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Office of New Reactors; Notice of Availability of the Final Interim Staff Guidance DC/COL-ISG-007 on Assessment of Normal and Extreme Winter Precipitation Loads on the Roofs of Seismic Category I Structures

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Nuclear Regulatory Commission (NRC).


Notice of Availability.


The NRC is issuing its Final Interim Staff Guidance (ISG) DC/COL-ISG-007 (ML091490565). This ISG provides clarification of the NRC position on identifying winter precipitation events as site characteristics and site parameters for determining normal and extreme winter precipitation loads on the roofs of Seismic Category I structures.

The NRC staff issues ISGs to facilitate timely implementation of the current staff guidance and to facilitate activities associated with review of applications for early site permits and combined licenses for the Office of New Reactors. The NRC staff will also incorporate DC/COL-ISG-007 into the next revisions of the Regulatory Guide 1.206, “Combined License Applications for Nuclear Power Plants,” and related guidance documents.


The NRC maintains an Agencywide Documents Access and Management System (ADAMS), which provides text and image files of NRC's public documents. These documents may be accessed through the NRC's Public Electronic Reading Room on the Internet at​reading-rm/​adams.html. Persons who do not have access to ADAMS or who encounter problems in accessing the documents located in ADAMS should contact the NRC Public Document Room reference staff at 1-800-397-4209, 301-415-4737, or by e-mail at

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Mr. Brad Harvey, Division of Site and Environmental Reviews, Office of New Reactors, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; telephone 301-415-4118 or e-mail at

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The NRC posts its issued staff guidance on the NRC external Web page (​reading-rm/​doc-collections/​isg/​).

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Dated at Rockville, Maryland, this 23rd day of June 2009.

For the Nuclear Regulatory Commission,

William F. Burton,

Chief, Rulemaking and Guidance Development Branch, Division of New Reactor Licensing, Office of New Reactors.

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[FR Doc. E9-15519 Filed 6-30-09; 8:45 am]