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Category:NRC Information Notice
MONTHYEARML19196A2452019-07-15015 July 2019 Public Notice - Sequoyah Nuclear Plant, Unit 2 - Exigent Amendment to Facility Operating License Information Notice 2019-01, Inadequate Evaluation of Temporary Alterations2019-03-12012 March 2019 Inadequate Evaluation of Temporary Alterations Information Notice 2015-05, Inoperability Of Auxiliary And Emergency Feedwater Auto Start Circuits On Loss Of Main Feedwater Pumps2015-05-12012 May 2015 Inoperability Of Auxiliary And Emergency Feedwater Auto Start Circuits On Loss Of Main Feedwater Pumps Information Notice 2015-05, Inoperability of Auxiliary and Emergency Feedwater Auto Start Circuits on Loss of Main Feedwater Pumps2015-05-12012 May 2015 Inoperability of Auxiliary and Emergency Feedwater Auto Start Circuits on Loss of Main Feedwater Pumps Information Notice 1991-09, Counterfeiting of Crane Valves2007-09-25025 September 2007 Counterfeiting of Crane Valves Information Notice 2003-02, Recent Experience with Reactor Coolant System Leakage & Boric Acid Corrosion2003-01-16016 January 2003 Recent Experience with Reactor Coolant System Leakage & Boric Acid Corrosion Information Notice 2002-22, Degraded Bearing Surfaces in Gm/Emd Emergency Diesel Generators2002-06-28028 June 2002 Degraded Bearing Surfaces in Gm/Emd Emergency Diesel Generators 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 1998-33, 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 1998-34, Configuration Control Errors1998-08-28028 August 1998 Configuration Control Errors 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 2019-07-15
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, DC 20555-0001 January 16, 2003 NRC INFORMATION NOTICE 2003-02: RECENT EXPERIENCE WITH REACTOR
COOLANT SYSTEM LEAKAGE AND BORIC ACID
CORROSION
Addressees
All holders of operating licenses or construction permits for pressurized water reactors (PWRs).
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to inform
addressees of recently observed reactor coolant leakage at two pressurized water reactor
facilities, one of which resulted in the subsequent degradation of the reactor pressure vessel
head. It is expected that recipients will review the information for applicability to their facilities
and consider actions, as appropriate, to avoid similar problems. However, suggestions in this
information notice are not NRC requirements; therefore no specific action or written response is
required.
Description of Circumstances
Sequoyah Unit 2
On December 26, 2002, the unit tripped from full power as a result of low reactor coolant
system (RCS) flow due to a ground fault in a reactor coolant pump motor winding. In the
ensuing shutdown to correct the pump problem, the licensee initiated a search to locate and
correct a suspected RCS leak that, prior to the trip, had resulted in elevated moisture and
activity levels inside containment. During this inspection, the licensee identified an
accumulation of boric acid on the reactor vessel head insulation that resulted from a leaking
reactor vessel level indication system (RVLIS) compression fitting. The leakage had seeped
through a seam in the insulation onto the reactor pressure vessel (RPV) head and resulted in
minor boric acid corrosion of the head. This RVLIS compression fitting had been disconnected
and reconnected during the May 2002 refueling outage. The licensee also identified a small
leak through a canopy seal weld on an empty control rod drive mechanism (CRDM) penetration
that did not result in any boric acid corrosion of the reactor vessel head.
Based on the location of the leaking RVLIS fitting, the temperature of the leakage fluid was
close to the ambient temperature outside the vessel insulation. The licensee estimated the
mass of boric acid crystals on this insulation surface at about 9 kilograms (20 pounds). A seam
in the insulation was in this area. On removing the insulation and cleaning the area, the
licensee observed boric acid corrosion of the head near the flange. The licensee determined
that the amount of material loss from the head was small, in the shape of a groove less than
one centimeter (cm) [0.3 inch] wide, about twelve cm [4.6 inches] long, and at most about one- third cm [0.125 inch] deep.
The licensees evaluation indicated that 98 percent or better of the structural wall remained
intact and that no abrupt corners existed in the degraded area. The licensee justified continued
operation based on the minor extent of the degradation.
