ML20099B962

Cycle 14 Low Power Physics & Power Ascension Test Program

ML20099B962
Person / Time
Site:	Fort Calhoun
Issue date:	07/29/1992
From:	OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20099B960	List: ML20099B956 ML20099B962
References
LIC-92-216R, PROC-920729, NUDOCS 9208030190
Download: ML20099B962 (9)

Text

Attachment LIC-92-216R Page 1-CYCLE 14 LOW POWER PHYSICS AND POWER ASCEN3lON TEST PROGRAM 1.0 LOW POWER PHYSICS TESTS 1.1 Purpose Yhe purpose of the Cycie 14 Low Powe* Physics Tests (LPPT) was to obtain and confirm seled.ed Cycle 14 core physics parameters. The physics parameters measured in the test in:luded:

- All rods out critical boron concentration,

- Isothermal temperature coef ficient of reactivity,

- CEA shutdown Lio regulating group worths using the Rod Group Exchange Technique,

- Verification of the absence of gross power tilts using Group 4 pseudo-ejection symmetry checks.

1.2 Summary of Principal Results Cycle 14 criticality was achieved at 1035 on May 1, 1992. Following criticality, zero power physics testing was initiated to c.easure core physics parameters and validate the core design through comp?rison to predicted values. A summary of the primary results is described telow:

Critical Boron Concentration 1182 ppm (All Rods Out)

Total Regulating and Shutdown 6.00 5.4p Group Worth Isothermal Temperature Coefficient

-0.09 x 10~4 Ap/*F of Reactivity 1.3 Discussion Of Measu_iements and Results 1.3.1. Approach to Criticality l

Following the hot functiorial testir.g in which CEA drop times were

/

measured, the Cycle 14 approach to criticalfry was initiated.

Wide Rarge Channels B and C we e used to determine the subcritical neutron multiplication. The approach to criticality began by withdrawing Rod Groups N, A, B, 1, 2 and 3 to the upper electrical limit and withdrawing Group 4 to Lpproximately 100 inches.

Continuous dilution of the Reactor Coolant System began at 0545 on May 1, 1992, at an averane rate of approximately 2.0 ppm boron 9208030190 920729 PDR ADOCK 05000285 P

PDR

~ N Atthchment iLIC-92-216R-Page 2 m

• 1.0'

-LOW POWER PHYSICS TESTS (Continued) 1.3 Discussion Of Measurements and Results.(Contir.ued) 1.3.1 Approach to Criticality (Continued) e per minute. -Throughout the dilution RCS samples were ar.alyzed 't twenty minute intervals for boron concentration, and extrapolations of 1/M versus dilution time graphs were used to-provide an et,timated time of critica'ity. Initial criticality was. achieved at 1 x 10-4 % power at.035 on May 1, 1992. CEA Regulating Croup 4 was adjusted to 115 inches withdrawn to maintain tne reactor critical during stabilizttion and to prom.ote boron equalization between the pressurizer and the loop. The L

critical boron concentration at the above rod-position was 1177 j.

ppm and was equivalent to an all-rods-out critical boron concentration of 1182 ppm.

1 1.3.2 Zero Power Tests i

"llowing Cycle 14 initial criticality, the reactivity computer 4s installed and checked for correct operation. The following values of [1, and A were set into the reactivity computer:

t Group

[ leer A(sec-1) 1

_0.0002025 0.012751 2

0.0012661 0.031628 g

3 0.0011450 0.11985 4

0.0024650 0.32055 5

0.0009009 1.4021 L

6 0.0002178 3.8662 1-

[1,otai = 0.0061973 1.3.2.1 CEA Coupling Checks Coupling checks were performed for all'CEAs. This was accomplished by inserting' individual rods to achEve -

approximately _a -4( reactivity change. Thi; change corresponded to approximately 20-to _40 inches of insertion. Rods within each group were checked to show similar insertion-that approximated a.~synnetry check.

