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Title: Benchmark calculations for the diluted highly enriched uranium (HEU) and aluminum experiment

Conference ·
OSTI ID:975518

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 60:1.1 The experimental keff was 1.001 and the modeled MCNP keff 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
OSTI ID:
975518
Report Number(s):
LA-UR-01-3146; TRN: US1006724
Resource Relation:
Conference: Submitted to: American Nuclear Society Conference, to be held in Reno, NV, November 11-15, 2001
Country of Publication:
United States
Language:
English