Session: OAC-06-02 Continued Safe Operation of Existing Assets-2

Paper Number: 125425

125425 - Parametric Evaluation of Fillet Welded Patches With Reinforcing Plug Welds for Pressure Vessels Using Finite Element Analysis 

The inspection of the Moderator Purification System Heat Exchanger identified microbiological corrosion at several locations on the shell side. The minimum measured thicknesses at different locations are projected to be lower than the pressure based minimum wall thickness when projected to the targeted end of life of the vessel. To ensure a continuous and safe operation of the heat exchanger until replacement, this work presents a repair strategy of the corroded areas on the shell using fillet welded patches with reinforcing plug welds following the procedure in Article 207 of ASME PCC-2-2022 edition. Plug welds can be engineered to bear a share of up to 30% of the patch plate's load and must be appropriately positioned to carry their allotted portion of the load. The plug welds serve to decrease the bending moments experienced by the fillet welds, enabling the repair of large defects. ASME PCC-2 provides a wide range for the plug welds geometrical parameters (such as distance from the edge and diameter). In this work, a parametric 3D finite element study is performed to determine the optimized configuration of plug welds that reduces the stresses in the fillet welds. The results show significant reductions in the fillet weld stresses, up to 50%, when the diameter and distance from the patch edge to the plugs are varied within the limits provided by the ASME PCC-2 guidelines.

Presenting Author: Ahmed Alian Next Structural Integrity Inc

Presenting Author Biography: Dr. Alian is a professional mechanical Engineer with extensive experience in management, analysis, design, and construction/field support of pressure boundary components in nuclear power plants. He has a strong background in solid mechanics, structural analysis, fracture mechanics, and finite element analysis with 15 years of research and industrial experience. Dr. Alian Published over 30 papers in Engineering Journals, coinvented a high-pressure cardiac action hydraulic pump, and taught different practical engineering subjects at top universities.

Authors:

Ahmed Alian Next Structural Integrity Inc
Ahmed Moussa Next Structural Integrity Inc
Luat Nguyen Next Structural Integrity Inc
Sadath Malik Next Structural Integrity Inc