ML20249B010
| ML20249B010 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 06/16/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20249B007 | List: |
| References | |
| NUDOCS 9806190277 | |
| Download: ML20249B010 (4) | |
Text
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.c. Esses.40M
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SAFETY EVALUATION BY THE OFFG OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS.129 AND 90 TO FACILITY OPERATING LICENSE NOS. NPF-39 AND NPF-85 PHILADELPHIA ELECTRIC COMPANY LIMERICK GENERATING STATION. UNITS 1 AND 2 DOCKET NOS. 50-352 AND 50-353
1.0 INTRODUCTION
By letter dated January 27,~ 1998, the Philadelphia Electric Company (the licensee) submitted a request for changes to the Limerick Generating Station (LGS), Units 1 and 2, Technical Specifications (TSs). The proposed changes remove the maximum isolation time for the high pressure coolant injection (HPCI) turbine exhaust containment isolation valve HV-55-1F072 (LGS, Unit 1) and isolation valve HV-55-2F072 (LGS, Unit 2) from Table 3.6.3-1, "Part A -
Primary Containment isolation Valves," of the LGS, Units 1 and 2 TS, respectively, and add a notation that the isolation time is not required. Both valves cited above will be identified as HV-55-1(2)F072 henceforth in this safety evaluation.
2.0 BACKGROUND
Section 1824 of the Atomic Energy Act of 1954, as amended (the "Act") requires applicants for nuclear power plant operating licenses to include TSs as part of the license. The Commission's regulatory requirements related to the content of TSs are set forth in 10 CFR 50.36. That regulation requires that the TSs include items in five specific categories, including (1) safety limits, limiting safety system settings and limiting control settings; (2) limiting conditions for operation; (3) surveillance requirements; (4) design features; and (5) administrative controls.
The regulation does not specify the particular requirements to be included in the TSs.
The Commission, however, provided guidance for the contents of TSs in its " Final Policy Statement on Technical Specifications improvements for Nuclear Power Reactors," which was published in the Federal Re9ister at 58 FR 39132 (July 22,1993). The Commission indicated therein that compliance with its Final Policy Statement satisfies Section 182a of the Act. Criteria for the content of TSs were subsequently incorporated into 10 CFR 50.36, cf. 60 FR 36953 (July 19,1995). In particular, the Commission indicated that certain items could be removed from the TSs, consistent with the standard enunciated in Portland General Electric Co. (Trojan Nuclear Plant), ALAB-531, 9 NRC 263,273 (1979). In that case, the Atomic Safety and Licensing Appeal Board indicated that " technical specifications are to be reserved for those matters as to which the imposition of rigid conditions or limitations upon reactor operation is deemed necessary to obviate the possibility of an abnormal situation or event giving rise to en L
- immediate threat to the public health and safety."
98061902T7 980616 PDR ADOCK 05000352 P
2-The four critada defined by 10 CFR 50.36 for determining whether a particular matter is required to be included in the TS limiting conditions for operations, are as follows:
(1) installed instrumentation that is used to detect, and indicate in the control room, a L
significant abnormal degradation of the reactor coolant pressure boundary; (2) a process variable, design feature, or operating restriction that is an initial condition of a design basis accident or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier; (3) a structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier; (4) a structure, system, or component which opemting experience or probabilistic risk assessment has shown to be significant to public health and safety.
Existing TS requirements which fall within or satisfy any of the above criteria must be retained in TSs; those requirements which do not fall within or satisfy these criteria may be removed from the TS.
3.0 EVALUATION The maximum isolation time for the HPCI Turbine Exhaust Valve is not a criteria for safety limits delineated in 10 CFR 50.36(c)(1), nor does it meet the criteria for Limiting Conditions for Operation delineated in 10 CFR 50.36(c)(2)(li)(a)-(d).
Removal of specific maximum isolation times and closure stroke _ verification for remote manual isolation valves from the TSs is consistent with improved Standard Technical Specifications (NUREG-1433, Rev.1). Improved Standard TS generic Primary Containment isolation Valves (PCIV) surveillance requirements are limited to verifying isolation stroke times only for PCIVs receiving automatic isolation signals. The safety-related HPCI system operation occurs with valves HV-55-1(2) F072 passively open. In addition, NRC Generic Letter g1-08, " Removal of Component Lists from Technical Specifications," states that "The removal of valve closure times that are included in some plant TS would not alter the TS req 0irement to verify that the valve stroke times are within their limits. Therefore, removal of these ':fosure times is acceptable."
