Development of a research reactor protocol for neutron multiplication measurements

Arthur, Jennifer; Bahran, Rian; Hutchinson, Jesson D.; Sood, Avneet; Thompson, Nicholas; Pozzi, Sara A.

doi:10.1016/j.pnucene.2018.02.024

Cited by 11 publications

(13 citation statements)

References 6 publications

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“…Due to the absence of noticeable burnup, the fuel inside zero-power reactors is typically very well characterized, contrary to fuel from reactors with significant burnup, and allows entering the core for direct manipulation of experimental equipment. These considerations have been documented previously [25]. In addition, the RCF core is sufficiently large for spatial effects to be relevant for the purpose of the our experimental campaign, as supported by preliminary simulations.…”

Section: Experimental Setup and Numerical Experimentssupporting

confidence: 67%

“…High burnup of some research reactors can also preclude entering the core for direct manipulation of experiment equipment. These considerations have been documented previously [25]. In addition, it is beneficial for the system to be physically large; while it would be beneficial to have an even larger system than the RCF, it was determined via preliminary simulations that this reactor is large enough to meet the experiment objectives.…”

Section: Supplementary Materials E: Experimental Setupmentioning

confidence: 90%

“…The Walthousen Reactor Critical Facility (RCF) at Rensselaer Polytechnic Institute (RPI) is a zeropower education, research, and training reactor operated with 4.81% enriched UO 2 ceramic fuel with stainless steel [25]. The fuel has an active length of 36 inches and the fuel pins are arranged in a square lattice with a pitch of 0.64 inches.…”

Section: Experimental Setup and Numerical Experimentsmentioning

confidence: 99%

“…The NoMAD systems have been used for many neutron multiplicity measurements; most of these experiments have taken place at the National Criticality Experiments Research Center (NCERC) [52,26,49,43,42]. The NoMAD was previously used for subcritical measurements at the RCF [25]; lessons learned from that measurement campaign were utilized in the design of this experiment. Also placed in the core were four small 3 He detectors, shown in Figure ??.…”

Section: Supplementary Materials E: Experimental Setupmentioning

confidence: 99%

“…This interest motivated an international collaboration gathering LANL, IRSN and CEA, with three objectives: designing ad-hoc experiments and dedicated detectors to extract information on neutron fluctuations; developing Monte Carlo transport codes capable of filling the gaps of experimental measurements; and deriving a proper mathematical framework to interpret the obtained results. The experiments took place at the Reactor Critical Facility (RCF) [25] of Rensselaer Polytechnic Institute (RPI) over a week in August 2017 and were followed by the analysis of measured data and the Monte Carlo simulations. The main observables were temporal and spatial correlations in the neutron population, as well as their dependence on reactor power.…”

Section: Introductionmentioning

confidence: 99%

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Patchy snapshots of nuclear chain reactions

Dumonteil¹,

Bahran

Cutler

et al. 2020

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Stochastic fluctuations of the neutron population within a nuclear reactor are typically prevented by operating the core at a sufficiently high power. This regime, where the evolution of the neutron density is essentially deterministic, is key for automatic protection and safety systems to safely detect unwanted power excursions during an accident, and to rapidly initiate a reactor trip procedure in case it is needed. Recent works, supported by numerical simulations, have however reported that, for large reactors, the branching nature of the fission reactions might induce strongly non-Poissonian patterns in the neutron spatial distribution, and that stochastic fluctuations might still persist at reactor powers close to operating conditions (startup phase). An international program conducted by LANL, IRSN and CEA was therefore setup to experimentally detect and characterize such fluctuations and correlations. An experiment took place in 2017 at the Reactor Critical Facility (RCF) of the Rensselaer Polytechnic Institute (USA). In this paper we will report the main findings of this experimental program, supported by stochastic models and by the development of a dedicated high-fidelity Monte Carlo simulation code. We will in particular describe and explain the strong patchiness in neutron power distributions measured at the RCF, as well as a peculiar 'blinking' behavior of the core, and discuss the consequences of these findings on nuclear safety.

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Section: Experimental Setup and Numerical Experimentssupporting

confidence: 67%

Section: Supplementary Materials E: Experimental Setupmentioning

confidence: 90%

Section: Experimental Setup and Numerical Experimentsmentioning

confidence: 99%