ML20247H416
| ML20247H416 | |
| Person / Time | |
|---|---|
| Issue date: | 07/18/1989 |
| From: | Partlow J Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| GL-89-13, NUDOCS 8907310002 | |
| Download: ML20247H416 (1) | |
Text
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4 July 18, 1989 i MEMORANDUM FOR: All NRR Project Managers FROM: James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation
SUBJECT:
GENERIC LETTER 89-13 Enclosed is Generic Letter 89-13 requiring responses from licensees and applicants concerning compliance of their nuclear power plant service water
- systems with 10 CFR Part 50, Appendix A, General Design Criteria 44, 45, and 46 and with 10 CFR Part 50, Appendix B, Section XI.
Licensees and applicants shall advise the NRC within 180 days of their receipt of this Generic Letter whether they have established programs to implement recommendations 1-V of this Generic Letter or equally effective alternative courses of action. These responses shall include schedules of plans for implementation of the various actions.
In addition to the 180-day response, each licensee and applicant shall confirm to the NRC that all the recommended actions or their justified alternatives have been implemented within 30 days of such implementation. This response need only be a single response to indicate that all initial tests or activities have been completed and that continuing programs have been established.
l Issuance of this Generic Letter has been approved by the CRGR by memorandum from E. Jordan to V. Stello dated July 7,1989.
ORIGINAL SIGib 1AffES 4. PARTLU James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation
Enclosure:
Generic Letter 89- 13 cc w/ enclosures:
J. Taylor H. Thompson Division Directors, NRR g k\
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- July le, 1989 TO: ALL HOLDERS OF OPERATING LICENSES OR CONSTRUCTION PERMITS FOR NUCLEAR POWER PLANTS
SUBJECT:
SERVICE WATER SYSTEM PROBLEMS AFFECTING f JF N RE'ATED EQUIPMENT (GENERIC LETTER 89-13)
Purpose:
Nuclear power plant facilities of licensees and applicants must meet the minimum requirements of the General Design Criteria (GDC) in 10 CFR Part 50, Appendix A. In particular, "GDC 44--Cooling Water" requires provision of a system (here called the service water system) "to transfer heat from struc-tures, systems, and components important to safety to an ultimate heat sink" (VHS). "GDC 45--Inspection of Cooling Water System" requires the system design "to permit appropriate periodic inspection of important components, such as heat exchangers and piping, to assure the integrity and capability of the system." "GDC 46--Testing of Cooling Water System" requires the design "to permit appropriate periodic pressure and functional testing."
In addition, nuclear power plant facilities of licensees and applicants must meet the minimum requirements for quality assurance in 10 CFR Part 50, Appendix B. In particular,Section XI, " Test Control," requires that "a test program shall be established to assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service is identified and performed in accordance with written test procedures which incorporate the requirements and acceptance limits contained in applicable design documents."
Recent operating experience and studies have led the NRC to question the compliance of the service water systems in the nuclear power plants of
-licensees and applicants with these GDC and quality assurance requirements.
Therefore, this Generic Letter is being issued to require licensees and appli-cents to supply information about their respective service water systems to assure the NRC of such compliance and to confirm that the safety functions of their respective service water systems are being met.
Background:
Bulletin No. 21-03: The NRC staff has been studying the problems associated l
with service water cooling systems f or a number of years. At Arkansas Nuclear 1 One, Unit 2, on September 3,1980, the licensee shut down the plant when the NRC Resident Inspector discovered that the service water flow rate through the CONTACT: C. Vernon Hodge, NRR 492-1169 QWribOw ~
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- l. l Generic Letter 89-13 July 18, 1989 containment cooling units did not meet the technical specification requirement.
