ML17158A883
| ML17158A883 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 09/11/1995 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17158A882 | List: |
| References | |
| NUDOCS 9509140155 | |
| Download: ML17158A883 (4) | |
Text
spit ARCS UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055&0001 cs Y/
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SAF TY EVALUATIO 8
T E OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AME DMENT N0.123TO FACILITY OPERATING LICENSE NO.
NPF-22 P NNSYLVANIA POWER
& LIGHT COMPANY LLEGHENY ELECTRIC COOPERATIVE INC.
SUS UEHANN STEAM ELECTRIC STATION UNIT 2 DOCKET NO. 50-388
1.0 INTRODUCTION
By letter dated May 5,
- 1995, as supplemented by letter dated August 18,
- 1995, the Pennsylvania Power and Light Company (PPKL) (the licensee) submitted a
request for changes to the Susquehanna Steam Electric Station (SSES),
Unit 2, Technical Specifications (TS).
The requested changes would delete from SSES Technical Specification Table 3.6.3-1, "Primary Containment Isolation Valves,"
three relief valves in the residual heat removal system.
The August 18,
- 1995, letter provided clarifying information that did not change the initial proposed no significant hazards consideration determination or expand the scope of the original Federal
~Re ister notice.
2.0 BACKGROUND
In its submittal, PP8IL indicated that in the original design of the
- SSES, the residual heat removal (RHR) system included a steam condensing mode.
Since the time of licensing, this mode for the RHR system was eliminated from the plant.
After the mode was eliminated, not all piping and valving was removed.
A design change package has been developed which would remove three RHR system relief valves and would replace the valves with blind flanges or the equivalent.
The proposed TS change would reflect this design change implementation by removing these three valves from the list of containment isolation valves from TS Table 3.6.3-1.
- 3. 0 EVALUATION As indicated in the SSES Final Safety Analysis Report (FSAR), Valves PSV-251F055 A 8 B are pressure relief valves located on the RHR system steam supply line from HPCI steam supply between the RHR heat exchanger and the steam supply pressure control valves.
This steam supply line was previously isolated by welded caps between the pressure control valves and the RHR system.
As per the original design of the SSES units, these relief valves were originally provided to protect the RHR heat exchanger and its shell side inlet piping in the event both pressure control valves failed to open during the steam condensing mode of RHR.
The discharge of the relief valves is directed to the suppression pool.
As noted in the licensee's submittal, these valves were designed to remain closed to maintain RHR system integrity during 95091,40155 IgI50911 PDR ADOCK 05000388 P....,...,.P.DR,
setpoint that could occur during the steam condensing mode.
The size of these valves was established based on the design pressure of the piping and heat exchanger such that the design pressure would not be exceeded by more than lOX during the pressure transient with the pressure control valves in the full open position.
PPKL also stated that these valves are no longer required for the following reasons:
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The steam condensing mode has been eliminated from the RHR system.
Since the HPCI steam supply piping to the RHR heat exchangers was cut and
- capped, the potential for the overpressure condition due to pressure control valve failure in the steam line no longer exists.
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The RHR heat exchanger and associated piping are still protected from a pressure transient caused by thermal expansion by the thermal relief valves provided as part of the original design.
The protection is provided by the heat exchanger shell relief valve when the RHR heat exchanger is isolated and by an additional relief valve when the heat exchanger is not isolated.
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The system and containment boundary integrity will be maintained by installing blind flanges or equivalent.
The third pressure relief valve which the licensee plans to remove is PSV-251FO97.
This valve is located on the RHR system condensate discharge line to RCIC pump suction.
This valve was provided for overpressure protection in the event either control valve fa'iled open during the steam condensing mode of operation.
This valve was designed to remain closed to maintain the pressure integrity of the piping arid to open when the pressure in the piping exceeds the relief setpoint.
The size of this valve was established based on the design pressure of the RCIC pump suction piping such that the piping design pressure would not be exceeded by more than ION during the pressure transient with the control valve in the full open position.
As indicated in the PPKL submittal, this valve is no longer required for the following reasons:
The steam condensing mode has been eliminated from the RHR system.
The potential for an overpressure condition during or following a steam condensing mode of operation does not exist.
In order to eliminate the potential for RHR pressurizing RCIC pump suction piping, the piping between the two systems will be isolated via blind flange or cut and cap.
The RCIC suction piping is still protected from an overpressure condition by a pressure 'relief valve.
This relief valve was provided to protect the RCIC pump suction piping from over-pressurization during standby conditions due to leakage into the RCIC system from higher pressure systems such as the Feedwater System.
The system and containment boundary integrity will be maintained by installing a blind flange or equivalent.
In the staff's safety evaluation for the original containment isolation system
- design, NUREG-0776, April 1981, the staff reflected the results of the review of the containment isolation valves and associated piping and penetrations necessary to isolate the primary containment in the event of a loss-of coolant accident.
The objective of the containment isolation system is to allow the normal or emergency passage of fluids through the containment boundary while preserving the integrity of the containment boundary to prevent or limit the escape of fission products from a postulated loss-of-coolant accident.
The staff concluded in its evaluation that the proposed design of the containment isolation system satisfies the requirements of General Design Criteria 54, 55, 56, and 57 and was found to be acceptable.
As discussed
- above, the modifications made to delete the RHR steam condensing mode have been made.
This has eliminated the need to allow the passage of fluids through these three containment boundaries and the need to open the isolation valves PSV-251F055A, PSV-251F055B, and PSV-251F097.
The existing design with the valves maintained in a closed position meets the GDC listed above and therefore the replacement of each valve with a blind flange or equivalent will also meet these criteria.
- Further, in a letter dated August 18,
- 1995, the licensee indicated that these flanges will be local leak rate t'ested after installation and will be included in subsequent Type B local leak rate testing by virtue of their design.
Based on the information discussed above and the fact that each of the penetrations will continue to maintain containment boundary integrity, the staff finds the proposed TS
.change deleting these three RHR valves from Table 3.6.3-1 to be acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendment.
The State official had no comments..
- 5. 0 ENVIRONMENTAL CONSIDERATION The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (60 FR 35083) and (60 FR 36449).
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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- 6. 0 CONCLUSION The Commission has. concluded, based on the considerations discussed
- above, that:
(I) there is reasonable assurance that the 'health and safety oF the public will not be endangered by operation in the proposed
- manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the 'public.
Principal Contributor:
C. Poslusny Date:
September ll, 1995