Isotopic Validation for PWR Actinide-Only Burnup Credit Using Yankee Rowe Data

Conference · Mon May 11 04:00:00 EDT 1998

OSTI ID:645516

Safety analyses of criticality control systems for transportation packages include an assumption that the spent nuclear fuel (SNF) loaded into the package is fresh or unirradiated. In other words, the spent fuel is assumed to have its original, as-manufactured U-235 isotopic content. The "fresh fuel" assumption is very conservative since the potential reactivity of the nuclear fuel is substantially reduced after being irradiated in the reactor core. The concept of taking credit for this reduction in nuclear fuel reactivity due to burnup of the fuel, instead of using the fresh fuel assumption in the criticality safety analysis, is referred to as "Burnup Credit." Burnup credit uses the actual physical composition of the fuel and accounts for the net reduction of fissile material and the buildup of neutron absorbers in the fuel as it is irradiated. Neutron absorbers include actinides and other isotopes generated as a result of the fission process. Using only the change in actinide isotopes in the burnup credit criticality analysis is referred to as "Actinide-Only Burnup Credit." The use of burnup credit in the design of criticality control systems enables more spent fuel to be placed in a package. Increased package capacity results in a reduced number of storage, shipping and disposal containers for a given number of SNF assemblies. Fewer shipments result in a lower risk of accidents associated with the handling and transportation of spent fuel, thus reducing both radiological and nonradiological risk to the public. This paper describes the modeling and the results of comparison between measured and calculated isotopic inventories for a selected number of samples taken from a Yankee Rowe spent fuel assembly.

• Research Organization: TRW Environmental Safety Systems, Inc., Vienna, VA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC08-91RW00134
• OSTI ID: 645516
• Report Number(s): DOE/RW/00134--M97-020; CONF-980516--; ON: DE98001301; BR: DB0306000
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
27BURNUPLIB
96 KNOWLEDGE MANAGEMENT AND PRESERVATION
ACTINIDES
BURNUP
COMPARATIVE EVALUATIONS
CRITICALITY
Evaluated Nuclear Data File (ENDF)
Fuel Pins
Nuclear Criticality Safety Program (NCSP)
Pressurized Water Reactor (PWR)
ROWE YANKEE REACTOR
Reactor Core
SAFETY ANALYSIS
SAS2H
SCALE 4/2
SPENT FUEL CASKS
Spent Nuclear Fuel (SNF)