ML18092A348
| ML18092A348 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 08/29/1984 |
| From: | NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | |
| Shared Package | |
| ML18092A347 | List: |
| References | |
| TASK-AE, TASK-T422 AEOD-T422, NUDOCS 8411010444 | |
| Download: ML18092A348 (5) | |
Text
AEOD TECHNICAL REVIEW REPORT*
UNIT:
Salem Unit 1 DOCKET NO.:
50-272 LICENSEE:
Public Service Gas & Electric Co.
NSSS/AE:
Westinghouse/Utility TR REPORT NO.:
AEOD/T422 DATE: August 29, 1984 EVALUATOR/CONTACT:
D. Zukor
SUBJECT:
INOPERABILITY OF SAFETY INJECTION PUMP.AT SALEM 1 EVENT DATE:
OCTOBER 17, 1983
SUMMARY
With the plant at 100% power, a routine surveillance indicated de~raded oil in one of the intennediate SI pumps.
A clogged drain line prevented leak-off water from draining properly and the water backed up into the lube oil reser-voir, thereby contaminating the oil.
No other similar events for SI pumps at PWRs could be found within the last two years of operating data.
Since each SI pump has its own lube oil system, this event does not represent a common mode failure of the intennediate SI system.
A more common method of intro-ducing water into the lube oil systems is by means of lube oil cooler leaks.
This problem has been addressed by the AEOD engineering evaluation entitled "Erosion In Nuclear Power Plants".
r-a411oio444 0400-29 ----~1 i
PDR ADOCK 05000272 I
I s
- This document supports ongoing AEOD and NRC activities and does not represent the position or requirements of the-responsible NRC program office.
l
'... DISCUSSION On October 17, 1983, with the unit at 100% power an equipment operator found the lube oil reservoir for the number 11 safety injection pump contaminated.
The pump was declared inoperable. Subsequent analysis showed the foreign substance to be water.
The licensee found that a drain designed to catch pump* leak-off an.d drain it to the waste hold-up tanks had clogged.
Since the water could not drain, it_
filled up the trough between the pump thrust bearing and the mechanical seal.
When the water exceeded the level of the bearing splash guard, it ran into the lube oil reservoir and degraded the oil. Although both the bearing housing and the bearing surfaces showed signs of corrosion, it was not considered serious enough to prevent acceptable operation of the pump.
The licensee did replace the thrust bearing unit and all of the oil. The lube oil cooler was also replaced as a precaution because Salem has had problems with lube oil coolers leaking.
Routine shift surveillance will now include a visual inspec-tion of this trough to assure that the drain line is clear.
FINDINGS A review of operational data available on safety injection pumps from l/l/82 to 8/10/84 was performed. A similar event was found concerning a centrifugal charging pump at McGuire l in 1982. This type of event does not appear to be frequent, or generic, and in most cases, adequate surveillance procedures detect the problem before the oil becomes contaminated.
Each safety injection pump at Salem l has its own dedicated lube oil system, s.o one clogged drain would not disable this entire SI system.
In general, all safety grade pumps have their own self contained lube oil system.
The data indicated that a more common method of contaminating the lube oil with water comes from leaking lube oil coolers. Although each pump has its own lube oil cooler, the heat transfer medium is the service water system.
Excessive erosion or corrosion caused by this system can result in lube oil cooler leaks.
and contaminated oil. If lube oil cooler leaks are widespread, the possibility exists for the water to contaminate oil in redundant pumps rendering them inoper-able.
The issue has been addressed in an AEOD engineering evaluation entitled 11Erosion in Nuclear Power Plants".
CONCLUSIONS This event does not represent a common cause failure mode, nor does it appear to have widespread generic implications.
AEOD plans no further action as a result of this event.
REFERENCES Licensee Event Report 50-272/83-049.
Licensee Event Report 50-369/82-079.
SCSS Data Base.
AEOD Engineering Eva.luation Report E416 "Erosion In Nuclear Power Plants".
\\
I OFFICE~
SURNAME~
DATE.,
August 29, 1984 MEMORANDUM FOR:
Karl V. Seyfrit, Chief AEOD/T422
~
FROM:
SUBJECT:
Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data Dorothy J. Zukor, Reactor Systems Engineer Reactor Systems 2 Reactor Operations Analysis Branch, AEOD INOPERABILITY OF SAFETY INJECTION PUMP AT SALEM l ON
- OCTOBER 17, 1983 Enclosed please find the Technical Review Report on* the inoperability of one safety injection (SI} pump at Salem 1. A clogged drain line prevented pump leak-off from draining properlv, causing water to enter the pump's lube oil system.
