ML20006B557

Forwards Response to Generic Ltr 89-13, Svc Water Sys Problems Affecting Safety-Related Equipment. Procedures in Place for Underwater Insp of Intake Structures in Lake as Well as on-shore Pump Houses Annually

ML20006B557
Person / Time
Site:	Perry
Issue date:	01/26/1990
From:	Kaplan A CLEVELAND ELECTRIC ILLUMINATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-89-13, PY-CEI-NRR-1121, NUDOCS 9002050067
Download: ML20006B557 (8)

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t' THE CLEVELAND. ELECTRIC ILLUMINATING l COMPANY-

. P.O. BOX 97, JB PERRY OHIO 44001 5 TELEPHONE . (216) 250w3737. e. . ADDRESS 10 CENTER ROAD .

M +* FROM CLEVELAND: 479 1200 3 TELEX: 241599-ANSWERBACK: CEIPRYO Al Kaplan' Serving The Best location in the Nation PERRY NUCLEAR POWER PLANT -

January 26, 1990' PT-CEI/NRR-1121 73 U.S., Nuclear Regulatory Commission

! :' ' = Document Control Desk

= Washington D.C. 20555

, Perry Nuclear Power Plant

?~ Docket No. 50-440 li % PNPP Response to Generic Letter 89-13 I " Service Water System Problems Affecting Safety-Related Equipment" Dear. Sir ls c . . .

L The' subject letter requested The Cleveland. Electric Illuminating. Company-(CEI)

L .to' evaluate safety-related' plant systems utilizing Lake Erie water;in an open cycle configuration. -Specific evaluations in each requested area are attached: (1). control of biofouling, (2) trending of heat exchanger  ;

performance, (3) periodic inspection for biological.or water quality related 7 h

systems degradations, (4) design review for' single failure integrity and  ;

_as-built configuration control, and (5) adequacy of maintenance practices,  ;

operating procedures-and training.

.Dur commitments.to implement. requested programs and. evaluations are provided, o l,~ within our attached response to each concern.-.0ur final implementation letter' , .,

? confirming that all initial' tests /activie.ies:have been completed and'that- 9

. continuing programs have been established will be submitted following the ,

requested-evaluation of.3 heat' exchanger performance tests. The. initial c ,

f raquency for these performance tests will be at each refueling out' age,

'therefore, the-schedule for our final confirmation letter is estimated to be the fourth quarter of 1993~. .

,1f you-have any questions, please feel free to call. J q

Very truly yours, ,

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'.' Al Kaplan d 9002050067 900126 Vice President PDR ADOCK 05000440 Nuclear Group p . PDC i l jj AK'njc i l Il cc: NRC Region III, Regional Administrator t.

P. Hiland T. Colburu

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• PY-CEI/NRR-ll21 L ,

Page 1 of 7

't CEI RESPONSE TO GL 89-13 RECOMMENDED ACTIONS I. "For open-cycle service water systems, implement and maintain an ongoing program of surveillance and control techniques to significantly reduce the .

1 incidence'of flow blockage problems as a result of biofouling. Initial activities should be completed before plant startup following the first -

refueling outage beginning 9 months or more after the date of this letter.-

All activities should be documented and all relevant documentation should '

be retained in appropriate plant records."

At PNPP, the safety related open cycle cooling water system to.which this Generic Letter response is directly applicable is the Emergency Service Vater (ESV) System. This is the system which serves "to transfer heat .t '

from structures, systems and components important to safety to an ultimate heat sink" (Lake Erie). In response to staff concerns with other safety ,

significant systems using rav vater as a source, the fire protection system (which shares the ESV pump bay as a water source) is also discussed '

in this letter. For PNPP, the "first refueling outage beginning 9 months or more after the date of this [ Generic] letter" is our 2nd refuel outage, .i scheduled to begin in September 1990. -

Enclosure 1 to Generic Letter 89-13 describes recommended programs to be used to address Action Item I. Four techniques are described; two for surveillance activities and two for control activities. The techniques to be used at a plant depend on whether macroscopic biological fouling. , ,

organisms (mussels or clams) have been detected at the facility. At PNPP, i Asiatic Clams (Corbicula) have not yet been detected (two clams were found in June 1987 at CEI's nearby Eastlake Plant, with no subsequent occurrences found at Eastlake or PNPP), but zebra mussels have been -

lj ider.tified at PNPP. Based on this history, it was decided to discuss-all.

p four of the techniques (Surveillances A and D, Controls B and C) in

[ response to this Generic Letter l'

A. "The intake structure should be visually inspected, once per refueling cycle, for macroscopic biological fouling organisms (for '

example, ... Asiatic class at freshwater plants), sediment, and l' corrosion. Inspections should be performed either by scuba divers or I by devatering the intake structure or by other comparable methods. 3 Any fouling accumulations should be removed."

