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Category:NRC Information Notice
MONTHYEARInformation Notice 1991-09, Counterfeiting of Crane Valves2007-09-25025 September 2007 Counterfeiting of Crane Valves Information Notice 2007-28, Potential Common Cause Vulnerabilities in Essential Service Water Systems Due to Inadequate Chemistry Controls2007-09-19019 September 2007 Potential Common Cause Vulnerabilities in Essential Service Water Systems Due to Inadequate Chemistry Controls Information Notice 2006-04, Design Deficiency in Pressurizer Heaters for Pwrs2006-02-13013 February 2006 Design Deficiency in Pressurizer Heaters for Pwrs Information Notice 2006-04, Design Deficiency in Pressurizer Heaters for PWRs2006-02-13013 February 2006 Design Deficiency in Pressurizer Heaters for PWRs Information Notice 2005-15, Three-Unit Trip and Loss of Offsite Power at Palo Verde Nuclear Generating Station2005-06-0101 June 2005 Three-Unit Trip and Loss of Offsite Power at Palo Verde Nuclear Generating Station 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 Information Notice 1998-30, Effect of Year 2000 Computer Problem on NRC Licensees and Certificate Holders1998-08-12012 August 1998 Effect of Year 2000 Computer Problem on NRC Licensees and Certificate Holders Information Notice 1998-29, Predicted Increase in Fuel Rod Cladding Oxidation1998-08-0303 August 1998 Predicted Increase in Fuel Rod Cladding Oxidation 2007-09-25
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001 September 19, 2007 NRC INFORMATION NOTICE 2007-28: POTENTIAL COMMON CAUSE
VULNERABILITIES IN ESSENTIAL SERVICE
WATER SYSTEMS DUE TO INADEQUATE
CHEMISTRY CONTROLS
ADDRESSEES
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.
PURPOSE
The U.S. Nuclear Regulatory Commission (NRC) is issuing this Information Notice (IN) to
inform addressees of the importance of maintaining essential service water (ESW) systems in a
manner that precludes the development of potential common cause failure vulnerabilities due to
inadequate water chemistry controls. 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 contained in this IN are not NRC requirements; therefore, no specific
action or written response is required.
DESCRIPTION OF CIRCUMSTANCES
On May 17, 2006, the licensee at the Palo Verde Nuclear Generating Station (Palo Verde)
noted elevated temperatures in the intake air for emergency diesel generator (EDG) 2B while
the engine was running for a surveillance test. The engine intake air is compressed and heated
by the turbocharger and is then cooled by two parallel intercoolers before entering the engine.
The elevated temperatures were noted at the outlet of the intercoolers, which was indicative of
inadequate cooling in the intercoolers.
The licensee inspected the EDG 2B intercoolers and found fouling/scaling on the cooling water
(spray pond system) side with a white lotion-like substance. In addition to providing the cooling
water to all the EDG coolers (two intercoolers, a jacket water cooler, and a lube oil cooler), the
emergency spray pond system provides cooling to the essential cooling water (EW) system
heat exchanger.
The Unit 2 EW heat exchangers were also taken out of service for inspection and tube
cleaning. Similarly to the EDG intercoolers, they were found to have fouling/scaling that was
reducing the heat transfer capabilities of the heat exchanger tubes.
The licensee determined that the failure to properly maintain water chemistry in the Palo Verde
cooling water spray ponds led to extensive fouling/scaling of the interior surfaces of heat
exchanger tubes. The degraded heat transfer capabilities in the EDG coolers and the EW heat
exchangers occurred in all trains in all units. The degree of degradation varied among the
units. The EDG intercoolers and the EW heat exchangers were observed to have the most
fouling/scaling; the jacket water and lube oil coolers fouling/scaling was minor and had no
impact on operability. The difference in the amount of fouling/scaling was due to the fact that
the heat exchanger tube skin temperatures were the highest for the EDG intercoolers followed
by the EW heat exchangers. As the heat exchanger tube skin temperature increases, the rate
of scaling increases.
Samples of the heat exchanger deposits at Palo Verde were analyzed and determined to be an
amorphous mix of a number of substances. The major constituents were determined to be
zinc, phosphorous, and calcium. The insulating film on the heat exchanger tubes included a
zinc-hydroxide film, scale (calcium phosphate or calcium carbonate) and precipitant
(calcium-zinc-phosphate). (Calcium is the major constituent of scale, which is contained in the
makeup water source, unless the plant uses deionized or pure water. Calcium carbonate and
calcium phosphate are common scale constituents. The zinc and phosphorous were from the
scale/corrosion inhibitor that normally plates out on the surface in very small amounts).
