Accession Number : AD0488450

Title :   ANALYSIS OF ASTR MELTDOWN CONFIGURATIONS.

Descriptive Note : Rept. for 1 Oct 64-1 Jan 66,

Corporate Author : GENERAL DYNAMICS FORT WORTH TX NUCLEAR AEROSPACE RESEARCH FACILITY

Personal Author(s) : McWhirter, J. W.

Report Date : AUG 1966

Pagination or Media Count : 42

Abstract : Potential fuel configuration from core meltdown of the Aerospace Systems Test Reactor (ASTR) have been analyzed to determine whether criticality is possible when water re-enters the core after melt solidification. The initial calculations, however, were made for the normal ASTR configuration with and without control rods as a check on the cross-section input data. A 1% decrease in the thermal-neutron absorption cross section of the core material provided the desired eigenvalue without control rods. An empirical scaling factor for the absorption cross section of each cell region containing a control rod was determined to be 0.105. The configuration resulting from an ASTR core meltdown in the horizontal mode of operation may be critical under certain restrictive conditions, such as a uniform porous melt containing all of the fuel; in this case, the multiplication constant is 1.066 for an H-to-U235 ratio of 500. If the meltdown occurs in the forward-end-up mode of operation, the multiplication constant is 1.066 for an H-to-U235 ratio of 500. Additional calculations resulted in a prompt-neutron lifetime of 0.000062 sec for the normal ASTR configuration and an effective delayed-neutron fraction of 0.0076 for the Ground Test Reactor (GTR). (Author)

Descriptors :   *REACTOR CORES), (*TEST REACTORS, MELTING, REACTOR SAFETY SYSTEMS, REACTOR KINETICS, REACTOR FUELS, WATER, REACTOR CONTROL, THERMAL NEUTRONS, FISSION PRODUCTS, NEUTRONS, URANIUM, REACTOR FUEL ELEMENTS, DENSITY, ALUMINUM, STAINLESS STEEL.

Subject Categories : Nuclear Fission Reactors(non-power)
      Fission Reactor Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE