Fukushima 16 April 2011

Well our friends the Japanese have screwed the pooch again. They forgot to turn on the water.

“The Fukushima Daiichi nuclear power plant in Japan emitted a new burst of radioactive material this week after a bungled cooling effort apparently affected spent atomic fuel in the site’s No. 4 reactor cooling pond, the Associated Press reported.”
“Workers were firing water into the pond from a distance in an effort to prevent the fuel from overheating and releasing radioactive contaminants, but fluid collecting in an adjacent flood control container triggered an incorrect warning that the pond had been filled. Personnel halted water transfers to the pool for a number of days in response to the warning, allowing heat and radiation levels to increase even though the fuel was thought to have remained submerged, Japanese Nuclear and Industrial Safety Agency Deputy Director General Hidehiko Nishiyama said. Water spraying began again on Wednesday.”

I dunno. When I was a Naval Nuke and we got into emergency situations (an unexpected scram say) we always sent a man to check that what our instruments were telling us was correct. Things like – is the emergency diesel generator actually running? Now maybe they were short handed (it was a commercial operation after all) when the accident started. But it is a month on. There should be plenty of hands on deck.
In other bad news it seems that they are worried about further earthquakes.

Acting on a government order issued on Wednesday in response to the more recent smaller earthquakes, Tokyo Electric Power began studying the ability of reactor structures at the facility to withstand additional tremors, Kyodo News reported. The company must inspect plant components and weigh repairs to any vulnerable areas, the atomic safety agency said.
Still, the operator warned it might not “immediately conduct an investigation” due to potential risks around areas slated for inspection (Kyodo News I).
Personnel were looking for damage to walls, floors or pipelines at the plant’s main waste treatment area and in other sections where radiation-tainted water has collected, the Asahi Shimbun reported.
The primary worry, though, was the potential for new tremors to cut off electricity to pumps being used to move coolant into the site.

The “potential risks” for inspectors means very high radiation levels.
The Union of Concerned Scientists [pfd] (a bunch of lefties but occasionally their thinking is not corrupted by politics) in Congressional testimony asks why reactors have multiple levels of containment and the spent fuel pools are more or less open air.

After being discharged from the reactor core, the irradiated fuel awaits transfer to a federal repository, which does not yet exist. The United States has spent more than ten billion dollars on a proposed repository at Yucca Mountain in Nevada. The Department of Energy faces an immense engineering challenge siting a repository because that location must isolate irradiated fuel from the environment and inadvertent human intrusion for at least 10,000 years into the future, or merely 42 times longer than we have been the United States of America.
Between those two time periods–when irradiated fuel is treated as a highly hazardous material and nuclear plant owners and the U.S. government undertake expensive and extensive efforts to protect the American public from this material–irradiated fuel sits in temporary spent fuel pools with almost no protection. For unfathomable reasons, irradiated fuel is considered benign after it is taken out of the reactor core and before it is placed in a repository.
Today, tens of thousands of tons of irradiated fuel sits in spent fuel pools across America. At many sites, there is nearly ten times as much irradiated fuel in the spent fuel pools as in the reactor cores. The spent fuel pools are not cooled by an array of highly reliable emergency cooling systems capable of being powered from the grid, diesel generators, or batteries. Instead, the pools are cooled by one regular system sometimes backed up by an alternate makeup system.

They are a bit hysterical about 10,000 years. It is more like 500 years. In any case it is quite a long time for any civilization. We need to give these spent fuel pools a lot more attention. And protection.
The Japanese are getting something right. They are doing high level atmospheric monitoring.

Fukushima University is checking radiation levels high in the atmosphere to get a better grasp of the extent of contamination from the troubled Fukushima Daiichi nuclear power plant.
The university says it released a large balloon on Friday carrying a weather observation device called a “radiosonde” as well as radiation measurement equipment into the skies above Fukushima City.
It plans to gauge radiation levels and collect other data up to 30 kilometers above ground. Readings will be taken at intervals of 10 meters over a period of 20 days.

This will also give some idea of what potential there is for radioactive particle transport across the Pacific (a lot or a little). It would also be nice if they did some monitoring out to sea. Maybe as they get more organized they will do that.
As you might expect there are other problems. Like water water everywhere and no place to put it.

It is still difficult for the Tokyo Electric Power Company to determine when the work to restore reactor cooling systems at the damaged Fukushima Daiichi nuclear power facility will begin. The company says more time is needed to install makeshift water tanks in order to contain the highly radioactive water used to cool the reactors.
The contaminated water has pooled inside turbine buildings and tunnels, hampering efforts to restore reactor cooling systems. Removal of the wastewater is necessary before restoration work can begin.

Ah. Yes. Restoration work. Once they are set up the work is expected to go quickly. But they are quite far from being set up.

Japanese nuclear scientists say if a cooling system can be put in place at the Fukushima Daiichi plant, stabilizing its nuclear fuel could take another 3 months.
The deputy head of the Atomic Energy Society of Japan, Takashi Sawada, released the projection by an informal group of 11 society members on Thursday.
He said data published by Tokyo Electric Power Company shows that parts of the fuel rods in reactors 1 and 3 have melted and settled at the bottom of the pressure vessels.
He said if the ongoing water injections continue, the current situation can be maintained.
He said Tepco’s most important task is to remove all the contaminated water and rebuild a cooling water circulation system.
He said once these jobs are done, stabilizing the nuclear fuels could take 2 to 3 months, if not longer.
But he warned that the situation could deteriorate if another strong earthquake knocks out power to the plant and makes it impossible to keep the nuclear fuel cool for 2 or 3 days.

Evidently they don’t even need earthquakes. Operator error will suffice. And note the big IF.
It seems that there have been some bad feelings about the situation that the Government declined to announce.

“After the explosion of Reactor 1, we [the government, TEPCO] wanted to prevent hydrogen explosions but had no means of doing so. We thought it [hydrogen] leaked from the Containment Vessel and it was the core meltdown, but we just didn’t feel like announcing that.“

I have a bad feeling about that. What else are they failing to announce? It makes ya wonder. And worry.
Ever wonder what the TEPCO folks mean by low level radiation? I have. It appears we have an answer.

The amount of low level radioactive wastewater discharged to the sea this time was approx 9,070 tons from the Central Radioactive Waste Disposal Facility and approx 1,323 tons from the sub-drain pits of Units 5 and 6 (Unit 5: approx 950 tons, Unit 6: approx 373 tons). The total radiation discharged was approx 1.5 x 10^11 Bq.

I think we should do some math. Let us start with volumes – 9,070 Tons + 950 Tons + 373 Tons = 10,393 Tons. Multiply by 1,000 liters per ton (assuming fresh water) gives you 10,393,000 liters. Divide that into the amount of radiation and you get 14,433 Bq/l. Given the uncertainties 10,000 Bq/l is probably a good enough number. I wonder what they would consider “high level”?
I will have more gloom and doom for you when I do a post on what the radiation releases from Chernobyl have done to the health of the populations affected.
Revised: 16 April 2011 2157z
I did the calculations wrong. I forgot some 9,000 Tons of water. If you have an old copy, copy this one over it or save it for laughs.
Cross Posted at Power and Control