ML20085F500
| ML20085F500 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/27/1974 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML20085F491 | List: |
| References | |
| RO-UE-1-74, NUDOCS 8308220151 | |
| Download: ML20085F500 (3) | |
Text
r~-
1 O
rs v
G fy l
x n
/
\\ Consumers j
l Power Company
}
s.q
[
I D
VV U
o.n... on.c..: osa wesi u.cn. gen Avenue.. Jackson, Machigan 49201. Area Cod. S17 788-OSSO September 27, 1974 Mr. James G. Keppler, Director Re:
Docket 50-255 Region III License DPR-20 Directorate of Regulatory Operations Palisades Plant - UE-1-Th US Atomic Energy Commission 799 Roosevelt Road Glen Ellyn, IL 60137
Dear Mr. Keppler:
Attached is an Unusual Event Report (UE-1-Th) covering a reactor protective system relay failure. Recent failures of this relay have caused the Palisades Plant Review Committee to reclassify these failures from a Nonreportable Event to an Unusual Event. After review by the Plant Review Committee and the Safety Audit and Review Board, it was concluded that it was safe to return the plant to ser-vice. Additional information and plant records are available at the plant site.
Yours very truly,
%1ph B. Sewell (Signed)
DAB /ds Q ph B. Sewell Nuclear Licensing Administrator 8308220151 741021 PDR ADOCK 05000 S
t TP 3 0 3
,.e.
.... =
l l
I UNUSUAL EVENT REPORT Palisades Plant l
l 1.
Unusual Event: UE-1-Th 2a.
Report Date:
September 27, 1974 2b.
Event Date:
August 30, 1974 (Claselfied as an Unusual Event) 3 Facility: Palisades Plant, Covert, Michigan 4.
Identification of Event:
Reactor Protective System Relays Failure To Open 5
Condition of Event: Plant in Cold Shutacvn 6.
Description of Event: On May 14, 1974 while doing monthly Technical Specification surveillance reactor protective system matrix logic test (MO-3), it was noted that the contacts on Relays AC-1 and AC-2 failed to open when they were de-energized. A review of the mainte-nance history (Item 10) indicated these failures may be attributed I
to operation, without the proper are suppression, prior to October 1, j
1971.
It was decided, after Plant Review Committee (PRC) approval, j
to replace all 24 relays with identical components.
i Twelve relays were replaced as of May 28, 197h with the remaining l
12 avaiting delivery from the manufacturer.
While performing a reactor protective system matrix logic test on August 8, 1974, Relay BC-2 failed to open. Then on August 17, 1974, Relay AD-2 failed and on August 19, 1974, Relay CD-2 failed.
All of these failures were with the older relays and indicated that j ganaric type problem might exist with the originally supplied relays.
The failed relays were removed and a PRC recommendation was sought prior to start-up.
7 Designation of Apparent Cause of Event: The failed relays have been returned to the manufacturer for further investigation. Manufacture, design and/or service condition are considered likely causes of the relay failures.
8.
Analysis of Event: The event was reviewed on August 30, 1974 by the PRC, at which time it was decided to reclassify the item as an Unusual Event because the failures appeared to be a generic problem. This review disclosed that while some of the failures were in a nonfail-safe direction, a minimum of two particular relays would have to fail simultaneously before any one safety function could be defeated.
It was also determined that no failure had occurred until several years after the equipment had been placed in service, indicating that the problem could be related to service life.
\\
. G. ? -
O 0
2
\\
r a
9 Corrective Action: Pursuant to the recommendations of the PRC, the following action was or is being taken:
On August 27, 1974, trip testing of the matrix relays indicated proper operation of the M-coil are suppression network.
On September 3,1974, the PRC recommended that the new relays be placed in the No 3 and No 4 positions and all originally supplied relays removed from the No 1 and No 2 positions (reference FSAR Figure 7-1A), thus, operating on the right side clutch power supplies only.
This mode of operation effectively removed the origi-nally supplied relays from service and is to continue until replacement relays are obtained.
Pursuant to the findings of the Safety Audit and Review Board, the following action is being taken:
Operation with the new relays will be restricted to a period of approximately one year with the relays being tested on a weekly schedule. In addition, the investigation will be continued. It will con-sider alternate designs as well as resolution of the present failure mechanism. A report of this investi-gation is to be presented to the SARB within one year.
If it is determined that changes to the system are re-quired, they will be made and reported in accordance with the requirements of 10 CFR 50.59 10.
Failure Data: The following reactor protective system matrix relay history begins in April 1971 with the first recorded failure and continues to date.
Date Relay Description of Event h-26 AB-2 Control contacts failed to open. Noticed incorrect are suppresssion network.
10- 1-71 Completed are suppression network revision.
5-15-72' BD-2 Control contacts intermittent open.
9-22-72.
BD-h No record of failure mode.
h-15-Th-AD-1 Control contacts failed to close.
5-14-74' AC-1 Control contacts failed to open.
5-14-74' AC-2 Control contacts failed to open.
'8-8-74 BC-2 Control contacts failed to open.
8-17-Th AD Indication contacts failed to open.
8-19-74 CD-2 Indication contacts failed to open.
The relays were manufactured by Adams and Westlake and are _ Type MW 2621-609 df/@W)4/W e
a