Information Notice 1989-80, Potential for Water Hammer, Thermal Strafication, and Steam Binding in High-Pressure Coolant Injection Piping
UNITED STATES NUCLEAR REGULATORY
COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 December 1, 1989 NRC INFORMATION
NOTICE NO. 89-80: POTENTIAL
FOR WATER HAMMER, THERMAL STRATIFICATION, AND STEAM BINDING IN HIGH-PRESSURE
COOLANT INJECTION PIPING
Addressees
All holders of operating
licenses or construction
permits for nuclear power reactors.
Purpose
- This information
notice is being provided to alert addressees
to potential
pro-blems resulting
from failure of high-pressure
coolant injection((HPCI)
valves in a boiling-water
reactor (BWR) to prevent leakage of feedwater
into the HPCI system during operation
of the reactor at power. It is expected that recipients
will review the information
for applicability
to their facilities
and consider actions, 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
was greater than normal in the HPCI pump and turbine room. The abnormal heat load was caused by feedwater
leaking through uninsulated
HPCI piping to the condensate
storage tank. During power operation, feedwater
temperature
is less than 350 0 F, and feedwater
pressure is approximately
1025 psi. Normally, leakage to the con-densate storage tank is prevented
by the injection
check valve; the injection valve, or the discharge
valve on the auxiliary
cooling water pump. The injection valve 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 HPCI pump discharge
valve to 275 0 F and at the discharge
of the HPCI pump to 246 0 F.Pressure in the HPCI piping was 47 psia. On the basis of the temperature
gradient and the pressure in the piping, the licensee concluded
that feedwater leaking through the injection
valve was flashing and displacing
some of the water in the piping with steam. This conclusion
was confirmed
by closing the pump discharge
valve and monitoring
the temperature
of the piping. As expected, the pipe temperature
decreased
to ambient.:891127000
o j, @
IN 89-80 December 1, 1989 Accessible
portions of the HPCI piping were inspected, and some loose pipe supports were found near the injection
valves. Concrete surfaces near the support attachment
points were spalled.The licensee declared the HPCI system inoperable
on October 23, 1989, and notified NRC pursuant to 10 CFR 50.72. After performing
a review under 10 CFR 50.59, the licensee opened the normally closed injection
valve, closed the normally open discharge
valve, and will use the discharge
valve temporarily
as the injection
valve.Temperature
measurements
on the HPCI piping at Dresden Unit 3 indicated
that less significant
leakage was occurring.
Discussion:
The event at Dresden is significant
because the potential
existed for water hammer or thermal stratification
to cause failure of the HPCI piping and for steam binding to cause failure of the HPCI pump. Further, failure of HPCI piping downstream
from the injection
valves would cause loss of one of two feedwater
pipes.The licensee has not heard the noise that is usually associated
with water hammers. Nevertheless, loosening
of the pipe supports, damage to concrete surfaces, and the presence of steam in the piping strongly Indicate that water hammers had occurred in the HPCI system, probably during HPCI pump tests or valve manipulations.
Temperature-monitoring
instrumentation
on the piping near the injection
valves was useful in detecting
the leak. NRC Information
Notices 85-76, 86-01, 87-10, and 88-13 all address water hammer events at other facilities.
Attachment
2 lists these and other references
mentioned
in this notice.Concern for potential
thermal stratification
in the HPCI piping is related to three events in pressurized-water
reactors (PWRs) that were the basis for issuing NRC Bulletin 88-08 and the three supplements
to that bulletin.
These events occurred in one of the Farley units and in two foreign reactors.