The licensee determined the cause to be extensive flow blockage by Asiatic '
clams (Corbicula species, a non-native fresh water bivalve mollusk). Prompted by this event and after determining that it represented a generic problem of safety significance, the NRC issued Bulletin No. 81-03, " Flow Blockage of Cooling Water to Safety System Components by Corbicula sp. (Asiatic Clam) and Mytilus sp. (Mussel)." j The bulletin required licensees and applicants to assess macroscopic biological fouling (biofouling) problems at their respective facilities in accordance with ;
specific actions. A careful assessment of responses to t% bulletin indicated that existing and potential fouling problems are generally unique to each facility (" Closeout of IE Bulletin 81-03...", NUREG/CR-3054), but that surpris-ingly, more than half the 129 nuclear generating units active at that time were considered to have a high potential for biofouling. At that time, the activi-ties of licensees and applicants for biofouling detection and control ranged widely and, in many instances, were judged inappropriate to ensure safety system reliability. Too few of the facilities with high potential for biofouling had adopted effective control programs.
Information Notice No. 81-21: After issuance of Bulletin No. 81-03, one event at San Onofre Unit 1 and two events at the Brunswick station indicated that conditions not explicitly discussed in the bulletin can occur and cause loss of direct access to the UHS. These conditions include
- 1. Flow blockage by debris from shellfish other than Asiatic clams and blue mussels.
- 2. Flow blockage in heat exchangers causing high pressure drops that can deform baffles and allow flow to bypass heat exchanger tubes.
- 3. A change in operating conditions, such as a change from power opera-tion to a lengthy outage, that permits a buildup of biofouling organisms.
The NRC issued Information Notice No. 81-21 to describe these events and concerns.
Generic Issue 51: By March 1982, several reports of serious fouling events caused by mud, silt, corrosion products, or aquatic bivalve organisms in open-cycle service water systems had been received. These events led to plant shutdowns, reduced power operation for repairs and modifications, and degraded modes of operation. This situation led the NRC to establish Generic Issue 51,
" Improving the Reliability of Open-Cycle Service Water Systems." To resolve this issue, the NRC initiated a research program to compare alternative surveillance and control programs to minimize the effects of fouling on plant safety. Initially, the program was restricted to a study of biofouling, but in 1987 the program was expanded to also address fouling by mud, silt, and corrosion products.
This research program has recently been completed and the results have been published in " Technical Findings Docrnent for Generic Issue 51... ," NUREG/
CR-5210. The NRC has concluded that che issue will be resolved when licensees
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Generic Letter 89-13 July 18,1989 and applicants implement either the recommended surveillance and control program described below (Enclosure 1) or its equivalent for the service water system at their respective facilities. Many licensees experiencing service 'j water macroscopic biofouling problems at their plants have found that these techniques will effectively prevent recurrence of such problems. The examina-tion of alternative corrective action programs is documented in "Value/ Impact Analysis for Generic Issue 51. . . ," NUREG/CR-5234.
Continuing Problems: Since the advent of Generic Issue 51, a considerable number of events with safety implications for the service water system have been reported. A number of these have been described in information notices, which are listed in "Information Notices Related to Fouling Problems in Service Water Systems" (Enclosure 3). Several events have been reported within the past 2 years: Oconee Licensee Event Report (LER) 50-269/87-04, Rancao Seco LER 1 50-312/87-36, Catawba LER 50-414/88-12, and Trojan LER 50-344/88-29. In the {
fall of 1988, the NRC conducted a special announced safety system functional inspection at the Surry station to assess the operational readiness of the service water and recirculation spray systems. A number of regulatory viola- i tions were identified (NRC Inspection Reports 50-280/88-32 and 50-281/88-32). j AE00 Case Study: In 1987, the Office for Analysis and Evaluation of j Operational Data (AE00) in the NRC initiated a systematic and comprehensive {
review a:id evaluation of service water system failures and degradations at j light water reactors from 1980 to early 1987. The results of this AEOD case study are published in " Operating Experience Feedback Report - Service Water System Failures and Degradations," NUREG-1275, Volume 3 (Enclosure 4).
