ML091240039 

UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

OFFICE OF NUCLEAR REACTOR REGULATION 

WASHINGTON, DC 20555-0001 

July 7, 2009 

NRC INFORMATION NOTICE 2009-11: CONFIGURATION CONTROL ERRORS 

ADDRESSEES

All holders of operating licensees for nuclear power reactors under the provisions of Title 10 of 

the Code of Federal Regulations (10 CFR) Part 50, “Domestic Licensing of Production and 

Utilization Facilities,” except those who have ceased operations and have certified that fuel has 

been permanently removed from the reactor vessel. All holders of and applicants for nuclear 

power plant construction permits under the provisions of 10 CFR Part 50. 

PURPOSE

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform 

addresses of recent configuration control errors, particularly those that occurred during an event 

at Prairie Island Unit 1 in which a turbine-driven auxiliary feedwater (AFW) pump was rendered 

inoperable by a mispositioned valve. 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

Prairie Island Nuclear Generating Plant Unit 1 – Loss of Turbine-Driven AFW Pump 

On July 31, 2008, following an inadvertent reactor trip of Prairie Island Unit 1, the turbine-driven 

AFW pump automatically started as designed but tripped 42 seconds later on low discharge 

pressure. The licensee found the turbine-driven AFW pump trip resulted from a mispositioned 

(closed) isolation valve for the discharge pressure switch. A time delay in the pump protective 

circuitry is designed to trip the pump when a continuing low discharge pressure condition exists. 

Monthly surveillances to test the operability of the turbine-driven AFW pump do not test the low 

discharge pressure trip function of the pump as the pump is tested in the manual operating 

mode, which bypasses the low discharge pressure trip. The licensee determined that sometime 

between March 11, 2008, and July 31, 2008, the isolation valve for the discharge pressure 

switch was closed rendering the turbine-driven AFW pump inoperable. 

The licensee determined that the cause for the improper isolation of the turbine-driven AFW 

pump discharge pressure switch was the failure to adequately control components that affect 

safety related equipment. Specifically: 

● The mispositioned valve was not labeled, bypassing barriers normally in place to assist 

in proper component identification. 
IN 2009-11 

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● The mispositioned valve was not locked in the required position, making mispositioning 

more likely. The procedure aligning the AFW system does not define which valves shall 

have locks, blocks or lock wires installed. 

● The procedure for component blocking or locking contains a definition of what 

components should not be controlled, but does not contain a definition of which 

components should be controlled. 

Licensee corrective actions for this event included the following: 

● Conduct a review to identify all other components that could affect operability of 

safety-related systems. Establish that each identified component is included in the 

equipment database and drawings, has a locking device installed, and is labeled in the 

field. 

● Lock-wired open the suction and discharge pressure switch manifold isolation valves for 

all four AFW pumps. 

● Revise the procedure for component locking and blocking. 

Additional information is available in Prairie Island Nuclear Generating Plant – NRC Special 

Inspection Report 05000282/2008008; 05000306/2008008, dated November 7, 2008, and can 

be found on the NRC’s public website in the Agencywide Documents Access and Management 

System (ADAMS) under Accession No. ML083120510. This event was also the subject of 

Prairie Island Licensee Event Report (LER) 50-282/2008-003, dated September 29, 2008 

(ADAMS Accession No. ML082730902). 

Other Recent Configuration Control Error Events

 

The NRC Operating Experience Branch reviewed recent mispositioning events that were the 

subject of NRC inspection findings and LERs. A listing and brief description of each of these 

NRC inspection findings and LERs is publically available in ADAMS under Accession No. 

ML091610448. 

