Information Notice 1994-58, Reactor Coolant Pump Lube Oil Fire
lQ
UNITED STATES
C,
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
August 16, 1994 NRC INFORMATION NOTICE 94-58: REACTOR COOLANT PUMP LUBE OIL FIRE
Addressees
All holders of operating licenses or construction permits for pressurized- water reactors.
Purnose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to a problem that may exist with the oil collection
system for the lube oil system components of reactor coolant pumps. 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 contained in this information notice are not
NRC requirements; therefore, no specific action or written response is
required.
DescriDtion of Circumstances
Haddam Neck Plant
On July 11,
1994, while operating at 100 percent power, the licensee for the
Haddam Neck Plant received a low oil level alarm for the upper lube oil
reservoir of reactor coolant pump No. 3. The licensee later observed that the
upper bearing temperature for reactor coolant pump No. 3 had been increasing
for approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> prior to receiving the low oil level alarm and
reached 82 *C [180 OF].
The licensee began a controlled power reduction to
bring the plant to a power level condition which would allow the reactor
coolant pump to be taken out of service. Simultaneously, a maintenance crew
was entering containment to fill the oil reservoir. Upon entering
containment, the maintenance crew observed smoke Just inside the airlock. At
this time, the upper bearing temperature reached nearly 93 *C [200 OF], and
the licensee manually tripped the reactor from approximately 50 percent power.
The heat detectors installed above the reactor coolant pump went into alarm
approximately 50 minutes later. At about the same time, the fire brigade
entered containment and reported a fire in the insulation around the pump
casing and nearby piping of reactor coolant pump No. 3. The fire brigade
removed insulation and extinguished the fire using portable dry chemical fire
extinguishers. A relief crew later observed a reflash on the remaining
insulation, removed this insulation, and extinguished the second fire.
The licensee determined that the oil leak and subsequent fire resulted from a
crack in a 1-inch diameter, schedule 80, threaded PVC fitting in the pump lube
oil system. The PVC fitting was installed between the reactor coolant pump
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4-58 Yugust 16, 1994 oil reservoir and the oil lift pump to electrically isolate the oil lift pump
from the reactor coolant pump motor. The oil leaking from the crack was not
properly collected and routed away from high velocity cooling air, which blew
the oil onto the insulation on the pump casing and pipe. The cooling air came
from the reactor coolant pump motor and the area ventilation system. The high
temperature of the reactor coolant system (approximately 282 C [540 *F])
ignited the oil-soaked insulation.
(The flash point of the lube oil is
approximately 204 'C [400 'F].)
The reservoir retained about 455 liters
[120 gallons] of the approximately 755 liters (200 gallons] of oil originally
in the reservoir. About about 150 liters (40 gallons] of oil was collected by
the oil collection system, and 150 liters [40 gallons] leaked onto the
insulation and the containment floor.
Millstone Nuclear Power Station. Unit 2
On July 27, 1994, the lube oil low flow alarm for the 'A' reactor coolant pump
annunciated at Millstone Unit 2. Plant operators began reducing reactor power
in accordance with plant procedures.
Licensee personnel inspected all of the
reactor coolant pumps and found that oil had dripped from the tops of the 'A'
and 'D' pump motors, coating the outside of the motors. Most of the oil was
contained by the oil collection drip pans; however, some of the oil that
leaked from the 'A' pump motor was not contained.
Based on the observed fire
hazard in containment, the licensee shut down the plant.
After the plant was shut down, an NRC inspector examined the lube oil
collection system and the area around the reactor coolant pumps. There were a
number of small oil leaks on each pump motor although there was more leakage
from the 'A' pump motor. The inspector observed that various equipment around
the 'A' reactor coolant pump was coated with a film of oil and he estimated
that several gallons of oil had collected in various areas outside the oil
collection system. The inspector also noted that portions of the lube oil
system were outside the oil collection system and that the collection system
piping did not appear to be large enough to accommodate the largest potential
oil leak.
Discussion
In pressurized-water reactors, each reactor coolant pump motor typically
contains between 530 and 830 liters [140 and 220 gallons) of oil.
Oil leaking
from the lube oil system may come in contact with either (1) surfaces that are
hot enough to ignite the oil, or (2) an electrical source of ignition.
Appendix R to Part 50 of Title 10 of the Code of Federal Regulations requires
the installation of an oil collection system to collect oil from all potential
pressurized and unpressurized leakage sites. An adequately designed, installed, and maintained oil collection system is necessary to contain any
oil released because of leakage or failure of the lubrication system and to
minimize fire hazards by draining the oil to a safe location.
There are a number of differences between the reactor coolant pump motors and
their associated lube oil systems at Millstone Unit 2 and Haddam Neck.
For
example, the Millstone Unit 2 motors do not use PVC or other synthetic
couplings in the lube oil system. The Millstone Unit 2 reactor coolant pump
V
<\\,AN 94-58 August 16, 1994 motors are manufactured by General Electric Company while the motors at Haddam
Neck are manufactured by Westinghouse Electric Corporation. However, the oil
collection systems at the two plants are similar.
