# 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):

# Report Date:

## 1966-08-01

# Pagination or Media Count:

## 42.0

# 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:

# Subject Categories:

- Nuclear Fission Reactors (Non-Power)
- Fission Reactor Materials