ML20077L451
| ML20077L451 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 08/05/1991 |
| From: | Beck G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-13, NUDOCS 9108120247 | |
| Download: ML20077L451 (5) | |
Text
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GL 89-13 PIHLADEll'HIA El,ECTitlC COMI'ANY NUCLEAR GROUP HEADQUARTERS 955-65 CHESTERBROOK HLVD.
WAYNE, PA 19087-5691 (215) 640 6000 NUCLEAR ENGINEERING & SERVICES del %RTMENT August 5, 1991 Docket Nos.
50-352 50-353 License Nos. NPF-39 NPF-85 U.S.
Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555
SUBJECT:
Limerick Generating Station, Units 1 and 2 Generic Letter 89-13, " Service Water Problems Affecting i
Safety - Related Equipment" Implementation of Actions
REFERENCES:
1)
Letter from D.
R.
Helwig, PECo, to USNRC,
" Response to NRC Generic Letter 89-13,
' Service Water System Problems Affecting Safety-Related Equipment',"
dated January 29, 1990 2)
Letter from USNRC to G.
A.
Hunger, PECo,
" Generic Letter 89-13, ' Service Water Problems Affecting Safety-Related Equipment'," dated June 6, 1990
Dear Sir:
The subject Generic Letter 89-13 required licensees, pursuant to 10 CFR 50.54(f), to advise the NRC whether it has established programs to implement Recommendations I-V of the Generic Letter or that the licensee has pursued an equally effective alternative course of action.
Further reporting requirements required that licensees confirm to the NRC that all the recommended actions or their justified alternatives have been implemented within 30 days of such implementation.
Philadelphia Electric Company (PECo) has detailed our program to implement the Generic Letter recommendations or alternatives in Reference 1.
The NRC found this description of the program to satisfy the intent of the Generic Letter and requested that we notify the NRC when the actions specified in our January 29, 1990 letter are implemented, as documented in Reference 2.
This letter is being submitted to satisfy the reporting requirement and the NRC notification request for the Limerick Generating Station (LGS),
I Units 1 and 2, since all actions, except completion of the Residual Heat Removal Service Water (RHRSW) System Design gg 9108120247 910805 1-pDs nDom osoom s:
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U.S. Nuclear Regulatory Commission August 5, 1991 GL 89-13 Page 2 Baseline Docunient (DBD), were. implemented by July 5, 1991.
As specified in our January 9, 1991 letter, the RHRSW System DBD will be completed in-the fourth quarter of 1991.
We intend to notify the NRC within 30 days of completing the RHRSW System DDD.
The Attachment to this letter includes a restatement of each recommended action item along with a summary description of actions or programs taken to implement the item.
If you have any questions, or require additional information, please contact us.
Very truly yours, CW G. J.
Beck
- Manager, Licensing Section Attachment cc:
T. T.
Martin, Administrator, Region I, USNRC T. J.
Kenny, USNRC Senior Resident Inspector, LGS i
f t
I
o ATTACHMENT LIMERICK GENERATION STATION, UNITS 1 AND 2
" SERVICE WATER SYSTEM PROBLEMS AFFECTING SAFETY-RELATED EQUIPMENT" NRC Recommended Action I For open-cycle service water systems, implement and maintain an ongoing program of surveillance and control techniques to significantly reduce the incidence of flow blockage problems as a result of biofouling.
. STATUS The frequency of surveys to identify Asiatic clams in the plant make-up water sources had been increased to semi-annually.
The Fall 1990 survey indicated that the overall presence of Asiatic clams had increased slightly; however, inspections of plant cooling' tower basins and the spray pond have not identified clams.
Preparations are underway to perform a biocide application in the event that the clam populations escalate.- The-chlorination program has been evaluated and a sodium hypochlorite injection skid has been. installed in the Spray Pond Pump House to enable chlorine injection into the Emergency Service Water (ESW) and Residual Heat Removal Service Water (RHRSW) pump wet wells.
The existing test programs-to flush infrequently used cooling-loops and components were evaluated and the ESW system is now flushed with service water or ESW.
