Detecting Internal Hot Corrosion of In-service Turbine Blades Using Neutron Tomography with Gd Tagging

Sim, Cheul Muu; Oh, Hwa Suk; Kim, Tae Joo; Lee, Yoon Sang; Kim, Yi Kyung; Kwak, Seung Seob; Hwang, Young Ha

doi:10.1007/s10921-014-0244-x

Cited by 9 publications

(2 citation statements)

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“…Neutron imaging is a nondestructive examination technique that measures neutron transmission to examine a sample’s internal structure. This technique has been used in a variety of studies, including those of nuclear fuels and materials [ 1 , 2 , 3 , 4 , 5 , 6 ], cultural heritage objects [ 7 , 8 , 9 ], fuel cells [ 10 , 11 , 12 , 13 , 14 ], turbine blades [ 15 , 16 , 17 ], and many others. Digital neutron imaging techniques are now an essential capability for any state-of-the-art neutron imaging facility [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Boron-Based Neutron Scintillator Screens for Neutron Imaging

et al. 2020

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In digital neutron imaging, the neutron scintillator screen is a limiting factor of spatial resolution and neutron capture efficiency and must be improved to enhance the capabilities of digital neutron imaging systems. Commonly used neutron scintillators are based on 6LiF and gadolinium oxysulfide neutron converters. This work explores boron-based neutron scintillators because 10B has a neutron absorption cross-section four times greater than 6Li, less energetic daughter products than Gd and 6Li, and lower γ-ray sensitivity than Gd. These factors all suggest that, although borated neutron scintillators may not produce as much light as 6Li-based screens, they may offer improved neutron statistics and spatial resolution. This work conducts a parametric study to determine the effects of various boron neutron converters, scintillator and converter particle sizes, converter-to-scintillator mix ratio, substrate materials, and sensor construction on image quality. The best performing boron-based scintillator screens demonstrated an improvement in neutron detection efficiency when compared with a common 6LiF/ZnS scintillator, with a 125% increase in thermal neutron detection efficiency and 67% increase in epithermal neutron detection efficiency. The spatial resolution of high-resolution borated scintillators was measured, and the neutron tomography of a test object was successfully performed using some of the boron-based screens that exhibited the highest spatial resolution. For some applications, boron-based scintillators can be utilized to increase the performance of a digital neutron imaging system by reducing acquisition times and improving neutron statistics.

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Section: Introductionmentioning

confidence: 99%

Boron-Based Neutron Scintillator Screens for Neutron Imaging

et al. 2020

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“…Radiography measures the neutron transmission through a sample to non-destructively visualize its internal condition. Neutron radiography has been utilized in a multitude of applications including those of nuclear fuels [ 1 , 2 , 3 , 4 , 5 ], cultural heritage objects [ 6 , 7 , 8 ], and industrial applications such as fuel cells [ 9 , 10 , 11 , 12 , 13 ] and turbine blade analysis [ 14 , 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Measuring Thickness-Dependent Relative Light Yield and Detection Efficiency of Scintillator Screens

Chuirazzi

Craft

2020

J. Imaging

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Digital camera-based neutron imaging systems consisting of a neutron scintillator screen optically coupled to a digital camera are the most common digital neutron imaging system used in the neutron imaging community and are available at any state-of-the-art imaging facility world-wide. Neutron scintillator screens are the integral component of these imaging system that directly interacts with the neutron beam and dictates the neutron capture efficiency and image quality limitations of the imaging system. This work describes a novel approach for testing neutron scintillators that provides a simple and efficient way to measure relative light yield and detection efficiency over a range of scintillator thicknesses using a single scintillator screen and only a few radiographs. Additionally, two methods for correlating the screen thickness to the measured data were implemented and compared. An example 6LiF:ZnS scintillator screen with nominal thicknesses ranging from 0–300 μm was used to demonstrate this approach. The multi-thickness screen and image and data processing methods are not exclusive to neutron scintillator screens but could be applied to X-ray imaging as well. This approach has the potential to benefit the entire radiographic imaging community by offering an efficient path forward for manufacturers to develop higher-performance scintillators and for imaging facilities and service providers to determine the optimal screen parameters for their particular beam and imaging system.

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