Review of Information for Spent Nuclear Fuel Burnup Confirmation

The Interim Staff Guidance on burnup credit (ISG-8, revision 2) for pressurized-water-reactor spent
nuclear fuel in storage and transport casks, issued in 2002 by the U.S. Nuclear Regulatory Commission’s
Spent Fuel Project Office, recommends an out-of-core burnup measurement to confirm the reactor record
and compliance with the assembly burnup value used for cask loading acceptance. This recommendation
is intended to prevent unauthorized loading (i.e., misloading) of assemblies due to inaccuracies in reactor
burnup records and/or improper assembly identification, thereby ensuring that the appropriate subcritical
margin is maintained. The purpose of this report is to detail information and issues relevant to
preshipment burnup measurements when using burnup credit in pressurized-water-reactor spent nuclear
fuel transport and storage casks. In particular, this report reviews the role of burnup measurements in the
regulatory guidance for demonstrating compliance with burnup loading criteria, burnup measurement
capabilities and experience, generation and accuracy of utility burnup records, fuel movement and
misloading experience, and the consequences of misloading assemblies in casks designed for burnup
credit.