Information Notice 1994-76, Recent Failures of Charging/Safety Injection Pump Shafts: Difference between revisions

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{{#Wiki_filter:4 UNITED STATES NUCLEAR REGULATORY
{{#Wiki_filter:4 UNITED STATES


COMMISSION
NUCLEAR REGULATORY COMMISSION


===OFFICE OF NUCLEAR REACTOR REGULATION===
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 October 26, 1994 NRC INFORMATION


NOTICE 94-76: RECENT FAILURES OF CHARGING/SAFETY
WASHINGTON, D.C. 20555 October 26, 1994 NRC INFORMATION NOTICE 94-76:   RECENT FAILURES OF CHARGING/SAFETY INJECTION


INJECTION PUMP SHAFTS
PUMP SHAFTS


==Addressees==
==Addressees==
All holders of operating
All holders of operating licenses or construction permits for pressurized
 
licenses or construction
 
permits for pressurized


water rekctors.
water rekctors.


==Purpose==
==Purpose==
The U.S. Nuclear Regulatory
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information


Commission (NRC) is issuing this information
notice (IN)to alert addressees to recent failures of charging/safety


notice (IN) to alert addressees
injection pump shafts at facilities designed by the Westinghouse Electric


to recent failures of charging/safety
Corporation (Westinghouse). It is expected that recipients will review the


injection
information for applicability to their facilities and consider actions, as


pump shafts at facilities
appropriate, to avoid similar problems. However, suggestions contained in


designed by the Westinghouse
this information notice are not NRC requirements; therefore, no specific


Electric Corporation (Westinghouse).
action or written response is required.


It is expected that recipients
Background                                                  4 At Westinghouse-designed facilities, charging/safety injection pumps have


will review the information
4 ction flow to the reactor coolant


for applicability
three funct ons: (1) to deliver seal iri


to their facilities
pumps, (2) .o eliver makeup water flcv ) the reactor coolant system, and


and consider actions, as appropriate, to avoid similar problems.
(3) to deliver high head safety injection and recirculation flow to the


However, suggestions
reactor coolant system during and after a loss-of-coolant accident. During


contained
normal operation, one of two, or in some cases, one of three pumps is always


in this information
in operation to deliver seal injection and makeup water flow. The loss of an


notice are not NRC requirements;
inservice charging/safety injection pump creates a condition that may
therefore, no specific action or written response is required.Background


4 At Westinghouse-designed
challenge reactor coolant pump seal integrity and, if makeup water flow is not


facilities, charging/safety
restored in a timely manner, can result in a loss of coolant inventory.


injection
On February 29, 1980, the NRC issued IN 80-07, "Pump Shaft Fatigue Cracking,"
  to alert recipients to failures of charging/safety injection pump shafts that


pumps have three funct ons: (1) to deliver seal iri 4 ction flow to the reactor coolant pumps, (2) .o eliver makeup water flcv ) the reactor coolant system, and (3) to deliver high head safety injection
occurred during the 1970s. All of the charging/safety injection pump shafts


and recirculation
addressed in that notice were procured by Westinghouse from the Pacific Pump


flow to the reactor coolant system during and after a loss-of-coolant
Division of Dresser Industries (now Ingersoll-Dresser Pump Co). Actions taken


accident.
at that time to correct the problem included design modifications, changes in


During normal operation, one of two, or in some cases, one of three pumps is always in operation
the heat treatment of the shaft material, and the use of formed cutting tools


to deliver seal injection
during fabrication. Also, abnormal operation of the pumps such as operation


and makeup water flow. The loss of an inservice
with a partial or complete loss of fluid or with high vibration present was


charging/safety
found to be a significant contributor to the shaft failures. The Westinghouse


injection
Nuclear Service Division issued Technical Bulletins TB-77-", TB-78-1, and


pump creates a condition
TB-79-6, to provide guidance on vibration monitoring, operation and


that may challenge
maintenance of the pumps, and allowable vibration amplitude limits.


reactor coolant pump seal integrity
9410200153    4 gfokC  4  On    P4R          C AI 0+ic4V


and, if makeup water flow is not restored in a timely manner, can result in a loss of coolant inventory.
Iae


On February 29, 1980, the NRC issued IN 80-07, "Pump Shaft Fatigue Cracking," to alert recipients
vJ


to failures of charging/safety
IN 94-76 October 26, 1994 Recent events indicate that failures of charging/safety injection pump shafts


injection
continue to be a problem.


pump shafts that occurred during the 1970s. All of the charging/safety
==Description of Circumstances==


injection
===Sequoyah Unit 1===
  On February 18, 1991, plant operators for Sequoyah Unit 1 received indications


pump shafts addressed
of decreasing flow and increasing motor current on charging pump IB-B. When


in that notice were procured by Westinghouse
efforts to restore full flow failed, they declared the pump inoperable and


from the Pacific Pump Division of Dresser Industries (now Ingersoll-Dresser
began shutting down the reactor as required by plant technical specifications.


Pump Co). Actions taken at that time to correct the problem included design modifications, changes in the heat treatment
Charging pump lB-B had been in operation for several months and had shown no


of the shaft material, and the use of formed cutting tools during fabrication.
previous signs of degradation. The licensee disassembled the pump, found


Also, abnormal operation
heavy wear on the impeller shoulders and the balance drum, and found a


of the pumps such as operation with a partial or complete loss of fluid or with high vibration
280-degree crack in the shaft near the 11th stage impeller. Westinghouse


present was found to be a significant
analyzed the shaft and determined that the crack had been in the shaft for


contributor
several months (possibly years) and that the rotating element was of the


to the shaft failures.
improved type referred to in IN 80-07. The licensee replaced +he rotating


===The Westinghouse===
element and, after testing the pump successfully, returned the pump to
Nuclear Service Division issued Technical


Bulletins
service. [Licensee Event Report (LER) 50-327/91-003]
Callaway


TB-77-", TB-78-1, and TB-79-6, to provide guidance on vibration
On February 2, 1992, the Union Electric Company Callaway Plant was at power


monitoring, operation
and charging pump B was in service to support operations. Plant operators


and maintenance
received indications of zero flow in the charging header and at the reactor


of the pumps, and allowable
coolant pump seal. The operators placed charging pump A iA service to restore


vibration
normal flow, and pump B tripped. Plant personnel inspected pump B and found


amplitude
that the shaft had sheared on the outboard end between the balance drum lock


limits.9410200153 gf 4 okC 4 P4R On C AI 0+ic 4V Iae
nut an, balance drum mating area. le licensee documented the failure in


vJ IN 94-76 October 26, 1994 Recent events indicate that failures of charging/safety
Suggestion Occurrence Solution 92-10 and replaced the failed shaft.


injection
Shearon Harris


pump shafts continue to be a problem.Description
On March 18, 1993, operators at the Shearon Harris plant received indications


of Circumstances
of a shaft failure on charging/safety injection pump B. The indications were


Sequoyah Unit 1 On February 18, 1991, plant operators
high motor current, low charging flow, and low pump discharge pressure. The


for Sequoyah Unit 1 received indications
operators secured pump B from service and placed pump A in service. Plant


of decreasing
personnel uncoupled the pump from the motor and found that the pump shaft had


flow and increasing
sheared under the balancing drum lock nut. This was the same location as in


motor current on charging pump IB-B. When efforts to restore full flow failed, they declared the pump inoperable
three failures that occurred in the 1970s. (LER 50-400/93-005)


and began shutting down the reactor as required by plant technical
===D.C. Cook Unit 2===
In July 1993, at D.C. Cook Unit 2, a charging pump failed a surveillance test


specifications.
when it could not deliver the required 454 liters [120 gallons] per minute.


