short for Temporary Disadvantage, Shutdown a variant on Temporary Disadvantage which causes a triggered disadvantage such as Electrical to deactivate an advantage rather than a character.
Explained in Power-Ups 8 p 18.
This was originally hinted at in GURPS Powers 106 when discussing Always On abilities
This also introduces the 2.5 x price = N/A for mental disadvantages with Self-Control Numbers