The Haddam Neck oil collection system is intended to collect lube oil from all
potential leakage sites and to drain it to a vented, closed container to
prevent a fire during normal conditions or design basis accident conditions.
However, in this event the catch pan design, which relied on an unshielded
vertical flow of oil, was not adequate. This design allowed the air flow
around the motor to affect the vertical movement of the dripping oil and
allowed it to escape the collection system. To a lesser extent, the
ventilation system also created air currents in the vicinity of the pump, which prevented some of the oil from being collected.
The licensee is installing a steel dielectric union on each reactor coolant
pump motor at Haddam Neck to replace the PVC fitting which failed and caused
the leak in this event. The licensee is also modifying the oil collection
system to account for air currents near the reactor coolant pumps.
The ventilation system for the Millstone Unit 2 containment does not
contribute to the air flow around the reactor coolant pump motors. The only
air flow in this area is caused by the motor itself. In addition, Millstone
Unit 2 has installed mirror insulation on some of the piping in the vicinity
of the reactor coolant pumps. This type of insulation would prevent oil from
coming in contact with and igniting on the high temperature piping it
insulates. These factors reduce, but do not eliminate, the likelihood of
leaking lube oil reaching an ignition source. However, the design of the
existing oil collection system was inadequate to contain existing and
potential oil leakage paths. The licensee is evaluating modifications that
can be installed during the current forced outage to ensure that the lube oil
collection system for the reactor coolant pump motors meets the requirements
of Appendix R.
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 Office of
Nuclear Reactor Regulation (NRR) project manager.
Brian K. Grimes, Director
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts: Edward A. Connell, NRR
(301) 504-2838
Ralph J. Paolino, RI
(610) 337-5285 Attachment:
List of Recently Issued NRC Information Notices
Att&,.Aent
August 16, 1994 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
94-57
94-56
94-55
91-79, Supp. 1
Debris in Containment
and the Residual Heat
Removal System
Inaccuracy of Safety Valve
Set Pressure Determinations
Using Assist Devices
Problems with Copes-
Vulcan Pressurizer
Power-Operated Relief
Valves
Deficiencies Found in
Thermo-Lag Fire Barrier
Installation
Failures of General
Electric Magne-Blast
Circuit Breakers to
Latch Closed
Possible Malfunction of
Westinghouse ARD, BFD,
and NBFD Relays, and
A200 DC and DPC 250
Magnetic Contactors
08/12/94
08/11/94
08/04/94
08/04/94
08/01/94
07/29/94
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
94-54
91-45, Supp. 1
94-42, Supp. 1
Cracking in the Lower
Region of the Core Shroud
in Boiling-Water Reactors
07/19/94 All holders
for boiling
(BWRs).
water reactors
94-53
94-52
Hydrogen Gas Burn Inside
Pressurizer During Welding
Inadvertent Containment
Spray and Reactor Vessel
Draindown at Millstone
Unit 1
07/18/94
07/15/94
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
OL - Operating License
CP - Construction Permit
IJN 94-58 August 16, 1994 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 Office of
Nuclear Reactor Regulation (NRR) project manager.
Original signed by
Brian K. Grimes
Brian K. Grimes, Director
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts:
Edward A. Connell, NRR
(301) 504-2838
Ralph J. Paolino, RI
(610) 337-5285 Attachment:
List of Recently Issued NRC Information Notices
rnL'- P
-fiicAI-
- See previous
- SPLB:DSSA
EAConnell
07/21/94 concurrence
- DRS:RI
RJPaolino
07/21/94
- OGCB:DORS
PCWen
07/21/94
- TECH ED
JMain
07/21/94
- SC/DSP:RI
WHRuland
07/21/94
- C/OEAB:DORS
AEChaffee
07/26/94
- SC/SPLB:DSSA
SKWest
07/21/94
- AC/OGCB:DORS
ElDoolittle
07/28/94
- C/SPLB:DSSA
CEMcCRACKEN
07/2Z19402/
- AD/DSSA
MJVirgil io
07/25/94
08//o/94
OFFICIAL RECORD COPY
DOCUMENT NAME:
94-58. IN
NOTES:
- The PM was informed of the development of this Infor. Notice.
- The licensee was consulted with the technical content of this
Infor. Notice, and its comments were incorporated.
Subsequently, the final version was shown to R. Paolino (RI) and P. Madden (SPLB).
They have no further comments.
- This version also addressed OEAB's comments.
\\_J IN 94-xx
August xx, 1994 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 Office of
Nuclear Reactor Regulation (NRR) project manager.
