Energy From Thorium Discussion Forum

It is currently Oct 19, 2018 11:00 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 270 posts ]  Go to page 1, 2, 3, 4, 5 ... 18  Next
Author Message
PostPosted: Jan 23, 2007 2:28 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3820
Location: Alabama
Here's a question I have often wondered, as I've tried to understand the point of view of those who oppose nuclear power--how much of their opposition is driven by the longevity of nuclear waste?

If long-lived nuclear wastes are the main issue they have against nuclear power, then thorium could go a long way towards alleviating their concerns.

If on the other hand, waste is only the issue du jour, and a solution to the waste issue would simply cause them to harp on other aspects of nuclear energy, such as proliferation, potential terrorism, CO2 release from mining, and my favorite stupid one--thermal pollution.

I really wonder because I know there are people that are simply categorically opposed to nuclear power because it represents some other evil to them--whether it's democracy, capitalism, globalization, industrialization--whatever evil they feel like they want to attach to nuclear industry. I don't think I'll ever be able to change the mind of someone like that.

On the other hand, I often encounter colleagues who are well-educated, span the range of political inclinations, and yet are opposed to nuclear energy. These are the people who I really want to understand "why" because I think they might be reasoned with. And an issue I often seem to hear is the longevity of wastes.

For instance, last night I was listening to a podcast from Rod Adams' "Atomic Show". The guest was a mining and nuclear engineer from the University of Michigan. Well-educated, well-versed--no nuclear opponent by any stretch of the imagination, but certainly not as enthusiastic about the prospects of future nuclear energy as Rod was. He challenged Rod on several points, and one of his primary concerns about the expansion of nuclear energy was "what do we do with all the long-lived waste?"

Now this fellow knew what thorium was, and he spoke on several occasions about its merits. He knew the difference between a transuranic isotope and a fission product, and he had studied the geology of Yucca Mountain extensively. Perhaps he did not think that thorium fuel cycles were a realistic near-term possibility. But nevertheless, I perceived that this fellow was hesitant to endorse nuclear energy as a primary, dominant energy source for the world. To be quite honest, if it meant an enormous expansion of conventional uranium-fueled, once-through light-water reactors, I would be hesitant too.

So I will wonder, and perhaps some of you could offer your thoughts--do you think that the longevity of nuclear waste (meaning today's form of nuclear waste) is the primary issue that concerns most people about nuclear energy?


Top
 Profile  
 
 Post subject:
PostPosted: Jan 23, 2007 3:47 pm 
Offline

Joined: Dec 20, 2006 7:50 pm
Posts: 280
People dont understand nuclear waste, but that doesnt stop them from being concerned.

100 tons per GW year from a light water reactor is very small, but people only think of 100 tons as a huge amount of stuff that wouldnt fit in their garage. There is no need for any long term waste storage facility, but we're still paying billions for a bad one. In 100 or 200 years we'll just crack open the casks to get at the fission products and uranium anyways, if not sooner.

So yes, liquid fluoride reactors could have a huge political advantage because of the smaller waste output. The public still wont understand that 100 tons versus 1 ton of waste are both insignificant amounts from a waste handling perspective... They'll just know its 100 times less wasteful.

Liquid chloride reactors, if they could be made at similar cost, would have a huge advantage in that they destroy nuclear waste from light water reactors. Match them with the pyroprocessing/electrorefining techniques developed by ANL and you get to sell uranium back to the market, free fuel, and power.

Now the waste stream can be reduced even more with partitioning of the fission products into marketable and disposable fission products. The fission platenoids all have potential markets, as does the silver, xenon, etcetera. I guess thats a topic more suitable for the reprocessing section. I imagine the waste volume could be further reduced by over 50% and make money doing it.


Top
 Profile  
 
PostPosted: Jan 23, 2007 4:02 pm 
Kirk,

Based on my experience discussing this issue with friends and colleagues, I would estimate the factors that result in the general public's opposition to nuclear energy breaks down as follows:

Fear of a nuclear power plant accident - 50%
Concern about long lived nuclear waste - 35%
Concern about proliferation of nuclear material - 10%
Other - 5%

However, this is a good topic for a public opinion poll and I'm sure the nuclear power industry has done them already. Is there a way to get the information from such a poll?

