# Assessment of the Runaway Electrons induced damage to the Tokamak First Wall

## TL;DR

This paper evaluates the damage caused by runaway electrons to tokamak first wall materials, comparing Beryllium and Tungsten, using simulations of electron impacts and thermal responses to understand damage mechanisms.

## Contribution

It introduces a combined simulation approach using FLUKA and finite element modeling to analyze runaway electron damage on tokamak first wall materials.

## Key findings

- Higher impact angles increase electron penetration and energy deposition.
- Runaway electron current influences the thermal response and melting of materials.
- Material damage varies significantly between Beryllium and Tungsten.

## Abstract

The study assessed the damage caused by Runaway Electrons (RE) on First Wall tiles, comparing the effects on Beryllium and Tungsten. This was done by using realistic RE energy distribution functions to replicate RE impacts through the FLUKA code. These energy distribution functions are based on the ASDEX Upgrade experiment # 39012. The parametric analysis carried out with FLUKA in the presence of magnetic fields indicated a clear relationship between the beam impact angle and the material deposited energy, demonstrating that higher impact angles lead to deeper electron penetration and greater deposited energies. A finite element model based on apparent heat capacity formulation in FreeFem++ was developed to analyze the material thermal response to such thermal loads using volumetric energy density profiles from FLUKA simulations as input. Different RE current values were simulated to show its influence on the evolution of the material temperature and melting thickness