Dartmouth President John Kemeny was chosen to lead the commission, which eventually established that the plant had suffered a loss of coolant. A faulty valve and a failure of the operators to correctly diagnose the problem in the initial stages of the accident also contributed to the severity of the event.
John Kemeny's papers contain many items related to his work on the commission, including several drafts of his acceptance. One starts:
Mr. President:The Thayer School of Engineering and the Dickey Center are sponsoring a symposium on nuclear energy with a focus on the 35th anniversary of the Three Mile Island event this Friday, March 28. The event is free and open to the public.
This is an awesome responsibility! I have tried to think of every reason why I should not accept. But when the President of the United States asks... the only possible answers is "yes".
John Kenemy's papers are available by asking for MS-988. A guide to the collection is available.