Charging pump lB-B had been in operation
The rotating element in that pump had been installed in 1987. The licensee


for several months and had shown no previous signs of degradation.
disassembled the pump and found a 10 centimeter [4 inch!, 180 degree


The licensee disassembled
circumferential crack through the number 9 impeller shaft keyway. Smaller


the pump, found heavy wear on the impeller shoulders
cracks were found in two other impeller keyway areas. (LER 50-316/93-006)


and the balance drum, and found a 280-degree
IN 94-76 October 26, 1994 Braidwood Unit 1 and Sequoyah Unit 2 The NRC staff has received information on two other recent failures of


crack in the shaft near the 11th stage impeller.
charging/safety injection pump shafts: (1) on September 15, 1993, at the


===Westinghouse===
Braidwood Nuclear Station Unit 1 (Braidwood), a charging/safety injection pump
analyzed the shaft and determined


that the crack had been in the shaft for several months (possibly
shaft sheared between the 10th and 11th stage impellers, and (2) on


years) and that the rotating element was of the improved type referred to in IN 80-07. The licensee replaced +he rotating element and, after testing the pump successfully, returned the pump to service. [Licensee
February 7, 1994, at Sequoyah Unit 2, a charging\safety injection pump shaft


Event Report (LER) 50-327/91-003]
failed, resulting in a reactor shutdown as required by plant technical
Callaway On February 2, 1992, the Union Electric Company Callaway Plant was at power and charging pump B was in service to support operations.


Plant operators received indications
specifications. The licensee for Braidwood replaced the pump shaft and


of zero flow in the charging header and at the reactor coolant pump seal. The operators
documented the failure on Problem Investigation Report 456-200-93-03600. The


placed charging pump A iA service to restore normal flow, and pump B tripped. Plant personnel
licensee for Sequoyah reported that the affected pump had not exhibited any


inspected
indication of degradation before the shaft failure and that, similar to many


pump B and found that the shaft had sheared on the outboard end between the balance drum lock nut an, balance drum mating area. le licensee documented
of the other shaft failures, the shaft had failed near the location of the


the failure in Suggestion
balancipng drum lock nut. (LER 50-328/94-002)
  Discussion


Occurrence
Charging/safety injection pumps are important for normal plant operation and


Solution 92-10 and replaced the failed shaft.Shearon Harris On March 18, 1993, operators
for core cooling during accidents such as a small break loss-of-coolant


at the Shearon Harris plant received indications
accident. Fcr most of the failure events described above, determination of


of a shaft failure on charging/safety
the root cause of the failure was inconclusive. However, the operational


injection
histories of many of the failed shafts showed that they had been operated with


pump B. The indications
void formation, gas entrainment, or other abnormal conditions within a few


were high motor current, low charging flow, and low pump discharge
years of the failure. Operation of the pumps under these conditions may have


pressure.
caused or contributed to the later failure of the shafts. Avoiding operation


The operators
of charging pumps under abnormal conditions and maintaining vibration levels


secured pump B from service and placed pump A in service. Plant personnel
within manufacturer recommendations may increase pump reliability. To


uncoupled
increase the benefit of predictive maintenance programs, Wbstinghouse


the pump from the motor and found that the pump shaft had sheared under the balancing
recommends that pump vibrations be monitored at least monthly; preferably, every two weeks. This is more frequent than is required by Section XI of the


drum lock nut. This was the same location as in three failures that occurred in the 1970s. (LER 50-400/93-005)
ASME B iler and Pressure Vessel Code. V'stinghouse will provide recommended
D.C. Cook Unit 2 In July 1993, at D.C. Cook Unit 2, a charging pump failed a surveillance


test when it could not deliver the required 454 liters [120 gallons] per minute.The rotating element in that pump had been installed
vibration limits upon request.


in 1987. The licensee disassembled
Industry experience in detecting shaft failures in pumps such as the reactor


the pump and found a 10 centimeter
coolant pump and the recirculation pump is relevant to monitoring programs of


[4 inch!, 180 degree circumferential
charging/safety injection pumps because the precursors to shaft failure are


crack through the number 9 impeller shaft keyway. Smaller cracks were found in two other impeller keyway areas. (LER 50-316/93-006)
similar. For those pumps, monitoring phase angles as well as monitoring
IN 94-76 October 26, 1994 Braidwood


Unit 1 and Sequoyah Unit 2 The NRC staff has received information
vibration amplitude is considered to be important in detecting shaft


on two other recent failures of charging/safety
degradation. These data are routinely trended by some licensees for detection


injection
of impending shaft failures.


pump shafts: (1) on September
A description of the analyses and conclusions for some of the above events


15, 1993, at the Braidwood
follows:
Westinghouse evaluated seven possible root causes for the shaft failure at


Nuclear Station Unit 1 (Braidwood), a charging/safety
Callaway, including material defects, design flaws, errors in fabrication or


injection
processing, assembly or installation defects, off-design or unintended service


pump shaft sheared between the 10th and 11th stage impellers, and (2) on February 7, 1994, at Sequoyah Unit 2, a charging\safety
conditions, maintenance deficiencies, and improper operation. Westinghouse


injection
concluded that the shaft failure was most likely the result of a 1986 event in


pump shaft failed, resulting
which the pump had experienced a loss of suction water flow for approximately


in a reactor shutdown as required by plant technical specifications.
seven minutes. The loss of suction flow increased the vapor-to-liquid ratio


The licensee for Braidwood
in the pump and caused a dynamic imbalance. Events of this type could cause


replaced the pump shaft and documented
K>~
                                                                IN 94-76 October 26, 1994 immediate pump failure or cause cyclic fatigue damage that could lead to


the failure on Problem Investigation
premature shaft failure at a later date.


Report 456-200-93-03600.
A gas entrainment event that occurred on August 20, 1990, was determined to be


The licensee for Sequoyah reported that the affected pump had not exhibited
the probable cause of the shaft failure at Sequoyah Unit 2. Problems caused


any indication
by gas entrainment are discussed in NRC Information Notice 88-23, "Potential


of degradation
for Gas Binding of High-Pressure Safety Injection Pumps During a Design Basis


before the shaft failure and that, similar to many of the other shaft failures, the shaft had failed near the location of the balancipng
Accident," and its supplements.


drum lock nut. (LER 50-328/94-002)
Westinghouse considers an operational phenomenon, such as gas entrainment, may
Discussion


Charging/safety
have led to the shaft failure at Shearon Harris, although the licensee found


injection
no evidence of gas pockets in the charging system. In May 1991 (two years


pumps are important
before-the shaft failure), the licensee reported to the NRC that the charging


for normal plant operation
system had been in a degraded condition during the previous operating cycle.


and for core cooling during accidents
An NRC Special Inspection Team reviewed the event and determined that several


such as a small break loss-of-coolant
water hammer events could have occurred in the system as a result of


accident.
weaknesses in the design of the alternate minimum flow system. The NRC issued


