Passive safety considerations in thermal design of fusion blankets

The potential for passive heat removal from the fusion reactor first wall and blanket is investigated in various designs. The impact of boron carbide on decay heat in the shield type of blankets that may be used in the early experimental reactors is assessed. The effect of blanket design conditions on the temperature rise following coolant transients in tritium breeding blankets in power reactors is discussed. It is shown that passive plant protection requirements will impose limits on the neutron wall loadings in D-T power reactors with reduced activation metallic structures in the range of 3-8 MW/m2. Such limits are below those required to ensure public safety following undercooling events by passive dissipation of decay heat. (orig.)