When a nuclear reactor wall is irradiated many vacancies and interstitials are created?

Leesville

When a nuclear reactor railing is irradiated, myriad vacancies and interstitials are created. The vacanciescluster compile to sort voids; what do you think happens to the interstitials?



Carthage

The interstitial metallic atoms dislodged from their organized lattice structure become positioned such that they can and do interfere with any stress relieving lattice corrections such as would occur in high pressure systems such as reactor plants. The reactor wall is under tremendous stress from actual internal pressure as well as stresses due to temperature differentials across the wall thickness. The interstitial obstacles simply make the metal rigid and, thus, brittle or more subject to brittle fracture. The problem can be relieved somewhat by annealing (raising the embrittled metal to a high temperature for a while, allowing the lattice structure to heal or reform). Conversely, at lower temperatures the pressure vessel is far more susceptible to brittle fracture, especially with voids or cracks and any such stress raiser.



Morley

Neutron embrittlement is a common problem in very very very old reactors. When the wall is irradiated it means the coolant isn't efficiently capturing the neutrons. It also means that the wall is designed of the wrong material. Zirconium nitride is great stuff for coating walls, etc... you tell me why.