The design of a wooden impact limiter equipped to a transportation cask for radioactive materials was optimized. According to International Atomic Energy Agency Safety Standards, 9 m drop tests should be performed on the transportation cask to evaluate its structural integrity in a hypothetical accident condition. For impact resistance, the size of the impact limiter should be properly determined for the impact limiter to absorb the impact energy and reduce the impact force. Therefore, the design parameters of the impact limiter were optimized to obtain a feasible optimal design. The design feasibility criteria were investigated, and several objectives were defined to obtain various design solutions. Furthermore, a probabilistic approach was introduced considering the uncertainties included in an engineering system. The uncertainty of material properties was assumed to be a random variable, and the probabilistic feasibility, based on the stochastic approach, was evaluated using reliability. Monte Carlo simulation was used to calculate the reliability to ensure a proper safety margin under the influence of uncertainties. The proposed methodology can provide a useful approach for the preliminary design of the impact limiter prior to the detailed design stage.

1. Introduction
2. Impact and Absorbable Energy ofImpact Limiter
    2.1 Impact and Absorbable Energy
    2.2 Maximum Crushed Volume
3. Design Optimization of Impact Limiter
    3.1 Design Constraint
    3.2 Formulation of Design Optimization ofImpact Limiter
    3.3 Design Feasibility of Initial Design
    3.4 Design Optimization of Impact Limiter
4. Probabilistic Design of Impact Limiter
    4.1 Definition of Uncertainties Included inDesign of Impact Limiter
    4.2 Calculation of Failure Probability UsingMCS
    4.3 Sensitivity Analysis of Failure Probability
    4.4 Probabilistic Design of Impact Limiter
5. Conclusions
Acknowledgements
REFERENCES

• Jongmin Lim(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea) Corresponding author
• Woo-Seok Choi(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea)