Such sentiments have led to a very public loss of hope by the 11,350 displaced residents of Okuma, one of nine communities within 12 miles of the stricken plant that were evacuated.

After living in school gymnasiums and other shelters for about a month, Okuma’s town hall officials and about 4,300 of its residents relocated to temporary sites in Aizu-Wakamatsu, with most of the rest scattered as far as Tokyo, about 140 miles away. The mayor, Toshitsuna Watanabe, immediately began drawing up plans for returning to Okuma that called for a group to resettle a small corner of the town where radiation levels were relatively low. The settlers would then slowly expand the livable areas, decontaminating one street or building at a time, like colonists reclaiming a post-apocalyptic wilderness.

Last fall, the plan won de facto approval when Okuma residents re-elected Mr. Watanabe over a challenger who had called for building a new town at a safer location. Hopes were still high early this year when the Environmental Ministry began a decontamination program, with a budget of $4.8 billion for 2012 alone, that employed a small army of workers to scrape away top soil, denude trees and scrub down buildings in Okuma and other evacuated communities.

But the ministry said this summer that an experimental effort to decontaminate a 42-acre area in Okuma had failed to reduce radiation dosages by as much as had been hoped, leading officials to declare most of the town uninhabitable for at least another five years. That forced Okuma’s officials to change the target date of their “road map” for repopulating the town to 2022, instead of 2014.

“People are giving up because we have been hit by negative news after negative news,” said Mr. Watanabe, 65, who set up a temporary town hall in a former girls’ high school on a corner of Aizu-Wakamatsu’s six-century-old castle. “Keeping our road map is the only way to hold onto hope, and prevent the town from disappearing.”

Image Okuma’s town hall officials and about 4,300 of its residents relocated to temporary sites in Aizu-Wakamatsu. Credit... The New York Times

Mr. Watanabe admits that his plan has a dwindling number of adherents. In response to a questionnaire sent to Okuma’s evacuees by the town hall in September, only 11 percent of the 3,424 households that responded said they wanted to go back, while 45.6 percent said they had no intention of ever returning, mostly because of radiation fears.