ML20078C007
| ML20078C007 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 01/20/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20078C005 | List: |
| References | |
| NUDOCS 9501260143 | |
| Download: ML20078C007 (4) | |
Text
i pa ata yw t
UNITED STATES 2
S NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 2065H001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 85 AND 46 TO FACILITY OPERATING LICENSE NOS. NPF-39 AND NPF-85 PHILADELPHIA ELECTRIC COMPANY
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LIMERICK GENERATING STATION. UNITS 1 AND 2 DOCKET NOS. 50-352 AND 50-353 l
1.0 INTRODUCTION
By letter dated July 20, 1994, as supplemented September 23, 1994, the Philadelphia Electric Company (the licensee) submitted a request for changes to the Limerick Generating Station, Units 1 and 2, Technical Specifications (TS). The supplement provided additional information that did not change the initial no significant hazards consideration determination. The proposed changes would revise the Steam Leakage Detection System high area temperature instrument setpoints for the High Pressure Coolant Injection (HPCI) equipment room and Reactor Core Isolation Cooling (RCIC) equipment room. The licensee's objective is to eliminate the HPCI and RCIC systems' dependence on equipment room cooling. This will enable the HPCI and RCIC systems to be considered operable in the event of loss of Emergency Service Water supply to their respective equipment room coolers.
2.0 EVALUATION HPCI and RCIC Steam Leakage Detection System:
Steam lines containing steam at reactor pressure are routed from the main steam system inside containment to the HPCI and RCIC pump turbines located outside the primary containment in the HPCI and RCIC equipment rooms. These steam lines are provided with steam leakage detection instrumentation and containment isolation valves which provide for automatic isolation in the event of a steam line break in the equipment rooms or pipe chase. The leakage detecthn systems (LDSs) are described in FSAR Section 7.6.1.3.3.
The LDS instruments monitor:
(a) equipment room temperatures, (b) equipment area vent air differential temperatures, (c) steam line flow, (d) steam line pressure, (e) pipe chase area temperatures and (f) HPCI and RCIC pump turbine exhaust diaphragm pressures. The selection of monitored variables provides diversity for detection of a wide spectrum of break sizes and locations under various ambient conditions.
It is the (a) and (b) detection sensors that would be affected by the proposed amendment. The LDS provides initiation signals to
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isolation systems as described in FSAR Section 7.3.1.1.2.4.
Automatic 1
isolation ensures that:
(a) in the event of a line break, the radiological dota consequences to the public and to the control room will not exceed acceptable limits and (b) the environmental conditions (temperature, pressure, dynamic forces, flooding, etc.) to which other safety-related systems, structures and equipment are exposed will not render them inoperable.
1 9501260143 950120 PDR ADOCK 05000352 P
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Table 3.3.2-2 of the LGS Technical Specifications specifies the temperature i
detection setpoints and allowable values for the steam leakage detection i
instruments serving the HPCI equipment room and the RCIC equipment room steam j
leakage detection systems.
i Temperature detection alarm setpoints for the HPCI and RCIC equipment rooms
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would not be affected by the proposed amendment.
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, Design Basis for LDS:
Instruments:
NUREG-1433, " Standard Technical i
Specifications - General Electric Plants BWR/4," states that the design basis i
of equipment area leakage detection instruments is to detect steam leakage i
equivalent to 25 gps.
The 25 gpm criterion has been long-used as an assumed 4
j leakage rate when analyzing the design of leakage detection systems for
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secondary containment equipment rooms in BWR facilities.
HPCI and RCIC Equipment Room Cooling: The HPCI and RCIC equipment rooms are j
each provided with two 100% capacity unit coolers, one lead and one standby.
j The RCIC equipment room unit coolers are respectively served by the A loop of j
the Emergency Service Water (ESW) system and the HPCI equipment room coolers.
are served by the B ESW loop. The unit coolers are considered required i
support equipment for the HPCI and RCIC systems because loss of room cooling would result in room temperatures exceeding the conditions for which the HPCI and RCIC systems are environmentally qualified. The cooling systems are described in FSAR Section 9.4.2.2.
The support squipment is safety-grade and
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single active failure proof.
