What is the name of the process in which the fuel is removed from a nuclear plant, its surfaces are cleaned, and people are permanently prevented from coming in contact with the building?

Decommissioning

I found this answer on a quizlet, which I will link for you to reference-

https://quizlet.com/469164011/ecology-and-environmental-science-ch-9-flash-cards/?i=13ii26&x=1jqY

Hope this helps :)