AMENDMENT NO. 5 dated as of September 30, 2008 (this “Amendment”), to the CREDIT
AGREEMENT dated as of August 2, 2004, as amended pursuant to that certain
Incremental Term Loan Assumption Agreement and Amendment No. 1 dated as of
April 1, 2005, that certain Incremental Term Loan Assumption Agreement and
Amendment No. 2 dated as of March 24, 2006, as amended as of April 21, 2006,
that certain Incremental Term Loan Assumption Agreement and Amendment No. 3
dated as of June 30, 2006, and that certain Amendment No. 4 dated as of
February 6, 2007 (as so amended, the “Credit Agreement”), among ALION SCIENCE
AND TECHNOLOGY CORPORATION (the “Borrower”), the Subsidiary Guarantors listed on
the signature pages hereto (solely with respect to Sections 4, 6, 7, 8, 10, 11
and 12 hereof), the lenders from time to time party to the Credit Agreement (the
“Lenders”) and CREDIT SUISSE (formerly known as Credit Suisse First Boston), as
administrative agent (in such capacity, the “Administrative Agent”) and as
collateral agent for the Lenders.

A. Pursuant to the Credit Agreement, the Lenders have extended, and have agreed
to extend, credit to the Borrower.

B. The Borrower has requested certain amendments to the Credit Agreement as set
forth herein, and the Lenders have agreed to such request on and subject to the
terms and conditions of this Amendment.

Accordingly, in consideration of the mutual agreements herein contained and
other good and valuable consideration, the sufficiency and receipt of which are
hereby acknowledged, the parties hereto agree as follows:

SECTION 1. Defined Terms; Interpretation; Etc. Capitalized terms used and not
defined herein shall have the meanings assigned to such terms in the Credit
Agreement. The rules of construction set forth in Section 1.02 of the Credit
Agreement shall apply equally to this Amendment. This Amendment shall be a “Loan
Document” for all purposes of the Credit Agreement and the other Loan Documents.

SECTION 2. Amendments to Credit Agreement. Effective as of September 30, 2008:

(a) Section 1.01 of the Credit Agreement is hereby amended by inserting the
following defined term in the appropriate alphabetical order therein:

“Original Maximum Senior Secured Leverage Ratio” shall mean, on any date of
determination, the maximum Senior Secured Leverage Ratio permitted at such date
under Section 6.13 without giving effect to the changes made to such Section by
Amendment No. 5 dated as of September 30, 2008, to this Agreement.

(b) The definition of the term “Adjusted LIBO Rate” set forth in Section 1.01 of
the Credit Agreement is hereby amended and restated in its entirety to read as
follows:

“Adjusted LIBO Rate” shall mean, with respect to any Eurodollar Borrowing for
any Interest Period, an interest rate per annum equal to the greater of
(a) 3.50% per annum and (b) the product of (i) the LIBO Rate in effect for such
Interest Period and (ii) Statutory Reserves.

(c) The definition of the term “Alternate Base Rate” set forth in Section 1.01
of the Credit Agreement is hereby amended and restated in its entirety to read
as follows:

“Alternate Base Rate” shall mean, for any day, a rate per annum equal to the
greatest of (a) the Prime Rate in effect on such day, (b) the Federal Funds
Effective Rate in effect on such day plus 1/2 of 1% and (c) 4.50% per annum. If
the Administrative Agent shall have determined (which determination shall be
conclusive absent manifest error) that it is unable to ascertain the Federal
Funds Effective Rate for any reason, including the inability or failure of the
Administrative Agent to obtain sufficient quotations in accordance with the
terms of the definition thereof, the Alternate Base Rate shall be determined
without regard to clause (b) of the preceding sentence until the circumstances
giving rise to such inability no longer exist. Any change in the Alternate Base
Rate due to a change in the Prime Rate or the Federal Funds Effective Rate shall
be effective on the effective date of such change in the Prime Rate or the
Federal Funds Effective Rate, as the case may be.

(d) The definition of the term “Applicable Percentage” set forth in Section 1.01
of the Credit Agreement is hereby amended and restated in its entirety to read
as follows:

“Applicable Percentage” shall mean, except as otherwise provided in the
applicable Incremental Term Loan Assumption Agreement with respect to any Other
Term Loan, for any day, (a) with respect to any Eurodollar Loan, 6.00%, and
(b) with respect to any ABR Loan (including any Swingline Loan), 5.00%.
Notwithstanding the foregoing, if the Revolving Credit Maturity Date shall be
extended, or if the Revolving Credit Commitments shall otherwise be refinanced
or replaced, and in connection with such extension, refinancing or replacement
or at any time thereafter the “Applicable Percentage” or similar component of
the interest rate applicable to loans to be made under such extended, refinanced
or replaced revolving credit commitments would exceed the Applicable Percentage
then in effect for Term Loans hereunder by more than 50 basis points (the
portion of such excess above 50 basis points being referred to herein as the
“Rate Differential”), then the Applicable Percentage for Term Loans hereunder
shall be automatically increased, effective as of the date of any such increase
in respect of the revolving credit commitments, by an amount equal to the Rate
Differential.

