ML18012A327
| ML18012A327 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 08/07/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML18012A326 | List: |
| References | |
| GL-89-10, NUDOCS 9608130202 | |
| Download: ML18012A327 (5) | |
Text
SAFET U
ION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING EEVALUATION OF SAFETY FUNCTION OF TOR-OPERATED VALVES IN GENERIC LETTER 89-10 PROGRAM CAROLINA OWER AND LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT OCKET NUMBER 50-400 l.
~IMTROOU I IIM On July 15, 1994, Carolina Power 5 Light Company (licensee) notified the NRC of the completion of the motor-operated valve (MOV) program developed in response to Generic Letter (GL) 89-10, "Safety-Related Motor-Operated Valve Testing and Surveillance," at the Shearon Harris Nuclear Power Plant.
Based on positive findings from previous inspections of the licensee's GL 89-10
- program, the NRC staff agreed to consider closing its review of the GL 89-10 program based on a submittal rather than a close-out inspection.
On February 28, 1995, the licensee submitted a close-out package containing information on the implementation of GL 89-10 at Harris.
In its February 28, 1995, submittal, the licensee indicated that the scope of its GL 89-10 program had been reduced from 116 to 88 MOVs based on the criteria provided in Supplements 1 and 6 to GL 89-10.
In response to staff questions during telephone conferences, the licensee submitted followup information on December 7,
1995, describing the basis for the reduction in scope of the Harris GL 89-10 program.
In this Safety Evaluation (SE), the NRC staff provides the results of its review of the licensee's bases for the reduction in the scope of the Harris GL 89-10 program.
2.
CONS DERATIONS IN REVIEWING LICENSEE SCOPE OF GENERIC LETTER 89-10 PROGRAM The NRC staff has been requested by some licensees to review modifications to the scope of their GL 89-10 programs.
For example, the staff provided the results of its review of the reclassification of active safety functions of the GL 89-10 MOVs at the Edwin I. Hatch Nuclear Plant in an SE provided by letter to Georgia Power Company on October 16, 1995.
The following are considerations that the staff used in reviewing the licensee's bases
- for, modifying the scope of the GL 89-10 program at Harris:
a.
The scope of GL 89-10 extends to safety-related MOVs as defined in the NRC regulations (for example, in 10 CFR Part 100).
In GL 89-10, the staff requested licensees to determine the design basis for the operation of each safety-related MOV including the maximum differential pressure expected during both the opening and closing of the MOV for both normal operations and abnormal
- events, to the extent that these MOV operations and events are included in the existing approved design basis.
- b. In Supplement 1 to GL 89-10, the staff stated that safety-related MOVs that are always in their safety position, or would have no affect on the operation of the safety train if placed in the non-safety position, could be removed from the GL 89-10 program.
Containment isolation valves will always have a safety function to close regardless of their system performance requirements.
ENCLOSURE 9608'L30202 960807 PDR ADOCK 05000400 P
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e.
Section 3. 1.2 of NUREG-1482, "Guidelines for Inservice Testing at Nuclear Power Plants,"
issued by GL 89-04 (Supplement 1),
"Guidance on Developing Acceptable Inservice Testing Programs,"
dated April 4, 1995, discusses.
the capability of plant components and surveillance testing.
In this
- regard, safety-related MOVs that are placed in a position that prevents the safety-related system (or train) from performing its safety function must be capable of returning to their safety position, or the system (or train) must be declared inoperable and the appropriate plant technical specifications followed.
In the second footnote in GL 89-10, the staff states that design-basis events are defined as conditions of normal operation, including anticipated operational occurrences, design-basis accidents, external
- events, and natural phenomena for which the plant must be designed to ensure the function delineated as "safety-related" can be performed.
The staff further states in the footnote that the design bases for each plant are those documented in pertinent licensee submittals, such as the final safety analysis report (FSAR).
In Bulletin 85-03, "Motor-Operated Valve Common Mode Failures during Plant Transients due to Improper Switch Settings,"
the staff requested licensees to ensure that MOVs in the high pressure coolant injection/core spray and emergency feedwater systems (Reactor Core Isolation Cooling systems for boiling water reactor (BWR) plants) that are required to be tested for operational readiness in accordance with 10 CFR 50.55a(g) are set and maintained properly.
The consideration of pipe breaks should be consistent with the staff's licensing review for the individual facility (i.e., in accordance with Standard Review Plan (SRP) Section 3.6.2).
Supplements 4 and 7 to GL 89-10 removed the recommendation that licensees of BWR and pressurized water reactor (PWR) nuclear plants, respectively, consider inadvertent mis-positioning of MOVs as part of their GL 89-10 programs.
The consideration of long-term passive failures in piping should be consistent with the staff's licensing review for the individual facility and should be in accordance with SRP 3.6. 1.
- Further, the licensee's evaluation of passive failures must consider valve and pump seal failures as discussed in NRC Commission Paper SECY 77-439.
Licensees may rely on analysis results for each design-basis event and each system's required capability to satisfy event acceptance limits provided in the updated FSAR where the licensee can demonstrate that the information in the updated FSAR is consistent with the licensing basis of the facility.
Licensees are required to meet the single failure criterion in the NRC regulations.
