ML17157A968
| ML17157A968 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 12/02/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17157A967 | List: |
| References | |
| TAC-M81684, NUDOCS 9112130180 | |
| Download: ML17157A968 (5) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 RELATED TO AMENDMENT NO.
ggq TO FACILITY OPERATING LICENSE NO. NPF-14 AMENDMENT NO.
83 TO FACILITY OPERATING LICENSE NO. NPF-22 PENNSYLVANIA POWER Imt LIGHT COMPANY ALLEGHENY ELECTRIC COOPERATIV~E INC.
SUSQUEHANNA STEAM ELECTRIC STATION~UNITS 1 AND 2 DOCKET NOS.
50-387 AND 388 I
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 1.0.
INTRODUCTION By letter dated September 4, 1991, the Pennsylvania Power and Light Company and Allegheny Electric Cooperative, Inc. (the licensees) submitted a request for changes to the Susquehanna Steam Electric Station (SSES), Units 1 and 2, Technical Specifications (TS).
The requested changes would make changes to the Technical Specification 4.5.l.c.2 such that the High Pressure Coolant Injection (HPCI) system is verified to develop a flow of at least 5000 gpm against a test line pressure of greater than or equal to 245 psig when measured at the pump discharge centerline when steam is being supplied to the HPCI turbine at 150
+ 15 psig.
2.0 EVALUATION Technical Specification Surveillance Requirement 4.5.1.c.2 requires verifying that the HPCI system develops a flow of at least 5000 gpm against a test line pressure of 210
+ 15 psig when steam is being supplied to the HPCI turbine at 150
+ 15 psig.
This demonstrates the capability of the HPCI system to inject into the vessel at the lowest system design Reactor Pressure Vessel (RPV) pressure of 150 psig.
The current test line pressure,
- however, does not meet a newly calculated value, of greater than or equal to 245 psig when measured at the pump discharge centerline, for performance testing at low reactor pressure.
This calculation was performed during the licensee's reevaluation of the basis for this test due to the inability to demonstrate the test line pressure requirement during low pressure surveillance testing.
(NRC review of this problem is documented in the SSES, Unit 2, Amendment No. 62.)
The license amendments revise Specification 4.5.1.c.2 such that the HPCI system is verified to develop a flow of at least 5000 gpm against a test line pressure of greater than or equal to 245 psig when measured at the discharge centerline when steam is being supplied to the turbine at 150
+ 15 psig.
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1 Specification 4.5.1.c.2 requires performing a test of the HPCI system at a
nominal steam supply pressure of 150 psig.
The purpose of the test is to demonstrate that the HPCI system is capable of providing 5000 gpm to the RPV when the RPV is nominally at 150 psig.
During startup and power operation an alternate flowpath is used for this test which returns the flow to the Condensate Storage Tank (CST) since actual injection into the RPV is not practical.
In order to meet the test s intent of exhibiting HPCI capability to inject, this CST flowpath must impose a back pressure (i.e. test line pressure) on the HPCI pumps which is equivalent to the pressure the pumps would be pumping against when injecting to a nominal 150 psig RPV.
Currently, the test line pressure is required to be 210
+ 15 psig.
The licensees'alculation, M-HPC-015, revision 2, determined that this pressure should be greater than or equal to 245 psig when measured at the pump discharge centerline with a steam supply pressure of 165 psig.
Implementation of this change will assur e this surveillance test meets its intent by exhibiting that HPCI is capable of injecting 5000 gpm to the RPV when steam is nominally supplied to the HPCI turbine at the full range of allowed test pressures, i.e.,
135 to 165 psig.
The proposed change corrects a potential error in a Technical Specification requirement that conflicts with a recently performed design calculation.
System performance, given the operational conditions of the test, is not in question nor is the safety of the plant.
Under the conditions of the test, the required injection flowrate of 5000 gpm can be achieved with the higher test line pressure.
In addition to the documented surveillance results which show compliance with current Technical Specification requirements for each unit, testing has been performed on Unit 2 which indicates that the system meets the revised requirements (Unit I has been evaluated to also meet these requirements based on similarity with Unit 2 design and performance, and extrapolated test data).
The pressure in question is well below the pressure when the low pressure Emergency Core Cooling System (ECCS) systems become available (initiation signal trip setpoint
= 436 psig).
Meeting the new acceptance criteria for test line pressure continues to prove that the HPCI pumps are capable of achieving rated injection at a nominal steam pressure of 150 psig.
The change addresses a condition where there exists an inadequate basis for a surveillance requirement that is a performance test to demonstrate HPCI operation at the low end of its available operating RPV pressure range.
The change does not affect the capability of the HPCI system to perform its intended design function and does not affect the ability of the plant to deal with a high or low pressure Loss of Coolant Accident (LOCA).
High pressure operation is demonstrated. under a, different surveillance requirement which is unaffected by this change.
While HPCI operation is assumed in the large break accident analysis for reactor pressures down to 150 psig, its contribution to core reflood rate and thus to peak cladding temperatures is small.
The margin of safety maintained by th'is Technical Specification is a function of the operation of all ECCS operating in their prescribed modes.
Protection against a low pressure LOCA is provided by the low pressure ECCS with only a minor contributioh from HPCI under large break LOCA scenarios.
The HPCI system is shown to be capable of providing the required flow at higher pressures by design and periodic test.
Based on the above, the staff finds the proposed change acceptable.
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 and changes surveillance requirements.
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 exposure.
The Commission has previously issued a
proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (56 FR 51927).
Accordingly, the amendments meet eligibility criteria for categorical exclusion set forth in 10 FR 51.22(c)(9).
Pursuant to 10 FR 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 wi 11 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 amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contr ibutor:
James J. Raleigh Date:
December 2,
1991