AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON FEBRUARY 2, 1999.

                                    Registration No. 333-_______________________
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                             -----------------------
                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                             -----------------------

                                    USEC Inc.
             (Exact name of registrant as specified in its charter)

                    DELAWARE                               52-2107911
          (State or other jurisdiction of                (IRS Employer
           incorporation or organization)              Identification No.)

                     2 DEMOCRACY CENTER
                     6903 ROCKLEDGE DRIVE
                     BETHESDA, MARYLAND                  20817
          (Address of principal executive offices)     (Zip Code)

                      USEC Inc. 1999 EQUITY INCENTIVE PLAN
                   USEC Inc. 1999 EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the Plans)

                              HENRY Z SHELTON, JR.
                SENIOR VICE PRESIDENT AND CHIEF FINANCIAL OFFICER
                                    USEC Inc.
                               2 DEMOCRACY CENTER
                              6903 ROCKLEDGE DRIVE
                            BETHESDA, MARYLAND 20817
                     (Name and address of agent for service)

                                 (301) 564-3200
          (Telephone number, including area code, of agent for service)

                                   COPIES TO:

                              PANKAJ K. SINHA, ESQ.
                    SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP
                           1440 NEW YORK AVENUE, N.W.
                             WASHINGTON, D.C. 20005
                            ------------------------

CALCULATION OF REGISTRATION FEE =================================================================================================== Proposed Proposed Maximum Maximum Title of Securities Amount Offering Aggregate Amount of to be to be Price Offering Registration Registered Registered(1) per Share(2) Price(2) Fee - ------------------- ------------- ------------ --------- ------------ Common stock, $.10 par value 11,500,000 shares $14.75 $169,625,000 $47,156 =================================================================================================== (1) We are registering 9,000,000 shares pursuant to the USEC Inc. 1999 Equity Incentive Plan and 2,500,000 shares pursuant to the USEC Inc. 1999 Employee Stock Purchase Plan. This registration statement shall also cover any additional shares of common stock which become issuable under the USEC Inc. 1999 Equity Incentive Plan and the USEC Inc. 1999 Employee Stock Purchase Plan by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without receipt by USEC Inc. ("USEC") of consideration which results in an increase in the number of the outstanding shares of USEC's common stock. (2) Pursuant to Rule 457(c) and 457(h) of the Securities Act of 1933, as amended (the "Securities Act"), the proposed maximum offering price and registration fee are based on the high and low selling prices per share of USEC's common stock on January 29, 1999, as reported on the New York Stock Exchange Composite Tape. ===================================================================================================
2 PART I INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS The information specified by Item 1 and Item 2 of Part I of Form S-8 is omitted from this filing in accordance with the provisions of Rule 428 under the Securities Act and the introductory note to Part 1 of Form S-8. The documents containing the information specified in Part I will be delivered to the participants in the plans covered by this registration statement as required by Rule 428(b). PART II INFORMATION REQUIRED IN THE REGISTRATION STATEMENT Item 3. Incorporation of Documents by Reference --------------------------------------- The Securities and Exchange Commission (the "SEC") allows us to "incorporate by reference" the information we file with them, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this registration statement, and information that we file later with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Securities and Exchange Act of 1934, as amended (the "Exchange Act"), until such time as this registration statement is no longer in effect. (a) Our Annual Report on Form 10-K for the fiscal year ended June 30, 1998; (b) Our Quarterly Reports on Form 10-Q for the quarters ended September 30, 1998 and December 31, 1998; and (c) The description of our common stock contained in our Registration Statement No. 333-57955 on Form S-1 filed with the SEC on June 29, 1998 and incorporated by reference in our Registration Statement on Form 8-A dated July 8, 1998 (File No. 001-14287). You may request a copy of any filings referred to above (excluding exhibits), at no cost, by contacting us at the following address: Investor Relations USEC Inc. 2 Democracy Center 6903 Rockledge Drive Bethesda, Maryland 20817 Telephone: (301) 564-3200 3 Item 4. Description of Securities ------------------------- Not Applicable. Item 5. Interests of Named Experts and Counsel -------------------------------------- Not Applicable. Item 6. Indemnification of Directors and Officers ----------------------------------------- Section 145 of the General Corporation Law of the State of Delaware (the "DGCL") empowers a Delaware corporation to indemnify any person who was or is a party to or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation) by reason of the fact that such person is or was a director, officer, employee or agent of such corporation, or is or was serving at the request of such corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise. The indemnity may include expenses (including attorney's fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by such person in connection with such action, suit or proceeding, provided that such person acted in good faith and in a manner such person reasonably believed to be in or not opposed to the best interests of the corporation and, with respect to any criminal action or proceeding, had no reasonable cause to believe such person's conduct was unlawful. A Delaware corporation may indemnify directors, officers, employees and other agents of such corporation in an action by or in the right of the corporation under the same conditions, except that no indemnification shall be made if such person is adjudged to be liable to the corporation. Where a director, officer, employee or agent of the corporation is successful on the merits or otherwise in the defense of any action, suit or proceeding referred to in this Item 6 or in defense of any claim, issue or matter herein, the corporation must indemnify such person against the expenses (including attorney's fees) which he or she actually and reasonably incurred in connection therewith. Both our By-Laws and the Certificate of Incorporation require us to indemnify each of our directors and officers to the fullest extent permitted by law, subject to certain exceptions, in connection with any actual or threatened action or proceeding arising out of his or her service to us or to other organizations at our request. As permitted by Section 102(b)(7) of the DGCL, our Certificate of Incorporation also contains a provision eliminating the personal liability of a director to USEC or our shareholders for monetary damages for breach of fiduciary duty as a director, subject to certain exceptions. Item 7. Exemption from Registration Claimed ----------------------------------- Not Applicable. Item 8. Exhibits -------- 4 Exhibit Number Exhibit - ------- ------- 4.1 USEC Inc. 1999 Equity Incentive Plan 4.2 USEC Inc. 1999 Employee Stock Purchase Plan 5.1 Opinion of Skadden, Arps, Slate, Meagher & Flom LLP 23.1 Consent of Arthur Andersen LLP, independent public accountants, with respect to the financial statements of USEC Inc. 23.2 Consent of Skadden, Arps, Slate, Meagher & Flom LLP (included in the Opinion filed as Exhibit 5.1) 24.1 Power of Attorney (included on the signature page) Item 9. Undertakings ------------ A. The undersigned registrant hereby undertakes: (1) to file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement: (i) to include any prospectus required by Section 10(a)(3) of the Securities Act; (ii) to reflect in the prospectus any facts or events arising after the effective date of this registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in this registration statement; and (iii) to include any material information with respect to the plan of distribution not previously disclosed in this registration statement or any material change to such information in this registration statement; provided, however, that clauses (1)(i) and (1)(ii) shall not apply if the information required to be included in a post-effective amendment by those clauses is contained in periodic reports filed by USEC pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference into this registration statement; (2) that for the purpose of determining any liability under the Securities Act each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof; and (3) to remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the USEC Inc. 1999 Equity Incentive Plan and/or the USEC Inc. 1999 Employee Stock Purchase Plan. B. The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of USEC's 5 annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act that is incorporated by reference into this registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. C. Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers or controlling persons of USEC pursuant to the indemnification provisions summarized in Item 6 or otherwise, USEC has been advised that, in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by USEC of expenses incurred or paid by a director, officer, or controlling person of USEC in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, USEC will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue. 6 SIGNATURES Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Bethesda, Maryland on the 2nd day of February, 1999. USEC INC. By: /s/ William H. Timbers, Jr. ---------------------------- William H. Timbers, Jr. President and Chief Executive Officer POWER OF ATTORNEY AND SIGNATURES We, the undersigned officers and directors of USEC Inc., hereby severally constitute and appoint William H. Timbers, Jr. and Henry Z Shelton, Jr., and each of them singly, our true and lawful attorneys, with full power to them and each of them singly, to sign for us in our names in the capacities indicated below, all pre-effective and post-effective amendments to this registration statement, and generally to do all things in our names and on our behalf in such capacities to enable USEC Inc. to comply with the provisions of the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission. Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed below by the following persons in the capacities and on the dates indicated.
Name/Signature Title Date - -------------- ------ ------ /s/ James R. Mellor Chairman of the Board February 2, 1999 - --------------------------- and Director James R. Mellor /s/ Joyce F. Brown, Ph.D. Director February 2, 1999 - --------------------------- Joyce F. Brown, Ph.D. /s/ Frank V. Cahouet Director February 2, 1999 - --------------------------- Frank V. Cahouet /s/ John R. Hall Director February 2, 1999 - --------------------------- John R. Hall /s/ Dan T. Moore, III Director February 2, 1999 - --------------------------- Dan T. Moore, III /s/ William H. White Director February 2, 1999 - --------------------------- William H. White /s/ William H. Timbers, Jr. President and Chief Executive February 2, 1999 - --------------------------- Officer (Principal Executive William H. Timbers, Jr. Officer) and Director /s/ Henry Z Shelton, Jr. Senior Vice President and Chief February 2, 1999 - --------------------------- Financial Officer (Principal Henry Z Shelton, Jr. Financial and Accounting Officer)
7 EXHIBIT INDEX ------------- Exhibit Number Exhibit - ------- ------- 4.1 USEC Inc. 1999 Equity Incentive Plan 4.2 USEC Inc. 1999 Employee Stock Purchase Plan 5.1 Opinion of Skadden, Arps, Slate, Meagher & Flom LLP 23.1 Consent of Arthur Andersen LLP, independent public accountants, with respect to the financial statements of USEC Inc. 23.2 Consent of Skadden, Arps, Slate, Meagher & Flom LLP (included in the Opinion filed as Exhibit 5.1) 24.1 Power of Attorney (included on the signature page) 8

