AbstractOne criterion for the choice of first wall materials in the post-activation behavior after exposure to fast fusion neutrons. For the reference material, stainless steel SS316, finite-element model calculations under NET technology phase conditions revealed the heat output after thermonuclear operation to stay almost constant for more than one year, declining with the decay of Mn and Co isotopes. Water cooling of the irradiated first wall was extended tto five hours after plasma shutdown. As soon as the water cooling is terminated, the temperature of the steel rises to >800°C, unless the top/bottom surfaces will be cooled. If a forced gas convection is installed after shutdown of watercooling, the temperature of the first wall may result in a steady state of as low as 200°C, depending on the velocity of the gas flow. If lower temperatures are desired for maintenance purposes, additional operational cooling will have to be considered.
Afterheat transient in ITER after a total loss of coolant accident