No abnormalities were observed during the coupling _

checks, and it was concluded that all control rods were prope"ly coupled.

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- Attachmeat-X LLIC-92-216R-Page-3.

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- 1.0! ' LOW POWER PHYSICS TESTS (Continued)

- 1.3-Discussion Of-Measurecents and Results (Continued) 1.3.2 ;Zero Power Tests (Continued) 1.3.2.'2 Isothermal Temperature Coefficient of Reactivity (lTC)

Measurement The ITC was measured by first decreasing and then increasing-the RCS temperature by approximately 20'F and compensating for the reactivity changes with CEA Group 4 motion. The temperature was decreased by

- manually discharging steam through the atmospheric dump valve (HCV-1040).

Initial and final Group 4 positions were recorded. The worth of Group 4 used as compensation was measured from the reactivity computer trace to determine the ITC Table 1 contains the measured and predicted ITC values along with other measured and predicted parameters. The reported value is the average of the two r.:easurements taken from one temperature swing. The Moderator Temperature Coefficient of Reactivity (MTC), which is equal to ti.

ITC minus the Fuel. Temperature Coefficient of Reactivity (FTC), was verified to be less than the 40.5 x 10-8 Ap/ F Technical Specification limit. The most positive'MIC, including uncertainties, was calculated l-to be' +0.03 x 10-4 Ap/ F.

1.3.2.3 Shutdown and Regulating CEA Group Worths L

II The CEA group worths were measured in accordance with References 1 and 2 using the rod group exchange technique. where individual rod groups, called test groups, were measured by swapping them with reference groups whose worths were determined by-the boration-dilution method. The reference group was determined from predictions to be the CEA group with j

the. highest rod worth. Therefore, the worth of the

-test groups is a function of the measured worth of the H

reference group.

For Cycle 14, two viriations of the rod group exchange L'

technique were used. First, one reference group was used for. Cycle 14 instead of two referer.ce groups used 1n previous tests. The use of one reference group saved several hours of rod exchanges and produced-less chemical-waste by decreasing the number of borations of the RCS. The second variatien was the use of the concept called " super groups'.

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. Attachment-

U C-92 216R-Page 4 L.

3

' 1.0 LOW-POWER MlYSICS TESTS (Continued)'

1. 3.

Discussion Of tieasurements and Results (Continued) 1.3.2.3 Shutdown and Regulating CEA Group Worths (Continued) i_y

[

- A super group is a combination of two or more test -

groups into a higher worth rad group. As concludeu in

,y Refere:rces 1 and 2 of Section 3.0, the most accurate test group measurements occur when the test group worth p

is closer to the worth of the reference group. For this test Group B was used as the reference group for Groups A, 1, 2, 3 and 4.

Groups 1 and 2 were combined-into one super group, and Groups 3 and 4 were combined into another super _ group.

All group worths were well within the acceptance and review criteria for the test. The total worth for all

- CEA groups was alsc well within the 10'. acceptance and j

review c.'iteria of the predicted worth. The use of y

super groups for Cycle.14 produced the most accurate measurements of test group worths recorded for a group

' worth measurement testiusing the rod group exchange technique at botn Fort Calhoun Station and other CE e

units.

1.3.2.4 ' Group 4 Eseudo-Ejection Symmetry Check for Gross Power p

Tilt In order to check for ejected rod symmetry and gross power tilts at.2ero power, the full length worth of each of the symetrical Group 4 CEAs ras measured (i.e., eacn Group 4 rod except CEA 4-1 which is the H

center CEA). Table 1.(of this attachment) shows the worth c7 each rcd and the' deviation fro,n the group's

-mean worth. The data in Table 1 indicates that no azimuthal tilt existed in the core at zero power.

