<PAGE>
                                                         Exhibit 10(l)


                            JOINT SECURITY AGREEMENT

          AGREEMENT made as of this 31st day, of March, 1995, by and among
NUCLEAR METALS, INC., a Massachusetts corporation ("Nuclear Metals"), CAROLINA
METALS, INC., a Delaware corporation "Carolina Metals"); together with Nuclear
Metals, "Borrowers"'), and STATE STREET BANK AND TRUST COMPANY, a Massachusetts
chartered trust company ""Bank-").


                              W I T N E S S E T H:

     WHEREAS, the Borrowers have entered into a Credit Agreement with Bank of
even date herewith (the "Credit Agreement") providing for the establishment by
Bank of a credit facility in favor of the Company in the aggregate principal
amount of $4,650,000;

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, it is hereby agreed as follows:

     1.   SECURITY INTEREST. The Borrowers grant Ban a security interest
("Security Interest") in all accounts, inventory and general intangibles (as
such terms are defined by the Uniform Commercial Code), in which either Borrower
now has or hereafter acquires any rights and the proceeds therefrom (including,
without limitation, proceeds of insurance and proceeds in deposit accounts) and
accessions thereto, all as more particularly defined in EXHIBIT A (the
"Collateral").

     2.   OBLIGATIONS.  The Security Interest shall secure the following
obligations (herein the "Obligations"):

          (a)  The prompt and complete payment when due (whether by acceleration
or otherwise) of the Revolving Credit (as defined in the Credit Agreement);


<PAGE>


          (b)  The prompt and complete payment when due (whether by acceleration
or otherwise) of the Term Credit (as defined in the Credit Agreement);

          (c)  The prompt and complete payment when due of all obligations of
the Borrowers with respect to L/C's (as defined in the Credit Agreement);

          (d)  Any and all other obligations of the Borrowers under the Credit
Agreement or under and other document, agreement or instrument executed in
connection with the Credit Agreement;

          (e)  Any and all obligations of either Borrower in connection with,
related to or arising from the Bonds (as defined in the Credit Agreement); and

          (f)  Any and all other liabilities and obligations of every name and
nature whatsoever of either Borrower to Bank whether such liabilities and
obligations be direct or indirect, absolute or contingent, secured or unsecured,
now existing or hereafter arising or acquired, due or to become due including,
without limitation and without regard as to whether or not contemplated at the
time of this Agreement, any extensions of credit hereinafter made by Bank to
either Borrower (including any such extension pursuant to a foreign exchange
line of credit or any liability or obligation of either Borrower to Bank arising
from any foreign exchange transaction), any obligations of either Borrower
acquired by Bank, and any guaranties by either Borrower of obligations owed by
others to Bank.

     3.   FINANCING, STATEMENTS AND OTHER ACTION.  The Borrowers agree to do all
acts which Bank deems necessary or desirable to protect and enforce the Security
Interest including, but not limited to, the execution of financing,
continuation, amendment and termination statements and similar instruments.
Each Borrower hereby irrevocably appoints


                                       -2-

<PAGE>


Bank as its attorney-in-fact (which power is coupled with an interest) to
execute financing, continuation, amendment and termination statements and
similar instruments; provided, that Bank shall exercise this power only after
Bank has requested that such Borrower execute such statements and instruments
and such Borrower does not so execute and deliver to Bank the subject statements
and instruments within two days of such request.

     4.   BORROWERS PLACES OF BUSINESS.  The Borrowers jointly and severally
represent  and warrant that their respective places of business, chief executive
office, the location where the records concerning their respective accounts and
contract rights are located and the record owners of any real estate on which
any of the Collateral is located are as set forth on EXHIBIT B attached hereto.
The Borrowers agree to notify Bank of the addition or discontinuance of any
place of business, chief executive office or an, change in the information
contained on EXHIBIT B.  None of the Collateral shall be removed from the
locations specified on EXHIBIT B other than sales in the ordinary course of
business unless Bank is given thirty (30) days prior written notice of such
removal, which notice shall state the location or locations to which the
Collateral will be removed.  The Borrowers jointly represent and warrant that
all of the Collateral presently is located at the locations set forth on
EXHIBIT B and agrees that the Collateral will remain at such locations and at
such other locations of which Bank receives notice in accordance with this
Paragraph 4.

