ML042950139

Summary of September 21, 2004 Conference Call with Entergy Re Vermont Yankee Steam Dryer

ML042950139
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	10/28/2004
From:	Richard Ennis NRC/NRR/DLPM/LPD1
To:	Howe A NRC/NRR/DLPM/LPD1
Ennis R, NRR/DLPM, 415-1420
References
Download: ML042950139 (2)

Text

October 28, 2004 MEMORANDUM TO:

Allen G. Howe, Chief, VY Section Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation FROM:

Richard B. Ennis, Senior Project Manager, VY Section /RA/

Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation

SUMMARY

OF SEPTEMBER 21, 2004 CONFERENCE CALL WITH ENTERGY - VERMONT YANKEE STEAM DRYER Attached is a summary of a conference call with Entergy on September 21, 2004, concerning the Vermont Yankee steam dryer analysis supporting the proposed extended power uprate.

Docket No. 50-271

Attachment:

As stated

MEMORANDUM TO:

Allen G. Howe, Chief, VY Section Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation FROM:

Richard B. Ennis, Senior Project Manager, VY Section /RA/

Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation

SUMMARY

OF SEPTEMBER 21, 2004 CONFERENCE CALL WITH ENTERGY - VERMONT YANKEE STEAM DRYER Attached is a summary of a conference call with Entergy on September 21, 2004, concerning the Vermont Yankee steam dryer analysis supporting the proposed extended power uprate.

Docket No. 50-271

Attachment:

As stated DISTRIBUTION:

Non-Public REnnis CWu PDI-2 Reading DSkay TScarbrough BSheron WRuland HGray, RGN-I TMarsh JStang LDoerflein, RGN-I JLyons EImbro CAnderson, RGN-I CHolden KManoly VBucci, OIG AHowe DTerao ADAMS Accession No: ML042950139 OFFICE PDI-VY/PM PDI-VY/SC NAME REnnis AHowe DATE 10/25/04 10/27/04

SUMMARY

OF CONFERENCE CALL WITH ENTERGY VERMONT YANKEE STEAM DRYER ANALYSIS Date: September 21, 2004 NRC Participants Entergy Participants General Electric Participants Rick Ennis Brian Hobbs Dan Pappone Allen Howe Jim DeVincentis Michael Dick Tom Scarborough Ronda Daflucas Lou Quintana Corneilus Holden Craig Nichols John Wu Scott Goodwin David Terao Larry Doerflein Harold Gray On September 21, 2004, the NRC staff held a conference call with Entergy staff at Vermont Yankee, and Entergy's contractor, General Electric, regarding the results of NRC's audit of the steam dryer analysis conducted August 23 through August 26, 2004. The analysis is being used to support Entergy's proposed extended power uprate (EPU) amendment request. Based on the information provided by the Entergy in its submittals, at the public meetings, and during the recent audit, the NRC staff informed Entergy that the analysis submitted to date does not demonstrate that the steam dryer at Vermont Yankee will remain capable of maintaining its structural integrity under EPU conditions. Specifically, the analysis of the Vermont Yankee steam dryer as currently submitted in support of Entergy's EPU request:

1. has not adequately identified and verified the excitation sources for flow-induced vibration mechanisms that resulted in significant degradation of similar steam dryers at other boiling water reactor nuclear power plants operating at EPU conditions;

2. has not provided a complete load definition for the Vermont Yankee steam dryer for EPU conditions in light of several assumptions that have not been adequately justified;

3. has not justified the applied methodology as realistic in light of assumptions to account for uncertainties that resulted in apparent significant overestimation of predicted steam dryer stresses;

4. might be non-conservative based on assumptions for reducing the stress experienced by steam dryer parts and the creation of new potential fatigue failure locations as a result of modifications to the Vermont Yankee steam dryer; and

5. has not validated the extrapolation of pressure peaks from original power levels to EPU conditions for the steam dryer at Vermont Yankee.

The NRC staff also indicated that a purely analytical approach to resolution of the dryer issues was not likely to be successful in demonstrating the ability of the dryers to maintain structural integrity. Consideration should be given to some other method such as instrumentation, or a monitoring strategy, or an incremental power ascension process.