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1.4 Conclusions L

lest personnel'have concluded that the Low Power Physics Test program conducted for Cycle 14 yielded results that are as accurate as can bc

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expected _wlthin the limitations of reasonable reactor safety, prudent l

J use' of plant equipment nnd accuracy of available instrzentation. The L

' data collected-during the Cycle 14 Low Power Physics Tests was analyzed l:

by'0maha Public Power District Nuclear Engineering - Reactor Physics.

The results of the Cycle 14 Low Power Physics. Tests show excellent I~

L agreement with the 3-D ROCS code predicted values,-thus providing -

confirmation of the methods used in designing the Cycle 14 core and the associated analyses..

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IAttachmenti

L.IC-92-216R-u

- Page 5 b.;

2.0

' POWER ASCENSION 2,1-iPurpose The purposes of the Cycle 14 power ascension test program was to verify that the measured at-power core parameters were within the limits of

- the Technical Specifications, and to compare selected measured e.

parameterswiththecalculated/predictedvalues. The power ascension test program consisted of:

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-. Measurements of the following parameters at 45%, 66% and 98% power:

n T

In.egrated r ital Peaking Factor' (Fn ),

T

~-~ Planar Radial Peaking Factor (F,y ).

- Azimuthal Power Tilt (T ).

q Determination of reactivity coefficients:

-E Measurement of Isothermal Temperature Coefficient of

_ Reactivity (ITC),

- Measurement of Power Coefficle-t of Reactivity (PC),

. Calculation of Moderator Temperature Coefficient of Reactivity (MTC).

- ' Comparison' of. measured and predicted radial power distributions and calculation of ~ the associated root mean square -deviation -(o).

2.2-Summary of Principal Results Cycle 14. consercial operation began at- 0526 on May 3,1992, when the turbine-generater was placed on-l.ine. Power-ascension began -following this event. J A summary of the pertinent. parameters measured during the

' power Lascenslon testing program are summarized in Table 2 of ~ thir,-

-. report.

a' 2;3 Discussion Of' Measurements and Results 2.3.1 Radial Peaking Factors-T Measurements of Fa and FxyT using incore detector signals and CECOR calculations at 45%, 66% and 98% power indicate that theu integrated radial-peaking factor.-the planar-radial peaking-

. factor, and the excore and incore azimuthal power tilts, Tg and g

Tgt, were within-the limits of the Technical Specificationn I

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1 LIC-92-216Rc Page.61 2.0; POWER ASCENSION 2.3 Discussion Of Measurements and Results (Continued) 2.3.2 MTC,.ITC and. PC Tests were' performed on t'y 21,-1992, to measure the ITC and PC.

The results of this test are sumarized in Continuing Physics Test Report (CPTP) No. 36. The range of the 105 t power MTC, 4

including uncertainties, was -0.76 x 104 Ap/ F to -0.97 x 10 Ap/ F, which is within the Technical Specification limits.

2.3.3 Radial Power Olstribution Comparison i

Comparisons between the measured (CECOR) and calculated (ROCS) radial power distributions at 4%, 66% and 984 power, respectively show that i.he root mean. square values of o are less i

'than the 3% value required by the Technical Specifications.

2.4

' Conclusions Radial.. peaking factors and-azimuthal power tilts were measured at 45%,

66% and 98% power, and found to be within the Technical Specification limits.. MTC-measurements showed. reasonable sgreement with the calculated predictions using ROCS. Measurement of acceptable radial peaking factors:and.a MTC le:3.than the Technical Specification limits demonstrate t_ hat the core'is-operating within the bounds of the safety L

analysis.. Radial pov

.iistributions, measured at 45%, 6% and 98%

power, exhibit reasonc :e agreement with those predicted by ROCS.

These results~ provide confirmation of the core design methodology used and demonstrate compliance with the Technical Specifications.

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- LIC-92-216R

- Page 7'

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3.0" REFERENCES 1.

Letter, D. M. Crutchfield (NRC) to H. Berkow (NRC),

' Review of Topical Report CEN-319, Entitled ' Control

- Rod Group Exchange Technique'" (TACS 60701), March 10, 1986.

