ML20114E511

Revises Equation & Definitions Provided in 790524 Submittal Re Rod Worth Measurements Used in Startup Physics Testing. Conclusions of Remain Unchanged:Predictions Adequate

ML20114E511
Person / Time
Site:	Point Beach
Issue date:	06/20/1979
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton, Schwencer A Office of Nuclear Reactor Regulation
References
NUDOCS 7907030372
Download: ML20114E511 (2)

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WISCONSIN Electnc eoww coww 231 W. MICHIGAN, P.O. BOX 2046, MILWAUKEE, WI 53201 June 20,1979 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C. 20555

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] ,Ihhh, j riir rt. CDPii V Attention: Mr. A. Schwencer, Chief Operating Reactors Branch #1 Gentlemen:

POINT BEACH UNIT 2 CYCLE 6 STARTUP PHYSICS TESTING - R0D WORTH MEASUREMENTS REPORT Attachment A to our letter of May 24, 1979, reported the results of the Unit 2 beginning-of-Cycle 6 rod worth measurements which employed the

" rod swap" methodology. As a result of discussions with a member of your staff it was discovered that the formulation of Section 3.2 of the Rod Worth Measurements Report was not consistent with the equations submitted to the NRC by Westinghouse in November 1978. The results presented in Table 2 of the report should accordingly be changed to reflect the 1978 formulation.

Specifically, the equation and definitions presented in Section 3.2 should read as follows:

Wf = - a pi - (a )(ap2) x + WE where:

Wf=TheinferredworthofBankX,pcm

= The measured worth of the reference bank, Control A from fully withdrawn to fully inserted with no other bank in the core, ox = A design correction factor taking into account the fact that the presence of another control rod bank is affecting the worth of the partially inserted reference bank.

Ao2 = The measured worth of the reference bank from its elevation, at which the reactor is just critical with Bank X in the core, to the reference bank fully withdrawn condition.

This worth of the reference bank is measured with no other bank in the core. Therefore, the ax correction factor is e-A 7907030377- ,,

g/4 /

$tb

Mr.'HaroldR.Denton-Pa(lwo June 20,(379 api = The measured worth of the reference bank from the fully

' inserted condition to the elevation at which the reactor was just critical prior to the worth measurement of Bank X. In the test opi is ze'ro.

Wf=TheworthofBankXfromtheinitialposition(before the start of the exchange) to 228 steps. This worth is measured by the normal endpoint worth method.

Using this formulation, Table 2 should read as follows:

TABLE 2

, COMPARISON OF INFERRED / MEASURED BANK WORTHS WITH DESIGN PREDICTIONS UNIT 2 CYCLE 6 W(pcm) Wj(pcm) W[(pcm)

Bank X g ,,

CC 658 0.977 40 966 1005 -3.9 SB 815 0.997 20 776 807 -3.8 SA 459 1.026 23 1121, 1125 -0.4 CD 902 0.994 34 706 742 -4.8 CB 959 1.041 39 610 606 +0.7 CA - - -

1569* 1560 +0.6 TOTAL 5748 5845 -1.7

• (='1569 P

• • (Wj-W)100 W[

As you will note, the conclusions of the May 24, 1979 letter are unchanged. The review and acceptance criteria for the measurements were met and the adequacy of the nuclear design rod worth predictions was demon-strated.

i Very truly y r, dM y C. W. Fay, Director Nuclear Power Department 2

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