ML16138A813
| ML16138A813 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/15/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML16138A814 | List: |
| References | |
| NUDOCS 9604170333 | |
| Download: ML16138A813 (3) | |
Text
UNITED STATES 0
NUCLEAR REGULATORY COMMISSION 0
WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 216 TO FACILITY OPERATING LICENSE DPR-38 AMENDMENT NO. 216 TO FACILITY OPERATING LICENSE DPR-47 AND AMENDMENT NO. 213 TO FACILITY OPERATING LICENSE DPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS 1. 2. AND 3 DOCKET NOS. 50-269, 50-270, AND 50-287
1.0 INTRODUCTION
By letter dated December 7, 1995, Duke Power Company, (the licensee),
submitted a request for changes to the Oconee Nuclear Station, Units 1, 2, and 3, Technical Specifications (TS). The requested changes would revise TS 3.4.2 and TS Table 4.1-1 of the Secondary Decay Heat Removal TS to delete the requirement of having the main feedwater pump discharge header pressure switch provide an input to actuate the Anticipatory Reactor Trip System (ARTS) and Emergency Feedwater System (EFDW).
2.0 BACKGROUND
The ARTS sub-system was added to the Reactor Protection System (RPS) in 1980 in response to NRC IE Bulletin 79-05B and NRC Commission orders. The ARTS sub-system monitors main feedwater and main turbine-generator parameters to provide anticipatory reactor shutdown following a loss of all main feedwater or a main turbine-generator trip.
The primary purpose of the ARTS is to reduce challenges to the pressurizer Power Operated Relief Valves (PORVs), to lift and then reset following a loss of main feedwater or a main turbine-generator trip transient.
Both the main feedwater pump turbines and the main turbine-generator trips provide input to the ARTS via low trip oil pressure. Also, there is an input to the ARTS from main feedwater pumps low pump discharge header pressure.
The Emergency Feedwater System (EFDW) is designed to start automatically in the event of loss of main feedwater pumps as sensed by either:
Main Feedwater Pumps Tripped (Control Oil pressure below 75 psig)
Main Feedwater Pumps Discharge Pressure below 800 psig Main Turbine-Generator Tripped (Emergency Trip Header Oil Pressure below 800 psig), or Low water level in either steam generator for 30 seconds.
9604170333 960415 PDR ADOCK 05000269 P
-2 3.0 EVALUAION The licensee proposes to remove the anticipatory reactor trip and emergency feedwater actuation signal from loss of main feedwater pumps,sensed by feedwater discharge pressure of less than 800 psig. The low feedwater discharge header pressure switches inputs would be removed from both ARTS and EFDW in order to:
Eliminate the D Heater Drain Pumps (HDPs) discharge pressure from preventing the main feedwater discharge pressure switches from providing input to the ARTS and EFDW systems. After Unit 3 tripped from a loss of feedwater, the D HDPs maintained a 770 psig pressure in the dead headed main feedwater discharge header. Therefore, the original pressure switch setpoint of 750 psig was not reached and there was no input to either ARTS or EFDW for a loss of main feedwater. (Reported by Licensee Event Report 91-009-00 and 91-009-01)
Preclude spurious reactor trips during pressure switch calibration, Maintain a design similar to all other B&W design plants, and Save approximately $300,000 over the life of the plant.
The justification for removing the low feedwater pump discharge pressure switches as inputs to ARTS and EFDW, is that another diverse input is provided. This diverse input is the detection of the main feedwater pumps tripped (control oil pressure below 75 psig).
After the TMI-2 incident, the NRC required all B&W plants to increase the reactor coolant pressure setpoint for lifting the PORVs and lower the pressure setpoint for tripping the reactor. These reactor coolant pressure setpoint changes also reduced the probability of challenging the PORVs. The main turbine-generator trip (Emergency Trip Header Oil Pressure below 800 psig) and the main feedwater pumps tripped (control oil pressure below 75 psig) input to ARTS will acceptably reduce the probability of challenging the PORVs. Further diverse input to EFDW is provided by:
Main Turbine-Generator Tripped (Emergency Trip Header Oil Pressure below 800 psig), or Low water level in either steam generator for 30 seconds.
4.0 STAFF CONCLUSION Based on our review of the licensee's request to remove the main feedwater pump discharge header pressure switch inputs to the ART and EFDW actuation, the staff concludes that sufficient diversity is provided to assure that the probability of challenging the PORVs is not changed and the EFDW system is not adversely affected. Therefore, this TS change is acceptable.
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5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the South Carolina State official was notified of the proposed issuance of the amendments. The State official had no comments.
6.0 ENVIRONMENTAL CONSIDERATION
The amendments change requirements 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 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 (61 FR 1628 dated January 22, 1996).
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 environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
7.0 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 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 amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: F. Paulitz Date:
April 15, 1996