Peculiarities of using of cryogenic pumps under irradiation effect

Carried out are calculations and evaluations of operation specificity effect of cryogenic pumps under hot conditions, analogous to the conditions of thermonuclear reactors with the purpose of obtaining recomendations and forecast, as well as admissible conditions of their application. With account of specificity of fusion reactor and admittances relatively to plasma temperature in (Tsub(e,i)<=1 keV) pumping out range considered are physical processes, passing in the vacuum system and cooling system under the effect of factors characteristic of common vacuum systems, as well as under the effect of confined plasma. Pumping out of He3 will produce the main difficulty when using cryogenic pumps in thermonuclear devices. It is shown, that the total effect of all the factors influencing cryopumps causes specific heat conductors at the 10-3 W/cm2 level, desorption fluxes about 1O13 cm-2xs-1 and approximately 10% decrease of adherence coefficients. The value of the energy rate factor will constitute 10-2 W/lxs, which as before, leaves cryopumps in the range of the most effective pumping out means