United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 81-30: Velan Swing Check Valves

                                                             SSINS No. 6835 
                                                             Accession No.: 
                                                             8107230027    
                                                             IN 81-30      

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C. 20555
                                     
                             September 28, 1981

Information Notice No. 81-30:   VELAN SWING CHECK VALVES 

Description of Circumstances: 

Recent occurrences with Velan swing check valves are described below. 

1.   On June 30, 1981, Public Service Electric & Gas Company reported (LER 
     81-035/01T) that on June 6, 1981, while a leak in the bonnet of a swing
     check valve in the steam supply to the turbine driven auxiliary 
     feedwater pump at Salem Generating Station, Unit 2, was being repaired,
     the valve was found to be internally damaged. The valve is a Velan 
     6-in. swing check valve (Type B14-2114 B-2TS). 

     The valve disk stud had broken and the valve disk was in the bottom of 
     the valve body. The valve also had cracks in the disk, cracked 
     bushings, a warped hinge pin, and all hinge pin holes were elongated. 

     The licensee inspected the corresponding swing check valve in the other
     steam supply line and discovered similar damage. An inspection of the 
     corresponding swing check valves on Unit 1 also revealed similar damage
     (LER 81-059/01T). 

     The licensee plans to radiologically examine the valves monthly until 
     a reason for the damage can be determined. 

2.   On July 31, 1981, Wisconsin Electric Power Company reported (LER 
     81-010/01T-O) that on July 14, 1981, while a check valve leakage test 
     at the Point Beach Nuclear Plant, Unit 1, was being performed, the 
     check valves closest to the reactor coolant system in the low head 
     safety injection lines were found to be leaking more than allowed by 
     the leakage acceptance criteria. The valves are Velan 6-in. 1500 psig 
     ASA swing check valves (Velan Drawing No. 78704). 

     The valves were disassembled and the disks were found to be stuck in 
     the full-open position due to interference between the disk nut 
     lockwire (disk wire) and the valve body. The disk nut and its shaft can 
     rotate freely, and, in certain random rotational positions, this 
     interference is likely to occur. 

     The licensee has replaced the disk wire with a cotter pin that will not
     cause interference with the valve body for any rotational position. 
     Subsequent inspection of the other check valves in the low head safety 
     injection lines 
.

                                                         IN 81-30          
                                                         September 28, 1981 
                                                         Page 2 of 2       

     was performed. These valves were found to be closed. The lock wires 
     were nevertheless replaced with cotter pins. 

     The drawing for the same valve used at the Prairie Island plant was 
     also checked. The drawing (Velan Drawing No. 78704) is annotated to 
     require that the lock wire be tack welded down (so it cannot interfere 
     with the valve body). Because this detail is not uniform on the subject 
     drawing and can vary from plant to plant, a verification and/or 
     changeout on this locking device may be necessary. 

Additional occurrences with Velan swing check valves are described in IE 
Bulletin 79-04, "Incorrect Weights for Swing Check Valves Manufactured by 
Velan Engineering Corporation," and in Information Notice No. 80-41, "Failure
of Swing Check Valve in the Decay Heat Removal System at Davis-Besse Unit 
No. 1." 

This information is provided as notification of a potentially significant 
matter. It is expected that recipients will review the information for 
possible applicability to their facilities. No specific action or response 
is requested at this time. If you have questions regarding this matter, 
please contact the Director of the appropriate NRC Regional Office. 

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