ML19316A543

Cycle 3 Startup Testing Summary.

ML19316A543
Person / Time
Site:	Oconee
Issue date:	04/30/1978
From:	DUKE POWER CO.
To:
Shared Package
ML19316A541	List: ML19316A540 ML19316A543
References
NUDOCS 8001100758
Download: ML19316A543 (15)

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9 DUKE POWER C0tiPANY OCONEE UUCLEAR STATION UNIT 2, CYCLE 3 STARTUP TESTING Sutt4ARY APRIL, 1978

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DUKE POWER COMPANY OCONEE NUCLEAR STATION UNIT 2, CYCLE 3 STARTUP TESTING

SUMMARY

1. INTRODUCTION The Cycle 3 Startup Test Program for Oconee Unit 2 consisted of p This report provides a sumnary of the zero power test results and includes, where appropriate

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n and predicted values of important core parame,ters. comparisons of measured The zero power physics testing was initiated on August was completed on August 28, 1977.

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, 1977, Testing was conducted with the The core parameters measured included all-rods-ou .

concentration, isothermal temperature and moderator coefficients of worths, ejected rod worth measurements, and diffe measurements.

Section II. The measurements and results are further described in Following satisfactory completion of zero power physics power escalation testing began on August , the testing on January 24, 1978. 28, 1977, and was completed operational problems caused by steam generator leaks, operation at reduced power and outages to repair the leaks. The power escalation tests included core power distribution measurements at approximately 40% FP, 75% FP and 100% FP, power imbalance detector Section III describes the individual tests in the results of these tests. zes

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II. 7ERO POWER PliYSICS TESTI!4G A. Initial Cri ticali_ty_

Cycle 3 initial criticality was achieved on Oconee 2 at 13:10 hours on August 26, 1977 by first withdrawing control rods (Group 7 to 75%

withdrawn and Group 8 to 37.5% withdrawn) and initiating a continuous but regulated feed and bleed deboration of the Reactor Coolant System.

Inverse multiplication plots versus boron concentration and time were maintained, and the feed and bleed was terminated when these plots reached a value of approximately 0.20. Criticality was achieved with equilibrium conditions reached at 13:15 hours with Control Rod Group 7 at 75% withdrawn, and a Reactor Coolant System boron concentra-tion or 1348 ppm.

This measured critical boron concentration of 1348 ppm met the accept-ance criterion of 1317 1100 ppm.

B. All Regulating Rods Out Boron Concentration The all rods out configuration was achieved by boration of Control Rod Group 7 to approximately 97% withdrawn, and then achieving an equili-brium boron condition within the Reactor Coolant System. The Reactor Coolant System boron concentration at these equilibrium conditions was

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sampled and measured to be 1358 ppm. Control Rod Group 7 was then withdrawn to its out limit, and the resulting reactivity insertion corresponded to a 1 ppm increase in boron concentration. The measured all rods out boron concentration with Control Rod Group 8 at 37.5%

withdrawn was therefore 1359 ppm.

This value of 1359 ppm met the acceptance criterion of 1335 ppm +100 ppm.

C. Temperature Coefficients of Reactivity _

The Hot Zero Power temperature coefficients of reactivity were measured at two control rod configurations - all rods out (Group 8 inserted) and Groups 5-7 fully inserted. The test consisted of sequentially changing the RCS tempertaure by -5*F, +10*F, and -5*F and by measuring the associated changes in the core reactivity. The temperature coefficient was obtained by dividing the reactivity changes by the corresponding temperature changes. The moderator co-efficient of reactivity was obtained by subtracting the predicted isothermal Doppler coefficient from the temperature coefficient.

The measured moderator and temperature coefficients of reactivity are aown in Table 1 along with their predicted values. The test satis-factorily met the acceptance criteria requiring the measured and predicted reactivity coefficients to agree within a tolerance of

+0.4 x 10' ( AK/K)/*F and requiring the measured moderator coefficient to be less than +0.5 x 10 ' (AK/K)/*F.

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D. Control Rod Worth Measurements Group integral and differential worths were obtained for Control Rod Groups 5 through 7 with Group 8 at 37.5% withdrawn by debora-tion from an all-rods-out configuration. The measured reactivity worths of the Regulating Control Rod Groups 5 through 7 met the acceptance criteria requiring the predicted worth of the individual groups to be within 115% of the measured value and the predicted total worth of the regulating groups to be within 110% of the mea-sured value. Table 2 illustrates the control rod worth measurement data as well as comparisons to pertinent predicted values.

