LATER UPDATE: Workers return to plant, resume attempts to restore electricity to Units 1 to 4 | LATE UPDATES: Gray smoke at Unit 3, workers 'temporarily evacuated' | Workers training to spray concrete to encase Unit 4...
By Brad Friedman on 3/20/2011, 11:59pm PT  

It's probably too early to breathe a full sigh of relief [Update: Apparently it is. See our late UPDATES at bottom of article.], but encouraging signs continue to come from officials concerning the state of the six nuclear reactors (and their accompanying spent fuel pools) at the badly damaged Fukushima Daiichi power plant in Japan.

"We are getting closer to bringing the situation under control," Deputy Chief Cabinet Secretary Tetsuro Fukuyama told reporters at a presser on Sunday evening (local time).

Hiroko Tabuchi and Norimitsu Onishi at The New York Times offered a decent, up-to-date round-up of the state of the various units at the power plant on Sunday afternoon (US time), as heroic workers continue their tireless, around-the-clock efforts to stave off catastrophe following last week's 9.0 earthquake, ensuing tsunami and subsequent series of explosions at the crippled plant.

With largely just one exception at this hour (though it's an important one), the status of each unit, as reported earlier today, still seems to be holding tonight, as Monday is well under way in Japan. As well, officials have offered a few more noteworthy pieces of news in the past hour or so. We'll hit each of those points, as mercifully briefly as we can, to get you up to speed for U.S. Monday, below...

As we reported yesterday, officials again confirmed that water pumps to Units 5 & 6 --- each of which had already been off-line for maintenance before the quake --- had been restored and the heat in the spent fuel cooling ponds in each has now returned to acceptably cool temperatures. As of this evening, power has been restored to both of them from the grid, and they are now in "cold shutdown". That's good.

"In general, our utmost efforts are producing definite results in preventing a worsening of the situation," according to Yukio Edano, the government's chief spokesperson, who then added --- perhaps in a bid for a promotion to Secretary of the Obvious --- that due to the heavy damage at the Fukushima Daiichi plant, it would be permanently closed after the crisis was finally over.

"Despite the positive tone from officials," NYTimes reports, "steep challenges persist. Workers were trying to avoid further damage to fuel rods in the reactor cores of Nos. 1, 2, and 3, and to prevent rods in the storage pools of Nos. 2, 3 and 4 from overheating."

Tokyo Electric Power Co. (TEPCO) officials said on Sunday that "workers injected 40 tons of water into the storage pool containing spent fuel rods at Unit No. 2, and that firefighters began spraying water into the pool at Unit No. 4. On Saturday, firefighters sprayed water at the storage pool of Unit No. 3 for more than 13 hours."

As we noted last night in several updates, not long after officials had initially declared the situation at Unit 3 to be "stabilized", pressure suddenly began rising again in the reactor vessel, and TEPCO officials said they might have to release radioactive steam again to ease the pressure. And not long after that, the pressure was determined to be "high" but had "stabilized" again, and so they called off plans to release steam.

Tonight, within the last hour or two, Japan's Nuclear Industrial Safety Agency (NISA) has once again reported that pressure seems to be rising in Unit 3 for unknown reasons, and, according to a Reuters "FLASH" on Twitter, they are "monitoring whether to take steps to release pressure by 'venting'" once again.

When hydrogen rich radioactive steam was vented last week, it met with oxygen and led to explosions at Units 1, 2 & 3, so its understandable that officials hope to avoid releasing pressure that way unless it becomes an absolute necessity.

Very late tonight, Voice of America's Steve Herman, who is on the ground in Japan, reports that authorities hope "by controlling water flow of spraying on Reactor 3 they could lower the pressure again, avoiding venting of gases."

A NISA official said late tonight, according to Reuters, that the agency "does not believe much water from no. 3 and no. 4 reactors is seeping underground." If true, that would be good too. We remain cautious about such statements at this early stage, however, particularly since so much of it includes a fair bit of guess work by officials who are unable to get close enough to the units, due to high radiation levels, in order to make detailed analyses.

TEPCO workers are still working to restore power to Units 1 and 2 --- after which they hope to splice the lines to deliver power to the other units --- though it remains unknown whether cooling system pumps will still work in any of the 1 through 4 units in light of the recent explosions, earthquakes and tsunami. Fukuyama said yesterday, optimistically enough, that it may take a number of days to replace broken parts in the cooling system.

NYTimes reports: "At least 25 workers and five members of the Japanese Self-Defense Force have been exposed to unsafe amounts of radiation, according to the power company. At least 20 workers and four self-defense soldiers have been injured, and two workers remain missing."

VOA's Herman notes tonight that the Kyodo News Agency is reporting that one of the nuclear plant workers was "exposed to radiation of 150 millisievert/hr." According to this helpful map of current radiation levels in Japan, as translated by Christopher Jones from data released by Yomiuri Shimbun, "we all receive around 2 millisieverts per year just from the natural background radiation". The worker who reportedly received a dose of 150 millisieverts per hour, is obviously in a precarious situation at this point, as are many of his heroic co-workers, most likely.

In the meantime, concern has turned to radiation discovered in food and water produced near the plant. The Japan health ministry has asked "some residents in the region of Fukushima nuclear plant to refrain from drinking tap water," though Fukuyama told reporters that he believed the levels posed no immediate health risks.

"At current levels, I would let my children eat the spinach and drink the water" from Fukushima, he said, before adding that his children did not drink much milk.

According to NYTimes...

