Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Annular seed-blanket reactor critical experiments (LWBR Development Program)

Technical Report ·
OSTI ID:7010774

A series of one-, two-, and three-module cores containing highly enriched UO/sub 2/ seeds and ThO/sub 2/ blankets have been studied. The purpose of this program was to compare design calculations with various measured core parameters. These parameters included the critical eigenvalues, seed power distributions, fast and thermal activation traverses, epithermal to thermal Th capture ratios, epithermal to thermal /sup 235/U fission ratios, thermal disadvantage factors, and fast advantage factors. In addition, some information on core intermodule coupling was obtained. Each module of the assemblies consisted of a narrow hexagonal annular /sup 235/U seed and an inner and outer ThO/sub 2/ blanket. The cores were designed to be nearly clean critical with no significant internal structure except fuel rod cladding in the active portion of the core. This allowed a fair test of the design model on highly absorbing narrow seed regions in a ThO/sub 2/ blanket. The design model was found to agree quite well with experimental results. The critical eigenvalues for all cores were consistent and close to unity. Near the seed-blanket interface, discrepancies between calculated and experimental traverses were noted and have been explained by spectrum-weighted cross sections and a higher order approximation to transport calculations. Monte Carlo calculations gave good agreement with experiment for thermal disadvantage factors and fast advantage factors. Fast leakage effects were found to be important in the calculation of the fast advantage factor in the seed region. (NSA 21: 21653)

Research Organization:
Bettis Atomic Power Lab., Pittsburgh, PA (USA)
DOE Contract Number:
AT(11-1)-GEN-14
OSTI ID:
7010774
Report Number(s):
WAPD-TM-621
Country of Publication:
United States
Language:
English