ML19259D269
| ML19259D269 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 10/01/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Aswell D LOUISIANA POWER & LIGHT CO. |
| References | |
| NUDOCS 7910170531 | |
| Download: ML19259D269 (1) | |
Text
/ SO UNITED STATES
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NUCLEAR REGULATORY COMMISSION e
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'[/]f +,i h 611 RYAN PLAZA DRIVE. SUITE 1000 Y I
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ARLINGTON, TEXAS 7G012
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October 1, 1979 In Reply Refer To:
RIV Docket No.
50-382/IE Information Notice No. 79-25 Louisiana Power and Light Co.
ATTN:
Mr. D. L. Aswell Vice President of Power Production 142 Delaronde Street New Orleans, Louisiana 70174 Gentlemen:
This IE Information Notice is pron ded as an er.rly 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 ti.is time.
If further TRC evaluations so indicate, an IE Circular, Bulletin, or I:RR Generic Letter will be issuud to recommend or request specific licensee actions.
If you have questions regarding the matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely,
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,,. ; p -;.. m Kar1 V. Seyfrit
,j Director
Enclosures:
1.
IE Information Notice No. 79-25 2.
List of IE Information Notices Issued in Last Six Months
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7910170 73
Accession No.:
7908220125 SSINS No.:
6870 UNITED STATES NUCLEAR REGULATORY COT!ISSION OFFICE 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 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 on 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 spurious 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, Unit 4 start-up tranformer was out of service due to performance of periodic maintenance.
This condition caused the initiati m of the emergency diesel generator load sequencer which resulted in the shedding of non-vital loads. Among the non-vital loads shed, were these on flotor Control Center (f!CC) "D" which is common to both units.
Since the Rod Position Indication System for both units is powered by the non-vital portion of ?!CC-D, a turbine runback on Unit 3 was initiated upon loss of rod position indication.
This resulted in a reactor trip on high pressurizer prec,tre.
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 t!CCD, had become unavailable earlier as a consequence of the Unit 4 trip.
A cubsequent review disclosed inadequacies in the administrative controls over the correction of operational problems exhibited by spray valve PCV-3-455B.
The original Hagan controller for spray valve PCV-3-455f; had been diso nnected and was placed by another manual cont control circuit and which had been ta control room.
The actual i ns tal la t io:
performed under established guideline-DUPLICATE DOCUMENT had been issued to ensure consistent i operational control of this unusual c.
Entire document previously entered into system under:
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