Our country needs to get off of the oil economy. We are paying more and more for a finite resource that we have no control over.
I will try to make a case for a newer nuclear technology called Pebble bed modular reactors or PBMR
Disclaimer: I am not an expert and the information in this diary was found searching PBMR on google.
I want to explore some of the real objections to nuclear power and try to get beyond the irrational fears that have kept us from moving forward with this technology.
By moving forward to a different type of reactor we can address most of the objections and concentrate on the benefits of nuclear power.
This technology is in my view to be used as a stopgap measure to make the transition from the oil economy to totally green renewable energy less painful and to provide a cushion so our total economy doesn't crash.
One of the biggest advantages is that it is existing technology so we don't have to invent something for this to start producing results.
Currently in the US we are using light water reactors to produce about 20% of our electric output and we also burn coal for about 50% of our electricity.
Light water reactors use water as the cooling agent and the transfer agent between the core and the steam turbines that generate our electricity.
Pebble Bed Modular Reactors are a different kind of reactor called High Temperature Gas Reactors or HTGR
They use helium as the cooling medium and this gas goes directly to the turbines to produce electricity. They can do this because the helium doesn't become radioactive while it is in the core. This makes the reactor simpler,safer, cheaper and more efficient.
The PBMR starts with a different fuel configuration using enriched uranium dioxide coated with silicon carbide and pyrolitic carbon. The particles are encased in graphite to form a fuel sphere or pebble about the size of a tennis ball.
This fuel configuration has the advantage of having 3 layers of protection for the nuclear material making the power density about 1/30 of a fuel rod. This power density difference and the way the nuclear reaction can only work in a small temperature range makes the design meltdown proof.
Now I would like to address the objections to nuclear power and to show why the PBMR eliminates most of them.
Here are some of the top objections that are associated with existing nuclear power.
Power plants have had accidents in the past.
The reactor is cooled by an inert, fireproof gas, so it cannot have a steam explosion as a light-water reactor can. The coolant has no phase transitions—it starts as a gas and remains a gas.
The moderator is solid carbon. It does not act as a coolant, move, or have phase transitions (i.e. between liquid and gas) as the light water in conventional reactors does.
A pebble-bed reactor thus can have all of its supporting machinery fail, and the reactor will not crack, melt, explode or spew hazardous wastes. It simply goes up to a designed "idle" temperature, and stays there. In that state, the reactor vessel radiates heat, but the vessel and fuel spheres remain intact and undamaged. The machinery can be repaired or the fuel can be removed.
The fuel and the waste could make dirty bombs.
Because the fuel is encased in graphite and carbon the concentration of nuclear material is smaller and the pebbles are stronger than diamond and strong even at 2000 degrees C so would be very hard to use as dirty bomb material.
Nuclear power plants are readily identified from the air, so they are terrorist targets.
The foot print of the PBMR is small and doesn't include the great big cooling towers that the light water reactors do so they could be camoflaged in an industrial park just about anywhere. 10 reactors chained together take up as much room as 3 football fields with most of the construction underground as they are built on bedrock.
There is no safe place to store the waste.
The design of the of PBMR fuel makes it easy to store the spent fuel, because the silicon carbide coating on the fuel spheres will keep the radioactive decay particles isolated for approximately a million years, which is longer that the activity even of plutonium. The pebbles circulate thru the container and regularly come out the bottom allowing them to be tested for reactivity. They are only taken out if they are spent.
The spent fuel stays radioactive for extremely long periods of time.
This will continue to be a problem but the configuration of fuel for the PBMR would allow us to take nuclear waste and reuse some of it reducing the amount of waste. Because the fuel is less dense and spent before it is taken out of use it can be stored on site in lead lined bins. This is built into the design of the facility and storage is provided for a 40 year plant lifespan.
because we have used nuclear bombs everyone is aware of the devastation they can cause.
A pebble-bed reactor thus can have all of its supporting machinery fail, and the reactor will not crack, melt, explode or spew hazardous wastes.
we were subjected to a lot of different media that bombarded us with the fear of nuclear bombs from the Russians.
many movies used the theme of radiation as a mutating force, again playing on the fear angle.
Irrational fear planted by the traditional media, Imagine that
FEAR, NOT!
By changing to a different type of reactor we can eliminate most of the objections and move forward to the new energy economy
The benefits of nuclear energy using the new type of reactor called Pebble bed modular reactors or PBMR start with.
The availability and the quantity of fuel here in the U.S.
The U.S. has the 4th largest reserve of uranium in the world with allies Canada and Australia having more.
The PBMR doesn't need high grade fuel. It can use thorium and has also been tested with reconditioned fuel from existing nuclear plants and decomissioned nuclear warheads.
No green house gas emissions.
1 kilogram of uranium has as much power potential as 4500 tons of coal.
Can be built anywhere.
The actual blueprint of the reactor could be approved by the NRC and distributed to any company that wants to build a plant. by standardizing the design the construction could be modularized and any plant could be expanded as the need arose. This would also simplify the inspection process. With only one design these plants could be mass produced.
Is inherently safe.
The traditional light water plant has many redundant systems and an active prevention model. PBMR uses a passive prevention model because the temprature of the core can't get critical and even at it's hottest the fuel pebbles are stable.
The byproduct of heat can be used to create hydrogen.
By creating hydrogen the plant can run constantly at a higher efficiency because if the grid doesn't need the electricity you can produce hydrogen which also allows us to replace gasoline as the prefered fuel for our cars.
The byproduct of heat can be used by industry and government to heat buildings or run steam dryers.
The technology exists to use cogenerated steam to heat and cool.
They are relatively cheap to build ($300 million for 200 Mw).
Traditional light water reactors had to provide so many layers of redundant protection their costs skyrocketed.
PBMR using a single design could be mass produced saving approval time and construction costs, plus they are simpler to operate.
The bottom line is that nuclear power is a stop gap technology. But if we get beyond our fear and use the technology available we should be able to transition to renewables without crashing our economy.
Thank you for your time and I welcome all comments.