ML18052B372
| ML18052B372 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 10/30/1987 |
| From: | Burgess B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Norelius C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8711160136 | |
| Download: ML18052B372 (6) | |
Text
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October 30, 1987 MEMORANDUM FOR:
Charles E Norelius, Director, Division of Reactor Safety THRU:
W. G. Guldemond, Chief, Reactor Projects Branch 2 FROM:
Bruce L. Burgess, Chief, Reactor Projects Section 2A
SUBJECT:
PALISADES STATUS REPORT FOR THE PERIOD OCTOBER 10-24, 1987 Enclosed is the Palisades biweekly status report for the period covering October 10-24, 1987.
Two Resident Inspectors monitored licensee activities at the plant during this report period.
Status reports of this type are intended to provide NRC management and the public with an overview of plant activities and NRC inspection activities.
Subsequent monthly inspection reports will address many of these topics in more detail.
Enclosure:
Palisades Status Report cc w/enclosure:
Mr. Kenneth W. Berry, Director Nuclear Licensing David P. Hoffman, General Manager DCD/DCB (RIDS)
Licensing Fee Management Branch Resident Inspector, RIII Ronald Callen, Michigan Public Service Commission Michigan Department of Public Health S7111b00013bcu ~;A~55 PDR A
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~d Original Signed by B. L. Burgess Bruce L. Burgess, Chief Reactor Projects Section 2A RIII
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ENCLOSURE PALISADES STATUS REPORT FOR THE PERIOD OCT.OBER 10-24, 1987
- 1.
Plant Status As of 8:00-a.m. on October 23, 1987, Palisades was in cold shutdown, drained to the mid-loop condition with the primary coolant system (PCS) vented. PCS temperature was 86 degrees F and shutdown cooling was in operation.
- 2.
Facility Operations Summary The facility has been shutdown since October 1, 1987 when the plant was taken off line for the planned maintenance outage.
The plant is currently ahead of a scheduled November 13 on-line date.
Specific situations of interest are identified below.
- 3.
Items of Special Interest Loss of Shutdown Cooling In order to replace the leaking drain valves on the four inte-rmediate Primary Coolant System (PCS) cold legs, the plant was drained to a level of 617 feet, eight inches.
At this level the shutdown cooling (SOC) system is provided with adequate net positive suction head (NPSH) for the pump, but due to the vortexing phenomena which can lead to a loss of pump suction, operator attention is necessary to maintain proper SOC flows and pump discharge pressures.
The attached drawings depic~ the PCS layout and elevations.
(Note the ledge created by the Primary Coolant Pump (PCP) bowl to PCS loop transition piping, permitting the intermediate cold legs to be drained for maintenance.)
At 6:37 p.~. on October 15, 1987, operators stopped the operating SOC pump in response to SOC low flow alarms and indications of fluctuations in discharge pressure.
The operators then noticed one of the four loop isolation valves for SOC (M0-3008) cycling open and closed, causing the flow variations and pump cavitation.
Immediate corrective action was taken by opening the valve breaker while the valve was in the closed _
position.
Approximately 29 minutes later the pump was restarted and the PCS was refilled (7:06 p.m.).. Subsequent licensee investigation and review of this event determined that PCS water had intermittently overflowed the PCP ledge and ran out the PCS cold leg drain valves (open although isolable) for about 15 minutes due to valve cycling induced flow and level surges.
Approximately four inches of water (1,000 gallons) was required to refill the PCS.
Primary plant temperature increased approximately 37 degrees F (92 TO 129 degrees) during the time (26 minutes) the SOC pump was off.
The c_ause of the valve cycling was determined to be incorrectly placed jumpers for MOVATS valve testing. The incorrectly placed jumpers were removed at about 7:05 p.m..
All MOVATS work was suspended, and a review of the work was performed.
It was determined that an electrical drawing was read incorrectly by a contract electrical engineer, resulting in the placement of the jumpers on the wrong valve (M0-3008 vs M0-3062).