                                                                     Exhibit 4.1


                      USEC INC. 1999 EQUITY INCENTIVE PLAN

SECTION 1.

     PURPOSE. The purposes of the USEC Inc. 1999 Equity Incentive Plan (the
"Plan") are to promote the interests of USEC Inc. (the "Company") and its
shareholders by (i) attracting and retaining key employees, consultants and
non-employee directors of the Company and its Affiliates; (ii) motivating such
individuals by means of performance-related incentives to achieve long-range
performance goals; (iii) enabling such individuals to participate in the
long-term growth and financial success of the Company; and (iv) linking
compensation to the long-term interests of shareholders. With respect to any
awards granted under the Plan that are intended to comply with the requirements
of "performance-based compensation" under Section 162(m) of the Code (as defined
below), the Plan shall be interpreted in a manner consistent with such
requirements.

SECTION 2.

     DEFINITIONS. As used in the Plan, the following terms shall have the
meanings set forth below:

          "Affiliate" shall mean (i) any entity that, directly or indirectly, is
     controlled by the Company, (ii) any entity in which the Company has a
     significant equity interest and (iii) an affiliate of the Company, as
     defined in Rule 12b-2 promulgated under Section 12 of the Exchange Act, in
     each case as determined by the Committee.

          "Award" shall mean any Option, Restricted Stock Award, Restricted
     Stock Unit, Other Stock-Based Award or Performance Award.

          "Award Agreement" shall mean any written agreement, contract, or other
     instrument or document evidencing any Award, which may, but need not, be
     executed or acknowledged by a Participant.

          "Board" shall mean the Board of Directors of the Company.

          "Cause" shall mean, unless otherwise defined in the applicable Award
     Agreement, (i) the engaging by the Participant in willful misconduct that
     is injurious to the Company or its Affiliates, (ii) the embezzlement or
     misappropriation of funds or property of the Company or its Affiliates by
     the Participant, or the conviction of the Participant of a felony or the
     entrance of a plea of guilty or nolo contendere by the Participant to a
     felony, or (iii) the willful failure or refusal by the Participant to
     substantially perform his or her duties or responsibilities that continues
     after being brought to the attention of the Participant (other than any
     such failure resulting from the Participant's incapacity due to
     Disability). For purposes of this paragraph, no act, or failure to act, on
     the Participant's part shall be considered "willful" unless done, or
     omitted to be done, by him or her not in good faith and without reasonable
     belief that his or her action or omission was in the best interest of the
     Company. Any determination of Cause shall be made by the Committee in its
     sole discretion. Any such determination shall be final and binding on a
     Participant.

          "Change in Control" shall mean, unless otherwise defined in the
     applicable Award Agreement, a change in control of the Company, which will
     be deemed to have occurred if:

          (i) any "Person," as such term is used in Sections 13(d) and 14(d) of
     the Exchange Act (other than (A) the Company, (B) any trustee or other
     fiduciary holding securities under an employee benefit plan of the Company,
     and (C) any corporation owned, directly or indirectly, by the shareholders
     of the Company in substantially the same proportions as their ownership of
     Shares), is or becomes the "beneficial owner" (as defined in Rule 13d-3
     under the Exchange Act), directly or indirectly, of securities of the
     Company (not including any securities acquired directly from the Company or
     its Affiliates) representing 25% or more of the combined voting power of
     the Company's then outstanding voting securities;

          (ii) the following individuals cease for any reason to constitute a
     majority of the number of directors then serving: individuals who, on the
     effective date (as defined in Section 16(a) of the Plan), constitute the
     Board and any new director (other than a director whose initial assumption
     of office is in connection with an actual or threatened election contest,

     including but not limited to a consent solicitation, relating to the
     election of directors of the Company) whose appointment or election by the
     Board or nomination for election by the Company's shareholders was approved
     or recommended by a vote of at least two-thirds (2/3) of the directors then
     still in office who either were directors on the effective date of the Plan
     or whose appointment, election or nomination for election was previously so
     approved or recommended;

          (iii) there is consummated a merger or consolidation of the Company or
     any direct or indirect subsidiary of the Company with any other
     corporation, other than (A) a merger or consolidation that would result in
     the voting securities of the Company outstanding immediately prior thereto
     continuing to represent (either by remaining outstanding or by being
     converted into voting securities of the surviving or parent entity) more
     than 60% of the combined voting power of the voting securities of the
     Company or such surviving or parent entity outstanding immediately after
     such merger or consolidation or (B) a merger or consolidation effected to
     implement a recapitalization of the Company (or similar transaction) in
     which no "person" (as defined above), directly or indirectly, acquired 40%
     or more of the combined voting power of the Company's then outstanding
     securities (not including any securities acquired directly from the Company
     or its Affiliates); or

          (iv) the shareholders of the Company approve a plan of complete
     liquidation of the Company or there is consummated an agreement for the
     sale or disposition by the Company of all or substantially all of the
     Company's assets (or any transaction having a similar effect), other than a
     sale or disposition by the Company of all or substantially all of the
     Company's assets to an entity, at least 60% of the combined voting power of
     the voting securities of which are owned by shareholders of the Company in
     substantially the same proportions as their ownership of the Company
     immediately prior to such sale.

          "Code" shall mean the Internal Revenue Code of 1986, as amended from
     time to time.

          "Committee" shall mean a committee of the Board (which may include the
     entire Board) designated by the Board to administer the Plan. The Committee
     shall be the Compensation Committee or a sub-committee thereof, unless the
     Board shall appoint another committee to administer the Plan.
     Notwithstanding the foregoing, for purposes of discretionary awards granted
     to Non-Employee Directors pursuant to Section 10 of the Plan, references to
     the Committee shall be deemed to be references to the Board.

          "Covered Officer" shall mean at any date (i) any individual who, with
     respect to the previous taxable year of the Company, was a "covered
     employee" of the Company within the meaning of Section 162(m); provided,
     however, that the term "Covered Officer" shall not include any such
     individual who is designated by the Committee, in its discretion, at the
     time of any Award or at any subsequent time, as reasonably expected not to
     be such a "covered employee" with respect to the current taxable year of
     the Company and (ii) any individual who is designated by the Committee, in
     its discretion, at the time of any Award or at any subsequent time, as
     reasonably expected to be such a "covered employee" with respect to the
     current taxable year of the Company or with respect to the taxable year of
     the Company in which any applicable Award will be paid.

          "Disability" shall mean, unless otherwise defined in the applicable
     Award Agreement, a disability that would qualify as such under the
     Company's then current long-term disability plan.

          "Employee" shall mean an employee of the Company or of any Affiliate.

          "Exchange Act" shall mean the Securities Exchange Act of 1934, as
     amended.

          "Fair Market Value" with respect to the Shares, as of any date, shall
     mean (i) the closing sales price of the Shares on the New York Stock
     Exchange, or any other such exchange on which the shares are traded, on
     such date, or in the absence of reported sales on such date, the closing
     sales price on the immediately preceding date on which sales were reported
     or (ii) in the event there is no public market for the Shares, the fair
     market value as determined, in good faith, by the Committee in its sole
     discretion.

          "Incentive Stock Option" shall mean an option to purchase Shares from
     the Company that is granted under Section 6 of the Plan and that is
     intended to meet the requirements of Section 422 of the Code or any
     successor provision thereto.