Thorium scores quite well with regards to these three "fear factors".

Chris


Top
  
 
 Post subject:
PostPosted: Jan 23, 2007 4:06 pm 
Offline
User avatar

Joined: Nov 30, 2006 9:18 pm
Posts: 1946
Location: Montreal
You know, its fascinating that neither people in the public in general, nor politicians, seem too concerned about the longevity of carbon dioxide, when the fossil power industry (coal, gas, oil) talks about the capture, sequestration and deep storage of CO2.
Unlike radioactive substances, CO2 doesn't decay away: the full load could leak out at any time in the distant future.
Beats me how people reason.


Top
 Profile  
 
 Post subject:
PostPosted: Jan 23, 2007 4:13 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3820
Location: Alabama
The guy on the interview said the same thing about CO2, but as I was running along and listening to my MP3 player, I thought to myself, "it's pretty hard to get scared of CO2 when I'm exhaling it with every breath."

Scientifically, I know that all the CO2 we're releasing poses problems, but emotionally, I can see how nuclear waste seems so much scarier.


Top
 Profile  
 
 Post subject:
PostPosted: Jan 23, 2007 6:28 pm 
Offline
User avatar

Joined: Nov 30, 2006 9:18 pm
Posts: 1946
Location: Montreal
OK, let's look at the very long-lived radioactive waste from a modern 1000-MW electrical coal plant:

Coal heat content = 33649 kJ/kg
Tons of coal burned per year = 2.46 million
Carbon fraction = 81.9%
Ash fraction = 7.8%
Sulfur fraction = 0.8%
Fly ash emitted per year = 957 tons
Uranium emitted per year = 950 kg
Fraction of uranium in fly ash = 25%
Fraction of uranium in bottom ash = 75%

Of course the uranium is almost entirely U-238, with a half-life of 4.51 billion years (the only time you hear about this particular figure from the antis, is when they talk about DU weapons used against islamo-fashists in Kuwait & Iraq, or ultra-nationalists in Serbia).

Moreover, that uranium is accompanied by the entire decay chain of daughter radionuclides, including Radium, Polonium, Bismuth, Radon gas, etc.

We all know where the 25% of uranium in fly ash goes (238 kg per year, dispersed very dilutely in the surrounding environment), but is anyone concerned about the 75% (713 kg per year) of uranium in bottom ash, and how this gets disposed of ?
Heck, this stuff isn't even regulated.
And for pretty good reason -- there are far greater threats from coal burning, such as the emissions of mercury -- another permanent, non-decaying poison.


Top
 Profile  
 
 Post subject:
PostPosted: Jan 23, 2007 7:04 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3820
Location: Alabama
You don't have to convince me...I definitely think coal is much more dangerous. But as I learned from reading "Big Coal", the last thing the coal industry wants is for you to think about images like this:

Image


Top
 Profile  
 
 Post subject: Longevity
PostPosted: Jan 24, 2007 9:08 am 
It doesn't do any good to point out the negatives on competing fuels. The problem remains nuclear waste's unique power as an image. More movie monsters have been created by nuclear waste over the last 50 years than by mining cave-ins or lung disease.

Longevity remains a formidable PR problem because what many people think of as "glowing, pulsating homicidal goo" remains alive to poison further generations. Now how on earth is talking about coal dust going to neutralize such images? It is perceived as merely changing the subject rather than addressing the question.


Top
  
 
 Post subject:
PostPosted: Jan 24, 2007 9:27 am 
Offline
User avatar

Joined: Nov 30, 2006 9:18 pm
Posts: 1946
Location: Montreal
How is uncontained radioactivity in coal ash different from contained radioactivity on nuke plant sites ?


Top
 Profile  
 
 Post subject: Longevity
PostPosted: Jan 24, 2007 9:38 am 
You're offering a comparison with an alternative.