Response

Procedures are in place for underwater inspection of intake structures in the lake as well as on-shore pumphouses annually. ~

Eadiment buildup is removed from the ESV pump bays and forebay annually if the system engineer determines that system function could be umpaired over the following inspection interval. A vater treatment program is being developed to minimize accumulation of mussels and clams in pump bays, pumps and downstream system  ;

components. If mussels or clams accumulate in sufficient numbers on any inspected surface to impair pump performance, they vill be physically removed. More limited accumulations that do not degrade pump performance vill be left in place. At the present time, no operational problems have resulted from mussel or clam shell accumulation.

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• PY-CEI/NRR-1121 L Page 2 of'7 B. "The service water system should be continuously (for example, during spawning) chlorinated (or equally effectively treated with another

. biocide) whenever the potential for macroscopic biological fouling exists (for example, ... Asiatic clams at freshwater plants).

Chlorination or equally effective treatment-is included for freshwater plants without class because it can help prevent microbiologically influenced corrosion. Bovever, the chlorination (or equally effective) treatment need not be.as stringent for plants where the potential for macroscopic biological fouling species does not exist compared to those plants where it does. Precautions should be taken to obey Federal, State, and local environmental regulations regarding the use of biocides."

Responset PNPP has an ESV chlorination system that operates intermittently during time periods when the potential for a macroscopic biological fouling species exists. CEI is presently evaluating and may test several alternative blocide treatments to determine their relative effectiveness in eliminating Zebra mussels and Asiatic clams-from safety-related' plant systems, in compliance with federal, state and:

local environmental restrictions. The chosen chemical treatment.

system vill be placed into operation before the heavy entrainment period for Zebra mussels in the summer of 1990. The injection mode selected.may be intermittent or continuous.

C. -" Redundant and infrequently used cooling loops should be flushed and flow' tested periodically at the maximum design flow to ensure that they are not fouled or clogged. Other components in the service water system should be tested on a regular schedule to ensure that they are not fouled or clogged. Service water cooling loops should be: filled with chlorinated or equivalently treated ~ vater before layup. Systems:that use raw service water as a source, such as some fire protection systems, should also-be chlorinated or equally effectively treated before layup to help prevent microbiological 1y influenced corrosion. Precautions should be taken to obey Federal, State, and local environmental regulations regarding the use of biocides."

Response

Procedures are in place to flow test all ESV vater-to-vater heat exchanger flow paths quarterly-at design flow rate to record pressure

, drops, and to test ESV pumps quarterly. Design flow rate through each heat exchanger is obtained by throttling the heat exchanger manual discharge valve (normally valve adjustment is not necessary).

Each fire main loop is flov tested and discharge pressure trended every 3 years, and annually hydrants are flushed to verify that no rust is apparent while flow testing. The adequacy of water treatment for the ESV and fire protection systems vill be confirmed for all modes of operation in conjunction with the ESV treatment system development described in (B) above. In addition, since the fire protection system is maintained greater than 100 psig by a jockey a

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PY-CEI/NRR-ll21 L'

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s pump, CEI is investigating whether maintaining this system pressurized. vill be effective in preventing Zebra mussel infestation of the fire protection system.

Samples of water and substrate should be collected annually'to j D.

determine if Asiatic class have populated the water source. Vater 1 and substrate sampling is only necessary at freshwater plants that i have not previously detected the presence of Asiatic class in their l source water bodies. -If Asiatic class are detected, utilities'may _

discontinue this sampling activity if desired, and the chlorination (or equally effective) treatment-program should be modified to be in agreement with paragraph B, above.

Response

J Substrate sampling is currently performed on a quarterly basis to ~

detect Asiatic clams at PNPP in accordance with a requirement in our Environmental Protection Plan (Appendix B to the Operating License).-

As noted above, Asiatic clams have not yet been detected at PNPP, .

-however Zebra mussels have been. Since treatment programs are being

-instituted to control Zebra mussel growth, consideration is being l

given to discontinuing the complete Asiatic clam monitoring program l- currently being conducted. Separate correspondence on this subject l vill be provided to the NRC if it is determined that the current o sampling program is not necessary.

