ML20197A504

Request for Addl Info on Startup Physics Testing Rept of 781015

ML20197A504
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	10/03/1978
From:	Schwencer A Office of Nuclear Reactor Regulation
To:	Reed C COMMONWEALTH EDISON CO.
References
NUDOCS 7810120098
Download: ML20197A504 (3)

Text

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Docket No: 50-295 b% 1 k 1-1 J 11 5 '%.- , .

Coarnonwealth Edison Company ATTN: Mr. Cordell Reed Assistant Vice President Post Office Box 767 Chicago, Illinois 60690 Gentlemen:

We are reviewing your Zion Unit'1 and Cycle 3 Startup Physics Testing Report dated March 15, 1978. Based on discussions with your staff at a May 2,1978 meeting, we understand that you will submit a supplement to that report. We request that your amend-ment address the infonnation identified in the enclosure to this let te r. Please provide your supplement incorporating the enclosed requested information within 45 days of receipt of this letter.

Sincerely, 4

A. Schwencer, Chief Operating Reactors Branch #1 Division of Operating Reactors

Enclosure:

Request for Additional Information ec: See next page

'l #1012 $199

. O O Commonwealth Edison Company October 3,1978 cc

Robert J. Vollen, Esquire 109 North Dearborn Street Chicago, Illinois 60602 Dr. Cecil Lue-Hing Director of Research & Development Metropolitan Sanitary District of Greater Chicago 100 East Erie Street Chicago, Illinois 60611 Zion-Benton Public Library District 2600 Emmans Avenue Zion, Illinois 60099 Mr. John W. Rowe Isham, Lincoln & Beale Counselors at Law One First National Plaza, 42nd Floor Chicago, Illinois 60603 l

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.. O O j RE0UEST FOR ADDITIONAL INFORMATION ZION UNIT NO.1 STARTUP PHYSICS TESTING REPORT 1.

The measured rod worths (Table 4.4.1) were much lower (12%-40%) than predicated. Explain the differences and what has been done to resolve -

them. The boron worth predictions and measurements also differed sub- g stantially. Provide the basis for these' differences and explain what has been done to prevent large differences from recurring in future l cycles.

2. The physics test report demonstrated adequate shutdown margin using data from the conventional boron worths in conjunction with the reactivity computer and an assumed measurement uncertainty of 4%.

Since these measurements have an uncertainty of at least 10%, adequate shutdown margin for EOC can not be demonstrated when the 10% uncertainty is used. State how you have verified shutdown margin for E0C. It should be noted that the rod swap technique should not be used to demonstrate adequate shutdown margin as this technique has not received NRC approval.

3. On page 19 you date that "possible difficulties with the reactivity computer technique are being investigated." Provide the results of this investigation.

4. On page 19 you state that "Possible errors in the predicted reactivity worths are being investigated." Report the results of these investigations.

5. The boron endpoint data and the reactivity computer data come from the same test (page 19). Explain the discrepency between the inferred rod worths obtained using these two data manipulation techniques.

6. Provide the assently-by-assembly flux maps that were taken during startup which were summarized in Table 5.1.2. A.

7. On Page 29 you state "The code generally overpredicted power near the center of the core, and power was mostly underpredicted near the periphery of the core....The core designers are presently working on calculational improvements to achieve a better agreement." Explain the observed /

predicted "in-out" power tilts and the results of investigations on this 4 subject. l

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