United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 91-27: Incorrect Rotation of Positive Displacement Pump

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF NUCLEAR REACTOR REGULATION
                           WASHINGTON, D.C.  20555

                               April 10, 1991


Information Notice No. 91-27:  INCORRECT ROTATION OF POSITIVE 
                                   DISPLACEMENT PUMP 


Addressees:

All holders of operating licenses or construction permits for nuclear power 
reactors.

Purpose:

This information notice is intended to alert addressees to the potential 
existence of positive displacement pumps with reverse rotation caused by 
incorrect wiring.  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 do not constitute NRC requirements; therefore, no 
specific action or written response is required.

Description of Circumstances:

On February 15, 1990, one of the two positive displacement pumps in the 
standby liquid control system at Brunswick Unit 2 was observed rotating in 
the reverse direction.  This discovery was made after maintenance; however, 
nothing in the maintenance procedure could have affected the rotational 
direction of the pump, and the condition had apparently existed for some 
indeterminate period of time.  During the resulting investigation, Brunswick 
personnel discovered that two electrical leads had been interchanged in the 
motor control center that fed power to the standby liquid control pump 
causing the three-phase pump motor to rotate in the reverse direction.  
Although Brunswick personnel routinely made rotational checks following pump 
maintenance, apparently in this case the maintenance personnel mistakenly 
believed that the existing direction of rotation was correct.

Discussion:

The standby liquid control system includes positive displacement 
reciprocating piston pumps.  The direction of rotation has no immediate 
effect on the performance of these pumps.  However, the pump internal drive 
train lubrication system does depend upon the correct direction of pump 
rotation to fill an elevated reservoir which then drains oil over the drive 
pistons.  Oil splash would provide some lubrication when the pump is rotated 
in the reverse direction.  According to the pump vendor, Union Pump, the 
splash effect could supply 

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                                                            April 10, 1991
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sufficient lubrication for short-term operation, particularly for the slower 
speed pumps used in the standby liquid control systems.  Consequently, these 
pumps, which are operated for approximately 15 minutes per month for 
surveillance testing, might not show any adverse effects for some time.  In 
addition to depriving the pump of adequate lubrication, reverse operation 
could cause excessive wear to the pump seals and detectable oil leakage.  

Positive displacement pumps are used in the standby liquid control system at 
all boiling water reactors and are also used in the charging system at some 
pressurized water reactors.  Both of these applications involve important 
safety systems that might be required to operate for extended periods of 
time in the event of an accident.  In keeping with this, Brunswick personnel 
have labeled the standby liquid control system pumps to indicate their 
correct direction of rotation.  Careful visual rotational checks, included 
with the pump surveillance procedures, are important in ensuring that 
positive displacement pumps will continue to operate correctly.

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:  Donald C Kirkpatrick, NRR
                     (301) 492-1849

                     Ted Cintula, AEOD
                     (301) 492-4493


Attachment:  List of Recently Issued NRC Information Notices


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