Presentation made at International Conference on The Management of Spent Nuclear Fuel from Nuclear Power Reactors, An Integrated approach to the Back-End of the Fuel Cycle (IAEA-CN-226). The purpose of the conference was to highlight the importance of an integrated long-term approach to the management of spent fuel from nuclear power reactors.

This paper presents an assessment of the benefits for extended burnup credit in transporting
pressurized-water-reactor (PWR) spent nuclear fuel (SNF) in the United States. A prototypic 32-
assembly cask and the current regulatory guidance were used as bases for this assessment. By
comparing recently released PWR discharge data with actinide-only-based loading curves, this
evaluation shows that additional negative reactivity (through either increased credit for fuel burnup or

Following the proposals for nuclear fuel assurance of International Atomic Energy
Agency (IAEA) Director General Mohamed ElBaradei, former Russian President Vladimir V.
Putin, and U.S. President George W. Bush, joint committees of the Russian Academy of
Sciences (RAS) and the U.S. National Academies (NAS) were formed to address these and other
fuel assurance concepts and their links to nonproliferation goals. The joint committees also
addressed many technology issues relating to the fuel assurance concepts. This report provides

In July 1999, the U.S. Nuclear Regulatory Commission (NRC) Spent Fuel Project Office
(SFPO) issued Interim Staff Guidance 8 Revision 1 (ISG8R1) to provide recommendations for the use
of burnup credit in storage and transport of pressurized-water reactor (PWR) spent fuel. Subsequent to
the issuance of ISG8R1, the NRC Office of Regulatory Research (RES) has directed an effort to
investigate the technical basis for extending the criteria and recommendations of ISG8R1 to allow

The purpose of this activity is to develop a representative “limiting” axial burnup profile for pressurized water reactors (PWRs), which would encompass the isotopic axial variations caused by different assembly irradiation histories, and produce conservative isotopics with respect to criticality. The effect that the low burnup regions near the ends of spent fuel have on system reactivity is termed the “end-effect”. This calculation will quantify the end-effects associated with Pressurized Water Reactor (PWR) fuel assemblies emplaced in a hypothetical 21 PWR waste package.

The purpose of this calculation is to develop axial profiles for estimating the axial variation in burnup of a boiling water reactor (BWR) assembly spent nuclear fuel (SNF) given the average burnup of an assembly. A discharged fuel assembly typically exhibits higher burnup in the center and lower burnup at the ends of the assembly. Criticality safety analyses taking credit for SNF burnup must account for axially varying burnup relative to calculations based on uniformly distributed assembly average burnup due to the under-burned tips.

The benefits of burnup credit and the technical issues associated with utilizing burnup credit in spent
nuclear fuel (SNF) casks have been studied in the United States for almost two decades. The issuance of the
U.S. Nuclear Regulatory Commission (NRC) staff guidance for actinide-only burnup credit in 2002 was a
significant step toward providing a regulatory framework for using burnup credit in transport casks. However,
adherence to the current regulatory guidance (e.g., limit credit to actinides) enables only about 30% of the existing

Presentation made at International Conference on The Management of Spent Nuclear Fuel from Nuclear Power Reactors, An Integrated approach to the Back-End of the Fuel Cycle (IAEA-CN-226). The purpose of the conference was to highlight the importance of an integrated long-term approach to the management of spent fuel from nuclear power reactors.

Presentation made at International Conference on The Management of Spent Nuclear Fuel from Nuclear Power Reactors, An Integrated approach to the Back-End of the Fuel Cycle (IAEA-CN-226). The purpose of the conference was to highlight the importance of an integrated long-term approach to the management of spent fuel from nuclear power reactors.

Presentation made at International Conference on The Management of Spent Nuclear Fuel from Nuclear Power Reactors, An Integrated approach to the Back-End of the Fuel Cycle (IAEA-CN-226). The purpose of the conference was to highlight the importance of an integrated long-term approach to the management of spent fuel from nuclear power reactors.