<PAGE>   1

                                                          Registration No. 333-

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549
                                      
                                  ----------
                                      
                                   FORM S-8
                                      
                            REGISTRATION STATEMENT
                                    UNDER
                          THE SECURITIES ACT OF 1933
                                      
                              Lightbridge, Inc.
-------------------------------------------------------------------------------
            (Exact Name of Registrant as Specified in Its Charter)
                                      
                                   Delaware
-------------------------------------------------------------------------------
        (State or Other Jurisdiction of Incorporation or Organization)

                                  04-3065140
-------------------------------------------------------------------------------
                     (I.R.S. Employer Identification No.)

                 281 Winter Street, Waltham, Massachusetts            02154
-------------------------------------------------------------------------------
               (Address of Principal Executive Offices)             (Zip Code)

             LIGHTBRIDGE, INC. 1996 EMPLOYEE STOCK PURCHASE PLAN
-------------------------------------------------------------------------------
                            (Full Title of the Plan)
                                      
                              Pamela D.A. Reeve
                    President and Chief Executive Officer
                              Lightbridge, Inc.
                              281 Winter Street
                         Waltham, Massachusetts 02154
-------------------------------------------------------------------------------
                     (Name and Address of Agent for Service)

                                (617) 890-2000
-------------------------------------------------------------------------------
        (Telephone Number, Including Area Code, of Agent For Service)

                               WITH COPIES TO:
                         John D. Patterson, Jr., Esq.
                            Mark L. Johnson, Esq.
                           Foley, Hoag & Eliot LLP
                            One Post Office Square
                         Boston, Massachusetts 02109
                                (617) 832-1000





<PAGE>   2



<TABLE>
                         CALCULATION OF REGISTRATION FEE

<CAPTION>
=====================================================================================
                                                         Proposed
      Title of                         Proposed          Maximum
      Securities        Amount         Maximum           Aggregate     Amount of
      to be             to be          Offering Price    Offering      Registration
      Registered        Registered     Per Share(1)      Price(1)      Fee
-------------------------------------------------------------------------------------

<S>                     <C>            <C>               <C>           <C>        
Common Stock,           100,000        $11.00            $1,100,000    $284(2)
$.01 par value          shares

=====================================================================================


<FN>
      (1) Estimated solely for the purpose of determining the registration fee.

      (2) In accordance with Rules 457 (c) and (h) under the Securities Act 
          of 1933, the calculation is based on 85% of the average of the high 
          and low sale prices reported in the consolidated reporting system of
          the Nasdaq National Market on February 3, 1997.
</TABLE>

                   -------------------------------------------




<PAGE>   3


                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

     The following documents filed with the Securities and Exchange Commission
(the "Commission") are incorporated in this Registration Statement by reference:

     (a) the Prospectus dated September 27, 1996 of Lightbridge, Inc. (the
"Company" or the "Registrant") included in the Company's Registration Statement
on Form S-1 (file number 333-6589), as declared effective by the Commission on
September 25, 1996;

     (b) the description of the Company's Common Stock contained in the
Company's Registration Statement on Form 8-A filed with the Commission on
September 6, 1996 under Section 12 of the Securities Exchange Act of 1934,
including any amendment or description filed for the purpose of updating such
description;

     (c) the Company's Quarterly Report on Form 10-Q for the Quarterly Period
ended September 30, 1996 (file number 000-21319), as filed with the Commission 
on November 14, 1996; and

     (d) all documents subsequently filed by the Company pursuant to Sections 
13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, prior to the
filing of a post-effective amendment which indicates that all securities
offered have been sold or which deregisters all securities then remaining
unsold, shall be deemed to be incorporated by reference in this Registration
Statement and to be part hereof from the date of filing of such documents.

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 Delaware General Corporation Law affords a Delaware
corporation the power to indemnify its present and former directors and offices
under certain conditions. Article SEVENTH of the Company's Amended and Restated
Certificate of Incorporation (the "Restated Charter") provides that the
Company shall indemnify each person who at any time is, or shall have been, a
director or officer of the Company, and is threatened to be or is made a party
to any threatened, pending or completed action, suit or proceeding, whether
civil, criminal, administrative or investigative, by reason of the fact that he
is, or was, a director or officer of the Company, is or was serving at the 
request of the Company as a director, officer, employee, trustee, or agent
of another or served corporation, partnership, joint venture, trust or other
enterprise, against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement incurred in connection with any such action, suit or
proceeding to the maximum extent permitted by the General Corporation Law of
the State of Delaware.

