Diagnostic components in harsh radiation environments: Possible overlap in R&D requirements of inertial confinement and magnetic fusion systems

Abstract

The next generation of large scale fusion devices--ITER/LMJ/NIF--will require diagnostic components to operate in environments far more severe than those encountered in present facilities. This harsh environment is the result of high fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiation, and in some cases, debris and shrapnel, at levels several orders of magnitude higher than those experienced in today's devices. The similarities and dissimilarities between environmental effects on diagnostic components for the inertial confinement and magnetic confinement fusion fields have been assessed. Areas in which considerable overlap have been identified are optical transmission materials and optical fibers in particular, neutron detection systems and electronics needs. Although both fields extensively use cables in the hostile environment, there is little overlap because the environments and requirements are very different.

Origin of the visible absorption in radiation-resistant optical fibers

“…The optical components employed in the nuclear power plants or facilities devoted to the fusion studies [1] are exposed to a high level of radiation (neutrons and γ-rays) and operate at high temperatures (up to 700 • C). Such a harsh combined environment influences the performances of the optical fibers.…”

Potential common radiation problems for components and diagnostics in future magnetic and inertial confinement fusion devices

“…Four possible areas have been indicated where collaboration on diagnostic systems preparations could be of mutual benefit, namely optical components (fibres, windows, and mirrors), MI (mineral insulated) cables, electronics, and neutron diagnostics [5]. Of these, the most relevant common issue is the numerous optical transmission components, in particular windows and fibres, required for diagnostics in the case of MC, and for both operation and diagnostics for IC.…”

First principles study of oxygen vacancy defects in amorphous SiO2

“…A better understanding of the physical properties of these defects should contribute to the success of photonics and semiconductor industries. [1][2][3] In a-SiO 2 , the most important and studied radiation-induced point defects are the E centers. Based on the electron paramagnetic resonance (EPR) experiments, four kinds of paramagnetic point defects, such as E α , E β , E γ and E δ , have been distinguished in bulk materials.…”

“…The dimer configurations have the lowest thermodynamic charge-state levels, and the puckered 4× configurations have the highest thermodynamic charge-state levels among the five types of configurations. This work is of benefit to identifying and controlling the oxygen defects in a-SiO 2 …”