Roadwolf's portal for his random thoughts and ponderings

Understanding the Risks of Fukushima

I am quite surprised that so many people seem to be just shrugging off the current situation at Fukushima.  Many major North American news networks are not reporting the issue, or if they are, they are often understating the issue.  How do I know that this event is being understated?  Well I shall explain here in the most basic terms I can think of.

Nuclear Plants often have multipul Reactors.  Each reactor produces heat, which boils water, which then turns into steam which is then used to spin a turbine.  The reactors use a process called Nuclear Fission to produce this heat.  This process creates a lot of radioactivity.  All of this is enclosed within the core which keeps most of the radioactivity inside, and prevents any from leaking out.  This core is contained within a containment enclosure inside the reactor building.

Distilled Water or other cooling liquids are pumped through the reactor core to cool it constantly.  For if the Uranium fuel inside the core gets too hot, it can melt, and fall to the bottom of the core, where it will easily melt through the core, and become very difficult to contain.  It can get so hot that it will turn concrete molten, and will easily find its way outside the plant.

Most nuclear plants use control rods made of carbon which when lowered between the uranium fuel rods will stem the reaction.  But they are unable to stop the reaction completely.

Nuclear power plants there fore must always be supplied power, so that they can operate cooling pumps which will circulate coolant into the reactors to cool them off.  Even if the reactors are shut down.

If the cooling system fails, and the backup system fails, then the core will begin to get very hot.  Chemical reactions inside the core and containment building begin and the water is often boiled off.  Excess hydrogen is often produced which causes a serious explosion - which we have seen at Chernobyl and Fukushima.

Such an explosion in itself is very serious, minus the fact that it is radioactive and part of a bigger problem.  And in both cases workers near or inside the plant died in the explosion.

At this point, there is very little that can be done to avert a total nuclear melt down.  One can park a few fire trucks beside the plant and pour/dump in water, lead, sand and boron, and hope that the reactions subsides with enough boron added.

However once the fuel begins to heat up, and melt - a critical situation is currently underway.  If even a single uranium fuel pellet, which is about the size of a marble, melts and drips to the bottom of the containment core, it could eat its way through the core, and cause a leak of radioactive cooling fluids, which will further cause the core to heat up, and more fuel to melt and drop down.

In otherwords,  loss of cooling systems + time = extreme pressure buildups, extreme heat, and makes it even more difficult to control over time.  Eventually concluding in a complete meltdown.

That being said, in a perfect world, none of this would happen.  GE Designed Fukushimas reactors to be extremely safe.  This event should not of happened if you base your theories on textbook perfect operating condition scenarios.

But right now, Japan is not a perfect world.  In fact it is probably the worst possible situation.  Wide spread utility failures with Gas, Water, Sewer and Power lines all effected.  Telecommunication issues as well.  Infrastructure is severly damaged, and many vehicles and backup generators which were in the wake of the tsunami will no longer operate because of water logged engines - assuming they wern't damaged in another manner.  Fuel is running low, and in the case of Fukushima, many of its employees have been injured, killed, or exposed to radiation while working to try to fix the problems.  Plus the problems of having to search for survivors of the tsunami, and deal with non power plant related emergencies...   The government / emergency services / army is stretched thin.

Add that with the fact that so far it looks like 4 power plants have cooling system troubles.  Each plant having at least 2 reactors.  And each reactor being as big, if not bigger then the reactor involved at Chernobyl.  Dealing with a single reactor in perfect conditions would likely be a national emergency situation.  So having 4 power plants right now in trouble, is very bad considering that the resources to stabilize a single reactor were not even available.

Yesterdays report from Fukushima indicated that exposure rates outside the plant were at about 620 millirems per hour.  That is still fairly low, seeing as at Chernobyl, readings outside the plant were apparently 10,000 millirems per hour shortly after the explosion.  A fatal dose is about 500 R over 5 hours, or 100,000 millirems per hour.

The annual dose for workers in the nuclear industry is 5,000 millirems.  Which equates to 0.570 millirems per hour.  So yes, something is happening there that is not normal, and not contained.  0.570 millirems per hour is about equal to having a chest x-ray preformed on you every hour.

Will we feel it in the USA / Canada / Europe?  Yes, but the effects will be minimal compared to local contamination.  Airborne fallout can easily reach the western coast, and we may experience radiation that is maybe 2 to 10 times higher then normal.  Will that kill us?  No, it won't,  it likely wont even cause any harm.  But the possibility does exist that it will increase our chances of getting cancer.  (Note: I lowered my estimation from 5 to 20 to 2 to 10 based on the reports that the other power plants have regained cooling and are now safe, and that things seem to be coming under control).

The fallout from Chernobyl was 100 times less severe then the combined fallout from the atomic bomb testing done from the 50's through the 1960's.  But considering that there were 1000 atomic bombs dropped in that time frame worldwide...   That still makes the fallout from Chernobyl worse then a single atomic bomb.  In fact it is about 10 times the fallout of a single atomic bomb.  The current crisis in Japan is looking to be much worse then Chernobyl if they can not restore cooling to all of the effected reactors and reactors continue to explode, or even worse if they catch fire!  Therefore if you consider the nuclear power issues in Japan right now as a single event - this event might create the worse fallout seen to date.

That being said, these reactors do tend to resist fire.  So, the chances that high amounts of radioactive material will be lifted into the air, is less likely if there is no fire.  Plus it is also apparently raining in Japan right now, which will cause much of the airborne particles to fall locally.

Living in Buffalo / Niagara Falls I am used to radioactivity.  The Manhatten project dumped a lot of radioactive waste in this area.  Buffalo Street in Niagara Falls, NY is said to have 50 times normal background radiation if you are standing on the sidewalk.  Apparently the pavement contained radioactive waste.  In Lewiston, NY there is a site which contains areas which are rumored to be 1,000 times normal background radiation.

So no, it will not kill us.  But... Prepare for the worst, hope for the best.

I personally purchased some Potassium Iodine pills...  Their good to have around, and just in case things get bad, I will have them.  I do not intend to spread panic.  In fact in the process of writing and doing the research for this post, I myself was relieved at how little fallout we may get.  Up until today however it seems that my guesses about what was going to happen next were fairly accurate, when they were often completely opposite officials statements.  I am happy to hear that things appear to becoming under control, so likely this was all a non issue at this point.

I am still a proponent of nuclear power.  I hope that this doesn't quench support for new nuclear power projects.  A safe way to build a nuclear power plant is to build a coal (or alternative fuel) power plant right beside it, and allow the coal plant to hook up directly to the nuclear plant to provide cooling and/or power.  And uh,  don't build power plants in the middle of population centers or near major fault lines.

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