Presentation made at the Electric Power Research Institute (EPRI) Extended Storage Collaboration Project (ESCP) meeting November 2016 discussing the status of nondestructive examinations being performed on high burnup (HBU) sent nuclear fuel (SNF) rods at Oak Ridge National Laboratory and proposed destructive examinations that will be performed over the next several years.

The recent experiments conducted by Argonne National Laboratory on high burnup fuel cladding material property show that the ductile to brittle transition temperature of high burnup fuel cladding is dependent on: (1) cladding material, (2) irradiation conditions, and (3) drying-storage histories (stress at maximum temperature) [1]. The experiment results also show that the ductile to brittle temperature increases as the fuel burnup increases.

The U.S. industry’s limited efforts at licensing transportation packages characterized as “highcapacity,”
or containing “high-burnup” (>45 GWd/MTU) commercial spent nuclear fuel
(CSNF), or both, have not been successful considering existing spent-fuel inventories that will
have to be eventually transported. A holistic framework is proposed for resolving several CSNF
transportation issues. The framework considers transportation risks, spent-fuel and cask-design

Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

This report investigates trends in the radiological decay properties and changes in relative nuclide importance associated with increasing enrichments and burnup for spent LWR fuel as they affect the areas of criticality safety, thermal analysis (decay heat), and shielding analysis of spent fuel transport and storage casks. To facilitate identifying the changes in the spent fuel compositions that most directly impact these application areas, the dominant nuclides in each area have been identified and ranked by importance.

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.

Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

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 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

This calculation compares results from criticality evaluations for a 21-assembly pressurized water reactor (PWR) waste package based on 12 axial burnup profile representations for commercial spent nuclear fuel (SNF) assemblies. The burnup profiles encompass the axial variations caused by different fuel assembly irradiation histories in a commercial PWR, including end effects, and the concomitant effect on reactivity in the waste package. The bounding axial burnup profiles in Table T of reference 6.3 are used for this analysis.

In 1999, the United States Nuclear Regulatory Commission (U.S. NRC) initiated a research program
to support the development of technical bases and guidance that would facilitate the implementation of burnup
credit into licensing activities for transport and dry cask storage. This paper reviews the following major areas of
investigation: (1) specification of axial burnup profiles, (2) assumption on cooling time, (3) allowance for
assemblies with fixed and removable neutron absorbers, (4) the need for a burnup margin for fuel with initial