Session: CS-15-03 Mechanical Properties of Nuclear Graphite and Their Implementation in Codes and Standards (Joint with MF-29) – 3

Paper Number: 106760

106760 - Porosity Characterization in Nuclear Graphite 

Graphite is a critical component of nuclear reactors since the early days of nuclear power, and it continues to be the frontrunner for neutron moderation and structural support in Generation IV very high temperature reactors (VHTRs) and molten salt reactors (MSRs). Several grades of synthetic nuclear graphite are currently available; the different manufacturing techniques that are employed result in noticeable differences in the microstructure. One of the most distinguishing features of a certain grade is its porosity. It may be formed during the manufacturing phase (initial mixing or cooldown phases) or in a reactor operating under high temperatures. Although the pores have different sizes, shapes, and morphology characteristics, they are not always delineated in detail. In this work, pore features such size, shape, distribution, solidity, connectivity and orientation are extracted from high-resolution X-ray computed tomography (X-CT) scans of samples from four different grades of nuclear graphite (AXF/ZXF-5Q, IG-110 and NBG-18). After thresholding the images, the pore space is segmented into uniquely identifiable pores. Of particular interest, are the differences in the pore structure and connectivity between the poco grades (AXF/ZXF), which do not have a binder phase, relative to IG-110 and NGB-18 grades that are typically investigated for nuclear applications.

Presenting Author: Dina ElGewaily North Carolina State University

Presenting Author Biography: Dina ElGewaily is a PhD student in her 4th year, in NC State University, working with Dr. Jacob Eapen on two main nuclear materials characterization projects funded by the DOE. The first is concerned with the damage inflicted on SiC cladding in accident conditions due to steam attack, while the other projects investigate the diffusion and transport mechanisms of different fission products in nuclear-grade graphites as well as modeling their porosity.

Authors:

Dina ElGewaily North Carolina State University
Arash Rabbani University of Leeds
Jacob Eapen North Carolina State University