What's in a Pebble?

I talked a little last week about an old idea known as the "Pebble Bed Reactor". This week I would like to go into more detail as to what these pebbles are.

A pebble bed reactor is a type of VHTR or Very High Temperature Reactor that is cooled with gas and uses spherical (pebble) shaped fuel pieces which possess a layer of graphite in order to control the reaction rate. It  is these pebbles that are what distinguish the pebble bed reactor from all other nuclear reactor types on the market. Each small pebble contains thousands of tiny fuel particles. Below is a schematic of a typical fuel pebble and a picture of real one.

The graphite shell acts as a "neutron moderator" and thus controls the reaction rate.
In a PBR, thousands of these fuel pebbles would be brought together to form the reactor's core. The pebbles must be cooled and thus normally helium gas is used to do so. Finally, for safety reasons the pebbles are also coated with a layer of silicon carbide in an attempt to fireproof the pebbles.

It is quite amazing...just by placing the pebbles in a specific and calculated geometry, criticality can be reached and thus we have a working nuclear reactor.

China's Upcoming Pebble-Bed Reactor

In the wake of what has happened in Japan it is great relief for me to see that news agencies have once again started talking about nuclear technology versus nuclear disasters. For example, last Thursday the Times featured an article about a special kind of nuclear reactor that is currently being built in China, called a Pebble-bed reactor. This specific type of reactor is an HTGR or high-temperature gas cooled reactor meaning that instead of being cooled by water  (like the majority of nuclear reactors out there are) this reactor is cooled with non-explosive helium gas. This means that if electricity were lost to the reactor (thus no water could be pumped for cooling), it could still be cooled by the gas. Great news right!

The Times talks about how instead of using "conventional fuel rod assemblies of the sort leaking radiation in Japan, each packed with nearly 400 pounds of uranium" the Chinese reactors will instead use "hundreds of thousands of billiard-ball-size fuel elements, each cloaked in its own protective layer of graphite"

Turns out that the "graphite coating" controls the speed of the nuclear reactions. It is truly awesome science. The Times even states that if the plant were to shut down due to an emergency, then the nuclear reactions would come to a stop all on their own (such smart little billiard balls of fuel).

So apparently this is old news...and this already started in Germany in the 1960s (but came to a halt and never preceded). Turns out that in the USA right now the government is working with Westinghouse and General Atomics to research similar ideas.

Sounds like a great idea to me. I hope to bring you more on the story...stay tuned!

Media Portrayal of Fukushima Part 2 - Faster than a Speeding Bullet

I recently wrote a short post on how I felt about the media discussing the Fukushima Nuclear Plant. I would like to continue on another note but it will be brief. You see, I use GoogleNews to get my updates on the nuclear energy world...I keep it simple by typing "nuclear energy" into the news search and reading usually the first ten stories. Before Japan's latest earthquake and tsunami, results were generally positive or neutral to the nuclear movement (don't think I don't read the negative ones though...they are usually the most interesting). Following the disaster however, things took a big turn. For example, if you were to type in "nuclear energy" into GoogleNews today the first few stories that pop up are:

1. Nuclear Energy Isn't Needed
2. Catholic Expert: Japan disaster raises ethical questions about energy 
                       ---(seriously, I know right?)
3. Why nuclear and fossil fuels are disasters waiting to happen.

I'm not trying to discuss the obvious I know that it's clear to everyone that this is an opportune time for those who stand against nuclear to try to get the public to hear what they have to say, it just amazes me at how fast the media can change uh how should I put this...the way the media changes "how things seem". If I was someone who had no idea about the pros and cons of nuclear energy and looked it up a month ago...boy it would just about seem that everyone was on the nuclear bandwagon and so should I. Look it up now...are there seriously governments that allow such things to be built in their country?

It's sad but it's the way things are and the way they've always been.

Sorry for the rant.

“All media exist to invest our lives with artificial perceptions and arbitrary values” Marshall McLuhan

Fukushima Nuclear Power Plant-The Type of "Science" the Media Loves

Although it is my Spring Break and I am trying to enjoy it, it is hard to enjoy anything when we turn on the television and we see that Japan has been devastated. I'm sure we all, at some point, have seen the television and heard of the dire situation in Japan. And ever since the explosion at Fukushima I have been drowning in comments from friends, fellow students, and even my own family members about the future of nuclear power after this incident (my parents called earlier today and my father told me he doesn't think grad school in nuclear engineering is still a good idea).

The Fukushima nuclear plant situation is a great example for my Communicating in Science class...it shows exactly how science and technology are at the mercy of the media. When people ask me questions about the situation and how "nuclear power isn't looking so safe" they are armed with "facts" that they picked up from CNN or Fox when really they should be reading from science publications that are written by people who are respected in the field.

Therefore, I will provide some links that will allow the public to read up on the real facts concerning the nuclear plant in Japan. One link is to a page generated by Dr. Jeff King (prof. at the Colorado School of Mines) with links to other sites that give information on the topic from nuclear professionals. The second link is a facebook page also created by Jeff King that has updates on the situation.

A powerful paragraph that I found from Dr. King's page:
"6:42 PM MST 3/12, If you stop to think about it, as far as engineering disasters go, this one is so far low on the scale. On 9/11, a fully-fueled passenger jet was piloted into each of the World Trade Center towers. 2606 people died when engineering failures allowed the support beams to buckle in the resulting fires, causing the buildings to collapse. So far, Fukushima Daiichi Unit 1 has been hit with the fourth largest earthquake in recorded history, slammed by a massive tsunami, and had the top ripped off of it by a hydrogen explosion. Total death toll at/from the reactors so far? One - a crane operator who was apparently killed in the initial earthquake. (And he was actually at Fukushima Daini - a different facilty.) "

I urge you to arm yourselves with real facts on the situation, there is nothing more dangerous than knowing "a little" on the subject. And "a little" is exactly what you will get from the television. Not to be corny and predictable but an old Japanese proverb says it best, "If you understand everything, you must be misinformed."

