ML20042F959
| ML20042F959 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 05/07/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20042F956 | List: |
| References | |
| NUDOCS 9005100224 | |
| Download: ML20042F959 (3) | |
Text
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jcrogDo UNITED STATES fy jfgg NUCLEAR REGULATORY COMMISSION
- 8 WASHINGTON. D. C. 20666 g
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION-RELATED TO AMENDMENT NO. 29 TO FACILITY OPERATING LICENSE NO. NPF-58 l
THE CLEVELAND ELECTRIC ILLUMINATING COMPANY. ET AL._
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PIRRY NUCLEAR POWER PL. ANT. UNIT NO. 1 DOCKET NO. 50-440 l
1.0 INTRODUCTION
TheClevelandElectricIlluminatingCompany(CEI)requestedalicense amendmenttoTechnicalSpecificationTables(3.3.1-1and3.3.4.2-1)andthe related Bases (Sections 2.2.1.10 and 2.2.1.11) for the Perry Nuclear Power Plant, Unit 1 by letter dated May 20, 1988 as supplemented November 27, 1989. The proposed amendment would revise notes to Technical Specifications Tables 3.3.1-1 and 3.0.4.2-1 and the Bases Section 2.2.1-10 and 2.2.1-11 to revise the First Stage Turbine Pressure Setpoints based on test data. The existing values were based on turbine thennal heat balance calculations, and the licensees determined through testing that these values have been shown to be overly conservative. The current requirement that the turbine valve closure scrams should be bypassed below the turbine first stage pressure equivalent to 40% of rated thermal power (RTP) remains unchanged.
The proposed Setpoints and Allowable Values were established based on data determined by startup testing. The bases for reducing the setpoints due to reduced feedwater temperature also remains unchanged.
In the proposed change the Setpoints and Allowable Values would be. depicted in terms of actual turbine.first stage pressure, rather than as a percentage of the Turbine Control Valve wide-open position. The actual pressure is more accurately meaningful to measure RTP.
2.0 EVALUATION Turbine First-Stage Pressure has been historically used as the sarameter to approximate reactor power and effect the actual trip bypass. Tae Reactor Protection System (RPS) design purposely chooses this parameter, as opposed to the more direct measurement of power such as neutron flux, in order to assure diversity between the Turbine Stop Valve Closure (TSVC).and Turbine
~ Control Valve Fast Closure (TCVFC) scram functions and the neutron flux scram function.
Four pressure sensors are connected to the high pressure turbine via instrument lines to monitor either turbine bowl pressure or turbine first stage shell pressure. The choice is dependent upon characteristics of turbine operation. The pressure being monitored varies essentially linearly with turbine throttle flow over the full range of turbine operation.
9005100224 90o397 gDR ADOCK 05000440 PDC
1 The turbine first stage pressure sensors are used for an indirect measure-ment of reactor power. They provide an automatic bypass of the TSVC and TCVFC reactor scram and End-of-Cycle Recirculation Pumps Trip functions at low reactor power levels where an immediate scram from closed or closing turbine valves is not required. The trip bypass is in effect whenever turbine first stage pressure is below a specified value, and thus permits continued reactor operation below that setpoint with the turbine stop valves and/or turbine control valve closed.
In the event of inadequate turbine bypass capacity or failure of the turbine bypass system, adequate reactor protection is provided by the diverse high reactor dome pressure or high neutron flux scram functions.
The proposed change is based on test data which provided the actual value of Turbine First Stage Pressure equivalent to 40% rated themal power. The Setpoints and Allowable Values were calculated for norma' yeration and for reduced feedwater heating operation. The purpose of this atpoint is to establish when a turbine trip will cause an anticipatory reactor trip, and an end-of-cycle recirculation pump trip as described in various sections of the Updated Safety Analysis Report.
Turbine first stage pressure is used to sense power since this pressure increases approximately linearly pro 3or-tional with power.
The existing technical specifications have establisied the Setpoint and Allowable Value as a percentage of calibration span of the existing instruments. The proposed Setpoint and Allowable Value are in units of pressure.
In both cases the Setpoint and Allowable Value are based on 40% of rated thermal power. The licensee performed testing during the Startup Testing Program which provided actual data for First Stage Pressure at 40% of rated thermal power. Theproposedsetpointof212psig(corresponding to29.5%)fornormalfeedwaterheatingconditions,versusthecurrent L
setpoint-of 25.4% of span, provides additional margin against inadvertent l
-scrams at low power, while still providing for initiation of the turbine i
stop and control valve closure ' anticipatory reactor scrams and the end-of-cycle l
recirculation pump trip functions prior to exceeding'40% of rated power.-
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The basis for establishing tne Trip Setpoint and Allowable Values (40% of ratedthermalpower)hasnotchanged. Test data has accurately determined the value of turbine first stage pressure equivalent to 40% of rated thermal power. The Trip Setpoint and Allowable Value are being changed based on this test data. The staff hr.s determined that the proposed change more l
accurately represents the Setpoint and Allowable Value for turbine first l
stage pressure and, therefore, it is acceptable, l.
3.0 ENVIRONMENTAL CONSIDERATION
Pursuant to 10 CFR 51.21, 51.32, and 51.35 an Environmental Assessment and finding of No Significant Impact has been prepared and published in the u
FEDERAL REGISTER on May 7,1990(55FR18990). Accordingly, based on the environmental assessment, tne Connission has determined that the issuance of the amendment will not have a significant effect on the quality of the human environment,
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4.0 CONCLUSION
The staff 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, _and (2) such activities will be conducted in compliance with the Commission's regulations and the l
issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
S. Rhow, NRR/SICB Dated: May 7, 1990 1
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