(e) Section 1.03 (Pro Forma Calculations) of the Credit Agreement is hereby
amended by inserting the words “the Senior Secured Leverage Ratio,” immediately
following the words “as permitted pursuant to the terms hereof,” contained
therein.

(f) Section 2.13(d) of the Credit Agreement is hereby amended by deleting the
words “50% (or, if the Leverage Ratio at the end of such fiscal year shall have
been less than 2.0 to 1.0, 25%)” therefrom and substituting therefor “100%”.

(g) Section 2.13(e) of the Credit Agreement is hereby amended by inserting
immediately after the words “Section 6.01” contained therein the words “(other
than Section 6.01(s))”.

(h) Section 5.04 (Financial Statements, Reports, etc.) of the Credit Agreement
is hereby amended by (i) deleting the word “and” at the end of the paragraph
(i) thereof, (ii) redesignating paragraph (j) thereof as paragraph (k) and
(iii) adding the following as a new paragraph (j) thereof:

(j) within 30 days after the end of each of the first two months of each fiscal
quarter, its internally prepared summary financial statements, in a form
reasonably satisfactory to the Administrative Agent, showing the consolidated
financial position of the Borrower and the Subsidiaries as of the close of such
month and the results of operations and the operations of the Subsidiaries for
such month and the elapsed portion of the fiscal year, and comparative figures
for the same periods in the immediately preceding fiscal year.

(i) Section 6.01 (Indebtedness) of the Credit Agreement is hereby amended by
(i) deleting the word “and” at the end of paragraph (q) thereof, (ii) deleting
the period at the end of paragraph (r) thereof and substituting “; and”
therefor, and (iii) adding the following as a new paragraph (s) thereto:

(s) Indebtedness of the Borrower (which may be Guaranteed by any Loan Party) the
Net Cash Proceeds of which are used to prepay Term Loans (including the payment
of accrued interest thereon), in whole or in part; provided that (i) such
Indebtedness (x) matures no less than 120 days after the Term Loan Maturity
Date, (y) requires no scheduled payment of principal prior to its maturity and
(z) contains non-economic covenants, events of default, remedies and other
provisions, and is in form and substance, reasonably satisfactory to the
Administrative Agent, and (ii) the initial issuance of Indebtedness under this
Section 6.01(s) shall be in an aggregate principal amount of not less than
$50,000,000.

(j) The last paragraph of Section 6.01 (Indebtedness) of the Credit Agreement is
hereby amended by inserting immediately after the words “other than” contained
therein the words “Indebtedness incurred under Section 6.01(s),”.

(k) Section 6.02 (Liens) of the Credit Agreement is hereby amended by adding the
following as a new paragraph (p) thereto:

(p) Liens on any Collateral to secure Indebtedness incurred pursuant to
Section 6.01(s); provided that such Liens are junior and subordinated in
priority to the Liens securing the Obligations pursuant to an intercreditor
agreement in form and substance satisfactory to the Administrative Agent.

(l) Section 6.04(k) (Investments) of the Credit Agreement is hereby amended by
inserting the words “at any time outstanding” immediately following the words
“does not exceed $15,000,000 in the aggregate” contained therein.

(m) Section 6.06(a)(iii) (Restricted Payments) of the Credit Agreement is hereby
amended and restated in its entirety to read as follows:

      (iii) so long as no Default or Event of Default shall have occurred and be
continuing or would result therefrom, the Borrower may repurchase its Equity
Interests owned by directors, officers and employees of the Borrower or the
Subsidiaries or make payments to directors, officers and employees of the
Borrower or the Subsidiaries (x) in connection with Warrants, stock options,
stock appreciation rights, “phantom” stock plans or similar equity incentives or
equity based incentives pursuant to management or other incentive plans or
(y) in connection with the death or disability of such directors, officers and
employees, in the case of both (x) and (y) in an aggregate amount not to exceed
$20,000,000; provided that, except for payments of up to $1,800,000 in the
aggregate in respect of phantom stock rights vested as of September 30, 2008, no
payments may be made pursuant to clause (x) above to Bahman Atefi or Stacy
Mendler unless, at the time thereof and after giving effect thereto and to any
financing therefor, the Borrower would be in pro forma compliance with the
Original Maximum Senior Secured Leverage Ratio, and  

(n) Section 6.06(a)(iv)(E) (Restricted Payments) of the Credit Agreement is
hereby amended by inserting immediately after the words “Sections 6.12 and 6.13”
set forth therein the words “and the Original Maximum Senior Secured Leverage
Ratio”.