Of 980 operational events involving the service water system reported during this period, 276 were deemed to have potential generic safety significance. A majority (58 percent) of these events with generic significance involved system fouling. The fouling mechanisms included corrosion and erosion (27 r1rcent),
biofouling (10 percent), foreign material and debris intrusion (10 percent), .
sediment deposition (9 percent), and pipe coating failure and calcium carbonate deposition (1 percent). ;
The second most frequently observed cause of service water system degradations and failures is personnel and procedural errors (17 percent), followed by seismic deficiencies (10 percent), single failures and other design deficien-cies (6 percent), flooding (4 percent), and significar.t equipment failures (4 percent). a During this period, 12 events involved a complete loss of service water system function. Several of the significant causes listed above for system degrada-tion were also contributors to these 12 events involving system failure.
The study identified the following actions as potential NRC requirements.
- 1. Conduct, on a regular basis, performance testing of all heat exchang-ers, which are cooled by the ;,ervice water system and which are needed to perform a safety function, to verify heat exchanger heat transfer capability.
1 .
Generic Letter 89-13 July 18, 1989
- 2. Require licensees to verify that their service water systems are not vulnerable to a single failure of an active component.
- 3. Inspect, on a regular basis, important portions of the piping of the {
service water system for corrosion,. erosion, and biofouling.
- 4. Reduce human errors in the operation, repair, and maintenance of the service water system.
Recommended Actions To Be Taken by Addressees:
On the basis of the discussion above, the NRC requests.that licensees and applicants perform the following or equally effective actions to ensure that !
their service water systems are in compliante and will be maintained in I l
compliance with 10 CFR Part 50, Appendix A, General Design Criteria 44, 45, and 46 and Appendix B,Section XI. If a licensee or applicant chooses a course of action different from the recommendations below, the licensee or applicant should document and retain in appropriate plant records a justification that the heat removal requirements of the service water system are satisfied by use of the alternative program. ,
Because the characteristics of the service water system may be unique to each facility, the service water system is defined as the system or systems that transfer heat from safety-related structures, systems, or components to the UHS. If an intermediate system is used between the safety-related items and the system rejecting heat to the UHS, it performs the function of a service water system and is thus included in the scope of this Generic Letter. A closed-cycle system is defined as a part of the service water system that is not subject to significant sources of contamination, one in which water chemis-try is controlled, and one in which heat is not directly rejected to a heat sink. If all these conditions are not satisfied, the system is to be consid-ered an open-cycle system in regard to the specific actions required below.
(The scope of closed cooling water systems is discussed in the industrial standard " Operation and Maintenance of Nuclear Power Plants," ASME/ ANSI OM-1987, Part 2.)
- 1. For open-cycle service water systems, implement and maintain an ongoing program of surveillance and control techniques to signifi-cantly reduce the incidence of flow blockage problems as a result of biofouling. A program acceptable tn the NRC is described in "Recom-mended Program to Resolve Generic Issue 51" (Enclosure 1). It should be noted that Enclosure 1 is provided as guidance for an acceptable program. An equally effective program to preclude biofou?ing would also be acceptable. Initial activities should be completeo before plant startup following the first refueling outage beginning S months ]
or more af ter the date of this letter. All activities should b? {
documented and all relevant documentation should be retained in 1 appropriate plant records. j II. Conduct a test program to verify the heat transfer capability of all safety-related heat exchangers cooled by service water. The total test 1
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.- 1 Generic letter 89-13 July 18, 1989 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 poi.ential 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 considered necessary because of the assumed high quality of existing chemistry control programs. If the adequacy of these chemistry control programs cannot be confirmed over the total operating' history of the 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 necessary to selectively extend the test program and the routine inspection and 1 maintenance program addressed in Action III, below, to the attached )
closed-cycle systems.
A program acceptable to the NP.C for heat exchanger testing is de-scribed in " Program for Testing Heat Transfer Capability" (Enclosure 2). It should be noted that Enclosure 2 is provided as 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.
Testing should be done with necessary and sufficient instrumentation, though the instrumentation need not be permanently installed. The relevant temperatures should be verified to be within design limits.
If similar or equivalent tests have not been performed during the past i year, the initial tests should bo completed before plant startup following the first refueling outage beginning 9 months or more after the date of this letter.
