United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 88-87: Pump Wear and Foreign Objects in Plant Piping Systems

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

                                November 16, 1988


Information Notice No. 88-87:  PUMP WEAR AND FOREIGN OBJECTS IN PLANT 
                                   PIPING SYSTEMS


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 
flow reduction resulting from pump wear and foreign objects in plant piping 
systems.  It is expected that recipients will review the information for ap-
plicability 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:

The NRC has received three licensee event reports (LERs) (50-281/88-004, 
50-281/88-010, and 50-280/88-017) related to pump wear and foreign objects in 
plant piping systems that could affect the ability of plant safety systems to 
perform their functions during a design-basis accident.  These events were 
reported by Virginia Electric and Power Company's Surry Nuclear Power Station.

On March 27, 1988, during a manual reactor trip on Surry Unit 2, the auxiliary
feedwater (AFW) flow to the "A" steam generator (S/G) was noted to be low.  
Extensive valve testing and inspections at the time did not locate the cause 
of the low flow (LER 50-281/88-004).

On May 16, 1988, Surry Unit 2, while at 100 percent power, experienced a 
reactor trip as a result of S/G low-low level.  Following the reactor trip, 
the AFW flow to the "A" S/G was noted lower than expected.  The flow was 
observed to be 227 gallons per minute (gpm) compared with 325 gpm for the "B" 
and "C" S/G.  Additional testing of the AFW flow to the "A" S/G indicated that 
a partial blockage existed in the flowpath.

The reduced AFW flow to the "A" S/G was due to a metallic object partially 
blocking the cavitating venturi in the "A" AFW line.  The metal piece was 
determined to be from the channel ring vane on the "B" motor-driven AFW pump. 
Subsequent visual inspection using fiber optics located two metal pieces.  One
was located upstream of the cavitating venturi in the line to the "A" S/G and 
a second was at a flow orifice in the "C" S/G AFW line.  Inspection of the 

8811090284
.                                                            IN 88-87 
                                                            November 16, 1988 
                                                            Page 2 of 2 


three AFW pumps revealed that one chip was missing from a channel ring vane 
tip in the "A" motor-driven AFW pump, eight small pieces were broken off from 
the channel ring vane tips in the "B" motor-driven AFW pump, and numerous 
chips were missing from the outer vane ends in the turbine-driven AFW pump.  
In addition, a nondestructive inspection revealed several cracked channel ring
vanes in the turbine-driven AFW pump.

The two pieces retrieved from the piping were verified to have come from the 
"B" motor-driven AFW pump.  Extensive inspection of the AFW system piping did 
not locate the other small pieces missing from the AFW pumps (LER 
50-281/88-010).

On June 6, 1988, Surry Units 1 and 2 were in cold shutdown following a special
test run of the Unit 1 inside recirculation spray pump (IRSP), and foreign 
material was found in the temporary discharge cone strainer.  The material 
consisted of cap screws, a swagelock cap, nuts, weld wire, and other objects. 
As a result of this finding and the imminent return to power by Unit 2, the 
Unit 2 recirculation spray pump sumps were inspected.  This area includes the 
pump suctions for the IRSPs, the outside recirculation spray pumps, and the 
low-head safety-injection pumps.  This inspection, utilizing fiber optics, 
observed nuts, bolts, wire, metal and wood pieces, and other material in the 
sump.  These foreign objects were subsequently removed (LER 50-280/88-017). 

Discussion:

The events described above illustrate the potential for loss or significant 
reduction of flow from safety-related pumps as a consequence of pump wear and 
foreign objects in the plant piping systems.  The objects in the AFW system 
significantly reduced the flow to the affected S/G.  Lack of appropriate pump 
internal inspections may have contributed to the failure to identify the 
problem with the pump channel ring vanes earlier.  The foreign objects found 
in the safety-related system piping resulted from inadequate foreign material 
exclusion from sump wells and/or inadequate inspection after maintenance 
activities in the past. 

No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact 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: W. Holland, Region II
                    (804) 357-2101

                    L. Nicholson, Region II
                    (804) 357-2101

Attachment:  List of Recently Issued NRC Information Notices
.                                                            Attachment 
                                                            IN 88-87 
                                                            November 16, 1988 
                                                            Page 1 of 1

                             LIST OF RECENTLY ISSUED
                             NRC INFORMATION NOTICES
_____________________________________________________________________________
Information                                  Date of 
Notice No._____Subject_______________________Issuance_______Issued to________

86-106,        Feedwater Line Break          11/10/88       All holders of OLs
Supp. 3                                                     or CPs for nuclear
                                                            power reactors. 

88-86          Operating with Multiple       10/21/88       All holders of OLs
               Grounds in Direct Current                    or CPs for nuclear
               Distribution Systems                         power reactors. 

88-85          Broken Retaining Block        10/14/88       All holders of OLs
               Studs on Anchor Darling                      or CPs for nuclear
               Check Valves                                 power reactors. 

88-84          Defective Motor Shaft         10/20/88       All holders of OLs
               Keys in Limitorque Motor                     or CPs for nuclear
               Actuators                                    power reactors. 

88-83          Inadequate Testing of Relay   10/19/88       All holders of OLs
               Contacts in Safety-Related                   or CPs for nuclear
               Logic Systems                                power reactors. 

88-82          Torus Shells with Corrosion   10/14/88       All holders of OLs
               and Degraded Coatings in                     or CPs for BWRs. 
               BWR Containments 

88-81          Failure of Amp Window         10/7/88        All holders of OLs
               Indent Kynar Splices                         or CPs for nuclear
               and Thomas and Betts                         power, test, and 
               Nylon Wire Caps During                       research reactors.
               Environmental Quali-
               fication Testing 

88-80          Unexpected Piping Movement    10/7/88        All holders of OLs
               Attributed to Thermal                        or CPs for PWRs. 
               Stratification 

88-79          Misuse of Flashing Lights     l0/7/88        All holders of OLs
               for High Radiation Area                      or CPs for nuclear
               Controls                                     power reactors. 

_____________________________________________________________________________
OL = Operating License
CP = Construction Permit
Page Last Reviewed/Updated Tuesday, November 12, 2013