No verification or second level review of the terminal selection was being performed.
Verification of correct placement was being performed as required by the licensee's work procedures.
All remaining jumpers installed for MOVATS testing were removed.
After management review, testing was resumed with operators in control of the valves and without the use of jumpers.
An alert was declared under the emergency plan at 7:49 p.m. for that period when the operators did not have the control of the SOC system due to the cycling valve.
The licensee is planning additional corrective actions to deal with the issue of second level technical review and has also requested an INPO assist visit.
Plant management convened a Management Review Board and determined that broader generic issues need to be addressed including:
formalized verification of important functions such as preparation of tagging orders and certain* engineering processes; and procedural and hardware related human factors issues.
This event was reviewed.during a a recently completed 11 in process" maintenance team inspection which determined that greater control of licensee contractors is needed.
The *Resident Inspectors and the region will follow the licensee's corrective actions regarding this event.
Outage Activities The scheduled 45 day maintenance outage is progressing ahead of a scheduled*
November 13, 1987 on line date; Emergent work is being scheduled and has not impacted the critical path work.
NRC inspection of the outage activities i~cluded review of local leak rate testing of containment isolation valves.
Of the 65,200 seem leakage allowed by the Technical Specifications, the total as-found leakage was 31,889 seem.
Additionally, the Limitorque valve operator testing, valve rebuilding and retesting was inspected. The. scope of work, licensee involvement, and contractor support of this project goes considerably beyond the scope of the IEB 85-03
. requirements and, although some control problems were identified, represents an excellent effort to improve the overall condition of valves at Palisades.
Resident review of the low temperature over-pressure protection system continued and determined that the licensee is addressing the concerns expressed in report 255/87024 by re-analysis, setpoint changes and changes to the license requirements.
Testing of the steam generator snubbers was also observed.
One of the three selected for testing failed due to weld porosity that was evidenced by fluid leakage.
This snubber ~as repaired and retested satisfactorily.
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Electrohydraulic Control System As a result of a series of electrohydraulic control (EHC) system ruptures, the most recent on August 17, 1987, the licensee initiated a series of corrective actions.
Prior to the October, 1987. maintenance outage, the supply tubing to the turbine control valves was redesigned including welded fittings, revised supports, and flexible hose for the connection to the valvei where previous vibration induced failures have been experienced.
Westinghouse was also contracted to perform detailed monitoring of the turbine EHC system and other components which may be causing the vibration.
As a result of this diagnostic evaluation, the licensee learned that the vibration of the number four governor valve lines occurred at the natural frequency for the length and size of tubing.
The redesigned tubing and improved bracing will be monitored on plant startup to verify that this contributor has *been eliminated.
Westinghouse also determined that worn valve components were likely causing the vibration.
In response to this finding, the licensee rebuilt the number four governor valve.
The diagnostics also determined that the electronic turbine control system was inducing a harmonic of the failed tubing's frequency.
To eliminate this source, the impulse pressure iransducer will be replaced and a band-pass filter will be installed.
Additional testing will be conducted during unit startup to verify the success of these changes.
Finally, the licensee is confident that the installation of the flexible hoses will allow some operating margin to permit the scheduling of repairs or replacement of components which exhibit or induce vibration during an operating cycle.
The dedicated effort and resources expended in resolving this recurring problem is exemplary of the "new attitude" Palisades is striving toward.
- 4.
Changes to Period of Status Reporting This is the fifth of the biweekly status reports for Palisades, made in response to the directions of the T. E. Murley memorandum dated August 3, 1987.
- 5.
NRC Staff Activities During the Period Two NRC resident inspectors monitored plant operating activities between October 9 and October 23, 1987, including correctiv~ actions for equipment problems and followup on other issues.
The details of these activities can be found in Inspection Report 255/87025(DRP)~ The inspection staff at Palisades during the report period consisted of the fo 11 owing:
Eric R. Swanson N. R. Williams N. J. Timmer Senior Resident Inspector Resident Inspector, Big Rock Point (10/20-23/87)
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