Fcr most of the failure events described
IN 92-61, "Loss of High Head Safety Injection," and its supplement regarding


above, determination
that event. Another concern at Shearon Harris was the fact that the A and B


of the root cause of the failure was inconclusive.
charging/safety injection pumps are alternated at approximately 2-week


===However, the operational===
intervals. Therefore, each pump is started about 25 to 30 times each year.
histories


of many of the failed shafts showed that they had been operated with void formation, gas entrainment, or other abnormal conditions
Westinghouse believes the high number of starts also could contribute to early


within a few years of the failure. Operation
shaft failure. Problems associated with excessive pump starts include galled


of the pumps under these conditions
wear rings, increased vibration, and decreased pump performance. However, Westinghouse concluded that the available data were insufficient to directly


may have caused or contributed
link the failure of the shaft to the high number of pump starts.


to the later failure of the shafts. Avoiding operation of charging pumps under abnormal conditions
Although Westinghouse could not conclusively determine the root cause of the


and maintaining
shaft failure at Shearon Harris, West 'nghouse made recommendations which could


vibration
help pre-ent or detect impendine shaf fa;lures. Westinghou- suggested that


levels within manufacturer
the liceasee conduct a detailed review, of the possibility that gas could


recommendations
become entrained in the charging pump suction piping and the cross connczts to


may increase pump reliability.
other systems. Westinghouse also recommended that, when the rotating element


To increase the benefit of predictive
of the pump is replaced, consideration be given to installing the latest shaft


maintenance
design which has an improved one-piece balance drum lock nut. Westinghouse


programs, Wbstinghouse
included recommendations for vibration monitoring in Westinghouse Technical


recommends
Bulletin TB-79-6. Westinghouse has not specified a limitation on the number


that pump vibrations
of pump starts but recommends that pump starts be minimized to maintain pump


be monitored
reliability.


at least monthly; preferably, every two weeks. This is more frequent than is required by Section XI of the ASME B iler and Pressure Vessel Code. V'stinghouse
In addition to the industry actions described above, Westinghouse and the


will provide recommended
Westinghouse Owners Group (WOG) are implementing a program to address these


vibration
pump shaft failures. The program includes: (1) a survey of WOG member


limits upon request.Industry experience
utilities for pump service operating history data, (2) a pump design review, and (3) a shaft material enhancement evaluation. The program is intended to


in detecting
identify any weaknesses in design, maintenance, or operation of the pumps in


shaft failures in pumps such as the reactor coolant pump and the recirculation
order to improve shaft reliability.


pump is relevant to monitoring
I    S :. .


programs of charging/safety
. I


injection
IN 94-76 October 26, 1994 This information notice requires no specific action or written response. If


pumps because the precursors
you have any questions about the information in this notice, please contact


to shaft failure are similar. For those pumps, monitoring
the technical contact listed below or the appropriate Office of Nuclear


phase angles as well as monitoring
Reactor Regulation (NRR) project manager.


vibration
Brian K. Grimes, Director


amplitude
Division of Project Support


is considered
Office of Nuclear Reactor Regulation


to be important
Technical contact:  D. Roberts, RII


in detecting
(919) 362-0601 Attachment:
            List of Recently Issued NRC Information Notices


shaft degradation.
daret4s                      C'


These data are routinely
Attachment
 
trended by some licensees
 
for detection of impending
 
shaft failures.A description
 
of the analyses and conclusions
 
for some of the above events follows: Westinghouse
 
evaluated
 
seven possible root causes for the shaft failure at Callaway, including
 
material defects, design flaws, errors in fabrication
 
or processing, assembly or installation
 
defects, off-design
 
or unintended
 
service conditions, maintenance
 
deficiencies, and improper operation.
 
===Westinghouse===
concluded
 
that the shaft failure was most likely the result of a 1986 event in which the pump had experienced
 
a loss of suction water flow for approximately
 
seven minutes. The loss of suction flow increased
 
the vapor-to-liquid
 
ratio in the pump and caused a dynamic imbalance.
 
Events of this type could cause
 
K>~IN 94-76 October 26, 1994 immediate
 
pump failure or cause cyclic fatigue damage that could lead to premature
 
shaft failure at a later date.A gas entrainment
 
event that occurred on August 20, 1990, was determined
 
to be the probable cause of the shaft failure at Sequoyah Unit 2. Problems caused by gas entrainment
 
are discussed
 
in NRC Information
 
Notice 88-23, "Potential
 
for Gas Binding of High-Pressure
 
Safety Injection


Pumps During a Design Basis Accident," and its supplements.
IN 94-76 October 26, 1994 LIST OF RECENTLY ISSUED


Westinghouse
NRC INFORMATION NOTICES


considers
===Information                                  Date of===
Notice No.            Subject                Issuance  Issued to


an operational
93-60,        Reporting Fuel Cycle          10/20/94  All 10 CFR Part 70
Supp. 1        and Materials Events to                  fuel cycle licensees.


phenomenon, such as gas entrainment, may have led to the shaft failure at Shearon Harris, although the licensee found no evidence of gas pockets in the charging system. In May 1991 (two years before-the
the NRC Operations Center


shaft failure), the licensee reported to the NRC that the charging system had been in a degraded condition
94-75          Minimum Temperature            10/14/94  All holders of OLs or CPs


during the previous operating
for Criticality                          pressurized-water reactors


cycle.An NRC Special Inspection
(PWRs).


Team reviewed the event and determined
94-74          Facility Management            10/13/94  All U.S. Nuclear Regulatory


that several water hammer events could have occurred in the system as a result of weaknesses
Responsibilities for                      Commission Medical


in the design of the alternate
Purchased or Contracted                  Licensees.


minimum flow system. The NRC issued IN 92-61, "Loss of High Head Safety Injection," and its supplement
Services for Radiation


regarding that event. Another concern at Shearon Harris was the fact that the A and B charging/safety
Therapy Programs


injection
94-73          Clarification of Critical-    10/12/94  All fuel fabrication


pumps are alternated
ity Reporting Criteria                    facilities.


at approximately
94-72          Increased Control Rod          10/05/94  All'holders of OLs or CPs


2-week intervals.
Drop Time from Crud                      for pressurized water


Therefore, each pump is started about 25 to 30 times each year.Westinghouse
Buildup                                  reactors


believes the high number of starts also could contribute
94-71          Degradation of Scram          10/04/94  All holders of OLs or CPs
 
to early shaft failure. Problems associated
 
with excessive
 
pump starts include galled wear rings, increased
 
vibration, and decreased
 
pump performance.
 
However, Westinghouse
 
concluded
 
that the available
 
data were insufficient
 
to directly link the failure of the shaft to the high number of pump starts.Although Westinghouse
 
could not conclusively
 
determine
 
the root cause of the shaft failure at Shearon Harris, West 'nghouse made recommendations
 
which could help pre-ent or detect impendine
 
shaf fa;lures.
 
Westinghou- suggested
 
that the liceasee conduct a detailed review, of the possibility
 
that gas could become entrained
 
in the charging pump suction piping and the cross connczts to other systems. Westinghouse
 
also recommended
 
that, when the rotating element of the pump is replaced, consideration
 
be given to installing
 
the latest shaft design which has an improved one-piece
 
balance drum lock nut. Westinghouse
 
included recommendations
 
for vibration
 
monitoring
 
in Westinghouse
 
Technical Bulletin TB-79-6. Westinghouse
 
has not specified
 
a limitation
 
on the number of pump starts but recommends
 
that pump starts be minimized
 
to maintain pump reliability.
 