1 II. " Conduct a test program to verify the heat transfer 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 the initial-test program and the periodic retest program should include heat exchangers_ connected-to or cooled by one or more open-cycle systems as defined above. Operating experience and studies

' indicate that closed-cycle service water systems, such as component cooling water systems,-have the potential'for significant fouling as a consequence of' aging-related in-leakage and erosion or corrosion. The need for testing of closed-cycle system heat exchangers has not been h considered necessary because of the assumed high quality of existing ,

' chemical control programs. If the adequacy of these chemistry control l . programs cannot be confirmed over the total operating history of the ,

c plant, or-if during the conduct of the total testing program any unexplained downward trend in heat exchanger performance is identified that cannot be remedied by maintenance of an open-cycle system, it may be l

necessary to selectively extend the test program and the routine inspection and maintenance program addressed in Action III, belov, to the attached closed-cycle systems.

.A program acceptable to the NRC for heat exchanger testing is described in '

" Program for Testing Heat Transfer Capability" (Enclosure 2) [to the L

Generic Letter]. It should be noted that Enclosure 2 is provided as l guidance for an acceptable program. An equally effective program to ensure satisfaction of the heat removal requirements of the service water system would also be acceptable.

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i Attachnsnt

~~ PY-CEI/NRR-1121 h i Page 4 of 7 J l

Testing'should~be done with necessary and sufficient instrumentation,

'though the instrumentation need not be permanently installed. The 1

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relevant-temperatures should be verified to be within design limits. If =

similar or equivalent tests have not been performed duting the past year, the initial tests should be completed before plant startup following the first refueling outage beginning 9 months or more after the date of this  :

letter. 1

~As a part of the initial test program, a licensee or applicant may decide to take corrective action before testing. Tests should be performed for '

the heat exchangers after the corrective ~ actions are taken to establish baseline data for future monitoring of heat exchanger performance. In the periodic retest program, a licensee or applicant should determine after '

three tests the-best frequency for testing to provide assurance that the equipment vill perform the intended safety functions during the intervals between tests. Therefore, in the periodic retest program, to assist that '

determination, tests should be performed for the heat exchangers before-any, corrective actions are taken. As in the initial test program, tests should be repeated after any corrective actions are taken to establish baseline data for future monitoring of heat exchanger performance.

An. example of an alternative action that would be acceptable.to the NRC is .

freqsent. regular maintenance of a heat exchanger in lieu of testing for degraded performance of the heat exchanger. This alternative might apply to small heat exchangers, such as lube oil coolers or pump bearing coolers or readily serviceable heat exchangers located in low radiation areas of

!- the facility. '

1 In implementing the continuing program for periodic retesting of safety-related heat exchangers cooled by service water in open-cycle systems, the initial ~ frequency of testing should be at least once each s fuel cycle, but after three . tests, licensees and applicants should ,

n determine the best frequency for testing to provide assurance that the L

equipment vill perform the intended safety functions during the intervals E

between tests-and meet the requirements of GDC 44, 45 and 46. ,

i The minimum final testing frequency should be once every 5 years. A summary of the program should be documented, including the schedule for tests, and.all relevant documentation should be retained in appropriate plant records."

? Response L

P Performance testing of ESV vater-to-vater heat exchangers vill be H implemented with the primary objective of determining whether biofouling/ corrosion has reduced the overall heat transfer coefficient sufficiently to reduce the quantity of heat that can be transferred at p design conditions. Test conditions may be different than design, as long i

l' as the heat transfer coefficient can be accurately determined. Initially L the schedule for ESV vater-to-vater heat exchangers performence testing vill be each refuel outage, beginning with our second refuel outage. The retests will include both pre- and post- corrective action testing (if corrective action, e.g. cleaning, is done) in order to provide data for I = _ _

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At tech:cnt PY-CEI/NRR-1121 L  ;

Page 5 of 7 determination of future schedules and to allow consistent baseline data comparisons. Test procedures / schedules vill be prepared, and records  ;

retained,J for the purpose of verifying the ESV vater-to-vater heat c

J exchangers' capability. The best frequency for such testing / inspection b vill be determined after fourth refueling outage results are evaluated, L but a minimum frequency of once every 5 years vill be maintained. The ESV '

L air-to-vater heat exchanger (HPCS room cooler) vill be inspected and cleaned at:each refuel outage, fin and tube side, as an alternative to performance testing. Existing chemistry control programs for closed-cycle systems have been adequate to preclude biological fouling over PNPP's ,

operating history. Without significant degradation.in heat exchanger performance, it is concluded that extension of the ..

test / inspection / maintenance programs beyond ESV is not varranted. In addition, established plant procedures vould serve to address any i R

degradation in the performance of interfacing closed cycle systems. j III. "Enswe by establishing a routine inspection and me.intenance 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. The maintenance program should have at least the following purposes A. To_ remove excessive accumulations of biofouling agents, corrosion

! products, and silt; B. To repair defective protective coatings and corroded service water system piping and components that could adversely affect performance of their intended safety functions.

