ML20198C961
| ML20198C961 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 10/10/1985 |
| From: | Bruce Watson, Watson R CAROLINA POWER & LIGHT CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| CON-NRC-395, REF-PT21-85, REF-PT21-85-470-000 218, HO-850465-(O), PT21-85-470, PT21-85-470-000, NUDOCS 8511120232 | |
| Download: ML20198C961 (5) | |
Text
So-</oo Cp&L Carolma Power & Light Company
- 'c 15 A 8
- 3 7 HARRIS NUCLEAR PROJECT P. O. Box 165 New Hill, North Carolina 27562 SCT1otscs File Number:
SHF/10-13510E NRC-395 Letter Number:
HO-850465 (0)
Dr. J. Nelson Grace United States Nuclear Regulat.ory Commission q
Region II 101 Marietta Street, Northwest (Suite 2900)
Atlanta, Georgia 10323 CAROLINA POWER & LICllT COMPANY SilEARON HARRIS NUCLEAR POWER PLANT i
1986 - 900,000 KV - UNIT 1 MAIN TRANSFER PANELS -
SERIES 31 (LSR) LATCilING SWITCil RELAYS, ITEM 218
Dear Dr. Grace:
Attached is an i'nterim report on the subject item, which was deemed reportable per the provisions of 10CFR50.55 (c) and 10CFR, Part 21 on September 10, 1985. CP&L is pursuing this matter, and it is currently projected that corrective action and submission of the final report will be accomplished by December 20, 1985.
Thank you for your consideration in this matter.
i Yours very truly, R. A. Watson Vice President i
Shearon llarris Nuclear Power Plant RAW:jsb j
Attachment l
ces Messrs. J. M. Taylor (NRC) i C. Maxwell (NRC - SUNPP)
NBI-OSI 9511120232 851010 ig gDR ADOCM 0 go
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i r e a 7
s CAROLINA POWER AND LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT LNIT 1 INTERIM REPORT DETECTABLE FAILURES OF LATCHING RELAYS IN MAIN TRANSFER PANELS OCTOBER 3, 1985 REPORTABLE UNDER 10CFR50.55(e) and 10CFR, Part 21 IBMD-WKJC01-OS4
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SUBJECT:
Shearon Harris Nuclear Power Plant, Unit 1 10CFR50.55(e) and 10CFR, Part 21, reportable failures of the latching switch relays in the safe shutdown transfer system used upon evacuation of the main control room.
ITEM:
Latching switch relays (31 LSR Series) from the main transfer panels 1A-SA and IB-SB.
PANEL SUPPLIED BY:
System Controls, Iron Mountain, Michigan RELAY SWITCHES MANUFACTURED BY:
Electro Switch Corp., Weymouth, Massachasetts NATURE OF DEFICIENCY:
The Unit I transfer panels, containing the subject relays, have been received and installed at the Shearon Harris plant. Subject latching switch relay used is not unique to the Shearon Harris plant.
A detectable failure was found that could render that part of the safe shutdown system inoperable when electrically transferred to the auxiliary control panel upon main control room evacuation.
Since the start of preliminary testing the following failures have occurred:
1.
Sixteen (16) 31 LSR Series latching switch relays located in the main transfer panals 1A-SA and 1B-SB have been identified as being defective; thirteen (13) with burned coils and three (3) with open contacts.
2.
Inspection of relays removed from the main transfer panels and returned to. Electro Switch showed a high percentage of blades with gaps "out of tolerance" to manufacturing' tolerances (greater than.032 inches). Further inspection of relays taken from the auxiliary transfer panels showed these samples as having blade gaps within manufacturing tolerances.
IBND-WKJC01-OS4
3.
The burned relay coils occurred while testing the panels and inspection of these relays by Electro Switch did not reveal the cause for burning of the coils. Testing of out of stock relays (31 LSR) by Electro Switch duplicating the circuit application at Shearon Harris proved inconclusive.
Therefore additional testing will be done jointly by CP&L and Ebasco at the plant.
DATE PROBLEM REPORTED:
On September 10, 1985 CP&L (N. J. Chiangi) notified the NRC (Mr. P. Fredrickson) that this item was reportable under provisions of 10CFR50.55(e) and 10CFR, Part 21.
SCOPE OF PROBLEM:
During main control room evacuation the subject relays transfer the plant safe shutdown controls from the main control room panels to the auxiliary control panel.
Failure of any relay would constitute an incomplete transfer of the safe shutdown systems.
SAFETY IMPLICATIONS:
The failure of any of these relays to successfully transfer the safe shutdown systems to the auxiliary control panel, during main control room evacuation, could result in delaying or inhibiting that portion of the plant safe shutdown capability.
4 REASON INCIDENT IS REPORTABLE:
Portions of the safe shutdown system could be rendered inoperable.
CORRECTIVE ACTIONS:
1.
The 31 LSR relays are being returned to Electro Switch for contact and blade replacement, cleaning and relubricating of the solenoid and associated latching mechanism, and retesting of the relays to original specifications.
2.
Additional corrective action will be done, if required, upon conclusive results of the additional testing.
IBMD-WKJC01-OS4
FINAL REPORT:
A final report will be issued when rework, corrective action, and satisfactory testing of the transfer panel is completed. The projected date for this final report is December 20, 1985.
I l
I i.
IBMD-WKJC01 054
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