2.-

Letter, D. M. Crutchfield (NRC) to R. K. Wells (CEOG),

' Acceptance for Referencing of Licensing Topical Report CEN-319 ' Control Rod Group Exchange Technique'", April

- 16, 1986.

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At taChrt.en t LIC-92-216R Page 8 TABLE 1 CYCLE 14 COMPARISON OF PREDICTED AND MEASURED LOW POWER PH'! SICS PARAMETERS (Hot Zero Power, 2100 psia, 532 F)

Rod Worth by Rod Group Exchange Technique:

Group B Group B Predicted -

Position Position Predicted Measured Peasured (inches (inches Acceptance **

Review'*

Beactivity beactivity Reactivity withdrawn) withdrawn)

Criteria Criteria Group fup)

(up)

(up)

Predicted Measured (up)

(tip) 1+2 1.51 1.53

-0.02 113 111

+0.23 10.23 3+4 1.27 1.25

+0.02 90 78

+0.19 10.19 A

1.59 1.60

-0.01 121 120 10.24

+0.24 B

1.64 1.62*

+0.02 N/A N/A 10.16 10.16 TOTAL 6.01 6.00

+0.01

+0.60

+0.60 Measured via Baration-Dilution Method; Acceptance and Review Criteria are + 10% of predicted versus

+ 15% of predir.ted for.'EA Exchange T :hnique.

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Criteria based upon predicted values.

Isothermal Temperature Coefficient (Ap/ F):

Baron Conc.

Temp.

Mosi. Positive Acceptance Review *

(pr-)

('T)

Prediction Measurement MTC Criteria Crt*eria 1178 522

-0.10x10-4

-0.09x10-4

+0.03x10-4 MTC Tech.

+0.20x10-4 Spec. Limit of

<+0.50x10-*

]

Difference between predicted and treasured ifC.

AR0 Critical Baron Concentration (ppm)1 Acceptance Review Prediction Measurement Predicted-Measured Criteria Criteria 1201 1182

+19

+90 of predicted

+50 of predicted Group 4 Pseudo + eject Symmetry Check for Gross Power Tilt:_

Group-CEA #

CEA Worth (t)

CEA Worth - Gro e.<erale (t) 4-38 21.52 0.44 4-39 20.95

-0.13 4-40 20.94

-0.14 4-31 20.92

-0.16 Averaje = 21.08 Review Criteria is j 1.5* deviation from group average.

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~ Attachment;

LIC-92-216R

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_Page 9=

TABLE 2.

4 PHYSICS PARAMETERS MEASUPED DURING POWER ASCENSION TESTING _ PROGRAM Themal Technical Parameter.

Power (%)

Measured-Value Specification Limit i

g Fa -

45.8 1.64 5 1.9' T

F,y 45.8 1.66 s 2.01 Tqi-45.8 0.0182 5 0.03 Te.

-45.8 0.0019 5 0.03 q

ITl 64.9 1.63 5 1.93 R

T F,y 64.9 1.65 6 2.01 Tat _

64.9 0.0165 s 0.03 Tqi -

64.9-0.0026 6 0.03

' 1.55 x 10-4 Ap/ F.

None PC_

_90.3 ITCJ 90.3

-0.87 x 10-4 Ap/ i None

'MIC.

90.3

-0.74 x 10-4 Ap/ F

-3.0 x-10-4 Ap/ F s MTC g

5 +0.2 x 10-4 Ap/*F

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'_MTC (Extrapolated)=

100

-0.87 x 10-4 Ap/*F

-3.0 x-10-4 Ap/ F $ MTC.

5 +r. 2 x 10-4 Ap/*F -

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.Fa.

98.0 1.61 6 1.79-i 1 98.0.

1.65

$ 1.85 Fxy Tat.

98.0 0.0141 s 0.03 Tqt 98.~u 0.0029 s 0.03 Y..y-