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US/JP Workshop on Fusion Power Plants and Related Advanced Technologies 23 th -24 th Feb. 2010 at UCSD, U.S.A. Design study of advanced blanket for DEMO reactor. JAEA Hiroyasu Utoh. Outline. Water-cooled LiPb BLK 2-D BLK analysis code He cooling system. 1. Introduction. PPCS (modelC).
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US/JP Workshop on Fusion Power Plants and Related Advanced Technologies 23th-24th Feb. 2010 at UCSD, U.S.A. Design study of advanced blanket for DEMO reactor JAEA Hiroyasu Utoh Outline • Water-cooled LiPb BLK • 2-D BLK analysis code • He cooling system
1 Introduction PPCS (modelC) SlimCS To discuss DEMO reactor design widely, the comparing investigation of BLK options is important.
2 Blanket has “trade-off” problems • First priority must be given to TBR because self-sufficient fuel supply is necessary in a fusion DEMO reactor. • However, each BLK elements is a trade-off problem with TBR. TBR > 1.05 Breeder Multiplier TBR Coolant Structural material Cooling Strength Surface heat load Nuclear heating Disruption (EM) Coolant pressure
3 Solid breeder / Water-cooled ~SlimCS~ The RAFM steel is themost likely option for the blanket structural material. Considering the corrosion of F82H K. Tobita, et al.: Nucl. Fusion 49 (2009) 075029
4 Solid breeder / Water-cooled ~SlimCS~ The blanket structure is modeled 1-D and the nuclear heating and the temperature inthe steady state are calculated by “ANIHEAT”. BLK coverage (~76%) SlimCS Net TBR>1.05 is difficult on high Pn An optimized arrangement of the each material thickness isdetermined to satisfy the operating temperature K. Tobita, et al.: Nucl. Fusion 49 (2009) 075029
5 LiPb / Water-cooled ~SlimCS~ • Assumption for use in DEMO reactor: Same conditions as SlimCS Water-cooled / Solid breeder BLK Cooling is only water (not “dual-coolant”) FW BW&Header Coolant LiPb Local TBR~1.2 (< Solid breeder) Plasma (neutron loading)
6 LiPb with Be pebble / Water-cooled ~SlimCS~ 1000℃ • Design condition • Assumption for use in DEMO reactor: • Coolant:Sub-super critical water, 23 MPa, Tin / Tout=290 / 360℃ • Multiplier:Be pebble (Temp. limit:600℃) LiPb 600℃ 550℃ Structural mat.:F82H (Temp. limit:550℃) Functional mat. (Temp. boundary):SiC/SiC Be pebble F82H 360℃ Coolant SiC/SiC Functional mat. (Temp. boundary) Structural mat. (Pres. boundary)
7 LiPb with Be pebble / Water-cooled ~SlimCS~ Double pipe structure: Boundary and cooling SiC/SiC Be pebble F82H 450mm Neutron wall load:Pn=5MW/m2 By using Be pebble, TBR is nearly equal to that of solid breeder on SlimCS. Issue (R&D): • Processing method of SiC/SiC
8 Problem of BLK analysis Blanket analysis method 1-Danalysis with simplified models is efficient in flexibly dealingwith a trial and error process in the design of blanket concept. ANIHEAT 1-D neutron transport (ANISN) 2-D + 1-D heat-transfer cal. 1-D “ANIHEAT” can not simulate a model accurately.
9 2D-analysis code ~DOHEAT~ ANIHEAT DOHEAT ANISN (1-D) DOT3.5 (2-D) Neutron transport Neutron flux + + APPLE (1-D) APPLE (2-D) Nuclear cal. Nuclear heating, TBR, etc + + Heat-transfer cal. Temperature 1-D 2-D
10 Analysis result sample by DOHEAT 2-D model Nuclear heating distribution Temperature distribution • DOHEAT will be useful for the next stepof BLK conceptual design
11 How much He-pumping power ? EU design Fusion power:2.385GW →Pumping power:194MW Dual-coolant Case of single-coolant (He), how much is pumping power, GW class ?? Question If we cool an uniform heating element equivalent to thermal power 2.4GW by some He-cooling pipe, How much is total pumping power for pressure loss? an uniform heating element equivalent to thermal power 2.4GW… ○Assumption 50W/cc He: Tin/Tout=300/380℃ p=8MPa d0 Tin, v, p ○Approximation for pumping power Ratio of specific heat L Tout, v’, p-Dp Volume flow Specific heat Compressor efficiency(=0.85)
12 Evaluation result of He-pumping power (1) Because the removal heat is small Tin/Tout=300/380℃, p=8MPa, d0=8mm per 1 cooling channel Because the pressure loss is large per 1 cooling channel Net electric output Fusion power:2.4GW Electric power:0.88GW (efficiency: 0.37)
13 Evaluation result of He-pumping power (2) Tin/Tout=300/380℃, p=8MPa Heat removal:medium Pressure loss:small Packing factor:large Heat removal:large Pressure loss:large Packing factor:large Packing factor (TBR) Occupancy limit by pipe (>75%) Heat removal:medium Pressure loss:large Packing factor:small Heat removal:small Pressure loss:small Packing factor:large
14 Summary • The water-cooled LiPb+Be BLK has a potential for DEMO reactor But, it also has some R&Ds (SiC/SiC etc…) • We deloped the “2-D nuclear thermal analysis code” DOHEAT DOHEAT will be useful for not only LiPb BLK but also “all” BLK analysis • The He-cooling system requires large pumping power. The key is heat removal vs. TBR Future Plan • Consideration of the effectiveness of LiPb flow (convection, MHD, etc) • Detailed design for He-cooled BLK system