Update (Added on March 18, 2011) There has been an incredible amount of coverage, fear mongering, and “worst case scenario” predicting. The Chairman of the US Nuclear Regulatory Commission risked offending one of America’s staunchest allies by recommending that all US citizens within 50 miles of the Fukushima Daiichi power plant evacuate. The recommendations coming from such highly placed appointees have led to additional panic, more difficulty in delivering supplies and more people packing into shelters. However, the predictions in this post have so far been born out. Even with the worst that nature can throw, and without perfection in response efforts, and without any off site power for a week, there is still no indication that anyone outside the fence of the plant will be exposed to any radiation doses high enough to cause a negative health effect – even over the long term.
There are some workers who are in areas where the dose rates are high enough to require judicious use of the principles of time, distance and shielding and they are having to be rotated to keep their total doses under control. Though this might be dated information, the highest recorded dose that I have seen for anyone was a single worker who received 10 REM in the very early stages of the response effort. I have searched carefully without finding any reports of any higher doses than that.
Here is a link worth reading – Early Radiation Data From Near Plant Eases Health Fears I intend to add more as time goes on.
BBC New (March 18, 2011) – Power hopes rise at Japan plant
End Update. Original post follows.
My thoughts and prayers are with all of the people who are struggling to deal with one of the worst natural disasters in recorded history. I have spent most of the past 24 hours trying to grasp the extent of the tragedy. It has been incredible to watch video replays that remind me of Hollywood movies that can best be enjoyed by employing the technique of “suspension of disbelief” that I learned while studying fiction story telling techniques. It is very difficult to imagine what it would be like to live in a comfortable, modern city one day and find it washed away within minutes. That wave could recede after having threatened your life, taken away all that you know and killed many people that you love.
There are fires at refineries, breaks in hydroelectric dams, explosions associated with natural gas systems, and massive quantities of contaminated land where the water overturned or damaged what were thousands of well designed containers full of hazardous materials. (For example, every automobile and truck that you see overturned by a wave contains a lead acid storage battery and tanks containing somewhere between 10-200 gallons of hydrocarbons. There is a 100% chance that some of that material has been released in an uncontrolled manner to the environment.)
The aftermath of this event will be a long and difficult clean up. Even in a well ordered and wealthy society like the one that exists in Japan, there will be places where physical evidence of the disaster will be detectable for decades. No one alive in Japan today will ever forget where they were on the afternoon of March 11, 2011. I can make those statements in such a positive manner because the record of recoveries from extensive natural disasters is as long as recorded human history; there is no reason to believe that this one will be substantially different.
What is incredible to me, however, is that there are many people who are focusing on the wrong thing and worrying about low consequence details of the damage that should only be a major concern for the people who are directly involved in accident response. I know it is hopelessly rational of me, but when faced with a confusing array of dangers, I have been trained to handle the ones most likely to hurt me or my loved ones first. Prioritization and triage are important tools in damage control; wasting resources on those aspects that are being well handled means you have less time and tools available to respond to the really pressing details.
There is at least one nuclear power plant that is apparently in danger of suffering long term damage. The operators are doing what they have been trained to do and working hard to keep their already shut down nuclear core covered with cooling water as the fission products decay away. Because they are in a place where all basic services have been cut off, getting electricity to their cooling water supply pumps is a serious challenge. As hospitals in Louisiana found out after Katrina, emergency diesel generators only supply power if you also manage to continue to deliver a sufficient supply of fuel to keep them running.
The almost certain scenario at all of the nuclear plants in Japan is that all of the hazardous material will be contained within the carefully engineered and constructed reactor pressure vessels and the surrounding containment building that were installed before the plants were ever started. During the course of events, there will almost certainly be a need for at least some of the the plant operators to carefully release non-condensible gases from their containment building. Some of those gases will be chemically inert “noble” gases that contain radioactive isotopes. No one will receive a high enough dose of radiation to cause any negative health effects.
I have no first hand knowledge of the specifics at the Fukushima Daiichi nuclear plant, or at the Fukushima Daini plant or any of the other plants that might experience similar challenges during the next few days. However, I spent a decade or so being trained and serving as an operator and department head for a nuclear power plant cooled by ordinary water (what we call “light water”). That deeply engrained experience helps me to have a pretty fair idea what must be going on at standard issue reactor plants constructed to international standards in the case where supplying even emergency electrical power is nearly impossible.
I have also studied the reports of the post accident material autopsies conducted at Three Mile Island Unit II in enough detail to be reasonably confident of my understanding of what might happen if the struggling operators are unable to power their cooling water pumps for an extended period of time.
Because standard water cooled nuclear reactors need to be supplied with more water as fission products decay and they cool down, their fuel can be damaged if the water is not delivered. Without water, even the ceramic fuel pellets that can withstand extremely high temperatures can melt. However, the fact that even moderately well trained nuclear specialists may not fully grasp is that the melted fuel is only generating enough heat to melt itself; it is not generating sufficient heat to melt through the thick steel pressure vessel where it resides.
