This study evaluates the structural integrity and design optimization of the i-SMR CRDM housing under operating conditions (15.5 MPa, 325°C). Using a thermal-structural coupled FE analysis, a parametric study was conducted by varying the housing thickness from 10 mm to 3 mm. Results showed that while radial deformation remained stable (~0.33 mm) due to thermal expansion, axial displacement increased by 17.1% as thickness decreased. Stress linearization, based on ASME Section III NB-3200, identified 4 mm as the critical minimum thickness, yielding a combined stress ( ) of 275.24 MPa, which satisfies the shakedown limit () of 282 MPa. In contrast, the 3 mm model exceeded the limit at 357.62 MPa. The baseline 10 mm design exhibited a high safety factor of 3.21, confirming its conservative reliability. These findings provide a quantitative basis for the lightweight design of SMR pressure boundaries while ensuring strict nuclear safety standards.

Abstract
1. 서 론
2. 이론적 배경 및 평가 기준
    2.1 Stress Classification and Linearization
    2.2 Design Limits
    2.3 ASME 규격에 따른 두께 계산
3. Parametric study
    3.1 Mesh
    3.2 Analysis Setting
    3.3 Result of Thermal-Structural CoupledAnalysis
4. Conclusions
References

• 곽효서(Assistant professor, Mechanical Engineering Major) | Hyo-seo Kwak Corresponding author