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                                                                 Exhibit 10(hh)

    THE SECURITIES REPRESENTED BY THIS DEBENTURE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED ("ACT") AND MAY NOT BE OFFERED OR SOLD,
TRANSFERRED, PLEDGED, HYPOTHECATED OR OTHERWISE DISPOSED OF EXCEPT PURSUANT TO
(i) AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT, (ii) TO THE EXTENT
APPLICABLE, RULE 144 UNDER THE ACT (OR ANY SIMILAR RULE UNDER SUCH ACT RELATING
TO THE DISPOSITION OF SECURITIES), OR (iii) AN OPINION OF COUNSEL, IF SUCH
OPINION SHALL BE REASONABLY SATISFACTORY TO COUNSEL TO THE ISSUER, THAT AN
EXEMPTION FROM REGISTRATION UNDER SUCH ACT IS AVAILABLE.

                              NUCLEAR METALS, INC.
                           10% Subordinated Debenture
                             Due September 21, 2000


($500,000.00)                                                September 22, 1997


    Nuclear Metals, Inc., a Massachusetts corporation (the "Company"), for
value received, hereby promises to pay to Roger Marino or registered assigns
(the "Holder"), the principal sum of Five Hundred Thousand Dollars ($500,000.00)
on September 21, 2000 (the "Maturity Date") with interest from the date hereof
(computed on the basis of a 365-day year) at the rate per annum of ten percent
(10%) until paid in full.   The Company will pay interest in arrears
semi-annually on the last day of each March and of each September (each an
"Interest Payment Date") to the Holder of record.  Interest will accrue from the
most recent date to which interest has been paid or if no interest has been
paid, from the date of issuance of this debenture. 

    1.   General.  This  debenture (the "Debenture") is transferable only by
surrender thereof at the principal office of the Company located at 2229 Main
Street, Concord, Massachusetts  01742, duly endorsed by, or accompanied by a
written instrument of transfer duly executed by, the registered Holder of this
Debenture or his attorney duly authorized in writing and a completed "investor
questionnaire" duly executed by the transferee reasonably satisfactory in form
and substance to the Company.


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    2.   Events of Default.  An "Event of Default" occurs if:

         (a)  the Company defaults in the payment of interest on this Debenture
    when the same becomes due and payable and the default continues for ten
    (10) days after notice thereof is given to the Company;

         (b)  the Company defaults in the payment of the principal of this
    Debenture when the same becomes due and payable and the default continues
    for ten (10) days after notice thereof;

         (c)  the Company, pursuant to or within the meaning of any Bankruptcy
    Law (A) admits in writing its inability to pay its debts generally as they
    become due, (B) commences a voluntary case or proceeding under any
    Bankruptcy Law with respect to itself, (C) consents to the entry of a
    judgment, decree or order for relief against it in an involuntary case or
    proceeding under any Bankruptcy Law, (D) consents to the appointment of a
    bankruptcy trustee (a "Bankruptcy Trustee") of its or for any part of its
    property, (E) consents to or acquiesces in the institution of bankruptcy or
    insolvency proceedings against it, (F) applies for, consents to or
    acquiesces in the appointment of a Bankruptcy Trustee, (G) makes a general
    assignment for the benefit of its creditors, or (H) takes any corporate
    action for any of the foregoing purposes; or

         (d)  a court of competent jurisdiction enters a judgment, decree or
    order for relief in respect of the Company in an involuntary case or
    proceeding under any Bankruptcy Law which shall (A) approve as properly
    filed a petition seeking reorganization, arrangement, adjustment or
    composition in respect of the Company, (B) appoint a Bankruptcy Trustee of
    the Company or for any part of its property, or (C) order the winding-up or
    liquidation of its affairs; and such judgment, decree or order shall remain
    unstayed and in effect for a period of 60 consecutive days; or (D) any
    bankruptcy or insolvency petition or application is filed, or any
    bankruptcy or insolvency proceeding is commenced against the Company and
    such petition, application or proceeding is not dismissed within 60 days.

    The term "Bankruptcy Law" means Title 11, U.S. Code or any similar federal
or state law for the relief of debtors.  

