ML20006C671

Responds to Generic Ltr 89-13, Svc Water Sys Problems Affecting Safety-Related Equipment. Plants Have Established Preventive Maint Program for Intake Structure & Routine Treatment of Svc Water Sys W/Biocide to Control Biofouling

ML20006C671
Person / Time
Site:	Peach Bottom, Limerick, 05000000
Issue date:	01/29/1990
From:	Helwig D PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-89-13, NUDOCS 9002080367
Download: ML20006C671 (13)

Text

ec * .c

'10 CFR-50.54(f)

GL 89-13

- PHILADELPHI A ELECTRIC COMPANY NUCLEAR GROUP HEADQUARTERS 955-65 CHESTERBROOK BLVD.-

WAYNE, PA 19087 5691 (215) 640-6650 D AVID R. HELWlO

. vics Passioswv ucci. san ornveces January 29, 1990 Docket Nos. 50r277-50-278 50-352 50-353 License Nos. DPR-44 DPR -

NPF-39 NPF-85 U.S. Nuclear Regulatory. Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

Peach Bottom Atomic Power Station, Units 2 and 3 Limerick Generating Station, Units l~and 2 Response to NRC Generic Letter 89-13, " Service Water System Problems =Affecting Safety-Related-Equipment" Gentlemen:

NRC' Generic Letter (GL) 89-13, " Service Water System Problems:Affecting Safety-Related Equipment," dated July 18, 1989, required licensees to perform recommended actions presented in the-letter or equally effective-alternative = actions to ensure that their service water systems are in compliance and will be maintained in compliance with 10 CFR 50, Appendix A, General. Design Criteria 44, 45,.and 46,-and Appendix'B,-Section XI.- GL 89-13 required a -

response.to be submitted within-180 days-from receipt of the letter advising the NRC whether the-licensee has established programs to

' implement theLrecommendations of the letter or that it has pursued an equally; effective alternative course of action, including schedules of plans-for implementation of the various actions.

Philadelphia Electric Company received GL 89-13 on August 1, 1989. j h.

Our responses for Peach Bottom Atomic Power Station (PBAPS) //

Units 2 and 3 and Limerick Generating Station (LOS) Units 1 and 2, provided in Attachments 1 and 2, describe our current programs and planned actions in response to recommended actions I - V of GL 89-

-13. -j 9002080367 900129 /

3PDR ADOCK 05000277 P PDC n/1[Jloh j

a documsnt Control D3sk January 29, 1990-

.GL.89-13 Page 2 A summary of each recommended action, I-V, of GL 89-13 is

.provided in Attachment 3 to this letter.

A report' confirming that the actions presented in this response have been implemented will be submitted within.30 days of completion for each station. The reports are expected to be submitted in April, 1992 for PBAPS Units 2 and 3, and September, 1991 for LGS Units 1 and 2.

If you have any questions, or require additional information, please contact us.

Very truly yours, i

/

Attachments cc: W. T. Russell, Administrator, Region I, USMRC J. J. Lyash, USNRC Senior Resident Inspector, PBAPS T. J. Kenny, USNRC Senior Resident Inspector, LGS

COMMONWEALTH OF-PENNSYLVANIA :

3

ss.

COUNTY OF CHESTER  :

D. R. Helwig, being first duly sworn, deposes and says:

That'he is Vice President of Philadelphia Electric Company, that he has read the response to Generic Letter No. 89-13, and knows the contents thereof; and that the statements:and matters-set forth therein-are true and correct to the best of his knowledge, information and belief.

l Vice Pres nt Subscribed and sworn to before me this.1f.aday of 74 W 4fl990. 'l b4%W b4 Notary Public-9 .

NOTARIAL SEAL i

. CATHERINE A. MENDEZ. Notary Public Tredyttdn Twp.. Chester County My Commission Expres Sect. 4.1993 i

I

'T

j

. .; s. .

j ATTACHMENT 1 l PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 l RESPONSE TO GENERIC LETTER 89-13,

" SERVICE WATER SYSTEM PROBLEMS AFFECTING SAFETY-RELATED EQUIPMENT"  !

l The Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3,. service ~ water systems consist of the Service Water (SW),

