Characterization of a Neutron Beam Following Reconfiguration of the Neutron Radiography Reactor (NRAD) Core and Addition of New Fuel Elements

et al. 2021

QuBS

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The Neutron Radiography Reactor at Idaho National Laboratory (INL) has two beamlines extending radially outward from the east and north faces of the reactor core. The control rod withdrawal procedure has recently been altered, potentially changing power distribution of the reactor and thus the properties of the neutron beams, calling for characterization of the neutron beams. The characterization of the East Radiography Station involved experiments used to measure the following characteristics: Neutron flux, neutron beam uniformity, cadmium ratio, image quality, and the neutron energy spectrum. The ERS is a Category-I neutron radiography facility signifying it has the highest possible rank a radiography station can achieve. The thermal equivalent neutron flux was measured using gold foil activation and determined to be 9.61 × 106 ± 2.47 × 105 n/cm2-s with a relatively uniform profile across the image plane. The cadmium ratio measurement was performed using bare and cadmium-covered gold foils and measured to be 2.05 ± 2.9%, indicating large epithermal and fast neutron content in the beam. The neutron energy spectrum was measured using foil activation coupled with unfolding algorithms provided by the software package Unfolding with MAXED and GRAVEL (UMG). The Monte-Carlo N-Particle (MCNP6) transport code was used to assist with the unfolding process. UMG, MCNP6, and measured foil activities were used to determine a neutron energy spectrum which was implemented into the MCNP6 model of the east neutron beam to contribute to future studies.

Section: Introductionmentioning

confidence: 99%

Neutron Beam Characterization at Neutron Radiography (NRAD) Reactor East Beam Following Reactor Modifications

Giegel

et al. 2021

QuBS

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“…The neutron beam flux was measured using foil activation methods [7]. An array of 21 gold foils was activated in the TREAT neutron beam for 3 hours with the reactor power of 80 kW.…”

Section: Beam Characterizationmentioning

confidence: 99%

“…An array of 21 gold foils was activated in the TREAT neutron beam for 3 hours with the reactor power of 80 kW. The resulting activity was measured using a calibrated high-purity germanium detector, then the activity at the end of exposure in the neutron beam was calculated based on this measurement, the decay constant, and the time between the measurement and end of exposure [7][8]. The measured average thermal equivalent neutron flux at the image plane is 8.25×10 6 ± 1.89×10 5 n/cm 2 s with the reactor power at 80 kW.…”

Section: Beam Characterizationmentioning

confidence: 99%

Reactivation of the Transient Reactor Test (TREAT) Facility Neutron Radiography Program

Jensen

Neutron Radiography - WCNR-11

et al. 2020

The TREAT radiography system is used to perform neutron radiography of fuels, experiments, and other specimens before and after irradiation within the TREAT reactor. The TREAT neutron radiography facility performed approximately 5,000 radiographs by the spring of 1977. Originally built in 1958, the TREAT Facility was in operation until it was placed in a shutdown status in 1994. Following the Fukushima incident and seeing a need for enhanced accident tolerant fuels, the United Stated Department of Energy decided to restart the TREAT facility and resume transient operations. In November 2017, the TREAT reactor was successfully restarted and is currently performing operational testing in preparation for initial experiment irradiations and transient testing. This paper discusses efforts to reactivate the TREAT neutron radiography facility. To characterize the neutron beam, gold foil activation measurements were made to determine an average neutron flux and flux profile. An open beam image provides the information about variations in the beam profile. A series of system qualification radiographs have been acquired to determine the effective image acquisition parameters, resulting image quality, and the relationships between the two.

“…Several exposures were taken with film and nCR for evaluation, see Figure 5. Images of the sensitivity indicator exhibit a Category-I facility according to ASTM E-545 [3,4] D3-SC Film RTP Image, Thermal Neutron Energy, from Dysprosium Transfer Foil nCR Blue Plate RTP Image, Thermal Neutron Energy, from Dysprosium Transfer Foil Figure 5 Resolution Test Piece It is important to note that the transfer method of irradiated nuclear fuels requires shielding and confinement. These factors determine the maximum resolution possible for the given system due to geometric unsharpness.…”

Section: Neutron Computed Radiography Of Irradiated Fuelmentioning

confidence: 99%

Conversion from Film Based Transfer Method Neutron Radiography to Computed Radiography for Post Irradiation Examination of Nuclear Fuels

Neutron Radiography - WCNR-11

2020

The Idaho National Laboratory supports multiple programs that are actively developing, testing, and evaluating new nuclear fuels including advanced commercial nuclear fuels, accident tolerant fuels, reduced-enrichment research reactor fuels, transmutation fuels, and advanced reactor fuels. Post irradiation examinations (PIE) of nondestructive and destructive techniques are performed at INL to research nuclear fuel behavior and performance under various conditions. The Neutron Radiography Reactor (NRAD) at INL is utilized to perform nondestructive examinations of irradiated nuclear fuels and the results of these examinations are used to aid in the decision making process for subsequent destructive exams. NRAD has historically performed transfer method neutron radiography with film as the imaging medium. This paper documents the effort to convert from film to computed radiography for PIE. Equipment selection, system characterization, and testing were performed as part of phase I. Phase II, as described in this paper, focuses on determining image resolution of the computed radiography system.