     5.   NAME.  The Borrowers Jointly represent and warrant that their precise
legal names are set forth in the introduction to this Agreement and agree to
notify Bank immediately of any change in such legal names.

     6.   ENCUMBRANCES.  Each Borrower represents and warrants that it has title
to the


                                       -3-

<PAGE>


Collateral in which it has rights and that there are no sums owed or claims,
liens, security interests or other encumbrances against the Collateral other
than those permitted by the Credit Agreement.  The Borrowers agree to notify
Bank of any lien (except inchoate liens arising by the operation of law),
security interest or other encumbrance securing an obligation in excess of
$50,000 against the Collateral (even though permitted by the Credit Agreement).
Borrowers shall defend the Collateral against any claim, lien, security interest
or other encumbrance adverse to Bank, except for liens permitted by the Credit
Agreement.

     7.   MAINTENANCE OF COLLATERAL.  The Borrowers shall preserve the
Collateral for the benefit of Bank.  Without limiting the generality of the
foregoing, the Borrowers shall:

          (a)  sell inventory only in the ordinary course of business;

          (b)  preserve all beneficial contract rights to the extent
commercially  reasonable;

          (c)  take commercially reasonable steps to collect all accounts; and

          (d)  pay all taxes, assessments or other charges on the Collateral
when due, except to the extent otherwise permitted by the Credit Agreement.

     8.   COLLECTION.  Bank may communicate with account debtors in order to
verify the existence, amount and terms of any accounts or contract rights.  The
Borrowers will maintain such lockbox or blocked accounts as Bank shall specify.
All proceeds of Collateral in the possession of the officers, employees or
agents of the Borrowers shall be held in trust for the benefit of Bank.  All
proceeds of Collateral including, without limitation, collections from accounts
and proceeds from cash sales of Collateral shall be deposited into such lockbox
or blocked accounts or remitted directly to Bank.


                                       -4-

<PAGE>


     At any time after the occurrence and during the continuance of an Event of
Default, Bank (a) may notify account debtors of the Security Interest and
require that payments on accounts and returns of goods be made directly to Bank;
(b) may require the Borrowers to notify their respective account debtors and
indicate on all billings that payments and returns are to be made directly to
Bank; and (c) may collect, compromise, endorse, sell or otherwise deal with the
accounts or proceeds thereof in its own name or in the name of either Borrower.

     If any of the Borrowers' accounts or contract rights arise out of contracts
with a  governmental body subject to the Federal Assignment of Claims Act or a
similar statute, upon request of Bank, the Borrowers shall execute any
instruments and take any action required by law to ensure that all monies due
and to become due under such contract shall be paid directly to Bank.

     9.   INSURANCE.  The Borrowers shall maintain insurance covering the
Collateral as provided in the Credit Agreement.  All such insurance policies
with respect to Collateral shall be written so as to be payable in the event of
loss directly to Bank, shall provide for thirty (30) days prior written notice
to Bank of cancellation or modification, and shall contain an endorsement
providing that the insurer cannot withhold payment to Bank on account of any
action by the Borrowers.  Bank is hereby irrevocably appointed as attorney-in-
fact (which power is coupled with an interest) to collect the proceeds of such
insurance, to settle any claims with the insurers in the event of loss or
damage, to endorse settlement drafts, to cancel, assign or surrender any
insurance policies; provided, however, that Bank will not


                                       -5-

<PAGE>


exercise the foregoing power of attorney except after the occurrence and during
the continuance of an Event of Default.