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 will 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 frequent regular maintenance of a heat exchanger in lieu of ;
testing for degraded performance of the heat exchanger. This alter-native 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.
j
..h Generic Letter 89-13 July 18, 1989 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 fuel cycle, but after three tests, licensees and applicants should determine the best frequency for testing to provide assurance that the equipment will perform the intended safety functions during the intervals between tests and meet the requirements of GDC.44, 45, and 46. 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.
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. The maintenance program should have at least the following purposes:
A. To remove excessive accumulations of biofouling agents, corro--
sion products, and silt; i
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 after the date of this letter. A description of the program and the results of these maintenance inspections should be documented. All relevant documen-tation should be retained.in appropriate plant records.
IV. Confirm that the service water 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 walkdown 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.
V. Confirm that maintenance practices, operating and emergency proce-dures, 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 j
Generic Letter 89-13 July 18, 1989 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.
Reporting Requirements:
Pursuant to the provisions of Section 182a of the Atomic Energy Act of 1954, as amended, and 10 CFR 50.54(f), each licensee and applicant shall advise the NRC whether it has established programs to implement Recommendations I-V of this Generic Letter or that it has pursued an equally effective alternative course of action. Each addressee's response to this requirement for information shall be made to the NRC within 180 days of receipt of this Generic Letter.
Licensees and applicants shall include schedules of plans for implementation of the various actions. The detailed documentation associated with this Generic Letter should be retained in appropriate plant records.
The response shall be submitted to the appropriate regional administrator under oath and affirmation under the provisions of Section 182a, Atomic Energy Act of 1954, as amended and 10 CFR 50.54(f). In addition, the original cover letter and a copy of any attachment shall be transmitted to the U.S. Nuclear Regu-latory Commission, Document Control Desk, Washington DC 20555, for reproduction and distribution.
In addition to the 180-day response, each licensee and applicant shall confirm to the NRC that all the recommended actions or their justified alternatives have been implemented within 30 days of such implementation. This response need only be a single response to indicate that all initial tests or activities have been completed and that continuing programs have been established.
This request is covered by the Office of Management and Budget Clearance Number 3150-0011, which expires December 31, 1989. The estimated average burden is 1000 man-hours per addressee response, including assessing the actions to be taken, preparing the necessary plans, and preparing the 180-day response. This estimated average burden pertains only to these identified response-related matters and does not include the time for actual implementation of the recom-mended actions. Comments on the accuracy of this estimate and suggestions to reduce the burden may be directed to the Office of Management and Budget, Reports Management, Room 3208, New Executive Office Building, Washington, DC 20503 and to the U.S. Nuclear Regulatory Commission, Records and Reports Management Branch, Office of Information and Resources Management, Washing-ton, DC 20555.
Although no specific request or requirement is intended, the following informa-I tion would be helpful to the NRC in evaluating the cost of this Generic Letter:
- 1. Addressee time necessary to perform the requested confirmation and any needed follow-up actions.
- 2. Addressee time necessary to prepare the requested documentation.
a.:
Generic; Letter 89-13. July 18, 1989 L If there are any questions regarding this letter, please contact the regional administrator of the appropriate NRC regional office or your project manager in this office.
Sincerely, ORHilMAL SIGNEDTl JANES G. PANhDW James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation
'l'
Enclosures:
- 1. " Recommended Program to-Resolve Generic Issue 51"
- 2. " Program for Testing Heat Transfer Capability" I i
- 3. '"Information Notices Related !
