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                                                                     EXHIBIT 4.4


                                    USEC Inc.
                  EMPLOYEE NONQUALIFIED STOCK OPTION AGREEMENT
                              (Three Year Vesting)


NONQUALIFIED STOCK OPTION AGREEMENT (the "Agreement") dated as of ______________
(the "Date of Grant"), between USEC Inc., a Delaware corporation (the
"Company"), and ____________ (the "Optionee"):


                                R E C I T A L S:
                                - - - - - - - -

The Company has adopted the USEC Inc. 1999 Equity Incentive Plan (the "Plan"),
which Plan is incorporated herein by reference and made a part of this
Agreement. Capitalized terms not otherwise defined herein shall have the same
meanings as in the Plan.

The Committee has determined that it is in the best interests of the Company and
its shareholders to grant the option provided for herein to the Optionee
pursuant to the Plan and the terms set forth herein as an increased incentive to
contribute to the Company's future success and prosperity.

NOW THEREFORE, in consideration of the mutual covenants hereinafter set forth,
the parties hereto agree as follows:

1. Grant of the Option. The Company hereby grants to the Optionee an option (the
"Option") which Option permits the Optionee to purchase all or any part of an
aggregate of _________ Shares at a purchase price of $______ per share (the
"Exercise Price"). The Option granted hereby is intended to be a Non-Qualified
Stock Option and not an Incentive Stock Option.

2. Vesting. Subject to Section 4 hereof, one-third of the Option shall become
exercisable as of the first anniversary of the Date of Grant and an additional
one-third of the Option shall become exercisable on each of the second and third
anniversaries of the Date of Grant. At any time, the "Vested Portion" of the
Option means that portion which (i) shall have become exercisable pursuant to
the terms of this Agreement and (ii) shall not have been previously exercised.

3. Exercise of Option. (a) Subject to the provisions of the Plan and this
Agreement (including Section 4 hereof), the Optionee may exercise all or any
part of the Vested Portion of the Option at any time prior to the fifth
anniversary of the Date of Grant (the "Expiration Date"); provided that the
Option may be exercised with respect to whole Shares only. In no event shall the
Option be exercisable on or after the Expiration Date.

(b) To the extent set forth in subparagraph (a) above, the Option may be
exercised by delivering to the Company at its principal office written notice of
intent to exercise. Such


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notice shall specify the number of Shares for which the Option is being
exercised and shall be accompanied by payment in full, or adequate provision
therefor, of the Exercise Price and any applicable withholding tax. The payment
of the Exercise Price shall be made (i) in cash or (ii) by certified check or
bank draft payable to the order of the Company or (iii) by tendering Shares
which have been owned by the Optionee for at least six months (and which are not
subject to any pledge or other security interest) or (iv) 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 the Exercise Price. The Optionee
may elect to pay all or any portion of the Exercise Price by having Shares with
a Fair Market Value on the date of exercise equal to the Exercise Price withheld
by the Company or sold by a broker-dealer. The payment of withholding tax shall
be subject to Section 8 of this Agreement.

(c) Notwithstanding any other provision of the Plan or this Agreement to the
contrary, no Option may be exercised prior to the completion of any registration
or qualification of such Option or the Shares under applicable state and federal
securities or other laws, or under any ruling or regulation of any government
body or national securities exchange, that the Committee shall in its sole
discretion determine to be necessary or advisable.

(d) Upon the Company's determination that the Option has been validly exercised
as to any of the Shares, the Company shall issue or cause to be issued as
promptly as practicable certificates in the Optionee's name for such Shares.
However, the Company shall not be liable to the Optionee for damages relating to
any delays in issuing the certificates or in the certificates themselves.

4. Termination of Employment. (a) In the event that the Optionee's employment
with the Company is terminated by the Company for Cause or the Optionee breaches
the covenants set forth in Section 9, the Option (whether vested or unvested)
shall be deemed canceled and forfeited in its entirety on the date of the
Optionee's termination of employment.

(b) In the event that the Optionee's employment with the Company is terminated
by the Optionee voluntarily, the unvested portion of the Option shall be deemed
canceled and forfeited on the date of Optionee's termination of employment and
the Vested Portion, if any, of the Option as of the date of such termination
shall remain exercisable for a period of one month following such termination of
employment, and shall thereafter be deemed canceled and forfeited.

(c) In the event that the Optionee's employment with the Company is terminated
by the Company without Cause or by reason of death, Disability or Retirement,
unless otherwise provided by the Committee at the time of such termination, the
Option shall vest in its entirety and shall remain exercisable for a period of
one year following such termination of employment, and shall thereafter be
deemed canceled and forfeited.

5. Change in Control. Upon a Change in Control of the Company, the unvested
portion of the Option shall vest.


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6. No Right to Continued Employment: No Rights as a Shareholder. Neither the
Plan nor this Agreement shall confer on the Optionee any right to continued
employment with the Company. The Optionee shall not have any rights as a
shareholder with respect to any Shares subject to the Option prior to the date
of exercise of the Option.