     10.  ADDITIONAL PROVISIONS CONCERNING THE COLLATERAL.

          (a)  Each Borrower hereby irrevocably appoints Bank its attorney-in-
fact (which such power of attorney is coupled with an interest) with full
authority in the place and stead of such Borrower and in the name thereof, from
time to time after the occurrence and during the continuation of an Event of
Default, to take any of the following actions or execute any of the following
instruments which Bank may deem necessary or advisable to accomplish the
purposes of this Agreement:  (i) to ask, demand, collect, sue for, recover,
compound, receive, and give acquittance and receipts for moneys due and to
become due under or in respect of any of the Collateral; (ii) to receive,
endorse, and collect any checks, drafts, letters of credit, or other
instruments, documents, and chattel paper in connection with clause (i) above;
(iii) to sign each such Borrower's name on any invoice or bill of lading
relating to any account, on drafts against customers, on schedules and
assignments of accounts, on notices of assignment, financing statements and
other public records, on verification of accounts and on notices to customers
(including notices directing make payment directly to Bank); (iv) to notify the
post office authorities to change the address for delivery of its mail to an
address designated by Bank; (v) to receive, open and process all mail addressed
to either Borrower; (vi) to send requests for verification of accounts to
customers; and (vii) to file any claims or take any action or institute any
proceedings which Bank may deem necessary or desirable for the collection of any
of the Collateral or otherwise to enforce the rights of Bank with respect to any
of the Collateral.  Bank agrees that it will


                                       -6-

<PAGE>


exercise the foregoing power of attorney in a commercially reasonable manner.

          (b)  If either Borrower fails to perform any agreement contained
herein, Bank may itself perform, or cause performance of, such agreement or
obligation, and the reasonable costs and expenses of Bank incurred in connection
therewith shall be payable by the Borrowers on demand and shall be secured by
the Collateral.  All such expenditures shall bear interest at the Prime Rate (as
defined in the Credit Agreement) plus five percent (5%).

          (c)  The powers conferred on Bank under this Agreement are solely to
protect its interest in the Collateral and shall not impose any duty upon Bank
to exercise any such powers.  Except for the safe custody of any Collateral in
its possession and the accounting for moneys actually received by it hereunder,
Bank shall have no duty as to any Collateral or as to the taking, of any
necessary steps to preserve rights against prior parties or any other rights
pertaining to any Collateral.

          (d)  Anything herein to the contrary notwithstanding, (1) the
Borrowers shall remain liable under any contracts and agreements relating to the
Collateral to the extent set forth therein to perform all of its obligations
thereunder to the same extent as if this Agreement had not been executed; (ii)
the exercise by Bank of any of its rights hereunder shall not release the
Borrowers from any of its obligations under the contracts and agreements
relating to the Collateral; and (iii) Bank shall not have any obligation or
liability by reason of this Agreement under any contracts and agreements
relating to the Collateral, nor shall Bank be obligated to perform any of the
obligations or duties of either Borrower thereunder or to take any action to
collect or enforce any claim for payment assigned hereunder.

     11.  INTENTIONALLY OMITTED.


                                       -7-

<PAGE>


     12.  DEFAULT.  If any one or more of the following events (herein referred
to as "Events of Default") shall occur:

          (a)  Either Borrower shall fall to perform or observe any provision of
this Agreement and such default shall continue for a period of seven (7) days
after written notice from Bank; or

          (b)  An Event of Default shall have occurred under Article V of the
Agreement;

     then, Bank shall have (a) the right to accelerate any or all of the
Obligations, and (b) all of the rights and remedies set forth in Section 13
below.

     13.  REMEDIES.  Bank shall have all of the rights and remedies of a secured
party under the Uniform Commercial Code and shall have full power and authority
to sell or otherwise dispose of the Collateral or any part thereof.  Any such
sale or other disposition, subject to the provisions of applicable law, may be
by public or private proceedings and may be made by one or more contracts, as a
unit or in parcels, at such time and place, by such method, in such manner and
on such terms as Bank may determine.  Except as required by law, such sale or
other disposition may be made without advertisement or notice of any kind or to
any person.  Where reasonable notification of the time or place of such sale or
other disposition is required by law, such requirement shall have been met if
such notice is delivered as provided in the Agreement, at least ten (10) days
before the time of such sale or other disposition.  Upon notice from Bank, the
Borrowers shall assemble the Collateral at a time and place specified by Bank.
To the extent permitted by law, Bank or any other holder of the Obligations may
buy any or all of the Collateral upon any sale thereof.  To the extent


                                       -8-

<PAGE>


permitted by law, upon any such sale or sales, the Collateral so purchased shall
be held by the purchaser absolutely free from any claims or rights of whatsoever
kind or nature, including any equity of redemption or any similar rights, all
such equity of redemption and any similar rights being hereby expressly waived
and released by the Borrowers.  In the event any consent, approval or
authorization of any governmental agency shall be necessary to effectuate any
such sale or sales, the Borrowers shall execute, as necessary, all applications
or other instruments as may be required.

