Development of a Research Reactor Protocol for Neutron Multiplication Measurements

Journal Article · Fri Jul 01 04:00:00 EDT 2016 · Transactions of the American Nuclear Society

OSTI ID:23042746

Bahran, R.; Hutchinson, J.; Sood, A. ^[1]; Arthur, J. ^[1]; Caracappa, P.; Thompson, N. ^[2]; Pozzi, S. ^[3]

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1. Los Alamos National Laboratory, Los Alamos, NM, 87544 (United States)
2. Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States)
3. University of Michigan, Ann Arbor, MI 48109 (United States)

Establishing a protocol for measurements on research reactors is the next step in advanced subcritical neutron multiplication inference measurements. Such measurements can help identify deficiencies and quantify uncertainties in nuclear data and validate predictive Monte Carlo radiation transport simulation capabilities related to subcritical neutron multiplication inference techniques. This work expands on previous benchmark-quality efforts performed at the National Criticality Experiments Research Center (NCERC) located in Nevada, including subcritical experiments with a 4.5-kg {alpha}-phase plutonium sphere surrounded by copper, tungsten and nickel. Evaluations of the nickel and tungsten measurements have both been accepted into the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook. The nickel benchmark was the first ICSBEP-accepted evaluation of measurements using the Feynman Variance-to-Mean method based on the Hage-Cifarelli formulism, and was the culmination of many years of subcritical experiment research. To help establish a protocol for research reactor-based subcritical measurements, a series of Critical and Subcritical {Phi}-Power Experiments at Rensselaer (CaSPER) have been designed. This neutron multiplication measurement series will be executed at the Rensselaer Polytechnic Institute Walthousen Reactor Critical Facility (RPI-RCF) in upstate New York. The RPI reactor facility can provide benchmark-quality integral experimental configurations where different reactivity states can be achieved by varying the control rod height/water height in the reactor. The diversity of achievable configurations are also unique in contrast to previous subcritical benchmark measurements in that they are spatially complex, involve different materials (fuel, moderator), and are characterized by system-specific neutron cross section sensitivities (various energy ranges and neutron reaction contributions). It is worth noting that previous proof-of-concept subcritical measurements have been performed on thermal systems at NCERC, at a variety of reactivity states by separation distance, yet it was not possible to know the reactivity of various configurations accurately for benchmarking (there are no control rod worth curves as there are no control rods). (authors)

• OSTI ID: 23042746
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 115; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BENCHMARKS
COMPUTERIZED SIMULATION
CONTROL ELEMENTS
CONTROL ROD WORTHS
COPPER
CRITICALITY
CROSS SECTIONS
ENERGY RANGE
MODERATORS
MONTE CARLO METHOD
NEUTRON REACTIONS
NEUTRONS
NICKEL
PLUTONIUM
RADIATION TRANSPORT
REACTIVITY
REACTOR SAFETY
RESEARCH REACTORS
SENSITIVITY
TUNGSTEN