December 6, 2006
NRC REGULATORY ISSUE SUMMARY 2006-23POST-TORNADO OPERABILITY OF VENTILATING ANDAIR-CONDITIONING SYSTEMS HOUSED IN EMERGENCY DIESELGENERATOR ROOMS
ADDRESSEES
All holders of operating licenses for nuclear power reactors, except those who havepermanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel.
INTENT
The U.S. Nuclear Regulatory Commission (NRC) is issuing this Regulatory Issue Summary(RIS) to notify licensees of its regulatory position regarding loading effects caused by natural phenomena to safety related systems and components housed inside a structure partially exposed to the outside environment, specifically ventilating and air-conditioning (VAC) systems housed in the Emergency Diesel Generator (EDG) roo NRC expects addressees to review this RIS for applicability to their facilities and consider actions as appropriat This RISrequires no action or written response from addressees.
BACKGROUND INFORMATION
During an NRC inspection in May 2005, inspectors questioned the ability of a licensee's VACsystem and other components in an EDG room to operate safely during and after a tornado even Specifically, the NRC staff questioned whether wind pressures and differential pressures caused by a tornado passing directly over the EDG building could adversely affect safety related systems and components inside the EDG building.In response to the NRC questions, the licensee conducted an industrywide survey revealingapproximately 25 plants with a licensing basis similar to their ow In addition, the licensee performed rapid depressurization and re-pressurization analyses (venting) of the EDG room and large deformation inelastic-stress calculations of potentially vulnerable duct segment The licensee's analyses demonstrated and provided assurance that the structural integrity of the VAC system ducts in the EDG room would be maintained during the tornado event, and that afterward the VAC system would be able to perform its intended functio The staff reviewed the analyses and concluded that the integrity of the licensee's VAC system is adequate.ML061720371 RIS 2006-23
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| RIS 2006-02, Good Practices for Licensee Performance During the Emergency Preparedness Component of Force-On-Force Exercises | 23 February 2006 | Backfit | | RIS 2006-02, Good Practices For Licensee Performance During The Emergency Preparedness Component of Force-On-Force Exercises | 23 February 2006 | Backfit | | RIS 2006-04, Draft RAI on Meteorology for Full-Scope AST Application | 11 July 2006 | | | RIS 2006-07, Proposed Changes to the Safety System Unavailability Performance Indicators | 12 June 2006 | Enforcement Discretion
Significance Determination Process
Backfit | | RIS 2006-08, Publicly Available Cover Letters for Security-Related Inspection Reports | 12 June 2006 | Significance Determination Process
Backfit | | RIS 2006-08, Publicly Available Cover Letters For Security-Related Inspection Reports | 12 June 2006 | | | RIS 2006-09, Nrc'S Procedures for Review of Decommissioning Funding Assurance Reports | 21 June 2006 | Backfit | | RIS 2006-09, Nrc'S Procedures For Review of Decommissioning Funding Assurance Reports | 21 June 2006 | | | RIS 2006-10, NRC Regulatory Issue Summary NRC Regulatory Issue Summary 2006-010 - Regulatory Expectations with Appendix R Paragraph III.G.2 Operator Manual Actions | 30 June 2006 | Hot Short
Safe Shutdown
Fire Barrier
Enforcement Discretion
Operator Manual Action
Exemption Request
Fire Protection Program
Backfit | | RIS 2006-10, NRC Regulatory Issue Summary NRC Regulatory Issue Summary 2006-010 - Regulatory Expectations with Appendix R Paragraph Iii.G.2 Operator Manual Actions | 30 June 2006 | Hot Short
Safe Shutdown
Fire Barrier
Enforcement Discretion
Operator Manual Action
Exemption Request
Fire Protection Program | | RIS 2006-12, Us Nuclear Regulatory Commission. NRC Regulatory Issue Summary 2006-12; Endorsement of Nuclear Energy Institute Guidance Enhancements to Emergency Preparedness Programs for Hostile Action. | 19 July 2006 | Safe Shutdown