Comanche Peak Unit 1
On November 30, 2002, a control rod dropped into the core. The licensee suspected a fault in
the CRDM coils. Failing to identify the cause of the dropped rod while at reduced power, the
licensee decided to shut down. While continuing to troubleshoot the CRDM problem in Mode 3, the licensee observed a leak around the CRDM housing. The leak was from a CRDM canopy
seal weld. Water from the leaking canopy seal weld apparently entered the CRDM coils, causing coil failure. Boric acid crystals were found around the leak site, on the vessel head
insulation, and on the reactor pressure vessel head. The licensee repaired the canopy weld
with a weld overlay and cleaned the CRDM housing, the head insulation, and the head to
remove the boric acid deposits. The amount of boric acid crystals recovered from the head was
about 1 kilogram (2 pounds). The licensee did not find any reactor coolant pressure boundary
degradation.
Other operating experiences of similar character may be found in the generic communications
listed in NRC Bulletin 2002-01, Reactor Pressure Vessel Head Degradation and Reactor
Coolant Pressure Boundary Integrity.
Discussion
A number of mechanical and welded connections exist above the reactor pressure vessel head
that, historically, have leaked at a number of plants. This leakage of borated water may lead to
degradation of the low alloy steel reactor vessel head by boric acid corrosion. At Sequoyah
Unit 2, the leakage resulted in relatively minor degradation of the reactor vessel head. At
Comanche Peak Unit 1, the leakage resulted in no apparent degradation of the RCS pressure
boundary. In the Sequoyah Unit 2 and Comanche Peak Unit 1 events, the unidentified reactor
coolant leakage had not shown a discernible increase from the very low levels that typically
occur at a PWR facility.
Common assumptions that RCS leakage onto a hot surface, such as the reactor pressure
vessel head, will not cause corrosion may not be justified and are the subject of ongoing
research. Usually, small quantities of water coming into contact with a surface as hot as the
reactor vessel head would be expected to flash and leave a noncorrosive dry boric acid residue
on the surface. However, at Sequoyah Unit 2 the resulting condition produced an environment
in which boric acid corrosion could occur. This experience challenges current assumptions with
respect to the potential effects of RCS leakage. The NRC is continuing to consider the safety
and regulatory aspects of this experience. This information notice requires no specific action or written response. If you have any
questions about the information in this notice, please contact the technical contact listed below
or the appropriate project manager from the NRCs Office of Nuclear Reactor Regulation
(NRR).
/RA/
William D. Beckner, Program Director
Operating Reactor Improvements Program
Division of Regulatory Improvement Programs
Office of Nuclear Reactor Regulation
Technical contacts: V. Hodge, NRR E. Sullivan, NRR
301-415-1861 301-415-2796 E-mail: cvh@nrc.gov E-mail: ejs@nrc.gov
Attachment: List of Recently Issued NRC Information Notices
ML030160004 DOCUMENT NAME: C:\ORPCheckout\FileNET\ML030160004.wpd
INDICATE IN BOX: C=COPY W/O ATTACHMENT/ENCLOSURE, E=COPY W/ATT/ENCL, N=NO COPY
OFFICE RORP:DRIP EMCB:DE EMCB:DE EMCB:DE
NAME VHodge TSullivan SCoffin BBateman
DATE 01/13/03* 01/13/03* 01/14/03* 01/15/03 OFFICE DLPM:PD-2 RORP:DRIP RORP
NAME AHowe TReiss BBeckner
DATE 01/14/03* 01/15/03 01/16/03
Attachment 1 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
_____________________________________________________________________________________
Information Date of
Notice No. Subject Issuance Issued to
_____________________________________________________________________________________
2003-01 Failure of a Boiling Water 01/15/2003 All holders of operating licenses
Reactor Target Rock Main or construction permits for
Steam Safety/Relief Valve nuclear power reactors, except
those that have permanently
ceased operations and have
certified that fuel has been
permanently removed from the
reactor.
2002-35 Changes to 10 CFR Parts 71 12/20/2002 All holders of 10 CFR Part 71 and 72 Quality Assurance quality assurance program
Programs approvals and all 10 CFR Part 72 licensees and certificate holders.
2002-34 Failure of Safety-Related 11/25/2002 All holders of operating licenses
Circuit Breaker External or construction permits for
Auxiliary Switches at Columbia nuclear power reactors.
Generating Station
2002-33 Notification of Permanent 11/21/2002 All teletherapy and radiation
Injunction Against Neutron processing licensees.
