ML072900255

Response to Request for Additional Information Concerning Proposal to Revise Commitments to USNRC Regulatory Guide 1.82, Rev .0 Sumps for Emergency Core Cooling and Containment Spray Systems and Revising Technical

ML072900255
Person / Time
Site:	Catawba
Issue date:	10/12/2007
From:	Morris J Duke Energy Carolinas, Duke Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RG-1.082, TAC MD5163, TAC MD5164
Download: ML072900255 (6)

Text

kDuke JAMES R MORRIS

Energy, Vice President Catawba Nuclear Station 4800 Concord Road / CN01 VP York, SC 29745-9635 803 831 4251 803 831 3221 tax October 12, 2007 U.

S. Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555-0001

Subject:

Duke Power Company LLC d/b/a Duke Energy N.,

Carolinas, LLC Catawba Nuclear Station, UniLs 1 and 2 Docket Nos.

50-413, 50-414 Response to a Request for Additional Information (RAI) concerning the Catawba Nuclear Station Units 1 and 2 Proposal to Revise Commitments to USNRC Regulatory Guide 1.82, Rev.0 "Sumps For Emergency Core Cooling and Containment Spray Systems" and Revising Technical Specification Surveillance Requirement (SR) 3.5.2.8 and Associated Bases (TAC Nos.

MD5163 and MD5164)

Please find the Duke Energy Carolinas (Duke) response to a Request for Additional Information (RAI) concerning the license amendment request (LAR) to Revise Commitments to USNRC Regulatory Guide 1.82, Rev.0, "Sumps For Emergency Core Cooling and Containment Spray Systems" and Revising Technical Specification Surveillance Requirement (SR) 3.5.2.8 and Associated Bases. This LAR was originally submitted by a Duke letter to the NRC dated March 29, 2007." The RAI response on September 7, 2007 left one question unanswered: Question #3 on from the Safety Issues Resolution Branch. This delay was due to the need to obtain vendor calculations to confirm the response. Attachment 1 of this document contains the response to RAI Question #3.

There are no regulatory commitments in this letter.

www. duke-energy. corn

U.S. Nuclear Regulatory Commission October 12, 2007 Page 2 If any questions arise or additional information is

needed, please contact Tony Jackson at (803) 831-3742.

Very truly yours, orris Attachment

U.S. Nuclear Regulatory Commission October 12, 2007 Page 3 James R. Morris affirms that he is the person who subscribed his name to the foregoing statement, and that all the matters and facts set forth herein are true and correct to the best of his knowledge.

JameS.

MPoreid**io Vice President, Catawba Nuclear Station Subscribed and sworn to me:

Notary c

ublic My commission expires:

i/ /Z-a7 Date Date "W"

U.S. Nuclear Regulatory Commission October 12, 2007 Page 4 xc: w/attachments W. D.

Travers, Region II Administrator U.S. Nuclear Regulatory Commission Sam Nunn Atlanta Federal Center, 23 T85 61 Forsyth St.,

SW

Atlanta, GA 30303-8931 J.

F.

Stang, Jr., Senior Project Manager (CNS & MNS)

U.

S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop 8 G9A Rockville, MD 20852-2738 A.

T. Sabisch Senior Resident Inspector U.

S.

Nuclear Regulatory Commission Catawba Nuclear Station H.

J.

Porter, Assistant Director Division of Radioactive Waste Management Bureau of Land and Waste Management Department of Health and Environmental Control 2600 Bull Street

Columbia, SC 29201

U.S. Nuclear Regulatory Commission October 12, 2007 Page 5 bxc (with attachments):

R.

D. Hart R.

L. Gill A.

P. Jackson K.

E. Nicholson NCMPA-1 NCEMC PMPA SREC Catawba Document Control File: 801.01 -

CN04DM Catawba RGC Date File ELL-EC050

ATTACHMENT 1

RESPONSE TO THE REQUEST FOR ADDITIONAL INFORMATION QUESTION #3 FROM THE SAFETY ISSUES RESOLUTION BRANCH CATAWBA NUCLEAR STATION,. UNITS 1 AND 2

3.

As stated in attachment 3, section 2.2 "New ECCS Stump Strainer Assembly Design" of the submittal, the new strainer offers approximately 2000 square feet of surface area versus the original 135 square feet total for the original sump screens. Due to the magnitude of the increase of metallic heat sink mass, the post-LOCA containment temperature and pressure behavior may be subject to change.

Please provide a summarized analysis of the effects on the post-LOCA peak cladding temperature (PCT) due to the change in containment pressure and temperature behavior.

Response

An evaluation was performed by Westinghouse to determine the impact of the increased containment metal mass and surface, area on the Best Estimate Large Break LOCA (BELOCA) analysis for Catawba.

The LOTIC2 computer code was used, consistent with the containment backpressure methodology for the Catawba.

BELOCA analysis of record.

During the LOCA reflood phase, where containment pressure can influence the Peak Clad Temperature (PCT),

a maximum reduction in containment pressure of 0.01 psig was observed when the additional sump strainer material was taken into account.

Furthermore, the current LOTIC2 analysis of record includes some margin in Mass and Energy (M&E) release from the primary vessel during blowdown.

From the LOTIC2 results and the M&E margin, Westinghouse has concluded that the additional containment metal mass has a negligible impact on the containment pressure/temperature and therefore a negligible impact on the resulting PCT. Duke agrees with this conclusion.