ML052790448

Fax from D. Pelton of USNRC to C. Anderson of USNRC, Regarding Draft Press Release Regarding VY Dryer Cracking

ML052790448
Person / Time
Site:	Vermont Yankee
Issue date:	04/16/2004
From:	David Pelton Division Reactor Projects I
To:	Anderson C NRC Region 1
References
FOIA/PA-2004-0369
Download: ML052790448 (2)

Text

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-' I U.S. Nuclear Regulatory Commission Resident Inspector Office at Vermont Yankee Ii I Facsimile To: Cliff Anderson, Chief, Projects Branch 5 i

I o Don Florek, Senior Project Engineer I

0 Becky Junod, Branch Secretary I

I 0

Date:

y464' Total Pages:

Facsimile From: David Pelton, Senior Resident Inspector o Beth Sienel, Resident Inspector a Amanda Rancourt, Office Assistant 0

Notes:

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? to/K~ ay@X Office Phone: (802) 257-4319 Office Fax: (802) 257-7791

PR-16-2004 09:07 USNRC RESIDEN) LU-f-ILI: Vy r Brattleboro, VT - Vermont Yankee outage workers have identified minor hairline cracking in the plant's steam dryer - a component used to remove moisture from steam produced in the plant's reactor. The condition, which has no impact on nuclear safety, was discovered in a comprehensive inspection conducted by the General Electric Company, Vermont Yankee's original designcr, after similar conditions were found at other U.S. boiling water reactors.

Based on engineering evaluations, two weld sections - each about tree inches long -

were ground out and rewelded. As a conservative measure, those two locations, and two similar locations - all in low stress areas - were stiffened with plate steel. The inspection also identified two other hairline cracks, one 14 inches long and one three inches long, which were evaluated and found to be inconsequential and will be monitored in place as part of the routine high resolution visual inspections that are done during refueling outages.

The steam dryer was subject to comprehensive visual inspection during this outage because other US plants had identified steam dryer cracking associated with an increase in plant power output as proposed by Vermont Yankee.

Entergy Vermont Yankee Site Vice President Jay Thayer said the cracks were not in the areas of the steam dryer that had presented problems at other plants. "These were in non-stressed areas of the dryer that are not exposed to heavy steam flows. In fact, the components of the dryer that carry most of the load - the ones that presented problems at other plants - are in good shpe. However, in accordance with our uprate engineering analysis, those will be replaced with heavier steel plates."

Besides the repairs and strengthening done to these welds, the preplanned outage schedule includes reinforcing the dryer in several other areas based on the experience of similar boiling water reactors that have increased their power output.

The repairs are designed to ensure the continued reliability of the steam dryer and the continued reliability of Vermont Yankee with increased power output TOTAL P.02