ML110760666

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Additional Draft RAI Questions Regarding Extended Power Uprate Using the Replacement Stem Dryer
ML110760666
Person / Time
Site: Monticello Xcel Energy icon.png
Issue date: 03/16/2011
From: Tam P
Plant Licensing Branch III
To: Gunderson L, Fields J
Northern States Power Co
Tam P
References
TAC MD9990
Download: ML110760666 (2)


Text

Accession No. ML110760666 From: Tam, Peter Sent: Wednesday, March 16, 2011 12:11 PM To: Gunderson, Lynne; John.Fields@xenuclear.com Cc: Basavaraju, Chakrapani; Khanna, Meena

Subject:

Monticello - Additional Draft RAI Questions for Extended Power Uprate Using the Replacement Steam Dryer (TAC MD9990)

Lynne, John:

Based on a review of the NSPM submittals as well as the information the staff heard during the March 4, 2011, conference call with you and others, the NRC staff has identified the following questions regarding the replacement steam dryer (RSD), for which additional information is needed before the NRC staff can complete its review. I propose that we discuss these questions in our 3/17/11 conference call.

MNGP-EMCB-SD-RAI-39.

The licensee is requested to provide a summary table of the operating and geometric parameters of the European and/or other BWRs with the Nordic steam dryer in comparison to that of the proposed replacement steam dryer Monticello. The operating parameters should include length of operation, power level, steam velocities, steam quality, steam temperature, moisture content, and steam pressure. The geometric parameters should include steam dryer diameter; vessel shape, diameter and height; main steam line (MSL) diameter and entry points to the reactor pressure vessel; relative locations of safety valves along the MSLs; valve standpipe diameters and lengths, and the presence of any dead-end pipe segments.

MNGP-EMCB-SD-RAI-40.

The licensee is requested to provide a summary of the operating experience describing whether any Nordic steam dryer has experienced cracking or other damage during operation. In the case that there was Nordic dryer cracking or damage, the licensee is requested to explain what caused the damage. If the damage includes fatigue cracking, the licensee is requested to provide a root cause analysis report for such cracking. The licensee is further requested to demonstrate that the stress analysis approach proposed for the Monticello replacement steam dryer will have the capability to predict such cracking and the cracking location(s) to provide assurance regarding the validation of the proposed approach.

MNGP-EMCB-SD-RAI-41.

The licensee is requested to submit the instrumentation plan of the replacement steam dryer at Monticello for staff review. The staff requests that the licensee include, in the plan, the types of sensors (accelerometers, pressure sensors, and strain gages) to be used, identifying/justifying their locations, and addressing how the measured results would be used.

This e-mail does not formally convey an NRC staff position, and does not formally request for additional information. How the above draft RAI questions will be dispositioned will be discussed and agreed to during the 3/17/11 conference call.

Peter S. Tam Senior Project Manager (for D. C. Cook and Monticello)

Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Tel. 301-415-1451