Information Notice 2009-06, Construction-Related Experience with Flood Protection Features
| ML090300546 | |
| Person / Time | |
|---|---|
| Issue date: | 07/21/2009 |
| From: | Edmund Kleeh NRC/NRO/DCIP/CCIB |
| To: | |
| Kleeh E, NRO/DCIP/CCIB, 415-2964 | |
| References | |
| IN-09-006 | |
| Download: ML090300546 (4) | |
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.
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 NRCs 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
pumps 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 manholes 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. 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
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