Radiation

The most common long-term effect of radiation on materials is it makes them brittle.  Polymers and other “soft parts” can fail prematurely and even metal components may fail when subjected to stress.  The length of time required for most metal parts to fail is quite long, especially for tougher more ductile materials like stainless steels.  Certain materials such as Viton do not perform well at all when exposed to radiation.

One of the first steps necessary to qualify equipment subject to radiation is to analyze all of the components and determine which of those will fail prematurely given the type and level of radiation to which the component will be subjected.  It is then often necessary to change certain materials, such as Viton O-rings to Buna-N.

Unlike thermal aging, in which we must test components at higher temperatures to shorten the testing time, the effects of radiation are fairly linear, so 100 Rad of exposure causes about the same amount of damage regardless of whether the exposure time is a day or twenty years (this is not true for living organisms).