During normal ope <ation the HPCI and RCIC
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equipment rooms are cooled by the Reactor Enclosure Ventilation System with the unit coolers operating automatically as needed, using non-safety related service water, for additional cooling. During accident conditions the unit coolers cool the spaces using emergency service water. The unit coolers are j
designed to maintain the spaces at s120*F.
Loss of ESW supply to the unit coolers requires that the affected HPCI and RCIC systems be declared i
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j Plant Modifications: Modifications to the HPCI system wili allow an increase l
of the EQ temperature qualification from 150*F to 1/PF.
Tne RCIC system will d
be upgraded as necessary for a 155'F temperature qualification. These actions will enable HPCI and RCIC systems to be operable without dependence on the unit coolers. To reflect the higher equipment qualification temperatures, the equipment room high temperature detection instrument setpoints must be raised to preclude the potential for unnecessary system isolations which would degrade the HPCI and RCIC systems reliability under accident conditions when i
the equipment room temperature rises. The modifications are scheduled to be completed prior to the Unit 2 third refueling outage (January 1995).
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TS Changes: The HPCI equipment room high temperature trip setpoint would be 1
increased from 175'F to 225'F, and the allowable value range increased from 3
165'F s T s 175*F to 218'F s T s 247'F. The HPCI equipment room high AT trip setpoint would be increased from 88'F to 126*F, and the allowable value from 588'F to s130.5'F. The RCIC equipment room high temperature trip setpoint would be increased from 175'F to 205'F, and the allowable value range
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1 increased from 165'F s T s 200*F to 198'F s T s 227'F. The RCIC equipment room high AT trip setpoint would be increased from 80*F to 109'F. and the allowable value from 588'F to sll3.5'F.
RCIC and HPCI Area Temperature Profile Analyses: The licensee analyzed the time vs. temperature response profile for the HPCI and RCIC Equipment Rooms assuming a DBA-LOCA with loss of cooling water supply to the unit coolers.
The proposed new temperature setpoints (and environments.1 qualification requirements for HPCI) are based on those analyses. At a meeting with the staff on September 8,1994, the licensee described the analytical methodology.
The Bechtel thermal-hydraulic analysis code PCFLUD was used to model the compartment volumes, heat structures, mass and energy sources and sinks. The 4
i model predicted the resultant time-vs-temperatura responses of the 4
compartments. New EQ limits were established to bound the compartment temperatures, and new LDS setpoints selected to assure that loss of ESW under accident conditions would not alone (in the absence of a steam leak) result in inadvertent isolation of the HPCI or RCIC system.
4 In a letter dated September 23, 1994, the licensee forwarded additional information relating to the PCFLUD code. The letter states that PCFLUD has not been the subject of an independent staff review, but has been reviewed by the staff in the course of other licensing actions. The letter also states that PCFLUD is derived from predecessor codes COPATTA and COPDA which were reviewed and approved by the staff and has been validated and verified.
Based on this information, the staff accepts the licensee's analytical methodology j
for analysis of the HPCI and RCIC Equipment Compartment temperature profile.
j Radiological Concerns: The proposed amendment does not involve any increase in the radiological dose consequences of a Main Steam Line Failure Outside of j
Containment, an analyzed event for which Standard Review Plan Section 15.6.4 specifies acceptable analytical methodology and dose acceptance criteria. The licensee's application states that the limiting break size and location continue to be that of a (much larger) main steam line.
The licensee has performed appropriate analyses to determine the temperature conditions necessary for qualification of HPCI and RCIC systems to operate without the support of the normal and emergency cooling water sources to their equipment rooms. The licensee has also established revised temperature setpoints for the steam leakage detection instruments serving the HPCI and RCIC turbines. The revised setpoints will assure that the LDS vill detect steam line leakage and isolate the turbine in the event a compartment is heated by a steam line break, but will permit continued HPCI or RCIC turbine operation in the event a compartment is heated due to loss of cooling water.
Based on its review, the staff concludes that the licensee's application of July 20, 1994 relating to the Leak Detection System is acceptable.
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3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 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 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 i
exposure.
The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideratiorc, ard there has been no public comment on such finding (59 FR 47178). Accordingly, tha amendments j
meet 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 amendments.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the -
public wd 1 not be endangered by operation in the proposed mar.ner, (2) such activities will be conducted 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:
W. Long Date:
January 20, 1995
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