In addition to the industry actions described
 
above, Westinghouse
 
and the Westinghouse
 
Owners Group (WOG) are implementing
 
a program to address these pump shaft failures.
 
The program includes:
(1) a survey of WOG member utilities
 
for pump service operating
 
history data, (2) a pump design review, and (3) a shaft material enhancement
 
evaluation.
 
The program is intended to identify any weaknesses
 
in design, maintenance, or operation
 
of the pumps in order to improve shaft reliability.
 
I .S : ..I IN 94-76 October 26, 1994 This information
 
notice requires no specific action or written response.
 
If you have any questions
 
about the information
 
in this notice, please contact the technical
 
contact listed below or the appropriate
 
Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Project Support Office of Nuclear Reactor Regulation
 
Technical
 
contact: D. Roberts, RII (919) 362-0601 Attachment:
List of Recently Issued NRC Information
 
Notices daret4s
 
Attachment


IN 94-76 October 26, 1994 LIST OF RECENTLY ISSUED NRC INFORMATION
Solenoid Pilot Valve                      for boiling water reactors


NOTICES Information
Pressure and Exhaust                      (BWRs).


Date of Notice No. Subject Issuance Issued to 93-60, Supp. 1 94-75 94-74 94-73 94-72 94-71 94-70 94-69 94-68 Reporting
Diaphragms


Fuel Cycle and Materials
94-70          Issues Associated with Use    09/29/94  All U.S. Nuclear Regulatory


Events to the NRC Operations
of Strontium-89 and Other                Commission Medical


===Center Minimum Temperature===
Beta Emitting Radiopharma-                Licensees.
for Criticality


===Facility Management===
ceuticals
Responsibilities


for Purchased
94-69          Potential Inadequacies        09/28/94  All holders of OLs or CPs


or Contracted
in the Prediction of Torque              for nuclear power reactors.


Services for Radiation Therapy Programs Clarification
Requirements for and Torque


of Critical-ity Reporting
Output of Motor-Operated


Criteria Increased
Butterfly Valves


Control Rod Drop Time from Crud Buildup Degradation
94-68          Safety-Related Equip-        09/27/94  All holders of OLs or CPs


of Scram Solenoid Pilot Valve Pressure and Exhaust Diaphragms
ment Failures Caused by                    For nuclear power reactors.


Issues Associated
Faulted Indicating Lamps


with Use of Strontium-89 and Other Beta Emitting Radiopharma- ceuticals Potential
OL = Operating License


===Inadequacies===
CP = Construction Permit
in the Prediction


of Torque Requirements
: . .    I


for and Torque Output of Motor-Operated
IN 94-76 October 26, 1994 This information notice requires no specific action or written response. If


Butterfly
you have any questions about the information in this notice, please contact


Valves Safety-Related
technical contact listed below or the appropriate Office of Nuclear Reactor


Equip-ment Failures Caused by Faulted Indicating
Regulation (NRR) project manager.


Lamps 10/20/94 10/14/94 10/13/94 10/12/94 10/05/94 10/04/94 09/29/94 09/28/94 09/27/94 All 10 CFR Part 70 fuel cycle licensees.
Original signed by


All holders of OLs or CPs pressurized-water
Brian K. Grimes


reactors (PWRs).All U.S. Nuclear Regulatory
Brian K. Grimes, Director


Commission
Division of Project Support


Medical Licensees.
Office of Nuclear Reactor Regulation


===All fuel fabrication===
Technical contact:            D. Roberts, RII
facilities.


All'holders
(919) 362-0601 Attachment:
      List of Recently Issued NRC Information Notices


of OLs or CPs for pressurized
**    See previous concurrence


water reactors All holders of OLs or CPs for boiling water reactors (BWRs).All U.S. Nuclear Regulatory
Mamn dated Mav 27 1994 OFFICE      REGION II          REGION II      REGION II


Commission
NAME          DRoberts*        JRJohnson**    BBoger*
          DATE        08/18/94          05/27/94        08/19/94 OFFICE      EMEB:DE            C/EMEB:DE      D/DE:NRR


Medical Licensees.
NAME        JRajan*            RWessman*      BWSheron*
          nATF


All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs For nuclear power reactors.OL = Operating
Wu.-t L*, .I -
                        fl/19194 I    *-
                                        1 08/26/94
                                            _  , -    .


License CP = Construction
08/30/94
                                                            - ,            X


Permit
OFFICE      TECHED:RPB        OGCB:DORS:NRR    C/OGCB:DORS:NRR      D


: ..I IN 94-76 October 26, 1994 This information
NAME        JMain*            JBirmingham*      ELDoolittle*
          DATE        07/20/94          08/17/94        09/08/94              10t{/94 OFFICIAL DOCUMENT1 NAME:         V4-/0. IN


notice requires no specific action or written response.
IN 94-xx


If you have any questions
October xx, 1994 This information notice requires no specific action or written response. If


about the information
you have any questions about the information in this notice, please contact


in this notice, please contact technical
technical contact listed below or the appropriate Office of Nuclear Reactor


contact listed below or the appropriate
Regulation (NRR) project manager.


Office of Nuclear Reactor Regulation (NRR) project manager.Original signed by Brian K. Grimes Brian K. Grimes, Director Division of Project Support Office of Nuclear Reactor Regulation
Brian K. Grimes, Director


Technical
Division of Operating Reactor Support


contact: D. Roberts, RII (919) 362-0601 Attachment:
Office of Nuclear Reactor Regulation
List of Recently Issued NRC Information


Notices**See previous concurrence
Technical contact:      D. Roberts, R11
                        (919) 362-0601 Attachment:


Mamn dated Mav 27 1994 OFFICE REGION II REGION II REGION II NAME DRoberts*
===List of Recently Issued NRC Information Notices===
JRJohnson**
* See previous concurrence
BBoger*DATE 08/18/94 05/27/94 08/19/94 OFFICE EMEB:DE C/EMEB:DE


D/DE:NRR NAME JRajan* RWessman*  
** Memo dated May 27 1994 OFFICE   REGION II        REGION II            REGION II
BWSheron*nATF fl/19194 1 08/26/94 08/30/94 Wu.-t .I -I L*, *- _ , -., -X OFFICE TECHED:RPB


OGCB:DORS:NRR
NAME      DRoberts*        JRJohnson**          BBoger*
  DATE    , 08/18/94        [05/27/94          j08/19/94 OFFICE  [ EMEB:DE          C/EMEB:DE        ID/DE:NRR


C/OGCB:DORS:NRR
NAME      JRajan*          RWessman*        I BWSheron*
  DATE      08/22/94          08/26/94            08/30/94 OFFICE    TECHED:RPB      OGCB:DORS:NRR        C/OGCB:DORS:NRR  D/DORS:NRR


D NAME JMain* JBirmingham*  
NAME     JMain*           JBirmingham*         ELDoolittle*     BKGrimes
ELDoolittle*
DATE 07/20/94 08/17/94 09/08/94 10t{/94 OFFICIAL DOCUMENT1 NAME: V4-/0. IN


