Journalism in the Public Interest

Spent Fuel Now Focus at Japanese Reactor, Highlighting Concerns About Plant Design

As ProPublica reported earlier, spent fuel stored outside the reactor containment structure poses a direct threat of radiation releases at Japan’s stricken Fukushima Daiichi nuclear power facility.


(JIJI PRESS/AFP/Getty Images)

As we reported yesterday, spent fuel rods at Fukushima Daiichi pose a risk of fire and radiation release should water drain from the pools they are stored in.

Spent fuel now appears to be a problem at Fukushima’s reactor No. 4, where there was a fire early this morning.

Japan's NHK World TV reported the problem late Monday, as did the New York Times:

But late Tuesday, Japan's nuclear watchdog said a pool storing spent fuel rods at that fourth reactor had overheated and reached boiling point and had become unapproachable by workers at the plant. The fire earlier Tuesday morning was sparked by a hydrogen explosion generated by rising temperatures at the fuel pool, which released radioactivity directly into the atmosphere.

The fourth reactor had been turned off and was under refurbishment for months before the earthquake and tsunami hit the plant on Friday. But the plant contains spent fuel rods that were removed from the reactor. If these rods had run dry, they could overheat and catch fire. That is almost as dangerous as the fuel in working reactors melting down, because the spent fuel can also spew radioactivity into the atmosphere.

Shigekatsu Oomukai, a spokesperson for the Nuclear and Industrial Safety Agency, said the substantial capacity of the pool meant that the water in the pool was unlikely to evaporate soon. But he said workers were having difficulty reaching the pool to cool it, because of the high temperature of the water.

This diagram shows where spent fuel pools are located in the boiling water reactor system at Fukushima, a 1970s design by General Electric known as the Mark 1. As the graphic shows, while the spent fuel lies under a deep pool of water, it is outside the concrete-and-steel containment designed to trap radiation leaks.

GE defended the reactor design in a report by the Washington Post:

"The BWR Mark 1 reactor is the industry's workhorse with a proven track record of safety and reliability for more than 40 years," GE said in a statement. "Today, there are 32 BWR Mark 1 reactors operating as designed worldwide. There has never been a breach of a Mark 1 containment system."

The Associated Press and other news media reported rising radiation levels from Fukushima. Reactor No. 4 had been shut for maintenance before the quake and tsunami, the AP said:

Japanese officials told the International Atomic Energy Agency that the reactor fire was in a storage pond and that "radioactivity is being released directly into the atmosphere. Long after the fire was extinguished, a Japanese official said the pool, where used nuclear fuel is kept cool, might be boiling.

"We cannot deny the possibility of water boiling" in the pool, said Hidehiko Nishiyama, an official with the economy ministry, which oversees nuclear safety.

The Times said spent fuel posed a long-term danger at Fukushima Daiichi. Should spent fuel catch fire:

"It's worse than a meltdown," said David A. Lochbaum, a nuclear engineer at the Union of Concerned Scientists who worked as an instructor on the kinds of General Electric reactors used in Japan. "The reactor is inside thick walls, and the spent fuel of Reactors 1 and 3 is out in the open."

Voice of America reported:

The International Atomic Energy Agency said it was informed by Japanese authorities that the fire took place at a storage pond for spent fuel rods at the plant's number 4 unit, and that radioactivity was released directly into the atmosphere at dose rates equivalent to 4,000 chest X-rays every hour.

The latest report from the IAEA suggests radiation levels may be falling.

Leda Beth Gray

March 15, 2011, 8:23 a.m.

You are missing some wording from the second paragraph or is that just something my iPad can’t deal with?

J. B. Lisankis

March 15, 2011, 8:38 a.m.

The writer states that letting the spent fuel storage pools run dry is “ALMOST as dangerous” as letting the fuel in a working reactor over heat.  In actuality, this is probably a far more serious situation because the fuel still packs enough criticality to reach a chain reaction state, and it is NOT contained in anything more significant than the pool of water used to keep it cool.  No water, and you have an open air meltdown situation.

What kills me? The way people think.

OK - you’ve got a nuclear reactor. One thing you have to be able to do at all costs: Keep the fissionables cool. You must have cooling water available. These people know that, so they build ‘em next to lakes, rivers, even the ocean - as close to an unlimited supply as this planet has to offer.

So why haven’t they taken the obvious step, and made the most critical point of failure keeping water out??  I.e., a power failure to critical components de-energizes relays holding sluice gates closed - which upon springing open permits the adjacent lake, river, or ocean to rush in and swamp the fissionables?

