Information Notice No. 83-71: Defects in Load-bearing Welds on Lifting Devices for Vessel Head and Internals
SSINS No.: 6835
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
October 27, 1983
Information Notice No. 83-71: DEFECTS IN LOAD-BEARING WELDS ON LIFTING
DEVICES FOR VESSEL HEAD AND INTERNALS
All holders of nuclear power reactor operating licenses (OL) or construction
This information notice provides notification of the potential for failure
of reactor vessel head and internals lifting devices manufactured by Babcock
and Wilcox Company. It is expected that addressees will review the
information provided here for applicability to their facilities. No specific
response or action is required.
Description of Circumstances:
A lifting device for the vessel head and internals supplied to Florida Power
Corporation by Babcock and Wilcox was found to have weld defects in
load-bearing welds. If the welding defects were to go uncorrected, they
could jeopardize the capability of the lifting system to safely handle
safety-related components within reactor compartments.
The subject lifting device was fabricated to industry standards. However, a
subsequent regulatory requirement, NUREG-0612 requires that the lifting
device be tested in accordance with ANSI N14.6 on the basis that it is to
carry heavy loads over safety-related systems.
Florida Power Corporation committed to perform appropriate non-destructive
examination (NDE) on the device as required. Results of the NDE (magnetic
particle) revealed four indications in welds on the tripod, one on the
turnbuckle, and one on the latchblock. In addition, a visual examination
revealed that several welds showed undercut, porosity, and cold lapping.
Defects found were considered potential safety hazards if not repaired and
suggest that the industry standards used were inadequate to meet the service
intended. As a remedy, the welds on the tripod and the latchblock were
repaired and the turnbuckles were replaced with a solid unwelded model.
Subsequent to repairs, the lifting device was qualified for use as
designated by performance of NDE and load testing in accordance with ANSI
N14.6 as required by NUREG-0612. Although
October 27, 1983
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load testing in accordance with ANSI N14.6 satisfies the letter of NRC
requirements, prudence would indicate the desirability, of rigorous NDE, to
improve confidence that lifting and handling systems, when tested, will not
The example cited was furnished by Babcock and Wilcox, but the NRC concern
applies to both standard and custom elements of heavy-load-handling systems.
If you have any questions regarding this matter, please contact the Regional
Administrator of the appropriate NRC Regional Office, or this office.
Edward L. Jordan Director
Division of Emergency Preparedness
and Engineering Response
Office of Inspection and Enforcement
Technical Contact: J. B. Henderson, IE
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