IN 94-xx October xx, 1994 This information
DATE


notice requires no specific action or written response.
vo


If you have any questions
, 07/20/94
                    *e-
                            108/17/94
                              -.-.


about the information
. o n Tl1 -^llrg


in this notice, please contact technical
, 09/08/94        1 10/  /94 A


contact listed below or the appropriate
UV ILIAL UULUMtNl  NAMt:    U:\UMF 14N.JLU


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
4t14L


===Reactor Support Office of Nuclear Reactor Regulation===
IN 94-xx
Technical


contact: D. Roberts, R11 (919) 362-0601 Attachment:
October xx, 1994 This information notice requires no specific action or written response. If
List of Recently Issued NRC Information


Notices* See previous concurrence
you have any questions about the information in this notice, please contact


** Memo dated May 27 1994 OFFICE REGION II REGION II REGION II NAME DRoberts*
technical contact listed below or the appropriate Office of Nuclear Reactor
JRJohnson**
BBoger*DATE , 08/18/94 [05/27/94 j 08/19/94 OFFICE [ EMEB:DE C/EMEB:DE


I D/DE:NRR NAME JRajan* RWessman*
Regulation (NRR) project manager.
I BWSheron*DATE 08/22/94 08/26/94 08/30/94 OFFICE TECHED:RPB


OGCB:DORS:NRR
Brian K. Grimes, Director


C/OGCB:DORS:NRR
Division of Operating Reactor Support


D/DORS:NRR
Office of Nuclear Reactor Regulation


NAME JMain* JBirmingham*
Technical contact:       D. Roberts, RII
ELDoolittle*
BKGrimes DATE , 07/20/94 1 08/17/94 , 09/08/94 1 10/ /94 vo .-.-. -^llrg *e- A o n Tl1 UV ILIAL UULUMtNl NAMt: U:\UMF 14N.JLU 4t14L


IN 94-xx October xx, 1994 This information
(919) 362-0601 Attachment:


notice requires no specific action or written response.
===List of Recently Issued NRC Information Notices===
* See previous concurrence


If you have any questions
** Memo dated May 27 1994 OFFICE    REGION II      lREGION II        REGION II


about the information
NAME      DRoberts*        JRJohnson**      BBoger*
  DATE      08/18/94        05/27/94        08/19/94 OFFICE    EMEB:DE          C/EMEB:DE      D/DE:NRR


in this notice, please contact technical
NAME      JRajan*          RWessman*      BWSheron*
  DATE


contact listed below or the appropriate
-      , ,
            08/22/94
                  , ,-,,
                              08/26/94
                                    *
                                              08/30/94
                                              _,
  OFFICE    TECHED:RPB      OGCB:DORS:NRR      C/OGCB:DORS:NRR  D/DORS:NRR


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
NAME      JMain*            JBirmingham*      ELDoolittle*      BKGrimes


===Reactor Support Office of Nuclear Reactor Regulation===
DATE    ,07/20/94        [08/17/94      109/08/94            110/  /94 U-ILIAL DULUMLNI NAM:        U:\FUMF 1N.JLU
Technical


contact: D. Roberts, RII (919) 362-0601 Attachment:
IN 94-xx
List of Recently Issued NRC Information


Notices* See previous concurrence
September xx, 1994 This information notice requires no specific action or written response. If


** Memo dated May 27 1994 OFFICE REGION II l REGION II REGION II NAME DRoberts*
you have any questions about the information in this notice, please contact
JRJohnson**
BBoger*DATE 08/18/94 05/27/94 08/19/94 OFFICE EMEB:DE C/EMEB:DE


D/DE:NRR NAME JRajan* RWessman*
technical contact listed below or the appropriate Office of Nuclear Reactor
BWSheron*DATE 08/22/94 08/26/94 08/30/94-,
* _, , , ,-,, OFFICE TECHED:RPB


OGCB:DORS:NRR
Regulation (NRR) project manager.


C/OGCB:DORS:NRR
Brian K. Grimes, Director


D/DORS:NRR
Division of Operating Reactor Support


NAME JMain* JBirmingham*
Office of Nuclear Reactor Regulation
ELDoolittle*
BKGrimes DATE ,07/20/94
[08/17/94
1 09/08/94 110/ /94 U-ILIAL DULUMLNI NAM: U:\FUMF 1N.JLU


IN 94-xx September
Technical contact:        D. Roberts, RII


xx, 1994 This information
(919) 362-0601 Attachment:
List of Recently Issued NRC Information Notices


notice requires no specific action or written response.
* See previous concurrence


If you have any questions
** MPm= dated May 27. 1994 OFFICE    REGION II          REGION II          REGION II


about the information
NAME      DRoberts*            JRJohnson**      BBoger*
  DATE    108/18/94          ,05/27/94            08/25/94 OFFICE      EMEB:DE            C/EMEB:DE        D/DE:NRR


in this notice, please contact technical
NAME      JRajan*              RWessman*        BWSheron&
  nATC


contact listed below or the appropriate
ulIL.    I


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
08/22/Q9
              -- I - -.


===Reactor Support Office of Nuclear Reactor Regulation===
nR/26/94        08/2_ v/94
Technical
                                                          .


contact: D. Roberts, RII (919) 362-0601 Attachment:
OFFICE      TECHED:RPB        OGCB:DORS:NRR      C      B:DORS:NRR D/DORS:NRR
List of Recently Issued NRC Information


Notices* See previous concurrence
NAME        JMain*           JBirmingham*l      Ek6V2 ittle        BKGrimes


** MPm= dated May 27. 1994 OFFICE REGION II REGION II REGION II NAME DRoberts*
DATE     107/20/94     -
JRJohnson**
                              -  108/17/94 -
BBoger*DATE 108/18/94  
                                - - .--        - -
,05/27/94  
                                                  j    P'Z' 94          08/ /94     '
08/25/94 OFFICE EMEB:DE C/EMEB:DE
  OF-FICIAL DOCUMEN      NAME:   b:\FUMr IN.VLb


D/DE:NRR NAME JRajan* RWessman*
. r
BWSheron&nATC 08/22/Q9 nR/26/94 08/2 v/94 ulIL. I --I --. _ .OFFICE TECHED:RPB


OGCB:DORS:NRR
IN 94-xx


C B:DORS:NRR
September xx, 1994 This information notice requires no specific action or written response. If


D/DORS:NRR
you have any questions about the information in this notice, please contact


NAME JMain* JBirmingham*l
technical contact listed below or the appropriate Office of Nuclear Reactor


Ek6V2 ittle BKGrimes DATE 1 07/20/94 -1 08/17/94 j P'Z' 94 08/ /94----- .---'OF-FICIAL
Regulation (NRR) project manager.


