ITER fuel cycle R&D: Consequences for the design

The ITER fuel cycle is designed to handle considerable flow rates of tritium with high flexibility and reliability; experimental work is ongoing to validate these designs. Cryo-pumping systems for torus exhaust and neutral beam injectors have been tested to confirm fast regeneration scenarios and to reduce the accumulation of semi-permanent inventories of tritiated impurities. A 1:1 prototype of the torus exhaust cryo-pump is going to be manufactured and extensively tested. Tritium compatible mechanical pumps are being developed, in which leak rates to the exterior and contact between tritiated gases and lubricating oil have been minimized. Comprehensive integrated tests with the three-step process for torus exhaust processing were carried out. An ITER scale prototype fast delivery, self-assay storage bed has been developed; this component is designed to maximize the ratio of delivery rate to stored inventory and is undergoing testing. An integrated concept for the isotope separation (ISS) and water detritiation (WDS) systems has been developed and is being tested on relevant scale; this will provide an additional decontamination step for the potentially tritiated protium reject from the ISS. Extensive use of computer modeling to study the dynamic behavior of these and other fuel cycle systems is made.