7. Transferability. Except as provided below, the Option is nontransferable and
may not be assigned, alienated, pledged, attached, sold or otherwise transferred
or encumbered by the Optionee, except by will or the laws of descent and
distribution. Notwithstanding the foregoing, the Optionee may transfer the
Vested Portion 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 transfer is approved by the
Committee and the Optionee does not receive any consideration for the transfer.
Any such transferred portion shall continue to be subject to the same terms and
conditions that were applicable to the Option immediately prior to its transfer
(except that such transferred portion shall not be further transferable by the
transferee). No transfer of the Option shall be effective to bind the Company
unless the Company shall have been furnished with written notice thereof and a
copy of such evidence as the Committee may deem necessary to establish the
validity of the transfer and the acceptance by the transferee of the terms and
conditions hereof.

8. Withholding. The Optionee agrees to make appropriate arrangements with the
Company for satisfaction of any applicable federal, state, local or foreign tax
withholding requirements or like requirements, including the payment to the
Company at the time of any exercise of the Option of all such taxes and
requirements, and the Company shall have the right and is hereby authorized to
withhold from the Shares transferable to the Optionee upon any exercise of the
Option or from any other compensation or other amount owing to the Optionee such
amount (in cash, Shares or other property, as the case may be) as may be
necessary in the opinion of the Company to satisfy all such taxes and
requirements.

9. Confidential Information and Trade Secrets. The Optionee and the Company
agree that certain materials, including, but not limited to, information, data
and other materials relating to customers, development programs, costs,
marketing, trading, investment, sales activities, promotion, credit and
financial data, manufacturing processes, financing methods, plans or the
business and affairs of the Company and its Affiliates, constitute proprietary
confidential information and trade secrets. Accordingly, the Optionee will not
at any time during or after the Optionee's employment with the Company disclose
or use for the Optionee's own benefit or purposes or the benefit or purposes of
any other person, firm, partnership, joint venture, association, corporation or
other business organization, entity or enterprise other than the Company and any
of its Affiliates, any proprietary confidential information or trade secrets,
provided that the foregoing shall not apply to information which is not unique
to the Company or any of its Affiliates or which is generally known to the
industry or the public other than as a result of the Optionee's breach of this
covenant. The Optionee agrees that upon termination of employment with


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the Company for any reason, the Optionee will immediately return to the Company
all memoranda, books, papers, plans, information, letters and other data, and
all copies thereof or therefrom, which in any way relate to the business of the
Company and its Affiliates, except that the Optionee may retain personal notes,
notebooks and diaries. The Optionee further agrees that the Optionee will not
retain or use for the Optionee's account at any time any trade names, trademark
or other proprietary business designation used or owned in connection with the
business of the Company or any of its Affiliates.

10. Remedies. The Optionee acknowledges that a violation or attempted violation
on the Optionee's part of Sections 9 will cause irreparable damage to the
Company, and the Optionee therefore agrees that the Company shall be entitled as
a matter of right to an injunction, out of any court of competent jurisdiction,
restraining any violation or further violation of such promises by the Optionee
or the Optionee's employees, partners or agents. The Optionee agrees that such
right to an injunction is cumulative and in addition to whatever other remedies
the Company may have under law or equity.

11. Failure to Enforce Not A Waiver. The failure of the Company to enforce at
any time any provision of this Agreement shall in no way be construed to be a
waiver of such provision or of any other provision hereof.

12. Securities Laws. Upon the acquisition of any Shares pursuant to the exercise
of the Option, the Optionee or the Optionee's transferee, if applicable, will
make or enter into such written representations, warranties and agreements as
the Company may reasonably request in order to comply with applicable securities
laws, with this Agreement, or as the Company otherwise deems necessary or
advisable.

13. Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Delaware, without regard to the
conflicts of laws provisions thereof.

14. Amendments. This Agreement may be amended or modified at any time by an
instrument in writing signed by the parties hereto.

15. Notices. Any notice, request, instruction or other document given under this
Agreement shall be in writing and shall be addressed and delivered, in the case
of the Company, to the Secretary of the Company at the principal office of the
Company and, in the case of the Optionee, to the Optionee's address as shown in
the records of the Company or to such other address as may be designated in
writing by either party.

16. Award Subject to Plan; Amendments to Award. This Award is subject to the
Plan. The terms and provisions of the Plan as it may be amended from time to
time are hereby incorporated herein by reference. In the event of a conflict
between any term or provision contained herein and a term or provision of the
Plan, the applicable terms and provisions of the Agreement will govern and
prevail.


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17. Counterparts. This Agreement may be executed in two or more counterparts,
each of which shall be an original but all of which together shall represent one
and the same agreement.


IN WITNESS WHEREOF, the parties hereto have executed this Agreement. By
execution of this Agreement, the Optionee acknowledges receipt of a copy of the
Plan.


                                            USEC Inc.



                                            By
                                              ----------------------------------
                                               Vice President, Human Resources
                                               & Administration




                                              ----------------------------------
                                                Name










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