ML19254C726
| ML19254C726 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 10/02/1979 |
| From: | Pappas H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 7910170267 | |
| Download: ML19254C726 (2) | |
Text
/ bl3 f0f Addressees - Memorandum dated October 2, 1979 IE Fil_s MPA/DTS Central Files Reproduction Unit NRC 20b 1157 037 l,.
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UNITED STATES NUCLEAR REGULATORY COMMISSION o
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GLEN ELLYN. ILLINOIS 60137 BCT 2 1979 "EMORANLUM FO those on Atta'.hed List FROM:
Helen Pappas, Chic., Administrative Branch
SUBJECT:
IE INFORMATION NOTICE NO. 79-25 The attached IE Information Notice No. 79-25 titled " Reactor Trips at Turkey Point Units 2 and 3" was sent to the following i!censees on Octcoer 1, 1979, for information.
American Electric Power Service Corporation Indiana and Michigan Power Company D. C. Cook 1, I (50-315, 50-316)
Cincinnati Gas & Electric Company Zimmer (50-358)
Cleveland Electric Illuminating Company Perry 1, 2 (50-440, 50-441)
Commonwealth Edison Company Braidwood 1, 2 (50-456, 50-457)
Byron 1, 2 (50-454, 50-455)
Dresden 1, 2, 3 (50-10, 50-237, 50-249)
La Salle 1, 2 (50-373, 50-374)
Quad-Cities 1, 2 (50-254, 50-265)
Zion 1, 2 (50-295, 50-304)
Consumers Power Company Rock Point (50-155)
Bit Midland 1, 2 (50-329, 50-330)
Palisades (50-255)
Dairyland Power Cooperative LACBWR (50-499)
Detroit Edison Company Fermi 2 (50-341)
Illinois Powe-Company Clinton 1, 2 (50-461, 50-462) 1157 138
007 3 PT Those on Attached List Iowa Electric Light & Power Company Duane Arnold (50-331)
Northern Indiana Public Service Company Bailly (f0-367)
Northern Stat s Power Company Monticello (30-263)
Prairie Island 1, 2 (50-282, 50-306)
The Ohio Edison Company Erie 1, 2,(50-580, 50-581)
Public Service of Indiana Marble Hill 1, 2 (50-546, 50-547)
Toledo Edison Company Davis-Besse 1 (50-346)
Union Electric Company Callaway 1, 2 (50-483, 50-486)
Wisconsin Electric Power Company Point Beach 1, 2 (50-266, 50-301)
Wisconsin Public Service Corporation Kewaunee (50-305)
Helen Pappas, Chief Administrative Branch
Attachment:
IE Information Notice No. 79-15 I157 ]39 RII P
as/sr 10/1/79
Accession No.: 7908220125 SSINS No.:
68?0 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 October 1, 1979 IE Information Notice 79-25 REACT 0P TRIPS AT TURKEY POINT UNITS 3 AND 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 subsevent 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 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, 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 operational problems exhibited by spray valve PCV-3-455B.
The original Hagan controller for spray valve PCV-3-455B had been disconnected and was replaced by another manual controller which was pluggad 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 performed under established guidelines.
Additionally, no temporary procedure had been issued to ensure consistant understanding between shifts of the operational control of this unusual ca-aaaa+ ~ad a""H an f
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