UPDATE: Fears of a nuclear meltdown have risen again in Japan, as the Fukushima Daiichi plant showed dangerously low water levels, exposing its uranium fuels rods and increasing the threat of radiation reaching the nearby public. At least 190 people have been exposed to radiation near Fukushima, officials say—as well as 17 U.S. navy personnel who were sent in to aid relief efforts. 185,000 people from the area have been evacuated. And it’s not just one plant: A Japanese official said that there are meltdown fears at three of the nation’s nuclear facilities.

The Daily Beast's Lennox Samuels reports on Japan's fears of a meltdown. Plus, shocking photos and videos of the quake and tsunami, the most gripping survivor stories, and a nuclear expert talks worst-case scenarios.

Shocking Photos: Japan Devastation and Aftermath

Japan’s struggle to cope with a catastrophe that has seen the country hit by a huge earthquake, epic tsunami, and partial nuclear meltdown sustained another blow Monday morning as a second explosion rocked the nuclear plant damaged in the initial disaster. As fresh plumes of smoke billowed over the Fukushima Daiichi plant, authorities reported that up to six people were injured and seven were missing after the blast.

And the latest explosion came with additional bad news. About 2,000 more bodies were found on a peninsula in Miyagi Prefecture, the state hit hardest by the twin disaster. That discovery follows Sunday’s decision by officials to raise the projected death toll above 10,000, based on reports that more than half the population of a single town along the northeastern coast has not been accounted for. News agencies were reporting that the number of fatalities could eventually number in the tens of thousands, as rescue and recovery teams pushed farther toward more isolated communities. Almost 200,000 people have fled the northeast so far.

The government said there was little chance of radiation exposure from the explosion at the Unit 3 nuclear reactor, but warned the remaining citizens in the area to stay indoors. Officials said the reactor remained intact and that workers were continuing to pump in seawater to try to keep it cool. “There is no possibility that a massive amount of radiation has been leaked,” said Chief Cabinet Secretary Yukio Edano. But he added that, as with the explosion of the nearby Unit 1 on Sunday, “We can see a higher level of radiation.”

The blast was not unexpected. On Sunday, Edano told reporters that hydrogen buildup at Unit 3 could result in an explosion similar to the one at Unit 1. Authorities had worked frantically to head off another blast, fearing that such an event would leave them battling partial meltdowns in two reactors in an area already devastated by the massive earthquake and ensuing tsunami.

Prime Minister Naoto Kan announced that the government had asked Tokyo Electricity Power Company to rotate blackouts throughout the country to conserve the power supply, which he said had been severely reduced by the pre-emptive shutdown of nuclear plants in the northeast, as well as some other power plants. “We do not have any prospect of restoring the electricity in the next few days,” he said. He warned that the blackouts would adversely affect water, gas and medical facilities, as well as industry—an indication that the government expects the ongoing crisis to batter the nation’s already reeling economy. “This is the biggest hardship we have experienced since World War II,” he declared.

The prime minister, looking fatigued, told a press conference that 50,000 of an anticipated total of 100,000 military personnel had been deployed to help with rescue, recovery and humanitarian efforts, along with 2,500 police officers. He added that 12,000 people have been rescued so far. “To the people of Japan, I’d like to ask you for your understanding,” he said.

Prior to the latest explosion, Edano told the media that some fuel rods in Unit 3 were briefly exposed, raising temperatures and pushing radiation levels above the legal limit, which he acknowledged raised the “possibility” of another explosion.

“A part of the core to a certain degree within the reactor is deforming,” he said at a press briefing, but he added that the rods were not exposed long enough for the incident to be called a meltdown. And he said radiation released into the air was not sufficient to be harmful to people, comparing it to the effect having a stomach X-ray would have on a person.

Unit 3 now joins Unit 1 as the reactors—there are six in all—that could experience meltdowns if authorities are not able to cool them down. Friday’s 8.9-magnitude earthquake knocked out power at the plant and the area around it, and the tsunami disabled the backup generators that kick in during such emergencies. A water shortage, also caused by the natural disasters, has forced officials to flood the reactors with seawater to cool them. If the fuel rods overheat to a sufficiently high temperature, they would burn through the reactor walls, melting them down.

“If the containment vessel is breached that’s the nightmare scenario,” Pakistani nuclear physicist Dr. Pervez Hoodbhoy told The Daily Beast. “I’m very worried. This is what people used to talk about when they discussed how dangerous nuclear power was. Always there would be reassurance from the other side: ‘Don’t worry. We have everything under control, we have multiple fail-safe systems.’ I hope they are right.”

Edano said nine people who had been exposed to radiation released when authorities bled vapor from Unit 1 to relieve pressure were found to have radioactive particles only on their clothes and skin. “If contamination only stays on clothes and the surface of skin” it does not present a hazard, he said.

But many thousands of residents continued to stream from the stricken northeast—to escape the possibility of contamination, but also in search of food, water and shelter. In addition to the thousands evacuated because they live within about 12 miles of the plant—considered a danger zone—many took to damaged roads in their vehicles. At least 50,000 people live within six miles of the Fukushima plants.

Throngs of residents queued for food at shops, but in most cases, the shelves had been stripped bare, sometimes by people who apparently were buying out of panic. And given poor road conditions, delivery of foodstuff and liquids was spotty in a number of smaller communities in the prefectures, or states—Miyagi, Iwate, and Aomori—that bore the brunt of the disaster’s destruction. Kan said the government was considering airlifts and food drops by sea because of the bad roads.

Such food drops cannot come soon enough for those remaining in the area. Many smaller towns and villages have not yet been reached by authorities, who often find more bodies when they do arrive on the scene. Minamisanriku, a town of 17,300 located a mere half-mile or so from the sea in Miyagi Prefecture, was one of those. Video images of what was once a quaint and thriving port town showed—instead of houses—mounds of splintered lumber strewn around, along with cars and trucks hurled about willy-nilly. And an estimated 10,000 of its residents were missing and feared dead. Video also showed physics-defying scenes in Sendai, the hardest-hit city, where large boats teetered atop two-story buildings, flung there by the advancing waves. Some 7,500 of the Minamisanriku survivors are now being housed in shelters.

Aftershocks continue to rattle Sendai and its environs, including a 6.9-magnitude temblor on Sunday. Many phone lines are still down in the port, the closest city to the epicenter of the quake, which struck at 2:46 p.m. Japan time Friday some 80 miles off the coast—crashing two tectonic plates against each other, heaving the seabed upward, and unleashing waves of up to 30 feet onto the shore. Tokyo also is being hit by intermittent tremors—and “quake alerts are going off like crazy,” according to Takashi Yokota, editor of Newsweek Japan.

More than 70 countries are sending or have sent aid to the besieged country, including the U.S., which is ferrying in supplies and medicine from its military base in Okinawa Prefecture, and Britain, which has dispatched a 63-person team with rescue equipment. American and British rescue teams were on the ground and heading toward the northeast. Others sending assistance include Germany—which itself has 17 nuclear plants—Taiwan, Spain, South Korea, and Russia.

With Mike Giglio in New York and Takashi Yokota in Tokyo

Lennox Samuels is a Newsweek/Daily Beast editor based in Bangkok. He covered the 2004 Indian Ocean tsunami.