ML20217G598
| ML20217G598 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 07/29/1997 |
| From: | CENTERIOR ENERGY |
| To: | |
| Shared Package | |
| ML20217G596 | List: |
| References | |
| NUDOCS 9708070318 | |
| Download: ML20217G598 (1) | |
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Docket Number 50 346 License Number NPF.3 Attachment 1,lhilTING SAFETY SYSTliht SETTINOS llMES The AXIAL POWER lhtBALANCE tsundaries are established in order to prevent reactor thennal limits from being exceeded. These thermal limits are either power peaking kW/fi limits or DNBR limits. The AXIAL POWER lh1 BALANCE reduces the power level trip produced by a flux to flow ratio such that the boundaries of the figure in the CORE OPERATING LlhilTS REPORT are produced.
RC Pressure - Low. Ilich. and Pressure Temperature The high and low trips are provided to limit the pressure range in which reactor operation is permitted.
During a slow reactivity insertion startup accident from low power or a slow reactivity insertion from high power, the RC high pressure setpoint is reached before the high flux trip setpoint. The trip setpoint for RC high pressure,2355 psig, has been established to maintain the system 3ressure below the safety limit,2750 psig, for any design transient. The RC high pressure trip is sacked up by the pressurizer code safety valves for RCS over pressura protection, and is therefore set lower than the set pressure for these valves, s.2fl5 2525 psig. The RC high pressure trip also backs up the high flux trip.
The RC low pressure,1900.0 psig, and RC pressure-temperature (16.00 T 7957.5) psig, trip setpoints have been established to maintain the DNB ratio greater than or equal to the minimum allowable DN13 ratio for those design accidents that result in a pressure reduction. It also prevents reactor operation at pressures below the valid range of DNB correlation limits, protecting against DNB.
Ilich Flux / Number of Reactor Coolant Pumns On in conjunction with the flux Aflux/ flow trip the high flux / number of reactor coolant pumps on trip prevents the minimum core DNDR from decreasing below the minimum allowable DNB ratio by tripping the reactor due to the loss of reactor coolant pump (s). The pump monitors also restrict the power level for the number of pumps in operation.
DAVIS-BESSE, UNIT 1 B 2-6 Amendment No.23,45,60,61,149,189, 970007031t3 970729 PDR ADOCK 05000346 P
PDR s
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