ML20236Y466
| ML20236Y466 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 12/07/1987 |
| From: | DUQUESNE LIGHT CO. |
| To: | |
| Shared Package | |
| ML20236Y414 | List: |
| References | |
| NUDOCS 8712140012 | |
| Download: ML20236Y466 (9) | |
Text
.
ATTACHMENT A
1 Revise the Technical Specifications as follows:
'RemcVe Page Insert Page 3/4 2-3 3/4 2-3 l
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i 8712140012 871207 PDR ADOCK 06000334 P
PDR 1
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4 POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS (Continued) 4.2.1.3 The target flux difference of each OPERABLE excore channel shall be determined by measurement at least once per 92 Effective Full Power Days.
The provisions of Specification 4.0.4 are not applicable.
4.2.1.4 The target flux difference shall be updated at least once per 31 Effective Full Power Days be either determining the target flux difference. pursuant to 4.2.1.3 above or by linear interpolation between the most recently measured value and the design end-of-cycle value.
The provisions of Specification 4.0.4 are not applicable.
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BEAVER VALLEY - UNIT 1 3/4 2-3 PROPOSED WORDING
ATTACHMENT B
Safety Analysis Proposed Technical Specification Change No. 141 Description of amendment request:
The proposed amendment would revise surveillance requirement 4.2.1.4 to require determination of the target flux difference by interpolating to the design end-of-life value.
The current surveillance requirement 4.2.1.4 provides for update of the target flux difference at least once per 31 days by either measurement in accordance with 4.2.1.3 or by linear interpolation between the most recently measured value and 0% at the end-of cycle life.
Surveillance requirement 4.2.1.3 provides for update of the target flux difference by measurement at least once per 92 days.
The measurement method requires full power equilibrium Xenon, all rods out condition, with little or no rod movement for at icast 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.
The equilibrium conditions are difficult to maintain for the required 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> period due to plant operating conditions such as startups, j
shutdowns, extended reduced power or load swings.
Therefore, the proposed change is requested to allow improved plant operation by using a
more accurate method for determining the target flux difference whenever a measurement update is not possible.
The target flux difference obtained by interpolating to the design end-of-life value will more closely reflect the actual core conditions and will aid the operators. in maintaining reactor operation within the 1 7%
target band.
To illustrate this point Table 1 and Table 2 have been developed to compare the target flux difference obtained by each method applicable to Cycle 5 and Cycle 4 operating information.
The table parameters are described as follows:
PARAMETER DESCRIPTION 4
Burnup (MWD /MTU)
Core burnup at which the target flux difference is applicable.
1 Measured Target Target flux difference measured at the specified burnup.
Interpolated to Target flux difference determined by interpolation zero to a
target flux difference value of zero at end-of-cycle life.
% Difference Difference between the measured target flux difference value and the target flux difference determined by interpolation to zero at end-of-cycle life.
Interpolated to Target flux difference value determined by inter-Design EOL polation to the design target flux difference value at end-of-cycle life.
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% Difference Difference between the measured target flux difference value and the target flux difference determined by interpolation to zero at end-of-cycle life.
Attachment B
- Page 2 These values have been graphed in Figure 1 and Figure 2 for comparison for the target flux difference data for the measured, interpolation to zero and interpolation to design at EOL values.
As can be
- seen, interpolation to the design end-of-cycle value results in a
target flux difference which more closely follows the measured values in 75%
of the target updates.
This difference between the measured and interpolated values is more pronounced near the end-of-cycle life where the interpolation to zero values continually trend away from the actual measured values.
Therefore, the proposed amendment will allow the use of interpolation to the design end-of-cycle value to more closely reflect actual core conditions and to ensure the reactor is operated within the required i 7% target band.
TABLE 1 CYCLE 5 TARGET DELTA FLUX UPDATES Burnup Measured
. Interpolated Percent Interpolated Percent (MWD /MTU)
Tarcet to Zero
._p_1L 3,p Desien EOL Diff.