to Fouling Problems in Service Water Systems"
- 4. " Operating Experience Feedback Report - Service Water System Failures and Degradations in Light Water Reactors," NUREG-1275, Volume-3
- 5. List of Most Recently Issued l Generic Letters DISTRIBUTION w/ enclosures TEMurley, NRR JHSniezek, NRR FJMiraglia, NRR JGPartlow, NRR CERossi, NRR CHBerlinger, NRR CVHodge, NRR EJButcher, NRR WDLanning, NRR LShao, NRR MConnor, RI AGibson, RII EJordan, AEOD RBaer, RES Stewis, OGC PDR Central Files DCS DOEA R/F OGCB R/F VHodge R/F This Generic Letter was reviewed by CRGR and discussed in Meeting No.162 on May 10, 989. The committee approved issuance of Generic Letter b memo f rom E. L. J rdan to V. Stello dated July 7,1989. TECH ED BCALUR c HSMITH 7/10/89-
- SEE PREV $ CONCURRENCES 7/11/89 ADP:NR *ADT/NRR *D/DOEA:NRR *C/0GCB:00EA:NRR *0GC ,
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-JGPart FJMiraglia CERossi CHBerlinger SHLewis 06/30/89 06/16/89 02/16/89 02/06/89 07/il/8 *C/EIB:SSIR:RES OGCB:00EA: RR*D/ DEST:NRR *RII *D/AE0D
-CVHodge LCShao AGibson ELJordan RLBaer 07/ll/89 02/15/89 02/06/89 02/16/89 02/07/89
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'O j July 18, 1989-Generic Letter 89-13 l
- If there are',any questions regarding'this letter, please contact the regional i
. administrator of the appropriate NRC regional office or your project manager in 4 1
this office.
Sincerely, J mes G. Partlow i A sociate Director for Projects i l> Of fice of Nuclear Reactor Regulation !
j . --
Enclosures:
- 1. " Recommended Program to Resolve Generic Issue 51"-
- 2. " Program for Testing Heat Transfer Capability"
- 3. "Information Notices Related to Fouling Problems in Service Water Systems"
- 4. " Operating Experience . Feedback -
Report - Service Water System Failures'and Degradations in Light Water Reactors,"' NUREG-1275, Volume 3-
- 5. List of.Most Recently Issued Generic Letters l
~. .
'4 Enclosure 1 RECOMMENDED PROGRAM TO RESOLVE GENERIC ISSUE 51 This enclosure describes a program acceptable to the NRC for meeting the objectives of the requested Action I in the proposed generic letter. Both Action I and this enclosure are based upon the recommendations described in
- " Technical Findings Document for Generic Issue 51: Improving the Reliability of Open-Cycle Service-Water Systems," NUREG/CR-5210, August 1988, and "Value/ Impact Analysis for Generic Issue 51: Improving the Reliability of '
Open-Cycle Service-Water Systems," NUREG/CR-5234, February 1989. The NRC has concluded that Generic Issue 51 will be resolved when licensees and applicants implement either the recommended surveillance and control program addressed in this enclosure or an equally effective alternative course of action to satisfy the heat retroval. requirements of the service water system.
Water Source Surveillance Control Type Techniques Techniques Marine or Estuarine A B and C (brackish) or Freshwater with clams Freshwater without clams A and D B and C A. The intake structure should be visually inspected, once per refueling '
cycle, for macroscopic biological fouling organisms (for example, blue mussels at marine plants, American oysters at estuarine plants, and Asiatic clams at freshwater plants), sediment, and corrosion. Inspections should be performed either by' scuba divers or by dewatering the intake structure or by other comparable methods. Any fouling accumulations should be removed.
B. The service water system should be continuously (for example, during spawning) chlorinated (or equally effectively treated with another biocide) whenever the potential for a macroscopic biological fouling species exists (for' example, blue mussels at marine plants, American oysters at estuarine plants, and Asiatic clams at freshwater plants). j Chlorination or equally effective treatment is included for freshwater i plants without clams because it can help prevent microbiological 1y influ-enced corrosion. However, 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.
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 l tested on a regular schedule to ensure that they are not fouled or
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clogged. Service water cooling loops should be filled with chlorinated or equivalently treated water 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 microbiologically influenced corrosion. Precautions should be taken to obey Federal, State, and local environmental regulations regarding the use of biocides.
l D. Samples of water and substrate should be collected annually to determine L if. Asiatic clams have populated the water source. Water and substrate sampling is only necessary at freshwater plants that have not previously detected'the presence of Asiatic clams in their source water bodies. If Asiatic clams 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.
