Service Water System Problems Affecting Safety-Related Equipment (Generic Letter 89-13)
July 18, 1989
TO: ALL HOLDERS OF OPERATING LICENSES OR CONSTRUCTION PERMITS
FOR NUCLEAR POWER PLANTS
SUBJECT: SERVICE WATER SYSTEM PROBLEMS AFFECTING SAFETY-RELATED 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"
(UHS). "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-
cants 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. 81-03: The NRC staff has been studying the problems associated
with service water cooling systems for a number of years. At Arkansas Nuclear
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
8907180211
.Generic Letter 89-13 -2- 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)."
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 the
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 surprisingly, 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 activities 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 Document for Generic Issue 51...," NUREG/
CR-5210. The NRC has concluded that the issue will be resolved when licensees
.Generic Letter 89-13 -3- 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
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,
Rancho Seco LER 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 violations were identified (NRC Inspection Reports
50-280/88-32 and 50-281/88-32).
AEOD Case Study: In 1987, the Office for Analysis and Evaluation of
Operational Data (AEOD) in the NRC initiated a systematic and comprehensive
review and evaluation of service water system failures and degradations at
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
percent), 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 significant equipment failures (4
percent).
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
exchangers, which are cooled by the service water system and which
are needed to perform a safety function, to verify heat exchanger
heat transfer capability.
.Generic Letter 89-13 -4- 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 compliance and will be maintained in
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
chemistry 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
considered 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.)
I. 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 to 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
biofouling would also be acceptable. 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.
II. Conduct a test program to verify the heat transfer capability of all
safety-related heat exchangers cooled by service water. The total
test
.Generic Letter 89-13 -5- 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 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 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
maintenance program addressed in Action III, below, to the attached
closed-cycle systems.
A program acceptable to the NRC 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 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.
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.
.Generic Letter 89-13 -6- 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;
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
.Generic Letter 89-13 -7- 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
Regulatory 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 recommended 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
information 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.
.Generic Letter 89-13 -8- July 18, 1989
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,
James G. Partlow
Associate Director for Projects
Office of Nuclear Reactor Regulation
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
. 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 removal 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).
Chlorination or equally effective treatment is included for freshwater
plants without clams because it can help prevent microbiologically 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 tested on a regular schedule to ensure that they are not fouled
or
. -2-
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.
D. Samples of water and substrate should be collected annually to determine
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.
. Enclosure 2
PROGRAM FOR TESTING HEAT TRANSFER CAPABILITY
This enclosure describes a program acceptable to the NRC for meeting the
objectives of the requested Action II in the proposed generic letter. Both
Action II 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.
. -2-
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
capabilities. 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 temperature and service water flow and temperature
could be monitored and trended during the diesel 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
exchanger 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,
for 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 off-design conditions.
Design heat removal capacity should be verified. Results
should be trended, as explained above, to identify any degraded
equipment.
. -3-
B. If it is not possible to test the heat exchanger to provide
statistically significant results (for example, if error in the
measurement exceeds the value of the parameter being measured),
then
1. Trend test results for both the air and water flow rates
in the heat exchanger.
2. Perform visual inspections, where possible, of both the
air 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,
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 above, 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 is
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.
. Enclosure 3
INFORMATION NOTICES 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. Information Notice No. 85-24: "Failures of Protective Coatings in
Pipes and Heat Exchangers," March 26, 1985
3. Information Notice No. 85-30: "Microbiologically Induced Corrosion
of Containment Service Water System," April 19, 1985
4. Information Notice No. 86-96: "Heat Exchanger Fouling Can Cause
Inadequate Operability of Service Water Systems," November 20, 1986
5. Information Notice No. 87-06: "Loss of Suction to Low Pressure
Service Water System Pumps Resulting from Loss of Siphon,"
January 30, 1987
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