This paper presents design considerations for gas and pellet fuelling
in ITER. Typical machine performance is 1.5 GW of fusion power for 100
0 s of DT burn. The fuelling system consists of gas and pellet injecti
on. The maximum DT fuelling rate is 500 Pa m(3)/s during a plasma dens
ity rise and 200 Pa m(3)/s during steady state DT burn. Impurity gas (
e.g. Ne, Ar) will also be injected to control divertor radiation losse
s. The plasma exhaust is designed for a neutral pressure of 0.1-10 Pa
at the inlet of the pumping duct Total net pumping speed of the cryoge
nic primary pumps is about 300 m(3)/s. Up to 90% of the regenerated fu
el gases (H,D,T) from the primary cryopump will be returned directly t
o the plasma. Copyright (C) 1996 Elsevier Science Ltd.