This flush is done weekly.
The lay-up practices for ESW system components were evaluated and now, following chlorine injection to the pump wet wells, theisystem is put inte lay-up with the chlorinated water.
These actions were completed by the end of the third refueling outage for Unit 1, December 17, 1990, and the first refueling outage for Unit 2, June 5, 1991.
RecommendedLAction II Conduct a test program to verify the heat _ transfer capability of all safety-related heat exchangers cooled by service water.
The totalLtest program should consist of an initial test program and a periodic retest program.
Both the initial test program and the periodic retest program should include heat exchangers connected to or cooled by one or more-open-cycle systems.
An example of an alternacive action that would be acceptable to the NRC is frequent regular maintenance of a heat exchanger in lieu of testing for degraded performance of the-heat exchanger.
~
Page 2 STATUS An initial test program to verify the heat transfer capabilities of safety related heat exchangers cooled by the ESW System and the RHRSW System was completed on April 14, 1991-for Unit 1, and by July 5, 1991 for Unit 2.
This program was different than the program recommended in Generic Letter 89-13.
These differences are detailed in our January 29, 1990 letter and were found acceptable by the NRC in its letter dated June 6, 1990.
In summary, the major difference is the use of a "most limiting" heat exchanger for test purposes.
The "most limiting" heat exchanger is determined by an engineering analysis which selects the one heat exchanger in each group of similar heat exchangers which is most subject to reduction in heat transfer capability and which can be practically tested.
A periodic retest program is being implemented in accordance with the recommendation for the most limiting heat exchanger.
Recommended Action III Ensure by establishing a routine inspection and maintenance program for open-cycle service water system piping and components that corrosion, erosion, protective coating failure, silting and biofouling cannot degrade the performance of the safety-related systems supplied by service water.
STATUS Revision of the existing Preventive Maintenance (PM) programs to ensure that corrosion, erosion, silting, and biofouling do not degrade the performance of ESW and RHRSW components was completed. prior to start up from the third refueling outage _for Unit-1, December 17, 1990, and the first refueling outage for Unit 2, June 5, 1991.
Protective coating failure was not addressed because the affected piping in the service water systems are not protected with internal coatings.
Recommended Action IV Confirm that the service system will perform its intended function in accordance with the licensing basis for the plant.
Reconstitution of the design basis of the system is not intended.
This confirmation should include a review of the ability to perform required safety functions in the event of failure of a single active component.
To ensure that the as-built system is in accordance with the appropriate licensing basis documentation, this confirmation should include recent (within the past 2 years) system walkdowns.
STATUS As referenced in our January 29, 1990 and January 9, 1991. letters, the Design Baseline Document (DBD) for the ESW System was completed and issued by March 28, 1991.
During the
Page 3 development of this document, a review of design documents such as. calculations, specifications, the Limerick Generating Station (LGS), Units 1 and 2, Updated Final Safety Analysis Report (UFSAR), modification documentation, system drawings and other licensing basis documents was completed and confirmed that the ESW system will perform its intended functions.
In addition, a Safety System Functional Inspection (SSFI) was performed between November 1990 and January 1991.
No significant deficiencies in the ESW system were identified as a result of these activities.
The RHRSW DBD has been started and is scheduled to be completed in the fourth quarter of 1991.
i Recommended Action V Confirm that-maintenance practices, operating and emergency procedures, and training that involves the service water system are adequate to ensure that safety-related equipment cooled by the service water system will function as intended and that operators of this equipment will perform effectively.
This confirmation should include recent (within the past 2 years) reviews of practices, procedures, and training modules.
The intent of this action is to reduce human errors in the operation, repair and maintenance of the service water system.
STATUS The maintenance practices, operating and emergency operating procedures, and training which involve the ESW and the
=RHRSW systems were reviewed and revised to ensure that safety related equipment cooled by these systems will function as intended and that opportunity for human error is minimized.
This action was completed by the end of the third refuel outage for Unit 1, December 17, 1990, and the first refuel outage for Unit l
2, June 5, 1991.
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