ML19259D265
| ML19259D265 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 10/01/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Eric Turner HOUSTON LIGHTING & POWER CO. |
| References | |
| NUDOCS 7910170525 | |
| Download: ML19259D265 (1) | |
Text
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UNITED STATES
- * /c>a atc,"'o, NUCLEAR REGULATORY COMMISSION o
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t/'i REGloN IV 611 RYAN PLAZA DRIVE, SUITE 1000
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ARLINGTON, TEX AS 76012 7
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October 1, 1979 In Reply Refer To:
RIV Docket Nos. 50-498/IE Information Notice No. 79-25 50-499/IE Information Notice No. 79-25 Houston Lighting & Power Company ATTN:
Mr. E. A. Turner, Vice President Power Plant Construction and Technical Services Post Office Box 1/00 Houston, Texas 77001 Gentlemen:
This IE Information Notice la provided as an early notification of a possibly significant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If further NRC evalu: P. ions so indicate, an IE Circular, Bulletin, or NRR Generic Letter will be issued to recommend or request specific licensee actions.
If you have questions regar61ng the matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, J
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Director
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Enclosures:
1.
IE Information Notice No. 79-25 2.
List of IE Information l l g ')
Notices Issued in Last Six Months 7910170 CS
Accession No.:
7908220125 SSINS No.:
6870 U'JITED STATES UCLEAR REGULATORY COMMISSION Ort 1CE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 IE Information Notice 79-25 Date:
October 1, 1979 Page 1 of 2 REACTOR TRIPS AT TURKEY POINT UNITS 3 AND 4
Background
On August 3, Turkey Point Units 3 and 4 tripped operating at full power.
A voltage spike on a secon I protection channel caused Unit 4 to trip during surveillance testing on the reactor protection system. This resulte in a loss of offsite power and subsequent shedding on non-essential loads.
Unit 3 tripped as the result of high coolant pressure caused by a turbine runbeck.
Discussion While performing a periodic test on channel "C" of the T-Average and Delta T Protection Channels, a spurious signal on channel "A" completed a 2 out of 3 sip logic: tripping Unit 4.
This resulted in a loss of offsite power condi-tion for Unit 4.
At this time, Unit 4 start-up tranformer was out of service due to performance of periodic maintenance.
This condition caused the initiation of the emergency diesel generator load sequencer which resulted in the shedding of non-vital loads. Among the non-vital loads shed, were those on Motor Control Center (MCC) "D" which is common to both units.
Since the Rod Position Indication System for both units is powered by the non-vital portion of MCC-D, a turbine runback on Unit 3 was initiated upon loss of rod position indication. This resulted in a reactor trip on high pressurizer pressure. At the time, neither of the two pressurizer spray valves was available.
One was considered inoperable prior to the transient and the other, temporarily powered by the non-vital portion of MCCD, had become unavailable earlier as a consequence of the Unit 4 trip.
A subsequent review disclosed inadequacies in the administrative controls over the correction of operational problems exhibited by spray valve PCV-3-4558.
The original Hagan cont roller for spr--
" '~ - M - -cmd and was placed by another manual cont cont rol circuit and which had been ta control room.
The actual installatio performed under established guideline DUPLICATE DOCUMENT had been issued to ensure consistent operational control of this unusual c Entire document previcusly entered into system under:
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