E. Boron Worth Measurements A measured differential boron worth of 1.034%(AK/K)/100 ppm was obtained, which met the acceptance criterion of 1.003%(AK/K)/100ppmb 110% of measured value.

Ejected Rod Worth Measurement

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In order to measure the worst case ejected control rod worth, Rod 4 in Control Rod Group 6 (predicted to be the most reactive rod) was borated out of the core while Control Rod Group 5 was maintained at 10% withdrawn and Control Rod Group 8 at 37.5% withdrawn. The measured worst case ejected rod worth adjusted for all control rods inserted was 0.477%AK/K. The error adjusted worst case ejected rod worth was calculated to be 0.502%AK/K, which meets the acceptance criteria requiring the error adjusted worth to be less than 1.0%AK/K and to be within 120% (of the measured worth) of the predicted value of 0.49%AK/K.

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III. POWEP. ESCALATION SEQUENCE TESTING A. Core Power Distributian Results Core power distribution measurements were performed a" 40% FP, 75% FP, and 100% FP in order to verify that the measured power distribution is consistent with the predicted distribution.

Corrected instrument readings from the incore instrumentation were taken from the process computer while the plant was operat-ing at these power plateaus and were then compared to calculated power distributions at comparable burn-up, rod pattern, boron concentration, and power levels.

The results of these comparisons are shown on the enclosed eighth core maps of radial and total peaking factors. (Figures 1-6).

Figure 1 shows that the 40% FP radial peaking factors in core locations H-10 and H-12 exceeded the maximum predicted radial peaking factor by +8.7%, which was greater than the ac eptance criterion of +8%. Since the total peaking factors were within acceptance limits (measured <112% of predicted) and the results of other physics testing were acceptable, escalation to 75% FP was carried out. At 75% the radial peaking factors for the two locations remained above the acceptance criterion (+5%). Follow-ing an investigation of the incore detector signal processing and comparisons of detector readings from similar core locations, it was determined that the discrepancy in the two radial peaks could be caused by incorrect depletion and background corrections being made to the measured detector signal. Conservative correction factors were therefore generated for the original processing errors and applied to core locations H-10 and H-12. The resulting power ristribution, shown in Figures 3 and 4, met the acceptance criteria.

Upon completion of the Core Power Distribution Test at 75%, the decision was made to hold the reactor power at 96% FP until satis-factory resolution of the discrepancy in the radial peaks at loca-tions H-10 and H-12 by additional evaluations.

The additional evaluations confirmed the suspected problem with the fixed incore detector string in core location H-12; however, these evaluations showed that the radial and total peaks measured by the fixed incore detector system for core location H-10 were correct.

Therefore, the measured radial peak and total peak in location H-10 exceeded the acceptance criteria at 75% FP by approximately 1%.

Following completion of these analyses, an evaluation of the then current power distribution was performed. Since the power peak in H-10 was bur; 4 down due to core depletion, the measured power distri-bution agreed 'tisfactorily with the core follow calculations, and the 96% power m vel hold was lifted. The unit reached 100% FP on January 18, 1978, and the Core Power Distribution Test at 100% FP was satisfactorily completed on January 24, 1978.

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During the execution of the core power distribution test, the following parameters were checked:

1. SPND background readings and background corrections

2. Reactor power imbalance values

3. Worst case extrapolated minimum DNBR

4. Quadrant power tilt

5. Extrapolated worst case maximum linear heat rate

6. Non-extrapolated worst case maximum linear heat rate

7. Tilt and imbalance values from back-up incore detectors.

Table 3 provides the results of the minimum DNBR and maximum linear heat rate measurements and extrapolations and shows that all values, both extrapolated and measured, met the acceptance criteria.

B. Power Imbalance Detector Correlation Test Results The Power Imbale ce Detector Correlation Test was performed initially at the 40% testing plateau in order to verify that the out-of-core detectors measurement of offset was sufficiently conservative with respect to the incore measured offset to assure that the tolerance assumed in the safety analysis would be met during full power opera-tion. All four out-of-core detectors were verified to satisfy the desired offset correlation.