Products Incorporated of
Dickerson, Maryland
2002-29 Recent Design Problems in 11/06/2002 All holders of operating licenses
(Errata) Safety Functions of Pneumatic or construction permits for
Systems nuclear power reactors.
2002-32 Electromigration on 10/31/2002 All holders of operating licenses
Semiconductor Integrated for nuclear power reactors except
Circuits those who have ceased
operations and have certified that
fuel has been permanently
removed from the reactor vessel.
Note: NRC generic communications may be received in electronic format shortly after they are
issued by subscribing to the NRC listserver as follows:
To subscribe send an e-mail to <listproc@nrc.gov >, no subject, and the following
command in the message portion:
subscribe gc-nrr firstname lastname
______________________________________________________________________________________
OL = Operating License
CP = Construction Permit
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list | - Information Notice 2003-01, Failure of a Boiling Water Reactor Target Rock Main Steam Safety/Relief Valve (15 January 2003, Topic: Uranium Hexafluoride)
- Information Notice 2003-02, Recent Experience with Reactor Coolant System Leakage & Boric Acid Corrosion (16 January 2003, Topic: Boric Acid, Weld Overlay)
- Information Notice 2003-03, Part 21 - Inadequately Staked Capscrew Renders Residual Heat Removal Pump Inoperable (27 January 2003, Topic: Boric Acid)
- Information Notice 2003-04, Summary of Fitness-For-Duty Program Performance Reports for Calendar Year 2000 (6 February 2003, Topic: Boric Acid, Fitness for Duty)
- Information Notice 2003-06, Failure of Safety-Related Linestarter Relays at San Onofre Nuclear Generating Station (19 June 2003)
- Information Notice 2003-08, Potential Flooding Through Unsealed Concrete Floor Cracks (25 June 2003)
- Information Notice 2003-09, Source Positioning Errors and System Malfunctions Administration of Intravascular Brachytherapy (16 July 2003, Topic: Brachytherapy, Uranium Hexafluoride)
- Information Notice 2003-11, Leakage Found on Bottom-Mounted Instrumentation Nozzles (8 January 2004, Topic: Unanalyzed Condition, Nondestructive Examination, Stress corrosion cracking, Eddy Current Testing)
- Information Notice 2003-12, Problems Involved In Monitoring Dose to Hands Resulting from Handling of Radiopharmaceuticals (22 August 2003, Topic: Uranium Hexafluoride, Power Uprate)
- Information Notice 2003-12, Problems Involved in Monitoring Dose to Hands Resulting from Handling of Radiopharmaceuticals (22 August 2003)
- Information Notice 2003-13, Steam Generator Tube Degradation at Diablo Canyon (28 August 2003)
- Information Notice 2003-14, Potential Vulnerability of Plant Computer Network to Worm Infection (29 August 2003)
- Information Notice 2003-15, Importance of Followup Activities in Resolving Maintenance Issues (5 September 2003)
- Information Notice 2003-17, Reduced Service Life of Automatic Switch Company (ASCO) Solenoid Valves With Buna-N Material (29 September 2003)
- Information Notice 2003-17, Reduced Service Life of Automatic Switch Company (Asco) Solenoid Valves with Buna-N Material (29 September 2003)
- Information Notice 2003-18, General Electric Type Sbm Control Switches with Defective Cam Followers (26 September 2003)
- Information Notice 2003-18, General Electric Type SBM Control Switches with Defective Cam Followers (26 September 2003)
- Information Notice 2003-19, Unanalyzed Condition of Reactor Coolant Pump Seal Leakoff Line During Postulated Fire Scenarios or Station Blackout (6 October 2003, Topic: Safe Shutdown, Unanalyzed Condition, Boric Acid)
- Information Notice 2003-20, Derating Whiting Cranes Purchased Before 1980 (22 October 2003, Topic: Unanalyzed Condition)
- Information Notice 2003-21, High-Dose-Rate-Remote-Afterloader Equipment Failure (24 November 2003, Topic: Unanalyzed Condition, Brachytherapy)
- Information Notice 2003-22, Heightened Awareness for Patients Containing Detectable Amounts of Radiation from Medical Administrations (9 December 2003, Topic: Unanalyzed Condition, Brachytherapy)
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