ML20128N844
| ML20128N844 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 07/12/1985 |
| From: | DUQUESNE LIGHT CO. |
| To: | |
| Shared Package | |
| ML20128N703 | List: |
| References | |
| NUDOCS 8507260283 | |
| Download: ML20128N844 (4) | |
Text
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9 ATTACHMENT A Revise Appendix A as follows:
Remove Pages Insert Pages 3/4 2-8 3/4 2-8 3/4 2-9a None B3/4 2-5 B3/4 2-5
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POWER DISTRIBUTION LIMITS N
NUCLEAR ENTHALPY HOT CHANNEL FACTOR - FaH LIMITING CONDITION FOR OPERATION N
3.2.3 F
shall be limited by the following relationship:
H N
F3H I 1.55 [1 + 0.3 (1-P)]
l where P THERMAL POWER
=
RATED THERMAL POWER APPLICABILITY:
MODE 1 ACTION:
N With F exceeding its limit:
aH Reduce THERMA'L POWER to less than 50% of RATED THERMAL POWER within a.
2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and reduce the Power Range Neutron Flux-High Trip Setpoints to 2 55% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, N
b.
Demonstrate thru in-core mapping that F is within its limit within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after exceeding the limit or Nduce THERMAL POWER to less than 5% of RATED THERMAL POWER within the next 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, and c.
Identify and correct the cause of the out of limit condition prior to increasing THERMAL POWER, subsequent POWER OPERATION may proceed provided that F is demonstrated through in-core mapping to be H
within its limit at a nominal 50% of RATED THERMAL POWER prior to exceeding this THERMAL power, at a nominal 75% of RATED THERMAL POWER prior to exceeding this THERMAL power and within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after attaining 95% or greater RATED THERMAL POWER.
BEAVER VALLEY - UNIT 1 3/4 2-8 PROPOSED WORDING
t s
POWER DISTRIBUTION LIMITS BASES Fuel rod bowing reduces the value of the DNB ratio.
Credit is available to offset this reduction in the generic margin.
The generic design margins, totaling 9.1% DNBR, and completely offsets any rod bow penalties (< 3% for the worst case which occurs at a burnup of 33,000 MWD /MTU).
This margin includes the following:
1.
Design Limit DNBR of 1.30 vs. 1.28 GridSpacing(K 2.
ThermalDiffusi8n)of0.046vs.0.059 3.
Coefficient of 0.038 vs. 0.059 4.
DNBR Multiplier of 0.865 vs. 0.88 5.
Pitch reduction The radial peaking factor Fxy (Z) is measured periodically to provide assur-ance that the hot channel factor, Fq (Z), remains within its limit. The Fxy limit for Rated Thermal ' Power (FRTP) as provided in tne Radial Peaking Factor x
Limit Report per specification 6.9.1.14 was determined from expected power control maneuvers over the full range of burnup conditions in the core.
3/4.2.4 QUADRANT POWER TILT RADIO The quadrant power tilt ratio limit assures that the radial power distribution satisfies the design values used in the power capability analysis.
Radial power distribution measurements are made during startup testing and period-ically during power operation.
The limit of 1.02 at which corrective action is required provides DNB and linear heat generation rate protection with x-y plane power tilts.
The two-hour time allowance for operation with a tilt condition greater than 1.02 but less than 1.09 is provided to allow identification and correction of a dropped or misaligned rod.
In the event such action does not correct the tilt, the margin for uncertainty on F is reinstated by reducing the maximum q
allowed power by 3 percent for each percent of tilt in excess of 1.0.
BEAVER VALLEY - UNIT 1 B 3/4 2-5 PROPOSED WORDING L
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ATTACHMENT B No Significant Hazard Determination Proposed Change Request No.110 amends the Beaver Valley Power Station, Unit No. 1 Technical Specifications Appendix A by deleting the rod bow penalty applied to the enthalpy rise hot-channel factor.
Description of amendment request:
The proposed amendment would revise Section 3.2.3, Nuclear Enthalpy Hot Channel Factor, F(N,aH) by deleting the rod bow penalty multiplier [1-RBP(BU)].
The results of studies published in NRC approved WCAP-8691 Revision 1 provide a methodology for removing the rod bow penalty applied to F(N,aH) and in its place applying a Rod Bow Power Peaking Factor uncertainty F(B,Q) to the Heat Flux Hot Channel Factor F(N,Q).
Figure 3.2-4 Rod Bow Penalty as a Function of Burnup is then no longer applicable and can also be deleted.
Bases Section 3/4.2.2 and 3/4.2.3 Heat Flux and Nuclear Enthalpy Hot Channel Factors has been revised to provide the basis for removing the rod bow penalty applied to F(N,aH) and specifies that credit is available in the generic design margin to completely offset the rod bow penalty.
Changes to be incorporated into the UFSAR are attached for your information and will be included in the update following approval of this amendment.
Basis for proposed no significant hazards consideration determination:
The Comission has provided guidance concerning the application of standards for determining whether a significant hazards consideration exists by providing certain examples (48 FR 14870).
One of these, Example (Vi),
involving no significant hazards consideration is a change resulting from the application of a small refinement of a previously used calculational model or design method.
The requested change matches this example since the rod bow calculational model has been refined by the NRC acceptance of the methodology provided in WCAP-8691 Revision 1.
The methodology provides a basis for removing the rod bow penalty applied to F(N,AH) by the use of a Rod Bow Power Peaking Factor uncertainty F(B,Q).
This is then statistically combined with the Nuclear Power Distribution uncertainty F(U,N) and the Engineering Hot Channel Factor F(E,Q), to yield a new total Heat Flux Hot Channel Factor uncertainty F(U,Q) with a maximum value of 1.069 (WCAP-8691 Revision 1 Section 6.1).
This value is the maximum required total peaking factor uncertainty, including the affects of rod bow (WCAP-8691 Revision 1 Section 7).
However, the total uncertainty actually applied to F(N,Q) is a value of 1.08, therefore, the affects of rod bow are accomodated within the available generic design margins.
As a result, no rod bow penalty on F(N,aH) is required since the rod bow affects are accounted for in the uncertainty applied to F(N,Q).
Therefore, based on the above example, it is proposed to characterize the change as involving no significant hazards consideration.