The licensees root cause assessment concluded that improper chemical control resulted in an
insulating precipitant on the spray pond side of the heat exchanger surfaces. The improper
chemistry control was a result of not enough dispersant, high pH, and improperly blowing down
(feed and bleed) of the spray pond. The licensee personnel thought the spray pond had
enough dispersant based on sample analysis; however, most dispersants blend a tracer
chemical such as molybdenum (very minimal degradation with time) which provides an
equivalent dispersant concentration for a fully active dispersant. Dispersants on average will
last only 3 - 5 days when added to a cooling water system, and if stressed by temperature or
other environmental conditions, will degrade more rapidly. Another important factor was that
licensee personnel were not aware of the need to blowdown the system. As the water
evaporated, all the incoming non-volatile contaminates, such as calcium, magnesium, and
phosphorus, remained in the spray pond, thereby, concentrating and causing the system to
become more prone to scale formation.
The licensees chemistry personnel implementing the spray pond chemistry control program did
not fully understand how the chemicals being added to the spray pond interacted with each
other. As a result, the licensee implemented a series of inappropriate changes to the chemistry
limits that negatively impacted solubility of critical materials without a clear assessment or
understanding of the potential impacts of the changes.
Chemistry personnel did not adequately monitor the effectiveness of the anti-fouling portion of
the essential spray pond chemistry regime. As a result, chemical precipitation occurred
throughout the system. Accumulation of chemicals, impurities, and sediment in the spray
ponds hindered chemistry control measures, affected thermal capacity and interfered with the
stations ability to assess structural integrity. The NRC dispatched a special inspection team to review the details surrounding the event.
This issue is discussed in more detail in Palo Verde Nuclear Generating Station, Units 1, 2, and 3 - NRC Special Inspection Report 05000528/2006011; 05000529/2006011;
05000530/2006011, dated September 28, 2006, Agencywide Documents Access and
Management System (ADAMS) Accession Number ML062710607. NRC letter Final
Significance Determination, dated December 22, 2006, ADAMS Accession No. ML063600175, determined that a non-cited violation of technical specifications occurred because train B of the
essential cooling water system in Unit 2 was not capable of performing its safety function and
that the degraded performance was due to fouling caused by improper chemical addition in the
associated spray pond.
BACKGROUND
The ESW system (or its equivalent) for U.S. commercial reactor plants is the assured, safety-related means of transferring decay heat from the reactor coolant system to the ultimate
heat sink. The ESW system is also relied upon for other critical safety functions, such as
(1) providing cooling water for most of the essential, safety-related equipment used for
mitigating plant accident and transient conditions, (2) reactor coolant pump seal cooling,
(3) spent fuel pool cooling, and (4) dissipating sensible and reactor decay heat during shutdown
conditions.
ESW systems for U.S. nuclear power plants are generally unique from one plant to another.
However, the ESW systems typically include a water source (such as a pond or cooling tower
basin) where chemicals are added to inhibit internal corrosion of the piping, scale formation, algae/biological growth, and maintain pH within desired ranges, etc. Scale formation increases
with increased heat exchanger skin temperature, reduced water velocity, higher pH, and a
dirty water source (e.g., higher concentrations of chemicals such as calcium and magnesium).
Plant-specific probabilistic risk assessments have shown that the loss of the ESW system may
be a significant contributor to the potential for a core damage accident.
Related Generic Communications
NRC Generic Letter (GL) 89-13, Service Water System Problems Affecting Safety-Related
Equipment, dated July 18, 1989, requested specific licensee actions to resolve service water
(SW) system problems. In particular, this GL recommended that licensees ensure (by a routine
inspection and maintenance program for open-cycle SW system piping and components) that
corrosion, erosion protective coating failure, silting, and biofouling cannot degrade the
performance of safety-related systems supplied by SW.
NRC IN 2006-17, Recent Operating Experience Of Service Water Systems Due To External
Conditions, dated July 31, 2006, alerted licensees to blockages in SW systems due to external
conditions such as silt, sand, grass, frazil ice, and fish.
NRC IN 2007-06, Potential Common Cause Vulnerabilities in Essential Service Water
Systems, dated February 9, 2007, alerted licensees to events where corrosion of SW piping and pitting due to microbiological-induced corrosion affected the structural integrity of the SW
system.
DISCUSSION
The above Palo Verde event illustrates the importance of maintaining ESW systems in a
manner that precludes the development of potential common cause failure vulnerabilities due to
inadequate water chemistry. Licensees are required to have an operable ESW system as
specified in plant technical specifications. In addition, licensees are required to satisfy the
requirements in Title 10 of the Code of Federal Regulations (10 CFR) Part 50 to ensure:
changes to chemistry procedures are adequately evaluated with respect to fouling and scaling
so that ESW system heat exchangers meet design basis requirements; and, testing is
adequate to identify an unacceptable degree or rate of heat exchanger degradation while
providing for the timely evaluation of test results to allow for timely corrective actions.
CONTACT
This information notice requires no specific action or written response. Please direct any
questions about this matter to the technical contacts listed below or the appropriate Office of
Nuclear Reactor Regulation (NRR) project manager.
/RA by TQuay for/
Michael J. Case, Director
Division of Policy and Rulemaking
Office of Nuclear Reactor Regulation
Technical Contacts: John P. Burke, NRR/DCI Brett A. Rini, NRR/IOEB
301-415-1529 301-415-3931 E-mail: jpb3@nrc.gov E-mail: bar3@nrc.gov
Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov under Electronic Reading Room/Document Collections. and pitting due to microbiological-induced corrosion affected the structural integrity of the SW
system.
DISCUSSION
The above Palo Verde event illustrates the importance of maintaining ESW systems in a
manner that precludes the development of potential common cause failure vulnerabilities due to
inadequate water chemistry. Licensees are required to have an operable ESW system as
specified in plant technical specifications. In addition, licensees are required to satisfy the
requirements in Title 10 of the Code of Federal Regulations (10 CFR) Part 50 to ensure:
changes to chemistry procedures are adequately evaluated with respect to fouling and scaling
so that ESW system heat exchangers meet design basis requirements; and, testing is
adequate to identify an unacceptable degree or rate of heat exchanger degradation while
providing for the timely evaluation of test results to allow for timely corrective actions.
CONTACT
This information notice requires no specific action or written response. Please direct any
questions about this matter to the technical contacts listed below or the appropriate Office of
Nuclear Reactor Regulation (NRR) project manager.
/RA by TQuay for/
Michael J. Case, Director
Division of Policy and Rulemaking
Office of Nuclear Reactor Regulation
Technical Contacts: John P. Burke, NRR/DCI Brett A. Rini, NRR/IOEB
301-415-1529 301-415-3931 E-mail: jpb3@nrc.gov E-mail: bar3@nrc.gov
Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov under Electronic Reading Room/Document Collections.
DISTRIBUTION:
IN Reading File
ADAMS ACCESSION NO. ML071920514 OFFICE DIRS:IOEB TECH EDITOR CSGB:DCI PGCB:DPR:PM PGCB:DPR:LA BC:IOEB:DIRS
NAME BRini LCulp by email JBurke DBeaulieu CHawes MJRoss-Lee
DATE 7/31/07 7/3/07 7/31/07 9 /10/07 09/05/07 8/7/07 OFFICE BC:CSGB:DCI BC:PGCB:DPR D:DPR
NAME AHiser MMurphy MCase
DATE 8/2/07 09/17/07 9/19/07 OFFICIAL RECORD COPY
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list | - Information Notice 2007-03, Reportable Medical Events Involving Patients Receiving Dosages of Sodium Iodide Iodine-131 Less than the Prescribed Dosage Because of Capsules Remaining in Vials After Administration (2 February 2007, Topic: Enforcement Discretion)
- Information Notice 2007-03, Reportable Medical Events Involving Patients Receiving Dosages of Sodium Iodide Iodine-131 Less Than the Prescribed Dosage Because of Capsules Remaining in Vials After Administration (2 February 2007, Topic: Tritium Exit Sign)
- Information Notice 2007-04, Construction Experience Related to the Assurance of Quality in the Construction of Nuclear Power Plants (5 February 2007)
- Information Notice 2007-05, Vertical Deep Draft Pump Shaft and Coupling Failures (9 February 2007, Topic: Ultimate heat sink)
- Information Notice 2007-06, Potential Common Cause Vulnerabilities in Essential Service Water Systems (9 February 2007, Topic: Ultimate heat sink, Probabilistic Risk Assessment, Coatings, Biofouling, Through-Wall Leak)
- Information Notice 2007-07, Potential Failure of All Control Rod Groups to Insert in a Boiling Water Reactor (BWR) Due to a Fire (15 February 2007, Topic: Hot Short, Safe Shutdown, Shutdown Margin, Fire Protection Program, Backfit)
- Information Notice 2007-08, Potential Vulnerabilities of Time-Reliant Computer-Based Systems Due to Change in Daylight Saving Time Dates (28 February 2007)
- Information Notice 2007-09, Equipment Operability Under Degraded Voltage Conditions (26 March 2007)
- Information Notice 2007-10, Yttritium-90 TheraSpheres and SirSpheres Impurities (2 March 2007, 15 March 2007, Topic: Tritium Exit Sign, TheraSphere)
- Information Notice 2007-10, Yttritium-90 Theraspheres and Sirspheres Impurities (2 March 2007, Topic: Enforcement Discretion, TheraSphere)
- Information Notice 2007-11, Recent Operator Performance Issues at Nuclear Power Plants (6 March 2007, Topic: Time of Discovery)
- Information Notice 2007-12, Tactical Communications Interoperability Between Nuclear Power Reactor Licensees and First Responders (15 March 2007)
- Information Notice 2007-14, Loss of Offsite Power and Dual-Unit Trip at Catawba Nuclear Generating Station (30 March 2007)
- Information Notice 2007-15, Effects of Ethernet-based, Non-Safety Related Controls on the Safe and Continued Operation of Nuclear Power Stations (17 April 2007)
- Information Notice 2007-17, Fires at Nuclear Power Plants Involving Inadequate Fire Protection Administrative and Design Controls (3 May 2007, Topic: Safe Shutdown, Fire Barrier, Operator Manual Action, Continuous fire watch, Fire Protection Program, Fire Watch, Hourly Fire Watch)
- Information Notice 2007-18, Operating Experience Regarding Entrainment of Gas or Debris Into Auxiliary Feedwater Systems (13 May 2007, Topic: Design basis earthquake)
- Information Notice 2007-18, Operating Experience Regarding Entrainment of Gas or Debris into Auxiliary Feedwater Systems (13 May 2007, Topic: Foreign Material Exclusion)
- Information Notice 2007-20, Use of Blank Ammunition (11 June 2007)
- Information Notice 2007-21, Pipe Wear Due to Interaction of Flow-Induced Vibration and Reflective Metal Insulation (11 December 2020, Topic: VT-2, Liquid penetrant)
- Information Notice 2007-22, Recent Hydrogen Fluoride Exposures at Fuel Cycle Facilities (19 June 2007, Topic: Uranium Hexafluoride, TheraSphere)
- Information Notice 2007-23, Inadvertent Discharge of Halon 1301 Fire Suppression System Due to Incorrect and/or Out of Date Procedures (8 August 2007, Topic: Fire Protection Program)
- Information Notice 2007-23, Inadvertent Discharge of Halon 1301 Fire Suppression System Due to Incorrect And/Or Out of Date Procedures (8 August 2007, Topic: Fire Protection Program, TheraSphere)
- Information Notice 2007-24, Summary of Fitness-for-Duty Program Performance Reports for Calendar Year 2006 (19 July 2007, Topic: Fitness for Duty, Contraband)
- Information Notice 2007-25, Recommendations From the Advisory Committee on the Medical Use of Isotopes for Improved Compliance with 10 CFR 35.40 and 35.27 (19 July 2007, Topic: Tritium Exit Sign)
- Information Notice 2007-25, Recommendations from the Advisory Committee on the Medical Use of Isotopes for Improved Compliance with 10 CFR 35.40 and 35.27 (19 July 2007, Topic: Enforcement Discretion)
- Information Notice 2007-26, E-mail from Alex Klein to Alex Marion Regarding NRC Information Notice 2007-26 (17 December 2007, Topic: Coatings)
- Information Notice 2007-27, Recurring Events and Trends Involving Emergency Diesel Generator Operability (6 August 2007, Topic: Preliminary White Finding)
- Information Notice 2007-28, Potential Common Cause Vulnerabilities in Essential Service Water Systems Due to Inadequate Chemistry Controls (19 September 2007, Topic: Probabilistic Risk Assessment, Frazil ice, Biofouling)
- Information Notice 2007-29, Temporary Scaffolding Affects Operability of Safety-Related Equipment (17 September 2007, Topic: High Energy Line Break, Fire Protection Program, Scaffolding)
- Information Notice 2007-30, Radiological Controls Create Criticality Safety Accident Scenario for Fissile Solution Container Transport at Fuel Cycle Facility (13 September 2007, Topic: Coatings, TheraSphere)
- Information Notice 2007-31, U.S. Food and Drug Administration Announcement Related to Sleep Disorder Drugs (13 November 2007, Topic: Fitness for Duty, Coatings, TheraSphere)
- Information Notice 2007-32, Out of Service Equipment Connected to in Service Process Line Results in Fissile Solution Spill at Fuel Cycle Facility (15 October 2007, Topic: Hydrostatic, Coatings, TheraSphere)
- Information Notice 2007-32, Out of Service Equipment Connected To In Service Process Line Results in Fissile Solution Spill at Fuel Cycle Facility (15 October 2007, Topic: Hydrostatic, Coatings, TheraSphere)
- Information Notice 2007-34, Operating Experience Regarding Electrical Circuit Breakers (22 October 2007)
- Information Notice 2007-36, Emergency Diesel Generator Voltage Regulator Problems (15 November 2007)
- Information Notice 2007-37, Buildup of Deposits in Steam Generators (23 November 2007)
- Information Notice 2007-38, Ensuring Complete and Accurate Information in the Documentation of Training and Experience for Individuals Seeking Medical Authorization Under the Alternate Pathway (14 December 2007, Topic: TheraSphere)
- Information Notice 2007-40, Inadequate Implementation of 10 CFR Part 21 Requirements by Vendors Who Supply Basic Components to Nuclear Power Plant Licensees (21 December 2007)
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