ML20058M358

Requests Addl Info Listed in Encl Re Util 900521 & 0720 Responses to NRC Bulletin 90-002, Loss of Thermal Margin Caused by Channel Box Bow. Info Requested within 10 Days of Receipt of Ltr

ML20058M358
Person / Time
Site:	Oyster Creek
Issue date:	08/08/1990
From:	Dromerick A Office of Nuclear Reactor Regulation
To:	Fitzpatrick E GENERAL PUBLIC UTILITIES CORP.
References
IEB-90-002, IEB-90-2, TAC-76342, NUDOCS 9008100067
Download: ML20058M358 (5)

Text

August 8, 1990 Docket'No.

50-219 DISTRIBUTION  % Myt,'fHe NRC& Local PDRs PDI-4'Rdg.

S.Varga(14E4) B.Boger(14A)

Mr. E. E. Fitzpatrtick S.Norris A.Oromerick

i. Vice President and Director E. Jordan (MNBB 3302) OGC Oyster Creek Nuclear Generating Station E.Wenzinger(R-1) ACRS(10)

P. O. Box 388 Forked River, New Jersey 08731

Dear Mr. Fitzpatrick:

L

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING GPU NUCLEAR CORPORATION'S RESPONSE TO NRC BULLETIN 90-02 " LOSS OF THERMAL L MARGIN CAUSED BY CHANNEL BOX BOW" (TAC NO. 76342)

In letters dated May 21, 1990 and July 20, 1990, GPU Nuclear Corporation (GPUN) responded to NRC Bulletin 90-02, " Loss of Thermal Margin Caused By Channel Box Bow." We have reviewed the information and have determined that additional information is required in order fot the staff to complete its review. The specific information requested is presented in the enclosure.

We request that the information be provided within 10 days of receipt of this letter. If you have any questions regarding this request, please contact me. l The reporting and/or recordkeeping requirements contained in this letter affect fewer than 10 respondents; therefore, OMB clearance is not required j under P.L.96-511.  !

Sincerely, signed by J. F. Stolz for Alexander W. Dromorick, Senior Project Manager ,

Project Directorate I-4 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation i '

Enclosure:

As stated cc w/ enclosure: t See next page OFC :LA:PDI-4 :PM: POI-4 / / : PD: POI-4  :  :  :

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NAME StNrrTs~' $ ADromerick:Im $JStoD $  !

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.i DATE :8/7 /90 :8/ 6 /90 :8/%/90  :  :  :

0FFICIAL RECORD COPY l Document Name: TAC 76342

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l Mr.'E. E. Fitzpatrick Oyster Creek Nuclear Oyster Creek Muclear Generating Station Generating Station cc:

Ernest L. Blake, Jr. Resident Inspector Shaw, Pittman, Potts and Trowbridge e/o U.S. NRC 2300 N Street, NW Post Office Box 445 Washington, D.C. c0037 Forked River, New Jersey 08731 Commissioner ,

I. H. Jolles, Executive Vice President New Jersey Department of Energy GPU Senior Corporation 101 Commerce Street 100 Interpace Parkway Newark, New Jersey 07102 Parsipanny, New Jersey 07054 Kent Tosch, Chief Regional Administrator, Region I New Jersey Department of Environmental U.S. Nuclear Regulatory Commission Protection 475 Allendale Road Bureau of Nuclear Engineering King of Prussia, Pennsylvania 19406 CN 415 Trenton, New Jersey 08625 BWR Licensing Manager GPU Nuclear Corporation 1 Upper Pond Road Parsippany, New Jersey 07054 Mayor Lacey Township 818 West Lacey Road Forked River, New 'ersey 08731 Licensing Manager Oyster Creek Nuclear Generri Station Mail Stop: Site Emergency : ;g.

P. O. Box 388 Forked River, New Jersey 08731  ;

o i ENCLOSURE t  :

. r RE0 VEST FOR ADDITIONAL INFORMATION t

Based on our current understanding of your methods for compensating for the impact of channel box bow on thermal margin, the staff believes that your ,

methods are non-conservative and do not assure that the themal margin to the i CPR safety limit is maintained. This assessment is based on the following:

(a) Yoor projected end of cycle (EOC) channel bow is based on Oyster Creek data only. Our examination of your data base in;; sates that it fails to identify a sharp increase in the rate of channel bow which occurs in the 38 to 40 GWD/MTU exposure range for other data. It appears that this '

difference may be due to insufficient data in the advanced exposure range rather than the cited superior performance characteristics of the Oyster Creek channels. Additional bow measurement data in the advanced exposure '

range are needed to substantiate your claim of superior channel bow perfomance due to your procurement control and core management programs.

(b) Youe methods rely partially on GE methodology which has not yet been approved by the staff. If approved, it is likely that its application will be limited to the first bundle lifetime and exposures not exceeding the 38 to 40 GWD/MTV cited absve. While your methods partially account

,, , for non-conservatisms which limit the application of the GE model to lower expc. ores, other concerns are not addressed. For example, core thermal-hydraulic calculations based on assumed bow configurations could over-predict the thermal margin on some channels but underpredict others due to the channel delta-p/ inlet flow distribution relationship.

Unless the staff concerns are alleviated by additional data and infonnation, it is our position that fuel channel boxes in the second bundle lifetime should not be reused in future operating cycles. Our evaluation of your current

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. l operating cycle is continuing. Please provide additional infomation in

. response to the following.

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1. Your response to the expressed staff position and its impact on your next 1 operating cycle, ,

2. A detciled explanation is needed regarding how the coefficients and parameters (BFC, BFP) in your channel bow correlation were derived and exactly how this correlation is applied to channels at different core j

locations having different exposure histories.

3. A detailed discussion is needed regarding exactly how the bow data presented in Figure 2 of your May 21, 1990 submittal have been utilized '

in developing your bow correlation. This discussion should specify .

whether upper bound values, means values, mean plus oneo , etc., are used in the correlation. '

4. In your July 20, 1990 submittal you state that GPUN limits the reuse of channels "to those that have been located only in the central region of the core." Does this mean that the reused channels all remained in the central core region during the entire first bundle lifetime? To clarify this, a description of your fuel shuffling scheme for reloading is needed. ,

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5. Your May'21, 1990 submittal indicates that 150 second lifetime channels reside in the current (Cycle 12) core. We cannot detemine from the ,

infomation provided in your submittals, the total number of bundles (containing these channels) which were analyzed by your methodology.

With reference to Figure 1 of your May 21 submittal, indicate

-specifically which bundles were analyzed, which bundles exhibit the maximum bow, which bundles are limiting bundles, and which of the remaining bundles residing in cells containing the second lifetime channels are fresh fuel bundles. In addition, correlate the channels listed in Table 1 of the May 21 submittal with cigure 1.

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6. Provide limiting plots of predicted bow versus channel exposuit, from the beginning of Cycle 10.(when second lifetime channels were first installed) to the end of the current cycle, to encompass all second lifetime channels currently in the core.  !

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