Because each SI pump has its own independent lube oil svstem, the event does not represent a possible common cause failure.
Since no other similar events were found on SI pumps, the event does not appear to have any generic implications.
AEOD plans no further action on this issue. *
Enclosure:
As stated bee w/encl.:
NRC PDR ROAB CF AEOD RF DZukor Wlanning KSeyfrit Tippolito CJHel temes
~~o~o*r Systems Engineer Reactor Systems 2 Reactor Operations Analysis Branch, AEOD
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NRC FORM 318 1101801 NRCM 02"0 OFFICIAL RECORD COPY
- U.S. GPO 1983-400*247
~*-~* --
AEOD TECHNICAL REVIEW REPORT*
UNIT:
Salem Unit l DOCKET NO.:
50-272 LICENSEE:
Public Service Gas & Electric Co.
NSSS/AE:
Westinghouse/Utility TR REPORT NO.:
AEOD/T422 DATE: August 29, 1984 EVALUATOR/CONTACT:
D. Zukor
SUBJECT:
INOPERABILITY OF SAFETY INJECTION PUMP AT SALEM 1 EVENT DATE:
OCTOBER 17, 1983
SUMMARY
With the plant at 100% power, a routine surveillance indicated degraded oil in one of the intennediate SI pumps.
A clogged drain line prevented leak-off water from draining properly and the water backed up into the 1 ube oi 1 reser-voir, thereby contaminating the oil.
No other similar events for SI pumps at PWRs could be found within the last two years of operating data. Since each SI pump has its own lube oil system, this event does not represent a common mode failure of the intennediate SI system. A more common method of intro-ducing water into the lube oil systems is by means of lube oil cooler leaks.
This problem has been addressed by the AEOD engineering evaluation entitled "Erosion I~ Nuclear Power Plants".
- This document supports ongoing AEOD and NRC activities and does not represent the position or requirements of the responsible NRC program office~
.... DISCUSSION On October 17, 1983, with the unit at*1ooi power an equipment operator found the lube oil reservoir for the number 11 safety injection pump contaminated.
The pump was declared inoperable. Subsequent analysis showed the foreign substance to be water.
The licensee found that a drain designed to catch pump leak-off an9 drain it to the waste hold-up tanks had clogged.
Since the water could not drain, it filled up the trough between the pump thrust bearing and the mechanical seal:
When the water exceeded the level of the bearing splash guard, it ran into the lube oil reservoir and degraded the oil. Although both the bearing housing and the bearing surfaces showed signs of corrosion, it was not considered serious enough to prevent acceptable operation of the pump.
The licensee did replace the thrust bearing unit and all of the oil. The lube oil cooler was also replaced as a precaution because Salem has had problems with lube oil coolers leaking. Routine shift surveillance will now include a visual inspec-tion of this trough to assure that the drain line is clear.
FINDINGS A review of operational data available on safety injection pumps from l/1/82 to 8/10/84 was performed. A similar event was found concerning a centrifugal charging pump at McGuire l in 1982. This type of event does not appear to be frequent, or generic, and in most cases, adequate surveillance procedures detect the problem before the oil becomes contaminated.
Each safety injection pump at Salem 1 has its own dedicated lube oil system, so one clogged drain would not disable this entire SI system.
In general, all safety grade pumps have their own self contained lube oil system.
The data indicated that a more common method of contaminating the lube oil with water comes from leaking lube oil coolers. Although each pump has its own lube oil cooler, the heat transfer medium is the service water system.
Excessive erosion or corrosion caused by this system can result in lube oil cooler leaks and contaminated oil. If lube oil cooler leaks are widespread, the possibility exists for the water to contaminate oil in redundant pumps rendering them inoper-able. The issue has been addressed in an AEOD engineering evaluation entitled "Erosion in Nuclear Power Plants".
CONCLUSIONS This event does not represent a common cause failure mode, nor does it appear to have widespread generic implications.
AEOD plans no further action as a result of this event.
REFERENCES Licensee Event Report 50-272/83-049.
Licensee Event Report 50-369/82-079.
SCSS Data Base.
AEOD Engineering Evaluation Report E416 "Erosion In Nuclear Power Plants".