Depending on the plant, they will typically put out a "lay off request". Those wanting to be on the first lay off will 'sign up'. This will include Sr. Techs, Jr. Techs, and Decon. If people have another plant to go to, the current plant will get them out first. Then, there is typically a 'second lay off'... if you don't want a lay off until the very end of the outage, don't sign up for any of the lay offs. However, there have been people laid off that didn't request it, for various reasons.
Just do the BEST job you possibly can and try not to complain. This tells management that you are worthy of staying till the very end.
GOOD LUCK!!