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Title: Characterisation of the spatial variability of material properties of Gilsocarbon and NBG-18 using random fields

Journal Article · · Journal of Nuclear Materials

Graphite is a candidate material for Generation IV concepts and is used as a moderator in Advanced Gas-cooled Reactors (AGR) in the UK. Spatial material variability is present within billets causing different material property values between different components. Variations in material properties and irradiation effects can produce stress concentrations and diverse mechanical responses in a nuclear reactor graphite core. In order to characterise the material variability, geostatistical techniques called variography and random field theory were adapted for studying the density and Young's modulus of a billet of Gilsocarbon and NBG-18 graphite grades. Variography is a technique for estimating the distance over which material property values have significant spatial correlation, known as the scale of fluctuation or spatial correlation length. The paper uses random field theory to create models that mimic the original spatial and statistical distributions of the original data set. This study found different values of correlation length for density and Young's modulus around the edges of a Gilsocarbon billet, while in the case of NBG-18, similar correlation lengths where found across the billet. Furthermore examples of several random fields are given to reproduce the spatial patterns and values found in the original data.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1479781
Alternate ID(s):
OSTI ID: 1635890; OSTI ID: 22752316
Journal Information:
Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Journal Issue: C Vol. 511; ISSN 0022-3115
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (1)

A Review of Finite Element Method Models for Nuclear Graphite Applications journal December 2018