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Category:NRC Information Notice
MONTHYEARML16028A3082016-04-27027 April 2016 NRC Information Notice; IN 2016-05: Operating Experience Regarding Complications From a Loss of Instrumentation Air Information Notice 2011-17, Calculation Methodologies for Operability Determinations of Gas Voids in Nuclear Power Plant Piping2011-07-26026 July 2011 Calculation Methodologies for Operability Determinations of Gas Voids in Nuclear Power Plant Piping Information Notice 2007-29, Temporary Scaffolding Affects Operability of Safety-Related Equipment2007-09-17017 September 2007 Temporary Scaffolding Affects Operability of Safety-Related Equipment Information Notice 2007-06, Potential Common Cause Vulnerabilities in Essential Service Water Systems2007-02-0909 February 2007 Potential Common Cause Vulnerabilities in Essential Service Water Systems Information Notice 2006-31, Inadequate Fault Interrupting Rating of Breakers2006-12-26026 December 2006 Inadequate Fault Interrupting Rating of Breakers Information Notice 2004-01, Auxiliary Feedwater Pump Recirculation Line Orifice Fouling - Potential Common Cause Failure2004-01-21021 January 2004 Auxiliary Feedwater Pump Recirculation Line Orifice Fouling - Potential Common Cause Failure Information Notice 2003-19, Unanalyzed Condition of Reactor Coolant Pump Seal Leakoff Line During Postulated Fire Scenarios or Station Blackout2003-10-0606 October 2003 Unanalyzed Condition of Reactor Coolant Pump Seal Leakoff Line During Postulated Fire Scenarios or Station Blackout Information Notice 1999-28, Recall of Star Brand Fire Protection Sprinkler Heads1999-09-30030 September 1999 Recall of Star Brand Fire Protection Sprinkler Heads Information Notice 1999-27, Malfunction of Source Retraction Mechanism in Cobalt-60 Teletherapy Treatment Units1999-09-0202 September 1999 Malfunction of Source Retraction Mechanism in Cobalt-60 Teletherapy Treatment Units Information Notice 1999-26, Safety and Economic Consequences of Misleading Marketing Information1999-08-24024 August 1999 Safety and Economic Consequences of Misleading Marketing Information Information Notice 1999-25, Year 2000 Contingency Planning Activities1999-08-10010 August 1999 Year 2000 Contingency Planning Activities Information Notice 1999-24, Broad-Scope Licensees' Responsibilities for Reviewing and Approving Unregistered Sealed Sources and Devices1999-07-12012 July 1999 Broad-Scope Licensees' Responsibilities for Reviewing and Approving Unregistered Sealed Sources and Devices Information Notice 1999-23, Safety Concerns Related to Repeated Control Unit Failures of the Nucletron Classic Model High-Dose-Rate Remote Afterloading Brachytherapy Devices1999-07-0606 July 1999 Safety Concerns Related to Repeated Control Unit Failures of the Nucletron Classic Model High-Dose-Rate Remote Afterloading Brachytherapy Devices Information Notice 1999-20, Contingency Planning for the Year 2000 Computer Problem1999-06-25025 June 1999 Contingency Planning for the Year 2000 Computer Problem Information Notice 1999-21, Recent Plant Events Caused by Human Performance Errors1999-06-25025 June 1999 Recent Plant Events Caused by Human Performance Errors Information Notice 1999-22, 10CFR 34.43(a)(1); Effective Date for Radiographer Certification and Plans for Enforcement Discretion1999-06-25025 June 1999 10CFR 34.43(a)(1); Effective Date for Radiographer Certification and Plans for Enforcement Discretion Information Notice 1999-19, Rupture of the Shell Side of a Feedwater Heater at the Point Beach Nuclear Plant1999-06-23023 June 1999 Rupture of the Shell Side of a Feedwater Heater at the Point Beach Nuclear Plant Information Notice 1999-18, Update on Nrc'S Year 2000 Activities for Material Licensees and Fuel Cycle Licensees and Certificate Holders1999-06-14014 June 1999 Update on Nrc'S Year 2000 Activities for Material Licensees and Fuel Cycle Licensees and Certificate Holders Information Notice 1999-17, Problems Associated with Post-Fire Safe-Shutdown Circuit Analyses1999-06-0303 June 1999 Problems Associated with Post-Fire Safe-Shutdown Circuit Analyses Information Notice 1999-16, Federal Bureau of Investigation'S Nuclear Site Security Program1999-05-28028 May 1999 Federal Bureau of