At TMI, the widely predicted and discussed “China Syndrome” did not happen, even though 20-30% of the core melted and slumped to the bottom of the pressure vessel. That melted corium froze again once it contacted the thick metal walls – the maximum measured penetration was just 5/8ths of an inch. Anyone who has ever watched as welder employs a torch to cut through a thick steel wall will understand just how much concentrated power it takes to melt several inches of steel. Avoiding the China Syndrome was not a matter of luck
– the scenario is imaginary and only works in fiction. Physics and material science make it impossible.
The plant’s containment dome will be contaminated as a result of being the reception location for the steam that boils away while the operators are trying to restore cooling flow. That water will have contacted the core and will contain some of the core material as the cladding gets overheated and damaged.
Radiation levels inside the containment will be many times higher than usual, but that is okay because no one needs routine access inside containment buildings and no humans will be over exposed. The containment walls, reactor coolant piping, and other equipment inside the containment building will condense and capture much of the radioactive materials that are entrained in the water. Other than those vented noble gases mentioned above, essentially nothing will be released to the environment.
If you do not believe me, please read the compact, two page article that was published in the 20 September 2002 issue of Science Magazine titled Nuclear Power Plants and Their Fuel as Terrorist Targets. That article, jointly written by 11 of the most eminent nuclear specialists in the United States clearly lays out the possible consequences of the worst possible damage that can occur at a light water reactor with a containment dome licensed to “Western” standards.
Though technically incompetent professional fear mongers like Harvey Wasserman and Congressman Edward Markey will do their best to use the Japanese tsunami as another arrow in their quiver of antinuclear propaganda, the aftermath will show that all of the hype and fear will signify nothing. There may well be some damage at the plant, but the damage will be contained as a result of the defense in depth strategy that is enabled in nuclear power plants because of the exceedingly compact nature of the fuel material. Since nuclear fuel is so compact and so inexpensive, we can afford to surround it with several protective layers and still produce power plants whose output is affordable and normally very reliable.
From a nuclear power plant point of view only, the worst long term effect of the earthquake will be the fact that there might be a dozen or so plants that remain shutdown for an extended period of time. Because there is so much fear associated with radioactive materials, the standards set for inspection before restarting the plants is quite high. Based on the experience of the less consequential earthquake that affected the Kashiwazaki-Kariwa nuclear station on 16 July 2007 it may take a couple of years before plants that were shaken by the 11 March 2011 quake are allowed to start up and begin supplying customer needs. At Kashiwazaki-Kariwa only three of seven plants had been started up by June 2010, three years after an earthquake did not substantially damage them. It takes a long time to inspect the large quantities of piping and equipment associated with large nuclear power plants to the exacting standards applied.
As the Japanese economy recovers from the quake and power customers get their supplying wires restored, the demand for power will be met by importing more fuel oil, importing more Liquified Natural Gas and importing more coal.
Those additional demands on an already stressed fossil fuel market will cause world wide prices to be even higher than they would have been. There are already investors who are working hard to figure out how to play that very predictable consequence of the accident for their own gain. If you do not believe that statement, I recommend reading Bloomberg’s March 11, 2011 article titled Japan’s Post-Quake Energy Import Surge Will Boost Reliance.
Only after putting you through the experience of reading the above do I feel good about sharing a completely different and breathless kind of report from a journalist who makes a number of technically incorrect statements in an attempt to tell a story that he just does not understand, but which he and his producers think will attract viewers so they will watch the commercials that keep his employer in the black. Watch the below at your own risk – it is designed to scare you and to provide the same kind of entertainment that some pay for when they watch badly scripted disaster movies.
Update: (March 12, 2011 11:20 am EST) There have been reports of a hydrogen explosion and walls crumbling to expose a steel frame at what is described as an outbuilding at the Fukushima Daiichi power station. Those reports triggered my memory of a hydrogen explosion that occurred at the Tampa Electric Company Gannon coal fired power plant on April 8, 1999.
In the Gannon Station case, the hydrogen for the explosion came from the cooling system for the very large electrical generator. Maintenance workers apparently did not ensure that the system was properly purged before opening it for maintenance.
My guess is that a similar generator cooling system was in use at Fukushima Daiichi. Considering the devastation that has occurred as a result of the earthquake and the tsunami, it would not be terribly surprising if the electrical generator cooling system developed some hydrogen leaks. From what I have read about the actions taken to cool down the nuclear fuel inside the reactor, which is inside a robust containment building, not a steel frame building, I am guessing that the explosion had nothing to do with the heat source that normally supplies the the steam to turn the turbines that turn that electrical generator.
I am quite willing to eat crow if it turns out I am wrong.
Update: (March 18 7:20 PM) I did have to eat some crow on this analysis. The exact source of the H2 explosion is not known, but it was not in the turbine building and not associated with the electrical generator. End Update:
Brave New Climate discussion thread Japanese nuclear reactors and the 11 March 2011 earthquake
World Nuclear News (March 12, 2011) Battle to stabilise earthquake reactors (This article is being updated as events unfold.)