Effects of Neutron Radiation on the Thermal Conductivity of Highly Oriented Pyrolitic Graphite

TL;DR

This study investigates how 14 MeV neutron radiation affects the crystalline structure and thermal conductivity of Highly Ordered Pyrolytic Graphite (HOPG), crucial for nuclear target applications, revealing structural disruptions lead to altered heat dissipation properties.

Contribution

It provides new insights into the radiation-induced structural changes in HOPG and their impact on thermal conductivity, informing its use in nuclear technology.

Findings

Neutron irradiation causes structural disruptions in HOPG.

Altered crystalline structure affects thermal conductivity.

Results help determine HOPG's lifespan as a heat sink in nuclear environments.

Abstract

Highly Ordered Pyrolytic Graphite (HOPG) has been extensively researched due to its chemical and physical properties that make it suitable for applications in several technologies. Its high thermal conductivity makes HOPG an excellent heat sink, a crucial characteristic for manufacturing targets used in nuclear reactions, such as those proposed by the NUMEN project. However, when subjected to different radiation sources, this material undergoes changes in its crystalline structure, which alters its intended functionality. This study examined HOPG sheets before and after exposure to a 14 MeV neutron beam. Morphological and crystallographic analyses reveal that even minor disruptions in the high atomic ordering result in modifications to its thermal properties. The results of this study are essential to establish the survival time of the HOPG used as thermal interface material to improve heat dissipation of a nuclear target to be bombarded by an intense high-energy heavy-ion beam.