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Final Interim Staff Guidance: Review of Evaluation To Address Gas Accumulation Issues in Safety Related Systems

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Nuclear Regulatory Commission.


Notice of availability.


The U.S. Nuclear Regulatory Commission (NRC) staff is issuing its Final Interim Staff Guidance (ISG) DC/COL-ISG-019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML111110572). The purpose of this ISG is to clarify the NRC staff guidance to address issues of gas accumulation in safety related systems. This ISG revises and updates the guidance provided to the staff in Standard Review Plan (SRP) Section 5.4.7, “Residual Heat Removal System,” Section 6.3, “Emergency Core Cooling System,” and Section 6.5.2, “Containment Spray System” of NUREG-0800, “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants,” March 2007. The NRC staff issues DC/COL-ISGs to facilitate timely implementation of current staff Start Printed Page 58847guidance and to facilitate activities associated with review of applications for design certifications and combined licenses by the Office of New Reactors. The NRC staff intends to incorporate the final approved DC/COL-ISG-019 into the next revision of the SRP and related guidance documents.

Disposition: On November 12, 2009 (74 FR 58323), the NRC staff issued proposed DC/COL-ISG-019 on “Review of Evaluation to Address Gas Accumulation Issues in Safety Related Systems,” ADAMS Accession No. ML092360375. The staff received comments (ADAMS Accession No. ML093500086) on the proposed guidance on December 14, 2009. These comments were further discussed in a public meeting held at the NRC on January 20, 2010, and in a conference call on July 9, 2010. This final issuance incorporates changes from the majority of the comments. A document comparing the version of the ISG that went out for public comment and the final version of the ISG can be found under ADAMS Accession No. ML111170302.


Publicly available documents created or received at the NRC are available online in the NRC Library at​reading-rm/​adams.html. From this page, the public can gain entry into ADAMS, which provides text and image files of the NRC's public documents. If you do not have access to ADAMS or if there are problems in accessing the documents located in ADAMS, contact the NRC's Public Document Room reference staff at 1-800-397-4209, 301-415-4737, or by e-mail to

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Mr. Joseph E. Donoghue, Chief, Reactor Systems, Nuclear Performance and Code Review Branch, Division of Safety Systems & Risk Assessment, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; telephone at 301-415-1193 or e-mail at

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The agency posts its issued staff guidance in the agency external web page (​reading-rm/​doc-collections/​isg/​).

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Dated at Rockville, Maryland, this 9th day of September, 2011.

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. 2011-24344 Filed 9-21-11; 8:45 am]