Information Notice 1989-80, Potential for Water Hammer, Thermal Strafication, and Steam Binding in High-Pressure Coolant Injection Piping
UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555December 1, 1989NRC INFORMATION NOTICE NO. 89-80: POTENTIAL FOR WATER HAMMER, THERMALSTRATIFICATION, AND STEAM BINDINGIN HIGH-PRESSURE COOLANT INJECTIONPIPING
Addressees
- All holders of operating licenses or construction permits for nuclear powerreactors.
Purpose
- This information notice is being provided to alert addressees to potential pro-blems resulting from failure of high-pressure coolant injection((HPCI) valvesin a boiling-water reactor (BWR) to prevent leakage of feedwater into the HPCIsystem during operation of the reactor at power. It is expected that recipientswill review the information for applicability to their facilities and consideractions, as appropriate, to avoid similar problems. However, suggestions con-tained in this information notice do not constitute NRC requirements; therefore,no specific action or written response is required.
Description of Circumstances
- On February 21, 1989, with Dresden Unit 2 operating at power, temperature wasgreater than normal in the HPCI pump and turbine room. The abnormal heat loadwas caused by feedwater leaking through uninsulated HPCI piping to the condensatestorage tank. During power operation, feedwater temperature is less than 3500F,and feedwater pressure is approximately 1025 psi. Normally, leakage to the con-densate storage tank is prevented by the injection check valve; the injectionvalve, or the discharge valve on the auxiliary cooling water pump. The injectionvalve and the injection check.valve are shown in Attachment 1.On October 23, 1989, with the reactor at power, leakage had increased suffi-ciently to raise the temperature between the injection valve and the HPCIpump discharge valve to 2750F and at the discharge of the HPCI pump to 2460F.Pressure in the HPCI piping was 47 psia. On the basis of the temperaturegradient and the pressure in the piping, the licensee concluded that feedwaterleaking through the injection valve was flashing and displacing some of thewater in the piping with steam. This conclusion was confirmed by closing thepump discharge valve and monitoring the temperature of the piping. As expected,the pipe temperature decreased to ambient.:891127000o j, @
IN 89-80December 1, 1989 Accessible portions of the HPCI piping were inspected, and some loose pipesupports were found near the injection valves. Concrete surfaces near thesupport attachment points were spalled.The licensee declared the HPCI system inoperable on October 23, 1989, andnotified NRC pursuant to 10 CFR 50.72. After performing a review under 10CFR 50.59, the licensee opened the normally closed injection valve, closedthe normally open discharge valve, and will use the discharge valve temporarilyas the injection valve.Temperature measurements on the HPCI piping at Dresden Unit 3 indicated thatless significant leakage was occurring.Discussion:The event at Dresden is significant because the potential existed for waterhammer or thermal stratification to cause failure of the HPCI piping and forsteam binding to cause failure of the HPCI pump. Further, failure of HPCIpiping downstream from the injection valves would cause loss of one of twofeedwater pipes.The licensee has not heard the noise that is usually associated with waterhammers. Nevertheless, loosening of the pipe supports, damage to concretesurfaces, and the presence of steam in the piping strongly Indicate thatwater hammers had occurred in the HPCI system, probably during HPCI pumptests or valve manipulations. Temperature-monitoring instrumentation onthe piping near the injection valves was useful in detecting the leak. NRCInformation Notices 85-76, 86-01, 87-10, and 88-13 all address water hammerevents at other facilities. Attachment 2 lists these and other referencesmentioned in this notice.Concern for potential thermal stratification in the HPCI piping is relatedto three events in pressurized-water reactors (PWRs) that were the basis forissuing NRC Bulletin 88-08 and the three supplements to that bulletin. Theseevents occurred in one of the Farley units and in two foreign reactors. Inall of the events, water leaked either from or to the reactor coolant systemthrough closed valves in an emergency coolant system. Thermal stratificationof water in the piping of the emergency coolant system and fluctuations ofthe interface between the hot and cold streams of water resulted in thermalfatigue and cracking of the piping wall in the heat-affected zones of weldsand in the base metal. For these reactors, the configuration of the pipingbetween the reactor coolant system and the first valve in the emergency coolingsystem is approximately like the configuration of the piping at Dresden. Thelicensee for Dresden does intend to examine the piping ultrasonically at thenext scheduled outage to determine whether detectable damage has occurred.During the event at Dresden, the potential for steam bindingv the HPCI pumpexisted because the discharge valve was normally open. Events have occurredin PWRs that have resulted in steam binding of auxiliary feedwater pumps.Because the NRC staff was concerned about the availability of the auxiliary -$ '
'4,IN 89-80December 1, 1988 feedwater pumps when needed to mitigate the consequences of an accident, thestaff Issued NRC Bulletin 85-01. The bulletin required that certain licenseesdevelop Procedures for monitoring the temperature of the pump discharge toensure that it remains at less than saturation temperature and to identifysteam binding and restore the operability of the system if it occurs.The NRC may issue additional information as more inspection and analysis iscompleted.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate NRR projectmanager. I* e4Charles E. Rossi, DrecDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts: Eric W. Weiss, AEOD(301) 492-9005Roger Woodruff, NRR(301) 492-1180Attachments:1. Dresden 2 -High-Pressure Coolant Injection Line2. Referenced Generic Communications3. List of Recently Issued NRC Information NoticesI
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Attachment 2IN 89-80December 1, 1989 REFERENCED GENERIC COMMUNICATIONS1. NRC Information Notice No. 85-76, "Recent Water Hammer Events,"September 19, 1985.2. NRC Information Notice No. 86-01, "Failure of Main Feedwater Check ValvesCauses Loss of Feedwater System Integrity and Water Hammer Damage,"January 1, 1986.3. NRC Information Notice No. 87-10, "Potential for Water Hammer DuringRestart of Residual Heat Removal Pumps," February 2, 1987.4. NRC Information Notice No. 88-13, "Water Hammer and Possible Piping DamageCaused by Misapplication of Kerotest Packless Metal Diaphragm Globe Valves,"April 18, 1988.5. NRC Bulletin 85-01, "Steam Binding of Auxiliary Feedwater Pumps,"October 29, 1985.6. NRC Bulletin No. 88-08, "Thermal Stresses in Piping Connected to ReactorCoolant Systems," June 22, 1988; Supplement 1, June 24, 1988; Supplement 2,August 4, 1988; and Supplement 3, April.11, 1988.