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l Enclosure 2 l
PROGRAM FOR TESTING HEAT TRANSFER CAPABILITY This enclosure describes a program acceptable to the NRC for meeting the objectives of the requested Action 11 in the proposed generic letter. Both Action 11 and this enclosure are based in part on " Operating Experience feed-back Report - Service Water System Failures and Degradations," NUREG-1275, Volume 3, November 1988 and " Technical findings Document for Generic issue 51:
Improving the Reliability of Open Cycle Service Water Systems," NUREG/CR-5210, August 1988. This enclosure reflects continuing operational problems, inspection reports, and industry standards (" Operation and Maintenance of Nuclear Power Plants," ASME/ ANSI OM-1987, Part 2.) The NRC requests licensees and applicants to implement either the steps addressed in this enclosure or an equally effective alternative course of action to satisfy the heat removal requirements of the service water system.
Both the initial test program and the periodic retest program should include all safety related heat exchangers connected to or cooled by one or more open-cycle service water systems. A closed-cycle system is defined as a part of the service water system that is not subject to significant sources of contamination, one in which water chemistry is controlled, and one in which heat is not directly rejected to a heat sink. (The scope of closed cooling water systems is discussed in the industrial standard, " Operation and Maintenance of Nuclear Power Plants," ASME/ ANSI OM-1987, Part 2.) 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 necessary to selectively extend the test program to the attached closed-cycle system.
Testing should be done with necessary and sufficient instrumentation, though the instrumentation need not be permanently installed.
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 will 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 frequent 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.
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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 fuel cycle, but after three tests, licensees and applicants should determine the best frequency for testing to provide assurance that the equipment will perform the intended safety functions during the intervals between tests and meet the requirements of GDC 44, 45, and 46. The minimum final testing frequency should be once every 5 years.
I. For all heat exchangers Monitor and record cooling water flow and inlet and outlet tempera-tures for all affected heat exchangers during the modes of operation in which cooling water is flowing through the heat exchanger. For each measurement, verify that the cooling water temperatures and flows are within design limits for the conditions of the measurement.
The test results from periodic testing should be trended to ensure that flow blockage or excessive fouling accumulation does not exist.
II. In addition to the considerations for all heat exchangers in Item I, for water-to-water heat exchangers A. Perform functional testing with the heat exchanger operating, if practical, at its design heat removal rate to verify its capa-bilities. Temperature and flow compensation should be made in the calculations to adjust the results to the design conditions.
Trend the results, as explained above, to monitor degradation.
An example of this type of heat exchanger would be that used to cool a diesel generator. Engine jacket water flow and tempera-ture and service water flow and temperature could be monitored and trended during thc dies 9 generator surveillance testing.
B. If it is not practical to test the heat exchanger at the design heat removal rate, then trend test results for the heat exchang-er efficiency or the overall heat transfer coefficient. Verify that heat removal would be adequate for the system operating with the most limiting combination of flow and temperature.
III. In addition to the considerations for all heat exchangers in Item I, f or air-to-water heat exchangers A. Perform efficiency testing (for example, in conjunction with surveillance testing) with the heat exchanger operating under the maximum heat load that can be obtained practically. Test results should be corrected for the of f-design conditions.
Design heat removal capacity should be verified. Results should be trended, as explained above, to identify any degraded equipment.
4L 3
B'.
If it is not possible to test the heat exchanger to provide
~s statistically significant results (for example, if error.in the measurement exceeds the value of the parameter being measured),
j then
- 1. Trend test results for both the air and water flow rates in the heat exchanger.
I- 2.- Perform. visual inspections, where possible, of both the air' I and water sides of the heat exchanger to ensure cleanliness of the heat exchanger.
