Study of poisoning effects with the ITER model pump during relevant operation cycles

Within the European research activities for the ITER fusion reactor, at the Forschungszentrum Karlsruhe (FZK) a test bed for the half-scaled ITER cryosorption pump was installed to study all the operational modes of interest. Following an extensive test program under ITER-like throughput conditions, additional studies were performed to assess the influence of liquid impurities on the sorption behaviour. After an extensive test program could already be successfully carried out the influences of liquid impurities on the pump performance should be studied. Tests with both water-like impurities and different tracer candidates were used during ITER-relevant operation cycles. Independent of the different tested impurities it could be proved that all requirements for the primary ITER torus vacuum pumps can be fulfilled with the actual vacuum pump concept. The total test program demonstrated that the adopted design concept meets all the ITER pumping requirements.