True, a plume of what appeared to be white smoke rose from two reactor units on Monday, causing workers to evacuate the area and sending a shiver of concern around the world.
But the smoke apparently was not accompanied by any rise in temperature or radiation readings, according to US officials. If subsequent measurements confirm this assessment, that is good news.
Plus, Japanese workers were close to restoring electricity to the plant after stringing what amounts to a very long extension cord to the area from the nearest live power grid.
“In my view, the fact that off-site power is close to being available for use of plant equipment is perhaps the first optimistic sign that we’ve had things could be turning around,” said Bill Borchardt, US Nuclear Regulatory Commission executive director for operations, at a Monday meeting of the NRC outside Washington, D.C.
Containment vessels not breached
Mr. Borchardt, in one of the most detailed assessments yet made public about the crisis at the Fukushima site, said that in the NRC’s view none of the six primary containment vessels at the complex had been breached in the aftermath of the twin natural disasters that struck northeast Japan on March 11.
The situation at the spent fuel pools at reactors three and four is “stabilizing,” said Borchardt. That would mean that the efforts of Japanese firefighters and soldiers to pour water through damaged buildings into the pools may be paying off.
That’s important because these pools “were of significant safety concern,” Borchardt told NRC commissioners. Radiation releases at the site may have come primarily from fuel rods in these pools after they lost water following the quake and tsunami, he said.
Right now, the electrical power that workers are bringing into the plant has essentially reached the border between units one and two, according to the NRC. Japanese workers are now laying temporary wires into the containment buildings to bypass cabling problems they’ve discovered.
New pumps on order
In Japan, officials of Tokyo Electric Power said that some of the pumps inside the most damaged reactors no longer work. They have ordered new pumps, which circulate coolant inside the reactor buildings, but the delivery schedule for these is unknown.
If the Japanese workers can get the power and lights back on and restore enough pumping capacity to get enough seawater into the reactors and spent fuel pools, temperatures at these units would be back within safe limits in a few hours, according to Japanese officials.
Given all that has happened, they just cannot predict when that moment will occur.
“We have experienced a very huge disaster that has caused very large damage at a nuclear power generation plant on a scale that we had not expected,” said Hidehiko Nishiyama of the Nuclear and Industrial Safety Agency in Japan.
Once temperatures have stabilized, the next big step will be determining the extent of damage within the containment buildings, some of which have themselves been damaged by hydrogen gas explosions.
Damage to reactor fuel
At least some reactor fuel has been damaged. That is something on which most experts agree. But whether the damage can be repaired, or whether the reactors must be permanently shielded in some manner, is another question.
“Once power is restored, we’ll have some idea whether [Japanese officials] can get this under control or whether we are heading toward entombment,” writes Jeffrey Lewis, Director of the East Asia Nonproliferation Program at the Monterey Institute of International Studies, on his “ArmsControlWonk” blog.
And the next worrisome development in the unfolding nuclear crisis may be contamination in Japan’s food supply.
Traces of radiation have tainted vegetables grown on farms in the region and milk from cows that were fed contaminated plants.
The Japanese government has already banned sales of raw milk, spinach, and canola from prefectures in a swath from the Fukushima plant south toward Tokyo.
The Geneva-based World Health Organization says that Japan must act quickly to stop sales and shipment of affected food because ingested radiation can accumulate in the body and thus poses greater long-term health risks than radioactive particles floating in the air.
“They’re going to have to take some decisions quickly in Japan to shut down and stop food being used completely from zones which they feel might be affected,” World Health Organization spokesman Gregory Hartl told the Associated Press on Monday.