ML20071N795
| ML20071N795 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 05/26/1983 |
| From: | Parsons R CAROLINA POWER & LIGHT CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| CON-NRC-73, REF-PT21-83 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8306070231 | |
| Download: ML20071N795 (4) | |
Text
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Carolina Power & Light Company o.
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N P. O. Box 101, New Hill, N. C.
27562 May 26, 1983 D4o
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ua Mr. James P. O'Reilly NRC 4 53 TZ United States Nuclear Regulatory Commission Region II C3 O. *A C
101 Marietta Street, Northwest (Suite 3100)
Atlanta, Georgia 30303 CAROLINA POWER & LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT 1986 900,000 KW - UNITS 1 & 2 MAIN REACTOR TRIP BREAKERS, SHOP ORDER 386, ITEM 130
Dear Mr. O'Reilly:
Attached is an interim report on the subject item which was deemed reportable per the provisions of 10CFR50.55(e) and 10CFR, Part 21, on April 21, 1983. CP&L is pursuing this matter, and it is currently projected that corrective action and submission of the final report will be accomplished by June 30, 1984.
Thank you for your consideration in this matter.
Yours very truly, W ekV*2 ^;^h R. M. Parsons l
Project General Manager
[
Shearon Harris Nuclear Power Plant RMP/sh Attachment cc:
Mr. G. Maxwell (NRC-SHNPP)
Mr. R. Prevatte (NRC-SHNPP)
Mr. V. Stello (NRC) l
'5mc1ALcorW B306070231 830526 M#
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PDR ADOCK 05000400 S
O CAROLINA POWER & LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT UNITS 1 AND 2 INTERIM REPORT SHNPP MAIN REACTOR TRIP BREAKERS ITEM 130 MAY 24, 1983 REPORTABLE UNDER 10CFR50.55(e)
REPORTABLE UNDER 10CFR21 L
SUBJECT:
SHNPP Units 1 and 2 Main Reactor Trip Breakers, Westinghouse Model DS-416 purchased under NSSS contract with Westinghouse NY-435002, Shop Order 386.
ITEM:
Misoperation of the undervoltage attachments.
SUPPLIED RY:
Westinghouse Electric Corporation Switchgear Division.
NATURE OF DEFICIENCY:
A design discrepancy exists concerning a retaining ring on the undervoltage attachment pivot shaf ts.
Specifically, a design change increased the width of a retaining ring, while the groove in which the retaining ring seats, was not changed. This allows improper seating of the retaining ring. The result is that the retaining ring _may detach itself from the pivot shaft with the potential for misoperation of the undervoltage attachment.
I DATE PROBLEM OCCURRED:
On April 12, 1983, Westinghouse informed CP&L (CQL-7343) of a potential problem concerning minimum gap clearances on the same item. On April 21, 1983, Westinghouse informed CP&L (CQL-7360) of a potential problem concerning a retaining. ring design discrepancy on the undervoltage attachment.
-DATE PROBLEM REPORTED:
On April 18, 1983, CP&L (Mr. N. J. Chiangi) notified the NRC (Mr. C. Hehl) that this item was potentially reportable. On April 27, 1983, CP&L (Mr. N. J.
Chiangi) notified the NRC (Mr. A. Hardin) that this item was reportable under 10CFR50.55(e) and 10CFR21.
SCOPE OF PROBLEM:
This deficiency involves two Unit 1 and two Unit 2 Reactor Trip Breakers and two Unit 1 and two Unit 2 Reactor Trip Bypass Breakers.
SAFETY IMPLICATIONS:
The potential for misoperation of the undervoltage attachment could create a condition wherein the reactor trip breakers might not open on automatic demand from the reactor protection system. This could prevent a safe shutdown of the reactor unless I
prompt operator action is taken to " manually" trip the reactor.
REASONS DEFICIENCY REPORTABLE:
This item is reportable because the deficiency reported may affect the ability of safety related equipment to perform its intended function.
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CORRECTIVE ACTION:
1.
Westinghouse has committed to replacing the undervoltage attachments which includes a replacement pivot shaft with wider grooves to accommodate the new retaining ring. Westing-house is developing new procedures for the installation and proper alignment and interface of this attachment with the breaker trip shaft.
. PREVENTATIVE ACTION:
1.
Westinghouse has revised manufacturing drawings and quality control procedures to assure that critical design dimensions are maintained during manufacture.
2.
To prevent trip breaker failure as a result of any undervoltage attachment malfunction, CP&L is reviewing industry information as a precursor to initiating a design change for the automatic dual trip operation by activating both the undervoltage attachment and the shunt coil attachment on receipt of an automatic undervoltage signal from the reactor protection system.
FINAL REPORT:
CP&L expects to complete the corrective action plan and submit a final report by June 30, 1984.
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