Benchmark Evaluation of Plutonium Nitrate Solution Arrays

Conference · Mon Sep 19 00:00:00 EDT 2011

OSTI ID:1031662

Marshall, Margaret A. ^[1]; Bess, John D. ^[2]

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1. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
2. Idaho National Lab. (INL), Idaho Falls, ID (United States)

In October and November of 1981 thirteen approach-to-critical experiments were performed on a remote split table machine (RSTM) in the Critical Mass Laboratory of Pacific Northwest Laboratory (PNL) in Richland, Washington, using planar arrays of polyethylene bottles filled with plutonium (Pu) nitrate solution. Arrays of up to sixteen bottles were used to measure the critical number of bottles and critical array spacing with a tight-fitting Plexiglas® reflector on all sides of the arrays except the top. Some experiments used Plexiglas shells fitted around each bottle to determine the effect of moderation on criticality. Each bottle contained approximately 2.4 L of Pu(NO₃)₄ solution with a Pu content of 105 g Pu/L and a free acid molarity H+ of 5.1. The plutonium was of low ²⁴⁰Pu (2.9 wt.%) content. These experiments were performed to fill a gap in experimental data regarding criticality limits for storing and handling arrays of Pu solution in reprocessing facilities. Of the thirteen approach-to-critical experiments eleven resulted in extrapolations to critical configurations. Four of the approaches were extrapolated to the critical number of bottles; these were not evaluated further due to the large uncertainty associated with the modeling of a fraction of a bottle. The remaining seven approaches were extrapolated to critical array spacing of 3-4 and 4-4 arrays; these seven critical configurations were evaluation for inclusion as acceptable benchmark experiments in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1031662
• Report Number(s): INL/CON-11-21003; TRN: US1200149
• Resource Relation: Conference: 9. International Conference on Nuclear Criticality Safety (ICNC2011), Criticality Experiments, Edinburgh, Scotland (United Kingdom), 19-22 Sep 2011; Related Information: https://www.ans.org/meetings/view-120/
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
97 MATHEMATICAL METHODS AND COMPUTING
BENCHMARKS
CRITICAL MASS
CRITICALITY
CROSS SECTIONS
EVALUATION
IMPURITIES
NEUTRONS
NITRATES
PLEXIGLAS
PLUTONIUM
PLUTONIUM NITRATES
POLYETHYLENES
REPROCESSING
SAFETY
Nuclear Criticality Safety Program (NCSP)
critical experiment
plutonium solutions array
benchmark evaluation
remote split table machine (RSTM)