Investigation'S Nuclear Site Security Program Information Notice 1999-15, Misapplication for 10CFR Part 71 Transportation Shipping Cask Licensing Basis to 10CFR Part 50 Design Basis1999-05-27027 May 1999 Misapplication for 10CFR Part 71 Transportation Shipping Cask Licensing Basis to 10CFR Part 50 Design Basis Information Notice 1999-14, Unanticipated Reactor Water Draindown at Quad Cities Unit 2, Arkansas Nuclear One Unit 2, & FitzPatrick1999-05-0505 May 1999 Unanticipated Reactor Water Draindown at Quad Cities Unit 2, Arkansas Nuclear One Unit 2, & FitzPatrick Information Notice 1999-13, Insights from NRC Inspections of Low-and Medium-Voltage Circuit Breaker Maintenance Programs1999-04-29029 April 1999 Insights from NRC Inspections of Low-and Medium-Voltage Circuit Breaker Maintenance Programs Information Notice 1999-12, Year 2000 Computer Systems Readiness Audits1999-04-28028 April 1999 Year 2000 Computer Systems Readiness Audits Information Notice 1999-11, Incidents Involving the Use of Radioactive Iodine-1311999-04-16016 April 1999 Incidents Involving the Use of Radioactive Iodine-131 Information Notice 1999-08, Urine Specimen Adulteration1999-03-26026 March 1999 Urine Specimen Adulteration Information Notice 1999-09, Problems Encountered When Manually Editing Treatment Data on the Nucletron Microselectron-HDR (New) Model 105-9991999-03-24024 March 1999 Problems Encountered When Manually Editing Treatment Data on the Nucletron Microselectron-HDR (New) Model 105-999 Information Notice 1999-07, Failed Fire Protection Deluge Valves & Potential Testing Deficiencies in Preaction Sprinkler Systems1999-03-22022 March 1999 Failed Fire Protection Deluge Valves & Potential Testing Deficiencies in Preaction Sprinkler Systems Information Notice 1999-06, 1998 Enforcement Sanctions as a Result of Deliberate Violations of NRC Employee Protection Requirements1999-03-19019 March 1999 1998 Enforcement Sanctions as a Result of Deliberate Violations of NRC Employee Protection Requirements Information Notice 1999-06, 1998 Enforcement Sanctions As a Result of Deliberate Violations of NRC Employee Protection Requirements1999-03-19019 March 1999 1998 Enforcement Sanctions As a Result of Deliberate Violations of NRC Employee Protection Requirements Information Notice 1999-05, Inadvertent Discharge of Carbon Dioxide Fire Protection System and Gas Migration1999-03-0808 March 1999 Inadvertent Discharge of Carbon Dioxide Fire Protection System and Gas Migration Information Notice 1999-04, Unplanned Radiation Exposures to Radiographers, Resulting from Failures to Follow Proper Radiation Safety Procedures1999-03-0101 March 1999 Unplanned Radiation Exposures to Radiographers, Resulting from Failures to Follow Proper Radiation Safety Procedures Information Notice 1999-03, Exothermic Reactors Involving Dried Uranium Oxide Powder (Yellowcake)1999-01-29029 January 1999 Exothermic Reactors Involving Dried Uranium Oxide Powder (Yellowcake) Information Notice 1999-02, Guidance to Users on the Implementation of a New Single-Source Dose-Calculation Formalism and Revised Air-Kerma Strength Standard for Iodine-125 Sealed Sources1999-01-21021 January 1999 Guidance to Users on the Implementation of a New Single-Source Dose-Calculation Formalism and Revised Air-Kerma Strength Standard for Iodine-125 Sealed Sources Information Notice 1999-01, Deterioration of High-Efficiency Particulate Air Filters in a Pressurized Water Reactor Containment Fan Cooler Unit1999-01-20020 January 1999 Deterioration of High-Efficiency Particulate Air Filters in a Pressurized Water Reactor Containment Fan Cooler Unit Information Notice 1998-45, Cavitation Erosion of Letdown Line Orifices Resulting in Fatigue Cracking of Pipe Welds1998-12-15015 December 1998 Cavitation Erosion of Letdown Line Orifices Resulting in Fatigue Cracking of Pipe Welds Information Notice 1998-44, Ten-Year Inservice Inspection (ISI) Program Update for Licensees That Intend to Implement Risk-Informed ISI of Piping1998-12-10010 December 1998 Ten-Year Inservice Inspection (ISI) Program Update for Licensees That Intend to Implement Risk-Informed ISI of Piping Information Notice 1998-43, Leaks in Emergency Diesel Generator Lubricating Oil & Jacket Cooling Water Piping1998-12-0404 December 1998 Leaks