Information Notice No. 94-03: Deficiencies Identified During Service Water System Operational Performance Inspections
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
January 11, 1994
NRC INFORMATION NOTICE 94-03: DEFICIENCIES IDENTIFIED DURING SERVICE WATER
SYSTEM OPERATIONAL PERFORMANCE INSPECTIONS
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert the addressees to deficiencies identified by the NRC during
service water system operational performance inspections that were recently
performed. It is expected that recipients will review the information for
applicability to their facilities and consider actions, as appropriate, to
avoid similar problems. However, suggestions contained in this information
notice are not NRC requirements; therefore, no specific action or written
response is required.
Description of Circumstances
Design and operational concerns associated with service water systems have
been identified in licensee event reports and during NRC inspection
activities. To address these concerns, the NRC issued Generic Letter 89-13,
"Service Water System Problems Affecting Safety-Related Equipment," on
July 18, 1989. This generic letter requested that licensees and applicants
perform actions to ensure that their service water systems are in compliance
with 10 CFR Part 50 (Appendix A, General Design Criteria 44, 45, and 46 and
Appendix B, Section XI). The NRC conducted four workshops on Generic
Letter 89-13 and issued information developed from the transcripts of these
workshops as Supplement 1 to the generic letter on April 4, 1990.
Because problems continued to be experienced with service water systems, the
NRC developed the service water system operational performance inspection to
assess licensee actions in response to Generic Letter 89-13 and to evaluate
such aspects of the service water system as design, operations, maintenance,
surveillance/testing, and quality assurance/corrective actions. These
inspections are performed in accordance with Temporary Instruction 2515/118,
Revision 1, "Service Water System Operational Performance Inspection
(SWSOPI)," contained in the NRC Inspection Manual. As indicated in the
temporary instruction, these inspections will generally be conducted at plants
licensed before 1979, as well as at newer plants that are perceived to have
service water system problems or more general maintenance, engineering, and
technical support problems.
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Discussion
During the initial seven service water system operational performance
inspections, deficiencies and weaknesses were found in the evaluation of heat
transfer requirements and in the development of testing programs and
procedures. In addition, the results of these inspections indicated that, in
general, licensees have not taken all actions requested by Generic
Letter 89-13 in a completely effective manner.
Some examples of the deficiencies and weaknesses that were identified during
the initial inspections are summarized in this section.
(1) Evaluation of Heat Transfer Requirements
The findings in this area pertain to inadequacies in analyses of the heat
loads to be removed by the service water systems, evaluations of the
performance of the heat exchangers and room coolers, and verification of
hydraulic analyses. For example, the following deficiencies were
identified:
o The calculated heat load in a compartment containing safety-related
pumps exceeded the rated room cooler capacity. Also, initial
calculations failed to include heat loads from auxiliary motors
located in the compartment. During the inspection, the licensee
performed a new calculation and determined that equilibrium room
temperature would be higher than the existing analyzed temperature in
the compartment. Additional evaluations were performed to verify that
the electrical equipment in these areas could operate at the higher
room temperature. (Quad Cities)
o A calculation to demonstrate the heat removal capacity of a safety-
related room cooler failed to consider that the actual flow through
the room cooler was less than design flow. (Monticello)
(2) Testing Programs and Procedures
The findings in this area are related to failure to include safety-
related service water system valves in the inservice testing (IST)
program, failure to perform required tests in accordance with the IST
program, failure to test the service water system components to verify
their functional capabilities, and failure to use appropriate test
acceptance criteria. For example, the following deficiencies were
identified:
o Various safety-related valves were omitted from the IST programs at
several plants. In one case, many manual valves in the service water
system that perform specific functions in shutting down the reactor
were not included in the IST program. In another case,.
