First, I would like to express my concern for all those affected by the earthquake. Our thoughts and prayers go out to the people of Japan and the workers at the Fukushima Daiichi plant and their families.
In response to your specific question ... eventually the heat remaining in the fuel will reach a stage that will enable it to be removed or permanently encased. That likely won't for a number of years. Until then, the fuel will have to be cooled with water.
How much radiation can destroy our civilization? How can we prevent the radiation effects?
Radiation exists in nature, and we are all exposed to it every day. Scientists know that certain levels of radiation are not harmful. However, higher levels of radiation over short periods of time can be very harmful.
Indications lead us to believe that the fuel in Units 1, 2 and 3 at the Fukushima Daiichi plant has been damaged. We do not know the exact extent of that damage at this point.
First, the cause of the fire reported at Unit 4 is not linked to the fuel in the pool. The fire was associated with equipment in the vicinity of the fuel pool.
Tokyo Electric Power is working to engineer a system to add water to the fuel pool.
I suggest the word "meltdown" is too strong. "Damaged" is a more accurate word if the fuel in the pool has been affected.
All we know at this point is that the Onagawa plant has been shut down safely and does not appear to have been severely affected by the tsunami or the earthquake.
The workers at the Fukushima plant have attempted to manage and mitigate the effects of an extreme natural disaster that has completely destroyed the towns and countryside surrounding the plant and their homes. Yet they continue to work in highly adverse conditions. The actions taken by Tokyo Electric Power and the government of Japan to evacuate 200,000 people in an orderly manner -- with devastation of transporation and communications systems -- is extremely commendable.
No doubt when the situation has stablilized, Japanese and international nuclear experts will review the actions taken and incorporate lessons learned from this event.
Dan, Nadia and Taybi:
At this stage, we don't see any impact on the West Coast or Hawaii from the earthquake and the effects on the Fukushima plant.
You may recall that the worst commercial nuclear plant accident in the United States, the Three Mile Island accident in 1979, involved a partial melting of the reactor core. There were no fatalities or injuries as a result of the accident, though it caused considerable stress.
The heat from nuclear reaction takes a long time to dissipate. As a result, it takes time to return the plant to a stable condition. Once in a stable condition, action will be taken to decommission those facilities where fuel damage has occurred. This will take many years.
We share your concerns. Unfortunately, we are unable to provide accurate projections or advice on your travel plans.
To clarify ... the safety sytems worked properly at the Fukushima plant following the earthquake until the tsunami hit the plant. The tsunami destroyed the electrical power systems that supported the safety systems. The alternative safety systems continued to work until the thermal conditions caused those alternative safety systems to fail. The extensive devastation within and external to the plant caused by the tsunami hampered restoration efforts.
In the United States, the power companies are required by law to purchase liability insurance (via the Price-Anderson Act), which is pooled should an accident occur and whose exceeds $10-12 billion.
Over the past 20 years the safety at nuclear power plants in the U.S. has been increased at least five-fold.
US. nuclearpower plants along with those of other nations have developed procedures and protocols for dealing with severe accidents of the type seen in Japan.
At this stage it is unclear whether the containment structure has been damaged or the extent of any damage. Circumstantial evidence appears to indicate that the containment structure may have been damaged, yet I have not seen confirmation of this by the Japanese governement or Tokyo Electric Power.
From reports I understand that once they began to lose injection capability from the alternate safety systems they began to inject boron.
Unfortunately, I have to close the chat room now since I have another interview scheduled in 10 minutes. If I did not get to your question I suggest you send your question to www.nei.org.
Thank you for your patience and time this afternoon or where ever you are located.
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