They are calling them the "Fukushima 50" - 50 dedicated and brave technicians and engineers who appear to be all that is standing between the people of Japan and an unprecedented nuclear catastrophe.

Earlier in the day Japanese time, most of the workers were evacuated for a couple of hours but the latest word is that they are planning to send them back in. Tokyo Electric and Power is saying it hopes to double the number of workers to 100.

The workers' families  live just a few miles from the plant so there is an extra urgency to their work. No one has yet assessed their total exposure to radiation but even with protective gear, there is concern that their health will be affected.

Meanwhile, the situation at all 5 reactors has not been stabilized and at a couple of sites, the news has gotten worse. There has been another fire to contend with, and it appears that one of the reactor vessels may have been breached. The New York Times:

Japan's nuclear crisis intensified dramatically on Wednesday after the authorities announced that a second reactor unit at the stricken Fukushima Daiichi plant in northeastern Japan may have ruptured and appeared to be releasing radioactive steam.

The break, at the No. 3 reactor unit, worsened the already perilous conditions at the plant, a day after officials said the containment vessel in the No. 2 reactor had also cracked.

Such were the radiation levels above the plant, moreover, that the Japanese military put off a highly unusual plan to dump water from helicopters - a tactic normally used to combat forest fires - to lower temperatures in a pool containing spent fuel rods that was overheating dangerously.

However, in one of a series of rapid and at times confusing pronouncements on the crisis, the authorities insisted that damage to the containment vessel at the No. 3 reactor - the main focus of concern on Wednesday - was unlikely to be severe.

Yukio Edano, the chief cabinet secretary, was quoted by Kyodo news agency as saying the possibility that the No. 3 reactor had " suffered severe damage to its containment vessel is low." Earlier, he had said the vessel may have been damaged.

You can see why many believe there is an on-going coverup by the company with the assistance of the government. But all is not as it appears. The simple truth is, sensors that would tell operators what's going on in the reactor are damaged or destroyed so that it is very difficult to assess what condition they are in. Nobody can get close enough to measure radiation levels accurately. Remote sensing devices might be giving false measurements. And since the cameras in the core aren't working, it is difficult to determine how much or if the rods are melting.

In short - as at Three Mile Island in 1979 - nobody knows exactly what is happening. This leads to sometimes contradictory information being released while the overarching goal of both the company and the government is to prevent a panic.

The Prime Minister is angry at the company because of the spotty information coming into his office - liaison is apparently bad - and the press is angry because the government and the company can't get their stories straight.

The parallels to Three Mile Island are eerie. What President Carter eventually did was send a team from the NRC to take over both the management of the crisis and the PR duties. This appears to be what Prime Minister Naoto Kan is attempting to do now. The Guardian:

While both men called for calm, behind the scenes there were signs of the government's plummeting faith in the plant's operators, the Tokyo Electric Power Company. Kan was overheard reading the riot act to executives for failing to inform him of the blast, Japanese media said.

"The TV reported an explosion, but nothing was said to the prime minister's office for more than an hour," the Kyodo agency quoted Kan as saying. "What the hell is going on?"

Kan, who had already announced he would take personal control of a new joint-response headquarters involving the power company and the government, reportedly warned Tepco of serious consequences should it decide to pull its workers out before the plant has been made safe. "In the event of a withdrawal, I'm 100% certain that the company will collapse," he said. "You must be determined to solve this."

When Chernobyl blew up, more than 50 reactor staff died of radiation poisoning. Let's hope that this disaster doesn't get as bad as that.