The "Summary Report of Commercial Reactor Criticality Data for Davis-Besse Unit 1" contains the detailed information necessary to perform commercial reactor criticality (CRC) analyses for the Davis-Besse Unit 1 reactor.

The "Summary Report of SNF Isotopic Comparisons for the Disposal Criticality Analysis Methodology" contains a summary of the analyses that compare SNF measured isotopic concentrations (radiochemical assays) to calculated SNF isotop~c concentrations (SAS2H module ·orScale4.3). The results of these analyses are used to support the validation of the isotopic models for spent commercial light water reactor (LWR) fuel.

The "Summary Report of Commercial Reactor Criticality Data for Catawba Unit 1" contains the detailed information necessary to perform commercial reactor criticality (CRC) analyses for the Catawba Unit 1 reactor.

The "Summary Report of Commercial Reactor Criticality Data for LaSalle Unit 1" contains the detailed information necessary to perform commercial reactor criticality (CRC) analyses for the LaSalle Unit 1 (LS 1) reactor.

Spent Fuel Project Office Interim Staff Guidance - 8

Since a 1985 decision by President Reagan that a separate permanent repository for disposal of
defense high level waste was not required1, DOE has planned for disposal of all high-level waste
and spent fuel from national defense activities and DOE’s own research activities in a repository
for commercial waste developed under the Nuclear Waste Policy Act (NWPA). The Commission
has heard recommendations from some commenters2 that this decision be revisited, or even

This report evaluates the potential for directly disposing of licensed commercial Dual Purpose
Canisters (DPCs) inside waste package overpacks without reopening. The evaluation considers
the principal features of the DPC designs that have been licensed by the Nuclear Regulatory
Commission (NRC) as these relate to the current designs of waste packages and as they relate to
disposability in the repository. Where DPC features appear to compromise future disposability,
those changes that would improve prospective disposability are identified.

Spent Fuel Project Office, Interim Staff Guidance - 8, Revision 1

Since the mid-1980s, a significant number of studies have been directed at understanding the phenomena and
parameters important to implementation of burnup credit in out-of-reactor applications involving pressurizedwater-
reactor (PWR) spent fuel. The efforts directed at burnup credit involving boiling-water-reactor (BWR)
spent fuel have been more limited. This paper reviews the knowledge and experience gained from work
performed in the United States and other countries in the study of burnup credit. Relevant physics and analysis

Approximately 54,000 tons of spent nuclear fuel are stored at operating nuclear power plants and several decommissioned power plants throughout the country. Spent fuel storage at these sites was never intended to be permanent. The current Federal plan is to place the fuel in a repository for permanent disposal in Nevada at Yucca Mountain.

This research examines the practice of equating the reactivity of spent fuel to that of fresh fuel for the purpose of performing burnup credit criticality safety analyses for PWR spent fuel pool (SFP) storage conditions. The investigation consists of comparing kf estimates based on reactivity "equivalent" fresh fuel enrichment (REFFE) to kl estimates using the actual spent fuel isotopics.

The requirements of ANSI/ANS 8.1 specify that calculational methods for away-from-reactor
(AFR) criticality safety analyses be validated against experimental measurements. If credit for the
negative reactivity of the depleted (or spent) fuel isotopics is desired, it is necessary to benchmark
computational methods against spent fuel critical configurations. This report summarizes a portion
of the ongoing effort to benchmark AFR criticality analysis methods using selected critical
configurations from commercial pressurized-water reactors (PWR).

All activities which involve the use of radioactive material inevitably result in nuclear waste as a by-product of their operation. Most of the waste produced by such activities as medical diagnosis and therapy, field and laboratory research, and industrial processes is low-level radioactive waste—primarily small amounts of radioactivity in a large volume of matter.

Utilization of burnup credit in criticality safety analysis for long-term disposal of spent
nuclear fuel allows improved design efficiency and reduced cost due to the large mass of fissile
material that will be present in the repository. Burnup-credit calculations are based on depletion
calculations that provide a conservative estimate of spent fuel contents (in terms of criticality
potential), followed by criticality calculations to assess the value of the effective neutron

The isotopic composition of mixed-oxide fuel (fabricated with both uranium and plutonium
isotopes) discharged from reactors is of interest to the Fissile Material Disposition Program. The
validation of depletion codes used to predict isotopic compositions of MOX fuel, similar to studies
concerning uranium-only fueled reactors, thus, is very important. The EEI-Westinghouse Plutonium
Recycle Demonstration Program was conducted to examine the use of MOX fuel in the San Onofre

The "Summary Report of Commercial Reactor Criticality Data for Sequoyah Unit 2" contains the detailed information necessary to perform commercial reactor criticality (CRC) analyses for the Sequoyah Unit 2 reactor.

At the request of the U.S. Congress, the National Academies assessed the safety and
security of spent nuclear fuel stored in pools and dry casks at commercial nuclear power
plants in the United States. The public report can be viewed on the National Academies
Press website at http://books.nap.edu/catalog/11263.html.

Spent Fuel Project Office, Interim Staff Guidance - 8, Revision 2 - Burnup Credit in the Criticality Safety Analyses of PWR Spent Fuel in Transport
and Storage Casks

The requirements of ANSI/ANS 8.1 specify that calculational methods for away-from-reactor
criticality safety analyses be validated against experimental measurements. If credit for the negative
reactivity of the depleted (or spent) fuel isotopics is desired, it is necessary to benchmark
computational methods against spent fuel critical configurations. This report summarizes a portion
of the ongoing effort to benchmark away-from-reactor criticality analysis methods using critical
configurations from commercial pressurized-water reactors.

The Interim Staff Guidance on burnup credit for pressurized water reactor (PWR) spent nuclear fuel (SNF), issued by the United States Nuclear Regulatory Commission's (U.S. NRC) Spent Fuel Project Office, recommends the use of analyses that provide an "adequate representation of the physics" and notes particular concern with the "need to consider the more reactive actinide compositions of fuels burned with fixed absorbers or with control rods fully or partly inserted." In the absence of readily available information on the extent of control rod (CR) usage in U.S.

The "Summary Report of Commercial Reactor Critical Analyses Perfonned for the Disposal Criticality Analysis Methodology" contains a summary of the commercial reactor critical (CRC) analyses used to support the validation of the criticality models for spent commercial light water reactor (LWR) fuel.

Isotopic characterization of spent fuel via depletion and decay calculations is necessary for
determination of source terms for subsequent system analyses involving heat transfer, radiation
shielding, isotopic migration, etc. Unlike fresh fuel assumptions typically employed in the criticality
safety analysis of spent fuel configurations, burnup credit applications also rely on depletion and
decay calculations to predict the isotopic composition of spent fuel. These isotopics are used in