ML20136B636

Completes Response to RAI Re Summary of Methodology That Util Plan to Use to Reanalyze Containment Pressure Response Following Loca.Rev to Methods Summary Rept Encl.Encl Withheld Per 10CFR2.790

ML20136B636
Person / Time
Site:	Maine Yankee
Issue date:	03/03/1997
From:	Sellman M Maine Yankee
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20057G423	List: ML20136B636
References
MBS-97-06, MBS-97-6, MN-97-21, NUDOCS 9703110067
Download: ML20136B636 (3)

Text

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MaineYankee RELIABLE ELECTRICITY SINCE 1972 329 BATH ROAD + BRUNSWICK. MAINE 04011 + (207) 7984100

March 3,1997 l MN-97-21 MBS-97-06 1

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. UNITED STATES NUCLEAR REGULATORY COMMISSION t Attention: Document Control Desk Washington, DC 20555 l

References:

(a) License No.' DPR 36 (Docket No. 50-309) l (b) MY Letter to USNRC dated April 12,1996 (MN-96-048) - Integrated Containment Analysis - Methods Summary and Identification of Differences from SRP 4

(c) USNRC Letter to Maine Yankee dated May 31, 1996 - Maine Yankee Containment Reanalysis (TAC NO. M94835) 1 (d) MY Letter to USNRC dated July 23,1996 (MN-96-102) - Response to RAI L Integrated Containment Analysis

! (e) MY Letter to USNRC dated October 3,1996 (MN-96-144) - Second Response

!- to RAI - Integrated Containment Reanalysis Methodology (f) MY Letter to USNRC dated December 4,1996 (MN-96-182) - RAI - Integrated l

l Containment Reanalysis Methodology i

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(g) MY Letter to USNRC dated December 29,1995 (MN-95-141)- Containment i Leakage at Peak Accident Pressure and Use of 2700 MW Reactor Protective )

System Setpoints for 2440MW Operation l

Subject:

Third Response to RAI - Integrated Containment Reanalysis Methodology Gentlemen:

We submitted a summary of the methodology we plan to use to reanalyze the containment pressure response following a LOCA in Reference (b). Your staffissued a request for additional information (RAI) on our proposed methodology in Reference (c). The purpose of this letter is to complete our responses to your RAI and submit a revision to our Methods Summary Report, which was submitted to you in Reference (b).

We responded to several of your RAI questions in previous letters. We responded to seven of the thirteen questions posed in your RAI in Reference (d). We responded to four additional questions posed in your RAI in Reference (e) and provided a schedule for responding to the remaining two questions. In Reference (f) we revised that schedule.

Our responses to the two remaining questions, as well as the responses to the other eleven questions, are provided in the enclosure as Appendix A of the revised Methods Summary Report. As a result ofour planned assessment ofRELAPS/ MOD 3, it was determined that the code under-predicted the heat transfer between the secondary and primary sides of the steam generators. Since this is non-conservative for containment maximum pressure evaluations,' a code modification was implemented to increase the droplet-to-vapor interfacial heat transfer in the post-CHF regime. This change resulted in the secondary-to-primary heat transfer being well predicted for all tests evaluated in this assessment. One of the previously answered questions in your RAI was affected by this code modification. Hence, our response to that question has been revised to be consistent with the code version that we now intend to use for the containment reanalysis.

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MaineYankee UNITED STATES NUCLEAR REGULATORY COMMISSION MN-97-21 Attention: Document Control Desk Page Two In addition to containing our responses to your RAI and additional detail, the revised Methods Summary Report provides the results of sample calculations performed for Maine Yankee using the proposed methodology. These calculations used inputs similar to analyses that form the basis for information provided to you in Reference (g) regarding the containment leakage at peak accident pressure.

Since the revision to the RELAP5/ MOD 3 code was implemented very recently, documentation and Quality Assurance review for several of the calculations, which are the bases of these responses, could not be completed in time for this response. This documentation and review will be completed by March 30,1997. We currently expect to submit the analysis results and associated proposed technical specification change by June 16,1997.

The enclosed information is considered proprietary by Yankee Atomic Electric Company. In accordance with 10CFR2.790(b)(1), an affidavit attesting to the proprietary nature of the enclosed information is attached as Enclosure A.

We trust that the information in this letter is satisfactory. Please contact me if you have any questions.

Very truly yours, Michael B. Sellman President c: Mr. H. J. Miller Mr. D. H. Dorman Mr. J. T. Yerokun Mr. Clough Toppan Mr. Patrick J. Dostie Mr. Uldis Vanags Donald Zillman, Esq.

Lawrence J. Chandler, Esq.,

Assistant General Counsel for Hearings and Enforcement Enclosure A: Affidavit Enclosure B: Proprietary Information STATE OF MAINE Then personally appeared before me, M. B. Sellnman, who being duly sworn did state that he is President of Maine Yankee Atomic Power Company, that he is duly authorized to execute and file the foregoing response in the name and on behalf of Maine Yankee Atomic Power Company, and that the statements therein are true to the best of his knowledge and clief.

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Notary Public/

My Commission expirec - - - - - - - - - - - - - - - - -

BAfGARA J. PADAVANA l

NearyPenn,amhof thhs l

.W.0]JHOLD ENCLOSURES  : ____ #f f f f 8"y l FROM PUBLIC DISCLOSURE

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,- AFFIDAVIT PURSUANT TO 10CFR2.790 t

l Yankee Atomic Electric Company l

Nuclear Services Division Commonwealth of Massachusetts

Worcester County s

I, S. P. Schultz, depose and say that I am the Vice President of Yankee Atomic Electric Company, duly

. authortzed to make this affidavit, and have reviewed or caused to have reviewed the information which is identified as proprietary. I am submitting this affidavit in accordance with the provisions of 10CFR2.790 of the Commission's regulations for withholding this information.

The information for which proprietary treatment is sought is contained in the enclosures to our letter, Maine Yankee Atomic Power Company to U. S. Nuclear Regulatory Commission, dated January 30,1997.

Pursuant to the provisions of Paragraph r ' Section 2.790 of the Commission's regulations, the following is furnished for consideration bj . amission in determining whether the information sought to be withheld from public disclosure, included .a me referenced document, should be withheld.

1. The material contained in this transmittal was obtained at considerable expense to Yankee Atomic Electric Company and Mainc Yankee Atomic Power Company and the release of which would seriously affect our competitive position.

2. The material contained in this transmittal is of the type customarily held in confidence and not customarily disclosed to the public.

3. This information is being transmitted to the Commission in confidence under the provisions of 10CFR2.790 with the understanding that it is to be *.eceived in confidere by the Commission. l l

4. This information is for Commission internal use only and should not be released to persons or organizations outside the Directorate of Regulation ard the ACRS without prior approval of Yankee Atomic Electric Company. Should it become necessary to release this information to such persons as part of the review procedure, please contact Yankee Atomic Electric Company. l Further deponent sayeth not.

Swom ta before me this 3rd day of February,1997 M '

S. P. Schultz Vice President 1

YdM//u/x [i,mab '

Notary Public ,.

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