DOCUMEN NAME: b:\FUMr IN.VLb
Brian K. Grimes, Director


.r IN 94-xx September
Division of Operating Reactor Support


xx, 1994 This information
Office of Nuclear Reactor Regulation


notice requires no specific action or written response.
Technical contact:        D. Roberts, R11
                              (919) 362-0601 Attachment:
    List of Recently Issued NRC Information Notices


If you have any questions
* See previous concurrence


about the information
** Memo dated May 27 1994 OFFICE


in this notice, please contact technical
NAME


contact listed below or the appropriate
DATE


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
I


===Reactor Support Office of Nuclear Reactor Regulation===
l
Technical


contact: D. Roberts, R11 (919) 362-0601 Attachment:
REGION II
List of Recently Issued NRC Information


Notices* See previous concurrence
DRoberts*
                    08/18/94 REGION I1 JRJohnson**
                                  [05/27/94 REGION II


** Memo dated May 27 1994 OFFICE REGION II REGION I1 REGION II NAME I DRoberts*
BBoger*
JRJohnson**  
                                                      J08/19/94 OFFICE       EMEB:DE         C/EMEB:DE         IDI  iD IIRR
BBoger*DATE l 08/18/94 [05/27/94 J 08/19/94 OFFICE EMEB:DE C/EMEB:DE


ID I iD IIRR NAME JRajan* RWessman*  
NAME         JRajan*           RWessman*         IB S     on
I B S on W DATE 08/22/94 08/26/94 08/S6/94 OFFICE TECHED:RPB


OGCB:DORS:NRR
.t


C/OGCB:DORS:NRR
W


D/DORS:NRR
DATE          08/22/94        08/26/94          08/S6/94 OFFICE        TECHED:RPB      OGCB:DORS:NRR      C/OGCB:DORS:NRR  D/DORS:NRR


NAME JMain* JBirmingham*  
NAME         JMain*           JBirmingham*       ELDoolittle       BKGrimes
ELDoolittle


BKGrimes DATE 07/20/94 08/17/94 08/ /94 08/ /94 sors~a rvral~I.-  
DATE         07/20/94         08/17/94           08/   /94         08/   /94 sors~arvral~I.-   Plte     ^. nstl ti. of ^
Plte ^. nstl ti. of ^UMtILIAL UUUUMtNI NAML: b: \FUMr 1N.ULV
    UMtILIAL UUUUMtNI       NAML:   b: \FUMr 1N.ULV


IN 94-xx August xx, 1994 This information
IN 94-xx


notice requires no specific action or written response.
August xx, 1994 This information notice requires no specific action or written response. If


If you have any questions
you have any questions about the information in this notice, please contact


about the information
technical contact listed below or the appropriate Office of Nuclear Reactor


in this notice, please contact technical
Regulation (NRR) project manager.


contact listed below or the appropriate
Brian K. Grimes, Director


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Division of Operating Reactor Support


===Reactor Support Office of Nuclear Reactor Regulation===
Office of Nuclear Reactor Regulation
Technical


contact: D. Roberts, RII (919) 362-0601 Attachment:
Technical contact:     D. Roberts, RII
List of Recently Issued NRC Information


Notices* See previous concurrence
(919) 362-0601 Attachment:


** Memo dated May 27 1994 __41 OFFICE REGION II REGION II lEMED( C/EME l D/DE:NRR NAME DRoberts JRJohnson**
===List of Recently Issued NRC Information Notices===
JRajw" RWes ke rBWSheron DATE 08/ /94 05/27/94 0 8 /,/94 089f4/94 9 08/ /94 OFFICE 1 TECHED:RPB
  * See previous concurrence


J OGCB:DORS:NRR
** Memo dated May 27  1994          __41 OFFICE    REGION II  REGION II    lEMED(        C/EME        l D/DE:NRR


C/OGCB:DORS:NRR
NAME      DRoberts    JRJohnson**  JRajw"        RWes  ke      rBWSheron


D/DORS:NRR
DATE      08/  /94    05/27/94      08/,/94            9
                                                    089f4/94      08/    /94 OFFICE  1 TECHED:RPB    JOGCB:DORS:NRR  C/OGCB:DORS:NRR  D/DORS:NRR


NAME l JMain* JBimnghim*  
NAME   l JMain*         JBimnghim* It ELDoolittle       BKGrimes
It ELDoolittle


BKGrimes DATE l 07/20/94 l 08/17/94 08/ /94 08/ /94 OFFICIAL DOCUMENT NAME: G:\PUMPIN.JLB}}
DATE   l 07/20/94     l 08/17/94       08/ /94         08/   /94 OFFICIAL DOCUMENT NAME: G:\PUMPIN.JLB}}


{{Information notice-Nav}}
{{Information notice-Nav}}

Latest revision as of 04:29, 24 November 2019

Recent Failures of Charging/Safety Injection Pump Shafts
ML031060430
Person / Time
Site: Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant  Entergy icon.png
Issue date: 10/26/1994
From: Grimes B
Office of Nuclear Reactor Regulation
To:
References
IN-94-076, NUDOCS 9410200153
Download: ML031060430 (12)
v • d • e


4 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 October 26, 1994 NRC INFORMATION NOTICE 94-76: RECENT FAILURES OF CHARGING/SAFETY INJECTION

PUMP SHAFTS

Addressees

All holders of operating licenses or construction permits for pressurized

water rekctors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information

notice (IN)to alert addressees to recent failures of charging/safety

injection pump shafts at facilities designed by the Westinghouse Electric

Corporation (Westinghouse). 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.

Background 4 At Westinghouse-designed facilities, charging/safety injection pumps have

4 ction flow to the reactor coolant

three funct ons: (1) to deliver seal iri

pumps, (2) .o eliver makeup water flcv ) the reactor coolant system, and

(3) to deliver high head safety injection and recirculation flow to the

reactor coolant system during and after a loss-of-coolant accident. During

normal operation, one of two, or in some cases, one of three pumps is always

in operation to deliver seal injection and makeup water flow. The loss of an

inservice charging/safety injection pump creates a condition that may

challenge reactor coolant pump seal integrity and, if makeup water flow is not

restored in a timely manner, can result in a loss of coolant inventory.

On February 29, 1980, the NRC issued IN 80-07, "Pump Shaft Fatigue Cracking,"

to alert recipients to failures of charging/safety injection pump shafts that

occurred during the 1970s. All of the charging/safety injection pump shafts

addressed in that notice were procured by Westinghouse from the Pacific Pump

Division of Dresser Industries (now Ingersoll-Dresser Pump Co). Actions taken

at that time to correct the problem included design modifications, changes in

the heat treatment of the shaft material, and the use of formed cutting tools

during fabrication. Also, abnormal operation of the pumps such as operation

with a partial or complete loss of fluid or with high vibration present was

found to be a significant contributor to the shaft failures. The Westinghouse

Nuclear Service Division issued Technical Bulletins TB-77-", TB-78-1, and

TB-79-6, to provide guidance on vibration monitoring, operation and

maintenance of the pumps, and allowable vibration amplitude limits.

9410200153 4 gfokC 4 On P4R C AI 0+ic4V

Iae

vJ

IN 94-76 October 26, 1994 Recent events indicate that failures of charging/safety injection pump shafts

continue to be a problem.

Description of Circumstances

Sequoyah Unit 1

On February 18, 1991, plant operators for Sequoyah Unit 1 received indications

of decreasing flow and increasing motor current on charging pump IB-B. When

efforts to restore full flow failed, they declared the pump inoperable and

began shutting down the reactor as required by plant technical specifications.