***My heart goes out to all of those who have been affected by the earthquake.***

Tennessee Plans For Change

If you have been keeping up with this blog you would have read my last post in which I described three US states that were pushing forward with legislation in order to have more nuclear energy in their future. Well there is good news...looks like we can add one to that list...and perhaps to the very top.

A Tennessee power company (TVA, Tennessee Valley Authority) has just released a 20 year plan detailing its interest in renewable resources to possibly lose its dependence on coal. The TVA states that it needs to meet the constantly rising energy demands of its people while also providing cleaner energy.

TVA is interested like everyone else in incorporating renewable resources such as solar and wind into its energy production budget. But shockingly TVA also announced that in 20 years it hopes that nuclear energy will represent more than half of its energy output. That's amazing and I'm glad to see that at least some states in the USA are awake and are finally realizing what is going on around them.

A powerful quote that was taken from one of the developers of the energy plan, Gary Brinkworth:

“While there may be individual components that are expensive, when you bring those all together, clearly adding those renewables gives us a stronger plan, a lower cost plan.”

Three States Making a Move for It

I just read from another blog that three states that are not currently associated with nuclear energy have jumped on the bandwagon. According to The Energy Collective, the states of Missouri, Iowa, and Indiana have recently been making some political moves that may pave the way for nuclear reactors (Iowa does currently have one reactor). From passing new laws that make funding a lot easier to come by for Missouri and Indeana and as for Iowa the possibility of miniature reactors.

One of the big topics recently has been on states that are passing legislation to allow utility companies to add a small fee to energy bills in order to pay for nuclear reactors to be constructed. I could see this making a lot of people angry...our energy bills are high enough already right? Well lawmakers are looking at the data...a recent poll suggested that more than 70% of the USA population support nuclear energy. I guess they figure if we all want it...we won't mind paying for it. If you think about it in the end it will make energy bills lower in the future..if not for you at least for your children. So I say "yay" to this!

Interview: Dr. Ed Cecil, Physics Dept, CSM...and One Really Cool Guy

I have had the privilege, during my four years at the Colorado School of Mines, to have had one of the neatest, smartest, and all-around-coolest professors at Mines...Dr. Ed Cecil. Dr. Cecil has been my professor for Modern Physics, Astrophysics, and currently Nuclear Energy.  From the very first day that I embarked on this blog, I knew that I could get some detailed information and some worthy opinions from him and so now I have decided to pursue it further.

Today I did a short interview with Dr. Cecil about nuclear energy and the problems it faces today and in the future. First off I would like to start off with Dr. Cecil's credentials. In 1966, he graduated with a B.S. in Physics from the University of Maryland and in 1972 he received a doctorate in Physics from Princeton. So we now know he is smart...but what does he do? Dr. Cecil does research on fusion plasma diagnostics (sorry but this is over my head). One of the coolest things I discovered about him today was that he is the one credited with measuring the cross-section of a gamma-ray (in the basement of Meyer Hall)! How cool is that? Now on with the interview:

In terms of "science" ( i.e leaving politics out if you can) what do you see as nuclear energy's biggest obstacle? In other words what is the most significant obstacle impeding it from becoming the world's largest energy source?

For fission reactors by far it is the problem with waste disposal. Where do we put the stuff produced? Also, you have the fact that from the same technology you can make bombs.

What advancements, if any, must be made in nuclear energy technology before America will accept it as say France does?

Once again...waste disposal. You have this plan to put it in Yucca Mountain, Nevada but of course Nevada is saying "noooo". It sounds like a great idea until they ask to put it in your state. What it's going to take for nuclear energy to be accepted in America is the people have to want it. Right now there is a lot of unrest in the Middle East...we could see something like the oil embargo that took place before you were born. If this happens people might realize that we need another solution and the solution is nuclear...we just have to find a place to put the waste.

What do you think should be done with nuclear waste?

I like the idea of Yucca Mountain.  It makes sense...you don't have to worry about the waste getting into the ground water. Yucca Mountain is in the great basin and therefore there are no rivers that flow out of that area so the nuclear waste is just gonna sit there.

What is your take on France's underwater nuclear reactor plans?

If having underwater nuclear reactors prevents LOCA's (Loss of coolant accidents) then it sounds like a good idea. But anytime you place something underwater where it is harder to monitor and you have a liquid environment things are going to be more difficult. I do like the idea of small reactors though, if something is smaller it has the potential to be safer because it is easier to control, you also have less Plutonium produced, and it should be a lot easier to manufacture.

In 50 years where do you hope nuclear energy in America will be?

Fifty percent nuclear and fifty percent solar...no more oil.

For all those who stand against nuclear energy...if you could tell them one thing what would it be?

Consider the alternative. You have this idea of fossil fuels causing global warming and even with all the politics you have to admit there is a lot of data there.

In the end, I hope you all found this interview as interesting as I did. I think it just goes to show that even those highly in favor of nuclear energy understand that it is not a perfect system yet. However, instead of putting nuclear energy down and claiming that it will never work we should research and find a way to make it work for us. We already see that France is doing just fine with it...what are we waiting for America?