(o) Section 6.06(b)(ii) (Restrictive Agreements) of the Credit Agreement is
hereby amended by deleting the words “Indebtedness of any Loan Party” contained
therein and substituting therefor the words “Obligations of any Loan Party”.

(p) The last sentence of Section 6.09(c)(i) (Other Indebtedness and Agreements)
of the Credit Agreement is hereby amended and restated in its entirety to read
as follows:

      Notwithstanding the foregoing, so long as at the time thereof and after
giving effect thereto and to any financing therefor, (w) no Default or Event of
Default shall have occurred and be continuing, (x) the Borrower would be in pro
forma compliance with Sections 6.12 and 6.13, (y) there would be at least
$10,000,000 of unused and available Revolving Credit Commitments and (z) other
than with respect to the $3,000,000 principal payment scheduled to be made on
November 3, 2008, the Borrower would be in pro forma compliance with the
Original Maximum Senior Secured Leverage Ratio, the Borrower may prepay, redeem,
retire or otherwise acquire for consideration the Seller Subordinated Notes in
whole or in part.  

(q) Section 6.12 (Interest Coverage Ratio) of the Credit Agreement is hereby
amended and restated in its entirety to read as follows:

SECTION 6.12 Interest Coverage Ratio. Permit the Interest Coverage Ratio for any
period of four consecutive fiscal quarters, in each case taken as one accounting
period, ending during any period set forth below to be less than the ratio set
forth opposite such period below:

      Period   Ratio
July 1, 2008 through September 30, 2008
October 1, 2008 through December 31, 2008
January 1, 2009 through June 30, 2009
July 1, 2009 through September 30, 2009
Thereafter
  1.20 to 1.00
1.10 to 1.00
1.05 to 1.00
1.00 to 1.00
1.35 to 1.00

(r) Section 6.13 (Maximum Senior Secured Leverage Ratio) of the Credit Agreement
is hereby amended and restated in its entirety to read as follows:

SECTION 6.13 Maximum Senior Secured Leverage Ratio. Permit the Senior Secured
Leverage Ratio at the end of any fiscal quarter during a period set forth below
to be greater than the ratio set forth opposite such period below:

      Period   Ratio
July 1, 2008 through December 31, 2008
January 1, 2009 through September 30, 2009
Thereafter
  4.10 to 1.00
4.25 to 1.00
3.00 to 1.00

(s) Section 6.15 (Earn-Out Obligations) of the Credit Agreement is hereby
amended by deleting the words “Section 6.14” contained therein and substituting
therefor the words “Section 6.13”, and by inserting the words “Senior Secured”
immediately before the words “Leverage Ratio” in both places in which those
words appear therein.

SECTION 3. Representations and Warranties. To induce the other parties hereto to
enter into this Amendment, the Borrower represents and warrants to the
Administrative Agent and each of the Lenders that, as of the Amendment No. 5
Effective Date and after giving effect to this Amendment:

(a) This Amendment has been duly authorized, executed and delivered by each Loan
Party party hereto, and constitutes a legal, valid and binding obligation of
such Loan Party in accordance with its terms. The Credit Agreement (as amended
hereby) constitutes a legal, valid and binding obligation of the Borrower in
accordance with its terms.

(b) The representations and warranties set forth in Article III of the Credit
Agreement are true and correct in all material respects on and as of the
Amendment No. 5 Effective Date with the same effect as though made on and as of
the Amendment No. 5 Effective Date, except to the extent such representations
and warranties expressly relate to an earlier date (in which case such
representations and warranties were true and correct in all material respects as
of such earlier date).

(c) No Default or Event of Default has occurred and is continuing.

SECTION 4. Waiver. To the extent any court of applicable jurisdiction shall
determine that this Amendment is not entered into with effect as of
September 30, 2008, then and only to the extent Borrower may not have complied,
the Required Lenders hereby waive compliance by the Borrower with the provisions
of Section 6.12 (Interest Coverage Ratio) with respect to the period of the four
consecutive fiscal quarters ending September 30, 2008 and Section 6.13 (Maximum
Senior Secured Leverage Ratio) with respect to the fiscal quarter ending
September 30, 2008.

SECTION 5. Amendment Fee. The Borrower agrees to pay on the Amendment No. 5
Effective Date to the Administrative Agent, for the account of each Lender that
executes and delivers a copy of this Amendment to the Administrative Agent (or
its counsel) at or prior to 5:00 p.m. (New York City time) on October 2, 2008
(the “Signing Date”), an amendment fee (the “Amendment Fee”) in an amount equal
to 0.75% of the aggregate principal amount of the Term Loans and Revolving
Credit Commitment of such Lender outstanding on the Signing Date. The Amendment
Fee shall be payable on and subject to the occurrence of the Amendment No. 5
Effective Date. The Amendment Fee shall be payable in immediately available
funds and shall not be refundable.