     Section 102(b)(7) of the Delaware Corporation Law gives a Delaware
corporation the power to adopt a charter provision eliminating or limiting the
personal liability of directors to the corporation or its stockholders for
breach of fiduciary duty as directors, provided that such provision may not
eliminate or limit the liability of directors for (i) any breach of the
director's duty of loyalty to the corporation or its stockholders, (ii) any acts



<PAGE>   4


or omissions not in good faith or which involve intentional misconduct or a 
knowing violation of law, (iii) any payment of a dividend or approval of a
stock purchase that is illegal under Section 174 of the Delaware Corporation
Law or (iv) any transaction from which the director derived an improper
personal benefit. Article NINTH of the Restated Charter provides that to the
maximum extent permitted by the General Corporation Law of the State of
Delaware, no director of the Company shall be personally liable to the Company
or to any of its stockholders for monetary damages arising out of such
director's breach of fiduciary duty as a director of the Company. Furthermore,
any amendment to or repeal of the provisions of Article NINTH shall not
apply to nor have any effect on the liability or the alleged liability of any
director of the Corporation with respect to any act or failure to act of such
director occurring prior to such amendment or repeal. A principal effect of
such Article NINTH is to limit or eliminate the potential liability of the
Company's directors for monetary damages arising from breaches of their duty of
care, unless the breach involves one of the four exceptions described in (i)
through (iv) above. 
        
     Section 145 of the Delaware General Corporation Law also affords a Delaware
corporation the power to obtain insurance on behalf of its directors and
officers against liabilities incurred by them in those capacities. The Company
has procured a directors' and officers' liability and company reimbursement
liability insurance policy that (a) insures directors and officers of the
Company against losses (above a deductible amount) arising from certain claims
made against them by reason of certain acts done or attempted by such directors
or officers and (b) insures the Company against losses, (above a deductible
amount) arising from any such claims, but only if the Company is required or
permitted to indemnify such directors or officers for such losses under
statutory or common law or under provisions of the Restated Charter or the
Restated By-Laws.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

     Not applicable.

ITEM 8.  EXHIBITS.

4.1*   Specimen certificate for the Common Stock 

5.1    Opinion of Foley, Hoag & Eliot LLP

10.1*  Lightbridge, Inc. 1996 Employee Stock Purchase Plan 

23.1   Consent of Deloitte & Touche LLP

23.2   Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1)

24.1   Power of Attorney (contained on the signature page)

------------
 * Filed as an exhibit to the Company's Registration Statement on Form S-1
   (file number 333-6589), as declared effective by the Commission on September
   25, 1996 and incorporated herein by reference.

   ITEM 9.  UNDERTAKINGS.

      1. The undersigned Registrant hereby undertakes:

            (a) To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement:




                                      II-2


<PAGE>   5



                     (i) To include any prospectus required by Section 10(a)(3)
              of the Securities Act of 1933;

                     (ii) To reflect in the prospectus any facts or events
              arising after the effective date of the 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 the Registration Statement;

                     (iii) To include any material information with respect to
              the plan of distribution not previously disclosed in the
              Registration Statement or any material change to such information
              in the Registration Statement;

provided, however, that paragraphs 2 (a)(1)(i) and 2 (a)(1)(ii) do not apply if
the information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed by the Registrant pursuant to
Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are
incorporated by reference herein.

            (b) That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered herein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

            (c) 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 offering.

      2. The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the
Registration Statement shall be deemed to be a new registration statement
relating to the securities offered herein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

      3. Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
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, the Registrant 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 Act and will be governed by the final adjudication of
such issue.



      

                                      II-3


<PAGE>   6



                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, 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 the City of Boston, Massachusetts, on this 31st day of January,
1997.


                              LIGHTBRIDGE, INC.



                              By: /s/ PAMELA D.A. REEVE
                                  ----------------------------------------
                                  Pamela D.A. Reeve
                                  President & Chief Executive Officer



                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS that each individual whose signature
appears below constitutes and appoints Pamela D.A. Reeve and William G. Brown,
and each of them, true and lawful attorneys-in-fact and agents with full power
of substitution, for and in name, place and stead, in any and all capacities, to
sign any and all amendments (including post-effective amendments) to this
Registration Statement, and to file the same, with all exhibits thereto, and all
documents in connection therewith, with the Securities and Exchange Commission,
granting unto said attorney-in-facts and agents, and each of them, full power
and authority to do and perform each and every act and thing which they, or any
of them, may deem necessary or advisable to be done in connection with this
Registration Statement, as fully to all intents and purposes as he or she might
or could do in person, hereby ratifying and confirming all that said
attorney-in-facts and agents or any of them, or any substitute or substitutes
for him, any or all of them, may lawfully do or cause to be done by virtue
hereof.

