Exhibit 10.31


                    Amendments to Certain Stock Option Plans
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Effective  as of  February  7, 2002,  all frozen  stock  option  plans of Thermo
Electron Corporation (the "Company") and all stock option plans of the Company's
subsidiaries  assumed by the  Company were amended as follows:

-    to clarify the language  regarding  restricted stock awards to provide that
     any  dividends  received on  restricted  stock would also be subject to the
     restrictions of the restricted stock;

-    to  delete  all  provisions  permitting  the  Company  to make a loan to an
     optionee in order to fund the  purchase of shares upon the  exercise of the
     option;

-    to provide  that  options  can only be  exercised  in  accordance  with the
     instructions established by the plan administrator;

-    to  provide  that  obligations  to pay any  federal,  state or local  taxes
     required  to be  withheld  in  accordance  with  the  plan  administrator's
     instructions;

-    amended to provide  that stock  purchased  on the  exercise of an option be
     paid for in accordance with the plan administrator's instructions;

-    to include a list of adjustments the Board may make upon recapitalizations,
     mergers  and  the  like  to  the  "adjustments  in  the  event  of  certain
     transactions" provision; and

-    to  make  the  "administration"  provision  consistent  with  that  of  the
     Company's 2001 Equity Incentive Plan, as amended.