Charging pump lB-B had been in operation for several months and had shown no

previous signs of degradation. The licensee disassembled the pump, found

heavy wear on the impeller shoulders and the balance drum, and found a

280-degree crack in the shaft near the 11th stage impeller. Westinghouse

analyzed the shaft and determined that the crack had been in the shaft for

several months (possibly years) and that the rotating element was of the

improved type referred to in IN 80-07. The licensee replaced +he rotating

element and, after testing the pump successfully, returned the pump to

service. [Licensee Event Report (LER) 50-327/91-003]

Callaway

On February 2, 1992, the Union Electric Company Callaway Plant was at power

and charging pump B was in service to support operations. Plant operators

received indications of zero flow in the charging header and at the reactor

coolant pump seal. The operators placed charging pump A iA service to restore

normal flow, and pump B tripped. Plant personnel inspected pump B and found

that the shaft had sheared on the outboard end between the balance drum lock

nut an, balance drum mating area. le licensee documented the failure in

Suggestion Occurrence Solution 92-10 and replaced the failed shaft.

Shearon Harris

On March 18, 1993, operators at the Shearon Harris plant received indications

of a shaft failure on charging/safety injection pump B. The indications were

high motor current, low charging flow, and low pump discharge pressure. The

operators secured pump B from service and placed pump A in service. Plant

personnel uncoupled the pump from the motor and found that the pump shaft had

sheared under the balancing drum lock nut. This was the same location as in

three failures that occurred in the 1970s. (LER 50-400/93-005)

D.C. Cook Unit 2

In July 1993, at D.C. Cook Unit 2, a charging pump failed a surveillance test

when it could not deliver the required 454 liters [120 gallons] per minute.

The rotating element in that pump had been installed in 1987. The licensee

disassembled the pump and found a 10 centimeter [4 inch!, 180 degree

circumferential crack through the number 9 impeller shaft keyway. Smaller

cracks were found in two other impeller keyway areas. (LER 50-316/93-006)

IN 94-76 October 26, 1994 Braidwood Unit 1 and Sequoyah Unit 2 The NRC staff has received information on two other recent failures of

charging/safety injection pump shafts: (1) on September 15, 1993, at the

Braidwood Nuclear Station Unit 1 (Braidwood), a charging/safety injection pump

shaft sheared between the 10th and 11th stage impellers, and (2) on

February 7, 1994, at Sequoyah Unit 2, a charging\safety injection pump shaft

failed, resulting in a reactor shutdown as required by plant technical

specifications. The licensee for Braidwood replaced the pump shaft and

documented the failure on Problem Investigation Report 456-200-93-03600. The

licensee for Sequoyah reported that the affected pump had not exhibited any

indication of degradation before the shaft failure and that, similar to many

of the other shaft failures, the shaft had failed near the location of the

balancipng drum lock nut. (LER 50-328/94-002)

Discussion

Charging/safety injection pumps are important for normal plant operation and

for core cooling during accidents such as a small break loss-of-coolant

accident. Fcr most of the failure events described above, determination of

the root cause of the failure was inconclusive. However, the operational

histories of many of the failed shafts showed that they had been operated with

void formation, gas entrainment, or other abnormal conditions within a few

years of the failure. Operation of the pumps under these conditions may have

caused or contributed to the later failure of the shafts. Avoiding operation

of charging pumps under abnormal conditions and maintaining vibration levels

within manufacturer recommendations may increase pump reliability. To

increase the benefit of predictive maintenance programs, Wbstinghouse

recommends that pump vibrations be monitored at least monthly; preferably, every two weeks. This is more frequent than is required by Section XI of the

ASME B iler and Pressure Vessel Code. V'stinghouse will provide recommended

vibration limits upon request.

Industry experience in detecting shaft failures in pumps such as the reactor

coolant pump and the recirculation pump is relevant to monitoring programs of

charging/safety injection pumps because the precursors to shaft failure are

similar. For those pumps, monitoring phase angles as well as monitoring

vibration amplitude is considered to be important in detecting shaft

degradation. These data are routinely trended by some licensees for detection

of impending shaft failures.

A description of the analyses and conclusions for some of the above events

follows:

Westinghouse evaluated seven possible root causes for the shaft failure at

Callaway, including material defects, design flaws, errors in fabrication or

processing, assembly or installation defects, off-design or unintended service

conditions, maintenance deficiencies, and improper operation. Westinghouse

concluded that the shaft failure was most likely the result of a 1986 event in

which the pump had experienced a loss of suction water flow for approximately

seven minutes. The loss of suction flow increased the vapor-to-liquid ratio

in the pump and caused a dynamic imbalance. Events of this type could cause

K>~

IN 94-76 October 26, 1994 immediate pump failure or cause cyclic fatigue damage that could lead to

premature shaft failure at a later date.

A gas entrainment event that occurred on August 20, 1990, was determined to be

the probable cause of the shaft failure at Sequoyah Unit 2. Problems caused

by gas entrainment are discussed in NRC Information Notice 88-23, "Potential

for Gas Binding of High-Pressure Safety Injection Pumps During a Design Basis

Accident," and its supplements.

Westinghouse considers an operational phenomenon, such as gas entrainment, may

have led to the shaft failure at Shearon Harris, although the licensee found

no evidence of gas pockets in the charging system. In May 1991 (two years

before-the shaft failure), the licensee reported to the NRC that the charging

system had been in a degraded condition during the previous operating cycle.

An NRC Special Inspection Team reviewed the event and determined that several

water hammer events could have occurred in the system as a result of

weaknesses in the design of the alternate minimum flow system. The NRC issued

IN 92-61, "Loss of High Head Safety Injection," and its supplement regarding

that event. Another concern at Shearon Harris was the fact that the A and B

charging/safety injection pumps are alternated at approximately 2-week

intervals. Therefore, each pump is started about 25 to 30 times each year.

Westinghouse believes the high number of starts also could contribute to early

shaft failure. Problems associated with excessive pump starts include galled

wear rings, increased vibration, and decreased pump performance. However, Westinghouse concluded that the available data were insufficient to directly

link the failure of the shaft to the high number of pump starts.

Although Westinghouse could not conclusively determine the root cause of the

shaft failure at Shearon Harris, West 'nghouse made recommendations which could

help pre-ent or detect impendine shaf fa;lures. Westinghou- suggested that

the liceasee conduct a detailed review, of the possibility that gas could

become entrained in the charging pump suction piping and the cross connczts to

other systems. Westinghouse also recommended that, when the rotating element

of the pump is replaced, consideration be given to installing the latest shaft

design which has an improved one-piece balance drum lock nut. Westinghouse

included recommendations for vibration monitoring in Westinghouse Technical

Bulletin TB-79-6. Westinghouse has not specified a limitation on the number

of pump starts but recommends that pump starts be minimized to maintain pump

reliability.

In addition to the industry actions described above, Westinghouse and the

Westinghouse Owners Group (WOG) are implementing a program to address these

pump shaft failures. The program includes: (1) a survey of WOG member

utilities for pump service operating history data, (2) a pump design review, and (3) a shaft material enhancement evaluation. The program is intended to

identify any weaknesses in design, maintenance, or operation of the pumps in

order to improve shaft reliability.

I S :. .

. I

IN 94-76 October 26, 1994 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Project Support

Office of Nuclear Reactor Regulation

Technical contact: D. Roberts, RII

(919) 362-0601 Attachment:

List of Recently Issued NRC Information Notices

daret4s C'

Attachment

IN 94-76 October 26, 1994 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

93-60, Reporting Fuel Cycle 10/20/94 All 10 CFR Part 70

Supp. 1 and Materials Events to fuel cycle licensees.

the NRC Operations Center

94-75 Minimum Temperature 10/14/94 All holders of OLs or CPs

for Criticality pressurized-water reactors

(PWRs).