The recent events show that component mispositionings have occurred or remained undetected 

due to one or more of the following causal factors: 

● Failure to use or establish administrative controls, including: proper component labeling, 

proper valve locking, use of valve checklists, work and testing procedures use of postmaintenance flow testing confirmation (when necessary) 

● Dependence on a single administrative control to prevent valve mispositioning events 

● Insufficient training (lack of refresher training) or experience in determination of valve 

position by individuals, (such as using rising stem position to help confirm valve position) 

● Improper independent verification or incorrect valve locking techniques 

● Lack of operator awareness of unique valve design or valve operating characteristics 

● Unrecognized operator burdens that increase the likelihood of error 

● Failure to effectively apply station and industry operating experience 
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Corrective actions taken by some licensees for preventing configuration control errors include: 

● Label components with a unique plant equipment number and name ensuring they are 

consistent with the designations used in plant procedures, drawings, and labels on the 

operating controls. 

● Provide initial and periodic refresher training of operators, maintenance, and supervisory 

personnel related to configuration control. 

● Use the corrective action program to track and trend configuration control errors. 

● Discuss site and industry operating experience and use operating experience feedback 

mechanisms. 

● As procedures are performed, identify incorrect procedural steps or improper valve 

labeling so that they can be corrected. 

BACKGROUND 

Previous NRC Generic Communications Involving Configuration Control

NRC IN 97-14, “Assessment of Spent Fuel Pool Cooling,” notes that ineffective configuration 

control was the most frequent cause of spent fuel pool loss-of-inventory events and loss of 

spent fuel pool cooling events. This IN is available under ADAMS Accession No. 

ML031050356. 

NRC IN 98-34, “Configuration Control Errors,” discusses configuration control errors involving 

the emergency diesel generator system noting that the potential exists for similar problems to 

occur in other systems. This IN is available under ADAMS Accession No. ML031050070. 

NRC IN 2007-11, “Recent Operator Performance Issues at Nuclear Power Plants,” provides 

examples of improper alignment of the AFW system and is available under ADAMS Accession 

No. ML070440238. 

DISCUSSION 

Configuration control errors, such as the mispositioning of valves or switches, can result in 

technical specification required systems being rendered inoperable and can complicate 

recovery actions following plant transients. Proper configuration control is particularly important 

for those single components that, if mispositioned, would render the system inoperable. From 

this group of important single components, proper configuration control is especially important 

when the mispositioned component would not be readily detected because (a) there is no alarm 

or other condition to alert the operators of the error, (b) the component is in a flow path that is 

not testable by surveillance procedures or (c) due to unique conditions the mispositioning may 

not be detected during routine surveillance testing. This example (c) was illustrated in the 

Prairie Island event where a mispositioned valve rendered an AFW system train inoperable and 

was not revealed during monthly surveillance testing. As a corrective action, the licensee 

established a configuration control measure to lock wire the valves in the correct position. 
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CONTACT

This IN requires no specific action or written response. Please direct any questions about this 

matter to the technical contact listed below or the appropriate Office of Nuclear Reactor 

Regulation (NRR) project manager. 

/RA/

Timothy J. McGinty, Director 

Division of Policy and Rulemaking 

Office of Nuclear Reactor Regulation 

Technical Contact: Mark King, NRR/DIRS 

301-415-1150 

E-mail: Mark.King@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. 
IN 2009-11 

Page 4 of 4 

CONTACT

This IN requires no specific action or written response. Please direct any questions about this 

matter to the technical contact listed below or the appropriate Office of Nuclear Reactor 

Regulation (NRR) project manager. 

/RA/

Timothy J. McGinty, Director 

Division of Policy and Rulemaking 

Office of Nuclear Reactor Regulation 

Technical Contact: Mark King, NRR/DIRS 

301-415-1150 

E-mail: Mark.King@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 r/f 

ADAMS Accession Number: ML091700188 TAC ME0460 

OFFICE IOEB TECH EDITOR IOEB BC:SBPB:DSS ABC:IOEB:DIRS D:DIRS

NAME MKing KAzariah-Kribbs LFields SGardocki EThomas FBrown 

DATE 06/10/09 06/11/09 e-mail 06/11/09 06/11/09 06/11/09 06/22/09 

OFFICE PGCB:DPR PGCB:DPR BC:PGCB:DPR D:DPR

NAME DBeaulieu CHawes MMurphy TMcGinty 

DATE 06/19/09 06/22/09 07/01/09 07/07/09 

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