The Energy Challenge: Nuclear Waste Overview

Note:  The following is the first post in a series authored by CogCommenter Scott K, a real-life nucular nukleeyar nuclear - whew! - engineer.  Energy is a hugely important issue, one that touches upon everything from the state of our economy, to America's foreign policy all the way to climate change.  Scott will, I hope, be contributing several articles.

Stephen asked me if I'd be interested in doing some guest posting on the subject of nuclear power, since I work in the field. Naturally, I was shocked that he wanted something other than ranting, but I'm glad to help out Cogblog in my own little way. He suggested kicking this off with a post on nuclear waste issues (here, I will focus on spent fuel from nuclear power reactors-- other kinds of nuclear waste require different treatment.) Let me go on record here as saying that I am a supporter of nuclear power for the short-to-intermediate term, but do not claim that nuclear power is the alpha and omega of clean electrical power generation. I will generally give my reasons for different positions, but I hope to present information in a fashion that allows you to draw your own conclusions. Debates in comments are certainly welcome.

So, what are we talking about here? The fuel used to power nuclear reactors is contained in fuel assemblies. In the US, these fuel assemblies consist of square lattices of 12-foot cylinders of zirconium alloy material slightly over 1/2 inch in diameter, called "cladding", which contain the uranium dioxide ceramic pellets and the various fission byproducts that appear as the fuel is utilized. The lattices run from 8 x 8 to 17 x 17, depending on the design and the plant type, and can also contain fission-controlling products (which is outside the scope of this discussion), structural material, and different features to promote desirable flow characteristics or catch debris. Square lattices are the norm for the most part, however, Russian reactors use hexagonal lattices. After these fuel assemblies are used, they are moved to spent fuel pools to sit around until something is done with them. These spent fuel pools are essentially large swimming pools with storage cells at the bottom. The water acts as both a cooling medium and a radioactivity barrier.

Back in the early 1980s, various nuclear plant operators who built nuclear plants were required by law to sign contracts with the Department of Energy that established an arrangement in which the operators would make a payment of $0.001 per kWh into the Nuclear Waste Fund (note that provisions in the law made this fee retroactive to all waste generated prior to the establishment of the fund). The federal government then would assume the responsibility for using this money to dispose of the waste, beginning no later than January 31, 1998. This made a lot of sense at the time because the government wanted to maintain control of the treatment of such material during the Cold War era. As all of you probably know by now, that date has long come and passed, and the government has not yet started taking delivery of spent fuel (Ed. note:  cf here for DOE discussion of temporary storage sites for spent nuclear fuel), creating a fiscal/technical/political mess that has not yet been resolved to the satisfaction of all parties involved. However, it is worth noting that nuclear power generation is the only major modern electricity generation option that internalizes the costs of waste management, a fact that has only recently begun to be incorporated in cost comparisons between nuclear power and other sources (i.e., by incorporating carbon tax costs).

As of September 2008, just over 16 billion dollars have been paid into the NWF. A little over $3 billion remain outstanding in one-time fees (primarily fees to pay for electricity produced prior to the enactment of the law establishing the NWF). In addition, just over $12 billion has been accumulated in interest (much like the Social Security trust fund, the NWF funds have been used to buy Treasury securities, less any money appropriated by Congress to nuclear waste program activities). Out of the $30 billion total in or owed to the NWF, a little over $10 billion has been paid to date. Due to the government's failure to start accepting waste at the appropriate time, however, the costs are escalating because utilities have sued for breach of contract in order to recover expenses incurred in using alternative temporary storage methods, such as re-racking spent fuel pools for higher density storage and dry cask storage. In addition, DOE has had to deal with its own waste from research and nuclear weapon projects. Over time, even more costs may be incurred if plants are decommissioned and all that remains is the waste, in which case the expenses of the security force, maintenance workers, etc. are completely due to the waste. These costs are being covered from the Judgement Fund and DOE's budget, not from money in the NWF, but nevertheless are costs to the taxpayer resulting from the failure to resolve this issue.

