Oxidative transformation of Tungsten (W) nanoparticles potentially released in aqueous and biological media in case of Tokamak (nuclear fusion) Lost of Vacuum Accident (LOVA)

Bernard Angeletti,Elodie Bernard,Dominique Vrel,Jerome Rose,Thierry Orsière,Bernard Rousseau,Chiara Uboldi,Nathalie Herlin,Christian Grisolia,Sarah Dine,Marcos Sanles Sobrido,Olivier Proux,Perrine Chaurand,Gheorghe Dinescu,Isabelle George,Véronique Malard,Romain Soulas

doi:10.5802/crgeos.41

Abstract

Oxidative transformation of Tungsten (W) nanoparticles potentially released in aqueous and biologicalmedia in case of Tokamak (nuclear fusion) Lost of Vacuum Accident (LOVA) technological breakthroughs need to be achieved before fusion become available and economically viable. In addition, and prior to industrial development of the fusion technology, it is worth addressing possible negative environmental and health impacts. For instance, the interactions between the plasma and refractory materials called plasma facing components (PFC) like tungsten, will generate tritiated dust. The aim of the study is to address the fate in water and biological media of W nanoparticles that might be released in case of Lost Of Vacuum Accident (LOVA). The dilution of particles in TRIS, LHC9 and pulmonary media did not strongly affect the average size of the particles while the dilution in Saline medium lead to substantial aggregation. The results proved that oxidative dissolution of W nanoparticles occurred in several aqueous/biological media (TRIS, LHC9 and Lung media) with increasing time. Fromthe different dissolution rates as a function of the tested media, it seems that the oxidative dissolutions are rate limited by diffusion in the oxidized layer surrounding the metallic core of particles. The mechanisms of dissolution involved W4A and W6A corroded layers prior to W6A dissolution. Knowledge provided by these dispersion–dissolution experiments helped to determine the environmental mobility and persistence as well as the bio-durability of these tungsten nanoparticles. As dissolution has potential to influence the toxicity of particles, it is a crucial parameter to consider in the risk assessment of particles.

Highlights

The world has to face a major energetic challenge in the years and various solutions to secure future energy supply that in the same time can minimize greenhouse gas emission, are developed
The aim of the study is to address the fate in water and biological media of W nanoparticles that might be released in case of Lost Of Vacuum Accident (LOVA)
The results proved that oxidative dissolution of W nanoparticles occurred in several aqueous/biological media (TRIS, LHC9 and Lung media) with increasing time

Summary

Introduction

The world has to face a major energetic challenge in the years and various solutions to secure future energy supply that in the same time can minimize greenhouse gas emission, are developed. Fusion energy has the capability to provide a sustainable solution to global energy needs. Upon many scientific and technological challenges of fusion, the selection of the refractory material needs to be improved. In the past, Tokamaks (nuclear fusion reactor) were operating with carbon refractory materials as plasma facing components (PFCs) to sustain the huge energy outflow. Due to large carbon erosion by deuterium plasma and to a large tritium trapping in carbon, huge quantity of tritium inventory was observed

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