ML20207M517
| ML20207M517 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 01/08/1987 |
| From: | SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | |
| Shared Package | |
| ML20207M491 | List: |
| References | |
| NUDOCS 8701130200 | |
| Download: ML20207M517 (4) | |
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TABLE 2.2-1 (continued)
E REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS Total 5
Functional Unit Allowance (TA)
Z S
Trip Setpoint Allowable Value c
w 18.
Safety Injection Input '
NA NA NA NA NA p
g from ESF 7
19.
Reactor Trip System
-4 Interlocks g io g Q.
g ggsg A.
Intermediate Range NA NA NA 11 x IG '"
p; 16 x-W
{A-Neutron Flux, P-6
/-/
NO B.
Low Power Reactor Trips Block, P-7 g
a.
P-10 input 7.5 4.56 0
P-13 input 7.5 4.56 0
<10% turbine
<12.2% of turbine e
ao impulse pressure impulse pressure equivalent equivalent g
so og
.ogg C.
Power Range Neutron 7.5 4.56 0
138% of RTP 140.2% of RTP oO g
Flux P-8 gge D.
Low Setpoint Power 7.5 4.55 0
(*
on Range Neutron Flux, P-10 b
I E.
Turbine Impulse Chamber 7.5 4.56 0
<10% turbine
<12.2% turbine E
Impulse pressure pressure equivalent Pressure, P-13 equivalent 5
F.
Power Range Neutron 7.5 4.56 0
5 Flux, P-9 i
?*
20.
Reactor Trip Breakers NA NA NA NA NA z
Y 21.
Automatic Actuation Logic NA NA NA NA NA l
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LIMITING SAFETY SYSTEM SETTINGS BASES Intermediate and Source Range, Nuclear Flux (Continued) uncontrolled rod cluster control assembly bank withdrawal from a subcritical condition.
These trips provide redundant protection to the low setpoint trip of the Power Range, Neutron Flux channels.
The Source Range channels will initiate a reactor trip at about 10+5 counts per second unless manually blocked-when P-6 becomes active.4 The Intermediate Range channels will initiate a reactor trip at+c.c. a,Wi-:1 ; W C t te approximately 25 percent of RATED THERMAL POWER unless manually blocked when P-10 becomes active.
Overtemperature AT IE b
The Overtemperature delta T trip provides core protection to prevent DNB for all combinations of pressure, power, coolant temperature, and axial power distribution, provided that the transient is slow with respect to piping transit delays from the cora to the temperature detectors (about 4 seconds),
and pressure is within the range between the Pressurizer high and low pressure trips.
The setpoint is automatically varied with 1) coolant temperature to correct for temperature induced changes in density and heat capacity of water and includes dynamic compensation for piping delays from the core to the loop temperature detectors, 2) pressurizer pressure, and 3) axial power distribution.
With normal axial power distribution, this reactor trip limit is always below the core safety limit as shown in Figure 2.1-1.
If axial peaks are greater than design, as indicated by the difference between top and bottom power range nuclear detectors, the reactor trip is automatically reduced according to the notations in Table 2.2-1.
Overpower AT The Overpower delta T trip provides assurance of fuel integrity (e.g., no fuel melting and less than 1 percent cladding strain) under all possible overpower conditions, limits the required range for Overtemperature delta T protection, and provides a backup to the High Neutron Flux trip. The setpoint is automatically varied with 1) coolant temperature to correct for temperature induced changes in density and heat capacity of water, and 2) rate of change of temperature for dynamic compensation for piping delays from the core to the loop temperature detectors to ensure that the allowable heat generation rate (Kw/ft) is not exceeded.
The overpower AT trip provides protection to mitigate the consequences of various size steam breaks as reported in WCAP 9226, " Reactor Core Response to. Excessive Secondary Steam Break."
Pressurizer Pressure In each of the pressure channels, there are two independent bistables, each with its own trip setting to provide for a high and low pressure trip thus limiting the pressure range in which reactor operation is permitted.
The low setpoint trip protects against low pressure which could lead to DNB by tripping the reactor in the event of a loss of reactor coolant pressure.
SUMER - UNIT 1 B 2-5
e INSERT A The purpose of the P-6 setpoint, which is above the lower end of the intermediate range scale,is to give the operators sufficient time to actuate the source range reactor trip block.
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ATTACHMENT II NO SIGNIFICANT HAZARDS DETERMINATION Based on the following evaluation, SCE&G has determined the proposed change does not involve a significant hazards consideration.
- 1) Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated? NO The proposed chan ge is an administrative change only. No setpoints are being changed. The P-6 ':. rip Se,tpoint and Allowable Setpoint are being converted from current (amps) to the equivalent % indication.
- 2) Does the proposed change create the possibility of a new or difTerent kind of accident from any accident previously evaluated?
NO The p,roposed change is an administrative change and does not change the actual setpoints.
- 3) Does the proposed change involve a significant reduction in a margin of safety?
NO The proposed change is an administrative change and does not change the actual setpoints.
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