Damage Calculations for Devices in the Diagnostic Penetrations of a Fusion Reactor

Degradation of neutron-sensitive devices for fusion diagnostics is calculated as a function of location in ducts through bulk shields. It is shown that single-crystal semiconductor devices, such as n/p silicon diodes, will undergo severe degradation even at the rear of the shield. It will be necessary to replace devices at frequent intervals or withdraw semiconductor parts after a measurement. Device life can be extended by distance, elbows, shortening of exposure. hardening, or a combination thereof.