The EPQ Code System for Simulating the Thermal Response of Plasma-Facing Components to High-Energy Electron Impact

Journal Article · Tue Jun 15 00:00:00 EDT 2004 · Fusion Science and Technology

OSTI ID:20849707

Ward, Robert Cameron ^[1]; Steiner, Don ^[2]

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1. Los Alamos National Laboratory (United States)
2. Rensselaer Polytechnic Institute (United States)

The generation of runaway electrons during a thermal plasma disruption is a concern for the safe and economical operation of a tokamak power system. Runaway electrons have high energy, 10 to 300 MeV, and may potentially cause extensive damage to plasma-facing components (PFCs) through large temperature increases, melting of metallic components, surface erosion, and possible burnout of coolant tubes. The EPQ code system was developed to simulate the thermal response of PFCs to a runaway electron impact. The EPQ code system consists of several parts: UNIX scripts that control the operation of an electron-photon Monte Carlo code to calculate the interaction of the runaway electrons with the plasma-facing materials; a finite difference code to calculate the thermal response, melting, and surface erosion of the materials; a code to process, scale, transform, and convert the electron Monte Carlo data to volumetric heating rates for use in the thermal code; and several minor and auxiliary codes for the manipulation and postprocessing of the data. The electron-photon Monte Carlo code used was Electron-Gamma-Shower (EGS), developed and maintained by the National Research Center of Canada. The Quick-Therm-Two-Dimensional-Nonlinear (QTTN) thermal code solves the two-dimensional cylindrical modified heat conduction equation using the Quickest third-order accurate and stable explicit finite difference method and is capable of tracking melting or surface erosion. The EPQ code system is validated using a series of analytical solutions and simulations of experiments. The verification of the QTTN thermal code with analytical solutions shows that the code with the Quickest method is better than 99.9% accurate. The benchmarking of the EPQ code system and QTTN versus experiments showed that QTTN's erosion tracking method is accurate within 30% and that EPQ is able to predict the occurrence of melting within the proper time constraints. QTTN and EPQ are verified and validated as able to calculate the temperature distribution, phase change, and surface erosion successfully.

• OSTI ID: 20849707
• Journal Information: Fusion Science and Technology, Vol. 45, Issue 4; Other Information: Copyright (c) 2006 American Nuclear Society (ANS), United States, All rights reserved. http://epubs.ans.org/; Country of input: International Atomic Energy Agency (IAEA); ISSN 1536-1055
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANALYTICAL SOLUTION
BURNOUT
COMPUTERIZED SIMULATION
CONTROL
E CODES
EROSION
FINITE DIFFERENCE METHOD
FIRST WALL
HEATING RATE
MELTING
MEV RANGE
MONTE CARLO METHOD
NONLINEAR PROBLEMS
OPERATION
PHOTONS
PLASMA DISRUPTION
PLASMA SIMULATION
POWER SYSTEMS
RUNAWAY ELECTRONS
SURFACES
TEMPERATURE DISTRIBUTION
THERMAL CONDUCTION
THERMONUCLEAR REACTOR MATERIALS
TOKAMAK DEVICES