ML20141A189

Forwards SE Accepting Util 960830,1001,970325 & 0528 Responses to NRC Bulletin 96-003, Potential Plugging of ECCS Strainers by Debris in Bwrs

ML20141A189
Person / Time
Site:	Hatch
Issue date:	06/17/1997
From:	Le N NRC (Affiliation Not Assigned)
To:	Sumner H SOUTHERN NUCLEAR OPERATING CO.
Shared Package
ML20140E302	List: ML20140E299 ML20141A189 ML20141A198
References
IEB-96-003, IEB-96-3, TAC-M96148, TAC-M96149, NUDOCS 9706200158
Download: ML20141A189 (4)

Text

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} p 4 UNITED STATES l

7 j

2 NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30566-4001 j

\*****p! June 17, 1997 l -

j Mr. H. L. Sumner, Jr.

Vice President h

Southern Nuclear Operating Company, Inc.

P. O. Box 1295 j Birmingham, Alabama 35201-1295 i

SUBJECT:

SAFETY EVALUATION RELATED TO NRC BULLETIN 96-03 " POTENTIAL PLUGGING i

0F EMERGENCY CORE COOLING SUCTION STRAINERS BY DEBRIS IN BOILING-i - WATER REACTORS" - EDWIN I. HATCH NUCLEAR PLANT, UNITS 1 AND 2

(TAC NOS. M96148 AND M96149)

Dear Mr. Sumner:

By letters dated August 30 and October 1, 1996, you responded to NRC l Bulletin 96-03 regarding the above subject. In addition, your letter of i March 25, 1997, provided a detailed description of your proposed resolution

approach, and requested NRC staff's approval of your proposed criteria for i sizing the strainers for the emergency core cooling system (ECCS) at Hatch l

Unit 1 only. By letter dated May 15, 1997, the staff requested additional

! information concerning debris generation, strainer configuration, and credit for containment pressure. Your letter dated May 28, 1997, provided responses j

to the staff's request for additional information. The March 25, 1997, letter j also indicated that you will provide a separate submittal for Hatch Unit 2.

1 i The staff, with the assistance of our contractor Science and Engineering l Associates, Inc. (SEA), has completed the review of your submittals, and,

! based on this review, concludes that the proposed criteria for sizing the ECCS i strainers for Hatch Unit I are adequate-to meet the intent of NRC Bulletin  !

96-03. SEA's findings are documented ir, a Technical Evaluation Report (TER) I 1

which is attached to the enclosed staff's safety evaluation (SE). The staff's  !

SE agrees with SEA's findings as documented in the TER. The SE provides our l 4 assessment of your criteria for sizing the new suction strainers for the low- '

pressure coolant injection and the low-pressure core spray systems.

However, I

to date, you have not provided sufficient information to allow the staff to 4

determine the adequacy of the strainer design to handle the calculated debris

! loadings, because the strainer design has not been finalized by your  :

i contractor. Therefore, the information relative to the final dimensions of '

the strainer, the headloss across the new strainer with the calculated debris i loadings (and the basis for the headloss determination), and the resultant net positive suction head margin with the new strainers installed has not been reviewed. The staff requests that this information should be provided in a separate submittal when it becomes available.

! In addition, you indicated in a telephone conference with the staff (R. Elliot i and A. D'Angelo) and J. Branum, Southern Nuclear, on June 2, 1997, that you i were evaluating taking credit for the fact that the strainer is not a solid 2

object in the calculations for determining the hydrodynamic loads on the

strainer. This results in a change in how you calculate the drag force on the

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M*nlet G

M88!L PDR BC R.E CENTER COPY

H. L. Sumner, Jr.  !

strainer. However, you have not yet performed the 10 CFR 50.59 evaluation of this methodology change. If you determine that the hydrodynamic load methodology needs to be revised and that it constitutes an unreviewed safety  ;

question, then you should submit your assessment as svan as possible with due consideration of the time that would be needed for staff review and the short i lead time prior to the fall of 1997 refueling outage. The submittals that i were reviewed did not provide any discussion on how you intend to evaluate the l hydrodynamic loads on the strainer. The staff has, therefore, made no evaluation in this area.

l During the recent Hatch Unit 2 refueling outage, completed in April 1997, the torus was cleaned. This cleaning improved the operability of the existing suction strainers for the emergency core cooling system. Therefore, the staff finds that your proposal to install the strainers at Hatch Unit 2 during the l' refueling outage in the fall of 1998 is acceptable. If you have any questions

