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 3500F,
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 2750F and at the discharge of the HPCI pump to 2460F.
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.
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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 feedwater 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
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Attachment 2
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 Feedwater 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
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
Biofouling 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
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
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
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
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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