Exhibit 10.46

                               RETENTION AGREEMENT



      This Retention Agreement (the "Agreement"), dated as of November 17, 1999,
is entered into between Thermo Electron Corporation, a Delaware corporation with
its principal place of business at 81 Wyman Street, Waltham, Massachusetts 02454
(the  "Company"),  and John P.  Appleton  residing at P.O.  Box 2034,  75 Marina
Heights, New Castle, New Hampshire 03854.

      The  Company  has  announced  a  reorganization  plan which  includes  the
potential sale of certain businesses  ("Businesses") of Thermo TerraTech Inc., a
Delaware corporation ("Thermo TerraTech"),  which is a majority-owned subsidiary
of the  Company.  The Company  recognizes  that your past  contributions  to the
Company  and to  Thermo  TerraTech  have  contributed  to the  success  of  both
companies  and that your  continued  involvement  will be necessary in order to,
among other things, facilitate the sale of the Businesses and to assure a smooth
transition  for potential  buyers.  The Company  desires to retain your services
through  March  31,  2002  and in  promoting  and  expediting  the  sale  of the
Businesses  and that you are desirous of being  employed by the Company  through
March 31,  2002 and of  assisting  the Company in  facilitating  the sale of the
Businesses and performing other corporate duties reasonably consistent with your
previous duties with the Company and Thermo  TerraTech as they may be reasonably
assigned to you from time to time. In  consideration of the mutual covenants and
promises  contained  herein,  and other  good and  valuable  consideration,  the
receipt and sufficiency of which are hereby  acknowledged by the parties hereto,
the parties agree as follows:

      1. Term of  Retention.  The Company  hereby  agrees to retain you, and you
hereby agree to continue your  employment  with the Company,  upon the terms set
forth in this  Agreement,  for the period  commencing  on the date  hereof,  and
continuing until the earlier of March 31, 2002 or termination in accordance with
the provisions of Section 4 (such period, the "Retention Period").  For purposes
hereof,  the last day of the Retention Period shall be referred to herein as the
"Retention Termination Date."

      2.  Capacity.  During the term of the  Agreement,  you shall  perform your
normal  managerial work duties and, in addition shall exert your best efforts to
promote and expedite the sale of the  Businesses  and the closing of such sales.
You shall be based at your home office in New Castle,  New Hampshire,  and shall
report to the Chief Operating Officer, Energy and Environment or such officer or
officers of the Company designated by such Chief Operating Officer. In addition,
you will be  available  to  travel  from time to time as your  duties  hereunder
reasonably  require,  consistent with your past business travel on behalf of the
Company and Thermo TerraTech. In no event shall you be required to relocate your
residence.  You shall be  subject  to the  supervision  of,  and shall have such
authority as is  reasonably  delegated to you by, the Chief  Operating  Officer,
Energy and Environment or his designee.
<PAGE>

      You hereby  accept the terms of such  retention and agree to undertake the
duties and responsibilities  inherent in such position and such other duties and
responsibilities  as the Chief Operating Officer,  Energy and Environment or his
designee shall from time to time reasonably assign to you.  Further,  commencing
April 1, 2000 through the end of the Retention  Period,  your employment  status
will be reduced from  full-time to  part-time.  It is  anticipated  that in your
capacity as a part-time  employee,  you will work, on average,  approximately 20
hours per week,  although the parties expect that the nature of your duties will
require you to work  substantially  more than 20 hours during  certain weeks and
substantially  less than 20 hours during other weeks.  You agree to abide by the
rules,  regulations,  instructions,  personnel  practices  and  policies  of the
Company and any  changes  therein  that may be adopted  from time to time by the
Company.

      You may engage in outside consulting and other outside business activities
with  third  parties  or serve in any  part-time  industry,  trade,  profession,
governmental,  or academic position,  provided that such activities and position
do not interfere with your duties hereunder.

      3.    Compensation and Benefits.

3.1 Base  Salary.  The Company  shall pay you, at such times as the Company pays
its employees in general, an annualized base salary at the following rates:

                  a.    From April 1, 1999 through March 31, 2000  -  $225,000
                  b.    From April 1, 2000 through March 31, 2001 -   $112,500
                  c.    From April 1, 2001 through March 31, 2002 -   $112,500

            3.2   Bonus.

                  a. Reference Bonus. For the period from April 1, 1999 to March
31, 2000 ("Fiscal 2000"),  you shall be entitled to participate in the Company's
bonus plan with a  reference  bonus of  $105,000.  You  understand  that you may
receive a bonus of $0 to $210,000  under such plan  depending upon the extent of
the achievement of certain individual performance goals and business objectives.
The goals and  business  objectives  for Fiscal  2000 are set forth on Exhibit A
hereto.

