ML20210T869

Forwards Response to NRC 870112 Request for Addl Info Re Determination of Rod Worth Using Rod Swap Methodology. Methodology Described in 861204 Submittal Will Be Used for 870501 Reloads of Plants

ML20210T869
Person / Time
Site:	Mcguire, Catawba, McGuire, 05000000
Issue date:	02/11/1987
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20210T874	List: ML20210T869 ML20210T949 ML20210T980 ML20210U020 ML20210U168
References
TAC-62981, TAC-62982, NUDOCS 8702180328
Download: ML20210T869 (5)

Text

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, ., br" Q DUKE POWER COMPANY P.O. Box 33180 ,

CHARLOTTE, N.O. 28242

-H.E B. TUCKER Tztzemown woos.aAB PeopticTion

.(704) oN1 February 11, 1987 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Subj ect: McGuire Nuclear Station Docket Nos. 50-369/370 Catawba Nuclear Station Docket Nos. 50-413/414 Determination of Rod Worth Using Rod Swap Methodology Gentlemen:

By letter dated December 4,1986, Duke submitted for information to NRC a descrip-tion of the method by which bank worths are determined in startup physics testing.

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By letter of January 12, 1987, the Staff responded to the submittal with a request for additional information. Attached are the responses to the Staff's questions.

It is intended that the methodology described in the December 4, 1986 submittal will be used for the next reloads of Duke's Westinghouse plants; the first of which is scheduled for May 1, 1987.

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Very truly yours, t '

pV Hal B. Tucker SAG /54/jgm Attachment h

0702180328 DR 870211 ADOCK 05000369 py f

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• Document Control Desk February-11, 1987 Page 2 xc: Mr. Darl Hood, Project Director ,

Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Conunission Washington, D.C. 20555 Dr. J. Nelson Grace, Regional Administrator U.S. Nuclear Regulatory Conunission - Region II 101 Marietta Street NW - Suite 2900 Atlanta, GA 30323 Mr. W.T. Orders NRC Resident Inspector McGuire Nuclear Station

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• Page 1 s ATTACHMENT e

QUESTION 1: Are all the- rod worth calculations done with the EPRI-NODE-P Code, i

including both rod swap and rod worth for shutdown margin?

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RESPONSE: Shutdown Margin calculations are performed according to the methodology approved in DPC-NF-2010A. Rod worths for both the shutdown margin calculation and the rod swap calculations are done using EPRI-NODE-P.

_ NOTE

See Section 5.4 of DPC-NF-2010A for the procedure for shutdown margin calculations.

QUESTION 2: Section 3, " Measurement Procedure": submit detailed procedures for the measurements. Include the actual boron dilution rate and the flux level. for each of the tests included in the report.

RESPONSE: The most current procedures used in the rod swap measurements are.

enclosed as Attachments 1, 2, and 3.

A summary of the reactivity insertion rates and flux levels for each of the tests in the reference is presented below. Flux levels are values as measured on the reactivity computer picoammeter.

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REACTIVITY INSERTION TEST RANGE POINT OF ADDING UNIT / CYCLE RATE (PCM/HR) (AMPS) NUCLEAR HEAT (AMPS)

MIC2 450 1 E-8 TO 1 E-7 1.4 E-6 MIC3 460 1 E-8 TO 1 E-7 4.25 E-7 1

MIC4 420 1 E-8 TO 1 E-7 5.1 E-7 M2C2 480 1 E-7 TO 1 E-6 1.6 E-6 M2C3 720 ' 1 E-7 TO 1 E-6 1.65 E-6 QUESTION 3: Section 4, " Calculational Procedure" - under 5: How many calculations are performed for each bank and at what positions.

RESPONSE

One o(is calculated for each bank (except for the reference bank) at the predicted critical height. These calculations use the results of cases performed for Sections 4.3 and 4.4 of the reference. Cases are done with the reference bank being inserted in approximately 6-step increments both by itself and in the presence of the bank being predicted.

