Sims disappearing upon arriving to university

jbp496029​  This is a relatively common issue with traveling.  The EA version of the travel transition is somewhat unreliable and prone to breaking.  I can try to help you get through it, but it's possible that you'll run into the same issue on the way back.

So if you're willing, I'd instead suggest that you add NRaas Traveler, which replaces the travel transition with one that's much more stable, along with ErrorTrap, Overwatch, and Register.  You can find more information about them here:

Sims 3 - Common Game Fixing Mods - Hero Approved | EA Forums - 8291748

If you don't want to add mods, and you want to try to travel anyway, let me know, and I'll write out what to do.  In that case, make a backup of the pre-travel save now, so you have it if you need it later.