Kan Warns of High Radiation Level

TOKYO—Japanese Prime Minister Naoto Kan said Tuesday that there is a high risk of elevated levels of radiation from a reactor at the Fukushima nuclear power plant where an explosion occurred earlier in the day, and urged people within 30 kilometers of the plant to stay indoors.

“Substantial amounts of radiation are leaking in the area,” Mr. Kan said on television at 11 a.m. in Tokyo. “We are making utmost efforts to prevent further explosions or the release of radioactive materials,” he said.

Early Tuesday morning local time, authorities said that an explosion inside part of the No. 2 reactor at the Fukushima Daiichi nuclear power plant appeared to have caused damage to the unit, and some staff were evacuated from the facility as radiation levels at the site rose sharply.

Mr. Kan began his address by asking people to be calm about the situation. He said that the government is doing everything it can to prevent further radiation leaks.

The Daiichi plant, located 160 miles northeast of Tokyo, was brought down by Friday’s massive earthquake, which automatically shuts off the power generation by the reactors, while the tsunami damaged the generators designed to supply backup power.

The utility has been struggling since then to safely shut down the reactor cores at the three operating reactors at the facility.

Experts say the key to preventing the current crisis from turning into a full-blown disaster is to protect the reactor’s containment structure, so that radiation is kept inside even after significant nuclear fission due to damage to the fuels. In the 1979 Three Mile Island incident in Pennsylvania, the containment structure remained intact, minimizing health effects on local residents.

Write to William Sposato at william.sposato@dowjones.com

Agence France-Presse/Getty ImagesJapanese sailors rescue Hiromitsu Shinkawa Sunday, two days after the 60-year-old was washed to sea on the roof of his Minamisoma home by a tsunami caused by a powerful earthquake. Thousands are feared dead.

Japan’s quake-ravaged northern communities continued to be pinched by food and water shortages Monday, while even cities far from the damage experienced “aftershocks” as the effects from Friday’s disaster rippled through the economy and markets.

Rescue workers struggled to bring supplies to thousands of residents of towns along the northeast coast, hardest hit by the 8.9-magnitude quake and tsunami on Friday. Survivors appeared on television, saying they didn’t have power and were running out of food and water. People atop one building had written a huge Chinese character for “water” on the roof, so it could be seen by rescue helicopters.

Residents are dealing with a lack of rations in Northern Japan, as transportation equipment is hampered in the aftermath of Friday’s quake. WSJ’s Eric Bellman reports from Sendai.

The official death toll continued to climb, reaching around 1,800 by Monday afternoon. National broadcaster NHK reported that more than 450,000 people had moved to temporary shelters in the affected areas. (more…)