Benchmark Calculations for the Diluted Highly Enriched Uranium (HEU) and Aluminum Experiment

Conference · Sat Nov 10 23:00:00 EST 2001

OSTI ID:975518

Loaiza, David J. ^[1]; Sanchez, Rene G. ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

The HEU-Al experiment was performed using the Planet universal critical assembly at Los Alamos Critical Experiment Facility (LACEF) in Los Alamos National Laboratory. This experiment consisted of placing HEU foils interspersed with aluminum plates in a column stack. These uranium foils were moderated and reflected by polyethylene square plates. This experiment was performed to measure the prompt neutron decay constants in uranium systems diluted by matrix materials. This experimental set-up yielded a Al/²³⁵U ratio of 60:1. The experimental k_eff was 1.001 and the modeled MCNP k_eff was 1.0016±0.0004. This report summarizes the benchmark calculations performed to validate the experiment. The experimental arrangement is depicted in Figure 1. As Figure 1 illustrates the stack is divided into two parts. The bottom half of the stack rest on an aluminum support plate which is 1 inch thick. The top half of the experiment rest on 0.75 inch thick polyethylene plate. Criticality is achieved by decreasing the gap between the top and bottom portions of the stack. To disassemble the configuration the bottom stack is dropped to its initial position. There are no other control or safety rods inside the assembly.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 975518
• Report Number(s): LA-UR--01-3146
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALUMINIUM
BENCHMARKS
CONFIGURATION
CRITICALITY
DECAY
HIGHLY ENRICHED URANIUM
K-Effective
LANL
LOS ALAMOS
Los Alamos Critical Experiment Facility (LACEF)
MATRIX MATERIALS
MCNP
Nuclear Criticality Safety Program (NCSP)
PLANETS
PLATES
POLYETHYLENES
PROMPT NEUTRONS
Planet Universal Critical Assembly
URANIUM