Let's look at what the US is doing about this. Up until recently, essentially all of the eggs had been placed in a basket called Yucca Mountain. The concept seems simple enough: just build a secure repository deep underground, stick the spent fuel there, and close it up permanently. However, the project has been beset by multiple problems, including but not limited to managerial failures, technical issues, state non-cooperation, congressional underfunding, and political opposition. (Note: by "problem", I mean from the point of view of completing the project.) At this time, it is looking likely that if Yucca Mountain is used for spent fuel storage, it won’t be ready and licensed for more than a decade, possibly two. Recently, the government has been making some steps towards the idea of reprocessing, most notably the GNEP (Global Nuclear Energy Partnership), but such efforts are in their infancy and it would take quite some time to develop and fund that route. One idea tossed around has been to use Yucca Mountain as a temporary storage until the fuel can be reprocessed. As far as I know, that idea hasn’t gained much currency. Deep geological disposal is also the preferred option for a number of smaller countries such as Sweden. Supporters of this option frequently reference the natural uranium reactors found in Oklo, Africa, where the evidence shows that uranium deposits formed the right conditions for a continued fission reaction in pre-Cambrian times, producing the usual fission products. In the roughly 2 billion years since that time, the end products have been safely immobilized despite the fact that they were not in an ideal form to prevent migration.

Reprocessing is an option that was selected by France, Russia, Japan, India, and the UK. (There were some smaller reprocessing plants built in Belgium, Germany, Italy, and the US, but they were all essentially prototypes not meant for full-scale commercial production. They were all shut down.) Reprocessing itself is actually merely one portion of a category of transmutation methods—converting the radioactive products in waste, especially the longer-lived ones, into stable or short-lived radioisotopes. In conventional reprocessing methods, the remaining uranium-235 (the isotope that does the fission work in modern light water nuclear plants) and plutonium produced by irradiation are separated and “recycled” into fuel, while other longer-lived radioisotopes are separated out to be irradiated in reactors designed for irradiation (as opposed to power production) and/or vitrified (immobilized in glass or synthetic rock). Separating out the longer-lived radioisotopes reduces the bulk of the waste to deal with, and irradiating or fissioning them leads to actinides that hold significant radioactivity for a period of just a few hundred years as opposed to a million years or more. The two main cons relative to burial are proliferation risks (due to the separation of plutonium and U-235, though some of the newer reprocessing technologies maintain these isotopes in a blend unsuitable for use in nuclear weapons) and cost (which has been a hot debate for some time, because much of the analysis relative to subterranean burial depends heavily on the assumptions that one utilizes). Even though the bulk of the waste is greatly reduced, some sort of disposal will still be necessary, most likely deep geological disposal, but the technical issues are much more manageable due to the shorter duration of radioactive lifetime and the reduced amount of waste to store.

I myself an a supporter of the reprocessing option, because it strikes me as the more sustainable and responsible method of dealing with the waste. I am not sure, however, of the feasibility of this option in the US due to a combination of politics and funding issues. Dealing with nuclear waste occupies such a strange territory in the general political discourse because the ideologically opposed groups are not so much ideologically opposed on the question of nuclear waste management; rather, they advocate based on the issue of nuclear power generation. Most nuclear power proponents do not seem to have very strong opinions on which disposal mechanism is best; they simply want something to get done (you can imagine the level of frustration stemming from politicians generally punting on making a firm decision). On the other hand, nuclear power opponents have no incentive to point towards a generally accepted method of nuclear waste disposal because that neuters one of their main arguments against nuclear power. As a result, nuclear waste issues are less of an issue to be debated and more of a football used for purposes of scoring points. Ultimately, the fact remains that there is nuclear waste sitting aroun

I realize that this post really does not do much more than sum up information that any interested party could piece together on their own from various Internet sources, but it seemed appropriate to outline the contours of this issue as a starting point. I would be happy to elaborate on specific areas based on my expertise and understanding of the pertinent issues within the industry in comments or in separate posts.

Comments

[oddjob]

On a very tangential note:

in which Shrub's Science Advisor reveals more, far more, than he realizes.

(Hat tip, Twoglasses.)