In all of the events, water leaked either from or to the reactor coolant system through closed valves in an emergency
coolant system. Thermal stratification
of water in the piping of the emergency
coolant system and fluctuations
of the interface
between the hot and cold streams of water resulted in thermal fatigue and cracking of the piping wall in the heat-affected
zones of welds and in the base metal. For these reactors, the configuration
of the piping between the reactor coolant system and the first valve in the emergency
cooling system is approximately
like the configuration
of the piping at Dresden. The licensee for Dresden does intend to examine the piping ultrasonically
at the next scheduled
outage to determine
whether detectable
damage has occurred.During the event at Dresden, the potential
for steam bindingv the HPCI pump existed because the discharge
valve was normally open. Events have occurred in PWRs that have resulted in steam binding of auxiliary
pumps.Because the NRC staff was concerned
about the availability
of the auxiliary
-$ '
'4, IN 89-80 December 1, 1988 feedwater
pumps when needed to mitigate the consequences
of an accident, the staff Issued NRC Bulletin 85-01. The bulletin required that certain licensees develop Procedures
for monitoring
the temperature
of the pump discharge
to ensure that it remains at less than saturation
temperature
and to identify steam binding and restore the operability
of the system if it occurs.The NRC may issue additional
information
as more inspection
and analysis is completed.
This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact one of the technical
contacts listed below or the appropriate
NRR project manager. I* e4 Charles E. Rossi, Drec Division of Operational
Events Assessment
Office of Nuclear Reactor Regulation
Technical
Contacts:
Eric W. Weiss, AEOD (301) 492-9005 Roger Woodruff, NRR (301) 492-1180 Attachments:
1. Dresden 2 -High-Pressure
Coolant Injection
Line 2. Referenced
Generic Communications
3. List of Recently Issued NRC Information
Notices I
_ , r 1.5/1 1/89 7/18 /89 1 0/23/89 A 140 F 175 F 248 F B 180 F 220 F 275 F c INJECTION VALVES D I SCHARGE VALVE B FEEDWATER A FPC I PUMP TEST RETURN*(DRESDEN 2 -HIGH-PRESSURE
COOLANT INJECTION
LINE ul 0 C- +VD (D oFr a to c-, CD (D CO O CD CX)o -1 CDM..0
Attachment
2 IN 89-80 December 1, 1989 REFERENCED
GENERIC COMMUNICATIONS
1. 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 Valves Causes Loss of Feedwater
System Integrity
and Water Hammer Damage," January 1, 1986.3. NRC Information
Notice No. 87-10, "Potential
for Water Hammer During Restart of Residual Heat Removal Pumps," February 2, 1987.4. NRC Information
Notice No. 88-13, "Water Hammer and Possible Piping Damage Caused by Misapplication
of Kerotest Packless Metal Diaphragm
Globe Valves," April 18, 1988.5. NRC Bulletin 85-01, "Steam Binding of Auxiliary
Pumps," October 29, 1985.6. NRC Bulletin No. 88-08, "Thermal Stresses in Piping Connected
to Reactor Coolant Systems," June 22, 1988; Supplement
1, June 24, 1988; Supplement
2, August 4, 1988; and Supplement
3, April.11, 1988.
Attachment
3 IN 89-80 December 1, 1989 LIST OF RECENTLY ISSUED NRC INFORMATION
NOTICES Information
Date of Notice No. Subject Issuance Issued to 89-79 89-56, Supp. 1 89-78.89-77 Degraded Coatings and Corrosion
of Steel Containment
Vessels Questionable
Certification
of Material Supplied to the Defense Department
by Nuclear Suppliers Failure of Packing Nuts on One-Inch Uranium Hexafluoride
Cylinder Valves Debris in Containment
Emergency
Sumps and Incorrect
Screen Configurations
Agent: Zebra Mussel Falsification
of Welder Qualifications
for Contractor
Employees Clarification
of Trans-portation
Requirements
Applicable
to Return of Spent Radiopharmacy
Dosages from Users to Suppliers Potential
Overpressurization
of Low Pressure Systems 12/1/89 11/22/89 11/22/89 11/21/89 11/21/89 11/20/89 11/7/89 11/1/89 All holders of OLs or CPs for LWRs.All holders of OLs or CPs for nuclear power reactors.All NRC licensees authorized
to possess and use source material and/or special nuclear material for the heating, emptying, filling, or shipping of uranium hexafluoride
in 30-and 48-inch diameter cylinders.
All holders of OLs or CPs for PWRs.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All manufacturers
and distributors
of radiopharmaceuticals
for medical use, nuclear pharmacies, and medical licensees.