     At any time after the occurrence of an Event of Default, Bank may commence
proceedings in any court of competent jurisdiction for the appointment of a
receiver (which term shall include a receiver-manager) of the Collateral or of
any part thereof.  At any time after the occurrence of an Event of Default, Bank
may, if permitted without the commencement of a proceeding, appoint any person
to be a receiver of the Collateral or any part thereof and may remove any
receiver so appointed and appoint another in his stead.  Any such receiver
appointed by Bank, or a court at the request of Bank, shall have power (i) to
take possession of the Collateral or any part thereof; (ii) to carry on the
business of the Borrowers; (iii) to borrow money on the security of the
Collateral for the maintenance, preservation or protection of the Collateral or
any part thereof or for the carrying on of the business of the Borrowers; and
(iv) to sell, lease or otherwise dispose of the whole or any part of the
Collateral at public auction, by public tender or by private sale, either for
cash or upon credit, at such time and upon such terms and conditions as the
receiver may determine; provided that Bank shall not be in an, way responsible
for any misconduct or negligence of any such receiver.


                                       -9-

<PAGE>


     Upon written notice to the Borrowers, the Borrowers shall execute and
deliver to Bank a written assignment or assignments of all of their respective
rights under any lease of Collateral.  If the consent of the lessor is required
with respect to any assignment or hereunder, such assignment shall not be
effective until such consent is obtained.  Each Borrower hereby irrevocably
appoints Bank its attorney-in-fact (which power is coupled with an interest) to
execute assignments and subleases in favor of Bank, provided that Bank shall
exercise this power only after Bank has requested that such Borrower execute
such assignment and it does not so execute and deliver to Bank the subject
assignment within two days of such request.

     14.  PROCEEDS.  After deducting all reasonable costs and expenses of
collection, custody, sale or other disposition or delivery (including legal
costs and reasonable attorneys' fees) and all other charges due against the
Collateral, the residue of the proceeds of any such sale or other disposition
shall be applied to the payment of the Obligations and any surplus shall be
returned to the Borrowers, except as otherwise provided by law.  The Borrowers
shall be liable for any deficiency in payment of the Obligations, including all
reasonable costs and expenses of collection, custody, sale or other disposition
or delivery and all other charges due against the Collateral, as hereinbefore
enumerated.

     15.  WAIVERS.  To the extent permitted by law, the Borrowers and any third
party providing credit enhancement with respect to the Obligations ("Secondary
Party") hereby waive demand for payment, notice of dishonor or protest, rights
of redemption, prior notice of the appointment of a receiver and all other
notices of any kind except notices specifically required hereby or by the Credit
Agreement.  Bank may modify the liability of any


                                      -10-

<PAGE>


Secondary Party and release any Collateral provided by such Secondary Party
without giving notice to the Borrowers or any other Secondary Party.  Such
modifications, changes, renewals, releases or other actions shall in no way
affect the obligations of the Borrowers or any Secondary Party hereunder.

     16.  EXPENSE.  The Borrowers agree to pay, indemnify and hold harmless Bank
and the nominees of Bank from and against all costs and expenses (including
taxes, if any) arising out of or incurred in connection with the administration
and sale of Collateral and all reasonable costs and expenses (including
reasonable legal fees) incurred by Bank in connection with the negotiation,
preparation, execution, amendment, interpretation, termination or enforcement of
this Agreement.

     17.  INTENTIONALLY OMITTED.

     18.  SETOFF.  Any sums due from Bank to either Borrower or any property of
either Borrower in the possession of Bank may be held and treated as Collateral
and, after the occurrence of an Event of Default, may be applied to the payment
of the Obligations regardless of the adequacy of the Collateral.

     19.  MODIFICATION.  This Agreement may be modified or amended only in
writing signed by each of the parties hereto.

     20.  NOTICES.  All notices and other communications hereunder shall be
deemed to have been sufficiently given if delivered as provided in the Credit
Agreement.

