@article{oai:repo.qst.go.jp:00081560,
 author = {Asakura, Nobuyuki and Hoshino, Kazuo and Homma, Yuuki and Sakamoto, Yoshiteru and Special Design Team for Fusion DEMO, Joint and Nobuyuki, Asakura and Yuuki, Homma and Yoshiteru, Sakamoto},
 journal = {Nuclear Materials and Energy},
 month = {Mar},
 note = {Handling of a large thermal power exhausted from the confined plasma is one of the most important issues for ITER and DEMO. A conventional divertor, which has the closed geometry similar to that of ITER and longer leg of 1.6 m, was proposed for the Japanese (JA) DEMO reactor (Rp/ap= 8.5/2.42 m). A radiative cooling scenario of Ar impurity seeding and the divertor performance have been demonstrated by SONIC simulation, in order to evaluate the power exhaust in JA-DEMO 2014 (primary design with Psep~283MW) and JA-DEMO with higher plasma elongation (a revised design with Psep~235MW). The divertor operation with the peak qtarget < 10MWm-2 was determined in the low nesep of 2-3x1019 m-3 under the severe conditions of reducing radiation loss fraction, i.e. f*raddiv = (Pradsol+Praddiv)/Psep, and diffusion coefficients (chi and D). The divertor geometry and reference key parameters (f*raddiv ~0.8, chi =1 m2/s and D = 0.3 m2/s) were so far consistent with the power exhaust concepts in the nesep range, and the revised JA-DEMO design has advantages of wider nesep range and enough margin for the divertor operation. For either severe assumption of f*raddiv~0.7 or chi and D to the half value, higher nesep operation was required for the primary design in order to control the peak qtarget < 10MWm-2, i.e. the operation window was reduced. Applying the two severe assumptions, the divertor operation was difficult in the low nesep range.},
 title = {Simulation studies of divertor detachment and critical power exhaust parameters for Japanese DEMO design},
 volume = {26},
 year = {2021}
}