Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
GL80092
SSINS No.: 6820
Accession No.:
3008220246
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 value 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 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.
.
IEB 80-21
November 6, 1980
Page 2 of 3
Actions To Be Taken by Addressees:
For all power reactor licensees or holders of construction permits the
following actions are required:
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 you 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 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.
.
IEB 80-21
November 6, 1980
Page 3 of 3
Approved by GAO, B180225 (R0072); clearance expires November 30, 1980.
Approval was given under a blanket clearance specifically for identified
generic problems.
