J. Samuel Walker calls the 1979 Three Mile Island crisis a local event that gained worldwide attention and forever changed the nuclear energy industry.

Walker, an American historian and nuclear energy expert, will speak on the Three Mile Island partial meltdown from 7 to 9 p.m.Tuesday, March 25, at York College's DeMeester Recital Hall.

The free event commemorates the 35th anniversary of the Three Mile Island crisis, the worst nuclear accident in U.S. history.

TMI interest: Walker, of University Park, Md., said he plans to give an informal talk and answer questions about the TMI incident that still generates interest among the general public and nuclear energy professionals and experts.

"It was such a big event in York, Lancaster and Dauphin (counties) and throughout the country and the world, and it was a traumatic event for a lot of people who lived in the area," Walker said. "It opened people's eyes about the things that had to be changed. There were regulatory changes, control room and instrumental panel changes, a lot more emphasis placed on training operators on how to respond to all kinds of situations."

Meltdown: Friday, March 28, will mark the 35th year after the severe core meltdown at Three Mile Island's Unit 2 reactor, which is on an island in the Susquehanna River off the shoreline of Goldsboro.

About 144,000 residents of York, Dauphin and Lancaster counties evacuated their homes when Pennsylvania Gov. Richard Thornburgh urged women and young children within a five-mile radius of TMI to leave. Federal officials lifted the evacuation advisory on April 9, 1979, but by then many residents had already returned home. The accident did not lead to any injuries or deaths, according to the U.S. Nuclear Regulatory Commission.

About Walker: Walker wrote a book about the incident titled "Three Mile Island: A Nuclear Crisis in Historical Perspective" in 2004. He has written several other books, including "The Road to Yucca Mountain: The Development of Radioactive Waste Policy in the United States" in 2009.

In 1997, Walker wrote "Prompt and Utter Destruction: Truman and the Use of Atomic Bombs Against Japan," which won the Organization of American Historians Richard W. Leopold Prize for historical work done by historians outside institutions of learning.

He worked as Nuclear Regulatory Commission historian from June 1979 until his retirement in 2010.

Walker's talk will give the public a chance to hear an "expert and objective point of view" about the TMI incident and to learn what role nuclear energy plays in the global climate debate today, said Peter Levy, professor of history at York College.

"Walker knows the advantages and disadvantages of nuclear energy," he said. "He knows the inside of the history of the regulation of nuclear energy in this country."

The event is part of York College's Sustainability and Environmental Studies' cultural events series and is co-sponsored by the History and Political Science department.

—Reach Eyana Adah McMillan at emcmillan@yorkdispatch.com.