    3.   Remedies.  If an Event of Default (other than an Event of Default
specified in Section 2(c) or 2(d) in respect of the Company) occurs and is
continuing, the Holder may, subject to Section 4 hereof, by notice of the
Company, declare all unpaid principal and accrued interest to the date of
acceleration on the Debenture then outstanding (if not then due and payable) to
be due and payable and, upon any such declaration, the same shall become and be
immediately due and payable.  If an Event of Default specified in Section 2(c)
or 2(d) in respect of the Company occurs, all unpaid principal and accrued
interest on the Debenture then outstanding shall ipso facto become and be
immediately due and payable without any declaration or other act on the part of
any Holder.  The Holder by notice to the Company may rescind an 


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acceleration and its consequences if (i) all existing Events of Default, other
than the non-payment of the principal of the Debenture which has become due
solely by such declaration of acceleration, have been cured or waived, (ii) to
the extent the payment of such interest is lawful, interest on overdue
installments of interest and overdue principal, which has become due otherwise
than by such declaration of acceleration, has been paid, and (iii) the
rescission would not conflict with any judgment or decree of a court of
competent jurisdiction.

    4.   Subordination.  The Company covenants and agrees, for itself and its
successor and assigns, and each Holder hereof, for itself and for any subsequent
holder of this Debenture, by its acceptance hereof, covenants and agrees that
the indebtedness evidenced hereby is hereby expressly subordinated, to the
extent and in the manner hereinafter set forth, in right of payment to the prior
payment for satisfaction in full in cash of all Senior Indebtedness, as
hereinafter defined.

    Until all Senior Indebtedness shall have been performed or paid in full in
cash, (a) the Company shall not, directly or indirectly, and the holder of this
Debenture shall not be permitted to receive any payment on account of this
Debenture and the holder of this Debenture shall not demand or accept from the
Company or any person any such payment or otherwise discharge any part of the
obligations of the Company hereunder and such holder shall not take any action
prejudicial to, or inconsistent with, the priority position of the Senior
Indebtedness over the holder hereof, including, without limitation, declaring
all unpaid principal and accrued interest under this Debenture due and payable,
commencing any action or proceeding against the Company to enforce to collect
this Debenture, or any portion hereof or commencing or joining any "Proceeding"
(as defined below) against the Company, and (b) the holder of this Debenture
shall have no right of subrogation to receive payments or distributions of
assets of the Company applicable to the Senior Indebtedness.  Notwithstanding
the foregoing, so long as no default exists under any agreement or instrument
evidencing any of the Senior Indebtedness, interest and principal may be paid on
this Debenture in accordance with the terms hereof.

    At any meeting of creditors of the Company or in the event of any
proceeding ("Proceeding"), voluntary or involuntary, for the distribution,
division or application of all or part of the assets of the Company, whether
such proceeding be for the liquidation, dissolution or winding up of the Company
or its business, or proceeding for relief under any bankruptcy, reorganization
or insolvency law or any other law relating to relief of debtors, readjustment
of indebtedness, reorganization, arrangement, composition or extension or
otherwise, the holder of the Senior Indebtedness is hereby irrevocably
authorized by the holder of this Debenture at any such meeting or in any such
proceeding:  (a) to prove any claim (by the filing of proof(s) of claim(s) or
otherwise) on account of this Debenture either in its own name or in the name of
the holder hereof; (b) to collect any assets of the Company distributed, divided
or applied by way of dividend or payment, or any securities issued, on account
of this Debenture and apply the same to the Senior Indebtedness; (c) to vote
claims on account of this Debenture to accept or reject any plan for
liquidation, reorganization, arrangement, composition or extension; and (d) to
take generally any action in connection with any such meeting or proceeding
which the holder of this Debenture might otherwise take.


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    Upon the occurrence of any default under any agreement or instrument
evidencing any of the Senior Indebtedness, should any payment be received by the
holder of this Debenture, such payment shall be delivered forthwith to the
holder of the Senior Indebtedness for application to the Senior Indebtedness. 
The holder of the Senior Indebtedness is irrevocably authorized to supply any
required endorsement or assignment.  Until so delivered, any such payment shall
be held by the holder of this Debenture in trust for the holder of the Senior
Indebtedness and shall not be commingled with other funds or property of the
holder of this Debenture.

