ML063390021

Draft RAI Re Proposed Amendment on Contingent Installation of Temporary Spent Fuel Rack

ML063390021
Person / Time
Site:	Monticello
Issue date:	12/04/2006
From:	Tam P NRC/NRR/ADRO/DORL/LPLIII-1
To:	Loeffler R, Salamon G Nuclear Management Co
References
TAC MD0302
Download: ML063390021 (2)

Text

From: Peter Tam To: Loeffler, Rick; Salamon, Gabor Date: 12/04/2006 4:57:53 PM

Subject:

Monticello: Draft RAI re. Proposed Amendment (TAC MD0302)

Rick:

By application dated March 7, 2006, as supplemented by letters dated March 30, 2006, and September 7, 2006, NMC requested to amend the Monticello licensing basis to allow temporary installation of a Programmed and Remote (PaR) Systems Corporation 8x8 (64 cells) high-density spent fuel storage rack in the spent fuel pool (SFP) to maintain full core off-load (FCOL) capability.

NMC provided results of seismic analyses performed in 1977 for the following spent fuel storage rack configurations: 8x10, 8x11, 9x12, and 10x11 cells, using an Iowa plant site response spectrum. NMC utilized the above analyses to qualify the PaR (8x8) spent fuel storage rack at Monticello plant.

The NRC staff reviewed the NMC submittals and has the following comments:

(1) The frequency ranges at which the maximum spectral acceleration amplitude appears differ significantly between Iowa, Monticello response spectra and that from an artificial time history, as tabulated below (based on Figure AA and BB of Enclosure 1 of the 9/7/06 submittal):

Specification Site Frequency Corresponding to Frequency Corresponding to Max.

Max. Horizontal Spectral Acceleration Vertical Spectral Acceleration Iowa 3.6 - 4.5 Hz 3.3 - 6.2 Hz Monticello 1.6 - 2.6 Hz 3.3 - 4.3 Hz Artificial Time History 4.5 - 5.5 Hz 3.3 - 4.3 Hz The Figure AA and BB and the above table indicate that the two response spectra (Iowa and Monticello sites) are significantly different, especially for the rizontal component of the ground motion. More important, contrary to the assertion made by NMC (Section 3.0 (3) of Enclosure 1 to the 9/7/06 letter), the time history spectrum used in the seismic response analysis does not envelop the specific spectrum (Monticello plant site) as required by RG 1.60.

(2) The submittals are lacking structural and seismic analyses for the proposed 8x8 spent fuel storage rack. The seismic analysis results provided by NMC were all for the existing fuel rack configurations at a different plant site, and those rack configurations do not envelop the proposed rack configuration. In addition, only two components (1 horizontal and 1 vertical) of ground motion were considered in the seismic analyses; this is not in compliance with the guidelines of RG1.60.

Please call me to set up either a conference call, or a meeting, to discuss these comments, and how NMC plans to resolve them. The sole purpose of this e-mail is to prepare you and others for the proposed conference call or meeting. This e-mail does not convey a formal NRC staff position, and does not formally request for additional information.

Peter S. Tam, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation e-mail: pst@nrc.gov Tel.: 301-415-1451 Mail Envelope Properties (457499E1.27C : 12 : 35330)

Subject:

Monticello: Draft RAI re. Proposed Amendment (TAC MD0302)

Creation Date 12/04/2006 4:57:53 PM From: Peter Tam Created By: PST@nrc.gov Recipients Action Date & Time nmcco.com Transferred 12/04/2006 4:58:28 PM Gabor.Salamon (Gabor Salamon)

Richard.Loeffler (Rick Loeffler)

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