IV. In addition to the considerations for all heat exchangers in Item I, l
for types of heat exchangers other than water-to-water or air-to-water heat exchangers (for example, penetration coolers, oil coolers, and motor coolers)
A. If plant conditions allow testing at design heat removal condi-tions, verify that the heat exchanger performs its intended functions. Trend the test results, as explained ab'ove, to monitor degradation.
B. If testing at design conditions is not possible, then provide for extrapolation of test data to design conditions. The heat exchanger efficiency or the overall heat transfer coefficient of the heat exchanger should be determined whenever possible. Where
-possible, provide for periodic visual inspection of the heat exchanger. Visual inspection of a heat exchanger that ir an integral part of a larger component can be performed during the regularly scheduled disassembly of the larger component. For example, a motor cooler can be visually inspected when the motor disassembly and inspection are scheduled.
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4 Enclosure 3 INFORMATION N0l:CES RELATED-TO FOULING PROBLEMS IN SERVICE WATER SYSTEMS
- 1. Information Notice No. 83-46: " Common-Mode Valve Failures Degrade -
Surry's Recirculation Spray. Subsystem," July 11, 1983
- 2. .Informatica Notice No. 85-24: " Failures of Protective Coatings.in i Pipes and Heat Exchangers," March 26, 1985 1
"' 3. Inforn.ation Notice No. 85-30: " Microbiological 1y Induced Corrosion-of Containment Service Water System," April 19, 1985-
- 4. Information Notice No. 86-90: " Heat Exchanger Fouling Can Cause Inadequate Operability of Service Water Systems," November 20, 1986
- 5. Information Notice No. 87-n6: " Loss of. Suction to Low Pressure Service Water System Pumps Resulting from Loss of Siphon,"
January 30, 1987
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m Enclosure 5 LIST OF RECEhTLY ISSUED GENERIC LETTERS 1 Date of I Generic !
o Letter No. Subject Issuance Issued To 89-13 GENERIC LETTER 89-13 7/18/89 LICENSEES TO ALL '
SERVICE WATER SYSTEMS POWER REACTORS PROBLEMS AFFECTING BWRS, PWRS, AND SAFETY-RELATED EQUIPMENT VENDORS IN ADDITION TO GENERAL CODES APPLICABLE TO GENERIC LETTERS 89-12 GENERIC LETTER 89-12: 7/6/89 LICENSEES TO ALL OPERATOR LICENSING POWER REACTORS EXAMINATIONS BWRS, PWRS, AND VENDORS IN ADDITION TO GENERAL CODES APPLICABLE TO GENERIC LETTERS 89-11 GENERIC LETTER 89-11: 6/30/89 ALL BWR PLANTS &
RESOLUTION OF GENERIC ISSUE ALL LISTINGS 101 " BOILING WATER REACTOR APPLICABLE TO WATER LEVEL REDUNDANCY" GENERIC LETTERS &
VENDORS, ETC.
89-10 GENERIC LETTER 89-10: 6/28/89 LICENSEES TO ALL' POWER REACTOR 3, SAFETY-RELATED MOTOR-OPERATED VALVE TESTING AND SURVEILLANCE BWRS, PWRS, AND VEh00RS IN ADDITION TO GENERAL CODES APPLICABLE TO GENERIC LETTERS 89-09 ASME SECTION III COMPONENT 5/8/89 ALL HOLDERS OF LIGHT REPLACEMENTS WATER REACTOR OPERATING LICENSES 89-08 ISSUANCE OF GENERIC LETTER 5/2/89 LICENSEES TO ALL POWER REACTORS, 89-08: EROSION / CORROSION -
INDUCED PIPE WALL THINNING - BWRS, PWRS, AND 10CFRGEO.54(f) VENDORS IN ADDITION TO GENERAL CODES APPLICABLE TO GENERIC LETTERS 69-07 GENERIC LETTER 89-07, POWER 4/28/89 LICENSEES TO ALL REACTOR SAFEGUARDS CONTINGENCY BWRS, PWRS, AND PLANNING FOR SURFACE VEHICLE VENDORS IN ADDITION BOMBS TO GENERAL CODES APPLICABLE TO GENERIC LETTERS
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