UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, DC 20555-0001

September 17, 2007

NRC INFORMATION NOTICE 2007-29: TEMPORARY SCAFFOLDING AFFECTS

OPERABILITY OF SAFETY-RELATED

EQUIPMENT

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 alert

licensees about recent operating experience at nuclear power facilities where temporary

scaffolding installed to support maintenance activity has affected the operability of safetyrelated equipment. 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.

DESCRIPTION OF CIRCUMSTANCES

Several recent events have occurred at nuclear power facilities where temporary scaffolding

that has affected the operability of safety-related equipment. Specific instances include the

following:

Millstone Power Station Unit 2

Scaffolding was constructed adjacent to a main steam isolation valve (MSIV) to support

replacing the operating cylinder during the upcoming refueling outage. Supplementary

instructions were provided for building the scaffolding close to safety-related equipment, and a

post-installation inspection was performed. Approximately forty days later during a MSIV stroke

time test, the MSIV was determined to be inoperable due to scaffold decking interfering with the

travel of the valve actuator preventing the MSIV from fully closing. 

Also at Millstone Unit 2, temporary scaffolding was inadvertently placed on top of a blowout

panel in the turbine-driven auxiliary feedwater pump room ceiling. The impact of this oversight

could have resulted in all three auxiliary feedwater pumps becoming inoperable during 

ML072150614
IN 2007-29

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a high energy line break. (NRC Integrated Inspection Report 05000336/2006005 and

05000423/2006005, January 30, 2007, Agencywide Documents Access and Management

System (ADAMS) Accession No. ML070300143)

Beaver Valley Power Station Unit 2

The licensee discovered that scaffolding constructed around the ‘A’ and ‘B’ MSIVs two days

earlier had seismic bracing located in the path of MSIV travel. This condition could have

potentially prevented the MSIVs from fully closing. (NRC Integrated Inspection Report

05000334/2006005 and 05000412/2006005, January 24, 2007, ADAMS Accession No.

ML070260053)

Oyster Creek Generating Station

NRC inspectors identified a scaffold pole in contact with piping associated with the scram

discharge volume. This condition was not consistent with the licensee’s scaffold procedure

which states that scaffold shall not be in contact with safety-related piping. During the

subsequent disassembly of this scaffolding, a scaffold coupler (“knuckle”) fell and damaged an

oiler reservoir for the ‘B’ core spray booster pump, rendering the pump inoperable for

approximately twelve hours to effect repair. (NRC Integrated Inspection Report

05000219/2006003, July 13, 2006, ADAMS Accession No. ML061950007) 

Monticello Nuclear Generating Plant

NRC inspectors identified a scaffold that was in contact with safety-related piping for the

residual heat removal system. This condition was not consistent with the licensee’s scaffolding

procedure that specifies maintaining a clearance of greater than 2 inches from safety-related

equipment. During the extent of condition review, the licensee found two scaffolds erected in

the intake structure that were less than 2 inches away from fire protection piping. The licensee

determined that all three scaffolds were originally constructed with the required 2-inch

separation, but the separation became less than 2 inches during use of the scaffolds. The

Licensee revised their scaffold control procedure to provide additional guidance on the need for

adequate bracing to prevent scaffolding from moving during use. (NRC Integrated Inspection

Report 05000263/2006002, April 26, 2006, ADAMS Accession No. ML061160574)

Turkey Point Nuclear Plant

NRC inspectors identified two examples where scaffolding was not installed in accordance with

scaffold control procedures. The licensee requires that installed scaffolding be a minimum of 2

inches from fragile items, including but not limited to valves and instrument lines. The first

example involved scaffolding erected within 2 inches of the Unit 3 refueling water storage tank

suction valves. The second example involved scaffolding that was in contact with an

emergency diesel generator starting air system pipe hanger. The licensee’s corrective actions

included revising their scaffolding procedure to establish a minimum clearance requirement of 2

inches for all plant equipment and to emphasize the requirement to perform an engineering

evaluation when the procedural requirements could not be met. (NRC Problem Identification

and Resolution Inspection Report 050000250/2006007 and 05000251/2006007, March 17,

2006, ADAMS Accession No. ML060760175)
IN 2007-29

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BACKGROUND

Systems and components that are required to be operable by technical specifications or by the

fire protection program can be rendered inoperable by improperly installed scaffolding. 

Technical specification administrative requirements and Title 10 of the Code of Federal

Regulations (10 CFR) Part 50, Appendix B, Criterion V, “Instructions, Procedures and

Drawings,” require procedural controls for certain activities that would include scaffolding

controls. 

In addition, NRC Regulatory Guide 1.187, “Guidance for Implementation of 10 CFR 50.59,

Changes, Tests, and Experiments,” endorses the Nuclear Energy Institute (NEI) document NEI

96-07, “Guidelines for 10 CFR 50.59 Evaluations,” Revision 1. NEI 96-07 states that: 

temporary changes to the facility such as the installation of scaffolding that are not associated

with maintenance are subject to 10 CFR 50.59 in the same manner as permanent changes, to

determine if prior NRC approval is required; the risk impacts of temporary changes associated

with maintenance activities (i.e., temporary alterations) should be assessed and managed in

accordance with 10 CFR 50.65(a)(4), and associated guidance; and applying 10 CFR 50.59 to

such activities is not required provided that temporary alterations are not in effect longer than

90 days at power, and affected structure, system or components are restored to their normal,

as-designed condition at the conclusion of the maintenance activity. 

DISCUSSION

The above events highlight the need to adequately establish and implement procedural controls

so that scaffolding does not adversely affect safety-related equipment. It is important that

scaffolding: does not interfere with the operation of equipment such as valves and ventilation

dampers; is properly braced to prevent displacement or sliding during use or during a seismic

event; is not directly attached to instrument racks or piping supports; does not block access to

fire protection equipment such as hose reels, fire extinguishers, and fire doors; and materials

that are non-fire retardant are accounted for as transient combustibles. At some facilities,

structures such as floor grating and scaffolding are required to be maintained greater than

some minimum distance from the containment wall to ensure that the integrity of the

containment is maintained during a design basis or seismic event.
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CONTACT

This information notice does not require any specific action or written response. Please direct

any questions about this matter to the technical contacts listed below or to 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: Stephen Pannier, NRR Heather Jones, Region I

(301) 415-4083 (610) 337-5390

E-mail: sjp@nrc.gov E-mail: hmj@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 2007-29

Page 4 of 4

CONTACT

This information notice does not require any specific action or written response. Please direct

any questions about this matter to the technical contacts listed below or to 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: Stephen Pannier, NRR Heather Jones, Region I

(301) 415-4083 (610) 337-5390

E-mail: sjp@nrc.gov E-mail: hmj@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 Number: ML072150614

OFFICE IOEB:DIRS IOEB:DIRS TECH EDITOR TL:IOEB:DIRS BC:IOEB:DIRS

NAME HJones SPannier LCulp by email JThorp MRoss-Lee

DATE 8/17/2007 8/27/2007 8/10/2007 8/24/2007 8/28/2007

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

NAME FBrown CHawes DBeaulieu MMurphy MCase

DATE 8/29/07 09/12/07 09/12/07 09/17/07 09/17/07

OFFICIAL RECORD COPY