Kazuyoshi Nakamura, 84, recalls how difficult life was as a child in Kataku, a tiny fishing hamlet within Kashima that faces the rough Sea of Japan. His father used a tiny wooden skiff to catch squid and bream, which his mother carried on her back to market, walking narrow mountain paths in straw sandals.

Still, at first local fishermen adamantly refused to give up rights to the seaweed and fishing grounds near the plant, said Mr. Nakamura, who was a leader of Kataku’s fishing cooperative at the time. They eventually accepted compensation payments that have totaled up to $600,000 for each fisherman.

“In the end, we gave in for money,” Mr. Nakamura said.

Today, the dirt-floor huts of Mr. Nakamura’s childhood have been replaced by oversize homes with driveways, and a tunnel has made central Kashima a five-minute drive away. But the new wealth has changed this hamlet of almost 300 in unforeseen ways. Only about 30 aging residents still make a living from fishing. Many of the rest now commute to the plant, where they work as security guards or cleaners.

“There was no need to work anymore because the money just flowed so easily,” said a former town assemblyman who twice ran unsuccessfully for mayor on an antinuclear platform.

A Flow of Cash

Much of this flow of cash was the product of the Three Power Source Development Laws, a sophisticated system of government subsidies created in 1974 by Kakuei Tanaka, the powerful prime minister who shaped Japan’s nuclear power landscape and used big public works projects to build postwar Japan’s most formidable political machine.

The law required all Japanese power consumers to pay, as part of their utility bills, a tax that was funneled to communities with nuclear plants. Officials at the Ministry of Economy, Trade and Industry, which regulates the nuclear industry, and oversees the subsidies, refused to specify how much communities have come to rely on those subsidies.

“This is money to promote the locality’s acceptance of a nuclear plant,” said Tatsumi Nakano of the ministry’s Agency for Natural Resources and Energy. A spokesman for Tohoku Electric Power Company, which operates a plant in Higashidori, said that the company is not involved in the subsidies, and that since Fukushima, it has focused on reassuring the public of the safety of nuclear plants.