BVY-91-123, Forwards Response to Generic Ltr 88-20,Suppl 4, Individual Plant Exam of External Events (IPEEE) for Severe Accident Vulnerabilities, Including Methods & Approaches for Performing Exam

Forwards Response to Generic Ltr 88-20,Suppl 4, Individual Plant Exam of External Events (IPEEE) for Severe Accident Vulnerabilities, Including Methods & Approaches for Performing Exam

ML20087B233
Person / Time
Site:	Vermont Yankee
Issue date:	12/19/1991
From:	Pelletier J VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BVY-91-123, NUDOCS 9201130044
Download: ML20087B233 (4)

Text

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- VERMONT YANKEE I NucLGAR POWER CORPORATION r'erry noaa, erattiedero. v105301-7002 d[) )

Vice President. Engineonng s

(802) 257-5271 December 19, 1991 BVY 91-123 United States Nuclear Regulatory Commission ATTN: Document Control Desk

-Washington, DC 20555

References:

a. License No._ DPR 28 (Docket No 50 271)

b. Letter, USNRC to [All Licensees), Generic Letter No. 88-20. Supplement i 4-" Individual Plant Examination of External Events (IPEEE) For Severe i Accident Vulnerabilities," June 28,1991, NVY 91-122 )

c. NUREG 1407, " Procedural and Submittal Guidance for the Individual Plant Examination of Exter,al Events (IPEEE) for Severe Accident Vulnerabilities"

d. Letter, NUMARC to Board of Directors, " Response to Generic Letter 88-20, Supplement 4 to - Allow Coordination With Unresolved Safety issue  ;

(USI) A-46, " Seismic Qualification of Equipment in Operating Plants,"

November 21, 1991

e. Letter, USNRC to VYNPC, Amendment to Technical Speclilcation No.132, Safety Evaiuation Report, [ Toxic Gas Monitoring Tech.Jeal Specifications),

October 24,1991, NVY 91-205

f. Letter, VYNPC to USNRC, " Vermont Yankee Response to Station Blackout Rule, Safety-Evaluation Report" dated July 17,1991, BVY 91-69

g. Letter, VYNPC to USNRC, " Vermont-Yankee Response' to Generic Letter 88 '>0, Supplement 1: Initiation of the Individual Plant Examination for Severe Accident Vulnerabilities - 10 CFR 50.54(f)" dated October 24, 1989, BVY 89100

Subject:

-- Response to Generic Letter _ 88-20 Supplement 4, Individual Plant Examination of External Events (!PEEE) For Severe Accident Vulnerabilities ,

1 Dear Sir.

Reference .b requested all licensees to submit within 180 days from 'Its issuance date, a response which -described the proposed proyams to be used for completing _ the IPEEE including:

1. The identification of methods and approach selected for performing the IPEEE, 2.- The - description- of the method to be used if it has not ';een previously submitted for staff review.

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.gDR The milestones and schedule for performing the IPEEE.

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. VERMONT YANKEE NUCLE AR POWER CORPOR ATION Attachment to BVY 91123 Pago 1 of 2 ITEMS 1 AND 2 Identify the methods and approach selected for performing the IPEEE. Describe the method to be used if it has not been previously submitted for staff review.

RESPONSES 1 AND 2 Vermont Yankee is considering the following external hazard evaluation methodologies for IPEEE resolution:

External Hazard Method of Analysis

1. Seismic SPRA, SMA, or appropriate method

2. Internal Fires FPRA, FIVE, or appropriate method

3. High Winds / Tornadoes Alternate Analysis

4. External Floods Alternate Analysis 5, Transportation Essentially complete via Reference e NOTES A. Specific selection of seismic and internal fire evaluation methodologies are heavily dependent on:

1. The Results Achieved From the Internal IPE Reference c, attachment D notes that IPEEE results and proposed upgrades are only meaningful when considered together with internal IPE results.

Additionally, Reference b page 2 emphasizes the need to complete the IPE so that results can be extended for IPEEE evaluations. With NRC concurrence, VY is' scheduled to complete the Internal IPE on December 31, 1993. This effort is currently on schedule.

