ML19259D272
| ML19259D272 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 10/01/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Goodwin C PORTLAND GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 7910170539 | |
| Download: ML19259D272 (1) | |
Text
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UNITED STATES yy*
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1990 N. CALIFORNI A DOULEVARD g ' Y --
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SUITE 202, WALNUT CREE K PLAZA U
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WALNUT CREE K, CA'.srORNI A 94596 October 1,1979 Docket No. 50-344 Portland General Electric Company 121 S. W. Salmon Street Portland, Oregon 97204 Attention: Mr. Charles Goodwin, Jr.
Assistant Vice President Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the infcrmation for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular, Bulletin, or Generic Letter will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of t,'Te appropriate NRC Regional Office.
Sincerely, l
mdN-R. H. Engelken Director Enclosures-1.
IE Information Notice 79-25 2.
List of IE Information Notices Issued in Last Six Months cc w/ enclosures:
C. P. Yundt, PGE F. C. Gaidos, PGE 1162 291 7910170 %
Accession flo.: 7908220125 SSlilS ilo. : 6870 UNITED STATES NUCLEAR REGULATORY COMMISSI0fl 0FFICE OF IllSPECTION AllD EtiFORCEMEilT WASHINGT01, D.C.
20555 October 1, 1979 IE Information Notice 79-25 REACTOR TRIPS AT TURKEY POIllT UilITS 3 AtlD 4
Background
On August 3, Turkey Point Units 3 and 4 tripped while operating at full power.
A voltage spike on a second protection channel caused Unit 4 to trip during surveillance testing on the reactor protection system.
This resulted in a loss of offsite power and subsequent shedding of non-essential loads.
Unit 3 tripped as the result of high coolant pressure caused by a turbine runback.
Discussion While performing a periodic test on channel "C" of the T-Average and Delta T Protection Channels, a sourious signal on channel "A" completed a 2 out of 3 trip logic: tripping Unit 4.
This resulted in a loss of offsite power condi-tion for Unit 4.
At this time, the Unit 4 startup transformer 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 avail-able. 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 opera;ional problems exhibited by spray valve PCV-3-4553.
The original Hagan controller for spray valve PCV-3-455B had been disconnected and was replaced by another manual controller which was plugged into the valve control circuit and which had been taped to the top of a console in the main control room. The actual installatio performed under established guideline:
had been issued to ensure consistent i operational control of this unusual ci DUPLICATE DOCUMENT Entire document previously entered into system under:
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