SECTION 6. Effectiveness. This Amendment shall become effective as of
September 30, 2008, on the date (the “Amendment No. 5 Effective Date”) that the
Administrative Agent shall have received (a) counterparts of this Amendment
that, when taken together, bear the signatures of (i) the Borrower, (ii) each
Subsidiary Guarantor and (iii) the Required Lenders and (b) the Amendment Fee.

SECTION 7. Effect of Amendment. Except as expressly set forth herein, this
Amendment shall not by implication or otherwise limit, impair, constitute a
waiver of, or otherwise affect the rights and remedies of the Lenders, the
Administrative Agent, the Collateral Agent or the Borrower under the Credit
Agreement or any other Loan Document, and shall not alter, modify, amend or in
any way affect any of the terms, conditions, obligations, covenants or
agreements contained in the Credit Agreement or any other Loan Document, all of
which are ratified and affirmed in all respects and shall continue in full force
and effect. Nothing herein shall be deemed to entitle any Loan Party to a
consent to, or a waiver, amendment, modification or other change of, any of the
terms, conditions, obligations, covenants or agreements contained in the Credit
Agreement or any other Loan Document in similar or different circumstances. This
Amendment shall apply and be effective only with respect to the provisions of
the Credit Agreement specifically referred to herein. After the date hereof, any
reference to the Credit Agreement shall mean the Credit Agreement, as modified
hereby.

SECTION 8. Consent and Reaffirmation. Each Subsidiary Guarantor hereby consents
to this Amendment and the transactions contemplated hereby, and each Loan Party
hereby (a) agrees that, notwithstanding the effectiveness of this Amendment, the
Guarantee and Collateral Agreement and each of the other Security Documents
continue to be in full force and effect, (b) confirms its guarantee of the
Obligations (with respect to each Subsidiary Guarantor) and its grant of a
security interest in its assets as Collateral therefor, all as provided in the
Loan Documents as originally executed and (c) acknowledges that such guarantee
and/or grant continue in full force and effect in respect of, and to secure, the
Obligations under the Credit Agreement (as amended hereby) and the other Loan
Documents.

SECTION 9. Expenses. The Borrower agrees to reimburse the Administrative Agent
for all reasonable out-of-pocket expenses incurred in connection with this
Amendment in accordance with the Credit Agreement, including the reasonable
fees, charges and disbursements of counsel for the Administrative Agent.

SECTION 10. Counterparts. This Amendment may be executed in any number of
counterparts and by different parties hereto in separate counterparts, each of
which when so executed and delivered shall be deemed an original, but all such
counterparts together shall constitute but one and the same contract. Delivery
of an executed counterpart of a signature page of this Amendment by facsimile or
electronic transmission shall be as effective as delivery of a manually executed
counterpart hereof.

SECTION 11. Applicable Law. THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED
IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

SECTION 12. Headings. The headings of this Amendment are for purposes of
reference only and shall not limit or otherwise affect the meaning hereof.

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IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be duly
executed by
their respective authorized officers as of the day and year first above written.

      ALION SCIENCE AND TECHNOLOGY CORPORATION,
By /s/ Michael J. Alber

Name:
Title:
  Michael J. Alber
Senior VP and Acting CFO

          HUMAN FACTORS APPLICATIONS, INC.,       By     /s/ Michael J. Alber  
  Name: Michael J. Alber     Title: Treasurer

          ALION-METI CORPORATION       By     /s/ Michael J. Alber     Name:
Michael J. Alber     Title: Treasurer

          ALION-CATI CORPORATION       By     /s/ Michael J. Alber     Name:
Michael J. Alber     Title: Treasurer

          ALION-JJMA CORPORATION       By     /s/ Michael J. Alber     Name:
Michael J. Alber     Title: Treasurer

          ALION-BMH CORPORATION       By     /s/ Michael J. Alber     Name:
Michael J. Alber     Title: Treasurer

          WASHINGTON CONSULTING, INC.       By     /s/ Michael J. Alber    
Name: Michael J. Alber     Title: Treasurer

          ALION-MA&D CORPORATION       By     /s/ Michael J. Alber     Name:
Michael J. Alber     Title: Treasurer

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          WASHINGTON CONSULTING GOVERNMENT SERVICES, INC.       By     /s/
Joshua J. Izenberg     Name: Joshua J. Izenberg     Title: Secretary

CREDIT SUISSE, CAYMAN ISLANDS BRANCH,
individually as a Lender and as Administrative Agent,

By /s/ Robert Hetu
Name: Robert Hetu
Title: Managing Director

By /s/ Christopher Day
Name: Christopher Day
Title: Associate

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