Crews resort to last-ditch efforts to cool fuel rods

EMERGENCY workers frantic to regain control of Japan’s dangerously overheated nuclear complex turned to increasingly elaborate methods yesterday to cool nuclear fuel rods at risk of spraying out more radiation.

They tried with police water cannons, firetrucks and military helicopters dropping bucket after enormous bucket of water onto the stricken system.

By nightfall, it wasn’t clear if anything had worked, and the UN nuclear agency warned the situation was “very serious”.

US and Japanese officials gave differing assessments of what was happening at the Fukushima Daiichi nuclear plant, 220km north of Tokyo. The top US nuclear regulatory official warned of possible high emissions of radiation while the US ambassador urged Americans within 80km of the plant on the tsunami-savaged northeastern coast to leave the area or remain indoors.

Tokyo Electric Power Co, which owns the plant, said it believed workers were making headway in staving off a catastrophe both with the spraying and, especially, with efforts to complete an emergency power line to restart the plant’s own electric cooling systems.

“This is a first step toward recovery,” said Teruaki Kobayashi, a facilities management official at the power company. He said radiation levels “have somewhat stabilised” and some of the spraying reached its target, with one reactor emitting steam.

“We are doing all we can as we pray for the situation to improve,” Kobayashi said. Authorities planned to spray again today, and Kobayashi said: “Choices are limited. We just have to stick to what we can do most quickly and efficiently.”

Four of the plant’s six reactors have seen fires, explosions, damage to the structures housing reactor cores, partial meltdowns or rising temperatures in the pools used to store spent nuclear fuel. Officials also recently said temperatures are rising in the spent fuel pools of the last two reactors.

Two Japanese military CH-47 Chinook helicopters began dumping seawater on the complex’s damaged Unit 3 yesterday morning, defence ministry spokes- woman Kazumi Toyama said.

Chopper crews flew missions of about 40 minutes each to limit their radiation exposure, passing over the reactor with loads of about 2,000 gallons (7,500 litres) of water. Another 9,000 gallons (35,000 litres) of water were blasted from military trucks with high-pressure sprayers used to extinguish fires at plane crashes, though the vehicles had to stay safely back from areas deemed to have too much radiation.

Special police units with water cannons, however, could not reach the targets from safe distances and had to pull back, said Yasuhiro Hashimoto, a spokesman for the Nuclear And Industrial Safety Agency.

The dousing was aimed at cooling the Unit 3 reactor, as well as replenishing water in that unit’s cooling pool, where used fuel rods are stored, Ms Toyama said.

Tokyo Electric Power Co, said earlier that that pool was nearly empty, which would cause the rods to overheat and emit even more radiation.

Of concern is that Unit 3’s reactor uses a fuel that combines plutonium, better known as an ingredient in nuclear weapons, and reprocessed uranium. The presence of this mixed oxide fuel, or MOX, means potentially that yet another very harmful radioactive product could be released into the environment — plutonium.

US officials, meanwhile, said Unit 4 was also seriously at risk. A particularly dire warning came from US Nuclear Regulatory Commission chairman Gregory Jaczko, who told a congressional hearing in Washington that all the water was gone from that unit’s spent fuel pool and that anyone who gets close to the plant could face potentially lethal doses of radiation.

Yesterday, Jaczko told reporters it could be weeks before the crisis is brought under control.

He said the US recommendation that Americans stay 80km away from the nuclear complex was “a prudent and precautionary measure to take”.

That evacuation zone is far wider than that established by Japan, which has called for a 20km zone and has told those within 32km to stay indoors.

Tokyo Electric executives said yesterday they believed the rods in the Unit 4 pool were covered with water, but an official with Japan’s nuclear safety agency later expressed scepticism about that and moved closer to the US position.

“Considering the amount of radiation released in the area, the fuel rods are more likely to be exposed than to be covered,” Yuichi Sato said.

So just what is happening is unclear.

Graham Andrew, a senior official of the UN’s International Atomic Energy Agency, said the situation remained “very serious” but also noted that “there has been no significant worsening” at the plant over the previous 24 hours. He spoke to reporters yesterday shortly after IAEA chief and former Japanese diplomat Yukiya Amano flew to Tokyo to assess relief efforts.

Assessing what he called “the current situation” and citing NISA, Andrew said the fuel rods assembled inside reactor Units 1 and 3 were half covered by water, while the rods in Unit 2 were more than half submerged.

Mario V Bonaca, a physicist who sits on an advisory committee to the US Nuclear Regulatory Commission, said he believes the focus of the effort has shifted to the spent fuel pools.

“I understand that they’ve controlled the cooling of the cores,” said Bonaca, who said he was basing his understanding on NRC and industry sources.

The storage pools need a constant source of cooling water. Even when removed from reactors, uranium rods are still extremely hot and must be cooled for months, possibly longer, to prevent them from heating up again and emitting radioactivity.

While a core team of 180 emergency workers has been rotating in and out of the complex to avoid exposure, experts said anyone working close to the reactors was almost certainly exposed to radiation levels that could, at least, give them much higher cancer risks.

Experts note, though, that radiation levels drop quickly with distance from the complex. While elevated radiation has been detected well outside the evacuation zone, experts say those levels are not dangerous.

In Washington, the State Department warned US citizens to consider leaving the country and offered voluntary evacuation to family members and dependents of US personnel in Tokyo, Yokohama and Nagoya.

Nearly a week after the disaster, police said more than 452,000 people were staying in schools and other shelters, as supplies of fuel, medicine and other necessities ran short. Both victims and aid workers appealed for more help, as the chances of finding more survivors dwindled.

Noriko Sawaki lives in a battered neighbourhood in Sendai that is still without running water and food or gasoline supplies.

“It’s frustrating, because we don’t have a goal, something to strive for. This just keeps on going,” she said.