This program should be established before plant startup following the first refueling outage beginning 9 months af ter the date of this letter. ~

'A description of the program and the results of these maintenance

-inspections should be documented. All relevant documentation should be retained in appropriate plant records."

Response

An ongoing maintenance program has been described above for inspection and maintenance of the ESV intake structures, HPCS room cooler, and fire protection system. In addition, rav vater-systems are inspected for clams when open for maintenance or repair. Starting with our second refuel outage, one loop of the ESV system and a heat exchanger in that loop (three loops total) vill be visually inspected, cleaned as necessary, and appropriate testing conducted for evidence of HIC or other corrosion, on a rotating basis. Consistent vith heat exchangers performance testing discussed in II above, the best frequency for inspection and cleaning vill be determined after the fourth refueling outage. Appropriately scheduled instructions, including records, vill be prepared for this purpose. Due to the fact ESV piging is not in use during normal plant operation and operates below 200 F, the ESV system is not included in the PNPP erosion / corrosion monitoring program (described in PY-CEI/NRR-0708L, 9/8/87, PY-CEI/NRR-1034L, 7/20/89, and PY-CEI/NRR-1096L,11/14/89).

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Attcchasnt PY-CEI/NRR-ll21 L Page 6 of 7 ,

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IV. " Confirm that the service water system vill perform its intended function in accordance with the licensing basis for the plant. Reconstitution of 1 the 6esign 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 valkdown inspections. This confirmation should be completed

-before plant startup following the first refueling outage beginning 9 months.or more after the date of this letter. Results should be documented and retained in appropriate plant records." .

Response

L The Emergency Service Vater System has been evaluated using Safety System ,

Functional Inspection (SSFI) techniques by CEI staff during the first quarter of 1989. The ESV design bases, calculations, preoperational testing, plant operations, component performance and system interfaces were evaluated. Earlier the ESV System vas walked down to verify its as-built configuration prior to fuel load (March, 1986). Since that time, design changes have been controlled by a formal program which reviews impacts on the design basis and verifies as-built configuration.

Considering the effectiveness of this design control program, additional .i valkdowns are not considered necessary or justified. Our design reviev l and follovup actions have confirmed that the ESV system vill perform its l

intended function in accordance with the PNPP licensing basis. Resolution l

of remaining SSFI concerns (which do not. impair this function) vill be i documented and retained in appropriate' plant records.

L V. " Confirm that maintenance practices, operating and emergency procedures,.

' L and training that involves the service water system are adequate to ensure that safety-related equipment cooled by the service water system vill

! function as intended and that operators of this equipment-vill perform y

effectively. This confirmation should include recent (within the'past 2 t L

years) reviews of practices, procedures, and training modules. The intent E

of this action is to reduce human errors in the operation, repair and

! maintenance of the service water system. This confirmation should be completed before plant startup following the first refueling outage beginning 9 months or more after the date of this letter. .Results should be documented and retained in appropriate plant records."

Response

The requested review has been completed, and CEI confirms that ESV maintenance practices, operating and emergency procedures, and training are adequate. The review emphasized operating and maintenance errors in

Att chment-

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NUREG-1275, Volume 3 entitled, " Operating Experience Feedback Report -

'- . Service Water System Failures and Degradations". Operating procedures

vere reviewed with attention focused on system restoration following-maintenance. Procedures and instructions reviewed-included ESV operation, valve and electrical lineup instructions, and administrative controls for system restoration. NUREC-1275 also identifies valve locking programs as being a potential solution to mispositioning errors. The PNPP

-locked valve program addresses ESV throttle valves to heat exchangers and valves that cross connect Emergency Service Water to Fuel Pool Cooling,-

Fire Water, and RHR systems. In addition, because the Emergency Service '

Water System is safety reinted, repositioning of its components requires independent verification which is provided by PNPP administrative procedura.

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