Evaluation of Plutonium Hemisphere Critical Experiments Partially Reflected by Steel and Oil

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Nuclear Technology

OSTI ID:1031139

Bess, John D

A series of 15 critical experiments performed at the Rocky Flats Critical Mass Laboratory in the late 1960s were evaluated and then determined to represent acceptable benchmark experiments for the validation of calculational methods. This series of experiments was part of a larger set of experiments performed to evaluate operational safety margins at the Rocky Flats Plant. The experiments consisted of bare plutonium metal hemishells reflected by steel hemishells of increasing thickness and motor oil. The hemishell assembly was suspended within dual aluminum tanks. Criticality was achieved by pumping oil into the tanks such that effectively infinite reflection was achieved in all directions except directly above the assembly; then the critical oil height was recorded. The results of these experiments had been initially ignored because early computational methods had been inadequate to analyze partially-reflected configurations. The dominant uncertainties include the uncertainty in the average plutonium density and the composition of materials in the gaps between the plutonium hemishells. Simple and detailed benchmark models were developed. Eigenvalue calculations using MCNP5 and ENDF/B-VII.0 were within 2s of the benchmark values. This benchmark evaluation has been added to the ICSBEP Handbook.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: DOE - NE
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1031139
• Report Number(s): INL/JOU-10-20593
• Journal Information: Nuclear Technology, Journal Name: Nuclear Technology Journal Issue: 1 Vol. 177; ISSN 0029-5450; ISSN NUTYBB
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
97 MATHEMATICS AND COMPUTING
ALUMINIUM
BENCHMARKS
Benchmark
CRITICAL MASS
CRITICALITY
EIGENVALUES
EVALUATION
MOTORS
PLUTONIUM
PUMPING
Plutonium
REFLECTION
ROCKY FLATS PLANT
Rocky Flats
SAFETY MARGINS
STEELS
TANKS
THICKNESS
VALIDATION