'150
-3.1*
N/A N/A N/A N/A 672
-1.2 N/A N/A N/A N/A 1,507
-1.1
-1.1 0
-1.25
.15 2,510
-1.2
-1.0
.2
-1.2 0
i 3,495
-1.7
-1.1
.6
-1.3
- 4 4,180
-2.9
-1.6 1.3
-1.7 1.2 5,157
-2.75
-2.6
.15
-2.85
.1 5,413
-3.9
-2.7 1.2
-2.75 1.15 i
6,422
-3.3
-3.5
.2
-3.7
.4 7,258-
-2.9
-3.0
.1
-3.2
.3 7,840
-2.3
-2.65
.35
-2.85
.55 8,717
-2.6
-2.05
.55
-2.3
.3 9,709
-3.1
-2.2
.9
-2.55
.55 10,724
-3.2
-2.55
.65
-2.95
.25 11,705
-3.15
-2.5
.65
-3.0
.15 13,027
-3.2
-2.05 1.15
-2.8
.4 J
1 14,044
-2.9
-1.8 1.1
-2.8
.1 1
1 15,154
-2.7
.3 2.4
-2.3
.4
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- The design value is used at the beginning of the fuel cycle until a I
measurement is obtained.
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TABLE 2 CYCLE 4 TARGET DELTA FLUX UPDATES Burnup Measured Interpolated Percent Interpolated Percent (MWD /MTU)
Tarret to Zero Diff.
to Desien EOL Diff.
150
-1.9*
N/A N/A N/A N/A 404
-2.6 N/A N/A N/A N/A 1,455
-2.0
-2.4
.4
-2.7
.7 3,425
-2,4
-1.6
.8
-2.3
.1 5,704
-3.8
-1.8 2.0
-2.8 1.0 6,609
-4.1
-3.3
.8
-3.8
.3 7,411
-4.1
-3.5
.6
-4.0
.1 8,400
-4.4
-3.3 1.1
-4.0
.4 9,260
-3.4
-3.4 0
-4.3
.9 10,135
-3.6
-2.4 1.2
-3.5
.1 11,118
-3.3
-2.0 1.3
-3.7
.4 12,197
-3.2
.3 2.9
-3.8
.6
- The design value is used at the beginning of the fuel cycle until a measurement is obtained.
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ATTACHMENT C
9 No Significant Hazards Evaluation Proposed Technical Specification Chanc9 No. 141 Basis for proposed no significant ha ards consideration determination:
The Commission has provided standards for determining whether a
significant hazards consideration exists (10 CFR 50.92(c)).
A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a
significant reduction in a margin of safety.
The proposed changes do not involve a
significant hazards consideration because:
1.
The proposed change incorporates an alternate method of determin3"g the target flux difference by interpolating to the design ad-of-cycle value in place of interpolating to zero.
This will more closely reflect the actual core conditions and aid the operators in maintaining reactor operation within the required i
7%
target band.
This change will not affect the probability of occurrence or the consequences of any accidents previously evaluated in the FSAR since the reactor is still being operated within the design conditions and the method of evaluating reactor operation is being revised to reflect a method demonstrated to be more accurate.
2.
No change to equipment or components is required.
The proposed change will not reduce the safe operation of the plant since interpolation to the design end-of-cycle target flux difference will more closely reflect the actual core conditions to allow a
more accurate indication of plant status.
Comparisen between the methods and results obtained from previous cycles justify the conclusion that interpolation to the design end-of-cycle value is a more accurate indication of plant status and should be used in lieu of interpolation to zero.
Therefore, these changes will not create the possibility of a new or different kind of accident from those described in the FSAR.
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3.
The proposed change is consistent with Bases Section 3/4.2.1
)
" Axial Flux Difference" which requires periodic updating of the target flux difference to reflect core burnup considerations.
The change provides a
more accurate indication of reactor operating status and does not affect the FSAR equipment testing or accident analysis descriptions or results and no FSAR change is required.
The proposed change will not reduce the basis for this or any other technical specification and will not involve a significant reduction in the margin of safety of the plant.
Therefore, based on the above considerations, it is proposed to characterize the change as involving no significant hazards consideration.
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