SOMA, Japan — The catastrophe at Japan’s stricken nuclear complex is now worse than Three Mile Island, experts said Tuesday, after the crisis escalated again with a new explosion — this one opening holes in the structure housing a pool with radioactive rods of spent nuclear fuel — and fears that the vessel containing one reactor had been compromised.

An explosion on Monday at Unit 2 within the Fukushima Dai-ichi nuclear plant “may have affected the integrity of its primary containment vessel,” the International Atomic Energy Agency said Tuesday. That means radioactivity could be leaking from the containment vessel.

Moreover, an explosion overnight at Unit 4 opened two large holes in the structure housing rods that had been used to make nuclear fuel.

Japanese officials told the IAEA that the spent fuel storage area had caught fire and that radioactivity was “being released directly into the atmosphere.”

After the fire was extinguished, a Japanese official said the pool might still be boiling, though the reported levels of radiation had dropped dramatically by evening.

Japanese Prime Minister Naoto Kan said low levels of radiation had spread from the complex along Japan’s northeastern coast.

The radiation releases prompted Japan to order 140,000 people to seal themselves indoors and a 30-kilometer (18-mile) no-fly zone was imposed around the Fukushima site Tuesday.

About the only good news Tuesday was the fact that the winds are blowing most of the radioactivity out to sea.

Soon after the latest events, France’s nuclear safety authority ASN said the disaster ranks as a level six on the international scale of one to seven.

Level seven was used only once, for Chernobyl in Ukraine in 1986. The 1979 accident at the Three Mile Island nuclear power plant in Pennsylvania was rated a level five.

“It is very clear that we are at a level six,” ASN President Andre-Claude Lacoste told a news conference in Paris. “We are clearly in a catastrophe.”

On Three Mile Island, the radiation leak was held inside the containment shell — thick concrete armor around the reactor. The Chernobyl reactor had no shell and was also operational when the disaster struck. The Japanese reactors automatically shut down when the quake hit.

The IAEA said about 150 people had received monitoring for radiation levels and that measures to “decontaminate” 23 of them had been taken.

Clearing up nuclear questions

Though Japanese officials urged calm, Tuesday’s developments fueled a growing panic in Japan and around the world amid widespread uncertainty over what would happen next.

In the worst-case scenario, the reactor’s core would completely melt down, a disaster that would spew large amounts of radioactivity into the atmosphere.

Officials in Tokyo — 150 miles to the south of the plant — said radiation in the capital was 10 times normal by evening but there was no threat to human health.

Closer to the stricken nuclear complex, the streets in the coastal city of Soma were empty as the few residents who remained there heeded the government’s warning to stay indoors.

Officials just south of Fukushima reported up to 100 times the normal levels of radiation Tuesday morning, Kyodo News agency reported. While those figures are worrying if there is prolonged exposure, they are far from fatal.

‘Please do not go outside’
Officials warned there is danger of more leaks and told people living within 19 miles of the Fukushima Dai-ichi complex to stay indoors to avoid exposure that could make people sick.

“Please do not go outside. Please stay indoors. Please close windows and make your homes airtight,” Chief Cabinet Secretary Yukio Edano told residents in the danger zone.

“These are figures that potentially affect health. There is no mistake about that,” he said.

Some 70,000 people had already been evacuated from a 12-mile radius from the Dai-ichi complex. About 140,000 remain in the new warning zone.

Friday’s 9.0-magnitude earthquake and the ensuing tsunami have killed more than 10,000 people.

Desperate efforts
Workers were desperately trying to stabilize the three reactors at Units 1, 2 and 3. Releases of hydrogen gas caused explosions that destroyed the outer structures at each unit. Unit 4, where the pool is, had been under maintenance and was not operating at the time of the quake and tsunami.

Since the quake, engineers have been injecting seawater into the reactors as a last-ditch coolant. Tokyo Electric Power Co., which operates the plant, said it might use helicopters to inject seawater inside the pool area within three days.

Officials said 50 workers were still at the Fukushima site. About 800 other staff were evacuated. The fires and explosions at the reactors have injured 15 workers and military personnel.

The death toll from last week’s earthquake and tsunami jumped as police confirmed the number killed had topped 2,400. Officials say that at least 10,000 people may have died in Miyagi province alone, but those deaths are not confirmed.

Hajime Sato, a government official in Iwate prefecture, one of the hardest-hit, said deliveries of supplies were only 10 percent of what is needed. Body bags and coffins were running so short that the government may turn to foreign funeral homes for help, he said.

Rescuers also found a 70-year-old woman alive four days after the disaster .

Osaka fire department spokesman Yuko Kotani said the woman was found inside her house that was washed away by the tsunami in northeastern Japan’s Iwate prefecture.

Another survivor, described as being in his 20s, was shown on television being pulled from a building further down the coast in the city of Ishimaki after rescue workers heard him calling for help.

The impact of the earthquake and tsunami dragged down stock markets. The benchmark Nikkei 225 stock average plunged for a second day Tuesday , nose-diving more than 10 percent to close at 8,605.15 while the broader Topix lost more than 8 percent.

To lessen the damage, Japan’s central bank made two cash injections totaling $98 billion Tuesday into the money markets after pumping in $184 billion on Monday.

Initial estimates put repair costs in the tens of billions of dollars , costs that would likely add to a massive public debt that, at 200 percent of gross domestic product, is the biggest among industrialized nations.

Source: MSNBC