Like I said, the way people think kills me. Unfortunately, the way they think kills a lot of other people, too, and much more literally.

New Zealand News3 is reporting that it is “unlikely” that radiation could reach the west coast of the U.S.  That it would take a large fire with the smoke carriing the radiation high into the atmosphere.  Thier expert went on to say that even in that case it is likely that the particles would be so widely dispersed that they would not be at the concentration levels that pose a threat to human health. 

Is “a chain reaction” the melt-down of one reactor causing the damage/melt-down of the other nearby reactors?  Does that include only the building housing the most damaged four, or are the three reactors in the other building included in the chain reaction?

Can a fire within these “spent fuel” pools, that are exposed, cause enough atmospheric radiation that it poses a risk to the U.S.?  The link provided in the story suggests (if I understand it correctly) that they use a method of storage that is less than optimal for safety.  That the amount of radioactive waste in the storage pools is quite high.  In fact, it seems to say that the storage pools are all kept full, at all times (“only removing” spend fuel to make room). Since the spent fuel contains this NK (that is so dangerous to our health) these pool-fires, and the smoke from them, are spreading severely toxic matter far and wide. ? 

I also wander how, with out pumps, they are disposing of the heated water to make room for the cooling water.  Is this being dumped into the ocean? Does Greenpeace know this? 

Did the explosion in building #3, that apparently distroyed the top of the outer housing, send the contents of the #3 storage pool to God-knows-where? The link in the diagram, as well as the imformation that the pools are located above the reactors, suggests that more than “some” of the water from the storage pools “might” have spilled.  And then there is the iodine tablets being distributed, to reduce the absorbtion of radioactive iodine (by the Thyroid).

NOTHING that I say is expert, nor is it likely to be right, so don’t take it in any other light than that.  I’m just trying to think this through, maybe pose a question or two that Propublica might want to try and answer.  If I am wondering, then I think others may be also.

Thank you for this article, as well as the previous ones on what is happening in Japan.

CNN and News3NZ are reporting that the Fukushima Nuclear Complex has been abandoned due to rising radiation levels.  It must be unbelievably terriffiing in N. Japan.

Spent fuel is stored in assemblies built so that the rod spacing assures sub-criticality. When the water drains away any stray neutrons from spontaneous fission do not moderate and could only be captured by U238 or some other metal in the assembly. What is dangerous is the decay heat leading to fuel cladding rupture and release of fuel pellets and the thermal driven evaporation of fission products into the air. That would make the spent fuel pool gantry and other spaces deadly to be in.  In this whole episode I hope the news hawks will keep close track of all those Fukushima workers and how their health evolves.

The thought of more nuke plants is getting scary, ain’t it? Don’t sit there worrying - do something about it.

Join the Clean Energy Project and use the idle time of your computer(s) to get us off oil (and so the Middle East) and avoid the need for nuclear plants in your backyard.

Watch the tutorial at

Remember: The best defense is a good offense.  Spread the word - save the world.

The health of the plant personel, the original 700 and the final 50, is in serious jeapordy. It is unbelievable that they continued to perform thier jobs in these circumstances. I don’t think we need to study the effects… it really could not have changed much in the last 65 years.

It doesn’t seem to permeate the minds of the people I come across, that there is a very high price paid for wasted resources.  Even without this slowly spreading disaster. They are stealing from the future.  I equate it to an epidemic of immaturity.  What ever is acceptable amoung thier social piers, or public idols, is enough to make them feel they do thier part. Remodel, but install bamboo floors (those old oak ones aren’t renewable, throw them out), never considering that they had to be shipped from China. Isn’t it cool to be Green!  I don’t have enough faith in the human race to believe that efforts to save the world will work.  I just try to slow down the process. It makes me sick to watch what people do in the name of “need”.

I’m not for nuclear, nor against it, completely.  I just prefer solar because I have some understanding of it.

The zoning laws in the U.S. keep us addicted to the automobile.  You have to have a car to get your milk home before it spoils, and no way can you have a chicken for eggs.  Strange that I can keep my parrot who tortures the nieghbors if he hears another bird outside.  They need to close thier doors anyway, to keep the heat in.

Public transportation in most places is scary and sometimes dangerous.  When you get within half a mile of your destination you’re dumped out at a major intersection, only to weave your way through a mase of moving steel and fouled air.  If you are what you drive you must be worth very little if you walk in Ca. Riding a bike will leave you with PTSD. Best not to go out to much if you want to save gas. You might get in someones way.