Emergency Service Water (ESW) and High Pressure Service Water (HPSW) I systems. The ESW and HPSW systems are the service water systems I which function to transfer heat from safety-related equipment to an ,

ultimate heat sink. The SW system supplies cooling water required for normal plant operations and has no safety-related function. The SW system removes heat from heat exchangers in the turbine and reactor buildings including the Fuel Pool Cooling and Cleanup system and transfers the heat to the Conowingo Pond. During normal operation, the SW system supplies cooling water to various heat exchangers and coolers associated with the ESW system. In the event of a loss of offsite power, the ESW system supplies cooling water from the Conowingo Pond to safety-related heat exchangers consisting of room unit coolers for the Residual Beat Removal (RHR), Core Spray

-(CS), Reactor Core Isolation Cooling (RCIC), and High Pressure Coolant Injection (HPCI) systems, CS pump motor oil coolers, RHR pump seal coolers, and the emergency diesel generators. The HPSW system supplies cooling water from the conowingo Pond to safety- 1 related RHR heat exchangers. The ESW and HPSW systems are common to Units 2 and 3. In response to a seismic event, resulting in the loss of-the Conowingo Dam, the ESW and HPSW systems are aligned to 4 the Emergency Cooling Tower'to provide safe-shutdown cooling to both units.

The existing programs and planned actions in response to Recommended Actions I-V of Generic Letter (GL) 89-13 are provided below.

Recommended Action I PBAPS will implement programs consistent with those described in Enclosure 1 to GL 89-13, as described below.

PBAPS has an established Preventive Maintenance (PM)

Program for the Intake Structure. The program includes visual inspection of the inner Intake Structure by a diver each refueling outage and removal of accumulated mud and debris as necessary.

, Diver inspections are also performed for the ESW and HPSW Intake L Pump Structure Sump at the same frequency. The sump is sounded on a quarterly basis to determine accumulated mud levels.

l Planned improvements to the Intake Structure PM program l include trending of the inspection findings and review of the outer Intake Structure surveillance for improvements.

PBAPS has an established program for routine treatment of the service water systems with blocide to control biofouling by 1

-,e ,-a -_ - .,u .a - .-s.. - aa - -. ~n..

t

• 2 P

Attachment' 1 Page 2 1

. Asiatic clams. These systems are currently treated once.a year during the most probable spawning periods. A chlorinatica program l has also been established for the SW system and some ESW components to help mitigate other biofouling. The current chlorination program is controlled by compliance with our National Pollutant Discharge Elimination. System (NPDES) permit. Another program in place that I

- addresses potential silting and macrofouling is continuous treatment l of the'ESW systems with dispersant and corrosion inhibitors.

Planned improvements to our current chemical treatment programs will be based upon:

1

1) evaluation of the chemical treatment program for ESW system to develop improvements to increase the chlorination system's reliability, and

2) evaluation.of the need to chemically treat the HPSW system.

In addition, completion of the Unit 2 ESW pipe replacement modification to provide bypass lines at each Emergency Core Cooling System (ECCS) room unit cooler will ensure a constant supply of chemically treated water to piping and coolers when there is no operational requirement for cooling water flow. This improvement was completed on Unit 3 during the last refueling outage.

Most of the redundant and infrequently used cooling loops and components are flushed at test pressures-and flows during <

routine testing. The' existing test programs will be evaluated and revised as necessary to ensure that the infrequently used equipment is adequately flushed to prevent fouling and blockage related problems.-

The current lay-up practices for systems using service water as a source will be evaluated and improved as appropriate to help mitigate corrosion and-fouling.

The activities for developing improvements to existing programs to reduce the incidence of fouling problems, as described above, are expected to be completed prior to startup following the next (eighth) refueling outages for Units 2 and 3, which are currently projected to be April, 1991 and December, 1991 respectively.

Recommended Action II PBAPS will conduct a test program to verify the heat transfer capabilities of safety-related heat exchangers cooled by the ESW and HPSW systems. The total test program will consist of an initial test program and a periodic retest program, with periodic test frequencies based upon previous test results to assure the equipment will perform their intended safety functions during the interval between tests.

i

' Attachment 1 I Page 3 1 The test program will be based upon the program described' l

in Enclosure 2 to GL 89-13 and test techniques developed in conjunction with Electric Power Research Institute (EPRI) and other i utilities. The plans for the test program currently include: i J

a) heat transfer testing of heat exchangers which can be practically tested, b) use of equipment temperature monitoring and trending during -

performance of ECCS pump tests and emergency _ diesel generator testing, and c)- alternative preventive maintenance for certain heat exchangers with maintenance frequency based on hydraulic performance.

