The workers are cut off from the outside world in a stricken plant where even the telephone lines have been disconnected. A crack was reported in the roof of the reactor building late today, and technicians are racing against time since Friday's earthquake and tsunami to prevent serious damage to three reactors and the spread of life-threatening radiation. Two workers were reported missing after today's explosion, officials said.
"They're taking action, they're fully engaged and they know they're saving lives. They might need help for trauma later on, but right now they know they're doing the right thing," he said.
But as Japan and the rest the world worry about possible meltdowns and fluctuating radiation levels, the workers are risking their lives amid dangerous hydrogen explosions and fires that have already injured seven of them.
Today, the levels of radiation at the plant, though they have since fallen, measured a dangerous 400 millisieverts.
To put that into perspective, the average annual dose limit for nuclear power plant operators in many countries is just 20 millisieverts, and most don't absorb more than 1 millisievert in a year, said Jonathan Billowes, a professor of nuclear at the University of Manchester.
Billowes, like many nuclear physicists and nuclear energy experts interviewed by AOL News, has limited data about the exact situation in the Fukushima plant, but he said certain protocols are followed all over the world.
At Fukushima, however, some of the workers are personnel who have probably never been inside a nuclear power plant before. They are the teams in charge of the fire trucks used to pump hoses full of seawater into the reactors to try to cool them and avert a meltdown. The plant's diesel generators were knocked out by the tsunami and caused the reactors' cooling systems to fail.
Both the emergency responders and the plant technicians are working with the help of two or three people thought to still be in the plant's control room, as well as a special operations center relocated off-site.
"I've worked around radiation, and it's scary," Stanton Friedman, a retired nuclear physicist with General Electric, told AOL News today.
"You try to be careful, but it sure isn't easy and it sure isn't fun. These people are working a disaster within a disaster. They got clobbered. First the earthquake, then the tsunami took out their generators. You can be sure they feel a huge sense of responsibility to fix this, but they are in a tough spot. They're professionals, but they're probably terrified too."
About 170,000 people within a 30-mile radius of the plant have been evacuated. The U.S. today recommended that personnel and families stationed at two bases in Japan take precautions after detecting low-levels of radioactivity, including staying inside. Japan has announced an 18-mile no-fly zone around the plant to prevent planes from spreading the radiation farther afield.
But the workers at the plant have little protection.
"They're liable to receive high doses of radiation," said Sean Freeman, a professor of nuclear physics at the University of Manchester in the U.K. "They will have to be closely monitored once this is all over."
More than 850 nonessential personnel have left the plant's control room and other areas of the facility, and those who are left are "having to work outside the box in conditions they never expected," said Lawrence Criscione, a former senior reactor operator at a nuclear power plant in .
"The worst place to be is near the reactor when you're trying to open some vents," Criscione said. "That's stressful because that's when hydrogen explosions can result."
And even though television viewers see men in white hazmat-type suits and gas masks directing traffic around the Fukushima plant, the technicians inside don't have the luxury of such gear because it can get too hot and cumbersome.
"They'll be wearing reasonably protective gear, but if you wear too much you'll have a problem with heat exhaustion," said John Sutherland, the former senior physicist in charge of radiation protection at Point Lepreau nuclear facility.
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"They will also be wearing very good radiation meters at all times, with radiation badges. Based on the radiation levels showing up on those devices, they figure out how long they can work in a certain location before regrouping and moving back for a while," he said.
But the Fukushima workers may be benefiting from the 1979 nuclear disaster at Three Mile Island, where human error in part led to a partial core meltdown at one reactor.
"For the first two or three hours, the guys in the control room at Three Mile Island denied what was happening," Perchet said. "A new guy came in for his shift, and that got them slightly back on track, but those first couple of hours were crucial."
Perchet said initial denial on the part of reactor operators is always a possibility.
"Some of the workers in Japan could even be denying to themselves how bad a situation it could be," he said. "It's human nature in this kind of high-stress, dangerous situation. At the same time, these guys are like the firefighters at the World Trade Center."
"It's helped enormously in countering what we call 'the wrong stuff,'" Perchet said.
The crisis at the Fukushima plant, which contains six nuclear reactors, has mounted since the post-earthquake tsunami knocked out the cooling systems. Explosions rocked the structures housing reactors No. 1 and 3 on Saturday and Monday. This morning a third blast hit reactor No. 2's building. A fire also broke out at a spent fuel storage pond at the power plant's reactor No. 4 before being extinguished.