Innovative materials for fusion power plant structures: separating functions

Abstract

Fusion reactors create extreme conditions for structures close to the plasma. It seems unlikely that materials currently being considered can meet all performance requirements under such conditions. We explore the possibility of separating functionality in composite structures to overcome this barrier. To this end, several suggestions of directions are made for the search for such materials. In particular, we note some of the new materials that have become available only in the last two decades. Those discussed include the use of diamondlike carbon coatings, nano-structured materials, layered structures, stacked structures, and viscous coatings, including more complex carbon composite materials. Materials modelling will be an important component in the search for viable materials. However, the extreme conditions and the nature of the radiation damage demand extensions both to molecular dynamics and to the much-used Norgett-Robinson-Torrens model. We identify some of the relevant condensed matter challenges for modelling and materials testing in the fusion context, including the relevance of spallation source neutron testing to fusion materials evaluation.

Enthalpy Landscape Dictates the Irradiation-Induced Disordering of Quartz

“…Understanding irradiation-induced damage is of great importance for applications including nuclear waste immobilization, nuclear plant safety, and nuclear fuel form integrity, as well as for the controlled doping of semiconductors and in fusion reactors [1][2][3][4][5]. Irradiation induces the formation and accumulation of defects in crystals' atomic networks [1,6].…”

Interactions of diamond surfaces with fusion relevant plasmas

“…In addition, the edge plasma and the first-wall material constitute a strongly coupled system. From the current knowledge, tungsten and tungstenbased alloys have been presented as the only recognized option [1], although different innovative solutions have been proposed [2]. Another route favours the use of liquid metals (Li, Ga) but although the experimental results to date are encouraging [3], the use of large surfaces of liquid metals as PFM is technologically challenging.…”

Fusion power: a challenge for materials science

“…The current facilities for testing the effects of neutron irradiation are summarized by Stoneham et al (2004). They generally suffer from the disadvantage that the maximum recoil energies are well below that expected from 14 MeV neutrons and the gas production rate is around 50 times too low.…”

“…Stoneham et al (2004) suggest that composite materials could be designed in which the components have different functions. One example of such a material is ODS steel, which was discussed in §2.…”

“…The remainder of the divertor uses tungsten as a plasma-facing material, which is favoured because of its high melting temperature and thermal conductivity. Diamond has been suggested as an alternative to graphitic carbon as a possible divertor material (Stoneham et al 2004). Its exceptional thermal conductivity would be favourable for high thermal loads and its strong bonding should decrease its susceptibility to chemical erosion by hydrogen.…”