Brian K. Grimes, Director
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts: Edward A. Connell, NRR
(301) 504-2838
Ralph J. Paolino, RI
(610) 337-5285 Attachment:
List of Recently Issued NRC Information Notices
- See previous
- SPLB:DSSA
EAConnell
07/21/94 concurrence
- DRS:RI
RJPaolano
07/21/94
- OGCB: DORS
PCWen
07/21/94
- TECH ED
JMain
07/21/94
- SC/DSP:RI
WHRuland
07/21/94
- SC/SPLB:DSSA
SKWest
07/21/94
- C/SPLB:DSSA
CEMcCRACKEN
07/22/94
- AD/DSSA
MJVirgilio
07/25/94
- C/OEAB:DORS
AEChaffee
07/26/94
- AC/OGCB:DORS
ELDoolittle
07/28/94 D/DORS
BKGrimes9fL
08/ /94 v
OFFICIAL RECORD COPY
DOCUMENT NAME:
HADMNECK.IN
NOTES:
- The PM was informed of the development of this Infor. Notice.
- The licensee was consulted with the technical content of this
Infor. Notice, and its comments were incorporated. Subsequently, the final version was shown to R. Paolino (RI) and P. Madden (SPLB).
They have no further comments.
- This version also addressed OEAB's comments.
'->IN 94-xx
July xx, 1994 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 Office of
Nuclear Reactor Regulation (NRR) project manager.
Brian K. Grimes, Director
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts: Edward A. Connell, NRR
(301) 504-2838
Ralph J. Paolino,RI
(610) 337-5285 Attachment:
List of Recently Issued NRC Information Notices
- See previous
- SPLB:DSSA
EAConnell
07/21/94 concurrence
- DRS:RI
RJPaolino
07/21/94
- OGCB:DORS
PCWen
07/21/94
- TECH ED
JMain
07/21/94
- SC/DSP:RI
WHRuland
07/21/94
- SC/SPLB:DSSA
SKWest
07/21/94 AC
RS
E
le
- C/SPLB:DSSA
CEMcCRACKEN
07/22/94
- AD/DSSA
MJVirgilio
07/25/94
- C/OEAB:DORS
AEChaffee
07/26/94 D/DORS
BKGrimes
07/ /94 1,0-w
OFFICIAL RECORD COPY
DOCUMENT NAME:
HADMNECK.IN
NOTES:
- The PM was informed of the development of this Infor.
- The licensee was consulted with the technical content
Infor. Notice, and its comments were incorporated. Si
the final version was shown to R. Paolino (RI) and P.
They have no further comments.
- This version also addressed OEAB's comments.
Notice.
of this
ubsequently, Madden (SPLB)
~t.
7A/94
'JIN 94-xx
July xx, 1994 The licensee is considering flanged connections to replace the PVC fittings.
The licensee is also modifying the oil collection system to account for the
air currents near the RCPs.
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 Office of
Nuclear Reactor Regulation (NRR) project manager.
Brian K. Grimes, Director
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts:
Edward A. Connell, NRR
(301) 504-2838
Ralph J. Paolino,RI
(610) 337-5285 Attachment:
List of Recently Issued NRC Information Notices
- See previous concurrence
- SPLB:DSSA
- DRS:RI
EAConnell
RJPaolino
07/21/94
07/21/94
- SC/DSP:RI
- SC/SPLB:DSSA
WHRuland
SKWest
07/21/94
07/21/94 C
G
l ORS
AC/OGCB:DORS
A0a
ffee
ELDoolittle
07/A/94
07/ /94
OFFICIAL RECORD COPY
- OGCB:DORS
PCWen
" P
CEMcCRACKEN
07/Ap94 s
D/DORS
BKGrimes
07/ /94
- TECH ED
JMain
07/21/94 AD/DSSAOA '
MJVirqilio
07/$6/94 DOCUMENT NAME:
HADNECK.RI
V',-AN 94-xx
July xx, 1994 The licensee is considefing flanged connections to replace the PVC fittings.
The licensee is also modifying the oil collection system to account for the
air currents near the RCPs.
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 Office of
Nuclear Reactor Regulation (NRR) project manager.
Brian K. Grimes, Director
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts:
Edward A. Connell, NRR
(301) 504-2838 Ralph
(610)
J. Paolino,RI
337-5285 Attachment:
List of Recently Issued NRC Information Notices
SPLB:DSSA
EAConnell
07/Z/ /94 SC/DSP: R
WHRul and
-8 07/%1/94 C/OEAB:DORS
AEChaffee
07/ /94 DRS:RI
RJPaol ino
07 I/94 SKWest
07/t- /94 AC/OGCB:DORS
ELDoolittle
07/ /94 OGCB:gQRS
PCWen 1-
07,l1/94 C/SPLB:DSSA
CEMcCRACKEN
07/ /94 TECH ED
JMain asp
07/21/94 AD/DSSA
MJVirgilio
07/ /94 D/DORS
BKGrimes
07/ /94
OFFICIAL RECORD COPY
DOCUMENT NAME:
HADNECK.RI