     21.  WAIVERS.  No course of dealing between the Borrowers and Bank, nor any
delay in exercising, on the part of Bank, any right, power or privilege
hereunder, shall operate as a waiver thereof nor shall any single or partial
exercise of any right, power or


                                      -11-

<PAGE>


privilege hereunder preclude any other or further exercise thereof or the
exercise of any other right, power or privileges.  The rights and remedies
hereunder are cumulative and are in addition to, and not exclusive of, any
rights or remedies provided by law.

     22.  GOVERNING LAW; BINDING EFFECT; COUNTERPARTS.  This Agreement shall be
construed in accordance with and governed by the laws of the Commonwealth of
Massachusetts.  This Agreement shall be binding upon and inure to the benefit of
the parties hereto and their respective successors and assigns, including any
other holder or holders of any Obligations and may be executed in two or more
counterparts, each of which shall together constitute one and the same
agreement.

     23.  SEVERABILITY.  The invalidity or unenforceability of any provision
hereof shall in no way affect the validity or enforceability of any other
provision hereof.


                                      -12-

<PAGE>


     IN WITNESS WHEREOF, the parties hereto have executed this Security
Agreement as of the date first above written.


                                   NUCLEAR METALS, INC.


                                   By:     /s/ James M. Spiezio
                                       ------------------------------------
                                        Name:  James M. Spiezio
                                        Title:  V.P. Finance


                                   CAROLINA METALS, INC.


                                   By:    /s/ James M. Spiezio
                                       ------------------------------------
                                        Name:  James M. Spiezio
                                        Title:  President


                                   STATE STREET BANK AND TRUST
                                   COMPANY


                                   By:     /s/ William R. Dewey IV
                                       ------------------------------------
                                        Name:  William R. Dewey IV
                                        Title:  Assistant Vice President



                                      -13-

<PAGE>


                                    EXHIBIT A


     A continuing security interest in:

     (a)  accounts including without limitation all accounts receivable, sums
due from factors, contracts, contract rights, notes, bills, drafts, acceptances,
instruments, documents, chattel paper, chooses in action, and all other debts,
obligations and liabilities in whatever form, owing to either Borrower from any
person, firm or corporation or any other legal entity, whether now existing or
hereafter arising, now or hereafter received by or belonging or owing to either
Borrower, for goods sold by it or for services rendered by it, or however
otherwise same may have been established or created, all guaranties and
securities therefor, all right, title and interest of either Borrower in the
merchandise or services which gave rise thereto, including the rights of
reclamation and stoppage in transit and all rights of an unpaid seller of
merchandise or services;

     (b)  inventory including, without limitation, all goods, merchandise, raw
materials, goods and work in process, finished goods, and other tangible
personal property now owned or hereafter acquired and held for sale or lease or
furnished or to be furnished under contracts of service or consumed in the
Borrowers' businesses;

     (c)  general intangibles including without limitation, tax refunds and all
proceeds of insurance; and

     (d)  all products and proceeds from any of the foregoing including without
limitation all proceeds of credit, fire or other insurance and deposit accounts.



<PAGE>

                                    EXHIBIT B

            List of Locations of Places of Business and Collateral of
                              Nuclear Metals, Inc.


The Borrowers represent and warrant that with respect to Nuclear Metals, Inc.:

     (a)  its principal place of business is:

          Concord, Massachusetts

     (b)  its chief executive office is:

          Concord, Massachusetts

     (c)  its records concerning accounts located at:

          Concord, Massachusetts

     (d)  its only other places of business are:

          Barnwell, South Carolina
          Arlington, Virginia

     (e)  all of the Tangible Collateral is located at its places of business.

The Borrowers represent and warrant that with respect to Carolina Metals, Inc.:

     (a)  its principal place of business is:

          Barnwell, South Carolina

     (b)  its chief executive office is:

          Concord, Massachusetts

     (c)  its records concerning accounts are located at:

          Concord, Massachusetts

     (d)  its only other places of business are:

          None

     (e)  all of the Tangible Collateral is located at its places of business.