      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities as of January 31, 1997.



Signature                                       Title
---------                                       -----


/s/ PAMELA D.A. REEVE                   President, Chief Executive Officer and
-----------------------------           Director (Principal Executive Officer)
Pamela D.A. Reeve                         



                                      II-4


<PAGE>   7



Signature                                       Title
---------                                       -----


/s/ WILLIAM G. BROWN                   Chief Financial Officer and Treasurer
--------------------------------       (Principal Financial and Accounting 
William G. Brown                       Officer)



/s/ ANDREW I. FILLAT                   Director
--------------------------------
Andrew I. Fillat



/S/ TORRENCE C. HARDER                 Director
--------------------------------
Torrence C. Harder



/s/ DOUGLAS A. KINGSLEY                Director
--------------------------------
Douglas A. Kingsley



/s/ D. QUINN MILLS                     Director
--------------------------------
D. Quinn Mills




                                      II-5


<PAGE>   8

                                  EXHIBIT INDEX
                                  -------------

Exhibit
  No.       Description
------      -----------

 4.1*       Specimen certificate for the Common Stock 

 5.1        Opinion of Foley, Hoag & Eliot LLP

10.1*       Lightbridge, Inc. 1996 Employee Stock Purchase Plan 

23.1        Consent of Deloitte & Touche LLP

23.2        Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1)

24.1        Power of Attorney (contained on the signature page)

----------------
 *   Filed as an exhibit to the Company's Registration Statement on Form S-1
     (file number 333-6589), as declared effective by the Commission on
     September 25, 1996 and incorporated herein by reference
[{"type": "S-8", "sequence": "1", "description": "LIGHTBRIDGE, INC.", "secsgml_size_bytes": 17828}]
{"company-data": {"conformed-name": "LIGHTBRIDGE INC", "cik": "0001017172", "assigned-sic": "4812", "irs-number": "043065140", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-21585", "film-number": "97524912"}, "business-address": {"street1": "281 WINTER ST", "city": "WALTHAM", "state": "MA", "zip": "02154", "phone": "6178321134"}, "mail-address": {"street1": "281 WINTER ST", "city": "WALTHAM", "state": "MA", "zip": "02154"}}
1

                                                          Registration No. 333-

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549
                                      
                                  ----------
                                      
                                   FORM S-8
                                      
                            REGISTRATION STATEMENT
                                    UNDER
                          THE SECURITIES ACT OF 1933
                                      
                              Lightbridge, Inc.
-------------------------------------------------------------------------------
            (Exact Name of Registrant as Specified in Its Charter)
                                      
                                   Delaware
-------------------------------------------------------------------------------
        (State or Other Jurisdiction of Incorporation or Organization)

                                  04-3065140
-------------------------------------------------------------------------------
                     (I.R.S. Employer Identification No.)

                 281 Winter Street, Waltham, Massachusetts            02154
-------------------------------------------------------------------------------
               (Address of Principal Executive Offices)             (Zip Code)

             LIGHTBRIDGE, INC. 1996 EMPLOYEE STOCK PURCHASE PLAN
-------------------------------------------------------------------------------
                            (Full Title of the Plan)
                                      
                              Pamela D.A. Reeve
                    President and Chief Executive Officer
                              Lightbridge, Inc.
                              281 Winter Street
                         Waltham, Massachusetts 02154
-------------------------------------------------------------------------------
                     (Name and Address of Agent for Service)

                                (617) 890-2000
-------------------------------------------------------------------------------
        (Telephone Number, Including Area Code, of Agent For Service)

                               WITH COPIES TO:
                         John D. Patterson, Jr., Esq.
                            Mark L. Johnson, Esq.
                           Foley, Hoag & Eliot LLP
                            One Post Office Square
                         Boston, Massachusetts 02109
                                (617) 832-1000
2

                         CALCULATION OF REGISTRATION FEE
=====================================================================================
                                                         Proposed
      Title of                         Proposed          Maximum
      Securities        Amount         Maximum           Aggregate     Amount of
      to be             to be          Offering Price    Offering      Registration
      Registered        Registered     Per Share(1)      Price(1)      Fee
-------------------------------------------------------------------------------------
Common Stock,           100,000        $11.00            $1,100,000    $284(2)
$.01 par value          shares

=====================================================================================
(1) Estimated solely for the purpose of determining the registration fee.

