FASTGRASS. Fission Product Release Ubase Fuels
- Argonne National Lab., IL (United States)
FASTGRASS is a mechanistic code that predicts atomic and bubble behavior of fission gas in UO2 fuel under steady-state and transient conditions. FASTGRASS also calculates the behavior of the volatile fission products (VFP) I, Cs, and Te as well as the alkaline earth fission products (AEFP) Ba and Sr. The chemistry models include the reaction products Cs2MoO4, Cs2UO4, BaO, SrO and BaUO4. Both the condensed and vapor phases of BaO and SrO are considered. A basic premise of the FASTGRASS analysis is that the noble gases provide the major pathways for fission product release as well as the major reaction sites required for vapor phase formation of various reaction products. Models are included for fission-product generation, atomic migration, bubble nucleation and re-solution, bubble migration and coalescence, channel formation on grain faces, the interlinking of porosity along grain edges, and microcracking on both the amount of fission products released and on their distribution within the fuel. Mechanistic models are also included for grain growth/grain boundary sweeping, and for the behavior of fission products under liquefaction/dissolution and fuel melting conditions. FASTGRASS uses a realistic equation of state for xenon, experimentally derived steady-state bubble mobilities, and phenomenological modeling of bubble mobilities during transient nonequilibrium conditions to calculate the swelling due to retained fission- gas bubbles in the lattice, on grain faces, and along the grain edges. FASTGRASS also calculates fission-product release as a function of time for steady-state and transient thermal conditions. Two variants of the software are included: FASTGRASS, for multinode calculations, and PARAGRASS, for single-node calculations. PARAGRASS can be used as a module in a larger program.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research
- OSTI ID:
- 139290
- Report Number(s):
- ESTSC/NRC-000086C017000; NESC-1095
- Resource Relation:
- Other Information: PBD: 1 Sep 1992
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COMPUTERS
INFORMATION SCIENCE
MANAGEMENT
LAW
MISCELLANEOUS
22 NUCLEAR REACTOR TECHNOLOGY
05 NUCLEAR FUELS
F CODES
FISSION PRODUCT RELEASE
URANIUM OXIDES
COMPUTER PROGRAM DOCUMENTATION
EQUATIONS OF STATE
GASES
HEAT TRANSFER
BUBBLES
NUCLEAR FUELS
VOLATILE MATTER
FISSION PRODUCTS
ALKALINE EARTH ISOTOPES
REACTOR LATTICES
GRAIN GROWTH
GRAIN BOUNDARIES