ML20127E358
| ML20127E358 | |
| Person / Time | |
|---|---|
| Issue date: | 10/20/1992 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | |
| References | |
| SECY-92-355, NUDOCS 9210280121 | |
| Download: ML20127E358 (6) | |
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POLICY ISSUE SECY-92-355 October 20, 1992 (NEGATIVE CONSENT) g:
The Comeissioners yrom..
Jamas M. Taylor Executive Director for Operations
Subject:
IMPLEMENTING SERVICE WATER SYSTEM OPERATIONAL PERFORMANCE INSPECTIONS (SWSOPIs)
Purnose:
To apprise the Commission of the progress made in developing Service Water System Operational Performance Inspections, and to request Commissior, approval of the staff's intent to perform the inspection at sites with perceived service water system problems, problem plants, and older f acilities.
Commission approval is required based upon Chairmon Carr's memorandum to me dated April 12, 1991, which commented on the five-year plan, and stated that Commission approval will be required before new major generic team inspection programs are undertaken.
Bac ktircund :
The service water system (SWS) typically removes heat from safety-related equipment and reactor decay heat during shutdown operations. An increasing number of service water system (SWS) events in the late 1970's and early 1980's resulted in the issuance of Bulletin 81-03 related to flow blockage by Asiatic clams and mussels. A number of follow-up information notices discussed other fouling and flow blockage concerns.
The above events were evaluated by the Office for Analysis and Evaluation of Operational Data and the Office of Nuclear Regulatorj Research.
These evaluations were published in NUREG-1275, Volume 3, November 1988, " Operating Experience f
Feedback Report - Service Water System Failures and Degradations," and NUREG/CR-5379, Volume 1, June 1989,
" Nuclear Plant Service Water System Aging Degradation Assessment," respectively.
Both evaluations concluded that the majority of the SWS events were due to fouling mechanisms including corrosion and erosion, biofouling,
Contact:
NOTE:
TO BE 11ADE PUBLICLY AVAILABLE Don Norkin, NRR WHEN THE FINAL SRM IS MADE (301) 504-2954 AVAILABLE (J
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foreign material and debris intrusion, cediment deposition, pipe coating-failure, and calcium carbonate depositian.
The second most frequently observed cause was personnel and procedural error.
The AE00 study recognized that loss of the'SWS can' represent a significant contribution to core damage frequency'(CDF).
NUREG1275,Vglume3,estimatedtheCDFtobeintherange of 10'3 to 10' per reactor year based on' plant operating e
experience.
In response to the above indicated operating experience and studies, Generic letter (GL) 89-13, " Service Water System Problems Affecting Safety Related Equipment," provided the following recommended licensee actions:
I.
For open-cycle SWSs, implement and maintain-surveillance and control techniques to significantly reduce the incidence of flow blockage due to biofouling.
11.
Conduct a test program to verify the heat transfer capability of all safety-related heat exchangers cooled by service water.
III.
Establish a routine inspection and maintenance program for open-cycle service water piping and components to ensure that corrosion, erosion, protective coating failure, silting, and biofouling cannot degrade the performance of the. safety-related systems supplied by service water.
IV.
Confirm that the SWS will perform its intended functions in accordance with the licensing basis of the plant, including consideration of the ability to perform required safety functions in the event of failure of a single active component.
V.
Confirm that maintenance practices, operating and emergency procedures, and training that involves the SWS are adequate to ensure that safety-related equipment cooled by the SWS will function as intended and that operators of this equipment will perform-effectively.
Since GL 89-13 a nur%r of plant specific SWS design and-g L
operational concerns have been identified in licensee event--
reports, during inspections, and as result of licensee implementation of GL 89-13.
Due to these continuing L
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The Commissioners problems, the Special Inspection Branch of the Office of Nuclear Reactor Regulation was tasked to develop an inspection to assess the operational performance of the. SWS at operating plants.
Discussion:
The Service Water System Operational Performance Inspection (SWSOPI) was developed to achieve the following objectives:
- to verify that the SWS is capable of meeting thermal and hydraulic design requirements to identify and evaluate SWS design vulnerabilities to assess the SWS opernion, maintenance, surveillance, testing, and associated personnel training
- to assess the unavailability of the SWS due to planned maintenance and surveillance and component failures
- to assess the licensee's planned or u...pleted actions in response to GL 89-13 One pilot inspection is to be conducted in each region since the pilots serve to train the regional inspectors who will conduct the inspections as well as to develop the inspection methodology.
