ML090300546 

UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

OFFICE OF NUCLEAR REACTOR REGULATION 

OFFICE OF NEW REACTORS 

WASHINGTON, DC 20555-0001 

July 21, 2009 

NRC INFORMATION NOTICE 2009-06: CONSTRUCTION-RELATED EXPERIENCE WITH 

FLOOD PROTECTION FEATURES 

ADDRESSEES 

All holders of operating licenses for nuclear power reactors and fuel cycle facilities, except those 

who have permanently ceased operations and have certified that fuel has been permanently 

removed from the reactor vessel; all current and potential applicants for an early site permit, 

combined license, or standard design certification for a nuclear power plant under the provisions 

of Title 10 of the Code of Federal Regulations (10 CFR) Part 52, “Licenses, Certifications, and 

Approvals for Nuclear Power Plants”; all current holders of and potential applicants for 

construction permits under 10 CFR Part 50, “Domestic Licensing of Production and Utilization 

Facilities.” 

PURPOSE 

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

addressees of construction-related operating experience involving inadequate flood protection 

features. The NRC expects recipients to review the information for applicability to their facilities 

and to 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 

Catawba Nuclear Station, Units 1 and 2 – Auxiliary Feedwater Pump Room Floor Drains 

On January 30, 2008, at the Catawba Nuclear Station, the licensee declared the Unit 1 and 

Unit 2 auxiliary feedwater (AFW) pumps inoperable. The reason for this declaration was that a 

licensee engineer discovered, contrary to plant drawings, that a total of nine flow restrictor 

plates (three for Unit 1 and six for Unit 2) were missing in the drains, of the interior steamline 

and feedline penetration rooms, that route water to the floor drain sumps located in the AFW 

pump room of each unit. It appeared that this deficiency of the missing flow restrictor plates 

dated back to initial construction of the plant. The drawings called for each floor drain to have a 

flow restrictor plate with a 1.588 centimeters (5/8-inch) orifice. Calculations indicated that, with 

all the flow restrictor plates installed, the flow would be limited so as not to exceed the capacity 

of the AFW sump pumps following a postulated main feedwater line break in one of two 

steamline and feedline penetration rooms per unit. This problem of the missing flow restrictor 

plates was only with the interior steamline and feedline penetration room per unit, not the 

exterior one. 
 IN 2009-06 

 Page 2 of 3 

The licensee also found that a historical calculation inappropriately assumed the following: (1) a 

non-conservative flood level and only two drains for each interior steamline and feedline 

penetration room, and (2) the availability of the floor drain sump pumps in each AFW pump 

room (which do not receive emergency power) to mitigate an event. Additional information is 

available in Catawba Licensee Event Report 50-413/2008-001, dated March 31, 2008, which 

can be found on the NRC’s public Web site in the Agencywide Documents Access and 

Management System (ADAMS), under Accession No. ML080940127. 

Nogent, Units 1 and 2, in France – Flooding Caused by a Large Leak in a Condenser 

Circulating Water Pipe 

On February 18, 2006, at the Nogent nuclear plant in France, a significant water leak in a 

pump’s discharge piping occurred in the Unit 2 condenser circulating water system (CWS), train 

1. The leak caused a pressure increase at the interface between the concrete foundation raft 

and the concrete floor in the Unit 2 turbine hall, and the turbine hall floor partly lifted about 10 to 

12 centimeters (3.9 to 4.7 inches) higher than the foundation raft. The lifting of the turbine floor 

caused a misalignment of the manhole inlet and rupture of nearly all the 1.6 centimeters (0.63 

inches) diameter floor-to-raft anchor rods distributed around the manhole inlet. Water flooded 

the Unit 2 turbine hall through the failed manhole, then flowed through a tunnel connecting the 

two units, and flooded the Unit 1 turbine hall. Both turbine halls were filled with water to a height 

of about 1 meter (3.28 feet). The water then spread from the tunnel between the units to the 

essential service water (ESW) system gallery through penetration sleeves. From the ESW 

gallery, the water entered the train A component cooling water pump room via a drain. The 

cause of the CWS manhole failure in Unit 2, train 1, was attributed to the specific construction of 

the manhole. In train 1, the manhole inlet and cover are bolted to the manhole’s steel shell 

which is anchored to the turbine hall floor rather than concrete foundation raft. Therefore, the 

water was able to penetrate the interface between the floor and the foundation raft. 

