Edwin E. Kintner, 90, who played a role in early efforts to harness nuclear power and later witnessed its destructive potential while heading the decontamination of the Three Mile Island nuclear power plant after a partial meltdown, died May 7 in Exeter, N.H.

Mr. Kintner had prostate cancer, his son Eric said.

After World War II, Mr. Kintner helped develop a reactor for the Navy that was later used in the first nuclear-powered submarine, the Nautilus.

He went on to a wide-ranging career in military and civilian energy. He worked for the Atomic Energy Commission and was head of the Department of Energy's fusion program, overseeing the construction of reactors and developing nuclear power as an alternate source of energy.

When the core of the reactor melted down at the Three Mile Island plant near Harrisburg in March 1979, an event that severely set back the development of nuclear power plants, he was named to oversee the cleanup.

Mr. Kintner was born in Paris, Ohio, on May 1, 1920. He graduated from the Naval Academy in 1941 and later earned master's degrees in naval construction, ocean engineering, and physics at the Massachusetts Institute of Technology.

In 1949, he was selected to work on the Nautilus, a secret project. He helped build sister vessels for the Navy until he retired in the early 1960s at the rank of captain.

In 1983, he became executive vice president of General Public Utilities Nuclear Corp., the owner of TMI, in charge of finishing the cleanup of its reactor.

In the accident's wake, Mr. Kintner worked to standardize nuclear training and operation and, in 1990, he was inducted into the National Academy of Engineering. - N.Y. Times News Service