By Phred Dvorak
Just how dangerous is the situation at Japan’s crippled Fukushima Daiichi nuclear plant? Very, according to U.S. Senator Ron Wyden, a senior member of the Senate’s energy committee who toured the plant earlier this month.
- Associated Press
- The Unit 4 reactor building of the Fukushima Daiichi nuclear power plant in November 2011.
Another big earthquake or tsunami could send Fukushima Daiichi’s fragile reactor buildings tumbling down, resulting in “an even greater release of radiation than the initial accident,” Mr. Wyden warned in a Monday letter to Japanese Ambassador to the U.S. Ichiro Fujisaki.
In particular, Japan isn’t moving fast enough to remove dangerous nuclear-fuel rods from the reactors, and the U.S. should offer its help to speed things along, Mr. Wyden urged, in letters to Ambassador Fujisaki, as well as U.S. Energy Secretary Steven Chu, Secretary of State Hillary Clinton and Nuclear Regulatory Commission Chairman Gregory Jaczko.
Yoshikazu Nagai, a spokesman for Fukushima Daiichi operator Tokyo Electric Power Co. said the company couldn’t comment on the letter, and that all it can do is “proceed steadily with the (cleanup) roadmap.” Japan’s Foreign Ministry declined to comment.
Mr. Wyden’s warning touches on what some experts think is the biggest problem at the Fukushima plant: another earthquake or tsunami that exposes the least protected of its nuclear fuel to outside air.
Fukushima Daiichi suffered meltdowns at three of its reactors last year after the March 11 earthquake and tsunami knocked out power in the area. Much of the nuclear fuel in those three reactors is thought to be in a melted lump at the bottom of the vessels that surround the core. That’s bad, but at least the vessels shield the outside world from the radioactive fuel.
But Fukushima Daiichi’s Unit 4 reactor was shut down for maintenance when last year’s accident took place, meaning the nuclear fuel rods were outside those protective vessels and sitting in a pool of water, high up in the reactor building, where they were being stored. The water in that “spent fuel pool” keeps the rods cool and insulates them from the outside. But if the pool should spring a leak, or another earthquake bring the pool crashing down, all that fuel would be exposed to the outside air, letting them heat up and release massive amounts of radiation. Other reactors have spent-fuel pools too, but they contain less fuel.
Tepco says an analysis it conducted on the Unit 4 pool showed the building didn’t need reinforcing, but it went ahead and reinforced the structure anyway, increasing its safety margin by 20%. Tepco says it’s working to remove the fuel rods as fast as it can. If all goes according to its timetable, the utility could start taking the rods out in 2014.
Mr. Wyden points out, though, that the schedule allows up to ten years to get all the spent fuel in all the Fukushima reactor pools out — something he says is too risky.
“This schedule carries extraordinary and continuing risk if further severe seismic events were to occur,” he wrote in his letter to Ambassador Fujisaki. “The true earthquake risk for the site was seriously underestimated and remains unresolved.”
As an engineer with practical experience with spent fuel most concerns I hear are raised by those with no experience. The potential hazards are know. That is why spent fuel pools are very sturdy structures that have never been damaged by an earthquake. Spent fuel pools have thick stainless steel liners which do not because of earthquakes.
No spent fuel damage occurred at any nuke any where.
Nuclear plants have experienced many earthquakes. Building that have already survived earthquake are proven suggesting they are going to crumble all the sudden does not make much sense.
Loss of cooling or make up water for boil off is another thing that I am not concerned about. The first thing to consider is the spent fuel has now been out of the reactor more than a year. The time to heat up and boil off 60 feet of water is many weeks. It is credible that the next quake could temporarily interrupt cooling but not for weeks.
I think the reason it will take till 2014 is that they have to build an entire building around #4 that is not at all supported by #4. They have to build an upside down L shaped building in order to remove the fuel rods. WHen they remove the rods, I don’t think they can be exposed to the air, hence the building. GOing to have to be a marvel of engineering to even do this in a safe manner. Unfortunately that takes time. It’s really a race against time, and this is a long way from being over.
Also if #4 does go bad and no one can get close, good luck on maintaining the other 3.
Thank you for this coverage. It takes courage to speak the truth. The one point in the article I disagree with is the statement that the melted fuel at the bottom of the containment vessels is protected from the environment. Not true: there has been and continues to be massive amounts of radiation being leaked into the environment by the thousands of tons of water being cycled through the vessels in a attempt to cool the fuel. Much of this water has been released or has leaked.
Echoing the previous commentator, it is important to stress that, at this point, the larger issue is existence of so-called spent fuel currently spread across the planet and accumulating every day, all of it at risk of melt-down….
Pool #4 contains several times more Cesium-137 than was released by Chernobyl. We know that it is particularly dangerous, because it contains about 1200 rods that were recently removed from reactor #4. This means the fuel is extremely hot, both thermally and radioactively, and will surely melt and probably catch fire and burn if the pool is breached through the collapse of the building housing it.
A loss of coolant in the spent fuel pool — whether by leakage, spillage, or boiling off of the cooling water — will lead to intense gamma radiation that would prevent human access for hundreds of meters in all directions around the spent fuel pool, making it very difficult to take corrective actions.
Since the common pool, which holds 6200 spent fuel rods, is located 50 meters from fuel pool #4, These rods are considered “cool”, which means that a loss of ability to cool them would mean that the water in their pool would not boil off for a matter of probably weeks. However, assuming that the common pool becomes inaccessible because of gamma radiation given off by a breached pool #4, then it seems quite possible that the 6200 rods would at some point become exposed to air and then also begin melting. These 6200 rods contain tens of times the Cesium-137 that was released by Chernobyl. As Arnie Gundersen said at the outset of Fukushima, this disaster could become “Chernobyl on steroids”.
Thank you Wall Street Journal. I was hoping that the US Senator’s letter would make the mainstream media pay attention.
Now, what’s missing here is the really scary part. If the pool springs a leak or worse, collapses, within hours of being exposed to the air, the rods start to burn. What that means is no one can get close to it or the plant itself. Also, possibly they didn’t point this out to the Senator, a mere 50 meters from #4 is the BIG spent fuel pond that holds 6300+ rods! They will lose everything, all the reactors, all the cooling, etc. if #4 goes.
The Senator is absolutely correct – they need help but it looks like they won’t even comment on the letter, never mind accept help. The entire world needs to put pressure on Japan to get this done. Note that the few spent fuel rods that were put into dry storage came out undamaged from the tsunami.
Something else too – that pond holds LIVE fuel as it was undergoing maintenance at the time.
At this point the spent fuel is a huge concern and I’d feel a whole lot more confident if my Canadian government; the US; the Germans, etc. were all in there helping. We did build the Canada Arm for the space station!
Please don’t stop reporting. Maybe you could get the other mainstream media to write/cover this as well because without significant attention and pressure it’s going to be more of the same lack of transparency by the Japanese government. A few minutes on Google and the situation at Fukushima becomes all too clear. We are not be told what’s going on and if the information we are getting isn’t horrifying enough, what aren’t they telling us???
Again, thanks for your courage and please do continue to follow this story because the implications are very clear and very real – the human race’s survival depends on these guys doing a good and very careful job. The same ones that didn’t insulate pipes holding radioactive water in the dead of winter! Yes, I have lots of confidence!!!