United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 88-70: Check Valve Inservice Testing Program Deficiencies

                                  UNITED STATES
                          NUCLEAR REGULATORY COMMISSION
                             WASHINGTON, D.C.  20555

                                 August 29, 1988



All holders of operating licenses or construction permits for nuclear power 


This information notice is being provided to alert addressees to potential 
problems uncovered by recent inspections of the check valve inservice testing 
(IST) programs at Wm. B. McGuire Nuclear Station, Units 1 and 2 (McGuire), 
Zion Nuclear Plant, Units 1 and 2 (Zion), and  R. E. Ginna Nuclear Power Plant
(Ginna).  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.


During November 30 to December 11, 1987, and January 4 to 8, 1988, a 
diagnostic inspection was performed at McGuire by a team led by personnel from
the Office for Analysis and Evaluation of Operational Data.  The major 
inspection findings pertaining to check valves were as follows: 

     (1)  Check valves located in the steam supply line to the turbine-driven 
          auxiliary feedwater (AFW) pump were not included in the McGuire IST 

     (2)  AFW system valves, which include both isolation and check valves 
          used to isolate the three sources of non-safety-related water to the
          AFW system, were not included in the McGuire IST program.  The 
          non-safety-related water sources include the hot well, the AFW 
          condensate storage tank, and the upper surge tanks. 

     (3)  No reverse-flow operability tests were being performed on check 
          valves other than those valves used for containment isolation and 
          reactor coolant system pressure boundary isolation.  This omission 

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          disregards Section XI of the ASME Boiler and Pressure Vessel Code 
          (ASME code), which requires testing in the open or closed position 
          (or both), as necessary, to verify the valve's safety function.  
          Consequently, undetected check valve failures could have existed 
          because of the lack of testing.

From September 14 to 18, 1987, an inspection team performed a special check 
valve inspection at Zion.  Many check valves in the AFW system, the component 
cooling water system, the chemical and volume control system, the diesel 
cooling water system, and the feedwater system were found to be not included 
in the IST program. Other major inspection findings were as follows:  

     (1)  Pressure isolation valves (PIVs) were not being adequately tested 
          individually as required by an NRC confirmatory order issued 
          February 29, 1980. 

     (2)  Valve testing did not ensure that all safety functions could be 

     (3)  Test procedures did not result in valid tests of all valves listed 
          as having been tested in accordance with the ASME code. 

     (4)  Valves failing leak-rate testing were not being repaired before re-
          start, contrary to commitments made in a June 11, 1987, response to 
          Generic Letter 87-06, "Periodic Verification of Leak-Tight Integrity
          of Pressure Isolation Valves (PIVs)."  

This inspection was followed by a special safety inspection on PIVs at Zion, 
which was performed between September 21 and October 26, 1987.  Major in-
spection findings were as follows: 

     (1)  Zion procedures did not provide adequate leak tests for certain 
          check valves in the safety injection system.

     (2)  Test procedures failed, in some cases, to provide a viable means to 
          determine the actual leak rate.  In other cases, a viable means 
          existed, but the licensee failed to calibrate the measuring in-

     (3)  Leaking valves had been left unrepaired since mid-1986. 
As a result of this inspection, the NRC issued a Level III violation to the 
Commonwealth Edison Company on January 4, 1988.

From May 16 to 20, 1988, an inspection team performed a special announced 
inspection on the IST activities at Ginna.  The major inspection findings 
pertaining to check valves were as follows: 

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     (1)  Certain check valves in the main feedwater (MFW) system and in the 
          turbine-driven AFW pump steam supply lines were not included in the 
          Ginna IST program. 

     (2)  A check valve in the steam supply line to the turbine-driven AFW 
          pump was found by the inspection team to have serious binding and to
          be in need of repair.  If this valve had been undergoing full-stroke
          exercising and reverse-flow closure testing, this failure would not 
          have gone undetected. 

     (3)  Numerous check valves in the service water system, the containment 
          spray line, the residual heat removal system, the safety injection 
          (SI) system, and the SI accumulator discharge line were not being 
          full-stroke exercised. 

     (4)  Certain check valves in these systems were not being tested for 
          reverse-flow closure capability in accordance with the ASME code 

As a result of this inspection, the NRC issued a Level III violation to the 
Rochester Gas and Electric Company on July 27, 1988.

Similar problems were also discovered at the San Onofre Nuclear Generating 
Station Unit 1 (SONGS 1) when a serious water hammer occurred on November 21, 
1985 in the MFW system.  This water hammer event occurred after a reactor trip
because of injection of auxiliary feedwater into a main feedwater line that 
had partially drained through multiple inoperable check valves.  Information 
Notice 86-01, "Failure of Main Feedwater Check Valves Causes Loss of Feedwater
System Integrity and Water-Hammer Damage," was issued to call attention to 
this incident. 


The common findings from these inspections are as follows:

     (1)  Not all safety-related check valves have been identified and 
          included in the IST programs. 

     (2)  When check valves are included in the program, the valves are not 
          always tested in a way that verifies their ability to perform their 
          safety-related functions.  

These findings point out the importance of verifying the completeness of the 
list of components included in IST programs and of ensuring the adequacy of 
the actual testing being performed when developing an IST program.  Not taking
these two factors into account could result in undetected serious degradation 
of components, as happened at SONGS 1 and Ginna.  The incident at SONGS 1 is 
an example of the possible consequences of such degradation.
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No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical 
contact listed below or the Regional Administrator of the appropriate regional

                              Charles E. Rossi, Director
                              Division of Operational Events Assessment
                              Office of Nuclear Reactor Regulation

Technical Contact:  Horace K. Shaw, NRR
                    (301) 492-0906 

Attachment:  List of Recently Issued NRC Information Notices
.                                                            Attachment 
                                                            IN 88-70 
                                                            August 29, 1988 
                                                            Page 1 of 1

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

88-69          Movable Contact Finger        8/19/88        All holders of OLs 
               Binding in HFA Relays                        or CPs for nuclear
               Manufactured by General                      power reactors. 
               Electric (GE) 

88-48,         Licensee Report of Defective  8/24/88        All holders of OLs
Supplement 1   Refurbished Valves                           or CPs for nuclear
                                                            power reactors. 

88-68          Setpoint Testing of Pres-     8/22/88        All holders of OLs
               surizer Safety Valves with                   or CPs for nuclear
               Filled Loop Seals Using                      power reactors. 
               Hydraulic Assist Devices 

88-67          PWR Auxiliary Feedwater Pump  8/22/88        All holders of OLs
               Turbine Overspeed Trip                       or CPs for nuclear
               Failure                                      power reactors. 

88-66          Industrial Radiography        8/22/88        All NRC industrial
               Inspection and Enforcement                   radiography 

88-65          Inadvertent Drainages of      8/18/88        All holders of OLs
               Spent Fuel Pools                             or CPs for nuclear
                                                            power reactors and
                                                            fuel storage 

88-64          Reporting Fires in Nuclear    8/18/88        All holders of OLs
               Process Systems at Nuclear                   or CPs for nuclear
               Power Plants                                 power reactors. 

88-63          High Radiation Hazards        8/15/88        All holders of OLs
               from Irradiated Incore                       or CPs for nuclear
               Detectors and Cables                         power reactors, 
                                                            research reactors 
                                                            and test reactors.

88-62          Recent Findings Concerning    8/12/88        All holders of NRC
               Implementation of Quality                    quality assurance 
               Assurance Programs by                        program approval 
               Suppliers of Transport                       for radioactive 
               Packages                                     material packages.

OL = Operating License
CP = Construction Permit 
Page Last Reviewed/Updated Friday, May 22, 2015