ML19254E567
| ML19254E567 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 10/01/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Cavanaugh W ARKANSAS POWER & LIGHT CO. |
| References | |
| NUDOCS 7911010486 | |
| Download: ML19254E567 (1) | |
Text
CENTRAL FILES PDR:HQ UNITED STATES PR
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u NUCLE AR REGULATORY COMMISSION
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$ i 4 l 611 RYAN PLAZA DRIVE, SUITE 1000 o
E ARl.INGToN, TEXAS 76012 5-Y [.k '[
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October 1, 1979 Docket Nos.
50-313 50-368 Arkansas Power and Light Company ATTN:
Mr. William Cavanaugh III Vice President of Generation and Construction P. O. Box 551 Little Rock, Arkansas 72203 Gentlemen:
This IE Information Notice is 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 responce is requested at this time.
If further NRC evaluations so indicate, an IE Circular, Bulletin, or NRR Generic Letter will be issued to recommend or request specific licensee actions.
If you have questions regarding the matter, please contact the Director of the appropriate NRC Regional Office.
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Sincerely,
, f.,,
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TN;jg.Y' k
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Karl V. Seyfrit 'j.,
Director
Enclosures:
1.
IE Information Notice No. 79-25 2.
List of IE Information
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Notices Issued in Last Six Months cc:
James 2. O'llanlon, Plant Manager Arkansas Nucleat One P. O. Box 608 Russellville, Arkansas 72801 s
7911010 98f.
Accession No.:
7308220125 SSINS No.: 6870 UNITED STATES NUCLEAR REGULATORY COMMISSION
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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 runbacs.
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 initiation of the emergency diesel generator load sequencer which resulted in the shedding of non-vital loads. Among the non-vital loads shed, werr 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. Ac 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, hed 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-3-455B.
The original Hagan controller for spray valve PCV-3-455B had bee.n disconnected and was placed by another manual contro-- ^' '
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control circuit and which had been tape control room. The actual installation performed under established guidelines.
DUPLICATE DOCUBENT had been issued to ensure consistent un operational control of this unusual com Entire doctrnent previously entered into system under:
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a No. of pages:
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