Part 21 Report - 1998-271

 
 

ACCESSION #: 9805280008



                                             Illinois Power Company

                                             Clinton Power Station

                                             P. O. Box 678

                                             Clinton, IL 61727

                                             Tel 217 935 5623

                                             Fax 217 935 4632



                                             Walter G.  MacFarland IV

                                             Senior Vice President

ILLINOIS                                     and Chief Nuclear Officer

   POWER

                                                  U-603004

An Illinova Company                               4F.140

                                                  May 15, 1998



Docket No.  50-461



                                                  10CFR21.21

Document Control Desk

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555



Subject:  10CFR21 Final Report 21-98-001: ITT Barton Model 580A Series

          Differential Pressure Indicating Switch Operating Force

          Concerns



Dear Madam or Sir:



     On December 22, 1997, ITT Barton issued an Industry Advisory memo to

Illinois Power (IP) identifying a condition potentially affecting ITT

Barton Models 580A, 581A, 583A, and 583B, safety-related differential

pressure indicating switches supplied with certification to IEEE-323/344

qualifications.  ITT Barton identified that the miniature switches used

inside the indicated instruments may have operating forces too low to

preclude switch contact chatter in some installations when subjected to

seismic induced vibrations.



     ITT Barton had originally certified that these switches would not

experience contact chatter during seismic loadings of up to 12 Gs, as

long as the force required to operate the internal miniature switches is

high (i.e., between 76 and 95 grains).  ITT Barton performs operating

force selection testing where all switches with operating force between

76 and 95 grams are identified and marked with a blue paint spot.  All

remaining switches are marked with a yellow paint spot.  ITT Barton

discovered that their manufacturing system had allowed the yellow paint

spot switches to be used along with the blue paint spot switches in

assembly of Models 580A, 581A, 583A, and 583B differential pressure

indicating switches supplied with IEEE 323/344 certification to ITT

Barton Qualification Reports R3-580A-9, R3-580A-10, R3-580A-29 or to

Westinghouse with Certification to ITT Barton Baseline Documents 0580-

11395, 0581-10325, and 0581-10225.  The use of the low operating force

miniature switches instead of the originally qualified high operating

force miniature switches reduces the seismic qualification level from 12

Gs to 4 Gs (peak spectral acceleration).



     IP determined that this issue was potentially reportable under the

provisions of 10CFR21 on January 7, 1998.  Condition Report 1-98-01-056

was initiated to track investigation and resolution of this issue.  IP

notified the NRC via letter U-602952





                                                       U-603004

                                                       Page 2



dated March 6, 1998, that the evaluation of this issue under the

provisions of 10CFR21 was not complete.



     The evaluation of this issue is now complete and IP concludes that

this issue is not reportable under the provisions of 10CFR21 for Clinton

Power Station (CPS).  The basis for the not reportable conclusion is that

four potentially affected safety-related differential pressure indication

switches were identified at CPS; an four are installed in the plant.  Two

of the four potentially affected units were inspected and found

acceptable.  A seismic evaluation of the remaining two potentially

affected units, not available for inspection due to plant conditions,

identified that the peak spectral acceleration calculated at the mounting

locations of these units is less than 4 Gs.  Therefore, CPS is not

adversely affected by this issue.



     Additional information about this issue may be obtained by

contacting R. D. Weber, Supervisor-Procurement Engineering, at (217) 935-

8881, extension 3785.



                                        Sincerely your



                                        Walter G.  MacFarland, IV

                                        Senior Vice President and

                                        Chief Nuclear Officer



RSF/mlh



cc:  NRC Clinton Licensing Project Manager

     NRC Resident Inspector

     Regional Administrator, Region III, USNRC

     Illinois Department of Nuclear Safety

     INPO Records Center

     ITT Barton





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