          "Non-Qualified Stock Option" shall mean an option to purchase Shares
     from the Company that is granted under Section 6 of the Plan and that is
     not intended to be an Incentive Stock Option.

          "Non-Employee Director" shall mean a member of the Board who is not an
     employee of the Company or any of its Affiliates.

                                       2

          "Option" shall mean an Incentive Stock Option or a Non-Qualified Stock
     Option.

          "Other Stock-Based Award" shall mean any award granted under Section 9
     of the Plan.

          "Participant" shall mean any Employee, Non-Employee Director or
     consultant who receives an Award under the Plan.

          "Performance Award" shall mean any right granted under Section 8 of
     the Plan.

          "Person" shall mean any individual, corporation, partnership,
     association, joint-stock company, trust, unincorporated organization,
     government or political subdivision thereof or other entity.

          "Restricted Stock" shall mean any Share granted under Section 7 of the
     Plan.

          "Restricted Stock Unit" shall mean any unit granted under Section 7 of
     the Plan.

          "Retirement" shall mean, unless otherwise defined in the applicable
     Award Agreement, retirement of a Participant from the employ or service of
     the Company and any of its Affiliates in accordance with the terms of the
     applicable Company retirement plan or, if a Participant is not covered by
     any such plan, retirement on or after such Participant's 65th birthday.

          "SEC" shall mean the Securities and Exchange Commission or any
     successor thereto and shall include the staff thereof.

          "Section 16" shall mean Section 16 of the Exchange Act and the rules
     promulgated thereunder and any successor provision thereto as in effect
     from time to time.

          "Section 162(m) shall mean Section 162(m) of the Code and the rules
     promulgated thereunder or any successor provision thereto as in effect from
     time to time.

          "Shares" shall mean shares of the common stock, $0.10 par value, of
     the Company, or such other securities of the Company as may be designated
     by the Committee from time to time.

          "Substitute Awards" shall mean Awards granted solely in assumption of,
     or in substitution for, outstanding awards previously granted by a company
     acquired by the Company or with which the Company combines.

SECTION 3.

ADMINISTRATION.

     (a) Authority of Committee. The Plan shall be administered by the
Committee. Subject to the terms of the Plan and applicable law, and in addition
to other express powers and authorizations conferred on the Committee by the
Plan, the Committee shall have full power and authority to: (i) designate
Participants; (ii) determine the type or types of Awards to be granted to a
Participant; (iii) determine the number of Shares to be covered by, or with
respect to which payments, rights, or other matters are to be calculated in
connection with, Awards; (iv) determine the terms and conditions of any Award;
(v) determine whether, to what extent, and under what circumstances Awards may
be settled, or exercised in cash, Shares, other securities, other Awards or
other property, or canceled, forfeited, or suspended and the method or methods
by which Awards may be settled, exercised, canceled, forfeited, or suspended;
(vi) determine whether, to what extent, and under what circumstances cash,
Shares, other securities, other Awards, other property, and other amounts
payable with respect to an Award shall be deferred either automatically or at
the election of the holder thereof or of the Committee; (vii) interpret and
administer the Plan and any instrument or agreement relating to, or Award made
under, the Plan; (viii) establish, amend, suspend, or waive such rules and
regulations and appoint such agents as it shall deem appropriate for the proper
administration of the Plan; and (ix) make any other determination and take any
other action that the Committee deems necessary or desirable for the
administration of the Plan.

     (b) Committee Discretion Binding. Unless otherwise expressly provided in
the Plan, all designations, determinations, interpretations, and other decisions
under or with respect to the Plan or any Award shall be within the sole

                                       3

discretion of the Committee, may be made at any time and shall be final,
conclusive, and binding upon all Persons, including the Company, any Affiliate,
any Participant, any holder or beneficiary of any Award, any Employee, any
Non-Employee Director and any consultant.

     (c) Delegation. Subject to the terms of the Plan and applicable law, the
Committee may delegate to one or more officers or managers of the Company or any
Affiliate, or to a committee of such officers or managers, the authority,
subject to such terms and limitations as the Committee shall determine, to grant
Awards to, or to cancel, modify or waive rights with respect to, or to alter,
discontinue, suspend, or terminate Awards held by, Participants who are not
officers or directors of the Company for purposes of Section 16 or who are
otherwise not subject to such Section.

     (d) No Liability. No member of the Board or Committee shall be liable for
any action taken or determination made in good faith with respect to the Plan or
any Award granted hereunder.

SECTION 4.

SHARES AVAILABLE FOR AWARDS.

     (a) Shares Available. Subject to adjustment as provided in Section 4(b),
the number of Shares with respect to which Awards may be granted under the Plan
shall be 9,000,000 and the number of Shares with respect to which Awards (other
than Options) may be granted under the Plan shall be 2,250,000. If, after the
effective date of the Plan, any Shares covered by an Award granted under the
Plan, or to which such an Award relates, are forfeited, or if such an Award is
settled for cash or otherwise terminates or is canceled without the delivery of
Shares, then the Shares covered by such Award, or to which such Award relates,
or the number of Shares otherwise counted against the aggregate number of Shares
with respect to which Awards may be granted, to the extent of any such
settlement, forfeiture, termination or cancellation, shall again become Shares
with respect to which Awards may be granted. In the event that any Option or
other Award granted hereunder is exercised through the delivery of Shares or in
the event that withholding tax liabilities arising from such Award are satisfied
by the withholding of Shares by the Company, the number of Shares available for
Awards under the Plan shall be increased by the number of Shares so surrendered
or withheld. Notwithstanding the foregoing and subject to adjustment as provided
in Section 4(b), no Participant may receive Options under the Plan in any
calendar year that relate to more than 500,000 Shares; provided, however, a
Participant may receive Options that relate to up to 1,000,000 Shares during the
initial year of the Plan or in the calendar year in which the Participant's
employment with the Company begins.

     (b) Adjustments. In the event that the Committee determines that any
dividend or other distribution (whether in the form of cash, Shares, other
securities, or other property), recapitalization, stock split, reverse stock
split, reorganization, merger, consolidation, split-up, spin-off, combination,
repurchase, exchange of Shares or other securities of the Company, issuance of
warrants or other rights to purchase Shares or other securities of the Company,
or other similar corporate transaction or event affects the Shares such that an
adjustment is determined by the Committee to be appropriate in order to prevent
dilution or enlargement of the benefits or potential benefits intended to be
made available under the Plan, then the Committee shall, in such manner as it
may deem equitable: (i) adjust any or all of (1) the number of Shares or other
securities of the Company (or number and kind of other securities or property)
with respect to which Awards may be granted, (2) the maximum number of Shares
subject to Awards granted to a Participant pursuant to Sections 4(a) and 11(b)
of the Plan, (3) the number of Shares or other securities of the Company (or
number and kind of other securities or property) subject to outstanding Awards
and (4) the grant or exercise price with respect to any Award; (ii) if deemed
appropriate, provide for an equivalent award in respect of securities of the
surviving entity of any merger, consolidation or other transaction or event
having a similar effect; or (iii) if deemed appropriate, make provision for a
cash payment to the holder of an outstanding Award; provided, in each case, that
(A) with respect to Awards of Incentive Stock Options no such adjustment shall
be authorized to the extent that such authority would cause the Plan to violate
Section 422(b)(1) of the Code, as from time to time amended and (B) with respect
to any Award no such adjustment shall be authorized to the extent that such
authority would be inconsistent with the Plan's meeting the requirements of
Section 162(m), unless otherwise determined by the Committee.

     (c) Substitute Awards. Any Shares underlying Substitute Awards shall not,
unless required by Section 16, be counted against the Shares available for
Awards under the Plan.

     (d) Sources of Shares Deliverable Under Awards. Any Shares delivered
pursuant to an Award may consist, in whole or in part, of authorized and
unissued Shares or of treasury Shares.

                                       4

SECTION 5.

     ELIGIBILITY. Any Employee (including any officer or employee-director of
the Company or any Affiliate who is not a member of the Committee), Non-Employee
Director or consultant shall be eligible to be designated a Participant;
provided that Non-Employee Directors shall only be eligible to receive Awards
granted pursuant to Section 10.

SECTION 6.

STOCK OPTIONS.