While perfectly sensible, unfortunately that doesn't do anything to anything to answer the fearful question. Nuclear installations are the ultimate NIMBY, focal points of public concern over incompetent personnel, terrorist sabotage and three-eyed children.

Mention coal's problems and eyes glaze over and ears close. Mention instability in the earth at Yucca Flats and your listener instantly comes alive.

Never underestimate the power of ideas, and this is one that resists comparisons.


Top
  
 
 Post subject:
PostPosted: Jan 24, 2007 9:55 am 
Offline

Joined: Dec 01, 2006 12:26 pm
Posts: 7
Spamming dry data to the public is not the right method.
Possible exception : If the waste is 300 years instead of 100 000, that might have an effect on public opinion. If the plants are put beneath ground and sea level, acceptance might be higher.

Selling in the fact U232 is resistant to proliferation because any unauthorised handler signals his location to global satelittes or risks frying himself, is probably a PR-challenge equal to improving George Walker Bush's opinion ratings.


Top
 Profile  
 
 Post subject:
PostPosted: Jan 24, 2007 9:59 am 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3820
Location: Alabama
I think I have to agree with PanSkeptic here--if we think about it scientifically, we all know the facts. But the vast majority of people don't think scientifically. And my original question is "is the longevity of (today's once-through, uranium-fueled, transuranic-laced) nuclear waste the primary source of public fear about nuclear energy?"

We know that the radioactivity levels of even conventional LWR spent fuel has dropped dramatically after 300 years (after the fission products essentially decay away), but the public perception is that this stuff is "dangerously radioactive for tens or hundreds of thousands of years". Otherwise, why have a place like Yucca Mountain?

Now we know that the long-term radioactivity of the waste is dominated by the transuranics (plutonium, etc.) and that a thorium fuel cycle operating on thorium/U-233 can produce waste that essentially consists only of fission products that will decay away in a few hundred years.

If the public could be made to know that a pure thorium nuclear fuel cycle (implemented in a full-burnup reactor like a liquid-fluoride reactor) could eliminate the transuranic waste problem, would they find that compelling and could it reduce the number of people opposed to a large-scale deployment of nuclear (in this case thorium) energy?


Top
 Profile  
 
 Post subject: Longevity
PostPosted: Jan 24, 2007 10:12 am 
Will a shorter decay period help? My guess is (that's all it is and your mileage may vary), only incrementally.

I suspect most people have trouble seeing the difference between 300 years and a gazillion years. It's long enough for their grandchildren to be poisoned, and that's probably as big a time span as most people can comprehend. Oh, maybe great-grandchildren for those with visionary time horizons.

I think the notion of encasing waste in earthquake-resistant glass blocks has traction, but ideally, people want the stuff vaporized, expunged, gone, forgotten, reduced to zero, removed from the planet. Maybe we could shoot it into space?


Top
  
 
 Post subject:
PostPosted: Jan 24, 2007 10:43 am 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3820
Location: Alabama
The decay is exponential--most of the waste has decayed to stability in a year. The mention of 300 years is driven by the two most active decay products after the first decade or so--strontium-90 and cesium-137. They each have 30 year half-lives, and a good rule of thumb is after ten half-lives, something's essentially gone. That's where 300 years comes from. It's not like the waste is all there in year 299 and then in year 300 it's all gone.

Here's a good chart:

Image


Top
 Profile  
 
 Post subject:
PostPosted: Jan 24, 2007 10:55 am 
That's impressive.

Nobody knows this.

Perhaps you could come up with a catchy way to encapsulate this, along the lines of "90% gone within a year?"

No, I don't pretend to know the science, it's outside my area of competency, but there must be some way of formulating your concept that would fit inside a bottle cap or on a bumper sticker. Something like "Member FDIC" or "Safe when taken as directed," or "Ask your doctor" or "Except in Nebraska."

Something that sticks in the mind.


Top
  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 270 posts ]  Go to page 1, 2, 3, 4, 5 ... 18  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group