IWAKI-YUMOTO, Japan — Most residents of Iwaki-Yumoto are still fast asleep when the first stirrings of human activity join the din of crows picking through garbage bags.

The men who emerge from their hostels and inns, blinking when confronted by the dazzling early-morning sun, say little as they board waiting buses, the only traffic around at 6 a.m. in this hot-spring town of 30,000 people, located just 30 miles from the Fukushima Dai-ichi power plant.

Within a couple of hours they will be doing jobs that few others would be prepared to even consider; yet it is to the hundreds of workers in Iwaki-Yumoto whom Japan is looking to help solve the worst nuclear accident in its history.

Prime Minister Naoto Kan announced today that the plant has been stabilized and will be prepared for a cold shut down within the next six months. Though there have been conflicting messages in the past as to what constitutes progress in the clean-up effort, this appears to be the best news in some time.

In addition to 373 staff employed by the plant's operator, Tokyo Electric Power (TEPCO), the Fukushima Dai-ichi plant is teeming with 2,529 contract workers, all braving dangerously high radiation on what must be the most hazardous industrial site on earth.

Many of them have taken up temporary resident in Iwaki-Yumoto, lured by the promise of guaranteed work during another economic downturn, and wages that, while not high, are better than average.

They are the modern day "nuclear gypsies," as described in Kunio Horie's 1979 book of the same name — largely unskilled and untrained laborers on whom Japan's utilities have depended for cheap labor since the nuclear power plant building boom of the 1970s.

Ariyoshi Rune isn't altogether comfortable with that description. The 47-year-old truck driver began working at the Fukushima plant at the beginning of June after answering an ad in a recruitment magazine in his native Kyushu in Japan's southwest.

He is phlegmatic as he described the conditions at Fukushima Dai-ichi between gulps of beer and long drags on a cigarette. His daily wage of 12,000 yen is, he says, fair remuneration for his efforts, even though skilled TEPCO employees earn an average of 7.6 million yen a year. "I think my wage is fair for the kind of work I do. It's more than I used to get driving a truck."

Besides payment, Rune and the 24 other men on his cleanup crew receive free accommodation, three meals a day and transport to and from their hotel.

Like many of the other contract workers, he has not been totally honest about the nature of his work with members of his family. "When I told my children about my work the first thing they said was, 'Please don't get irradiated,' said Rune, who is part of a team that is removing and packing 23,000 firefighters uniforms, dumped near Fukushima Dai-ichi's crippled reactors in the first days of the crisis.

"They worry, but they also think that what I'm doing is kind of cool." His 73-year-old mother knows he is working in the Fukushima area, but has no idea his job takes him to the power plant for several hours a day.

The president of a construction firm based in Hokkaido in Japan's far north says about half his 40 employees refused to work in Fukushima, citing opposition from families worried about the long-term effects of prolonged exposure to radiation.

"Our employees can earn about double their 350,000 yen salary working at the plant," said the president, who asked for the name of his firm to be withheld. "As a company, we have lots of extra overheads, such as transport and accommodation, so we're not going to make much money from this, however long it drags on."

The laborers' working day begins at 8 a.m., and ends at about 1 p.m., their two 90-minute shifts separated by a break of similar length when they are served a lunch of curry and rice, bottled water and tea, jelly and candy.

"There isn't enough room to get your head down for an hour during breaks," says Rune, "But there are more toilets and drinks and more space for relaxing."

The estimated 9,000 men and women who have worked at the Fukushima plant since it was badly damaged by the March 11 tsunami have more reason than anyone to worry about their exposure to dangerously high levels of radiation.

At least nine have exceeded the annual exposure limit of 250 mSv, an unusually high threshold introduced in the wake of the disaster to allow TEPCO engineers more time in the most hazardous parts of the complex. According to international guidelines, in normal circumstances nuclear workers must not be exposed to more than an average of 20 mSv a year.

But with Japan now well into the hot and uncomfortably humid months of summer, it is the heat, not contamination, that contract workers say they fear most.

"Radiation doesn't bother me, but I am worried about falling ill because of the heat," says one man, a 34-year-old from the western city of Osaka who declined to give his name. "It is unbelievably hot inside those suits. I know of several people who've been taken ill on the job."

Last week TEPCO conceded that as many as 31 workers had fallen sick with heatstroke. The utility has attempted to improve conditions at the site, including the introduction of shorter shifts, more resting spaces and the distribution of coolant vests and refrigerant packs.

"We are very concerned about the health of all the workers on site and have taken appropriate measures to protect them against the heat," said Yoshikazu Nagai, a TEPCO spokesman.

But the measures do little to mitigate the effects of working in high temperatures dressed in masks, protective suits sealed with tape at the ankles, wrists and neck, gloves and personal radiation monitors they must carry with them at all times.

Experts have also warned of the psychological impact of being engaged in such high-risk work, often in defiance of anxious relatives, along with the relentless pressure to complete the cleanup and bring the reactors to a safe state known as cold-shutdown by TEPCO's self-imposed deadline of January.

"Their level of stress is unimaginable," said Takeshi Tanigawa, a professor of public health at Ehime University, adding that, without counseling, some were at risk of developing post-traumatic stress syndrome. TEPCO has since acknowledged that the risk of radiation exposure and concern among relatives has created "multiple" sources of stress for Dai-ichi workers.

At this time of year, local hoteliers and inn owners would normally be inundated with tourists and weekend visitors eager to soak in the area's therapeutic spring waters.

But due to radiation fears, and an influx of about 1,000 nuclear refugees and 2,000 contract workers, tourism has dried up.

"The inn owners are pleased to be fully booked for months ahead, but they are beginning to worry about how long this will go on for," said Katsue Takahashi, an Iwaki city official. "With the evacuees here, too, no one wants to come here for a holiday."

Koichi Ando, whose traditional-style inn has been home to hundreds of railway engineers and police officers since the tsunami, said: "We reckon the situation will stay like this for at least another three years, and that it will be 10 years before we see the first tourists arriving."

But Japan's prime minister, Naoto Kan, has since said it may be 10 years before work can even begin decommissioning the reactors, a dangerous process that could last several more decades.

Rune's daily brush with radiation could force his departure well before the cleanup has ended. After about five weeks on the job, checks revealed he had been exposed to 5 mSv a year; company rules dictate that contract workers who are exposed to 15 mSv — or 30 mSv for full-time staff — can no longer work at the plant.

"I have about two months left before I reach my limit, but I'm hoping they'll make an exception and let me work for longer. I've never thought my job was dangerous."