     (a) Grant. Subject to the provisions of the Plan, the Committee shall have
sole and complete authority to determine the Participants to whom Options shall
be granted, the number of Shares to be covered by each Option, the option price
and the conditions and limitations applicable to the exercise of the Option. The
Committee shall have the authority to grant Incentive Stock Options, or to grant
NonQualified Stock Options, or to grant both types of options. In the case of
Incentive Stock Options, the terms and conditions of such grants shall be
subject to and comply with such rules as may be prescribed by Section 422 of the
Code, as from time to time amended, and any regulations implementing such
statute.

     (b) Exercise Price. The Committee in its sole discretion shall establish
the exercise price at the time each Option is granted. Except in the case of
Substitute Awards, the exercise price of an Option may not be less than the Fair
Market Value on the date of grant of such Option.

     (c) Exercise. Each Option shall be exercisable at such times and subject to
such terms and conditions as the Committee may, in its sole discretion, specify
in the applicable Award Agreement or thereafter. The Committee may impose such
conditions with respect to the exercise of options, including without
limitation, any relating to the application of federal, state or foreign
securities laws or the Code, as it may deem necessary or advisable.
Notwithstanding the foregoing, an Option shall not be exercisable after the
expiration of ten years from the date such Option was granted.

     (d) Payment. No Shares shall be delivered pursuant to any exercise of an
Option until payment in full of the option price is received by the Company.
Such payment may be made in cash, or its equivalent, or by exchanging Shares
owned by the Participant for at least six months (which are not the subject of
any pledge or other security interest), or by a combination of the foregoing,
provided that the combined value of all cash and cash equivalents and the Fair
Market Value of any such Shares so tendered to the Company as of the date of
such tender is at least equal to such option price. A Participant may elect to
pay all or any portion of the aggregate exercise price by having Shares with a
Fair Market Value on the date of exercise equal to the aggregate exercise price
withheld by the Company or sold by a broker-dealer.

SECTION 7.

RESTRICTED STOCK AND RESTRICTED STOCK UNITS.

     (a) Grant. Subject to the provisions of the Plan, the Committee shall have
sole and complete authority to determine the Participants to whom Shares of
Restricted Stock and Restricted Stock Units shall be granted, the number of
Shares of Restricted Stock and/or the number of Restricted Stock Units to be
granted to each Participant, the duration of the period during which, and the
conditions under which, the Restricted Stock and Restricted Stock Units may be
forfeited to the Company, and the other terms and conditions of such Awards.

     (b) Transfer Restrictions. Shares of Restricted Stock and Restricted Stock
Units may not be sold, assigned, transferred, pledged or otherwise encumbered,
except, in the case of Restricted Stock, as provided in the Plan or the
applicable Award Agreements. Certificates issued in respect of Shares of
Restricted Stock shall be registered in the name of the Participant and
deposited by such Participant, together with a stock power endorsed in blank,
with the Company. Upon the lapse of the restrictions applicable to such Shares
of Restricted Stock, the Company shall deliver such certificates to the
Participant or the Participant's legal representative.

     (c) Payment. Each Restricted Stock Unit shall have a value equal to the
Fair Market Value of a Share. Restricted Stock Units shall be paid in cash,
Shares, other securities or other property, as determined in the sole discretion
of the Committee, upon the lapse of the restrictions applicable thereto, or
otherwise in accordance with the applicable Award Agreement.

                                       5

     (d) Dividends and Distributions. Dividends and other distributions paid on
or in respect of Restricted Stock or Restricted Stock Units may be paid directly
to the Participant, or may be reinvested in additional Shares of Restricted
Stock or in additional Restricted Stock Units, as determined by the Committee in
its sole discretion.

SECTION 8.

PERFORMANCE AWARDS.

     (a) Grant. The Committee shall have sole and complete authority to
determine the Participants who shall receive a "Performance Award," which shall
consist of a right that is (i) denominated in cash or Shares, (ii) valued, as
determined by the Committee, in accordance with the achievement of such
performance goals during such performance periods as the Committee shall
establish, and (iii) payable at such time and in such form as the Committee
shall determine.

     (b) Terms and Conditions. Subject to the terms of the Plan and any
applicable Award Agreement, the Committee shall determine the performance goals
to be achieved during any performance period, the length of any performance
period, the amount of any Performance Award and the amount and kind of any
payment or transfer to be made pursuant to any Performance Award.

     (c) Payment of Performance Awards. Performance Awards may be paid in a lump
sum or in installments following the close of the performance period or, in
accordance with procedures established by the Committee, on a deferred basis.

SECTION 9.

     OTHER STOCK-BASED AWARDS. The Committee shall have authority to grant to
Participants an "Other Stock-Based Award," which shall consist of any right that
is (i) not an Award described in Sections 6 through 8 above and (ii) an Award of
Shares or an Award denominated or payable in, valued in whole or in part by
reference to, or otherwise based on or related to, Shares (including, without
limitation, securities convertible into Shares), as deemed by the Committee to
be consistent with the purposes of the Plan. Subject to the terms of the Plan
and any applicable Award Agreement, the Committee shall determine the terms and
conditions of any such Other Stock-Based Award.

SECTION 10.

     NON-EMPLOYEE DIRECTOR AWARDS. The Committee may provide that all or a
portion of a Non-Employee Director's annual retainer and/or meeting fees be
payable (either automatically or at the election of a Non-Employee Director) in
the form of Nonqualified Stock Options, Restricted Stock and/or Other
Stock-Based Awards, including unrestricted Shares. Subject to the terms of the
Plan and any applicable Award Agreement, the Committee shall determine the terms
and conditions of any such Awards. In addition, the Committee may, in its sole
discretion, grant awards of Restricted Stock to Non-Employee Directors pursuant
to such terms and conditions as it may deem advisable, so long as such terms and
conditions are not inconsistent with any other terms of the Plan.

                                       6

SECTION 11.

PROVISIONS APPLICABLE TO COVERED OFFICERS AND PERFORMANCE-BASED AWARDS.

     Notwithstanding anything in the Plan to the contrary, unless the Committee
determines otherwise, all performance-based Restricted Stock Awards, Restricted
Stock Units, Performance Awards, or other Stock-Based Awards shall be subject to
the terms and provisions of this Section 11.

     (a) The Committee may grant Restricted Stock Awards, Restricted Stock
Units, Performance Awards and Other Stock-Based Awards to Covered Officers that
vest or become exercisable upon the attainment of performance targets related to
one or more performance goals selected by the Committee from among the goals
specified below. For the purposes of this Section 11, performance goals shall be
limited to one or more of the following Company, subsidiary, operating unit or
division financial performance measures:

               (i)       earnings before interest, taxes, depreciation and/or
                         amortization
               (ii)      operating income or profit
               (iii)     return on equity, assets, capital, capital employed, or
                         investment
               (iv)      after tax operating income
               (v)       net income
               (vi)      earnings or book value per share
               (vii)     cash flow(s)
               (viii)    total sales or revenues or sales or revenues per
                         employee
               (ix)      production (separative work units or SWUs)
               (x)       stock price or total shareholder return
               (xi)      dividends
               (xii)     strategic business objectives, consisting of one or
                         more objectives based on meeting specified cost
                         targets, business expansion goals, and goals relating
                         to acquisitions or divestitures
               (xiii)    except in the case of Section 162(m) awards to Covered
                         Officers, any other performance criteria established by
                         the Committee

or any combination thereof. Each goal may be expressed on an absolute and/or
relative basis, may be based on or otherwise employ comparisons based on
internal targets, the past performance of the Company and/or the past or current
performance of other companies, and in the case of earnings-based measures, may
use or employ comparisons relating to capital, shareholders' equity and/or
shares outstanding, or to assets or net assets.

     (b) With respect to any Participant, the maximum annual number of shares in
respect of which Restricted Stock Awards, Performance Awards and Other
Stock-Based Awards may be granted under the Plan is 200,000 and the maximum
annual amount of any Award settled in cash is $2,000,000.

     (c) To the extent necessary to comply with Section 162(m), with respect to
Restricted Stock Awards, Restricted Stock Units, Performance Awards and Other
Stock-Based Awards, no later than 90 days following the commencement of each
performance period (or such other time as may be required or permitted by
Section 162(m) of the Code), the Committee shall, in writing, (A) select the
performance goal or goals applicable to the performance period, (B) establish
the various targets and bonus amounts which may be earned for such performance
period and (C) specify the relationship between performance goals and targets
and the amounts to be earned by each Covered Officer for such performance
period. Following the completion of each performance period, the Committee shall
certify in writing whether the applicable performance targets have been achieved
and the amounts, if any, payable to Covered Officers for such performance
period. In determining the amount earned by a Covered Officer for a given
performance period, subject to any applicable Award Agreement, the Committee
shall have the right to reduce (but not increase) the amount payable at a given
level of performance to take into account additional factors that the Committee
may deem relevant to the assessment of individual or corporate performance for
the performance period.

