CONSIDERATIONS ON BASIC REQUIREMENTS OF FUELING, PLASMA EXHAUST AND WALL CONDITIONING IN ITER

This paper presents considerations on basic requirements of fuelling, plasma exhaust and wall conditioning in ITER-EDA. In ITER-EDA, typical machine parameters are 1.5 GW of a fusion power and 1000 sec of a DT burn duration. Fuelling system consists of gas- and pellet injection s ystems. Maximum DT fuelling rate is 100 Pam(3)/s (pellet) to 500 Pam(3 )/s (gas). Impurity gas (e.g. Ne,Ar) will be also injected to control divertor radiation loss. In plasma exhaust, designed value of total ne utral pressure at inlet of pumping duct is 0.1 Pa to 10 Pa. Total net pumping speed of cryogenic primary pumps is about 300 m(3)/sec. In max imum, 90% of the regenerated fuel gases (H,D,T) from the primary cryop ump will be directly back into the plasma. In wall conditioning, glow discharge cleaning(GDC) and electron cyclotron resonance discharge cle aning(ECRDC) are considered.