HPCI valves HV-55-1(2)F072 are 12-inch, normally open valves that provide remote manual' isolation to containment penetration 210. The subject valves are not required to respond to any analyzed accidents or transients.
The maximum isolation time is not a structure, system, or componord and is not installed instrumentation. Therefore,10 CFR 50.36(c)(2)(ii)(a), (c), and (d) do not require its inclusion in the TS. With respect to 10 CFR 50 3my?MEMM, emd.t~.T.".4/,74'cr. Qts ti'dwb6 thi+6s is not a safety analysis limit associated with any design basis accident (loss-of-coolant accident / loss-of-offsite power), station blackout or fire safe shutdown analysis. The maximum time established for these valves is based on standard valve design practices and is used to
. establish inservice Test (IST) Program performance ciiteria. The LGS IST program will still
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3-maintain an IST basis maximum time for HV-55-1(2)F072 to satablish action and alert levels for valve performance monitoring. These performance-based values, in conjunction with diagnostic test criteria, are used for motor operated valve (MOV) material condition monitoring and trending.
Therefore, eliminating the subject maximum isolation time requirement from the T8s will not increase tta probability of malfunction of the valves since the principal means of monitoring valve performarue remains unchanged.
These valv6s are capable of performing the remote manual function described in the Safety Analysis Report. Check valves 0551(2)F021, upstream of HV-551(2)F072, function to prevent gross suppression pool water leakage to the HPCI turbine exhaust lines.
Given the assured 30-day water seal and design features of the HPCI system, containment leakage through this valve and associated penetration is not associated with any accident or radiological release analysis. Since the exhaust lines are submerged beneath the minimum
' Suppression Pool water level and the HPCI system is a closed system outside Primary Containment, containment bypass leakage is not a concom.
HV 55-1(2)F072 provide a system design feature to isolate a potential containment leak path.
Any leakage through this path will be monitored and contained in the HPCI pump room. These turbins exhaust lines are classified as a moderate energy fluid system, and a crack in these lines is the only postulated event. Pipe breaks of the applicable piping are beyond design bases.
Leakage of these lines can be remotely isolated from the control room if a pipe crack occurred during normal plant operation. Manual isolation of HV-055-1(2)F072 occurs procedurally when HPCI is no longer needed and when plant parameters indicate there is leakage into the HPCI room. These valves would only be manually closed under events where there was a need to isolate HPCI from suppress:an pool water inventory based on plant indications which are entry conditions for LGS Special Event procedure SE 4-1, " Reactor Enclosure Flooding," LGS Transient Response implementation Plan procedures T-250, " Remote manual Primary Containment Isolations," or T 260, " Reactor Vessel Venting." Each of these procedures may ultimately require isolation of the HPCI turbine exhaust lines by manually closing HV-055-1(2)F072. Given that these procedurally mandated valve isolations are all via remote manual means, valve isolation time is not a critical parameter requiring specif5 acceptance criteria.
The integrity of the suppression pool water supply is ensured by the general plant design of water sealed penetrations both with and without successfulisolation of this single remote manual i
l-Isolation valve. The penetration is water sealed from the containment atmosphere and there is no i
driving force for a water leak without containment being pressurized. This is the expected condition under which LGS Special Event procedure SE 4-1, " Reactor Enclosure Flooding,"is entered. Following an accident when HPCI is no longer needed, containment may be slightly pressurized to 10 psig or less, causing suppression pool water to press into the HPCI exhaust line. Check valves 0551(2)F021 provide the normal and immediate leakage barrier. A gross
' release of suppression pool water is prevented by HV-551(2)F072 and 55-1(2)F021 check valves, intact HPCI exhaust lines, or ultimately by the containment of water within the HPCI -
room.
Based on thibiairs evaluation set forth above, the proposed removal of the maximum isolation
' time for valves HV-55-1(2)F072 from Table 3.6.3-1 of the LGS TSs does not meet the 10 CFR
' 50.36 criteria and is, therefore, acceptable.
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4.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Pennsylvania State official wr,s notified of the proposed issuance of the amendments. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change 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 amendments involve no significant increase in the amounts, and no significant ch9nge 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 I
a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (63 FR 11921). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
6.0 CONCLUSlQB The Commission has concluded, based on the considerations discussed above, that: (1) 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 conds ted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: B. Buckicy Date: - June 16, 1998 t
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