ML20215D444
| ML20215D444 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 12/10/1986 |
| From: | SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | |
| Shared Package | |
| ML20215D418 | List: |
| References | |
| NUDOCS 8612160364 | |
| Download: ML20215D444 (3) | |
Text
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ATTACHMENT I.Page 1 of 2 1
POWER DISTRIBUTION LIMITS 3/4.2.2 HEATFLUXHOTCHANNELFACTOR-FK LIMITING CONDITION FOR OPERATION
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3.2.2 F (Z) shall be limited by the following relationships:
A 2.23 F (Z) 1
] [K(Z)] for P > 0.5 q
4.6 F (Z) 1 [/4.
] [K(Z)] for P 10.5 q
where P _ THERMAL POWER and K(Z) is the function obtained from Figure 3.2-2 for a given core height location.
APPLICABILITY: MODE 1.
ACTION:
With F (Z) exceeding its limit:
q a.
Reduce THERMAL POWER at least 1% for each 1% F (Z) exceeds the
/
o limit within 15 minutes and similiarly reduce the Power Range
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Neutron Flux-High Trip Setpoints within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />; POWER OPERATION may proceed for up to a total of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; subsequent POWER OPERATION may proceed provided the Overpower delta T Trip Setpoints have been reduced at least 1% for each 1% F (Z) exceeds the limit.
O b.
Identify and correct the cause of the out of limit condition prior to increasing THERMAL POWER above the reduced limit required by a, above; THERMAL POWER may then be increased provided F (Z) is demon-strated through incore mapping to be within its limitq 8612160364 861210 DR ADOCK 05000395 PDR SUMER - UNIT 1 3/4 2-4
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ATTACHMENT I Page 2 of 2 3/4.2 POWER DISTRIBUTION LIMITS BASES The specifications of this section provide assurance of fuel integrity during Condition I (Normal Operation) and II (Incidents of Moderate Frequency)
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events by:
(a) maintaining the minimum DN8R in the core greater than or equal to 1.30 during normal operation and in short ters transients, and (b) limiting the fission gas release, fuel pellet temperature and cladding mechanical properties to within assumed design criteria.
In addition, limiting the peak linear power density during Condition I events provides assurance that the initial conditions assumed for the LOCA analyses are met and the ECCS acceptance criteria limit of 2200*F is not exceeded.
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The definitions of certain hot channel and peaking factors as used in these specifications are as follows:
F (Z)
Heat Flux Hot Channel Factor, is defined as the maximum local 0
heat flux on the surface of a fuel rod at core elevation Z divided by the average fuel rod heat flux, allowing for manufacturing tolerances on fuel pellets and rods.
Fh Nuc1' ear Enthalpy Rise Hot Channel Factor, is defined as the ratio of the integral of linear power along the rod with the highest integrated power to the average rod power.
Fxy(Z)
Radial Peaking Factor, is defined as the ratio of peak power density
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to average power density in the horizontal plane at core elevation Z.
3/4.2.1 AXIAL FLUX DIFFERENCE ThelimitsonpIALFLUXDIFFERENCE(AFD)assurethattheF(Z)upperbound q
envelope of 2[tfad khe normalized axial peaking factor is not exceeded during either normal operation or in the event of xenon redistribution following power changes.
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Target flux difference is determined at equilibrium xenon conditions.
The full length rods may be positioned within the core in accordance with their respective insertion limits and should be inserted near their normal position for steady state operation at high power levels.
The value of the target flux difference obtained under these conditions divided by the fraction of RATED THERMAL POWER is the target flux difference at RATED THERMAL POWER for the
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associated core burnup conditions. Target flux differences for other THERMAL POWER levels are obtained by multiplying the RATED THERMAL POWER value by the appropriate fractional THERMAL POWER level.
The periodic updating of the target flux difference value is necessary to reflect core burnup considerations.
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SUMMER - UNIT 1 8 3/4 2-1 i
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SIGNIFICANT HAZARDS DETERMINATION 1.
Does the proposed change involve a significant increase in the probability or consequences of an accidentpreviously evaluated?
No physical plant change is being made, therefore, the probability of accidents previously evaluated will not be increased.
Per WCAP-9272, a max, Fo times Power vs core height is limiting for Fo sensitive accidents. Therefore, reducing the Fo limit from 2.32 to 2.25 provides added assurance that the Fo sensitive accident consequences will be less limiting than those currently in the FSAR. The accident consequence margin created can be used to offset other plant changes such as additional SG tube plugging.
2.
Does the proposed change create the possibility of a new or different kind of accident from any accidentpreviously evaluated?
No physical plant change is being made; therefore, no additional possibility of a new or different kind of accident from any accident previously evaluated has been created.
3.
Does the proposed change involve a significant reduction in a margin of safety?
The Foreduction imposes a more limiting surveillance criteria.
Currently, all safety limits / criteria are met assuming a FQ to less than or equal to 2.32. Therefore, by limiting Fo to less than or equal to l
2.25, one assures that Fo sensitive accident consequences will be less limiting than those in the FSAR. The margin of safety is thus increased with no other plant change. This increased margin could be used to j
offset other penalties, such as higher levels of SG tube plugging.
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