ML17053B086
| ML17053B086 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 10/01/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Rhode G NIAGARA MOHAWK POWER CORP. |
| References | |
| NUDOCS 7910160537 | |
| Download: ML17053B086 (10) | |
Text
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Docket No. 50-410 UNITED STATES NUCL AR REGULATORY COMMISSION REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA19406
<<Ti tSSS Niagara Mohawk Power Corporation ATTN:
Mr.
G.
K.
Rhode Vice President System Project Management 300 Erie Boulevard, West
- Syracuse, New York 13202 Gentlemen:
This 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 response 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.
Sincerely, Director
Enclosures:
1.
IE Information Notice No. 79-25 2.
List of IE Information Notices Issued in the Last Six Months cc w/encls:
Eugene B. Thomas, Jr.,
Esquire
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ENCLOSURE 1 Accession No.:
7908220125 SSINS No.:
6870 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT MASHINGTON, D.C.
20555.
REACTOR TRIPS AT TURKEY POINT UNITS 3 AND 4
Background
IE Information Notice 79-25 Date:
October 1, 1979 Page
- j. of 2 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 Mhile 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'ffsite 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 MCC-D, 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-3-455B.
The original Hagan controller for spray valve PCV-3-455B had been disconnected.
It 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 installation of the manual controller was not per-formed under established guidelines.
Additionally, no temporary procedure had been issued to ensure consistent understanding between shifts of the operational control of this unusual component configuration.
Enclosure 1
IE Information Notice No. 79-25 Date:
October 1, 1979 Page 2 of 2 Thus, failure to establish guidelines and procedures resulted in unnecessary challenges to the reactor protection system.
The subsequent transient resulted in needless thermal stress cycles on the reactor coolant system and its compo-nents.
If plant procedures had been followed, or if the Rod Position Indica-tion System had been a vital load, this transient would have been prevented.
All holders of operating licenses or construction permits should ensure that temporary procedures for plant changes and modifications are established and followed as required.
ENCLOSURE 2 IE Information Notice No. 79-25 Date:
October 1, 1979 Page 1 Qf 2 LISTING OF IE INFORMATION NOTICES ISSUED IN THE LAST SIX MONTHS 79-10 Nonconforming Pipe Support Struts Information Subject Notice No.
Date Issued 4/16/79 Issued to All power reactor facilities with a CP 79-11 79-12 79-13 79-14 79-15 79-16 79-17 79-18 Lower Reactor Vessel Head Insulation Support Problem Attempted Damage to New Fuel Assemblies Indication of Low Mater Level in the Oyster Creek Reactor Safety Classification of Electrical Cable Support Systems Deficient Procedures Nuclear Incident at Three Mile Island Source Holder Assembly Damage from Misfit Between Assembly and Reactor Upper Grid Plate Skylab Reentry 5/7/79 5/11/79 5/29/79 6/11/79 6/7/79 6/22/79 6/20/79 7/5/79 All power reactor facilities with an OL or CP All Fuel Facilities, Research
- Reactors, and Power Reactors with an OL or CP All power reactor facilities with an OL or CP All applicants for, and holders of a power reactor CP All power reactor facilities with an OL or CP All research and test reactors with an OL All holders of reactor OLs and Cps All holders of reactor OLs
Enclosure 2
IE Information Notice No. 79-25 Date:
October 1, 1979 Page 2 of 2 LISTING OF IE INFORMATION NOTICES ISSUED IN 1979 Information Subject Notice No.
Date Issued To Issued 79-19 79-20 79-20 (Revision No. 1) 79-21 79-22 79-23 79-24 Pipe Cracks in Stagnant Borated Water Systems at PWR Plants NRC Enforcement Policy-NRC Licensed Individuals Same Title as 79-20 Transportation and Com-mercial Burial of Radio-active Material qualification of Control Systems Emergency Diesel Generator Lube Oil Coolers Overpressurization of Con-tainment of a PWR Plant After a Main Steam Line Break 7/17/79 All power reactor facilities with an OL or CP 8/14/79 All Holders of Reactor OLs and CPs and Production Licensees with Licensed Operators 9/7/79 Same as 79-20 9/7/79 All power and research reactors with OLs 9/14/79 All power reactor faci-lities with an OL or CP 9/26/79 All power reactor faci-lities with an OL or CP 10/1/79 All power reactor faci-lities with an OL or CP
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