      (2) In accordance with Rules 457 (c) and (h) under the Securities Act 
          of 1933, the calculation is based on 85% of the average of the high 
          and low sale prices reported in the consolidated reporting system of
          the Nasdaq National Market on February 3, 1997.
-------------------------------------------
3

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

     The following documents filed with the Securities and Exchange Commission
(the "Commission") are incorporated in this Registration Statement by reference:

     (a) the Prospectus dated September 27, 1996 of Lightbridge, Inc. (the
"Company" or the "Registrant") included in the Company's Registration Statement
on Form S-1 (file number 333-6589), as declared effective by the Commission on
September 25, 1996;

     (b) the description of the Company's Common Stock contained in the
Company's Registration Statement on Form 8-A filed with the Commission on
September 6, 1996 under Section 12 of the Securities Exchange Act of 1934,
including any amendment or description filed for the purpose of updating such
description;

     (c) the Company's Quarterly Report on Form 10-Q for the Quarterly Period
ended September 30, 1996 (file number 000-21319), as filed with the Commission 
on November 14, 1996; and

     (d) all documents subsequently filed by the Company pursuant to Sections 
13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, prior to the
filing of a post-effective amendment which indicates that all securities
offered have been sold or which deregisters all securities then remaining
unsold, shall be deemed to be incorporated by reference in this Registration
Statement and to be part hereof from the date of filing of such documents.

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 Delaware General Corporation Law affords a Delaware
corporation the power to indemnify its present and former directors and offices
under certain conditions. Article SEVENTH of the Company's Amended and Restated
Certificate of Incorporation (the "Restated Charter") provides that the
Company shall indemnify each person who at any time is, or shall have been, a
director or officer of the Company, and is threatened to be or is made a party
to any threatened, pending or completed action, suit or proceeding, whether
civil, criminal, administrative or investigative, by reason of the fact that he
is, or was, a director or officer of the Company, is or was serving at the 
request of the Company as a director, officer, employee, trustee, or agent
of another or served corporation, partnership, joint venture, trust or other
enterprise, against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement incurred in connection with any such action, suit or
proceeding to the maximum extent permitted by the General Corporation Law of
the State of Delaware.

     Section 102(b)(7) of the Delaware Corporation Law gives a Delaware
corporation the power to adopt a charter provision eliminating or limiting the
personal liability of directors to the corporation or its stockholders for
breach of fiduciary duty as directors, provided that such provision may not
eliminate or limit the liability of directors for (i) any breach of the
director's duty of loyalty to the corporation or its stockholders, (ii) any acts
4

or omissions not in good faith or which involve intentional misconduct or a 
knowing violation of law, (iii) any payment of a dividend or approval of a
stock purchase that is illegal under Section 174 of the Delaware Corporation
Law or (iv) any transaction from which the director derived an improper
personal benefit. Article NINTH of the Restated Charter provides that to the
maximum extent permitted by the General Corporation Law of the State of
Delaware, no director of the Company shall be personally liable to the Company
or to any of its stockholders for monetary damages arising out of such
director's breach of fiduciary duty as a director of the Company. Furthermore,
any amendment to or repeal of the provisions of Article NINTH shall not
apply to nor have any effect on the liability or the alleged liability of any
director of the Corporation with respect to any act or failure to act of such
director occurring prior to such amendment or repeal. A principal effect of
such Article NINTH is to limit or eliminate the potential liability of the
Company's directors for monetary damages arising from breaches of their duty of
care, unless the breach involves one of the four exceptions described in (i)
through (iv) above. 
        
     Section 145 of the Delaware General Corporation Law also affords a Delaware
corporation the power to obtain insurance on behalf of its directors and
officers against liabilities incurred by them in those capacities. The Company
has procured a directors' and officers' liability and company reimbursement
liability insurance policy that (a) insures directors and officers of the
Company against losses (above a deductible amount) arising from certain claims
made against them by reason of certain acts done or attempted by such directors
or officers and (b) insures the Company against losses, (above a deductible
amount) arising from any such claims, but only if the Company is required or
permitted to indemnify such directors or officers for such losses under
statutory or common law or under provisions of the Restated Charter or the
Restated By-Laws.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

     Not applicable.

