Fig. 2-16 Fuel processing system of fusion reactor

Table 2-3

Major results of Japan-US collaborative research on fusion fuel processing cycle using TSTA at the Los Alamos National Laboratory

Development of innovative technology developed ideas of advanced processing, success fully carried out fuel testing and operation of the tritium facility Development of fusion fuel processing system obtained data bases applicable to ITER design and planning of operational scenario Demonstration of the safe handling of tritium carried out tritium handling up to about 100 grams; processing of about 1 kg per day with extendedcontinuous operation for 25 days International collaboration experienced installation of JAERI's hardware (fuel cleanup system) at the US facility and combined experiments, "hot" operation of the facility and various safety approval procedures of the US authorities

To maintain fusion reactions or fusion burning in a fusion reactor, it is necessary to keep the reactor-core plasma always clean while being fueled by high purity deuterium and tritium fuels. For this purpose the supply of fuels to the core plasma and the removal of impurities from it should be done continuously. In general only a few % of injected fuels is burned up in the fusion reactor, the role of a fusion fuel processing system is very important; to recover and to clean up deuterium and tritium fuels from unburned exhaust gases from the reactor core and to re-inject the purified fuels continuously to the reactor core as illustrated in Fig. 2-16. The recovery and clean-up processes of tritium from the breeding blanket (the right loop in Fig. 2-16) are also important parts of the fuel processing system. To perform these operations efficiently, the fuel processing system is to be installed in the vicinity of the reactor itself and operated directly-coupled to the reactor. Tritium is a weakly radioactive gas, accordingly the safe handling technology of tritium, for example to prevent the leakage of fuels and exhaust gases from the fuel processing system (tritium confinement), should be developed and established to secure public acceptance of the fusion reactor. We have been conducting R&D on the tritium fuel processing cycle using the TSTA (Tritium Systems Test Assembly) at the Los Alamos National Laboratory under a Japan-US collaboration program. TSTA is the only existing simulated loop of the fusion fuel processing cycle of a fusion reactor capable of handling about 100 grams tritium. As summarized in Table 2-3, we have successfully demonstrated the fuel processing cycle for an extended continuous operation with a fuel flow rate of up to 1/5 of the planned ITER operation.

Reference S. Konishi, et al., Extended Operation of Reactor Scale Fusion Fuel Loop Under US-Japan Collaboration, Proc. 15th IEEE Symposium of Fusion Engineering, Oct. 11-15, 1993, Hyannis, Ma., 204.

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