BACKGROUND 

Applicable Regulatory Documents:

1. Regulatory Guide 1.59, Revision 2, “Design Basis Floods for Nuclear Power Plants” 

(ADAMS Accession No. ML003740388), dated August 1977, describes how nuclear power 

plants should be designed to prevent the loss of capability for cold shutdown and 

maintenance thereof resulting from the most severe flood conditions that can be reasonably 

predicted to occur at a site as a result of severe hydro-meteorological conditions, seismic 

activity, or both. 

2. NUREG-1174, “Evaluation of Systems Interactions in Nuclear Power Plants," dated May 

1989, describes technical findings related to unresolved safety issue A-17. Generic Issue 

77, which was incorporated into the resolution of safety issue A-17, involved internal 

flooding in nuclear power plants. 
 IN 2009-06 

 Page 3 of 3 

3. NUREG-1055, “Improving Quality and the Assurance of Quality in the Design and 

Construction of Nuclear Power Plants” (ADAMS Accession No. ML063000293), dated May 

1984, alerts addresses to the lessons learned during the construction of nuclear plants in the 

United States. 

DISCUSSION 

The operating experience discussed in this IN involves deficiencies in flood protection features 

that originated during construction. Such problems often stem from the failure to adequately 

translate the plant design basis requirements into the initial design. General Design Criterion 2, 

“Design Bases for Protection Against Natural Phenomena,” of Appendix A to 10 CFR 50, 

provides plant design requirements regarding the ability to withstand the effects of natural 

phenomena such as floods. In addition, the above Catawba example illustrates the importance 

of developing and implementing an effective change process as required by 10 CFR 50, 

Appendix B, Criterion III, “Design Control,” during initial plant design and construction. 

CONTACT

This information notice requires no specific action or written response. Please direct any 

questions about this matter to the technical contacts listed below. 

/RA/ /RA/ 

Timothy J. McGinty, Director Glenn Tracy, Director 

Division of Policy and Rulemaking Division of Construction Inspection and 

Office of Nuclear Reactor Regulation Operational Programs 

 Office of New Reactors 

Technical Contacts: Omid Tabatabai, NRO/DCIP Edmund Kleeh, NRO/DCIP 

 (301) 415-6616 (301) 415-2964 

 omid.tabatabai@nrc.gov edmund.kleeh@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 2009-06 

Page 3 of 3 

3. NUREG-1055, “Improving Quality and the Assurance of Quality in the Design and 

Construction of Nuclear Power Plants” (ADAMS Accession No. ML063000293), dated May 

1984, alerts addresses to the lessons learned during the construction of nuclear plants in 

the United States. 

DISCUSSION 

The operating experience discussed in this IN involves deficiencies in flood protection features 

that originated during construction. Such problems often stem from the failure to adequately 

translate the plant design basis requirements into the initial design. General Design Criterion 2, 

“Design Bases for Protection Against Natural Phenomena,” of Appendix A to 10 CFR 50, 

provides plant design requirements regarding the ability to withstand the effects of natural 

phenomena such as floods. In addition, the above Catawba example illustrates the importance 

of developing and implementing an effective change process as required by 10 CFR 50, 

Appendix B, Criterion III, “Design Control,” during initial plant design and construction. 

CONTACT

This information notice requires no specific action or written response. Please direct any 

questions about this matter to the technical contacts listed below. 

/RA/ /RA/ 

Timothy J. McGinty, Director Glenn Tracy, Director 

Division of Policy and Rulemaking Division of Construction Inspection and 

Office of Nuclear Reactor Regulation Operational Programs 

 Office of New Reactors 

Technical Contacts: Omid Tabatabai, NRO/DCIP Edmund Kleeh, NRO/DCIP 

 (301) 415-6616 (301) 415-2964 

 omid.tabatabai@nrc.gov edmund.kleeh@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 

ADAMS Accession Number: ML090300546 TAC No. ME0470 

OFFICE CCIB:NRO TECH EDITOR TL:CCIB:NRO BC:CCIB:NRO BC:SBPB:NRR BC:OIP

NAME EKleeh KAzariah-Kribbs OTabatabai JStarefos DHarrison CAbrams 

DATE 02/04/09 03/03/09 02/04/09 02/06/09 02/20/09 03/12/09 

OFFICE PGCB:DPR PGCB:DPR BC:PGCB:DP D:DPR D:DCIP:NRO 

NAME DBeaulieu CHawes MMurphy TMcGinty GTracy 

DATE 03/24/09 03/25/09 07/15/2009 07/17/2009 07/21/2009 

OFFICIAL RECORD COPY