Essay Example on The main components of fusion reactors are Blanket

The plasma is confined and shaped by a combination of magnetic fields from three main origins toroidal field coils poloidal field coils and plasma currents The nested magnetic surfaces can confine shape and control the plasma pressure equivalent to a few atmospheres with a density 106 times smaller than in the atmosphere n 1020 m3 T 10 keV Aiming in ITER at steady state operation all the coils are superconducting ITER uses high performance internally cooled superconductors called cable in conduit conductors in which bundled superconducting strands mixed with copper are cabled together and contained in a structural steel jacket The niobium tin Nb3Sn superconducting strands used in ITER s toroidal field and central solenoid while niobium titanium NbTi in poloidal field coil 6 Vacuum Vessels The whole fusion experiments are carried out in vacuum vessels an airtight steel chamber which also acts as a first safety containment barrier It is a component with a multiple function It provides remote handling operations for diagnostics heating systems water circulation for cooling And improves neutrons shielding with improving plasma stability It is entirely enclosed by large vacuum chamber cryostat The ITER vacuum vessel will measure 19 4 metres across outer diameter 11 4 metres high and weigh approximately 5 200 tonnes with the installation of the blanket and the divertor the vacuum vessel will weigh 8 500 tonnes 6 10 Divertor Diverter is the bottom of the vacuum vessel it extracts heat and ash produced minimizes plasma contamination and protects surrounding walls from thermal and neutronic loads Each diverters cassette assemblies has a supporting structure in stainless steel and three direct plasma facing components the inner outer vertical targets and the dome 

The production of one tritium atom by the 6Li n α consumes one neutron while its fusion with a deuterium generates only one neutron which exhibits a significant probability 30 35 of not being available for tritium production because of parasitic absorptions in blanket structures or streaming through the blanket openings These neutron losses must therefore be compensated for usually by also incorporating in the blanket in addition to a 6Li rich compound a material should be multiplying neutrons by n 2n reactions like Be Beryllium or Pb Lead 11 The major candidate breeding materials consist of liquid breeders mainly liquid metals although recently some attention has been given to FLiBe and lithium ceramic breeders 12 A variety of breeding blanket concepts has been considered ranging from more conservative concepts to higher risk higher payoff concepts for future reactors In general there are three types Ceramic breeder blanket Self cooled liquid metal blanket and liquid metal with helium cooling blanket