ML20058P433
| ML20058P433 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 08/13/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20058P431 | List: |
| References | |
| NUDOCS 9008170042 | |
| Download: ML20058P433 (2) | |
Text
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i SAFETY EVALUATION.BY.THE.0FFICE-OF NUCLEAR. REACTOR. REGULATION l
ATWS.RECTRCULATION. PUMP TRIP. SYSTEM. DESIGN MODIFICATION POWER AUTHORITY.0F THE STATE OF NEW. YORK l
FITZPATRICK NUCLEAR. POWER PLANT DOCKET.NO. 50-333 INTRODUCTION By letter ' dated April 23, 1990, the Power Authority of the State of New York (licensee) provided additional information regarding implementation of the ATWS Rule at the FitzPatrick Nuclear Power Plant. This additional information is in response to the staff's concerns on the Recirculation Pump Trip (RfT) System potential inadvertent actuation and provisions for testability during normal plant operation.
EVALUATION The modified RPT system is designed to backup the Reactor Protection System (RPS) in the event of an anticipated transient without scram (ATWS) event and will trip both reactor recirculation pumps on high reactor pressure or low reactor water level. The actuation logic is a one-out-of-two-taken-twice from i
pressure signals or a one-out-of-two-taken-twice from level signals. When energized, the logic trips both motor-generator feeder breakers for the recirculation pumps. The RPT circuitry shares the existing hardware used by the Alternate Rod Injection (ARI) System up to and including isolation relays.
The spare contacts of the ARI isolation relay are used to provide the logic to energize the relays which cause the recirculation pump motor generator (MG) set feeder breakers to open, tripping the associated recirculation pump.
The design has been modified to permit maintenance repairs, test or calibration of system logic and instrumentation up to, but not including the fin 61 ARI valves and RPT MG feeder breaker shunt trip actuating relays. To test the ARI/RPT circuitry, a new five position switch was installed.
Each individual level and pressure instrument is testable during plant operation without initiating the ARI/RPT System since two pressure or level signals must be present to complete the logic requirement.
The test switch eliminates the need to use jumpers during testing.
When the test switch is turned to a specific channel, an indicating light is turned on to indicate that the system is under test. When the test is complete, the test procedure requires that the system be returned to normal by the technicians and verified by a licensed operator.
4 ADOCN c50co333 p
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2 CONCLUSION The design has been reviewed by the staff and the determination made that the nodified RPT logic design and the ARl/RPT logic testing features conform to the requirements of 10 CFR 50.62, and is, therefore acceptable. This conclusion issupportedbythepost-implementationinspectlenwhichhasbeenperformedat the FitzPatrick Plant using temporary instruction T12500/20, " Inspection To Determine Compliance with ATWS Rule, 10 CFR 50.62" (which is documented in Inspection Reports 50-333/88-29,89-08,and90-04).
However, the staff requests that the plant Technical Specification Table 3.2-7,
" Instrumentation that initiates Recirculation Pump Trip," be updated to reflect the RPT System logic change. The requested change would modify the nunber of operable instrument channels required per trip system and the Action statement so that compensatory measures are taken prior to complete loss of the RPT function. As presently written, no action is required by the technical specifications unless the minimum number of operable instrument channels per trip system is reduced to zero. At this point, the RPT System is incapable of tripping the recirculation pumps since actuation requires energizing of the relay.
This is undesirable since the purpose of the RPT System is to provide a backup feature to the RPS.
It is requested that the action statement and appropriate Limiting Condition for Operation, therefore, be modified to follow the guidelines of the Standard Technical Specifications and start with loss of any one of the two instrumer,t channels in a trip system.
The FSAR should also be updated as appropriate to document this modification.
Dated: