At one time there were no less than five nuclear reactors operating in the state of Massachusetts. This may come as a surprise to some since the state had only one commercial nuclear power plant, Pilgrim Nuclear Power Station Unit 1.
The other reactors were the research reactors located at UMass Lowell, MIT in Cambridge and at Worcester Polytechnic Institute.
The fifth reactor was a bit of a secret. It was part of the Army Materials Lab at the Watertown Arsenal.
If you hold your pointer over the word "Reactors" on the left you'll see links to each of those reactors plus for reactors in nearby states.
The connection between nuclear power and the Cold War is clear and there is evidence that the three university reactors in the state were involved in research to support the Cold War effort.