Following several days operation at full power, the power imbalance detector correlation test at 75% FP was performed to verify that the out-of-core detectors measure core offset within the tolerances assumed in the Safety Analysis (i.e., out-of-core offset = incore of fset +3.5%). The test verified that all four out-of-core detec-tors satisfy the desired offset correlation. A comparison of incore detector imbalance to back-up recorder imbalance showed that for all values of imbalance measured, the maximum difference was well within the +7.5% acceptance criteria for incore to back-up incore calculated offset.

C. Reactivity Coefficient at Power The temperature coefficient of reactivity and the power coefficient of reactivity were measured at the 100% FP testing plateau. The measured temperature coefficient was -1.53 x 10 4(AK/K)/*F which met the acceptance criterion of being less than -0.15 x 10 4(AK/K)/*F for power levels above 95% FP. The B0C temperature coefficient is limited in the negative direction to assure that the limiting E0C value will be less negative than the value assumed in the FSAR steam line break accident. The value measured when the test was per'ormed at 55 EFPD and then extrapolated to B0C conditions met the acceptance criterion. The measured power-Doppler coefficient was -1.04 x 10 4 (AK/K)/%FP. This value is more negative than the upper limit of

-0.55 x 10'4(AK/K)/%FP. These parameters are illustrated in Table 1.

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TABLE 1 SU7ARY OF REACTIVITY COEFFICIENTS PREDICTED VALUE ACCEPTANCE CRITERION CC:!DITIONS MEASURED VALUE HOT ZER0 POWER GP 7 @90%WD Predicted +0.4 x 10-4( AK/ K)/

• F TEMPERATURE GP 8 @37.5%WD +0.186 x 10-4( A K/ K)/

• F +0.115 x 10-4(AK/K)/*F _

COEFFICIENT #1 1358 ppmb

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GP 7 @90%WD Predicted +0.4 x 10 ]( AK/K)/*F HOT ZERO POWER

+0.376 x 10-4(AK/K)/*F +0.305 x 10-4(AK/K)/*F Less than 70.5 x 10- (AK/K)/*F MODERATOR GP 8 @37.5%WD COEFFICIENT #1 1358 ppmb HOT ZERO POWER GP 6&7 00%WD Predicted +0.4 x 10-4(AK/K)/*F TEMPERATURE GP 5 @l2%WD -0.632 x 10-4 ( AK/ K) /

• F -0.810 x 10-4 ( AK/ K)/

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COEFFICIENT #2 GP 8 039.1%WD 1069 ppmb m

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Gp 6&7 00%WD Predicted +0.4x10f(aK/K)/*F HOT ZERO POWER

-0.442 x 10-4( AK/ K)/ *F -0.620 x 10-4(aK/K)/*F Less than 70.5 x 10- (AK/K)/*F MODERATOR GP 5 @l2%WD COEFFICIENT #2 GP 8 039.1%WD 1069 ppmb 55 EFPD 656 ppmb -1.53 x 10-4( AK/ K)/

• F N/A Less than -0.15 x 10-4(AK/K)/'

HOT FULL POWER TEMPERATURE

-1.23 x 10-4( AK/ K)/* F -1.36 x 10-4(AK/K)/*F Greater than -1.43 x 10-4(AK/K)/*F COEFFICIEi4T (extrapolated to 80C) (BOC)

HOT FULL POWER 55 EFPD 656 ppmb -1.04 x 10-4( AK/ K)/%FP N/A Less than -0.55 x 10-4(AKi t)/*F POWER-DOPPLER COEFFICIENT

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TABLE 2

SUMMARY

OF CONTROL R0D WORTH MEASUREMENTS CONTROL R0D PREDICTED MEASURED DEVIATION GROUP WORTH WORTH FROM MEASURED

(%AK/K) (%AK/K) (%)

Group 7 0.86 0.923 -6.83 Group 6 1.02 1.098 -7.10 Group 5 0.95 1.03 -7.77 TOTAL 5-7 2.83 3.05 -7.21 I

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MAXIMUM WORST ACCEPTABLE MINIEUM WORST MAXIMUM 2 CASE WORST WORST ACCEPTABLE CASE ACCEPTABLE EXTRA- CASE CASE WORST MAXIMUM WORST EXTRAP. EXTRA CASE LINEAR CASE WORST EXTRA 1 P0 LATED POLATION MAXIMUM MAXIMUM POLATED EXTRAP.