in Emergency Diesel Generator Lubricating Oil & Jacket Cooling Water Piping Information Notice 1998-42, Implementation of 10 CFR 55.55a(g) Inservice Inspection Requirements1998-12-0101 December 1998 Implementation of 10 CFR 55.55a(g) Inservice Inspection Requirements Information Notice 1998-41, Spurious Shutdown of Emergency Diesel Generators from Design Oversight1998-11-20020 November 1998 Spurious Shutdown of Emergency Diesel Generators from Design Oversight Information Notice 1998-41, Spurious Shutdown of Emergency Diesel Generators From Design Oversight1998-11-20020 November 1998 Spurious Shutdown of Emergency Diesel Generators From Design Oversight Information Notice 1998-39, Summary of Fitness-for-Duty Program Performance Reports for Calendar Years 1996 and 19971998-10-30030 October 1998 Summary of Fitness-for-Duty Program Performance Reports for Calendar Years 1996 and 1997 Information Notice 1998-40, Design Deficiencies Can Lead to Reduced ECCS Pump Net Positive Suction Head During Design-Basis Accidents1998-10-26026 October 1998 Design Deficiencies Can Lead to Reduced ECCS Pump Net Positive Suction Head During Design-Basis Accidents Information Notice 1990-66, Incomplete Draining and Drying of Shipping Casks1998-10-25025 October 1998 Incomplete Draining and Drying of Shipping Casks Information Notice 1998-38, Metal-Clad Circuit Breaker Maintenance Issues Identified by NRC Inspections1998-10-15015 October 1998 Metal-Clad Circuit Breaker Maintenance Issues Identified by NRC Inspections Information Notice 1998-37, Eligibility of Operator License Applicants1998-10-0101 October 1998 Eligibility of Operator License Applicants Information Notice 1998-36, Inadequate or Poorly Controlled, Non-Safety-Related Maintenance Activities Unnecessarily Challenged Safety Systems1998-09-18018 September 1998 Inadequate or Poorly Controlled, Non-Safety-Related Maintenance Activities Unnecessarily Challenged Safety Systems Information Notice 1998-34, Configuration Control Errors1998-08-28028 August 1998 Configuration Control Errors Information Notice 1998-33, NRC Regulations Prohibit Agreements That Restrict or Discourage an Employee from Participating in Protected Activities1998-08-28028 August 1998 NRC Regulations Prohibit Agreements That Restrict or Discourage an Employee from Participating in Protected Activities Information Notice 1998-31, Fire Protection System Design Deficiencies and Common-Mode Flooding of Emergency Core Cooling System Rooms at Washington Nuclear Project Unit 21998-08-18018 August 1998 Fire Protection System Design Deficiencies and Common-Mode Flooding of Emergency Core Cooling System Rooms at Washington Nuclear Project Unit 2 2016-04-27
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
OFFICE OF NEW REACTORS
WASHINGTON, DC 20555-0001 July 26, 2011 NRC INFORMATION NOTICE 2011-17: CALCULATION METHODOLOGIES FOR
OPERABILITY DETERMINATIONS OF GAS
VOIDS IN NUCLEAR POWER PLANT PIPING
ADDRESSEES
All holders of, or applicants for, an operating license or construction permit for a nuclear power
reactor issued under Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic
Licensing of Production and Utilization Facilities, except those that have permanently ceased
operations and have certified that fuel has been permanently removed from the reactor vessel.
All holders of or applicants for an early site permit, standard design certification, standard
design approval, manufacturing license, or combined license under 10 CFR Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants.
PURPOSE
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform
addressees of recent instances of gas accumulation in safety-related systems in which the
resulting operability determination of the as-found condition relied on computer models that
were not demonstrated to be technically appropriate for the intended application.
Specifically, the computer models had not been sufficiently qualified by benchmarking against
test or plant data. The NRC expects that recipients will review the information for applicability to
their facilities and consider actions, as appropriate, to avoid similar problems. Suggestions
contained in this IN are not NRC requirements; therefore, no specific action or written response
is required.