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manual valves and check valves that perform safety functions in
aligning the emergency backwash lines to the essential service water
strainers were not included in the IST program. Also, power-operated
flow-control valves that are normally closed, but perform a safety
function in opening to admit service water flow, were not included in
the IST program. (Monticello, South Texas, Quad Cities)
o Periodic testing of valves as required by the IST program was not
performed. The service water system valves in the control room
heating, ventilation, and air conditioning system were not tested
quarterly, as required by the plant's IST program. (Quad Cities)
o Deficiencies were noted in IST programs for the service water system
pumps. The service water pump curves were used in testing the pumps
instead of specific reference values as required by Section XI of the
ASME Boiler and Pressure Vessel Code (ASME Code) without obtaining NRC
staff approval for relief from the provisions of the Code. Flow
instruments that were not in compliance with the instrument accuracy
requirements specified by Section XI of the ASME Code were used in the
testing of essential cooling water pumps without obtaining relief from
the Code requirements. (Monticello, South Texas)
o The preoperational test results of the service water system had not
been reconciled with the current system configuration and operation.
For example: (a) the system was tested with the nonsafety-related
portions isolated, although the existing operation of the system did
not isolate these portions on a safety injection signal alone, (b) the
system was not tested with two pumps operating to verify system
performance under post-accident recirculation conditions, and (c) the
system flow balance was established on the basis of three-pump
operation instead of the limiting case of one-pump operation supplying
all the loads. (Ginna)
(3) Weaknesses in the Implementation of Generic Letter 89-13
In addition to the specific deficiencies discussed above, weaknesses were
noted in the implementation of Generic Letter 89-13 actions. Significant
weaknesses in the implementation of Actions II and III of Generic Letter
89-13 are discussed below.
Action II of Generic Letter 89-13 requested that licensees establish a
test program to periodically verify the heat transfer capability of all
safety-related heat exchangers cooled by service water. The total test
program was to consist of an initial test program and a periodic retest
program. The following examples illustrate some of the implementation
weaknesses found at one or more plants for this action item:
o Several safety-related room coolers were not tested in accordance with
commitments in the licensee response to the generic letter.
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o No baseline testing was done to verify that minimum flow to each
component was achieved.
o Where the periodic maintenance method was chosen in lieu of heat
transfer performance testing of heat exchangers and room coolers, no
sound technical basis for inspection and preventive maintenance
frequencies was established.
o The design temperature difference across a heat exchanger was used as
an acceptance criterion without correcting for the actual test
conditions where the test heat load was substantially less than the
design value.
Action III of Generic Letter 89-13 requested that licensees establish a
routine inspection and maintenance program for open-cycle service water
system piping and components to ensure that corrosion, erosion,
protective coating failure, silting, and biofouling would not degrade the
performance of the safety-related systems supplied by service water. The
following examples illustrate some of the implementation weaknesses found
at one or more plants for this action item:
o Adequate training or guidance was not provided for personnel to
evaluate potentially degraded conditions of service water system
components.
o Maintenance and inspection programs did not provide assurance that
critical instrument lines and small-bore piping would not become
clogged or degraded.
o Actions were not taken within a reasonable time period to inspect and
clean room coolers in the second unit when similar coolers in the
first unit were found to be significantly degraded.
o Nonsafety-related service water system piping in the discharge path
from safety-related components was not included in an inspection and
maintenance program.
The findings of these inspections illustrate the importance of systematic
engineering analyses, testing, inspection, and maintenance of service water
systems.
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This information notice requires no specific action or written response. If
you have any questions about the information in this notice, please contact
the technical contacts listed below or the appropriate NRR project manager.
/S/'D BY BGRIMES
Brian K. Grimes, Director
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts: S. K. Malur, NRR
(301) 504-2963
S. R. Jones, NRR
(301) 504-2833
Attachments:
1. List of SWSOPI Reports
2. List of Recently Issued NRC Information Notices.
Attachment 1 IN
94-03 January 11,
1994 Page 1 of 1
List of SWSOPI Inspections
The following seven SWSOPI reports were reviewed to identify the types of
deficiencies and weaknesses that are discussed in this information notice:
1. 50-237/93008(DRS); 50-249/93008(DRS) (Dresden Nuclear Power Station)
2. 50-244/91-201 (Ginna Nuclear Power Station)
3. 50-335/91-201; 50-389/91-201 (St. Lucie Plant)
4. 50-263/92010 (Monticello Nuclear Generating Plant)
5. 50-254/92-201; 50-265/92-201 (Quad Cities Nuclear Power Station)
6. 50-498/92-201; 50-499/92-201 (South Texas Project)
7. 50-397/93-201 (Washington Nuclear Plant, Unit
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