NRC SFST ISG-18: The Design and Testing of Lid Welds on Austenitic Stainless Steel Canisters as the Confinement Boundary for Spent Fuel Storage

The purpose of this ISG is to address the design and testing of the various closure welds (“lid
welds”) associated with the redundant closure of all-welded austenitic stainless steel canisters:

As an acceptable confinement boundary under 10 CFR Part 72.236(e) (Ref. 1) for
purposes of demonstrating no credible leakage of radioactive material during storage
and satisfying the dose limits under normal and off-normal conditions in 10 CFR Parts
72.104(a) and 72.106(b).

This staff guidance is not a regulatory requirement. Instead, it is one acceptable method for
meeting the applicable regulatory requirements. It is provided to reduce applicant burden and
staff review effort. Use of this guidance by applicants is optional. Other means for satisfying
the appropriate regulatory requirements may be proposed for staff review. However, deviation
from this guidance in whole or in part may result in more lengthy staff review schedules. This
guidance does not apply to Part 71 transport designs, and has not been considered for such
applications. This ISG does not address the testing of the welds comprising a storage cask
body.

Revision 1.