Makes me think, the Japanese have an an amazing patience. SoCal could really learn some social skills fro them.


Has anyone tryed to make the public aware of how the zoning laws effect energy consumtion?  I know of one book “The Geography of Nowhere”, but I can’t seem to get anyone interested enough to read it.  Nobody seems to get the connection between the sprawling suburbs and our massive consumption of energy.  The economist view continues to be more “housing starts” and we will all be fine.

Duwayne Anderson

March 16, 2011, 11:31 a.m.

Okay, this may be a dumb question—but here goes.  If you take an open bowl of water and subject it to vigorous shaking, the water will slosh about, and some (sometimes a lot) of the water will slosh over the edge, partially emptying the bowl. 

Does anyone know if the pools holding the spent rods were covered?  If not, I’d expect the earthquake to easily setup resonant waves in the pool that would slosh over the edge and partially empty the pools.

Please tell me it couldn’t actually be that easy—that the designers thought of that contingency and designed a solution for it.

@ProPublica,  Duwayne Amderson,  Leda Beth Grey,  ibsteve2u,  J. B. Lisankis,  John Fernan

Exactly!!!!  I looked at the diagram in the link above, a simplified section, can that be right?

Right now the Senate is holding a hearing on the safety of this design and the overall safety of nuc plants in the U.S.  Whether pro or con on nuclear energy we have a chance right now to improve the safety of our current nuc power plants.



Please consider providing links to the Senate Cmte on Enviroment and Public Works.


March 19, 2011, 4:31 p.m.

Diablo Canyon Nuclear Power Plant Memories

[“We cannot deny the possibility of water boiling” in the pool, said Hidehiko Nishiyama, an official with the Japanese economy ministry, which oversees nuclear safety.]

This statement is incredible!  “...the ECONOMY ministry, which oversees nuclear safety.”  It sounds as though a department of bean-counters acting as middle men for the occupational safety and health administration.  I can just see it now, the economy ministry red-lining a requisition for superior strength thing-a-mabobs and replacing it with lowest-bidder thing-a-mabobs.  Is it any wonder, in a manner of speaking, that units 1 thru 6 are slowly sliding into the sea?

Why are bean-counting individuals and organizations interesting?  Our offset printing company in San Luis Obispo, California, bartered accounting services with an accountant that worked full-time at Diablo Canyon Nuclear Power Plant (10 to 12 miles from SLO).  Oh, the stories he told ... they’d make the hairs on the back of your neck stand up on end!  To this day I still get chicken-skin thinking about the cost-cutting and thriftiness of the contracting firms on site.

By the way, “Diablo” translates to Devil in English.

San Luis Obispo is a smallish community and ‘word’ gets around sooner or later.  Being protesters ourselves, we did our best to share the latest information about the “Unclear Power Plant” (a modified billboard as visitors departed SLO).  For example when the builders ‘discovered’ that Unit 2 was constructed backwards from mirror-image blueprints—the NRC rubber-stamped this gross error too—as the builders wondered why all the writing was reversed (see for even more ‘discoveries’).  How about a second earthquake fault only 1 mile offshore, and the after-operation structural reinforcements being put in backwards!  Nevermind about the alcoholism, drug busts, or the near meltdown event halted by a geeky control room operator.

The good people of San Luis Obispo County—just trying to protect their children and themselves—fought against PG&E’s massive bank account and the politicians who just didn’t give a damn; they didn’t live there, so why worry.  Anything for a buck, right?  As I understand it the two units at Diablo (Devil’s) Canyon generate about a million dollars each every day of operation.

Thanks to the politicians, We The People get to pay for entombing these monster mistakes when they reach a point of ‘beyond serviceable life’ in the near future.  When that will be is difficult to say since PG&E applied for a permit to operate at 100+% for another 20 years!

I do not live in San Luis Obispo now.


This article is part of an ongoing investigation:
Nuclear Safety

Nuclear Safety

With the disaster in Japan, we're investigating questions about nuclear safety.

The Story So Far

Following a massive earthquake and tsunami in Japan, hydrogen explosions rocked three reactors at the Fukushima Daiichi nuclear power plant. Radioactive spent fuel stored in pools was also affected, especially at one reactor—the plant has a total of six—where multiple fires erupted. Evacuation orders were issued, potassium iodine tablets distributed, and plant employees used seawater and external electrical power to cool the stricken reactors, three of which had a partial core meltdown.

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