Other criteria may also.apply at the same time (e.g.,
Further, safety systems are required to meet the redundancy provisions of Appendix A to 10 CFR Part 50.
The consideration of the single failure criterion as applied to anticipated operational
transients should be consistent with the staff's licensing review for the individual facility.
3.
EVALUATION The staff's evaluation of the licensee's basis for removing specific HOVs from the GL 89-10 program at Harris is provided below:
1CS-78 er enc Boration Flow Isolation Valve This valve is normally closed and used for boration from the Chemical and Volume Control System (CVCS).
The licensee states that no credit is taken for the boration capabilities of the CVCS as a system in the analysis of the FSAR Chapter 15 transients.
The licensee fur ther stated that this valve does not have a containment isolation function.
Therefore, the staff agrees with the licensee that the repositioning functions of this valve are outside the scope of GL 89-10.
1CT-24 25 4
95 Containment S ra Test Valves The licensee states that these normally closed valves receive a
containment isolation signal to close.
Their function is to open to
'allow testing of the Containment Spray System.
When these valves are
- tested, a Limiting Condition of Operation (LCO) is entered for the appropriate safety train.
The licensee position on these valves is acceptable.
However, to ensure consistency with previous staff guidance, the licensee must enter the LCO whenever the test valves are opened if the licensee cannot demonstrate NOV capability.
1RH-1 2 39 40 Residual Heat Removal RHR Inlet Isolation Valves The licensee states that the primary function of these valves is to isolate the RHR System from the Reactor Coolant System to prevent overpressurizing the system.
They are closed during normal operation with their respective power supply breakers locked off.
The licensee has stated that these valves also do not provide any isolation function, including containment isolation, and that operation of these valves is not a safety function.
Therefore, the open function for these valves is considered outside the scope of GL 89-10.
However, they are opened for residual heat removal during plant cooldown operations.
If these valves do not have a containment isolation function, and closure is not required to satisfy single failure analysis for passive systems (as discussed in NRC Commission Paper SECY 77-439),
then the close function can be considered outside. the scope of GL 89-10.
ISI-246 247 248 Accumulator Dischar e Valves These valves are required to be open during reactor operating modes 1,
2, and 3.
The respective accumulator is declared inoperable when its valve is closed.
Repositioning of these valves for Chapter 15 ev'ents is not
- required, and the licensee stated during the telephone conference that these valves do not have a containment isolation function.
Therefore,
the staff agrees with the licensee that the repositioning functions of these valves are outside the scope of GL 89-10.
1SW-1 23 124 126 127 129 130 132 Service Water to Auxiliar Feedwater
'AFM) Pumps Header Isolation/Backup Valves)
These normally closed valves are opened to allow service water to feed the AFM system if the Condensate Storage Tank (CST) level is low.
The design basis of the CST is to provide sufficient water storage for reactor shutdown decay heat removal by the AFW system.
Availability of the service water connection to AFW is not credited in the FSAR Chapter 15 accident analysis.
Therefore, the staff agrees with the licensee that the repositioning functions of these valves are outside the scope of GL 89-10.
1SW-91 92 97 98 109 110 225 and 201 Containment Fan Cooler Service Mater Su 1
Outlet Isolation Valves The licensee stated that these valves are normally open to provide a flow path for service water supply to the containment fan coolers.
These valves are motor-operated butterfly valves and remain in the open position following an accident.
The licensee stated that the operation of the valves do not represent a safety function, and their oper ation is not necessary to permit the operation of safety-related equipment.
However, the valves are containment isolation valves and are considered safety-related, as specified by the FSAR in Chapter 6.
Although the valves do not receive an automatic actuation signal, the valves can be remotely operated and may need to be operated to perform their containment isolation safety function.
As a result, the staff does not consider the licensee to have provided sufficient information to justify removal of these valves from the Harris GL 89-10 program.
The licensee will be expected to retain these MOVs in its GL 89-10 program or provide additional justification for their removal from the program.
The licensee has verified the capability of these NOVs as part of its GL 89-10 program.
The licensee has compared the vendor calculations for predicting the torque required to operate these valves to differential pressure test data obtained for similar valves and found the vendor prediction to be conservative.
The licensee applies the standard Limitorque guidelines for determining the torque capability of the motor actuators for these limit-switch-controlled butterfly valves.
The staff may review this MOV capability information during a future inspection.
With the conditions and exception discussed
- above, the NRC staff does not object to the licensee's modification to the scope of the GL 89-10 program at Harris.
The staff will expect the licensee to r etain the Containment Fan Cooler Service Mater Supply/Outlet Isolation Valves 1SW-91, 92, 97, 98,
- 109, 110, 225 and 201 in its GL 89-10 program or to provide additional justification for their removal from the program.
For other HOVs discussed in
this SE, the licensee's justification for the change in GL 89-10 program scope may be verified during a future inspection.
5.
~REF RENC Letter to J. T. Beckham from K. N. Jabbour dated October 16, 1995;
Subject:
Reclassification of Generic Letter 89-10 Notor-Operated Valve Active Safety Functions Edwin I. Hatch Nuclear Plant, Units 1 and 2.
Principal Contributors: