UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, DC 20555-0001
March 26, 2007
NRC INFORMATION NOTICE 2007-09:
EQUIPMENT OPERABILITY UNDER DEGRADED
VOLTAGE CONDITIONS
ADDRESSEES
All holders of operating licensees 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 an event in which safety-related pump motors did not have adequate voltage at
the starter circuit to ensure operability under degraded voltage conditions and a related
deficiency involving a surveillance test procedure that specified an incorrect value for the
emergency diesel generator (EDG) minimum acceptable voltage. NRC staff expects 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 August 17, 2006, the licensee for the Fermi 2 nuclear power plant declared all four EDGs
inoperable due to undersized control power transformers for each of the EDG service water
pumps. The concern was that the EDG service water pump motors did not have adequate
voltage at the starter circuit to ensure operability under degraded voltage conditions. The event
was caused by a design error that occurred in 1998 when a design change was prepared for
the replacement of motor control center buckets that did not account for the fact that the higher
inrush current of replacement contactors would necessitate installation of a larger control power
transformer. As part of the extent of condition review, the licensee also identified similar
concerns with the Division 1 EDG room ventilation fans. Subsequent analysis further revealed
a lack of a voltage margin on other potentially risk-significant components. The licensee
submitted a licensee event report (LER) to describe the event (LER 50-341/2006-004-00,
Agencywide Documents Access and Management System (ADAMS) Accession No.
ML0629302170).
During a special inspection of the above event, the NRC inspectors identified that the Division 1 EDG surveillance test procedure specified minimum required EDG voltage of 3740 volts which
was below the calculated minimum voltage required for component operability. As a result, the
surveillance test would not ensure that the Division 1 EDGs would support the operability of the
required components. To correct this deficiency, Fermi nuclear power plant established
administrative controls, pending procedure and technical specifications revision, to ensure that
future testing of the Division 1 EDGs would include a minimum required voltage acceptance
criterion of 3873 volts. (NRC Special Inspection Report 05000341/2006015, dated
November 7, 2006, ADAMS Accession No. ML0631204130).
BACKGROUND
Branch Technical Position PSB-1 of the Standard Review Plan (NUREG-0800) recommends
that the second level of undervoltage (degraded voltage) protection should be based on an
analysis of the voltage requirements of the Class 1E loads at all onsite system distribution
levels. The voltage levels at the safety-related busses should be optimized for the maximum
and minimum load conditions that are expected throughout the anticipated range of voltage
variations of the offsite power sources. Consequently, when powering the safety-related
busses from EDGs, the minimum required EDG steady state voltage must be greater than or
equal to the minimum established voltage for component operability.
DISCUSSION
It is important that EDG surveillance procedures specify a minimum EDG steady state voltage
that is greater than or equal to the calculated bus minimum voltage required for component
operability.
CONTACT
This IN requires no specific action or written response. Please direct any questions about this
matter to one of 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:
Amar Pal, NRR/DE
301-415-2760
E-mail: anp@nrc.gov
Omid Tabatabai, NRR/DIRS
301-415-6616 E-mail: oty@nrc.gov
Note: NRC generic communications may be found on the NRC public Website, http://www.nrc.gov, under Electronic Reading Room/Document Collections.
CONTACT
This IN requires no specific action or written response. Please direct any questions about this
matter to one of 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:
Amar Pal, NRR/DE
301-415-2760
E-mail: anp@nrc.gov
Omid Tabatabai, NRR/DIRS
301-415-6616 E-mail: oty@nrc.gov
Note: NRC generic communications may be found on the NRC public Website, http://www.nrc.gov, under Electronic Reading Room/Document Collections.
DISTRIBUTION:
IN FILE
ADAMS Accession Number: ML070390066 OFFICE
EEEB:DE
Tech Editor
BC:EEEB:DE:
IOEB:DIRS
TL:IOEB:DIRS:
NAME
APal
CClark
IJung
OTabatabai
JThorp
DATE
2/09/2007
2/07/2007
2/09/2007
2/08/2007
2/13/2007 OFFICE
PGCB:DPR
PGCB:DPR
BC:PGCB:DPR
D:PGCB
NAME
CHawes CMH
DBeaulieu
CJackson
TQuay for MCase
DATE
2/26/2007
3/6 /2007
3 /23/2007
3/26/2007 OFFICIAL RECORD COPY
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| list | - Information Notice 2007-01, Recent Operating Experience Concerning Hydrostatic Barriers (31 January 2007, Topic: Hydrostatic)
- Information Notice 2007-02, Recent Operating Experience with Failure of the Male Coupling of the Lead Screw on the Control Rod Drive Mechanism (7 March 2007)
- 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, Microbiologically influenced corrosion, 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 2007-16, Common Violations of the Increased Controls Requirements and Related Guidance Documents (2 May 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: Foreign Material Exclusion)
- 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 2007-19, Fire Protection Equipment Recalls and Counterfeit Notices (21 May 2007)
- Information Notice 2007-20, Use of Blank Ammunition (11 June 2007)
- Information Notice 2007-21, Flow-induced Vibration Could Cause Reflective Metal Insulation to Damage Nuclear Power Plant Piping (11 June 2007, Topic: VT-2, Through-Wall Leak)
- 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, 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, 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: Enforcement Discretion)
- 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 2007-26, 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: Notice of Violation, 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 2007-33, Exposure to Members of the Public Caused by Inadequate Controls Over Well Logging Sources (28 September 2007, Topic: Coatings, TheraSphere)
- Information Notice 2007-34, Operating Experience Regarding Electrical Circuit Breakers (22 October 2007, Topic: Hardened grease)
- Information Notice 2007-35, Varian Medical Systems Varisource HDR Events: Iridium-192 Source Pulled from Shielded Position (17 October 2007, Topic: Coatings, TheraSphere)
- 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, Topic: Eddy Current Test)
- 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, Topic: Basic Component)
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