1. Neutronics Analysis for K-DEMO Blanket Module with Helium coolant June 26, 2013 Presented by Kihak IM Prepared by Y.S. Lee Fusion Engineering Center DEMO Technology Division / In-Vessel Component Team PPPL-NFRI Meeting, June 26-28, 2013, at PPPL

2. Thickness of Blanket Layers in the Current K-DEMO  Inboard Blanket [Thickness = 1,050 mm]  Outboard Blanket [Thickness = 1,200 mm] W Li 4 SiO 4 Cooling channel Be B4CB4C Structural Material W FW – 4 mm RAFM ~ 15 mm He Channel ~ 10 mm RAFM – 2 mm Ceramic pebble breeder 28 302 Manifold & Structures Shield Inb. Blanket 155 150 75 59 Be 31 FW Be 50 200 452 Manifold & Structures Shield 200 28 Outb. Blanket 155 150 75 59 Be 31 FW Be 50

3. Concept of Blanket (One Module) Cooling Channel  FW requires a dedicated cooling channel…. Maximum neutron wall load area The other 8 cooling channels, 6 mm wide each, have common inlet/outlet (Peak) 3 MW/m 2 neutron wall load + ~0.5 MW/m 2 radiation heat load (f core_rad = 0.5)

4. Neutronic Analysis Model for Inboard/Outboard Blanket (One Module) for Thickness Optimization between Layers Thickness of Layer (cm) Accumulated Thickness (cm) FW0.4 Cooling Channel2.7 (1.5+1.0+0.2) 3.1 1 st Breeder1.5 4.6 Cooling Channel1.2 (0.2+0.8+0.2) 5.8 2 nd Breeder2.0 7.8 Cooling Channel1.2 (0.2+0.8+0.2) 9.0 1 st Be15.0 24.0 Cooling Channel1.0 (0.2+0.6+0.2) 25.0 3 rd Breeder1.5 26.5 Cooling Channel1.0 (0.2+0.6+0.2) 27.5 4 th Breeder3.0 30.5 Cooling Channel1.0 (0.2+0.6+0.2) 31.5 2 nd Be15.5 47.0 Cooling Channel1.0 (0.2+0.6+0.2) 48.0 5 th Breeder3.0 51.0 Cooling Channel1.0 (0.2+0.6+0.2) 52.0 3 rd Be2.0 54.0 Cooling Channel0.8 (0.2+0.4+0.2) 54.8 100 54.8 3 MW neutron (max.) = 2.13x10 18 n/s [unit in cm] Shielding behind the breeding blanket is not included yet.

5. Neutronics Analysis  Accumulated TBR = 1.134 (for one module) 100 54.8 [unit in cm] Neutron Reflection B.C. at sides (Minor) Neutron penetration at back side Neutron Back-scattering at front (~10% ?) If neutron back-scattering at front is counted in, TBR could be increased by ~10% (?).  3D full sector model is required to get reliable TBR  3D sector model is under construction… NOT ENOUGH to meet global TBR >1, considering non-breeding zone, such as divertor and ports.

6. Generated Heat in the individual layer (for NWL = 3 MW) 3.3 MW (Energy multiplication factor = 1.1) Could be increased if back-scattered neutrons are counted in Be Li Breeder  Important data for cooling design Some heat generation in W and RAFM

7. Power density in the HCCB module Tungsten Li-breeder (exo-thermic reaction) Power density is higher in tungsten and Li-breeding zones

8. Future Work 100 54.8  Shielding will be added and optimized.  Model expansion is on-going to cover 3-D, 22.5 degree toroidal sector of both inboard and outboard blankets, to consider the reflected neutrons and global TBRs.  will give more reliable global TBR…  T-H analyses are on-going in parallel at the moment for appropriate cooling design.