BACKGROUND
Gas accumulation in systems that are designed to be full of water has been a longstanding
issue associated with commercial nuclear power plant operations. To address this problem, the
NRC issued Generic Letter (GL) 2008-01, Managing Gas Accumulation in Emergency Core
Cooling, Decay Heat Removal, and Containment Spray Systems, on January 11, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession
No. ML072910759). GL 2008-01 asked addressees to submit information to demonstrate that
the subject systems were in compliance with the current licensing and design bases and
applicable regulatory requirements, and that suitable design, operational, and testing control
measures were in place for maintaining this compliance.
ML11161A111 NRC Inspection Manual Temporary Instruction (TI) 2515/177, Managing Gas Accumulation in
Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems (NRC
Generic Letter 2008-01), dated June 9, 2009 (ADAMS Accession No. ML082950666), provided
background information and guidance for NRC inspectors to verify that the onsite
documentation, system hardware, and licensee actions are consistent with the information
provided in the licensees response to GL 2008-01.
For parts of a nuclear plant system that are filled with water as part of their design basis, a gas
void is considered a degraded or nonconforming condition or both that could potentially render
the system inoperable. When a gas void is identified, the operability of the system in its
as-found condition can be evaluated using NRC Inspection Manual, Part 9900, Technical
Guidance, Operability Determinations & Functionality Assessments for Resolution of Degraded
or Nonconforming Conditions Adverse to Quality or Safety, dated April 16, 2008 (ADAMS
Accession No. ML073531346).
The NRC Office of Nuclear Reactor Regulation (NRR) prepared, Guidance to
NRC/NRR/DSS/SRXB Reviewers for Writing Temporary Instruction (TI) 2515/177 Suggestions
for the Region Inspections, Revision 11, dated May 23, 2011 (ADAMS Accession
No. ML111660749), to offer further technical guidance for use by NRC inspectors when
inspecting licensee operability determinations associated with gas voids. It covers topics such
as void transport behavior and pump response to voids. NRR revises this guidance as needed
to provide NRC inspectors with the most recent insights such as knowledge gained through
industry response to GL 2008-01 and plans to place any future revisions under ADAMS
Package Accession No. ML112070155.
DESCRIPTION OF CIRCUMSTANCES
Millstone Power Station Unit 3
On October 20, 2008, with Millstone Power Station Unit 3 at zero percent power, as part of
GL 2008-01 activities, the licensee discovered a 15-percent gas void in the accessible portion of
the 24-inch-diameter pipe connecting the refueling water storage tank (RWST) to the
emergency core cooling system (ECCS) pumps. Licensee engineering staff determined that
under some postulated loss-of-coolant accident scenarios, the gas void could have been
transported to specific ECCS pumps, rendering them inoperable. The licensee determined the
cause to be a latent design error, as the system design did not account for the as-built pipe
deviation from horizontal that trapped gas in the 24-inch-diameter section of pipe. The pipe
should have had either a greater slope towards the RWST or a vent valve installed in the
24-inch-diameter section. Licensee corrective actions included installing a vent valve on this
line to provide a venting location.
The licensees thermal-hydraulic and void size modeling to assess operability used the RELAP5 computer code (licensee test results and analysis are publicly available under ADAMS
Accession Nos. ML091170150, ML091170137, and ML091870829). The licensee qualified the
use of the RELAP5 computer model through benchmarking against test data obtained using
mockups of the specific Millstone Unit 3 ECCS configuration to demonstrate applicability of the
RELAP5 computer model to the Millstone Unit 3 ECCS piping application. Where necessary, the licensee performed additional calculations to supplement the RELAP5 calculations to provide results consistent with the test data. Additional information appears in Millstone Unit 3 Licensee Event Report 05000423/2008-004-00, dated December 19, 2008 (ADAMS Accession
No. ML090070031).
The NRC inspected the licensees operability determination and identified no findings of
significance. Additional information appears in Millstone Unit 3 NRC Special Inspection Team
Report 05000423/2008010, dated March 23, 2009 (ADAMS Accession No. ML090820433).
