Tungsten is a promising candidate for plasma-facing materials to cover
the surface of the divertor plate in the design of the International
Thermonuclear Experimental Reactor (ITER). The Japan Atomic Energy Res
earch Institute (JAERI) has developed divertor mock-ups coated with tu
ngsten using the chemical vapor deposition (CVD) technique. Thermal fa
tigue and screening tests of ITER-relevant divertor mock-ups carried o
ut in an electron beam gun facility are presented. The two mock-ups co
nsist of a 2 mm thick CVD tungsten layer on heat sinks made of OFHC-Cu
and 30 wt.% Cu-infiltrated tungsten, respectively. The cooling channe
l is equipped with a twisted tape as heat transfer enhancement. Both m
ock-ups successfully withstood a steady-state deposited heat flux of 5
MW m(-2) for 1000 cycles. These experiments show that CVD W-coated di
vertor mock-ups meet ITER requirements for plasma-facing components. T
hese tests also demonstrate the capability of these mock-ups to withst
and a transient deposited heat flux of 22 MW m(-2) for 10 s without fa
ilure. (C) 1998 Published by Elsevier Science S.A. All rights reserved
.