MAFIA: A one-dimensional burn-up code. Project DRAGON

Technical Report · Mon Jul 15 04:00:00 EDT 1963

OSTI ID:4108373

Massimo, L.; Schloesser, J.

Spectral changes due to the depletion of fissionable materials and build-up of fission products have a strong influence on the effective cross sections of all the various isotopes and on the reactivity of a long irradiated core. Since, as far as the authors know, no one-dimensional burn-up code suitable for high temperature graphite reactors provides the possibility of treating spectrum changes with time, a programme, MAFIA, has been written which combines the General Atomic burn-up code FEVER with the Dragon Project multi-group diffusion code MUPO. FEVER is an up to four-group, one-dimensional burn-up programme which uses a few group cross section library. In order to follow spectral changes of the neutron flux it is necessary to modify the library for the different parts of the reactor core at each time step of the burn-up calculation. As this has to be repeated many times during the lifetime of a core, great care has been taken to speed up the spectrum evaluation. MUPO is a programme which meets these requirements. It is a zero-dimensional 43-group diffusion theory code, and its source iteration routine is used for the spectra calculation. It permits the introduction of energy-dependent leakage. 43-group cross sections and scattering kernels are obtained from a library tape. This tape is used only once so that all spectrum calculations can be performed without any time consuming tape manipulation. To allow for spectrum changes across the core, this can be divided into a maximum of 4 regions and the MUPO spectrum calculation will be repeated for each zone at each time step. To improve the accuracy of the spectrum calculation an energy dependent leakage, obtained by the FEVER one-dimensional diffusion calculation of the previous time step, is used in MUPO, By this procedure of coupling spectrum and burn-up calculations it is not necessary to provide a few group cross section library for the beginning of life which saves considerable time in input preparation and card manipulation. Few group cross sections for the reflector, however, have to be specified as they do not change markedly with burn-up.

• Research Organization: Atomic Energy Establishment (AEE), Winfrith, England (United Kingdom)
• Sponsoring Organization: Atomic Energy Establishment (AEE)
• NSA Number: NSA-24-041027
• OSTI ID: 4108373
• Report Number(s): DP-Report--203
• Country of Publication: United Kingdom
• Language: English

Related Subjects

BURNUP
COMPUTER PROGRAMS/MAFIA
for fuel burnup in high temperature graphite moderated reactors
FORTRAN for IBM 7090
COMPUTERS
DIGITAL SYSTEMS
DRAGON
FORTRAN
FUELS
HIGH-TEMPERATURE GAS-COOLED REACTOR EXPERIMENT/fuel burnup in
MAFIA code for
IBM 7090
MAFIA-CODE
N38170* --Power Reactor Development--Operation & Economics
PROGRAMMING
REACTORS