Community Research and Development Information Service - CORDIS

Abstract

IT IS EXPECTED THAT DURING PLASMA DISRUPTIONS THE FIRST WALL OF A TOKAMAK REACTOR WILL BE EXPOSED TO EXTREMELY HIGH HEAT FLUXES. BY CALCULATION, IT HAS BEEN SHOWN THAT SURFACE MELTING AND EVAPORATION WILL TAKE PLACE. SIMULATION EXPERIMENTS HAVE BEEN CARRIED OUT USING ELECTRON GUNS, FOR EVALUATION OF THE LIFETIME OF THE FIRST WALL. ANALYTICAL AND NUMERICAL SOLUTIONS HAVE BEEN DEVELOPED FOR CALCULATING MELT DEPTH AS A FUNCTION OF THE MATERIAL CHARACTERISICS AND PLASMA DISRUPTION PARAMETERS, TAKING INTO ACCOUNT THE FORCED CONVECTION IN THE MELT ZONE. THE EXPERIMENTS SHOW THAT IT IS NECESSARY TO TAKE CONSIDERABLE CONVECTION IN THE MELT LAYER INTO ACCOUNT. THE RAPID SOLIDIFICATION OF THE MELT LAYER LEADS TO A CHANGE IN THE CRYSTALLINE STRUCTURE AND TO THE FORMATION OF CRACKS. ALLOYING ELEMENTS WITH A HIGH VAPOUR PRESSURE EVAPORATE PREFERENTIALLY. THE STRESSES GENERATED DURING COOLING SOMETIMES INDUCE PHASE CHANGES. DURING NEUTRON IRRADIATION HELIUM IS FORMED IN ALL FIRST WALL MATERIALS. THE FERROMAGNETISM FOUND IN DROPLETS AND STRUCTURAL MATERIAL OF THE LIMITER HAS BEEN EXPLAINED BY MICROSEGREGATION AND THE FORMATION OF FERRITE DURING RAPID COOLING.

Additional information

Authors: BROSSA F, JRC-ISPRA;CAMBINE M, JRC-ISPRA;QUATAERT D, JRC-ISPRA;RIGON G, JRC-ISPRA;SCHILLER P JRC-ISPRA, JRC-ISPRA
Bibliographic Reference: PAPER PRESENTED: 3RD INTERNATIONAL CONFERENCE ON FUSION REACTOR MATERIALS, KARLSRUHE/D, OCT. 4-8, 1987. JOURNAL OF NUCLEAR MATERIALS, VOLS. 155-157, PP 412-416, 1988
Record Number: 1989126218400 / Last updated on: 1989-04-01
Category: PUBLICATION
Available languages: en