United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 80-21: Valve Yokes Supplied by Malcolm Foundry Company, Inc.

                                                            SSINS No.: 6820 
                                                            Accession No.: 
                                                            8008220246     
                                                            IEB 80-21 

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C. 20555
                                     
                              November 6, 1980

IE BULLETIN NO. 80-21: VALVE YOKES SUPPLIED BY MALCOLM FOUNDRY COMPANY, INC.

Description of Circumstances: 

On June 17, 1980, Pennsylvania Power and Light Company notified IE Region I 
that cracks had been discovered in the yokes of a number of valves in the 
residual heat removal (RHR) system at their Susquehanna Steam Electric 
Station. The potential for common-mode failure of the yokes on several 
valves in redundant, safety-related trains of the RHR system constitutes a 
failure mode whereby all RHR functions could be simultaneously lost. 
Specifically, the cracks were located in the radii at the yoke mounting 
flange-to-yoke vertical section interface. 

An analysis and evaluation of the most severely cracked valve yoke was 
performed by the valve manufacturer, Anchor Darling Valve Company. They 
concluded that the cracking was not due to casting defects, but rather was 
due to the yoke material not having the proper mechanical properties. 
Purchased as ASTM A-216, Grade WCB material, the actual valve yoke material 
had tensile and yield strengths below the minimum values listed in the ASTM 
material specification. The cracked valve yokes were all cast by Malcolm 
Foundry Company, Inc., of Newark, New Jersey. The foundry is no longer in 
business. 

Anchor Darling has begun a program of verifying the tensile strengths of the
other valve yokes cast by Malcolm and used on Anchor Darling valves at 
Susquehanna. To date, approximately half of the valve yokes have been 
tested. Of those tested, over 25 percent of the valve yokes have revealed 
Brinell hardness values significantly below the appropriate value obtained 
from the approximate relationship of Brinell hardness to tensile strength 
included in ASTM. Specification A-370. These additional valve yokes are on a 
wide range of valve sizes and are from a number of different purchase orders 
placed with Malcolm over a period of at least ten months during 1974 and 
1975. Thus, it appears that the problem is not isolated to one heat of 
material or to one short time period. Anchor Darling intends to replace the 
defective valve yokes at Susquehanna and to begin a testing program at other 
nuclear power plants under construction where valves with valve yokes cast 
by Malcolm have been provided. 

Since Malcolm Foundry Company, Inc., is no longer in business, the NRC staff
cannot determine directly if Malcolm has provided valve parts to other valve
manufacturers for use in nuclear power plants. 

Actions To Be Taken by Addressees: 

For all power reactor licensees or holders of construction permits the 
following actions are required: 
.

                                                           IEB 80-21 
                                                           November 6, 1980 
                                                           Page 2 of 2 

1.   Determine if any of the active valves in use or planned for use in 
     safety-related systems at your facility have valve parts cast by 
     Malcolm Foundry Company, Inc. If no valves are identified as having 
     potentially faulty material, indicate that this is the case and ignore 
     the remaining questions. 

2.   Licensees having active safety-related valves with potentially faulty 
     material shall immediately visually inspect for cracks all normally 
     accessible valve parts (i.e., those which can be inspected during 
     reactor operation). 

3.   Licensees or permit holders having active safety-related valves with 
     potentially faulty material shall identify the manufacturer(s) of these
     valves and either: 

     a.   Verify that all valve parts cast by Malcolm have mechanical 
          properties in accordance with the ASTM material specification; if 
          such is not the case, then comply with either b. or c. below also.

     b.   Replace the defective materials and/or valves. 

     c.   Identify any other corrective actions that may be exercised and 
          the basis for such actions. 

For plants with an operating license, the results of your initial 
determination (item 1), visual inspection results (item 2), a list of 
affected valve manufacturers, your planned action (item 3), and the schedule
for accomplishing this action shall be reported within thirty days of the 
date of this bulletin to the Director of the appropriate NRC Regional Office
with a copy sent to the NRC Office of Inspection and Enforcement, Division 
of Reactor Construction Inspection, Washington, DC 20555. 

For plants with a construction permit, the results of your initial 
determination (item 1), a list of affected valve manufacturer(s), your 
planned action (item 3) and the schedule for accomplishing this action shall
be reported within sixty days of the date of this bulletin to the Director 
of the appropriate NRC Regional Office with a copy sent to the NRC Office of
Inspection and Enforcement, Division of Reactor Construction Inspection, 
Washington, DC 20555. 

Compliance with this bulletin by the licensees does not relieve the affected
valve manufacturers from the reporting requirements of 10 CFR Part 21. 

If you desire additional information regarding this matter, please contact 
the appropriate IE Regional Office. 

Approved by GAO, B180225 (ROO72); clearance expires November 30, 1980. 
Approval was given under a blanket clearance specifically for identified 
generic problems. 
Page Last Reviewed/Updated Tuesday, July 23, 2013