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Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems

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Information about this document as published in the Federal Register.

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Nuclear Regulatory Commission.


Notice of Issuance.


The U.S. Nuclear Regulatory Commission (NRC) has issued Generic Letter (GL) 2008-01 all holders of operating licenses for nuclear power reactors, except those who have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel. The NRC is issuing this GL to address the issue of gas [1] accumulation in the emergency core cooling, decay heat removal (DHR),[2] and containment spray systems (hereinafter referred to as the “subject systems”). Specifically, the NRC is issuing this GL for two purposes:

(1) To request addressees to submit information to demonstrate that the subject systems are in compliance with the current licensing and design bases and applicable regulatory requirements, and that suitable design, operational, and testing control measures are in place for maintaining this compliance, and

(2) To collect the requested information to determine if additional regulatory action is required.

This Federal Register notice is available through the NRC's Agencywide Documents Access and Management System (ADAMS) under Accession Number ML080160231.


The GL was issued on January 11, 2008.


Not applicable.

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Warren Lyon at 301-415-2897 or by e-mail or David Beaulieu at 301-415-3243 or e-mail

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NRC Generic Letter 2008-01 may be examined, and/or copied for a fee, at the NRC's Public Document Room (PDR) at One White Flint North, 11555 Rockville Pike (first floor), Rockville, Maryland. Publicly available records will be accessible electronically from the ADAMS Public Electronic Reading Room on the Internet at the NRC Web site,​NRC/​ADAMS/​index.html. The ADAMS number for the GL is ML070360665.

If you do not have access to ADAMS or if you have problems in accessing the documents in ADAMS, contact the NRC PDR reference staff at 1-800-397-4209 or 301-415-4737 or by e-mail to

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Dated at Rockville, Maryland, this 16th day of January 2008.

For the Nuclear Regulatory Commission.

Martin C. Murphy,

Chief, Generic Communications Branch, Division of Policy and Rulemaking, Office of Nuclear Reactor Regulation.

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1.  “Gas” as used here includes air, nitrogen, hydrogen, water vapor, or any other void that is not filled with liquid water.

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2.  DHR, residual heat removal (RHR), and shutdown cooling are common names for systems used to cool the reactor coolant system (RCS) during some phases of shutdown operation. In this GL, the NRC staff generally uses “DHR.”

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[FR Doc. E8-1302 Filed 1-24-08; 8:45 am]