The purpose of this interim staff guidance (ISG) is to supplement standard review plan guidance
for evaluating the helium leakage testing and ASME Code1
required pressure
(hydrostatic/pneumatic) testing that is specified for the dry storage system (DSS) confinement
boundary. These acceptance tests are necessary to clearly demonstrate that the DSS
confinement boundary has been fabricated in accordance with the design criteria, and that its
operation complies with the intended safety bases of the confinement system and regulatory