All holders of OLs or CPs for nuclear power reactors.89-76 89-75 89-74 89-73 OL = Operating
License CP = Construction
Permit
IN 89-80 December 1, 1988 feedwater
pumps when needed to mitigate the consequences
of an accident, the staff issued NRC Bulletin 85-01. The bulletin required that certain licensees develop procedures
for monitoring
the temperature
of the pump discharge
to ensure that it remains at less than saturation
temperature
and to identify steam binding and restore the operability
of the system if it occurs.The NRC may issue additional
information
as more inspection
and analysis is completed.
This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact one of the technical
contacts listed below or the appropriate
NRR project manager.Charles E. Rossi, Director Division of Operational
Events Assessment
Office of Nuclear Reactor Regulation
Technical
Contacts: Eric W. Weiss, AEOD (301) 492-9005 Roger (301)Woodruff, NRR 492-1180 Attachments:
1. Dresden 2 -High-Pressure
Coolant Injection
Line 2. Referenced
Generic Communications
3. List of Recently Issued NRC Information
Notices*SEE PREVIOUS CONCURRENCE
EAB: NRR*RWoodruff:db
11/12/89 C:PB1:RIII
- WShafer 11/13/89 IRB:AEOD*EWeiss 11/14/89 C:EAB:NRR*CHaughney
11/15/89 TECH EDITOR*RSanders 11/15/89 C:OGCB:NRR
- CBerlinger
11/22/89 EAB:NRR*PBaranowsky
11/1§/89 D:06A.CERossi DO 11/;1/89 PM:PD32:NRR
- BSiegel 11/15/89 I NRCIN 88-xx November x, 1988 monitoring
the temperature
of the pump discharge
to ensure that it is at less than saturation
temperature
and to identify steam binding if it occurs.The NRC may issue additional
information
as more inspection
and analysis is completed.
No specific action or written response is required by this information
notice. If you have questions
about this matter, please call one of the technical
contacts listed below or the Regional Administrator
of the appropriate
regional office.Charles E. Rossi, Director Division of Operational
Events Assessment
Office of Nuclear Reactor Regulation
Technical
Contacts: Eric W. Weiss, AEOD (301) 492-9005 Roger Woodruff, NRR (301) 492-1180 Attachments:
1. Dresden 2 -High-Pressure
Coolant Injection
Line 2. List of Recently Issued Information
Notices*SEE PREVIOUS EAB:NRR*RWoodruff:db
11/ /89 C:PB1:RIII
- WShafer 11/ /89 CONCURRENCE
IRB:AEOD*EWeiss 11/ /L6 TECH EDITOR EAB:NRR PBaranomsky
11/1 5/89 PM:PD32:NRR
BSiegelrP 11115189 Ko D:DOEA:NRR
CERossi 11/ /89 1 /WY/89 Doc: 299A
4.1.d NRCIN 88-xx November x, 1988 temperature
of the pump discharge
to assure that it is at less than saturation
temperature
and to identify steam binding if it occurs.The NRC may issue additional
information
as more inspection
and analysis is completed.
No specific action or written response is required by this information
notice. If you have questions
about this matter, please call one of the technical
contacts listed below or the Regional Administrator
of the appropriate
regional office.Charles E. Rossi. Director Division of Operational
Events Assessment
Office of Nuclear Reactor Regulation
Technical
Contacts: Eric W. Weiss, AEOD (301) 492-9005 Roger Woodruff, NRR (301) 492-1180 Attachments:
1. Dresden 2 -High Pressure Coolant Injection
Line 2. List of Recently Issued Information
Notices EAB:NRR RWoodruff:db
11/11189 3BM tricpkoa~C:PB1:RILI~
WShafer-Cd,'
11/13/89 IRB:AEOD EWei S 11/1 /89 C:EAB:NRR CHaughney 11/ /89 TECH EDITOR 11/1ST/89 C:OGCB:NRR
CBerlinger
11/ /89 EAB:NRR PBaranowsky
11/ /89 PM:PD32:NRR
BSiegel 11/ /89 D:DOEA:NRR
CERossi 11/ /89