                                       7

SECTION 12.

     TERMINATION OF EMPLOYMENT/SERVICE. The Committee shall have the full power
and authority to determine the terms and conditions that shall apply to any
Award upon a termination of employment/service, including a termination by the
Company without Cause, by a Participant voluntarily, or by reason of death,
Disability or Retirement.

SECTION 13.

     CHANGE IN CONTROL. Upon a Change in Control, all outstanding Awards shall
vest, become immediately exercisable or payable or have all restrictions lifted.

SECTION 14.

AMENDMENT AND TERMINATION.

     (a) Amendments to the Plan. The Board may amend, alter, suspend,
discontinue, or terminate the Plan or any portion thereof at any time; provided
that no such amendment, alteration, suspension, discontinuation or termination
shall be made without shareholder approval if such approval is necessary to
comply with any tax or regulatory requirement for which or with which the Board
deems it necessary or desirable to comply.

     (b) Amendments to Awards. The Committee may waive any conditions or rights
under, amend any terms of, or alter, suspend, discontinue, cancel or terminate,
any Award theretofore granted, prospectively or retroactively; provided that any
such waiver, amendment, alteration, suspension, discontinuance, cancellation or
termination that would adversely affect the rights of any Participant or any
holder or beneficiary of any Award theretofore granted shall not to that extent
be effective without the consent of the affected Participant, holder, or
beneficiary; and provided further that the Committee shall not have the power to
amend the terms of previously granted Awards to reduce, or cancel such Awards
and grant substitute Awards which would have the effect of reducing the exercise
price except pursuant to paragraph (c) below.

     (c) Adjustment of Awards Upon the Occurrence of Certain Unusual or
Nonrecurring Events. The Committee is hereby authorized to make adjustments in
the terms and conditions of, and the criteria included in, Awards in recognition
of unusual or nonrecurring events (including, without limitation, the events
described in Section 4(b) hereof) affecting the Company, any Affiliate, or the
financial statements of the Company or any Affiliate, or of changes in
applicable laws, regulations, or accounting principles, whenever the Committee
determines that such adjustments are appropriate in order to prevent dilution or
enlargement of the benefits or potential benefits intended to be made available
under the Plan; provided that no such adjustment shall be authorized to the
extent that such authority would be inconsistent with the Plan's meeting the
requirements of Section 162(m), unless otherwise determined by the Committee.

SECTION 15.

GENERAL PROVISIONS.

     (a) Dividend Equivalents. In the sole and complete discretion of the
Committee, an Award may provide the Participant with dividends or dividend
equivalents, payable in cash, Shares, other securities or other property on a
current or deferred basis.

     (b) Transferability. Except as provided below, no Award shall be assigned,
alienated, pledged, attached, sold or otherwise transferred or encumbered by a
Participant, except by will or the laws of descent and distribution.
Notwithstanding the foregoing, a Participant may transfer any vested Award,
other than an Incentive Stock Option, to members of his or her immediate family
(defined as his or her spouse, children or grandchildren) or to one or more
trusts for the exclusive benefit of such immediate family members or
partnerships in which such immediate family members are the only partners if the
Award Agreement so provides, the transfer is approved by the Committee and the
Participant does not receive any consideration for the transfer. Any such
transferred Award shall continue to be subject to the same terms and conditions
that were applicable to such Award immediately prior to its transfer (except
that such transferred Award shall not be further transferable by the
transferee).

     (c) No Rights to Awards. No Person shall have any claim to be granted any
Award, and there is no obligation for uniformity of treatment of Employees,

                                       8

Non-Employee Directors, consultants, Participants, or holders or beneficiaries
of Awards. The terms and conditions of Awards need not be the same with respect
to each recipient.

     (d) Share Certificates. All certificates for Shares or other securities of
the Company or any Affiliate delivered under the Plan pursuant to any Award or
the exercise thereof shall be subject to such stop transfer orders and other
restrictions as the Committee may deem advisable under the Plan or the rules,
regulations, and other requirements of the SEC, any stock exchange upon which
such Shares or other securities are then listed, and any applicable Federal or
state laws, and the Committee may cause a legend or legends to be put on any
such certificates to make appropriate reference to such restrictions.

     (e) Withholding. A participant may be required to pay to the Company or any
Affiliate and the Company or any Affiliate shall have the right and is hereby
authorized to withhold from any Award, from any payment due or transfer made
under any Award or under the Plan or from any compensation or other amount owing
to a Participant the amount (in cash, Shares, other securities, other Awards or
other property) of any applicable withholding or other taxes in respect of an
Award, its exercise, or any payment or transfer under an Award or under the Plan
and to take such other action as may be necessary in the opinion of the Company
to satisfy all obligations for the payment of such taxes. The Committee may
provide for additional cash payments to holders of Awards to defray or offset
any tax arising from the grant, vesting, exercise, or payments of any Award.

     (f) Award Agreements. Each Award hereunder shall be evidenced by an Award
Agreement that shall be delivered to the Participant and shall specify the terms
and conditions of the Award and any rules applicable thereto. In the event of a
conflict between the terms of the Plan and any Award Agreement, the terms of the
Award Agreement shall prevail.

     (g) No Limit on Other Compensation Arrangements. Nothing contained in the
Plan shall prevent the Company or any Affiliate from adopting or continuing in
effect other compensation arrangements, which may, but need not, provide for the
grant of options, restricted stock, Shares and other types of Awards provided
for hereunder (subject to shareholder approval if such approval is required),
and such arrangements may be either generally applicable or applicable only in
specific cases.

     (h) No Right to Employment. The grant of an Award shall not be construed as
giving a Participant the right to be retained in the employ of the Company or
any Affiliate. Further, the Company or an Affiliate may at any time dismiss a
Participant from employment, free from any liability or any claim under the
Plan, unless otherwise expressly provided in the Plan or in any Award Agreement.

     (i) No Rights as Shareholder. Subject to the provisions of the applicable
Award, no Participant or holder or beneficiary of any Award shall have any
rights as a shareholder with respect to any Shares to be distributed under the
Plan until he or she has become the holder of such Shares. Notwithstanding the
foregoing, in connection with each grant of Restricted Stock hereunder, the
applicable Award shall specify if and to what extent the Participant shall not
be entitled to the rights of a shareholder in respect of such Restricted Stock.

     (j) Governing Law. The validity, construction, and effect of the Plan and
any rules and regulations relating to the Plan and any Award Agreement shall be
determined in accordance with the laws of the State of Delaware without giving
effect to the conflict of law principles thereof.

     (k) Severability. If any provision of the Plan or any Award is or becomes
or is deemed to be invalid, illegal, or unenforceable in any jurisdiction or as
to any Person or Award, or would disqualify the Plan or any Award under any law
deemed applicable by the Committee, such provision shall be construed or deemed
amended to conform to the applicable laws, or if it cannot be construed or
deemed amended without, in the determination of the Committee, materially
altering the intent of the Plan or the Award, such provision shall be stricken
as to such jurisdiction, Person or Award and the remainder of the Plan and any
such Award shall remain in full force and effect.

     (l) Other Laws. The Committee may refuse to issue or transfer any Shares or
other consideration under an Award if, acting in its sole discretion, it
determines that the issuance or transfer of such Shares or such other
consideration might violate any applicable law or regulation (including
applicable non-U.S. laws or regulations) or entitle the Company to recover the
same under Section 16(b), and any payment tendered to the Company by a
Participant, other holder or beneficiary in connection with the exercise of such
Award shall be promptly refunded to the relevant Participant, holder, or
beneficiary. Without limiting the generality of the foregoing, no Award granted
hereunder shall be construed as an offer to sell securities of the Company, and
no such offer shall be outstanding, unless and until the Committee in its sole
discretion has determined that any such offer, if made, would be in compliance
with all applicable requirements of the U.S. federal or non-U.S. securities laws
and any other laws to which such offer, if made, would be subject.

                                       9

     (m) No Trust or Fund Created. Neither the Plan nor any Award shall create
or be construed to create a trust or separate fund of any kind or a fiduciary
relationship between the Company or any Affiliate and a Participant or any other
Person. To the extent that any Person acquires a right to receive payments from
the Company or any Affiliate pursuant to an Award, such right shall be no
greater than the right of any unsecured general creditor of the Company or any
Affiliate.

