Optimization of the Closure-Weld Region of cylindrical Containers for Long-Term Corrosion Resistance

Ceylan, Zekai ; Trabia, Mohamed B.

United States. Department of Energy. Yucca Mountain Project Office.

关键词: Crack Propagation;    Radioactive Waste Storage;    Welded Joints;    Mathematical Models;    42 Engineering;   

DOI  :  10.2172/786561
RP-ID  :  NONE
RP-ID  :  NONE
RP-ID  :  786561

美国|英语

来源: UNT Digital Library

【 摘 要 】

Welded cylindrical containers are susceptible to stress corrosion cracking (SCC) in the closure-weld area. An induction coil heating technique may be used to relieve the residual stresses in the closure-weld. This technique involves localized heating of the material by the surrounding coils. The material is then cooled to room temperature by quenching. A two-dimensional axisymmetric finite element model is developed to study the effects of induction coil heating and subsequent quenching. The finite element results are validated through an experimental test. The parameters of the design are tuned to maximize the compressive stress from the outer surface to a depth that is equal to the long-term general corrosion rate of Alloy 22 (Appendix A) multiplied by the desired container lifetime. The problem is subject to geometrical and stress constraints. Two different solution methods are implemented for this purpose. First, off-the-shelf optimization software is used to obtain an optimum solution. These results are not satisfactory because of the highly nonlinear nature of the problem. The paper proposes a novel alternative: the Successive Heuristic Quadratic Approximation (SHQA) technique. This algorithm combines successive quadratic approximation with an adaptive random search. Examples and discussion are included.