Integrity of UF6 cylinders for outer pressure

Pressure resistance tests were carried out for a 30B-cylinder and 48Y-cylinder. They were tested for outer pressure which is equal to 15m depth for eight hours and 200m depth for one hour. It became clear that the maximum stress during the tests was below the yield stress of the structural material and there were no leakage after the test. As a result, the integrity of the cylinders was verified when the accidents were assumed that a vessel would sink during transport at sea. Buckling pressure tests were also carried out for each cylinder and it was ensured that the each cylinder has sufficient safety margin for outer pressure. Furthermore, when it is necessary to evaluate the critical buckling stress of the cylinder, it was proved that the calculating method of ASME code gave good agreement with the experimental results. (J.P.N.)