POWER HEAT MAXIMUM CASE POWER LHR LHR MINIMUM MINIMUM LEVEL RATE LHR Ml11 MUM DNBR DNBR

%FP (KW/FT) (KW/FT) DNBR LEVEL (kJ/FT) (KW/FT) 8.911 85.0 10.30 19.80 3.056 1.30 41.0 4.97 15.5 4.728 105.5 13.16 19.80 2.704 1.30 75.2 9.38 15.5 3.60 105.5 11.38 19.80 2.963 1.30 98.86 10.66 15.5

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• IThe extrapolation power level is the overpower trip setpoint of the next power level plateau in the escalation sequence. >>

2 All cases extrapolated to 105.5%FP. yE 53 c-9 Gm "G

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FIGURE 1 40%FP RADIAL PEAKING FACTORS

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8 9 10 11 12 13 14 15 1.03 1.07 1.44 1.19 1.44 0.95 0.62 0.64 H

0.94 1.07 1.25 1.17 1.32 0.91 0.51 0.70 1.25 1.24 1.32 1.08 1.01 0.78 0.68 K

1.25 1.16 1.28 1.05 0.97 0.83 0.77 0.80 1.32 1.11 0.68 1.08 0.63 L

0.71 1.20 1.00 0.82 1.20 0.70 1.35 1.07 0.87 1.01

" 1.28 1.05 0.94 1.04 Largest Measured Peak = 1.44 0.94 1.15 0.79 Largest Predicted Peak =1.325 N 1.00 1.23 0.82 Deviation From Predicted = +8.68%

0.65 Measured 0

0.71 Predicted Core Conditions for Predicted Core Conditions for Measured Peaking Factors Peaking Factors Group 6 = 90.3 %WD Group 6 = 89.0 %WD Group 7 = 16.1 %WD Group 7 = 14.0 %WD Group 8 = 38.5 %WD Group 8 = 34.0 niD Imbalance = -0.87 %FP Imbalance = -0.53 %FP Core Burnup = 2.0 EFPD Core Burnup = 0.6 EFPD t

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FIGURE 2 40%FP TOTAL PEAKING FACTORS 8 9 10 11 12 13 14

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15 1.22 1.24 1.66 1.40 1.71 1.10 0.69 0.72 H

1.11 1.28 1.52 1.38 i.56 1.03 0.60 0.84 1.45 1.42 1.55 1.27 1.18 0.86 0.79 K

1.51 1.39 1.51 1.21 1.12 0.96 0.93 2.99* 1.64 1.49 0.87 1.22 0.73 0.82 1.41 1.29 0.96 1.44 0.85 1.64 1.38 1.04 1.15

" 1.50 1.24 1.11 1.27 Largest Measured Peak = 1.71 1.04 1.33 0.95 Largest Predicted Peak = 1.559 N 1.19 1.50 1.01 Deviation from Predicted = +9.68%

0.76 Measured 0

0.87 Predicted

Core Conditions for Predicted Core Conditions for Measured Peaking Factors Peaking Factors Group 6 = 90.3 %WD Group 6 = 89.0 %WD

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Group 7 = 16.1 %WD Group 7 =

14.0 %WD Group 8 = 38.5 %WD Group 8 =

34.0 %WD Imbalance = -0.87 %FP Imbalance = -0.53 %FP Core Burnup = 2.0 EFPD Core Burnup = 0.6 EFPD

• Error has been evaluated, and is a result of high substitution for a Level 2 detector.

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FIGURE 3 75%FP RADIAL PEAKIfiG FACTORS

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8 9 10 11 12 13 14 15 1.04 1.04 1.36 1.21 1.36 0.95 0.63 0.65

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N 1.00 1.11 1.25 1.17 1.30 0.93 0.54 0.72 1.26 1.24 1.32 1.09 0.99 0.79 0.70

' K 1.26 1.17 1.27 1.06 0.99 0.84 0.78 0.79 1.31 1.09 0.75 1.08 0.63 L 0.85 1.16 0.70 0.74 1.19 1.01 1.35 1.07 0.87 1.01 N 0.94 1.01 1.25 1.00 Largest Measured Peak = 1.36 0.94 1.13 0.79 Lar9est Predicted Peak = 1.30 N 0.99 1.17 0.81 i Deviation from Predicted = +4.62%

I 0.65 Measured 0

0.71 Predicted

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Core Conditions for Predicted Core Conditions for Measured Peaking Factors Peaking Factors

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Group 6 = 90.3 %WD Group 6 = 89.9 %WD Group 7 = 16.1 %WD Group 7 = 14.1 %WD Group 8 = 25.5 %WD Group 8 = 25.2 %WD Imbalance = -1.18 %FP Imbalance = +0.57 %FP Burnup = 3 EFPD Burnup = 2.79 EFPD 11 .

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FIGURE 4 75%FP TOTAL PEAKIflG FACTORS 8 9 10 11 12 13 14 15 1.21 1.20 1.59 1.37 1.57 1.08 0.68 0.73

" 1.18 1.31 1.49 1.36 .49 1.07 0.67 0.84 1.44 1.44 1.54 1.27 1.15 0.87 0.78 K 1.15 0.96 0.92 1.50 1.36 1.46 1.25 0.92 1.53 1.41 0.89 1.27 0.76 L 1.37 0.83 0.90 1.40 1.34 1.01 1.61 1.38 1.03 1.21 N

1.47 1.25 1.10 1.20 Largest Measured Peak = 1.61 1.03 1.36 0.97 Largest Predicted Peak = 1.501 t1 1.17 1.40 0.96 Deviation from Predicted = +7.26%

0.78 Measured 0

0.84 Predicted Core Conditions for Predicted Core Conditions for Measured Peaking Factors Peaking Factors Group 6 = 90.3 %k'9 Group 6 = 89.9 %WD Group 7 = 16.1 %WD Group 7 = 14.1 %WD Group 8 = 25.5 %WD Group 8 = 25.2 %WD Imbalance = -1.18 %FP Imbalance = +0.57 %FP Burnup = 3 EFPD Burnup = 2.79 EFPD 12

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FIGURE 5 100%FP RADIAL PEAKING FACTORS 8 9 10 11 12 13 14 15 1.02 1.04 1.34 1.15 1.36 0.96 0.79 0.72 H

0.95 1.07 1.24 1.16 1.32 0.91 0.53 0.72 1.18 1.14 1.24 0.96 0.99 0.85 0.75

K 1.25 1.15 1.27 1.04 0.98 0.84 0.78 0.77 1.20 1.06 0.81 1.10 0.69 L

0.71 1.20 1.00 0.84 1.20 0.70 1.25 1.08 0.93 1.16 N

1.27 1.04 0.94 1.03

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largest Measured Peak = 1.36 0.99 1.12 0.80 Largest Predicted Peak = 1.321 N 1.00 1.22 0.81 Deviation from Predicted = +3.0%

0.70 Measured 0

0.72 Predicted Core Conditions for Predicted Core Conditions for Measured Peaking Factors Peaking Factors Group 6 = 90.6 %WD Group 6 =

87.8 %WD Group 7 = 18.75 %WD Group 7 = 11.5 %WD Group 8 = 25.0 %WD Group 8 = 18.3 %WD Imoalance = +0.24 %FP Imbalance = -1.86 %FP Core Burnup = 25.0 EFPD Core Burnup = 55.1 EFPD 13

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• FIGURE 6 100;FP TOTAL PEAKIr4G FACTORS 8 9 10 11 12 13 14 15 1.16 1.18 1.49 1.29 1.58 1.05 0.90 0.79 N

1.09 1.24 1.49 1.37 1.55 1.06 0.66 0.84 1.34 1.28 1.41 1.17 1.10 0.95 0.82 K

1.47 1.35 1.49 1.25 1.15 0.96 0.92 0.99 1.46 1.27 0.92 1.24 0.80 l

0.87 1.44 1.36 1.00 1.40 0.83 1.46 1.29 1.05 1.33

" 1.53 1.26 1.11 1.23 Largest Measured Peak = 1.58 1.05 1.32 0.95

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Largest Predicted Peak = 1.552 il 1.45 0.97 1.19 Deviation from Predicted = +1.80%

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0.79 Measured 0 Predicted 0.86 Core Condit. ions for Predicted Core Conditions for f*easured Peaking Factors Peaking Factors

Group 6 = 90.6 %WD Group 6 r- 67.8 %WD 1 Group 7 = 18.75 %WD Group 7 = 11.5 %WD

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Group 8 = 25.0 %WD Group 8 = 18.3 %WD Imbalance = +0.24 %FP Imbalance = -1.86 %FP Core Burnup = 25.0 EFPD Core Burnup = 55.1 EFPD l 1

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