                  b. Additional  Bonus.  For the period  beginning April 1, 2000
and  ending on the  Retention  Termination  Date,  you shall be  entitled  to an
additional  bonus,  in an  amount  to be  determined  by the  Company,  for  the
completion of specific  tasks assigned to you by the Company's  Chief  Operating
Officer, Energy and Environment, including efforts in completing the sale of the
Businesses.  If such tasks are  completed,  you shall be  entitled  to a minimum
bonus of  $100,000  and a maximum  bonus of  $300,000,  the  actual  bonus to be
dependent  upon the degree to which you are able to complete the tasks  assigned
to you. This bonus, if due and payable, will be paid in two annual installments,
with the first installment,  in an amount equal to at least $50,000,  to be paid
on April 1, 2001. This additional bonus will be payable to you at the end of the
Retention  Period.  You agree to use your best  efforts,  business  judgment and
skill in completing such tasks assigned to you.
<PAGE>

            3.3 Fringe  Benefits.  You shall be entitled to  participate  in all
benefit  programs  that the  Company  establishes  and  makes  available  to its
employees  from time to time to the extent that your position,  tenure,  salary,
age,  part-time  status,  health and other  qualifications  make you eligible to
participate,  which programs that exist as of the date of this Agreement are set
forth in Exhibit B, it being  understood  that these  programs may be subject to
change from time to time;  provided,  however, as of April 1, 2000, you will not
continue  to earn  vacation or sick leave.  You shall,  however,  be entitled to
continue to participate in the executive car allowance program and the executive
medical reimbursement program during the Retention Period.

            3.4 Reimbursement of Expenses.  The Company shall promptly reimburse
you for all reasonable travel, entertainment and other expenses incurred or paid
by you in  connection  with,  or related  to, the  performance  of your  duties,
responsibilities  or services under this Agreement,  upon presentation by you of
documentation,   expense  statements,  vouchers  and/or  such  other  supporting
information  as the  Company may  request;  provided,  however,  that the amount
available for such travel,  entertainment  and other  expenses may reasonably be
fixed in advance by the Chief Operating Officer, Energy and Environment.

      4. Termination.  This Agreement shall terminate upon the occurrence of any
of the following:

            4.1 At the election of the Company without Cause (as defined below),
at any time, immediately upon written notice to you;

            4.2 At the  election of the  Company,  for Cause,  immediately  upon
written  notice by the  Company  to you.  For the  purposes  of this  Section 4,
"Cause"  for  termination  shall  mean your (a)  conviction  of a  felony,  or a
misdemeanor involving material fraud or material dishonesty,  (b) material fraud
or material  dishonesty in the course of your employment  with the Company,  (c)
wilful   misconduct  that  is  materially   injurious  to  the  Company  or  its
subsidiaries   and   affiliates  and  (d)  gross  neglect  of  your  duties  and
responsibilities under the terms of this Agreement.

            4.3 Upon your death or disability.  As used in this  Agreement,  the
term  "disability"  shall  mean  your  inability,  due to a  physical  or mental
disability,  for a period of 90 days,  whether  or not  consecutive,  during any
360-day  period to perform the services  contemplated  under this  Agreement.  A
determination  of disability  shall be made by a physician  satisfactory to both
you and the  Company;  provided  that if you and the  Company  do not agree on a
physician,  you and the  Company  shall each  select a  physician  and these two
together shall select a third  physician,  whose  determination as to disability
shall be binding on all parties; or

            4.4 At your  election,  upon not  less  than 30 days  prior  written
notice of termination.
<PAGE>

      5.    Effect of Termination.

            5.1  Termination  by the Company or at your  Election.  In the event
this  Agreement is terminated by the Company  pursuant to Section 4.1 or Section
4.2 or at your  election  pursuant to Section 4.4, the Company  shall pay to you
the  compensation  and benefits which would  otherwise be payable to you through
the date of termination;  provided, however, that if the Agreement is terminated
by the  Company  pursuant  to  Section  4.1,  the  Company  shall also pay you a
severance  payment  of an amount  equal to (i) the  balance  of the base  salary
amounts  otherwise payable to you for the period from the date of termination to
March 31,  2002 as set forth in  Section  3.1 plus (ii) the  difference  between
$100,000 and the amount of  additional  bonus,  if any,  previously  paid to you
pursuant to Section  3.2(b) prior to the date of  termination  plus (iii) if the
termination  occurs prior to March 31, 2000, the bonus amount due and payable to
you pursuant to Section 3.2(a), if any.

            5.2  Termination  for  Death or  Disability.  If this  Agreement  is
terminated  as a result of your  death or  because  of  disability  pursuant  to
Section 4.3, the Company shall pay to your estate or to you, as the case may be,
the  compensation  and benefits which would  otherwise be payable to you through
the date of termination because of death or disability.

