Information Notice 2002-18, Effect of Adding Gas Into Water Storage Tanks on the Net Positive Suction Head for Pumps
| ML021570158 | |
| Person / Time | |
|---|---|
| Issue date: | 06/06/2002 |
| From: | Beckner W NRC/NRR/DRIP/RORP |
| To: | |
| Jung I, NRR/DRIP, 415-1837 | |
| References | |
| TAC M3971 IN-02-018 | |
| Download: ML021570158 (5) | |
UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, DC 20555-0001June 6, 2002NRC INFORMATION NOTICE 2002-018:EFFECT OF ADDING GAS INTO WATERSTORAGE TANKS ON THE NET POSITIVE
SUCTION HEAD FOR PUMPS
Addressees
All holders of operating licenses for nuclear power reactors, except those who havepermanently ceased operations and have certified that fuel has been permanently removed
from the reactor.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alertaddressees to the potential impact of adding gas into water storage tanks on the available net
positive suction head (NPSH) for pumps. The NRC anticipates that recipients will review this
information for applicability to their facilities and consider taking appropriate actions. However, the suggestions contained in this information notice do not constitute NRC requirements and, therefore, no specific action or written response is required.
Description of Circumstances
The NRC recently performed an inspection at the Union Electric Company's Callaway nuclearpower plant in response to the identification of a degraded condensate storage tank (CST)
floating diaphragm seal. The degradation resulted in a failure of a motor-driven auxiliary
feedwater (AFW) pump. It also had the potential to induce a common-cause failure of multiple
AFW pumps. The inspection included a review of several calculations related to the available
NPSH for AFW pumps. The NRC inspection report may be found in the NRC Agency
Document and Management System (ADAMS) under Accession Number ML 020810177.Prior to 1988, the Callaway nuclear power plant controlled the amount of dissolved oxygen inthe CST water by recirculating water to the main condenser hotwell. However, the licensee
determined that this method of removing oxygen from the CST caused water temperatures to
exceed the allowable water temperature for the AFW system during the summer months. To
prevent high water temperatures, the licensee modified the design to add a nitrogen sparging
system to the CST.The NRC found that the licensee's previous calculations did not appropriately address the effectof the nitrogen-saturated water on the available NPSH for the AFW pumps. The licensee's
recent NPSH calculation included the effect of nitrogen addition to the CST. The revised
calculation indicated that the available NPSH was reduced by approximately 11 feet for the
A-train motor-driven AFW pump. ML021570158 IN 2002-018
DISCUSSION
This example at the Callaway nuclear power plant shows that the available NPSH for the AFWpumps was significantly reduced when nitrogen gas is added to the CST to control dissolved
oxygen. Criterion III, "Design Control," in Appendix B to Title 10, Part 50 of the Code of FederalRegulations (10 CFR Part 50) requires, in part, that each licensee must implement designcontrol measures to verify or check the adequacy of design through the use of alternate or
simplified calculational methods, or by performing a suitable testing program. In general, it is
important to consider the effect on available NPSH for pumps when modifying the pumps
'suction source (e.g., CST and Refueling Water Storage Tank). Inadequate NPSH can result in
significantly degraded pump performance or pump failure.This information notice does not require any specific action or written response. If you haveany questions about the information in this notice, please contact the technical contacts listed
below or the appropriate project manager from the NRC
's Office of Nuclear Reactor Regulation. /RA/William D. Beckner, Program Director
Operating Reactor Improvements Program
Division of Regulatory Improvement Programs
Office of Nuclear Reactor RegulationTechnical contact:Ian Jung, NRRTroy Pruett, Region IV(301) 415-1837(817) 860-8182 Email: ixj@nrc.govEmail: twp@nrc.govAttachment: List of Recently Issued NRC Information Notices
DISCUSSION
This example at the Callaway nuclear power plant shows that the available NPSH for the AFWpumps was significantly reduced when nitrogen gas is added to the CST to control dissolved
oxygen. Criterion III, "Design Control," in Appendix B to Title 10, Part 50 of the Code of FederalRegulations (10 CFR Part 50) requires, in part, that each licensee must implement designcontrol measures to verify or check the adequacy of design through the use of alternate or
simplified calculational methods, or by performing a suitable testing program. In general, it is
important to consider the effect on available NPSH for pumps when modifying the pumps
'suction source (e.g., CST and Refueling Water Storage Tank). Inadequate NPSH can result in
significantly degraded pump performance or pump failure.This information notice does not require any specific action or written response. If you haveany questions about the information in this notice, please contact the technical contacts listed
below or the appropriate project manager from the NRC
's Office of Nuclear Reactor Regulation. /RA/William D. Beckner, Program Director
Operating Reactor Improvements Program
Division of Regulatory Improvement Programs
Office of Nuclear Reactor RegulationTechnical contact:Ian Jung, NRRTroy Pruett, Region IV(301) 415-1837(817) 860-8182 Email: ixj@nrc.govEmail: twp@nrc.govAttachment: List of Recently Issued NRC Information NoticesDISTRIBUTION
- PUBLIC
IN Reading FileADAMS ACCESSION NO.:Template: NRR-052DOCUMENT NAME: G:RORP\OES\JUNG\INCALLAWAY-NPSH.WPD*See previous concurrenceOFFICERSE:RORP:DRIPTECH EDITORSC:EMEB:DESC:SPLB:DSSASC:RORP:DRIPPD:RORP:DRIPNAMEICJungPAGarrity*DTeraoSWeerakkodyTReisWDBecknerDATE05/ /200205/ 10 /200205/21/200205/21/200205/09200206/06/2002OFFICIAL RECORD COPY
______________________________________________________________________________________OL = Operating License
CP = Construction PermitAttachment 1IN 2002-018 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICES
_____________________________________________________________________________________InformationDate of
Notice No. SubjectIssuanceIssued to
_____________________________________________________________________________________2002-16Intravascular BrachytherapyMisadministrations05/01/2002All Medical Licensees.2002-15Hydrogen Combustion Eventsin Foreign BWR Piping04/12/2002All holders of operating licensesfor light water reactors, except
those who have permanently
ceased operations and have
certified that fuel has been
permanently removed from the
reactor.2002-14Ensuring a Capability toEvacuate Individuals, Including
Members of the Public, From
the Owner-Controlled Area04/08/2002All holders of operating licensesfor nuclear power reactors, including those who have ceased
operations but have fuel on site.2002-13Possible Indicators of OngoingReactor Pressure Vessel Head
Degradation04/04/2002All holders of operating licensesfor pressurized water nuclear
power reactors, except those who
have permanently ceased
operations and certified that fuel
has been permanently removed
from the reactor.99-28, Supp 1Recall of Star Brand FireProtection Sprinkler Heads03/22/2002All holders of licenses for nuclearpower, research, and test
reactors and fuel cycle facilities.2002-12Submerged Safety-RelatedElectrical Cables03/21/2002All holders of operating licensesor construction permits for
nuclear power reactorsNote:NRC generic communications may be received in electronic format shortly after they are issued bysubscribing to the NRC listserver as follows:To subscribe send an e-mail to <listproc@nrc.gov >, no subject, and the following command in themessage portion:subscribe gc-nrr firstname lastname