Which of the following best describes cryogenic container stressors?

• A. Thermal, Chemical, and Mechanical
• B. Thermal and Electrical
• C. Chemical and Electrical
• D. Mechanical and Electrical

Answer: (A)

Cryogenic container stressors come from three main areas: thermal, chemical, and mechanical. The extreme low temperatures cause thermal stresses as materials contract, and because different materials shrink at different rates, joints, seals, and insulation can experience strain or even cracking if not properly matched. Thermal shock can occur if a portion of the container changes temperature much faster than the rest, creating sudden stress within the structure. Chemical stressors involve how the container materials interact with the cryogenic fluid—some materials can become brittle, corrode, or otherwise degrade under cryogenic conditions, and reactive fluids (such as oxygen-rich liquids) can pose additional compatibility hazards. Mechanical stressors stem from the internal pressure of the stored liquid and any boil-off gas, plus external forces from handling, vibration, and structural loads on the shell and closures. Electrical factors are not typically treated as a primary container stressor in this context.