            5.3  Survival.  Notwithstanding  anything  herein  to the  contrary,
Sections 8 through 17 of this  Agreement  shall survive the  termination of this
Agreement.

      6. Options.  During the  Retention  Period you shall be entitled to retain
your stock  options in the Company and any of its  subsidiaries,  subject to the
terms and conditions of such options.  On the Retention  Termination Date, these
stock  options will no longer vest and no further  lapsing of the  Company's and
its  subsidiaries'  repurchase  rights will occur.  You will then have until the
earlier of (i) either 90 days or two years after the Retention Termination Date,
depending on the term of the option as specified by the  Company's  Stock Option
Manager or (ii) the expiration of the exercise  period,  to exercise your vested
options; provided,  however,  notwithstanding the foregoing, you will have until
the  expiration  of the  exercise  period of your vested  options in each of the
Company,  Thermo Instrument  Systems Inc., and Thermo TerraTech to exercise such
vested  options.  If you do not exercise  your vested  options by the  specified
deadline,  your options will be  canceled,  and you will have no further  rights
with respect to your options.

      7.  Resignation.  You hereby  agree that on April 1, 2000 you will resign,
effective  as of such date,  all of your  positions as an officer of the Company
and  as an  officer  and  director  of all of  the  Company's  subsidiaries  and
affiliates  other than your  positions as (i) director of Thermo  TerraTech  and
(ii) director of Green Sunrise  Group,  Inc. The Company  agrees that  effective
April 1, 2000,  it shall use its best  efforts  to cause you to  become,  and to
maintain  you as,  non-executive  chairman of the board of  directors  of Thermo
TerraTech if Thermo  TerraTech is a public  company on such date.  The Company's
obligation  to use its best  efforts to maintain you as  non-executive  chairman
shall cease when Thermo  TerraTech is no longer a public company.  Further,  you
hereby agree that on the Retention  Termination Date you will resign,  effective
as of such date,  your  position as director and  non-executive  chairman of the
board of directors of Thermo  TerraTech and as director of Green Sunrise  Group,
Inc.

      8. Cooperation:  You agree to reasonably cooperate with the Company at the
Company's  sole cost and expense with respect to all matters  arising  during or
related  to  your  employment,  including  but not  limited  to  cooperation  in
connection  with any  governmental  investigation,  litigation  or regulatory or
other  proceeding which may have arisen or which may arise following the signing
of this Agreement.
<PAGE>

            9.  Waiver of Jury  Trial:  Each of the  parties  hereby  expressly,
knowingly  and  voluntarily  waives all benefit and  advantage of any right to a
trial by jury,  and each agrees that he or it will not at any time insist  upon,
or plead or in any manner  whatsoever claim or take the benefit or advantage of,
a trial by jury in any action arising in connection with this Agreement.

      10.  Restriction on Purchase or Sale of Common Stock:  You understand that
you will  continue to be a "Reporting  Person" for purposes of Section 16 of the
Securities  Exchange  Act of  1934  (the  "Exchange  Act"),  and the  rules  and
regulations promulgated  thereunder,  for the period ending on the date which is
the  earlier of (i) the date that the shares of Thermo  TerraTech  are no longer
registered  under  Section 12 of the  Exchange Act and (ii) six months after the
Retention  Termination  Date,  and that during  that period you are  required to
preclear  transactions in the Company's and its affiliates'  securities with the
Company's Stock Transaction  Coordinator,  Ms. Pauline I. Northern.  The Company
agrees  to  continue  to  provide  you  with   notices,   reminders   and  other
communications and assistance  provided by the Company to its officers to assist
them in their compliance with Section 16 of the Exchange Act. You are also urged
to contact the Corporate Secretary of the Company, Ms. Sandra L. Lambert, should
you have any questions regarding compliance with the insider trading regulations
under the federal securities laws.

      11. Loans.  You have an outstanding  loan balance of $61,867.50  under the
ThermoRetec  Corporation  Stock Holding  Assistance Plan and an outstanding loan
balance of $137,607.00 under the Thermo TerraTech Stock Holding Assistance Plan.
You hereby agree that  promptly  upon  consummation  of the  proposed  merger of
Thermo  Retec with the  Company,  you will repay in full the entire  outstanding
loan balance of $61,867.50 under the ThermoRetec Stock Holding  Assistance Plan.
Further,  you agree that on the Retention  Termination  Date, you will repay the
entire  outstanding  loan  balance  under the  Thermo  TerraTech  Stock  Holding
Assistance Plan by selling back to the Company all or part, as necessary, of the
20,000  shares of Thermo  TerraTech  common stock you acquired  under the Thermo
TerraTech Stock Holding Assistance Plan or, if applicable, the shares of Company
common stock into which such shares may have been  converted  (the  "Shares") at
their then current  market price.  The amount to be paid to you for the purchase
of these Shares will be applied to your  outstanding  loan balance  reducing the
amount of the  outstanding  loan balance.  If after such Shares are sold,  there
remains an  outstanding  loan balance,  then such remaining loan balance will be
forgiven and will be deemed to be additional  gross wages,  and as such, will be
reported as wages on your W-2 statement. Also, you agree that until such loan is
paid off,  you will  provide  security  to the  Company,  as may  reasonably  be
requested,  to secure your obligations  under such outstanding  loan,  including
pledging such Shares to the Company.