Pilot inspections have been completed at the following sites:
- St. Lucie, Region II (9/91)
- Ginna, Region I (12/91)
- Quad Cities, Region III (3/S2)
- South Texas, Region IV (7/92.
A pilot inspection is planned n a Region V site in January 1993. The spectrum'of findings identified during ti.e pilot inspections ranged from potential operability concerns to less significant issues. The following three examples were identified where licensees had not properly accounted for-single failures of active components:
- The licensee had not evaluated the patential loss of operability due to single failure of a discharge check valve while the SWS was cross-connected.
(Ginna)
- A single failure of a check valve at the interface between ;he normal and emergency SW systems could prevent adequate flow to room coolers during an accident.
(Quad Cities) l
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The Commissioners The technical specification requirement for-twc of four 4
SWS pumps to be operable did not' account-fu single, failure modes-and.their effect-on ensuring required flow -
during the accident recirculation phase.
(Ginna)
Additional findings included:
- Licensee practices allowed SW equipment to be taken out of service for maintenance while. the redundant train was being tested and may not have been able to perform its safety function.
(Ginna)
- Lack of data on flow distribution and fooling conditions in individual emergency core cooling system pump room coolers resulted in failure to ensure adequate flows to each cooler.
(Quad Cities)
- Four of eight residual heat removal (RHR) heat exchanger flow control' valves were not certified as being environmentally qualified although operating instructions called for their use during harsh environment' accident cond,' ions.
(Quad Cities)
- Flow restrictions in Unit 1 RHR heat exchanger room i
coolers were not properly addressed regarding operability and applicability to Unit 2 components.
(Quad Cities)
- The licensee credited the Intake Cooling Water Pump as operable without having adequately tested the pump and its actuation circuitry.
(St. Lucie)
The manual and check valves located on each of the three seismic Category I emergency strainer wash discharge lines perform a safety function, but were not included. in.
the inservice testing program.- (South-Texas)
The planned course of action is to conduct the SWSOPI at most sites.
Fewer significant findings were identified at.
St. Lucie and South Texas, which are newer plants.
In addition, South Texas had performed an effective safety system functional assessment which addressed GL 89-13 issues.
Plants which are perceived to have SWS problems or more general maintenance,- engineering.or technical support problems as well as all plants licensed before 1979 will be inspected. Never plants which have performed effective safety-system functional assessments on the SWS may not be inspected. As a minimum, this inspection will be conducted at 62 percent of the sites, based upon the 1979 criterion and sites already inspected under the pilot program.
Some
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The Commissioners of the additional 38-percent which have problems, as noted above, will be inspected.
The inspection teams will be comprised of a team leader, a mechanical systems design engineer, an operations speciaiist, a maintenance specialist, and a surveillance /
testing specialist. At least one member of the team will have had previous experience with GL 89-13 issues.
For plants with complex electrical distribution system supplies to SWS equipment, an electrical engineer may be added.to_ the team. The NRC resource estimate for-each SWSOPI is 34 staff-weeks, including management participation and-contractors. Of this, 15 staff weeks involve site inspection, which will directly impact. licensees.
The results of the first three pilot inspections were discussed at the Senior Management Meeting in June and a decision was made to proceed with the SWSOPIs as an area of emphasis, subject to Commission approval. The shutdown risk inspection will be discussed at the next Senior _ Management Meeting and this topic or another topic may be proposed for parallel implementation with the SWSOPI.
SWSOPIs would be initiated by the regions in fiscal year 1993 and would take place over about a three year period.
The remaining electrical distribution system functional inspections will be completed in fiscal year 1993 in parallel _with the first SW inspections.
Recommendation _:
Unless advised to the contrary, by the Commission,.within 10 working days from the date of this paper, the staff plans to proceed with the SWSOPIs as an area of emphasis inspection at sites with perceived service water problems, problem plants, and older facilities, amesM.Tahhor secutive Director for Operations
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'SECY NOTE:.In'the absence.of instructions to the-contrary;--SECY will notify the staff on Wednesday, November 4,
- 1992, that tho': Commission,'by negative _ consent, assents:to.
the action proposed in this paper.
DISTRIBUTION:
Commissioners OGC-OCAA OIG OPP REGIONAL OFFICES
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