xrays are a light fequency, what messes up your hard drive when you format it for example, is a strong magnet, which is a magnetic field, not light wavelngths. It gets bombarded with xrays anyway and seems pretty fine so i would say it would be ok.
Also, think about all of the laptops that people take with them and they get put in the box and put through the x-ray, i know i have seen them being put through, and they work fine still.
Google it just to be sure, see if anyone else somewhere else knowsw
If you put them in a bag then there is a chance that they could get crushed or something i suppose but i doubt it would do too bad damage. I have tried breaking a HDD before (old one that didn't work so was binning, better to be safe than sorry as it had personal details, bank information, adress etc) and it is damn hard, had to use screwdrivers and chissles and hammers and everything.
I would say if you want to be totally safe put em all in a bag with bubblewrap in or something, or if they let you, just take them on a plane with you, that is if you aren't shipping them. If you are shipping them, a cradboard box with all gaps/creases (and i mean every crease and crevice) taped up with parcel tape and stick bubble wrap between each layer, should be absolutely fine