Attachment 3IN 89-80December 1, 1989 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to89-7989-56,Supp. 189-78.89-77Degraded Coatings andCorrosion of SteelContainment VesselsQuestionable Certificationof Material Supplied tothe Defense Departmentby Nuclear SuppliersFailure of Packing Nutson One-Inch UraniumHexafluoride CylinderValvesDebris in ContainmentEmergency Sumps andIncorrect ScreenConfigurationsBiofouling Agent: ZebraMusselFalsification of WelderQualifications forContractor EmployeesClarification of Trans-portation RequirementsApplicable to Return ofSpent Radiopharmacy Dosagesfrom Users to SuppliersPotential Overpressurizationof Low Pressure Systems12/1/8911/22/8911/22/8911/21/8911/21/8911/20/8911/7/8911/1/89All holders of OLsor CPs for LWRs.All holders of OLsor CPs for nuclearpower reactors.All NRC licenseesauthorized to possessand use source materialand/or special nuclearmaterial for the heating,emptying, filling, orshipping of uraniumhexafluoride in 30-and 48-inch diametercylinders.All holders of OLsor CPs for PWRs.All holders of OLsor CPs for nuclearpower reactors.All holders of OLsor CPs for nuclearpower reactors.All manufacturersand distributors ofradiopharmaceuticalsfor medical use,nuclear pharmacies,and medical licensees.All holders of OLsor CPs for nuclearpower reactors.89-7689-7589-7489-73OL = Operating LicenseCP = Construction Permit
IN 89-80December 1, 1988 feedwater pumps when needed to mitigate the consequences of an accident, thestaff issued NRC Bulletin 85-01. The bulletin required that certain licenseesdevelop procedures for monitoring the temperature of the pump discharge toensure that it remains at less than saturation temperature and to identifysteam binding and restore the operability of the system if it occurs.The NRC may issue additional information as more inspection and analysis iscompleted.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate NRR projectmanager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:Eric W. Weiss, AEOD(301) 492-9005Roger(301)Woodruff, NRR492-1180Attachments:1. Dresden 2 -High-Pressure Coolant Injection Line2. Referenced Generic Communications3. List of Recently Issued NRC Information Notices*SEE PREVIOUS CONCURRENCEEAB: NRR*RWoodruff:db11/12/89C:PB1:RIII*WShafer11/13/89IRB:AEOD*EWeiss11/14/89C:EAB:NRR*CHaughney11/15/89TECH EDITOR*RSanders11/15/89C:OGCB:NRR*CBerlinger11/22/89EAB:NRR*PBaranowsky11/1§/89D:06A.CERossi DO11/;1/89PM:PD32:NRR*BSiegel11/15/89 INRCIN 88-xxNovember x, 1988 monitoring the temperature of the pump discharge to ensure that it is at lessthan saturation temperature and to identify steam binding if it occurs.The NRC may issue additional information as more inspection and analysis iscompleted.No specific action or written response is required by this informationnotice. If you have questions about this matter, please call one of thetechnical contacts listed below or the Regional Administrator of theappropriate regional office.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:Eric W. Weiss, AEOD(301) 492-9005Roger Woodruff, NRR(301) 492-1180Attachments:1. Dresden 2 -High-Pressure Coolant Injection Line2. List of Recently Issued Information Notices*SEE PREVIOUSEAB:NRR*RWoodruff:db11/ /89C:PB1:RIII*WShafer11/ /89CONCURRENCEIRB:AEOD*EWeiss11/ /L6TECH EDITOREAB:NRRPBaranomsky11/1 5/89PM:PD32:NRRBSiegelrP11115189 KoD:DOEA:NRRCERossi11/ /891 /WY/89Doc: 299A
4.1.dNRCIN 88-xxNovember x, 1988 temperature of the pump discharge to assure that it is at less thansaturation temperature and to identify steam binding if it occurs.The NRC may issue additional information as more inspection and analysis iscompleted.No specific action or written response is required by this informationnotice. If you have questions about this matter, please call one of thetechnical contacts listed below or the Regional Administrator of theappropriate regional office.Charles E. Rossi. DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:Eric W. Weiss, AEOD(301) 492-9005Roger Woodruff, NRR(301) 492-1180Attachments:1. Dresden 2 -High Pressure Coolant Injection Line2. List of Recently Issued Information NoticesEAB:NRRRWoodruff:db11/111893BM tricpkoa~C:PB1:RILI~WShafer-Cd,'11/13/89IRB:AEODEWei S11/1 /89C:EAB:NRRCHaughney11/ /89TECH EDITOR11/1ST/89C:OGCB:NRRCBerlinger11/ /89EAB:NRRPBaranowsky11/ /89PM:PD32:NRRBSiegel11/ /89D:DOEA:NRRCERossi11/ /89