d) or 13(g) of the Act. Each reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Act or any other purpose, (i) acting (or has agreed or is agreeing to act) with any other person as a partnership, limited partnership, syndicate, or other group for the purpose of acquiring, holding, or disposing of securities of the issuer or otherwise with respect to the issuer or any securities of the issuer or (ii) a member of any syndicate or group with respect to the issuer or any securities of the issuer.

(b)

Address of Principal Business Office or, if none, Residence

               The address of the principal business office of each reporting person is 201 Main Street, Suite 1800, Fort Worth, Texas 76102.

	(c)		Citizenship
			See Item 4 on the cover page(s) hereto.
	(d)		Title of Class of Securities
			Common Stock
	(e)		CUSIP Number
			90333E108

Item 3. If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is:

	(a)	o	A Broker or dealer registered under Section 15 of the Act (15 U.S.C. 78o).
	(b)	o	A Bank as defined in Section 3(a)(6) of the Act (15 U.S.C. 78c).
	(c)	o	An insurance company as defined in Section 3(a)(19) of the Act (15 U.S.C. 78c).
	(d)	o	An investment company registered under Section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).
	(e)	o	An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);
	(f)	o	An employee benefit plan or endowment fund in accordance with §240.13d- 1(b)(1)(ii)(F);
	(g)	o	A parent holding company or control person in accordance with §240.13d- 1(b)(1)(ii)(G);
	(h)	o	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
	(i)	o	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
	(j)	o	A group, in accordance with §240.13d-1(b)(1)(ii)(J).

Item 4. Ownership.

	(a)		Amount beneficially owned:
			See Item 9 on the cover page(s) hereto.
	(b)		Percent of class:
			See Item 11 on the cover page(s) hereto.
	(c)		Number of shares as to which such person has:

	(i)		Sole power to vote or to direct the vote:
			See Item 5 on the cover page(s) hereto.
	(ii)		Shared power to vote or to direct the vote:
			See Item 6 on the cover page(s) hereto.
	(iii)		Sole power to dispose or to direct the disposition of:
			See Item 7 on the cover page(s) hereto.
	(iv)		Shared power to dispose or to direct the disposition of:
			See Item 8 on the cover page(s) hereto.

Item 5. Ownership of 5% or Less of a Class.

               If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following o.

Item 6. Ownership of More than 5 Percent on Behalf of Another Person

               Corriente Master Fund, L.P. is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities covered by this statement that may be deemed to be beneficially owned by the reporting persons.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

               Not Applicable

Item 8. Identification and Classification of Members of the Group

               Each reporting person may be deemed to be a member of a group with respect to the issuer or securities of the issuer for the purposes of Section 13(d) or 13(g) of the Act. Each reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Act or any other purpose, (i) acting (or has agreed or is agreeing to act) with any other person as a partnership, limited partnership, syndicate, or other group for the purpose of acquiring, holding, or disposing of securities of the issuer or otherwise with respect to the issuer or any securities of the issuer or (ii) a member of any syndicate or group with respect to the issuer or any securities of the issuer.

Item 9. Notice of Dissolution of Group

               Each reporting person may be deemed to be a member of a group with respect to the issuer or securities of the issuer for the purposes of Section 13(d) or 13(g) of the Act. Each reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Act or any other purpose, (i) acting (or has agreed or is agreeing to act) with any other person as a partnership, limited partnership, syndicate, or other group for the purpose of acquiring, holding, or disposing of securities of the issuer or otherwise with respect to the issuer or any securities of the issuer or (ii) a member of any syndicate or group with respect to the issuer or any securities of the issuer.

Item 10. Certifications

     (a) Not Applicable

     (b) By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

     After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

		Date: November 28, 2007		CORRIENTE ADVISORS, LLC
				By:		/s/ James E. Haddaway
				Name:		James E. Haddaway
				Title:		Chief Financial Officer and Chief Operating Officer
				MARK L. HART III
				By:		/s/ Mark L. Hart III
				Name:		Mark L. Hart III

EXHIBIT INDEX

Exhibit		Description of Exhibit
99.1		Joint Filing Agreement

EXHIBIT 99.1

JOINT FILING AGREEMENT

November 28, 2007

     Pursuant to and in accordance with the Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder, each party hereto hereby agrees to the joint filing, on behalf of each of them, of any filing required by such party under Section 13 or Section 16 of the Exchange Act or any rule or regulation thereunder (including any amendment, supplement, and/or exhibit thereto) with the Securities and Exchange Commission (and, if such security is registered on a national securities exchange, also with the exchange), and further agrees to the filing, furnishing, and/or incorporation by reference of this Joint Filing Agreement as an exhibit thereto. This Joint Filing Agreement shall remain in full force and effect until revoked by any party hereto in a signed writing provided to each other party hereto, and then only with respect to such revoking party.

     IN WITNESS WHEREOF, each party hereto, being duly authorized, has caused this Joint Filing Agreement to be executed and effective as of the date first written above.

		Date: November 28, 2007		CORRIENTE ADVISORS, LLC
				By:		/s/ James E. Haddaway
				Name:		James E. Haddaway
				Title:		Chief Financial Officer and Chief Operating Officer
				MARK L. HART III
				By:		/s/ Mark L. Hart III
				Name:		Mark L. Hart III