Wall erosion and material transport to the Mark I carbon divertor of JET

Erosion and deposition at the vessel walls of the main chamber of JET were measured with lone term samples during the whole operation period of the Ma rk I carbon divertor from April 1994 until March 1995. Assuming toroidal sy mmetry, about 70 g Ni + Cr + Fe was found to be eroded from the inner torus wall and about 55 g Be from the outer torus wail due to sputtering by ener getic charge-exchange neutrals. Deposition has been measured on a poloidal section of the Mark I C divertor and on tiles from the inner and outer wall limiters. Eroded material is redeposited in the divertor and in the main c hamber where it is found predominantly at the sides of the poloidal limiter s and at the outer vessel wall. At these deposition-dominated areas in tota l about 25 g Ni + Cr + Fe, 28 g Be and 370 g C are found. The carbon origin ates mostly from the carbon limiters, additionally some may be originating from the divertor plates. (C) 1999 EIsevier Science B.V. All rights reserve d.