     (n) No Fractional Shares. No fractional Shares shall be issued or delivered
pursuant to the Plan or any Award, and the Committee shall determine whether
cash, other securities, or other property shall be paid or transferred in lieu
of any fractional Shares or whether such fractional Shares or any rights thereto
shall be canceled, terminated or otherwise eliminated.

     (o) Headings. Headings are given to the Sections and subsections of the
Plan solely as a convenience to facilitate reference. Such headings shall not be
deemed in any way material or relevant to the construction or interpretation of
the Plan or any provision thereof.

SECTION 16.

TERM OF THE PLAN.

     (a) Effective Date. The Plan shall be effective as of February 2, 1999,
provided it has been approved by the Company's shareholders.

     (b) Expiration Date. No new Awards shall be granted under the Plan after
the tenth anniversary of the Effective Date. Unless otherwise expressly provided
in the Plan or in an applicable Award Agreement, any Award granted hereunder
may, and the authority of the Board or the Committee to amend, alter, adjust,
suspend, discontinue, or terminate any such Award or to waive any conditions or
rights under any such Award shall, continue after the authority for grant of new
Awards hereunder has been exhausted.

                                       10

                                                                     Exhibit 4.2

                   USEC Inc. 1999 EMPLOYEE STOCK PURCHASE PLAN

SECTION 1.

     PURPOSE. The purpose of the USEC Inc. 1999 Employee Stock Purchase Plan
(the "Plan") is to provide employees of USEC Inc. (the "Company") and its
subsidiaries with an opportunity to become part owners of the Company by
purchasing Shares (as defined below) through annual offerings financed by
payroll deductions and/or lump sum payment contributions. It is the intention of
the Company to have the Plan qualify as an "Employee Stock Purchase Plan" under
Section 423 of Code (as defined below). The provisions of the Plan shall be
construed accordingly.

SECTION 2.

     DEFINITIONS. As used in the Plan, the following terms shall have the
meanings set forth below:

          "Affiliate" shall mean (i) any entity that, directly or indirectly, is
     controlled by the Company, (ii) any entity in which the Company has a
     significant equity interest and (iii) an affiliate of the Company, as
     defined in Rule 12b-2 promulgated under Section 12 of the Exchange Act, in
     each case as determined by the Committee.

          "Board" shall mean the Board of Directors of the Company.

          "Code" shall mean the Internal Revenue Code of 1986, as amended from
     time to time.

          "Change in Control" shall mean, unless otherwise defined in an
     Agreement, a change in control of the Company, which will be deemed to have
     occurred if:

          (i) any "Person," as such term is used in Sections 13(d) and 14(d) of
     the Exchange Act (other than (A) the Company, (B) any trustee or other
     fiduciary holding securities under an employee benefit plan of the Company,
     and (C) any corporation owned, directly or indirectly, by the shareholders
     of the Company in substantially the same proportions as their ownership of
     Shares), is or becomes the "beneficial owner" (as defined in Rule 13d-3
     under the Exchange Act), directly or indirectly, of securities of the
     Company (not including any securities acquired directly from the Company or
     its Affiliates) representing 25% or more of the combined voting power of
     the Company's then outstanding voting securities;

          (ii) the following individuals cease for any reason to constitute a
     majority of the number of directors then serving: individuals who, on the
     effective date (as defined in Section 12(a) of the Plan), constitute the
     Board and any new director (other than a director whose initial assumption
     of office is in connection with an actual or threatened election contest,
     including but not limited to a consent solicitation, relating to the
     election of directors of the Company) whose appointment or election by the
     Board or nomination for election by the Company's shareholders was approved
     or recommended by a vote of at least two-thirds (2/3) of the directors then
     still in office who either were directors on the effective date of the Plan
     or whose appointment, election or nomination for election was previously so
     approved or recommended;

          (iii) there is consummated a merger or consolidation of the Company or
     any direct or indirect subsidiary of the Company with any other
     corporation, other than (A) a merger or consolidation that would result in
     the voting securities of the Company outstanding immediately prior thereto
     continuing to represent (either by remaining outstanding or by being
     converted into voting securities of the surviving or parent entity) more
     than 60% of the combined voting power of the voting securities of the
     Company or such surviving or parent entity outstanding immediately after
     such merger or consolidation or (B) a merger or consolidation effected to
     implement a recapitalization of the Company (or similar transaction) in
     which no "person" (as defined above), directly or indirectly, acquired 40%
     or more of the combined voting power of the Company's then outstanding
     securities (not including any securities acquired directly from the Company
     or its Affiliates); or

          (iv) the shareholders of the Company approve a plan of complete
     liquidation of the Company or there is consummated an agreement for the
     sale or disposition by the Company of all or substantially all of the

     Company's assets (or any transaction having a similar effect), other than a
     sale or disposition by the Company of all or substantially all of the
     Company's assets to an entity, at least 60% of the combined voting power of
     the voting securities of which are owned by shareholders of the Company in
     substantially the same proportions as their ownership of the Company
     immediately prior to such sale.

          "Committee" shall mean a committee of the Board designated by the
     Board to administer the Plan.

          "Compensation" shall mean the total earnings, prior to withholding,
     paid to an Employee during the applicable pay period, including overtime
     and bonus payments. Compensation shall exclude relocation expenses, tax
     gross ups, referral bonuses, tuition reimbursement, the imputed value of
     group life insurance, car allowances, contest earnings, any employer
     contributions to a 401(k) plan, or other similar extraordinary remuneration
     received by such Employee.

          "Employee" shall mean any individual who is an employee of the Company
     or of any Subsidiary whose customary employment with the Company is at
     least twenty (20) hours per week or five (5) months in any calendar year
     (within the meaning of Sections 423(b)(4) (B) and (C) of the Code,
     respectively). For purposes of the Plan, the employment relationship shall
     be treated as continuing intact while the individual is on sick leave or
     other leave of absence approved by the Company. Where the period of leave
     exceeds 90 days and the Employee's right to reemployment is not guaranteed
     either by statute or by contract, the employment relationship shall be
     deemed to have terminated on the 91st day of such leave.

          "Enrollment Date" shall mean the first day of each Offering Period.

          "Exchange Act" shall mean the Securities Exchange Act of 1934, as
     amended.

          "Fair Market Value" with respect to the Shares, as of any date, shall
     mean (i) the closing sales price of the Shares on the New York Stock
     Exchange or any other such exchange on which the Shares are traded, or in
     the absence of reported sales on such date, the closing sales price on the
     immediately preceding date on which sales were reported, (ii) in the event
     there is no public market for the Shares, the fair market value as
     determined, in good faith, by the Committee in its sole discretion.

          "Offering Period" shall mean a period of approximately six (6) months,
     or such other period (not to exceed one year) as determined by the
     Committee.

          "Participant" shall mean an Employee who elects to participate in the
     Plan by filing an Enrollment Form (as defined in Section 6(b) hereof).

          "Person" shall mean any individual, corporation, partnership,
     association, joint-stock company, trust, unincorporated organization,
     government or political subdivision thereof or other entity.

          "Purchase Date" shall mean the date the Plan administrator shall
     acquire Shares for Participants (which shall be the last day of the
     Offering Period, unless otherwise determined by the Committee).

          "SEC" shall mean the Securities and Exchange Commission or any
     successor thereto and shall include the staff thereof.

          "Shares" shall mean shares of the common stock, $0.10 par value, of
     the Company, or such other securities of the Company as may be designated
     by the Committee from time to time.

          "Subsidiary" shall mean a subsidiary of the Company as defined under
     Section 424(f) of the Code.

                                        2

SECTION 3.

ADMINISTRATION.

     (a) Authority of Committee. The Plan shall be administered by the
Committee. Subject to the express provisions of the Plan and applicable law, and
in addition to other express powers and authorizations conferred on the
Committee by the Plan, the Committee shall have full power and authority to
construe and interpret the Plan and may from time to time adopt such rules and
regulations for carrying out the Plan as it may deem necessary or desirable for
the administration of the Plan, including, but not limited to, the determination
of Offering Periods hereunder.

     (b) Committee Discretion Binding. Unless otherwise expressly provided in
the Plan, all designations, determinations, interpretations, and other decisions
under or with respect to the Plan, shall be within the sole discretion of the
Committee, may be made at any time and shall be final, conclusive, and binding
upon all Persons, including the Company, any Subsidiary, any Participant, any
Employee, and any designated beneficiary.

