ITER (International Thermonuclear Experimental Reactor) is the world’s largest and most influential international scientific research project of exploiting and utilizing nuclear fusion energy, with the aim to verify the scientific and technical feasibility in the peaceful use of fusion energy. A Tritium Breeding Blanket (BB) ensuring tritium breeding self-sufficiency is a compulsory component for demonstration power reactor (DEMO), the next-step after ITER, although is not present in ITER. Mock-ups of DEMO BB, called Test Blanket Modules (TBMs), will be inserted and tested in ITER directly facing the plasma. They are the principal means by which ITER will provide the first experimental data on the performance of the BBs that is still an open issue on the path to commercial fusion power. These activities correspond to the so-called “TBM Program”. Amongst ITER’s three engineering goals, the overall objective of the TBM Program is to acquire all relevant data and information concerning a given breeding blanket in order to validate the applied codes for the relevant analyses and to be able to design, to manufacture and to operate a BB-system in DEMO and in following fusion power reactors, provided that data on long-term irradiation effects and failure modes are obtained in parallel in other facilities.
Since 2004, China carried out a series of TBM-related activities, and decided, in 2009, to adopt HCCB TBM (Helium Cooled Ceramic Breeder Test Blanket Module)—using high-temperature and high-pressure helium as coolant, Li4SiO4 ceramic pebble bed as tritium breeder, beryllium pebble bed as neutron multiplier, and reduced activation ferritic/ martensitic steels as structural material. HCCB TBM consists of TBM-set, HCS (Helium Cooling System), TES (Tritium Extraction System), TAS (Tritium Accountancy System), CPS (Coolant Purification System), NAS (Neutron Activation System), I&C (Instrumentation and control system) and so on.
According to ITER Organization (IO) arrangement, TBM will be implemented in following phases: design phase, manufacturing phase, transport and delivery to ITER site and on-site-test phase, commissioning and operating phase, and postprocessing phase. In February, 2014, China International Nuclear Fusion Energy Program Execution Center (CN DA) and IO officially signed the TBMA—HCCB TBM Agreement. According to the agreement, TBM implementation is arranged until the delivery phase, and tasks of other phases will be specified otherwise in a supplemental agreement. In September, 2015, CN HCCB TBM was the first one to have passed ITER TBWG’s conceptual design review (CDR). At the beginning of 2016, HCCB TBM Program officially launched the preliminary design, and now it is in the Preliminary Design phase.
Through participating in TBM Program and designing, manufacturing and testing test blanket systems, China will improve the capability of designing and manufacturing fusion reactor tritium breeding blankets and master critical engineering technologies such as design, material development, manufacture, operation, measurement, tritium-related technologies and energy extraction of fusion reactor tritium breeding blankets. And more importantly, China will cultivate high-level scientific research talents and lay a solid technical and talent foundation for the independent design and building of DEMO fusion reactors.
HCCB TBM layout configuration