TOKYO — Prime Minister Naoto Kan said Tuesday that Japan would abandon plans to build more nuclear reactors, saying his country needed to “start from scratch” in creating a new energy policy.

Mr. Kan’s announcement came as Japan allowed residents of evacuated areas around the stricken Fukushima Daiichi nuclear plant to briefly revisit their homes for the first time since the devastating earthquake and tsunami in March caused the nuclear accident at the plant.

Tuesday’s decision will mean the abandonment of a plan that the Kan government released last year to build 14 nuclear reactors by 2030 and increase the share of nuclear power in Japan’s electricity supply to 50 percent. Japan currently has 54 reactors that before the earthquake produced 30 percent of its electricity.

The cancellation of the planned nuclear plants is the second time that Mr. Kan has suddenly announced big changes in Japanese nuclear policy without the usual endless committee meetings and media leaks that characterize the country’s consensus-driven decision-making process. Mr. Kan appears to be seeking a stronger leadership role after criticism of his government’s sometimes slow and indecisive handling of the Fukushima accident.