     (c) Delegation. Subject to the terms of the Plan and applicable law, the
Committee may delegate to one or more officers or managers of the Company or any
Subsidiary, or to a committee of such officers or managers, the authority,
subject to such terms and limitations as the Committee shall determine, to
administer the Plan.

     (d) No Liability. No member of the Board or Committee shall be liable for
any action taken or determination made in good faith with respect to the Plan.

     (e) Agreements. The Committee may in its sole discretion determine from
time to time that the Company shall offer to enter into agreements hereunder
("Agreements") with all of the Participants, provided, however, that it shall be
under no obligation to do so.

SECTION 4.

SHARES AVAILABLE FOR AWARDS.

     (a) Shares Available. Subject to adjustment as provided in Section 4(b),
the number of Shares which may be sold under the Plan shall not exceed 2,500,000
shares. In the event that any Shares offered during an Offering Period are not
purchased, such unpurchased Shares may again be sold under the Plan.

     (b) Adjustments. In the event that the Committee determines that any
dividend or other distribution (whether in the form of cash, Shares, other
securities, or other property), recapitalization, stock split, reverse stock
split, reorganization, merger, consolidation, split-up, spin-off, combination,
repurchase, or exchange of Shares or other securities of the Company, issuance
of warrants or other rights to purchase Shares or other securities of the
Company, or other similar corporate transaction or event affects the Shares such
that an adjustment is determined by the Committee to be appropriate in order to
prevent dilution or enlargement of the benefits or potential benefits intended
to be made available under the Plan, then the Committee shall, in such manner as
it may deem appropriate make such equitable adjustments in the Plan and the then
outstanding offerings as it deems necessary and appropriate, including but not
limited to changing the number of Shares reserved under the Plan and the price
of the current offering.

     (c) Source of Shares. Shares which are to be delivered under the Plan may
be obtained by the Company from its treasury, by purchases on the open market or
from private sources, or by issuing authorized but unissued Shares. Any issuance
of authorized but unissued Shares shall be approved by the Board or the
Committee. Authorized but unissued Shares may not be delivered under the Plan if
the purchase price thereof is less than the par value of the Shares. Subject to
the provisions of Section 11(i) below, fractional Shares may not be issued and
sold under the Plan.

     (d) Oversubscription. If the number of Shares that Participants become
entitled to purchase is greater than the number of Shares offered in a
particular Offering Period or remaining available, the available Shares shall be
allocated by the Committee among such Participants in such manner as it deems
fair and equitable.

                                        3

SECTION 5.

     ELIGIBILITY. All Employees (including Employees who are directors) of the
Company or of any Subsidiary designated by the Committee, will be eligible to
participate in the Plan, in accordance with such rules as may be prescribed from
time to time; provided, however, that such rules shall neither permit nor deny
participation in the Plan contrary to the requirements of the Code (including,
but not limited to, Sections 423(b)(3), (4) and (5) thereof) and regulations
promulgated thereunder. No Employee shall be eligible to participate in the Plan
until the completion of six (6) months of service. During an Offering Period, no
Employee may participate under the Plan if such Employee would own 5% or more of
the total combined voting power or value of all classes of stock of the Company
or any Subsidiary. For purposes of the preceding sentence, the rules of Section
424(d) of the Code shall apply in determining the stock ownership of an
Employee, and Shares which the Employee would be permitted to purchase under the
current Offering Period shall be treated as Shares owned by the Employee.

SECTION 6.

PARTICIPATION AND OFFERINGS.

     (a) The Company may authorize one or more Offering Periods to Employees to
purchase Shares under the Plan. The Committee may at any time suspend an
Offering Period if required by law or if the Committee determines in good faith
that it is in the best interests of the Company.

     (b) Eligible Employees may become Participants in such Offering Periods at
such time(s) as determined by the Committee by filing a form of enrollment
("Enrollment Form") with the Company authorizing specified regular payroll
deductions or lump-sum payments. Subject to paragraph (c) below, payroll
deductions for such purpose shall be in one percent (1%) increments of
Compensation subject to a minimum of one percent (1%) and a maximum deduction of
ten percent (10%) of Compensation per pay period. Notwithstanding the foregoing,
in no event may the sum of a Participant's lump sum contributions and payroll
deductions exceed 10% of a participant's Compensation for the applicable
Offering Period.

     (c) Notwithstanding anything else contained herein, no Employee may
purchase Shares under this Plan and any other qualified employee stock purchase
plan (within the meaning of Section 423 of the Code) of the Company or its
Subsidiaries at a rate which exceeds $25,000 of Fair Market Value of Shares for
each calendar year in which a purchase is executed. For purposes of this
Section, Fair Market Value shall be determined as of the first date of the
applicable Offering Period.

     (d) The Company and participating Subsidiaries will establish Participant
recordkeeping accounts authorizing a payroll deduction pursuant to Section 6(b).

     (e) A Participant may, by written notice at any time during the Offering
Period, direct the Company to reduce or increase payroll deductions (or, if the
payment for Shares is being made through periodic lump sum payments, notify the
Company that such payments will be increased, reduced, or terminated), subject
to a maximum of one change per Offering Period.

     (f) A Participant may elect to withdraw all of his or her entire account
prior to the end of the Offering Period. No partial withdrawal will be permitted
unless otherwise determined by the Committee. Any such withdrawal will terminate
such Participant's participation for the remainder of the Offering Period. If a
Participant withdraws from an Offering Period, payroll deductions shall not
resume at the beginning of the succeeding Offering Period unless the participant
delivers to the Company a new Enrollment Form.

     (g) As of the last day of the Offering Period, the recordkeeping account of
each Participant shall be totaled. Subject to the provisions of Section 6(f)
above, if such account contains sufficient funds to purchase one or more Shares
as of that date, the employee shall be deemed to have purchased the largest
number of Shares at the price determined under Section 7 below; such
Participant's account will be charged, on that date, for the amount of the
purchase, and for all purposes under the Plan the Participant shall be deemed to
have acquired the Shares on that date. The registrar for the Company will make
an entry on its books and records evidencing that such Shares have been duly
issued as of that date; provided, however, that a Participant may, in the
alternative, elect in writing prior thereto to receive a stock certificate
representing the amount of such full Shares acquired (and any remaining balance
shall be returned to such Participant by check or remain in the recordkeeping
account for the succeeding Offering Period).

     (h) Each Participant may be requested to notify the Company of any
disposition of Shares purchased pursuant to the Plan prior to the expiration of
the holding periods set forth in Section 423(a) of the Code.

                                        4

SECTION 7.

     PURCHASE PRICE. The purchase price of a Share pursuant to a transaction
under the Plan shall be the lesser of: (a) 85% of the Fair Market Value of a
Share on the Enrollment Date of the applicable Offering Period, and (b) 85% of
the Fair Market Value of a Share on the Purchase Date of the applicable Offering
Period.

SECTION 8

     TERMINATION OF EMPLOYMENT. Unless otherwise specified in an Agreement, upon
a Participant's ceasing to be an Employee of the Company or a participating
Subsidiary, for any reason, he or she shall be deemed to have elected to
withdraw from the Plan and the payroll deductions credited to such Participant's
account during the Offering Period, but not yet used, shall be returned to the
Participant or, in the case of his or her death, to the Participant's designated
beneficiary or estate.

SECTION 9.

     TRANSFERABILITY. Neither payroll deductions credited to a Participant's
account nor any rights with regard to the purchase of Shares under the Plan may
be assigned, transferred, pledged, or otherwise disposed of in any way (other
than by will, laws of descent and distribution, or beneficiary designation) by a
Participant. Any such attempt at assignment, transfer, pledge, or other
disposition shall be without effect, except that the Company may treat such act
as an election to withdraw funds from an Offering Period in accordance with
Section 6(f) hereof.

SECTION 10.

     CHANGE IN CONTROL. Unless otherwise specified in an Agreement,
notwithstanding anything in the Plan to the contrary, in the event of a Change
in Control of the Company, if the Committee determines that the operation or
administration of the Plan could prevent Participants from obtaining the benefit
of accrued purchase rights under the Plan, the Plan may be terminated in any
manner deemed by the Committee to provide equitable treatment to Participants.
Equitable treatment may include, but is not limited to, payment to each
Participant of the amount of contributions and interest standing to such
Participant's account as of the date of the Change in Control, plus an
additional amount determined by (A) calculating the number of full Shares that
could have been purchased for the Participant immediately prior to the Change in
Control at the purchase price (determined under Section 7 at the beginning of
the Offering Period (the "Purchase Price")) and (B) multiplying that number of
Shares by the difference between the Purchase Price per Share and the highest
price paid per Share in connection with the Change in Control of the Company.