      12. Notices.  All notices required or permitted under this Agreement shall
be in writing  and shall be deemed  effective  upon  personal  delivery  or upon
deposit in the United  States Post Office,  by  registered  or  certified  mail,
postage prepaid,  addressed to the other party at the address shown above, or at
such other address or addresses as either party shall  designate to the other in
accordance with this Section 12.
<PAGE>

      13. Entire  Agreement.  This Agreement  constitutes  the entire  agreement
between the parties and  supersedes  all prior  agreements  and  understandings,
whether  written or oral,  relating  to the  subject  matter of this  Agreement;
provided, however, nothing contained herein is intended to or shall supersede or
modify your Executive Retention Agreement with the Company.

      14. Amendment. This Agreement may be amended or modified only by a written
instrument executed by all of the parties hereto.

      15.  Governing  Law.  This  Agreement  and  all  issues  relating  to this
Agreement  and the  transactions  contemplated  hereby  shall  be  governed  by,
enforced under and construed in accordance with the laws of the  Commonwealth of
Massachusetts  without  giving effect to any choice or conflict of law provision
or rule that would cause the application of laws of any jurisdiction  other than
those of the Commonwealth of Massachusetts.

      16. Successors and Assigns. This Agreement shall be binding upon and inure
to the benefit of all of the parties hereto and their respective  successors and
assigns, including any corporation with which, or into which, the Company may be
merged or which may  succeed to its  respective  assets or  business;  provided,
however, that your obligations are personal and shall not be assigned by you.

      17.   Miscellaneous.

            17.1 No delay or omission by the  Company or you in  exercising  any
right under this Agreement shall operate as a waiver of that or any other right.
A waiver or consent  given by the  Company or you on any one  occasion  shall be
effective only in that instance and shall not be construed as a bar or waiver of
any right on any other occasion.

            17.2  The  captions  of the  sections  of  this  Agreement  are  for
convenience of reference only and in no way define, limit or affect the scope or
substance of any section of this Agreement.

            17.3 In case any  provision  of this  Agreement  shall  be  invalid,
illegal or otherwise unenforceable, the validity, legality and enforceability of
the remaining provisions shall in no way be affected or impaired thereby.








<PAGE>


      IN WITNESS WHEREOF,  the parties hereto have executed this Agreement as of
the day and year set forth above.


                                   THERMO ELECTRON CORPORATION



                                   By:
                                            -----------------------------------
                                   Title:   Chief Operating Officer, Energy
                                            and Environment




                                            ----------------------------------
                                            John P. Appleton



<PAGE>


                                    Exhibit A


     Goals for fiscal 2000:

-    As soon as  possible  but no  later  than  December  31,  1999  identify  a
     qualified replacement

-    Meet 1999  calendar  year budget (JPA CY 99) dated  January 7, 1999 (before
     any agreed upon restructuring charges or reserves).

-    Prepare a career  development  and  succession  plan for  TerraTech and its
     subsidiaries by December 31, 1999.


-    Provide assistance, as requested, in order to facilitate the roll-up of the
     TerraTech subsidiaries into Thermo Electron by February 28, 2000.

-    Assist in the evaluation and potential sale of some or all of the TerraTech
     business units.

-    Perform such other duties as may be assigned to you in accordance  with the
     Agreement by the Chief  Operating  Officer,  Energy and  Environment of the
     Company.



<PAGE>


                                    Exhibit B


1.    Health Plans
      (a)    Prudential Comprehensive Medical Plan
      (b)    Tufts Health Plan Point of Service
      (c)    Tufts Health Plan (HMO)
      (d)    Harvard Pilgrim Health Care (HMO)

2.    Dental Plans
      (a)    Prudential Dental Basic
      (b)    Prudential Dental Plus

3.    Life Insurance and Accidental Death and Dismemberment (AD&D) (On a reduced
      basis based on your hours worked and upon the attainment of age 65)

4.    Business Travel Accident Insurance

5.    Thermo Electron Choice Plan

6.    Employee Stock Purchase Plan


All as more fully described in the Thermo Electron Corporation  Corporate Office
Orientation Booklet.