ITEM 8.  EXHIBITS.

4.1*   Specimen certificate for the Common Stock 

5.1    Opinion of Foley, Hoag & Eliot LLP

10.1*  Lightbridge, Inc. 1996 Employee Stock Purchase Plan 

23.1   Consent of Deloitte & Touche LLP

23.2   Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1)

24.1   Power of Attorney (contained on the signature page)

------------
 * Filed as an exhibit to the Company's Registration Statement on Form S-1
   (file number 333-6589), as declared effective by the Commission on September
   25, 1996 and incorporated herein by reference.

   ITEM 9.  UNDERTAKINGS.

      1. The undersigned Registrant hereby undertakes:

            (a) To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement:

                                      II-2
5

                     (i) To include any prospectus required by Section 10(a)(3)
              of the Securities Act of 1933;

                     (ii) To reflect in the prospectus any facts or events
              arising after the effective date of the 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 the Registration Statement;

                     (iii) To include any material information with respect to
              the plan of distribution not previously disclosed in the
              Registration Statement or any material change to such information
              in the Registration Statement;

provided, however, that paragraphs 2 (a)(1)(i) and 2 (a)(1)(ii) do not apply if
the information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed by the Registrant pursuant to
Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are
incorporated by reference herein.

            (b) That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered herein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

            (c) 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 offering.

      2. The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the
Registration Statement shall be deemed to be a new registration statement
relating to the securities offered herein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

      3. Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
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, the Registrant 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 Act and will be governed by the final adjudication of
such issue.

      

                                      II-3
6

                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, 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 the City of Boston, Massachusetts, on this 31st day of January,
1997.

                              LIGHTBRIDGE, INC.

                              By: /s/ PAMELA D.A. REEVE
                                  ----------------------------------------
                                  Pamela D.A. Reeve
                                  President & Chief Executive Officer

                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS that each individual whose signature
appears below constitutes and appoints Pamela D.A. Reeve and William G. Brown,
and each of them, true and lawful attorneys-in-fact and agents with full power
of substitution, for and in name, place and stead, in any and all capacities, to
sign any and all amendments (including post-effective amendments) to this
Registration Statement, and to file the same, with all exhibits thereto, and all
documents in connection therewith, with the Securities and Exchange Commission,
granting unto said attorney-in-facts and agents, and each of them, full power
and authority to do and perform each and every act and thing which they, or any
of them, may deem necessary or advisable to be done in connection with this
Registration Statement, as fully to all intents and purposes as he or she might
or could do in person, hereby ratifying and confirming all that said
attorney-in-facts and agents or any of them, or any substitute or substitutes
for him, any or all of them, may lawfully do or cause to be done by virtue
hereof.

      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities as of January 31, 1997.

Signature                                       Title
---------                                       -----

/s/ PAMELA D.A. REEVE                   President, Chief Executive Officer and
-----------------------------           Director (Principal Executive Officer)
Pamela D.A. Reeve                         

                                      II-4
7

Signature                                       Title
---------                                       -----

/s/ WILLIAM G. BROWN                   Chief Financial Officer and Treasurer
--------------------------------       (Principal Financial and Accounting 
William G. Brown                       Officer)

/s/ ANDREW I. FILLAT                   Director
--------------------------------
Andrew I. Fillat

/S/ TORRENCE C. HARDER                 Director
--------------------------------
Torrence C. Harder

/s/ DOUGLAS A. KINGSLEY                Director
--------------------------------
Douglas A. Kingsley

/s/ D. QUINN MILLS                     Director
--------------------------------
D. Quinn Mills

                                      II-5
8

                                  EXHIBIT INDEX
                                  -------------

Exhibit
  No.       Description
------      -----------

 4.1*       Specimen certificate for the Common Stock 

 5.1        Opinion of Foley, Hoag & Eliot LLP

10.1*       Lightbridge, Inc. 1996 Employee Stock Purchase Plan 

23.1        Consent of Deloitte & Touche LLP

23.2        Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1)

24.1        Power of Attorney (contained on the signature page)

----------------
 *   Filed as an exhibit to the Company's Registration Statement on Form S-1
     (file number 333-6589), as declared effective by the Commission on
     September 25, 1996 and incorporated herein by reference