29th Symposium on Fusion Technology (SOFT 2016)

P3.115 Profile analysis of the first wall heat load required for demo blanket concept

7 Sep 2016, 11:00

1h 20m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 115

Poster F. Plasma Facing Components P3 Poster session

Speaker

Yuya Miyoshi (Japan Atomic Energy Agency)

Description

Understanding of the heat load profile on the first wall (1^stst wall) is one of the key issues to establish the DEMO blanket concept, because the thermal stress on the each blanket module depends on its surface heat load, and it will vary with the 1^stst wall shape, the toroidal/poloidal position and the plasma equilibrium. Thus, the 1^stst wall surface of the blanket module has to be designed according to the heat load profile on the 1^stst wall. One of the main factors of the heat load is plasma heat flux. Some of plasma particles in the SOL (Scrape Off Layer) region go to the first wall along the magnetic field line. It is known that this parallel heat flux by the plasma particle at the outboard mid-plane decays exponentially in the radial direction and its decay length depends on the connection length. In the divertor phase, the magnetic field line is divided by the first wall, i.e. the connection length and the decay length change. This effect makes it difficult to estimate the heat load. Here, the new calculation model has been developed. From the 2 dimensional magnetic field line trace data, the SOL region is divided into the several flux tube regions, and the decay length and the parallel heat flux in each region is calculated, and the heat load is estimated. In the case of R = 8.5m and fusion power is 1.4GW Japanese DEMO reactor, the heat load is peaked near the inboard baffle plate and its value is 0.9MW/m²2. In this presentation, we'll suggest the new 1^stst wall shape design concept which decreases the peak value of the 1^stst wall heat load from the more detailed analysis with the 3 dimensional magnetic field line trace data.