Backfit | | RIS 2006-12, Endorsing NEI White Paper, Enhancements to Emergency Preparedness Programs for Hostile Action | 19 July 2006 | Backfit | | RIS 2006-13, NRC000046-NRC Regulatory Issue Summary 2006-13, Information on the Changes Made to the Reactor Oversight Process to More Fully Address Safety Culture. | 31 July 2006 | Fitness for Duty
Temporary Modification
Backfit | | RIS 2006-13, 2006/07/31-Intervenor-Exhibit 10-Information On The Changes Made To The Reactor Oversight Process To More Fully Address Safety Culture, Regulatory Issue Summary 2006-13, U.S. NRC | 31 July 2006 | Fitness for Duty
Backfit | | RIS 2006-13, Information on the Changes Made to the Reactor Oversight Process to More Fully Address Safety Culture | 31 July 2006 | Fitness for Duty
Backfit | | RIS 2006-14, NRC Regulatory Issue Summary - Enforcement Requirements for Facility Changes Under 10 CFR 70.72 (c) (2) | 22 September 2006 | Enforcement Discretion
Backfit | | RIS 2006-14, NRC Regulatory Issue Summary - Enforcement Requirements for Facility Changes Under 10 CFR 70.72 (C) (2) | 22 September 2006 | Enforcement Discretion
Backfit | | RIS 2006-15, Withdrawn NRC Regulatory Issue Summary 2006-15 Preparation and Scheduling of Operator Licensing Examinations | 14 August 2006 | Generic Fundamentals Examination
Backfit | | RIS 2006-17, NRC Staff Position on the Requirements of 10 CFR 50.36, Technical Specification, with Respect to Limiting Safety System Settings (LSSS) During Periodic Testing and Calibration of Instrument Channels | 24 August 2006 | Functionality Assessment
Backfit | | RIS 2006-18, Wits200500191/Wits200500192/Wits2005193 - NRC Regulatory Issue Summary 2006-18 Requesting Exemption From the Public Dose Limits for Certain Caregivers of Hospital Patients | 31 August 2006 | Exemption Request | | RIS 2006-18, WITS200500191/WITS200500192/WITS2005193 - NRC Regulatory Issue Summary 2006-18 Requesting Exemption from the Public Dose Limits for Certain Caregivers of Hospital Patients | 31 August 2006 | Enforcement Discretion
Exemption Request | | RIS 2006-19, Availability of Guidance on Radioactive Seed Localization. | 14 September 2006 | Backfit | | RIS 2006-20, Guidance for Receiving Enforcement Discretion When Concentrating Uranium at Community Water Systems | 14 December 2011 | Enforcement Discretion
Pandemic
Backfit | | RIS 2006-20, Enclosure 2 - List of Recently Issued Generic Communication | 14 September 2006 | | | RIS 2006-21, Improving Response Capabilities Through the Use of an Incident Response Electronic Library | 28 September 2006 | Reactor Vessel Water Level
Severe Accident Management Guideline
Backfit | | RIS 2006-22, Lessons Learned from Recent 10 CFR Part 72 Dry Cask Storage Campaign | 15 November 2006 | Safe Shutdown
Exemption Request
Control of Heavy Loads
Fuel cladding
Backfit | | RIS 2006-23, Post-Tornado Operability of Ventilating and Air-Conditioning (VAC) Systems Housed in Emergency Diesel Generator (EDG) Rooms | 6 December 2006 | | | RIS 2006-23, Post-Tornado Operability of Ventilating and Air-Conditioning (Vac) Systems Housed in Emergency Diesel Generator (EDG) Rooms | 6 December 2006 | Earthquake
Backfit | | RIS 2006-25, Requirements for the Distribution and Possession of Tritium Exit Signs and the Requirements in 10 CFR 31.5 Ad 32.51a | 7 December 2006 | | | RIS 2006-25, Requirements For the Distribution and Possession of Tritium Exit Signs and the Requirements in 10 CFR 31.5 Ad 32.51A | 7 December 2006 | | | RIS 2006-26, SECY-06-0248 Enclosure 2 - Regulatory Issue Summary 2006-26, Training and Experience and Grandfather Provisions for Authorized Medical Physicists Under 10 CFR Part 35 | 7 December 2006 | | | RIS 2006-26, Training and Experience and Grandfather Provisions for Authorized Medical Physicists Under 10 CFR 35 | 7 December 2006 | Enforcement Discretion | | RIS 2006-27, Availability of NRC 313A Series of Forms and Guidance for Their Completion | 27 June 2007 | Brachytherapy |
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