Japanese Nuclear Power Not the Same as US Nuclear Power


We all know that Japan suffered a huge earthquake and tsunami last week.  We’ve all heard the breathless talking heads screeching about a huge event in California, “the biggest event of your lifetime,” as one reporter put it.  This, of course, wasn’t the case.  Now, we’re hearing panic stricken reports of “exposed fuel rods” in Japan’s Fukijima and Daichi power plants.  There is evidence that the nuclear cores have been exposed to the air, since radioactive isotopes of Cesium (Cs) have been detected in the air.  This is bad, but bad mostly for people in Japan and the surrounding countries, not so much for us. 

I am a veteran of the US Navy’s nuclear power program and therefore know something about nuclear power.  I did a little digging, and according to the Japanese Nuclear power website, the two reactors mentioned above are old, commissioned in the late seventies, and are of a type that we don’t use in the US.  This type of reactor is inherently less safe than the types we use in the US.  Let me ‘splain. 

The Japanese reactors are boiling water reactors (BWR).  These reactors use carbon as a moderator (a material used to slow down neutrons created by fission that gives these neutrons a better a chance to interact with the fuel in the core and create other fissions, thus getting a more powerful nuclear chain reaction.) They also draw a steam bubble in the core, which increases the pressure in the plant and prevents boiling of the water elsewhere in the plant, like at the intake of coolant pumps.  Water is the coolant.  This water has been chemically treated to reduce corrosion of the parts in the plant, and to prevent the formation of scale on the the areas of the plant where a temperature difference occurs.  If you’ve ever had to change out a hot water heater, you know about scale.  It’s crusty crap that fouls the channels in the reactor where heat exchange takes place, and is a poor conductor of heat, therefore reducing the efficiency of heat transfer between the primary coolant and the secondary water (water in the plant that actually turns into steam to turn steam turbines and make electricity.)  The primary plant and secondary plants are isolated from each other. 

Now, in the US, we use pressurized water reactors (PWR).  In these reactors, water is used as the moderator, and a steam bubble is drawn in a pressurizer instead of in the core.  This keeps the core covered with water and increases the pressure in the plant.  The steam bubble pushes on the water in the pressurizer, and using Pascal’s principle, makes the plant pressure in the plant increase in proportion.  According to Pascal’s principle, pressure in one part of the plant is equal to all other points, and the steam bubble is used to control pressure.  Also, water is a much more efficient moderator than carbon because the molecules of water are much smaller and almost the same size as a neutron, so the collisions between the water molecules and neutrons slow them down much more than collisions between the carbon atoms will.  Imagine this:  you roll a pool ball at another pool ball.  If they collide, the energy from the first pool ball is almost all transferred to the second ball.  If you roll a pool ball at a bowling ball, the energy transfer from the pool ball to the bowling ball is much less.  Most of the energy from the collision remains in the pool ball.  This is the same type of energy transfer as occurs in a nuclear power reaction, if you imaging the first pool ball to be the neutron, and the second ball to be the moderator. 

Chernobyl was a BWR with a carbon moderator.  It’s design was nohwere near as safe as our designs are.  In contrast to US plants, the Chernobyl reactor had 65 miles of piping.  US plants typically have less than one mile.  I don’t know how many miles of piping Japan’s plant has. 

Keeping the core covered with water is the most important thing in a nuclear plant.  Since the Japanese plant has a steam bubble in the core, the potential for the core losing cooling is greater than in a PWR.  According to news reports, the Japanese plants scrammed (rapidly shut down) when they lost power to their cooling pumps.  The pumps not pumping water and the decay heat from the nuclear plant caused the steam bubble to expand, which therefore can expose the fuel rods to the steam bubble.  The fuel rods would overheat and begin to melt the materials used to make the fuel rods.  As long as the reactor vessel is contained in a containment building, the nuclear materials are kept in one place and therefore not released to the air.  The explosions we saw on the news was probably a steam explosion.  The nuclear materials in the steam are much less concentrated and less easily spread than if the core caught fire like it did in Russia.  The fire caused the nuclear materials to go high into the atmosphere and resettle all over Europe and the globe.  No fire in Japan.  Yet. 

Now, why would I tell you all of this?  Because the Democrat nuts in our country will certainly be pointing to the Japanese disaster to squelch nuclear plant development and construction of nuclear plants in the US.  It’s apples and oranges, people.  New US plants use natural circulation to cool the core.  Pumps would be a backup if the natural circulation failed, not the primary source of water flow.  This makes the plants less susceptible to problems caused by loss of coolant flow.  The Democrats, who want to install windmills everywhere, except in their own back yard, and depend on the sun to power the homes of Americans, except for their homes, will scream to shut down development and construction of all nuclear plants in the US.  That’s nuts.  We have enough nuclear material to power our country for thousands of years.  Windmills are great, when the wind is blowing, except that they are VERY noisy.  Solar panels are great, except that it takes a football field full of them to power the Energizer Bunny. 

Understand that nuclear power is the safest and cleanest form of power in the world right now, giving you the most bang for your buck.  One nuclear plant can power thousands of homes, creating no CO2, and creating one cubic yard of waste.  Coal plants create thousands of tons of waste and CO2 every day. 

So, don’t panic on this nuclear thing.  Not yet.  We don’t know what the Japanese are doing to cool their plants.  We don’t know what exploded on the news.  We hope that the Japanese did a better job building containment systems than they did operating their backup power systems.  It doesn’t make me feel too good knowing that the phone I have in my pocket had more R&D done on its components than the nuclear power industry did in Japan. 

This disaster should be about the people in Japan.  The loss of life is already ridiculous, and people have no food, water, or shelter.  This should be our focus. 

Pray for the people in Japan.  Send money.  Do whatever you can do to help.  They’ll need it.

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