From the UW archives, check out this film of the Nuclear Reactor Building from 1963, two years after the building was completed:

For more information on this clip, see the article published in UW Today back in 2012: Lost and Found Films: The UW Nuclear Reactor, 1963

This film was also featured in the video the Washington Trust for Historic Preservation created about the Nuclear Reactor Building for the 2015 Most Endangered List which you can find here.