Point Beach Nuclear Plant
On September 30, 2010, the NRC completed an inspection of Point Beach Units 1 and 2, which
included an inspection using TI 2515/177 as documented in Point Beach Units 1 and 2 NRC
Integrated Inspection Report 05000266/2010004; 05000301/2010004, dated November 9, 2010
(ADAMS Accession No. ML103130057). The NRC inspectors reviewed the licensees
procedures for conducting surveillances and determining void volumes to ensure that the void
criteria were satisfied and would be reasonably ensured to be satisfied until the next scheduled
void surveillance. The licensee established void volume acceptance criteria for piping system
high points to be used during field verifications. The void volumes were derived based on pipe
internal diameter and as-built slope, and internal height of the void. In addition, the licensee
relied on the use of the computer software GOTHIC to perform two-phase and two-component
analysis of gas movement to predict how a void volume in piping is translated into a transient
void fraction at the entrance of a pump following pump start. The licensee provided supporting
information that did not rely upon the GOTHIC computer model to demonstrate acceptability.
The NRC inspection report describes several issues related to whether the GOTHIC computer
model had been sufficiently qualified through benchmarking against test or plant data to
demonstrate the applicability of the computer model to the type of analysis being conducted, and the applicable terms, conditions and limitations for its use. While the licensee referenced
some testing to qualify the GOTHIC computer model for use in predicting quantitative void
transport behavior, the NRC inspection report provides examples of how the test configuration
and conditions differed from the actual plant configuration and conditions. The NRC inspection
report states that the inspectors discussed these observations with NRR and that it was
determined that these observations required further evaluation by NRR to better understand the
acceptability of the application of the test results. The licensee subsequently provided
supporting information that did not rely upon GOTHIC.
DISCUSSION
During the NRC staffs reviews of licensee responses to GL 2008-01 and subsequent NRC
inspections, the NRC reviewed instances of gas accumulation in safety-related systems in
which the resulting operability determination of the as-found condition relied on a computer
model that was not demonstrated to be technically appropriate for the intended application.
Specifically, the computer model had not been acceptably qualified by benchmarking against
test and plant data to demonstrate its applicability to the type of analysis being conducted, and
the applicable terms, conditions and limitations for its use. This, along with basing analyses on
inappropriate pump suction void criteria, could result in licensees establishing inappropriate or
unsupported values for gas void volumes that could impact system operability. The above example of Millstone Unit 3 illustrates a case where a licensee acceptably qualified
the use of a computer model (RELAP5) to assess past ECCS operability in response to a gas
void the licensee discovered. This benchmarking, and therefore the applicability, of the
RELAP5 computer model for predicting gas transport was limited to the Millstone Unit 3 piping
application. Conversely, the above example at Point Beach describes issues related to whether
the GOTHIC computer model had been acceptably qualified through benchmarking to
demonstrate applicability for the specific application. Qualification issues also exist for other
calculation methodologies such as other computer programs and manual calculation methods.
CONTACT
This IN requires no specific action or written response. Please direct any questions about this
matter to the technical contacts listed below or to the appropriate project manager.
/RA/ /RA/
Timothy J. McGinty, Director Laura A. Dudes, Director
Division of Policy and Rulemaking Division of Construction Inspection and
Office of Nuclear Reactor Regulation Operational Programs
Office of New Reactors
Technical Contacts: Warren Lyon, NRR Jennifer Gall, NRR
301-415-2897 301-415-3253 E-mail: warren.lyon@nrc.gov E-mail: jennifer.gall@nrc.gov
Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under NRC Library..
ML11161A111 TAC ME6570
OFFICE NRR/DSS/SRXB NRR/DSS/SRXB ADM/DAS/PB NRR/DSS/SRXB
NAME JGall WLyon KAzariah-Kribbs AUlses
DATE 7/18/11 7/18/11 7/12/11 e-mail 7/18/11 OFFICE NRR/DSS NRO/DSRA/SRSB NRR/DPR/PGCB NRR/DPR/PGCB
NAME SBahadur JDonoghue IFrankl for DBeaulieu CHawes CMH
