ML20136G243
| ML20136G243 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 12/20/1985 |
| From: | Watson R CAROLINA POWER & LIGHT CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| CON-NRC-410, REF-PT21-85, REF-PT21-86-009-000 218, EFR-851224, HO-850486-(O), IBMD-WKTW01-054, IBMD-WKTW1-54, PT21-86-009-000, PT21-86-9, NUDOCS 8601080063 | |
| Download: ML20136G243 (6) | |
Text
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or Cp&L Carolina Power & Light Company
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HARRIS NUCLEAR PROJECT g
P. O. Box 165 a
New Hill, North Carolina 27562 g
DEC 2 0 Ilgi m
File Number:
SHF/10-13510E NRC-410 Letter Number:
HO-850486 (0)
Q Dr. J. Nelson Grace United States Nuclear Regulatory Commission Region II go-400 101 Marietta Street, Northwest (Suite 2900)
Atlanta, Georgia 30323 CAROLINA POWER & LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT 1986 - 900,000 KV - UNIT 1 MAIN TRANSFER PANELS -
SERIES 31 (LSR) LATCHING SWITCH RELAYS, ITEM 218
Dear Dr. Grace:
Attached is our final report on the subject item, which was deemed reportable per the provisions of~10CFR50.55 (e) and 10CFR, Part 21 on September 10, 1985. With this report, Carolina Power & Light Company considers this matter closed.
If you should have any questions concerning this matter, please do not hesitate to contact me.
Yours very truly, 6N R. A. Watson Vice President Shearon Harris Nuclear Power Plant RAW:ajj' Attachment cc: Messrs. J. M. Taylor (NRC)
C. Maxwell (NRC - SHNPP) 8601000063 851220 PDR ADOCK 05000400 5
S PDR
'O xen
CAROLINA POWER AND LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 FINAL REPORT DETECTABLE FAILURES OF LATCHING RELAYS IN MAIN AND AUXILIARY TRANSFER PANELS i
DECEMBER 13, 1985 REPORTABLE UNDER 10CFR50.55(e) and 10CFR, Part 21 IBMD-WKTW01-0S4
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 and auxiliary transfer panels IA-SA's and IB-SB's.
PANEL SUPPLIED BY:
System Controls, Iron Mountain, Michigan and Reliance Electric, now United Controls, Stone Mountain, Georgia.
RELAY SWITCHES MANUFACTURED BY:
Electro Switch Corp., Weymouth, Massachusetts 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 transfer system inoperable after electrical transfer to the Auxiliary Control Panel (ACP) upon main control room evacuation.
Initial relay testing by Electro Switch proved inconclusive.
Subsequent CP&L/Ebasco testing showed that the cause of the relay failures was binding in the mechanism located in the front IBMD-WKTWO1-OS4
~.
portion of the switch. While this did not affect the original transfer itself (main control room to ACP) it did prevent proper relay set up for re-transfer back to the original configuration (ACP to main control room).
It was this improper re-transfer set-up that resulted in the failed relays when the re-transfer sequence was initiated.
(It should be noted that all observed test failure occurred during the re-transfer sequence, not during the main control room evacuation transfer sequence).
Further analysis of Electro Switch test data at this point supported the CP&L/Ebasco test results.
The results of the performance test enabled CP&L/Ebasco to conclude that:
1.
The 31LSR failures were due to a loss of effectiveness of the lubricant originally applied to the relays.
2.
.The inability of the lubricant to perform as required is' attributed to lubricant contamination of unknown origin.
Based on the performance test results, corrective actions were implemented and re-testing of relays revealed no further failures.
DATE PROBLEM REPORTED:
On September 10, 1985 CP&L (N. J. Chiangi) notified the NRC (Mr. P. Fredrickson) that this iten was reportable under provisions of 10CFR50.55(e) and 10CFR, Part 21.
IBMD-WKTW01-OS4
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. Re-transfer back to the main control room is also accomplished by these relays.
Failure of any relay could 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 could result in inhibiting that portion of the plant safe shutdown transfer capability, until an operator manually completes the transfer.
REASON INCIDENT IS REPORTABLE:
Portions of the safe shutdown transfer system could be rendered temporarily inoperable during a transfer attempt.
CORRECTIVE ACTIONS:
1.
Originally the 31 LSR relays were returned to Electro Switch for contact and blade replacement, surface cleaning and relubricating of the solenoid and associated latching mechanism, and retesting of the relays to original specifications.
IBMD-WKTW01-OS4
e 2.
Subsequently, CP&L completely flushed &
relubricated the mechanical internals of the front portion of the relays. Test failures were not observed after this action was taken.
The relays have now been internally relubricated by either CP6L or Electro Switch.
FINAL REPORT:
With the actions taken above, CP&L considers this item closed.
i IBMD-WKTW01-OS4
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