'Page 2 ATTACHMENT QUESTION 4: Table 3, "cA';s": Are the values given at the predicted heights?

RESPONSE: Alpha (c<) is the ratio of the reference bank worth from the predicted critical height to out of the core with and without bank X in the core. Values for are given at the predicted critical heights. However, the ratio of the reference bank worth with and without bank X in the core is insensitive to variations in the predicted critical heights and will have no significant impact on the inferred worth.

QUESTION 5: Submit a copy of Reference 2.

RESPONSE: Reference 2: Duke Power Company McGuire ~ Nuclear Station, " Control Rod Worth Measurement: Rod Swap Test Procedure," PT/0/A/4150/11A, April, 1984 test procedure is enclosed as Attachment 4.

1 QUESTION 6: Provide data for at least 2 sets of side-by-side comparisons of boron dilution and rod swap data - predicted and measured. The data may be either for your plants or measured data from another plant and predictions by Duke.

RESPONSE

Table with requested data is provided below. All rod worths are given in units of PCM.

UNIT / PREDICTED BOR/ DILUTION  % DIFF R0D SWAP  % DIFF CYCLE BANK WORTH MEAS WORTH ((P-M)/M)*100) INF WORTH ((P-I)/I)*100 MIC2 CD 616 566 8.8 586 5.1 MIC3 CD 488 483 1.0 466 4.7 MIC4 CD 581 580 0.2 556 4.5 M2C2 CD 654 665 -1.7 664 -1.5 M203 CD 591 556 6.3 530 11.5 MEAN 2.9 4.9 STANDARD DEVIATION 4.4 4.6 i

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• Page 3 - l ATTACHMENT 4

QUESTION 7: What Organization does the safety analysis'for the Duke Plants?

When this is not done by Duke, what is done (e.g. tests, comparisons, etc.) to show that the startup test results adequately

' represent the plant features and assumptions used in the safety.

analyses?

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j RESPONSE: -Cycle specific safety reviews and any safety re-analyses required for McGuire and Catawba are performed by Whatinghouse, the current i fuel vendor. Assuming all startup tests meet acceptance criteria, transmittal of the results to Westinghouse is formally accomplished by providing them a copy of the:startup report prepared for the NRC. If any review or acceptance criteria are exceeded, the the action statements in the procedure are followed. Actions. required

' usually include review of the test data and predicted values, ,

" assessment of_ impacts on safety analyses _and technical specification limits, etc. Groups involved in these reviews include the Site Reactor Group, the General Office Nuclear Design Group and, as necessary, Site Compliance, G.O. Licensing, ,

G.O. Safety Analysis, and Westinghouse, The main safety analysis assumption verified by the rod swap procedure is that the plant will maintain adequate shutdown margin 1

per technical specifications. One of the purposes of rod swap

} measurements and comparisons is to verify the accuracy of the total rod worth prediction used as an input to the shutdown margin calculation. An independent Duke Power shutdown margin is

! evaluated for each cycle using methods approved by the NRC in DPC-NF-2010A. The N-1 rod worth used in this prediction is reduced by 10% for conservatism. Acceptance criteria listed in the ,

l procedure indicate that the total inferred rod worth as measured in the rod swap testing must be within 10% of the total predicted j

' worth. If the total measured rod worth is less than the predicted )

worth by more than 10%, a review of the shutdown margin is made to determine if the current rod insertion limits provide adequate i

shutdown margin. If the shutdown margin is adequate, then no i

revision of the limits is necessary. However, if the margin is not i maintained, then Duke will notify Westinghouse, revise the rod l l insertion limits, and submit any necessary changes in the technical i

specifications to the NRC.

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l Reference 1

l McGuire Nuclear Station, Catawba Nuclear Station Rod Swap Methodology Report for i Startup Physics Testing, DPC-NE-1003, Rev.1, December 1986.

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