94-74 Facility Management 10/13/94 All U.S. Nuclear Regulatory

Responsibilities for Commission Medical

Purchased or Contracted Licensees.

Services for Radiation

Therapy Programs

94-73 Clarification of Critical- 10/12/94 All fuel fabrication

ity Reporting Criteria facilities.

94-72 Increased Control Rod 10/05/94 All'holders of OLs or CPs

Drop Time from Crud for pressurized water

Buildup reactors

94-71 Degradation of Scram 10/04/94 All holders of OLs or CPs

Solenoid Pilot Valve for boiling water reactors

Pressure and Exhaust (BWRs).

Diaphragms

94-70 Issues Associated with Use 09/29/94 All U.S. Nuclear Regulatory

of Strontium-89 and Other Commission Medical

Beta Emitting Radiopharma- Licensees.

ceuticals

94-69 Potential Inadequacies 09/28/94 All holders of OLs or CPs

in the Prediction of Torque for nuclear power reactors.

Requirements for and Torque

Output of Motor-Operated

Butterfly Valves

94-68 Safety-Related Equip- 09/27/94 All holders of OLs or CPs

ment Failures Caused by For nuclear power reactors.

Faulted Indicating Lamps

OL = Operating License

CP = Construction Permit

. . I

IN 94-76 October 26, 1994 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

technical contact 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 Project Support

Office of Nuclear Reactor Regulation

Technical contact: D. Roberts, RII

(919) 362-0601 Attachment:

List of Recently Issued NRC Information Notices

    • See previous concurrence

Mamn dated Mav 27 1994 OFFICE REGION II REGION II REGION II

NAME DRoberts* JRJohnson** BBoger*

DATE 08/18/94 05/27/94 08/19/94 OFFICE EMEB:DE C/EMEB:DE D/DE:NRR

NAME JRajan* RWessman* BWSheron*

nATF

Wu.-t L*, .I -

fl/19194 I *-

1 08/26/94

_ , - .

08/30/94

- , X

OFFICE TECHED:RPB OGCB:DORS:NRR C/OGCB:DORS:NRR D

NAME JMain* JBirmingham* ELDoolittle*

DATE 07/20/94 08/17/94 09/08/94 10t{/94 OFFICIAL DOCUMENT1 NAME: V4-/0. IN

IN 94-xx

October 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

technical contact 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 contact: D. Roberts, R11

(919) 362-0601 Attachment:

List of Recently Issued NRC Information Notices

  • See previous concurrence
    • Memo dated May 27 1994 OFFICE REGION II REGION II REGION II

NAME DRoberts* JRJohnson** BBoger*

DATE , 08/18/94 [05/27/94 j08/19/94 OFFICE [ EMEB:DE C/EMEB:DE ID/DE:NRR

NAME JRajan* RWessman* I BWSheron*

DATE 08/22/94 08/26/94 08/30/94 OFFICE TECHED:RPB OGCB:DORS:NRR C/OGCB:DORS:NRR D/DORS:NRR

NAME JMain* JBirmingham* ELDoolittle* BKGrimes

DATE

vo

, 07/20/94

  • e-

108/17/94

-.-.

. o n Tl1 -^llrg

, 09/08/94 1 10/ /94 A

UV ILIAL UULUMtNl NAMt: U:\UMF 14N.JLU

4t14L

IN 94-xx

October 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

technical contact 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 contact: D. Roberts, RII

(919) 362-0601 Attachment:

List of Recently Issued NRC Information Notices

  • See previous concurrence
    • Memo dated May 27 1994 OFFICE REGION II lREGION II REGION II

NAME DRoberts* JRJohnson** BBoger*

DATE 08/18/94 05/27/94 08/19/94 OFFICE EMEB:DE C/EMEB:DE D/DE:NRR

NAME JRajan* RWessman* BWSheron*

DATE

- , ,

08/22/94

, ,-,,

08/26/94

08/30/94

_,

OFFICE TECHED:RPB OGCB:DORS:NRR C/OGCB:DORS:NRR D/DORS:NRR

NAME JMain* JBirmingham* ELDoolittle* BKGrimes

DATE ,07/20/94 [08/17/94 109/08/94 110/ /94 U-ILIAL DULUMLNI NAM: U:\FUMF 1N.JLU

IN 94-xx

September 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

technical contact 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 contact: D. Roberts, RII

(919) 362-0601 Attachment:

List of Recently Issued NRC Information Notices

  • See previous concurrence
    • MPm= dated May 27. 1994 OFFICE REGION II REGION II REGION II

NAME DRoberts* JRJohnson** BBoger*

DATE 108/18/94 ,05/27/94 08/25/94 OFFICE EMEB:DE C/EMEB:DE D/DE:NRR

NAME JRajan* RWessman* BWSheron&

nATC

ulIL. I

08/22/Q9

-- I - -.

nR/26/94 08/2_ v/94

.

OFFICE TECHED:RPB OGCB:DORS:NRR C B:DORS:NRR D/DORS:NRR

NAME JMain* JBirmingham*l Ek6V2 ittle BKGrimes

DATE 107/20/94 -

- 108/17/94 -

- - .-- - -

j P'Z' 94 08/ /94 '

OF-FICIAL DOCUMEN NAME: b:\FUMr IN.VLb

. r

IN 94-xx

September 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

technical contact 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 contact: D. Roberts, R11

(919) 362-0601 Attachment:

List of Recently Issued NRC Information Notices

  • See previous concurrence
    • Memo dated May 27 1994 OFFICE

NAME

DATE

I

l

REGION II

DRoberts*

08/18/94 REGION I1 JRJohnson**

[05/27/94 REGION II

BBoger*

J08/19/94 OFFICE EMEB:DE C/EMEB:DE IDI iD IIRR

NAME JRajan* RWessman* IB S on

.t

W

DATE 08/22/94 08/26/94 08/S6/94 OFFICE TECHED:RPB OGCB:DORS:NRR C/OGCB:DORS:NRR D/DORS:NRR

NAME JMain* JBirmingham* ELDoolittle BKGrimes

DATE 07/20/94 08/17/94 08/ /94 08/ /94 sors~arvral~I.- Plte ^. nstl ti. of ^

UMtILIAL UUUUMtNI NAML: b: \FUMr 1N.ULV

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

technical contact 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 contact: D. Roberts, RII

(919) 362-0601 Attachment:

List of Recently Issued NRC Information Notices

  • See previous concurrence
    • Memo dated May 27 1994 __41 OFFICE REGION II REGION II lEMED( C/EME l D/DE:NRR

NAME DRoberts JRJohnson** JRajw" RWes ke rBWSheron

DATE 08/ /94 05/27/94 08/,/94 9

089f4/94 08/ /94 OFFICE 1 TECHED:RPB JOGCB:DORS:NRR C/OGCB:DORS:NRR D/DORS:NRR

NAME l JMain* JBimnghim* It ELDoolittle BKGrimes

DATE l 07/20/94 l 08/17/94 08/ /94 08/ /94 OFFICIAL DOCUMENT NAME: G:\PUMPIN.JLB


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