Radiation contamination, meanwhile, appears to be spreading rapidly. The substances detected in the food products were iodine 131 and cesium 137, two of the more dangerous byproducts of reactor operations that are feared to have been released from the plants in Fukushima. If absorbed through milk and milk products, iodine 131 can accumulate in the thyroid and cause cancer. Cesium 137 can damage cells and lead to an increased risk of cancer.
...
Spinach from a farm in Hitachi, about 45 miles from the plant, contained 27 times the amount of iodine that is generally considered safe, while cesium levels were about four times higher than is deemed safe by Japan. Meanwhile, raw milk from a dairy farm in Iitate, about 18 miles from the plant, contained iodine levels that were 17 times higher than those considered safe, and milk had cesium levels that were slightly above amounts considered safe.

That's about where we are at this hour, in regard to the Fukushima Daiichi nuclear crisis. While things remain precarious, it certainly feels a bit more under control than it has been over the past nine days --- though things can obviously change quickly.

As things continue to stabilize --- if they continue to stabilize --- we may even be able to get back to covering a few other items of note, completely unrelated to Japan, many of which we've had to put off over the last week. So, for the moment, our fingers remain crossed...

* * *

UPDATE, 3/21 12:58am PT: Just in from CNN...

Tokyo (CNN) --- Officials were training workers Monday to spray the Fukushima Daiichi nuclear power plant's stricken reactors with concrete --- one of several efforts underway to curb the release of more radioactive material.
...
Those efforts include a move to possibly encase one or more of the reactors in concrete, a last-ditch effort similar to what was done after the 1986 meltdown at the Chernobyl nuclear plant in the former Soviet Union --- considered the worst nuclear disaster at a plant.

On Monday, an official with Japan's nuclear and industrial safety agency told reporters that tests are expected to be conducted in the afternoon on how to use what he called a "concrete pump engine."

The engine would pump a mix of mortar and water into the reactor's spent nuclear fuel pool and containment vessel, the official said
...
While he did not indicate when or even if the concrete pump would be used, the official did say the target would be the plant's No. 4 reactor. In just over two hours on Monday morning alone, 13 fire engines sprayed about 90 tons [of sea water] toward that reactor in an attempt to cool it down.

We have not been able to get much information since last week about Unit 4, where there is no fuel in the reactor, but spent fuel sits in storage pools which may be cracked. Officials have reported radiation levels were simply too high to get near it, so they've been unable to offer information publicly. The lack of information has worried some that officials may not be sharing all that they know. The suggestion that they may be getting ready to encase it in cement does not bode well for what may be happening right now at that unit.

UPDATE 3/21, 1:09am PT: And things get worse again. Let's hope it's only temporarily so. The Daily Yomiuri has just announced: "TEPCO says it has evacuated workers from Fukushima nuclear power plant after gray smoke seen coming from No. 3 reactor." As we reported above, that is the reactor where the pressure had reportedly been rising earlier tonight, and where officials had been spraying tons of sea water, for hours on end yesterday, in hopes of replenishing the spent fuel pools and cooling the spent fuel rods inside of it.

UPDATE 3/21, 1:53am PT: An official with Japan's Nuclear Industrial Safety Agency (NISA), Hidehiko Nishiyama, just gave a press conference on the smoke and evacuation of workers from near Unit 3. He said that at approximately 3:55pm local time, black and then gray smoke was seen coming from the south-east side of the reactor building, near where the spent fuel pools are located, though it was not clear that the fuel was the cause of the smoke. No blasts were heard, and the cause of the smoke remains under investigation. He said no work was yet being done to restore electricity to that building, so he did not believe that the smoke was caused by a short circuit. While white steam or vapor has been seen emanating from the building in the past, this is the first report of "black or grayish" smoke coming from Unit 3. Last week a hydrogen explosion at Unit 3 blew off the roof and upper walls of the reactor building.

In a press conference held moments later by chief government spokesperson Yukio Edano, he said that radiation levels do not appear to be increasing at the plant and that there are all sort of flammable objects in the building, so they continue to investigate the cause of the smoke. He reiterated that he did not know if the smoke was related to the spent fuel storage pools, but because radiation levels were not rising he did not feel the situation was "turning for the worse."

Late reports say that the gray smoke has decreased a bit since it appeared initially.

UPDATE 3/21, 3:01pm PT: Have not yet been able to find a later update today concerning the status or cause of the gray smoke reported last night at Unit 3 beyond VOA's report, published within the last hour, that "Officials said the smoke dissipated after about half an hour, but white smoke or vapor was detected coming from the number 2 reactor."

And this, from Nikkei, also within the last hour, on the workers evacuated last night as the smoke appeared:

The Nuclear and Industrial Safety Agency said it would decide by midday Tuesday whether to restart work at the plant.

At a news conference, Tepco Executive Vice President Sakae Muto apologized to the public. He said the company is putting safety first as crews operate in the face of tough conditions.

"Midday Tuesday", or noon, in Japan would be at approximately 8pm PT, or 11pm ET. We will, of course, update as warranted.

UPDATE 3/21, 9:20pm PT: The Daily Yomiuri reports: "After stopping work 16 hours ago because of smoke from reactor 3, workers are back trying to restore electricity at the Fukushima N-plant. ... TEPCO says the 'smoke' coming from reactor 3 is actually steam and has judged it is safe for workers to return to the area."

And VOA's Steve Herman reports the Kyodo news agency confirms: "Work to restore power at No. 1-4 reactors at Fukushima nuke plant resumed."

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We will continue to post breaking updates and related news items, as they happen around-the-clock, on our Twitter account at http://Twitter.com/TheBradBlog.

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Article Categories: Environment, Japan