CRITICAL EXPERIMENTS AND ANALYSIS OF HOMOGENEOUS HEAVY WATER SYSTEM. 20 PERCENT ENRICHED U-D$sub 2$O REFLECTOR

Technical Report · Sun Apr 01 04:00:00 EST 1962

OSTI ID:4766731

An aqueous homogeneous critical facility was constructed. A series of critical experiments was performed on the system in which heavy water reflector surrounded heavy water solutions of uranyl sulfate with a U/sup 235/ enrichment of 20%. Heavy water molecule to U/sup 235/ atom ratio in the solutions ranged from 3600 to 800 depending on the core diameter. Space dependencies of thermal neutron spectra in these systems were studied by the integral method with Lu. Deviations of epithermal neutron spectra from l/E distribution were also investigated by the cadmium ratio method with In, Au, Pd, and Co. In theoretical analysis of these systems, leakage of fast neutrons from the core and competition of the leakage with resonance absorption in the core are important factors. Therefore the resonance escape probability was defined rigorously and a multigroup model was applied. The group constants were determined by averaging over spectra which were calculated by the Greuling Goertzel approximation. Agreements between theoretical and experimental results are satisfactory except perturbation terms. Discrepancies in the effective multiplication factors do not exceed 1%. Spatial distributions of the thermal, in-resonance, and fast neutron fluxes are well reproduced by the present theory. An agreement of the theoretical cadmium ratios in the core with the experimental values indicates that the leakage of fast neutrons from the core is treated adequately. (auth)

• Research Organization: Japan Atomic Energy Research Inst., Tokyo
• NSA Number: NSA-16-030999
• OSTI ID: 4766731
• Report Number(s): JAERI-1034
• Country of Publication: Japan
• Language: Japanese

Related Subjects

COBALT
CRITICAL ASSEMBLIES
CRITICALITY
DISTRIBUTION
ENRICHMENT
FAST NEUTRONS
GOLD
GROUP THEORY
HEAVY WATER
HOMOGENEOUS REACTORS
INDIUM
LEAD
OXIDES
PHYSICS
REFLECTORS
RESONANCE ESCAPE PROBABILITY
SOLUTIONS
SULFATES
THERMAL NEUTRONS
URANIUM 235
URANYL COMPOUNDS