NSUF - Nuclear Science User Facilities

Neutron powder diffraction and transmission in graphite to assess impact of microstructure on neutron thermalization

Full Details
Principal Investigator
Name:
Ayman Hawari
Email:
nsuf@inl.gov
Phone:
(208) 526-6918
Team Members:
Name: Institution: Expertise: Status:
Ayman Hawari North Carolina State University radiation damage, Positron annihilation spectroscopy, Neutron beams, neutron physics Faculty
Scott Lassell North Carolina State University Plan experiments Other
Qingsheng Cai North Carolina State University Execute experiments Other
Experiment Details:
Experiment Title:
Neutron powder diffraction and transmission in graphite to assess impact of microstructure on neutron thermalization)
Work Description:
In this project, various samples of graphite and carbon materials will be irradiated for 3-4 months at the PULSTAR reactor to a total fast neutron fluence exceeding 1E18 n/cm2. Initially, the samples will be cut in forms suitable for diffraction and transmission measurements. After irradiation, the irradiated samples (along with unirradiated samples) will be examined using neutron powder diffraction and transmission measurements to produce structure factor, atomic pair distribution function, and transmission probability information. All work will performed at low temperatures (i.e., at or near room temperature).
Abstract
Several advanced nuclear reactor concepts have been proposed in the past few years including the Advanced High Temperature Reactor (AHTR), and the Fluoride Salt Cooled High Temperature Reactor (FHR), where thermal neutrons drive the fission reaction in a core that is primarily composed of graphitic/carbon materials. In this project, neutron powder diffraction and transmission measurements will be performed for three types of graphite materials that include nuclear graphite, carbon-carbon composites, and foam graphite. The structure factor and corresponding atomic pair distribution function will be measured along with thermal neutron transmission. The measurements will be correlated to inform the theory and simulations of neutron thermalization in graphite materials. Irradiated and unirradiated samples will be used in this work. Irradiations and measurements will be performed at the North Carolina State University (NCSU) PULSTAR reactor and associated facilities.

About Us

The Nuclear Science User Facilities (NSUF) is the U.S. Department of Energy Office of Nuclear Energy's only designated nuclear energy user facility. Through peer-reviewed proposal processes, the NSUF provides researchers access to neutron, ion, and gamma irradiations, post-irradiation examination and beamline capabilities at Idaho National Laboratory and a diverse mix of university, national laboratory and industry partner institutions.

Privacy and Accessibility ยท Vulnerability Disclosure Program