2. Resolution of A-46 Methodoloales Generic Letter 88-20, Supplement 4, requests licensees to describe their proposed programs for completing the IPEEEs by December 26, 1991. Also, this generic letter supplement encourages coordination of the seismic IPEEE with Unresolved Safety issue A-46 "so that the objectives of both activities n;ay be accomplished with a slagte walkdown effort." As stated in NRC SECY 91-102, the procedures for_ the seismic walkdown portion of this program are "one of the most important ingredients in implementation of Unresolved Safety Issue (USI) A-46 ..." Vermont Yankee agrees with NRC staff that the walkdowns of each program should be combined into a single walkdown if practical.

Because of the delay in issuance cf the A-46 SSER, Verrr.ont Yankee is not able to submit a firm schedule to complete the seismic portion of the IPEEE until after receipt and review of the SSER. Following this review and the work efforts specified in "A-1" above, Vermont Yankee will develop its program for conducting th seismic IPEEE depending on the content of the SSER and resolution of c en issues.

?

, VERMONT YANKEE NUCLEAR POWER CORPORATION 4

~~~ Attachment to BVY 91-123 Page 2 of 2

3. Resource Requirements for the Analyses Vermont Yankee's severe accident resources consist primarily of Yankee Nuclear Services Division (YNSD) personnel who have an extensive background and analysis capability for severe accidents for all Yankee associated plants. YNSD also has in depth knowledge of VY's design basis. Currently, YNSD's probabilistic resources are working on VY's internal IPE. VY prefers to utilize the same personnel, Yankee and Vermont Yankee, on IPEEE efforts to maximize integration, usefulness of results, and consistency between programs. Due to the large amount of probabilistic analysis work currently ongoing and scheduled for the near term, it le Vermont Yankee's desire to levelize resources over approximately the next three operating cycles.

Based on the above, specific analysis methods will be provided per the milestone schedule provided in item 3.

B. To address high winds and external floods, Vermont Yankee intends to perform the screening analysis described in Figure 1 of Reference b. To address transportation and nearby facility accidents, Vermont Yankee intends to util'ze Figure 1 of Reference b and evaluations developed in Reference e and f.

-ITEM 3 Identify the milestones and schedule for performing the IPEEE and submitting the results to the NRC.

RESPONSE 3 Vermont Yankee intends to pursue IPEEE resoluilon on the following schedule:

ITEM IMPLEMENTATION Continue and complete internal IPE January 1,1990 through effort per Reference g schedule December 31, 1993 Train engineers in SMA and in 1992 (assuming training available)

FIVE techniques (to evaluate option)

Perform and complete High 1993 Wind / External Flood / Transportation IPEEE evaluations Determine best technique to January 31, 1994 (method for

-complete IPEEE for seismic and resolution of seisrnic IPEEE depends internal fire issues and establish upon the contents of the A-46 SSER schedule and satisfactory resolution of current open 1: ems).

Completc seismic and internal fire December 31,1996 (estimate)

IPEEE Complets internal flooding IPE December 31,1996 (estimate)

Submit IPEEE results to NRC March 30,1997 (estimate)

, VERMONT YANKEE NUCLEAR POWER CORPORATION US Nuclear Regulatory Commission December 19, 1991 Page 2 Attached please find Vermont Yankee's response to Reference b, signed under oath and affirmation. Should you have any further questions or comments regarding the enclosed information, please contact this office.

Very truly yours, Vermont Yankee Nuclear Power Corporation ppp 5ames P. Pelletier

- ~ -

Vice President - Engineering Attachment cc: USNRC Region I Administrator USNRC Resident inspector - VYNPS USNRC Project Manager - VYNPS J.C. Butler, Senior Project Manager, NUMARC STATE OF VERMONT W:t: 9AM COUNTY Then personally appeared before me, James P. Pelletier, who, being duly sworn, did state that he is Vice President .

Engineering, of Vermont Yankee Nuclear Power Cor oration, that he is duly authorized to execute and file the fore

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