DATE 7/19/11 7/13/11 7/25/11 7/26/11 OFFICE NRR/DPR/PGCB NRO/DCIP NRR/DPR
NAME SRosenberg LDudes TMcGinty
OFFICE 7/26/11 7/26/11 7/26/11
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list | - Information Notice 2011-01, Commercial Grade Dedication Issues Identified During NRC Inspections (15 February 2011, Topic: Commercial Grade Dedication)
- Information Notice 2011-02, Operator Performance Issues Involving Reactivity Management at Nuclear Power Plants (31 January 2011, Topic: Downpower)
- Information Notice 2011-03, Nonconsecutive Criticality Safety Analyses for Fuel Storage (16 February 2011, Topic: Nonconservative Technical Specifications)
- Information Notice 2011-03, Nonconsecutive Criticality Safety analyses for Fuel Storage (16 February 2011, Topic: Nonconservative Technical Specifications)
- Information Notice 2011-04, in: Contaminants and Stagnant Conditions Affecting Stress Corrosion Cracking in Stainless Steel Piping in Pressurized Water Reactors (23 February 2011, Topic: Boric Acid)
- Information Notice 2011-04, In: Contaminants and Stagnant Conditions Affecting Stress Corrosion Cracking in Stainless Steel Piping in Pressurized Water Reactors (23 February 2011, Topic: Boric Acid)
- Information Notice 2011-04, IN: Contaminants and Stagnant Conditions Affecting Stress Corrosion Cracking in Stainless Steel Piping in Pressurized Water Reactors (23 February 2011, Topic: Boric Acid)
- Information Notice 2011-05, Tohoku-Taiheiyou-Oki Earthquake Effects on Japanese Nuclear Power Plants (18 March 2011, Topic: Boric Acid, B.5.b Mitigating Strategies, Earthquake)
- Information Notice 2011-07, Specific License Required When Exporting To Embargoed Destinations Listed In 10 CFR 110.28 (14 April 2011, Topic: Moisture Density Gauge)
- Information Notice 2011-08, Tohoku-Taiheiyou-Oki Earthquake Effects on Japanese Nuclear Power Plants - for Fuel Cycle Facilities (31 March 2011, Topic: Boric Acid, Earthquake)
- Information Notice 2011-10, Thermal Issues Identified During Loading of Spent Fuel Storage Casks (2 May 2011, Topic: Fuel cladding)
- Information Notice 2011-11, Heat and Smoke Detector Requirements for 10 CFR Part 36 Irradiators (27 April 2011, Topic: Pandemic)
- Information Notice 2011-12, Reactor Trips Resulting from Water Intrusion Into Electrical Equipment (16 June 2011, Topic: Preliminary White Finding)
- Information Notice 2011-12, Reactor Trips Resulting from Water Intrusion into Electrical Equipment (16 June 2011, Topic: Preliminary White Finding)
- Information Notice 2011-13, OFFICIAL EXHIBIT - NYS000329-00-BD01 - NRC Information Notice 2011-13, Control Rod Blade Cracking Resulting in Reduced Design Lifetime (Jun 29, 2011) (NRC in 2011-13) (29 June 2011, Topic: Shutdown Margin)
- Information Notice 2011-13, Official Exhibit - NYS000329-00-BD01 - NRC Information Notice 2011-13, Control Rod Blade Cracking Resulting in Reduced Design Lifetime (Jun 29, 2011) (NRC in 2011-13) (29 June 2011, Topic: Shutdown Margin)
- Information Notice 2011-13, Official Exhibit - Nys000329-00-Bd01 - NRC Information Notice 2011-13, Control Rod Blade Cracking Resulting in Reduced Design Lifetime (Jun 29, 2011) (Nrc in 2011-13) (29 June 2011, Topic: Shutdown Margin)
- Information Notice 2011-14, Component Cooling Water System Gas Accumulation and Other Performance Issues (18 July 2011, Topic: Unanalyzed Condition, Preliminary White Finding)
- Information Notice 2011-15, Steel Containment Degradation and Associated License Renewal Aging Management Issues (1 August 2011, Topic: Coatings, Incorporated by reference, Aging Management, Moisture barrier)
- Information Notice 2011-17, Calculation Methodologies for Operability Determinations of Gas Voids in Nuclear Power Plant Piping (26 July 2011, Topic: Functionality Assessment)
- Information Notice 2011-19, Licensee Event Reports Containing Information Pertaining to Defects to Basic Components (26 September 2011)
- Information Notice 2011-20, NRC060 - NRC Information Notice 2011-20: Concrete Degradation by Alkali-Silica Reaction (Nov. 18, 2011) (24 July 2019, Topic: Aging Management)
- Information Notice 2011-21, Realistic Emergency Core Cooling System Evaluation Model Effects Resulting From Nuclear Fuel Thermal Conductivity Degradation (13 December 2011, Topic: Fuel cladding)
- Information Notice 2011-21, Realistic Emergency Core Cooling System Evaluation Model Effects Resulting from Nuclear Fuel Thermal Conductivity Degradation (13 December 2011, Topic: Fuel cladding)
- Information Notice 2011-22, Instrumentation & Control Module Failures, Incorrect Configurations and Settings (21 December 2011)
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