SECTION 11.

GENERAL PROVISIONS.

     (a) Amendments. The Board may, from time to time, alter, amend, suspend, or
discontinue the Plan or alter or amend any and all Agreements; provided,
however, that no such action of the Board may, without the approval of the
shareholders, make any amendment for which shareholder approval is necessary to
comply with any tax or regulatory requirement, including for this purpose, any
approval requirement which is a prerequisite for exemptive relief under Section
16(b) of the Exchange Act or Sections 423 and 424 of the Code.

     (b) No Right to Employment. The grant of an Award shall not be construed as
giving a Participant the right to be retained in the employment of the Company
or any Subsidiary. Further, the Company or any Subsidiary may at any time
dismiss a Participant from employment, free from any liability or any claim
under the Plan, unless otherwise expressly provided in the Plan.

     (c) No Rights as Shareholder. Subject to the provisions of the Plan, no
Participant or holder or beneficiary of any purchase shall have any rights as a
shareholder with respect to any Shares to be distributed under the Plan until
such Shares have been purchased pursuant to Section 6(g) hereof.

     (d) Obligatory Status. Participation in the Plan shall impose no obligation
upon a Participant to purchase any Shares under the Plan.

     (e) Application of Funds. The proceeds received by the Company from the
sale of Shares pursuant to purchases under the Plan will be used for general
corporate purposes.

                                        5

     (f) Severability. If any provision of the Plan becomes or is deemed to be
invalid, illegal, or unenforceable in any jurisdiction or as to any person, or
would disqualify the Plan or any purchase under any law deemed applicable by the
Committee, such provision shall be construed or deemed amended to conform to the
applicable laws, or if it cannot be construed or deemed amended without, in the
determination of the Committee, materially altering the intent of the Plan, such
provision shall be stricken as to such jurisdiction or person, and the remainder
of the Plan shall remain in full force and effect.

     (g) Governing Law. The validity, construction, and effect of the Plan and
any rules and regulations relating to the Plan shall be determined in accordance
with the laws of the State of Delaware, without giving effect to the conflict of
law principles thereof.

     (h) Other Laws. The Committee may refuse to issue or transfer any Shares
if, acting in its sole discretion, it determines that the issuance or transfer
of such Shares or such other consideration might violate any applicable law or
regulation (including applicable non-U.S. laws or regulations) or entitle the
Company to recover the same under Section 16(b) of the Exchange Act, and any
payment tendered to the Company by a Participant, other holder or beneficiary in
connection with the purchase of such Shares shall be promptly refunded to the
relevant Participant, holder, or beneficiary. Without limiting the generality of
the foregoing, no Plan provision shall be construed as an offer to sell
securities of the Company, and no such offer shall be outstanding, unless and
until the Committee in its sole discretion has determined that any such offer,
if made, would be in compliance with all applicable requirements of the U.S.
federal or non-U.S. securities laws and any other laws to which such offer, if
made, would be subject.

     (i) No Fractional Shares. No fractional Shares shall be issued or delivered
pursuant to the Plan. Any payroll deductions or lump sum contributions credited
to a Participant's account which are not sufficient to purchase a full share
shall be retained in the Participant's recordkeeping account for the subsequent
Offering Period, subject to early withdrawal by the Participant as provided in
Section 6(f) hereof, or distributed as a cash payment on the Purchase Date.

     (j) Shareholder Approval. This Plan shall not be effective until approved
by the shareholders of the Company as provided in Section 423(b)(2) of the Code
and the regulations thereunder.

     (k) Headings. Headings are given to the Sections and subsections of the
Plan solely as a convenience to facilitate reference. Such headings shall not be
deemed in any way material or relevant to the construction or interpretation of
the Plan or any provision thereof.

SECTION 12.

TERM OF THE PLAN.

     (a) Effective Date. The Plan shall be effective as of February 2, 1999,
provided it has been approved by the Company's shareholders.

     (b) Expiration Date. The Plan shall terminate on the tenth anniversary of
the Effective Date or, subject to the provisions of Sections 4(d) and 11(a)
above, coincident with the completion of any offering under which the limitation
on the total number of Shares in Section 4(a) above has been reached, if
earlier.

                                        6

                                                                     Exhibit 5.1


            [LETTERHEAD OF SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP]


                                                     February 2, 1999


USEC Inc.
Two Democracy Center
6903 Rockledge Drive
Bethesda, MD  20817

          Re:  USEC Inc.
               Registration Statement on Form S-8
               ----------------------------------

Ladies and Gentlemen:

          We have acted as special counsel to USEC Inc., a Delaware corporation
(the "Company"), in connection with the registration of 11,500,000 shares (the
"Shares") of the Company's common stock, par value $.10 per share (the "Common
Stock"), issuable pursuant to the USEC Inc. 1999 Equity Incentive Plan (the
"Incentive Plan") and the USEC Inc. 1999 Employee Stock Purchase Plan (together
with the Incentive Plan, the "Plans").

          This opinion is being furnished in accordance with the requirements of
Item 601(b)(5) of Regulation S-K under the Securities Act of 1933, as amended
(the "Act").

          In connection with this opinion, we have examined originals or copies,
certified or otherwise identified to our satisfaction, of (i) the Registration
Statement on Form S-8 as filed with the Securities and Exchange Commission (the
"Commission") on February 2, 1999 under the Act (the "Registration Statement");
(ii) a specimen certificate representing the Common Stock; (iii) the Certificate
of Incorporation of the Company, as presently in effect; (iv) the By-laws of the
Company, as presently in effect; (v) the Plans; (vi) certain resolutions of the
Board of Directors of the Company, the Compensation Committee, and the
Compensation Subcommittee of the Board of Directors relating to the issuance and

USEC Inc.
February 2, 1999
Page 2


sale of the Shares and related matters; and (vii) certain resolutions of the
stockholders of the Company relating to the Plans. We have also examined
originals or copies, certified or otherwise identified to our satisfaction, of
such records of the Company and such agreements, certificates of public
officials, certificates of officers or other representatives of the Company and
others, and such other documents, certificates and records as we have deemed
necessary or appropriate as a basis for the opinions set forth herein.

          In our examination, we have assumed the legal capacity of all natural
persons, the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified, conformed or photostatic copies and the
authenticity of the originals of such latter documents. In making our
examination of documents executed or to be executed by parties other than the
Company, we have assumed that such parties had or will have the power, corporate
or other, to enter into and perform all obligations thereunder and have also
assumed the due authorization by all requisite action, corporate or other, and
execution and delivery by such parties of such documents and the validity and
binding effect thereof. As to any facts material to the opinions expressed
herein which we have not independently established or verified, we have relied
upon statements and representations of officers and other representatives of the
Company and others. In rendering the opinion set forth below, we have assumed
that the certificates representing the Shares will be manually signed by one of
the authorized officers of the transfer agent and registrar for the Common Stock
and registered by such transfer agent and registrar and will conform to the
specimen thereof examined by us.

          We have also assumed that each award agreement setting forth the terms
of each grant of options or other awards under the Incentive Plan will be
consistent with Incentive Plan and will be duly authorized and validly executed
and delivered by the parties thereto, and that the consideration received by the
Company for the Shares delivered pursuant to the Plans will be in an amount at
least equal to the par value of such Shares.

USEC Inc.
February 2, 1999
Page 3

          Members of our firm are admitted to the bar in the State of Delaware,
and we do not express any opinion as to the laws of any other jurisdiction.

          Based upon and subject to the foregoing, we are of the opinion that
the Shares have been duly authorized for issuance by the Company and, when
issued and paid for in accordance with the terms and conditions of the Plans,
the Shares will be validly issued and, subject to any restrictions imposed by
the Plans, fully paid and nonassessable.

          We hereby consent to the filing of this opinion with the Commission as
an exhibit to the Registration Statement. We also consent to the reference to
our firm under the caption "Legal Matters" in the Registration Statement. In
giving this consent, we do not thereby admit that we are included in the
category of persons whose consent is required under Section 7 of the Act or the
rules and regulations of the Commission.

                                        Very truly yours,



                                   /s/  Skadden, Arps, Slate, Meagher & Flom LLP

                                                                    Exhibit 23.1

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


As independent public accountants, we hereby consent to the incorporation in
this registration statement of our reports dated July 31, 1998 related to USEC
Inc.'s balance sheets and the related statements of income and cash flows and to
all references to our Firm included in this registration statement.


/s/  Arthur Andersen LLP


Washington, D.C.
February 2, 1999