The test program will differ from the program described ini  ;

Enclosure 2 to GL 89-13 in that not every safety-related heat exchanger cooled by ESW and HPSW will be subjected to heat transfer testing. .For certain room unit cooler groups subject to the same sources of fouling, such as the CS unit coolers, an engineering analysis will'be performed to determine the one heat exchanger of. '

each similar group which is most subject to reduction in heat-transfer capability and which can be practically tested. These 3 "most limiting" heat exchangers will be tested, and the: test data will then be applied to the hydraulic _ performance of the other similar heat exchangers in the cooling loops to establish heat -

transfer capabilities. This testing method will establish the heat >

transfer capabilities of each safety-related heat exchanger and also ,

maintain plant personnel dose ALARA and reduce the manpower and economic burden of the test program.

The initial test program for Unit 2 is expected to be

. completed ~by April 1992. This twelve (12) month extension to the period requested in GL 89-13 is proposed in order to allow testing of the ESW system components during-the period of lowest cooling water temperatures after the completion of the ESW pipe replacement

' modification work during the eighth refueling outage. Testing during:this period will provide the most useful results because the larger temperature differences on both the air and water side of the L heat exchangers will reduce the significance of instrument l~~

inaccuracies. The initial test program for Unit 3 is expected to be

' completed prior to startup following the eighth refueling outage.

-Recommended Action III PBAPS has established PM programs for the Intake Structure,

-ESW and HPSW system components and the majority of safety-related heat exchangers-cooled by ESW and HPSW. Corrective maintenance is  ;

performed as required.

The existing PM programs at PBAPS will be reviewed and upgraded to include additional inspection and maintenance of system I

i

1 4

Attachment 1 Page 4 .j pipin'g and. components includin 1 heat exchangers,-as necessary,g tothe remainder ensure of the safety-related that corrosion, erosion, j silting, and biofouling do not degrade the required performance of l safety-related systems supplied by the ESW and HPSW systems.

Protective coating failure will not be addressed in the PM programs because the service water system piping is'not protected ]

I with internal coatings.

The program improvements will be established prior to '

startup following the eighth refueling outage for each unit.

Recommended Action IV An independent activity to confirm that the ESW and HPSW systems will perform their intended functions in accordance with the licensing basis for the PBAPS, including a review of single active component failures, will be completed as part of a. Configuration Management design baseline document review of these systems which is scheduled to be completed in late 1990. The task will include:

a) review of original design documents, calculations, specifications, and licensing documents, and ,

b) review of the current Updated Final Safety Analysis Report (UFSAR),. Other licensing documents,_ rodification documentation, and system drawings.

Accessible portions of the ESW and HPSW. systems will be walked down to ensure that the as-built configurations are in accordance with the appropriate licensing basis documentation. However, walkdowns.

are not planned for the portions of the ESW system recently replaced on Unit 2 and Unit 3 because confirmation of the as-built system was performed as part of the modification process.

Recommended Action:V PBAPS will confirm that the maintenance practices, operating and emergency operating procedures, and training which-

involve the ESW and HPSW systems are adequate to ensure that safety-related equipment cooled by these systems will function as intended and that the opportunity for human error is minimized prior to startup following the eighth refueling outage for PBAPS Unit 2.

r ATTACHMENT 2 LIMERICK GENERATING STATION, UNITS 1 AND 2 RESPONSE TO GENERIC LETTER 89-13,  !

" SERVICE WATER SYSTEM PROBLEMS AFFECTING SAFETY-RELATED EQUIPMENT" The Limerick Generating Station (LGS), Units 1 and 2, i service water systems consist of the Service Water (SW), Emergency  !

Service systems.Water (ESW) and Residual Deat Removal Service Water (RHRSW) I The ESW and RHRSW systems are the service water systems which function to transfer heat from safety-related equipment to an ultimate heat sink. The SW system supplies cooling water required for normal plant operation and has no safety-related function. The SW system removes heat from heat exchangers in the turbine, reactor, l

and radwaste enclosures and transfers the heat to the cooling towers. During normal operation, the SW system supplies cooling  !

water to various heat exchangers and coolers associated with the ESW system. In the event of a loss-of-offsite power or loss-of-coolant accident, the ESW system supplies cooling water from the Spray Pond (Ultimate Beat Sink) to safety-related_ heat exchangers consisting of room unit coolers for the Residual Heat Removal (RHR), Core Spray (CS), Reactor Core Isolation Cooling (RCIC), and High Pressure Coolant Injection (HPCI) systems, motor oil and seal coolers for the RHR pumps, control room chillers, and the emergency diesel generators. The ESW system is common to Units 1 and 2 and consists of two (2) independent loops. The RHRSW system supplies cooling 1 I

water from the Spray Pond to the safety-related RBR heat exchangers. i The system is common to Units 1 and 2 and consists of two (2) independent loops, each servicing one RHR heat exchanger in each unit.

