Conversion from Film to Image Plates for Transfer Method Neutron Radiography of Nuclear Fuel

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.

Section: Treat Neutron Radiography Program and Facility Descriptionmentioning

confidence: 99%

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

Jensen

Craft

Papaioannou

et al. 2020

“…Neutron radiography provides more comprehensive information about the internal geometry of irradiated nuclear fuels and components than any other nondestructive examination technique to date [1]. Transfer method neutron radiography can be used to study irradiated materials despite the very high gamma radiation fields emitted from them [2,3,4]. In the transfer method, a cassette of converter foils is placed in a neutron beam behind an object and exposed to the neutron beam.…”

Section: Introductionmentioning

confidence: 99%

“…The activated foils are coupled to an imaging medium (e.g. film [2], image plates [3]), which are exposed by the decay radiation as the foil decays. Another technique is to use image plates containing dysprosium [4].…”

Section: Introductionmentioning

confidence: 99%

Gamma Discriminating Scintillation Screens for Digital Transfer Method Neutron Imaging

Craft

Lehmann

Chuirazzi

et al. 2020

A collaborative project between Idaho National Laboratory (INL) and Paul-Scherrer Institute (PSI) is investigating a new type of scintillation screen that uses ZnS scintillator material with a dysprosium neutron converter instead of traditional prompt converters such as 6 Li. Such a screen exposed to a neutron beam creates a latent image by neutron activation of the dysprosium in the scintillator screen. The activated screen is transported into a camera box allowing the camera to read a digital image from the photons emitted by the activated scintillation screen. Such an imaging system combines modern camera-based system architecture with the approach of traditional indirect transfer method radiography. The results show for the first time that the combination of dysprosium with a scintillation material like ZnS can produce light which is measurable under common camera-based detection conditions and that neutron radiographic images of reasonable quality can be produced. The resolution was poorer than expected at ~ 300 μm, but is on the order of the desired resolution of 100 μm. Potential improvements and additional converter materials may be investigated in the future that could increase the light output and improve spatial resolution.

“…The construction of the NRAD reactor in 1978 included two neutron beamlines specifically designed for neutron radiography of irradiated nuclear fuels [3]. All three neutron radiography beamlines (two at NRAD and one at TREAT) use the indirect radiography methods, where a cassette of different foils is placed in the beamline and activated, then removed and placed next to either film or image plates to render an image [2,4]. The indirect method is not sensitive to gamma rays but is time-consuming.…”

Section: Introductionmentioning

confidence: 99%

First Neutron Computed Tomography with Digital Neutron Imaging Systems in a High-Radiation Environment at the 250 kW Neutron Radiography Reactor at Idaho National Laboratory

Papaioannou

Smolinski

Chuirazzi

et al. 2020