    Without the necessity of any reservation of rights against or any notice to
or further assent by the holder of this Debenture, any demand for payment of any
Senior Indebtedness made by the holder of the Senior Indebtedness may be
rescinded in whole or in part by such holder, the holder of the Senior
Indebtedness may exercise or refrain from exercising any rights and remedies
against the Company and others, the Senior Indebtedness or any collateral
security or guaranty therefor or right of offset with respect thereto, may be
executed, or released by the holder of Senior Indebtedness, and any agreement or
instrument evidencing, securing or otherwise relating to Senior Indebtedness may
be amended or modified, all without impairing, abridging, releasing or affecting
the subordination provided for herein.  The holder of this Debenture waives any
and all notice of the creation or modification of any Senior Indebtedness and
notice of or proof of reliance by the holder of the Senior Indebtedness upon the
subordination provided for herein.

    For purposes of this Debenture, "Senior Indebtedness" shall include any and
all indebtedness, liabilities, duties, undertakings, warranties, covenants and
agreements (including those of payment or performance) of the Company or any of
its wholly-owned subsidiaries to State Street Bank and Trust Company and its
respective successors or assigns (the "Lender"), of every kind, nature and
description and arising pursuant to the terms of the Forbearance and Amendment
Agreement ("Amendment Agreement") dated as of January 11, 1996 between the
Company, its wholly-owned subsidiary, Carolina Metals, Inc. ("CMI"), and the
Lender, as may be amended, modified, supplemented and/or restated from time to
time, the Loan Documents and Bond Documents, as defined in the Amendment
Agreement, as such Documents may be amended, modified, supplemented and/or
restated from time to time, or otherwise, whether or not the same are: now
existing or hereafter arising; imposed by agreement or by operation of law; due
or not due; absolute or contingent (including any reimbursement obligations
relating to any letter of credit issued for the account of the Company or CMI);
liquidated or unliquidated; voluntary or involuntary, evidenced by a writing;
presently contemplated by the parties; direct or indirect; liabilities or
undertakings of the Company or any of its subsidiaries as surety, guarantor or
endorser with respect to obligations of one or more other parties specifically
described as secured or unsecured, hereafter acquired by the Lender or any of
them by assignment, other transfer or operation of law.  Senior Indebtedness
also shall include any refinancings thereof or replacement financing therefor.

    5.   Interest Limitation.  If a law, which applies to this Debenture and
which sets maximum loan charges, is finally interpreted so that the interest or
other loan charges collected or to be collected in connection with this
Debenture exceed the permitted limits, then:  (i) any 


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<PAGE>


such loan charge shall be reduced by the amount necessary to reduce the charge
to the permitted limit; and (ii) any sums already collected from the Company
which exceeded permitted limits will be refunded to the Company.  The Holder may
choose to make this refund by reducing the principal owed under this Debenture
or by making a direct payment to the Company.

    6.   Consent to Jurisdiction.  The Holder hereby irrevocably agrees that
any legal action or proceedings with respect to this Debenture against the
Company may be brought only in the courts of the United States of America or The
Commonwealth of Massachusetts. By acceptance of this Debenture, the Holder
hereby (i) accepts the exclusive jurisdiction of the aforesaid courts; (ii)
irrevocably agrees to be bound by any judgment of any such court with respect to
this Debenture; and (iii) irrevocably waives, to the fullest extent permitted by
law, any objection which it may now or hereafter have to the laying of venue of
any suit, action or proceedings with respect to this Debenture brought in any
court of the United States of America or The Commonwealth of Massachusetts, and
further irrevocably waives any claim that any such suit, action or proceeding
brought in any such court has been brought in an inconvenient forum.

    7.   Miscellaneous. 
    
         (a)  THIS DEBENTURE SHALL BE GOVERNED BY THE LAWS OF THE COMMONWEALTH
    OF MASSACHUSETTS WITHOUT REFERENCE TO CONFLICTS OF LAWS RULES OR
    PRINCIPLES.

         (b)  The Company and all endorsers of this Debenture hereby waive
    presentment, demand, protest or notice of any kind in connection with the
    delivery, acceptance, performance or enforcement of this Debenture.

         (c)  No provision thereof shall alter or impair the obligation of the
    Company which is absolute and unconditional, to pay the principal and
    interest on this Debenture as herein prescribed.

                                  NUCLEAR METALS, INC.



                                  By:  /s/ George J. Matthews
                                       ----------------------
                                       George J. Matthews
                                       Chairman


Attest:


/s/ Thomas A. Wooters
-----------------------------
Thomas A. Wooters
Clerk


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