The existing programs and planned actions in response to Recommended Actions I-V of Generic Letter (GL) 89-13 are provided below.

Recommended Action I LGS will implement programs consistent with those described in Enclosure 1 to GL 89-13 with the exception of intake structure inspections, as described below.

LGS has an established inspection program for the Spray Pond and cooling tower basins. The Spray Pond and cooling tower basins are currently inspected once each refueling cycle, and accumulated sludge is removed as necessary. This practice of inspection is considered to be as effective as intake structure inspections because these structures provide large settling areas, and are the locations where service water enters plant systems. A planned improvement to the existing inspection practice will be to trend the inspection findings.

LGS currently does not have Asiatic clams in its plant intake vicinity, however, Asiatic clams are present in the source water bodies. The source water bodies are currently surveyed for

• Attachment 2

-Page 2 Asiatic clams annually. We plan to increase the frequency of i

surveys in the general plant vicinity to semi-annuallys The I surveying program will be discontinued when Asiatic clams are identified to be in the plant intake vicinity. A clam biocide treatment program similar to the program currently being implemented at the Peach Bottom Atomic Power Station (PBAPS) is being evaluated for use at LGS when it becomes necessary. The implementation of this program will be contingent upon revision of our National '

Pollutant Discharge Elimination System (NPDES) permit.

l i LGS has an established chlorination program to help i' mitigate biofouling in the nonsafety-related SW system. The program treats some ESW system components due to normal system line-ups during the treatment.

Planned improvements to the chlorination program will be based upon:

1) evaluation of the current method of chlorination and the locations of chemical injection, and ,

}

2) evaluation of changes to systems' operations and line-ups '

during chemical treatment to ensure adequate treatment for l' ESW system components.

In addition, we intend to pursue an increase of the current periods of chemical treatment, while remaining in compliance with our NPDES permit.

Most of the redundant and infrequently used cooling loops and components are flushed at test pressures and flows during routine testing. The existing test programs will be evaluated and revised as necessary to ensure that the infrequently used equipment  ;

is flushed on a routine basis to prevent fouling and blockage '

related problems.

The lay-up practices for ESW system components will be evaluated and improved as appropriate to help mitigate corrosion and ,

fouling. The RERSW heat exchangers are currently laid up with demineralized water when taken out of service. Lay-up practices for

'the remainder of the RHRSW system will be evaluated and improved as necessary. .

The activities for developing improvements to exi7 ting programs to reduce the incidence of fouling problems, as d5 scribed above, are expected to be completed prior to startup fnilowing the next (third) refueling outage for' Unit 1 and the next (first) refueling outage for Unit 2, which are currently projected to be December, 1990 and July, 1991, respectively.

Attachment 2 Page 3 t

Recommended Act3on II LGS will conduct a t7st program to verify the heat transfer capabilities of safety-related heat exchangers cooled by the ESW and MRRSW systems. The total test program will consist of an initial test program and a periodic retest program, with periodic test frequencies based upon previous test results to assure the equipment '

will perform their intended safety functions during the interval between tests.

The test program will be based upon the program described in Enclosure 2 to GL 89-13 and test techniques developed in conjunction with the Electric Power Research Institute (EPRI) and other utilities. The plans for the test program currently includes a) heat transfer testing of heat exchangers which can be  !

practically tested, >

b) use of equipment temperature monitoring and trending during performance of Emergency Core Cooling System (ECCS) pump -

tests and emergency diesel generator tests, and c) alternative preventive maintenance for certain heat exchangers with maintenance frequency based on hydraulic performance.

• The test program will differ from the program described in Enclosure L to GL 89-13 in that not every safety-related heat i exchanger cooled by the ESW and RERSR systems will be subjected to heat transfer testing. For certain room unit cooler groups subject to the same sources of fouling, such as the CS unit coolers, an engineering analysis will be performed to determine the one heat exchanger of each similar oroup which is most subject to reduction in heat transfer capabilit and which can be practically tested.

l These "most limiting" heat exchangers will be wested, and the test  !

data will then be applied to the hydraulic performance of the other i similar heat exchangers in the cooling loops to establish heat transfer capabilities. This testing method will establish the heat .

transfer capabilities of each safety-related heat exchanger and also maintain plant personnel dose ALARA and reduce the manpower and i

economic burden of the test program.

l The initial test program for Unit 1 is expected to be completed within four (4) months following the third refueling outage. This four (4) month extension to the period requested in GL l 89-13 is proposed in order to allow testing of the ESW system components during the next period of lowest cooling water temperatures. Testing during this period will provide the most useful results because the larger temperature differences on both the air and water side of the heat exchangers will reduce the significance of instrument inaccuracies. The initial test program for Unit 2 la expected to be completed within one (1) month following the first refueling outage. This extension is proposed in order to allow for the performance of corrective maintenance and i

Attachment 2  !

