بررسی اجمالی تحقیق و توسعه TBM در ژاپن

In Japan, development of Water Cooled Ceramic Breeder (WCCB) blanket is being performed as the primary candidate of Test Blanket Module (TBM) toward DEMO. Also development of high temperature Li–Pb blanket, Li/V blanket and Flibe blanket are being performed toward the advanced DEMO blanket. Regarding the WCCB TBM development, real scale First Wall (FW) was fabricated using Reduced Activation Ferritic Martensitic Steel (RAFMS), F82H and successfully tested by heat flux equivalent to ITER TBM condition, 0.5 MW/m2, 80 cycles with the same coolant condition as DEMO. Also, real scale Side Wall (SW) and real scale breeder pebble bed structure are successfully fabricated. Furthermore, asemmbling test of the real scale FW plate mockup and SW plate mockup was performed to clarify the welding condition to form TBM box structure. All key technologies of blanket module fabrication has been addressed and almost achieved toward TBM. Regarding the development of liquid breeder blankets, all key technologies, such as, material compatibility and mass transfer, tritium recovery performance, insulation coating development, were covered, by using elementary experiments to convection loops of Li–Pb, Li and Flibe. High temperature heat exchange test up to 900 °C has been initiated by using Li–Pb test loop.

In Japan, ceramic breeder blankets are developed as a primary option of the DEMO blanket. Also, liquid breeder blankets are developed as potential options for the advanced DEMO blanket. In the development strategy of Japan toward the DEMO blanket, Test Blanket Module (TBM) test program in ITER is regarded as one of the most important milestones, by which integrity of candidate blanket concepts and structures will be qualified by the same scale as DEMO blanket module in a real fusion environment in ITER. In the TBM program, Japan is proposing to test the Water Cooled Ceramic Breeder (WCCB) TBM as the primary candidate blanket. Also, Japan has a position to participate testing of other types of TBMs, such as liquid breeder blankets and helium cooled ceramic breeder blankets. For the TBM testing in the real fusion environment in ITER, it will be required to clear milestones to demonstrate the consistency with ITER design and ITER safety requirements, and the integrity of the TBM and its systems, prior to the installation in ITER. Milestones of ITER TBMs prior to the installation consist of milestones on safety assessment, module qualification and design integration in ITER. Japan Atomic Energy Agency (JAEA) is performing the development of fabrication technologies and design and safety assessment for the WCCB TBM with a collaboration of universities and National Institute for Fusion Science (NIFS). Currently, the engineering R&Ds and design and safety work are being performed, on the basis of well accumulated element technologies, aiming at the verification of TBM milestones and initiation of testing of the WCCB TBM in ITER in earliest timing of ITER operation. Regarding the liquid breeder blankets, universities and NIFS are performing development of key technologies for all of Li–Pb blankets, Li based blankets and Flibe blanket, aiming at the establishment of advanced DEMO blanket concepts and potential participation to the TBM testing program. Currently, the technology development of liquid breeder blankets in Japan is showing significant progress by scientific research and proceeding to the engineering scale loop tests. This paper overviews the recent achievements of R&Ds of the WCCB TBM and liquid breeder blankets in Japan.

Japan is performing the development of Water Cooled Ceramic Breeder Blanket Test Blanket Module as a primary option. As advanced blanket options, the development of liquid breeder blankets are performed. 2. Fabrication technology development of WCCB TBM is progressing in Real Scale Mockup – A near full scale TBM first wall mock-up has been successfully fabricated. By high heat flux test, the initial integrity under ITER equivalent surface heat flux was demonstrated (0.5 MW/m2 × 80 cycles, cooled by 15 MPa, 300 °C). – Full scale breeder bed box was successfully fabricated. – Full scale Side Wall was successfully fabricated. Assembling test with FW was performed. 3. Essential blanket technologies are being steadily developed, such as breeder and multiplier material development, neutronics technology, tritium technology and structural material development. 4. Development of liquid blankets are showing steady progress on key development items by elementary research and engineering scale loop tests, covering all kinds of liquid blankets, high temperature Li–Pb blanket, Li/V blanket and Flibe blanket.