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 *** END OF DOCUMENT ***

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