, regarding this matter, please contact me at (301) 415-1458.  :

l Sincerely, l 4

Ngoc B. Le, Project Manager

, Project Directorate 11-2 Division of Reactor Projects - I/II i Office of Nuclear Reactor Regulation l

Docket Nos. 50-321 and 50-366

Enclosure:

Safety Evaluation i 4

cc w/ enc 1: See next'page l

l l

t H. L. Sumner, Jr. June 17,1997 l

strainer. However, you have not yet performed the 10 CFR 50.59 evaluation of this methodology change. If you determine that the hydrodynamic load methodology needs to be revised and that it constitutes an unreviewed safety question, then you should submit your assessment as soon as possible with due consideration of the time that would be needed for staff review and the short lead time prior to the fall of 1997 refueling outage. The submittals that were reviewed did not pr, vide any discussion on how you intend to evaluate the hydrodynamic loads on the strainer. The staff has, therefore, made no evaluation in this area.

During the recent Hatch Unit 2 refueling outage, completed in April 1997, the torus was cleaned. This cleaning improved the operability of the existing suction strainers for the emergency core cooling system. Therefore, the staff finds that your proposal to install the strainers at Hatch Unit 2 during the refueling outage in the fall of 1998 is acceptable. If you have any questions regarding this matter, please contact me at'(301) 415-1458.

l Sincerely, (Ori 81nal Signd By)

Ngoc B. Le, Project Manager Project Directorate II-2 ,

Division of Reactor Projects - I/II l Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366

Enclosure:

Safety Evaluation l cc w/ encl: See next page l

( Distribution:  !

Docket File LBerry JJohnson, RI! l PUBLIC NLe PSkinner, RII  !

PD II-2 Rdg.

SVarga CBerlinger OGC /

/ l HBerkow ACRS /

l To rcceive a copy of this document, indicate in the box: "C" = Copy without

}k '

attachment / enclosure "E" = Copy with attachment /enclosurv "N" = No copy l OFFICE PM:PDII-2, IB LA:PDII-t t- BC:SCS('Wlr D:PDIlj-R ,

! NAME NLE:cn 4 A LBERRY M > CBERLINGER HBERK$ F ff i DATE [,/ 0 /97 /,/ D /37 ' / /4, /97 6 /I'/ ' /97 / /97 / /97 i J00UMLN1 NAFE: G:\ HATCH \ STRAINER.SER OFF CIAL RECORD COPY 1d0051

Edwin I. Hatch Nuclear Pirnt '_

Units 1 and 2 cc:

Mr. Ernest L. Blake, Jr. Mr. Thomas P. Mozingo Shaw, Pittman, Potts and Trowbridge Program Manager 2300 N Street, NW. Nuclear Operations ,

Washington, DC 20037 Oglethorpe Power Corporation 2100 East Exchange Place Mr. D. M. Crowe P. O. Box 1349 l Manager, Licensing Tucker, Georgia 30085-1349 l 7

Southern Nuclear Operating  :

l Company, Inc. Charles A. Patrizia, Esquire I P. O. Box 1295- Paul, Hastings, Janofsky & Walker j Birmingham, Alabama 35201-1295 loth Floor l 1299 Pennsylvania Avenue i Resident Inspector Washington, DC 20004-9500  !

l U.S. Nuclear Regulatory Commission i

11030 Hatch Parkway North Chairman ,

l Baxley, Georgia 31513 Appling County Commissioners '

County Courthouse I l

Regional Administrator, Region II Baxley, Georgia 31513 J U.S. Nuclear Regulatory Commission Atlanta Federal Center Mr. W. G. Harriston, III ,

. 61 Forsyth Street, S.W., Suite 23T85 President and Chief Executive 1 l Atlanta, Georgia 30303 Officer Southern Nuclear Operating Mr. Charles H. Badger Company, Inc.

Office of Planning and Budget P. O. Box 1295 l Room 610 Birmingham, Alabama 35201-1295

! 270 Washington Street, SW.

Atlanta, Georgia 30334 Mr. J. D. Woodard l ' Executive Vice President Harold Reheis, Director Southern Nuclear Operating Department of Natural Resources Company, Inc.

l 205 Butler Street, SE., Suite 1252 P. O. Box 1295 l Atlanta, Georgia 30334 Birmingham, Alabama 35201-1295 Steven M. Jackson Mr. P. W. Wells Senior Engineer - Power Supply General Manager, Edwin I. Hatch l Municipal Electric Authority Nuclear Plant

of Georgia Southern Nuclear Operating

! 1470 Riveredge Parkway, NW Company, Inc.

Atlanta, Georgia 30328-4684 11030 Hatch Parkway North Baxley, Georgia 31513

l. - ,,.