Page 4 potential modification activities during the outage prior to establishing the baseline tests. ,

Recommended Action III LGS has established PM programs for the cooling tower [

basin, ESW and RHRSW system components including the ESW side of the i diesel generator heat exchangers and the RHR pump seal and motor oil  ;

coolers. Corrective maintenance is performed as required.

1 The existing PM programs at LGS will be reviewed and upgraded to include additional PM tasks, as necessary, for 1

inspection and maintenance of system components and piping to ensure i that corrosion, erosion, silting, and biofouling do not degrade the J required performance of safety-related systems supplied by the ESW and RHRSW systems.

Protective coating failure will not be addressed in the PM programs because the service water system piping is not protected with internal coatings. ,

The program improvements will be establiohed prior to startup following the third refueling outage for Unit 1 and the

, first refueling outage for Unit 2.

Recommended Action IV An independent activity to confirm that the ESW and RHRSW  !

systems will perform their intended functions in accordance with the

' licensing basis for LGS, including a review of single active component failures, will be completed as part of a Configuration Management design baseline document review of these systems which is scheduled to be completed in late 1990. The task will includes i a) review of original design documents, calculations, specifications, and licensing documents, and b) review of the Final Safety Analysis Report (PSAR), other licensing documents, modification documentation and system drawings. '

System walkdowns and performance testing were recently ,

completed for the ESW and RRRSW systems during the preoperational test programs conducted in 1984 for Unit 1 and 1988 for Unit 2. The programs included reviews of system design and as-built configuration and testing to verify the systems' capability to perform in accordance with their licensing basis. Additional walkdowns will be performed to resolve discrepancies identified during the design baseline document review.

The LGS modification process, which was implemented prior to the startup of Unit 1, ensures that any design changes made to

[

Attachment 2 -

Page 5  ;

i.

safety-related equipment and systems are subjected to a 10 CPR 50.59 evaluation and a review of the Technical Specifications and the i PSAR. Administrative controls are also established to ensure that maintenance, troubleshooting, testing, and modification activities are performed in a manner which does not degrade plant design. Each activity is governed by a specific plant procedure.

Philadelphia Electric Company (PECo) plans to conduct a  :

Safety System Functional Inspection (SSF1) of the LGS ESW system in

• 1990.

Recommended Action V LCS will confirm that the maintenance practices, operating and emergency operating procedures, and training which involve the  ;

ESW and RHRSW systems are adequate to ensure that safety-related 1 equipment cooled by these systems will function as intended and that the opportunity for human error is minimize <3 prior to startup following the third refueling outage for LCL Unit 1.

b l

l l

l

.. i .

)

ATTACHMENT 3 I i

l

SUMMARY

OF RECOMMENDED ACTIONS j I-V OF GENERIC LETTER 89-13,  !

" SERVICE WATER SYSTEM PROBLEMS AFFECTING j SAFETY-RELATED BQUIPMENT" i I. For open-cycle service water systems, implement and I maintain an ongoing program of surveillance and control  :

techniques to significantly reduce the incidence of flow  :

blockage problems as a result of biofouling.

II. Conduct a test program to verify the heat transfer j capability of all safety-related heat exchangers cooled by service water. The total test program should consist of an )

initial test program and a periodic retest program. Both I the initial test program and periodic retest program should i include heat exchangers connected to or cooled by one or  ;

more open-cycle systems. An example of an alternative '

action that would be acceptable to the NRC la frequent regular maintenance of a heat exchanger in lieu of testing for degraded performance of the heat exchanger. j III. Ensure by establishing a routine inspection and maintenance l 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 suppled by '

service water.

IV. Confirm that the service water system will perform its '

intended function in accordance with the licensing basis 'I 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 e appropriate licensing basis documentation, this  ;

confirmation should include recent (within the past 2 years) system walkdown inspections.

+

, V. Confirm that maintenance practices, operating and emergency procedures, and training that involves the service water

• l system are adequate to ensure that safety-related equipment t t

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. ,

l f

.__ - . , _ . ~ < - < . -