[Crissa]

I remember writing about this in fourth grade, which was also twenty five years ago.

What gets me is that we still haven't begun to build a system capable of reprocessing, even while we've managed to finally get rid of most of our chemical weapons in deep storage.

Once again, here's something that people say would cost too much, and yet, would cost less than a year of the Iraq war.

[drip]

I know little about the issue, but I agree with the post, because it confirms my suspicions. Hey, it's the inter-tubes, right? I get to decide what's correct. Marginally more seriously, I have asked pro- and o-pponents of nuclear power to point me to a place where I can get enough information to make up my own stupid mind. If you can provide such a service without attracting nuclear trolls, you will have done something valuable.

In particular, if you ignore waste (for a moment) nukes seem like a no-brainer to me. The Calvert Cliffs plant in Maryland has been chugging along for years. I don't know how expensive it is to run compared to other plants, but Pepco and BGE don't seem any worse than any other utilities. Operating with no coal, no oil, no rivers dammed up -- well, it just seems sensible. As for the waste, reprocessing seems the way to go, till we figure out a way to send it to space safely. France is OK with it and if terrorists getting their hands on it is the problem, well, there are lots of people out of work who could guard it. I look forward to more. Welcome.

[Sir Charles]

Scott,

Thanks for providing so much content in your content. I

I, too, tend to come down gently on the pro-nuke side, especially if it would mean the ability to retire a lot of these coal fired power plants. I think we should look to see what the Europeans have done and learn from them.

Do you know anything about of the vast amounts of water that these plants require to cool them and whether there is a reasonable way to mitigate that aspect of their environmental impact?

[oddjob]

if you ignore waste (for a moment) nukes seem like a no-brainer to me

I don't know enough about waste reprocessing to have a good opinion on this. I know I think it's extremely irrepsonsible to create a problem with a life longer than the entire history of human civilization, but otherwise the only quibble I make with the idea that it's a no-brainer is that, from what very little I understand (& I don't know a lot about the matter), there isn't enough ore out there for this to be more than a short- or medium-term answer to our energy needs. If the waste can be handled in such a fashion as to not be a serious problem for the next several hundred thousand years-plus (or even the next thousand would be nice thank you very much), I agree it ought to somehow have a place at the table of energy solutions.

But only if!

[Scott K]

Yay! Questions to answer!

Crissa/drip regarding reprocessing:
Much of the political problem vis-a-vis proliferation with reprocessing is in no small part due to the fact that the Indian atomic test in 1974 was performed using plutonium that was reprocessed from fuel in a research reactor supplied by Canada for peaceful use. Prior to this point, reprocessing was being promoted on a worldwide scale. After that, the Ford administration began to take the approach of preventing the spread/use of reprocessing technology. A number of reprocessing plant orders were scrapped thanks to U.S. pressure (destined for various countries such as Pakistan, South Korea, and Brazil). The Carter administration imposed a ban on reprocessing, and the Reagan administration reversed it but was clear that private industry was going to have to take the lead on it (which nobody did, due to the cost involved). Even today, there are still a lot of people who are skittish about how to move towards some sort of global reprocessing program without having the reprocessing technology spread or having reprocessing plants become terrorist targets or be vulnerable to theft (you really don't need all that much material for an atomic bomb).

The economics are also tricky, because you are essentially comparing it (on a cost basis) to deep geological disposal. But you have to make assumptions about what it will ultimately cost for a deep repository, i.e., given all the problems that program has had so far, does that impact the cost assumptions significantly enough to make a difference? Also, reprocessing assumptions typically focus on a simple reprocessing paradigm in which the energy extracted from a given amount of uranium is increased by about 30%. There are other possibilities, such as a closed cycle involving fast breeder reactors with reprocessing, which has the potential to increase the amount of energy from a given quantity of uranium by a factor of 50-60. Nevertheless, today uranium ore is just so cheap compared to reprocessing that it is not possible to make a strong economic case for it today-- which is why the private industry isn't touching it. The current spot price range for uranium is around $50/lb, and it would probably have to get up to the neighborhood of $250/lb before reprocessing is seen as a cost-competitive option.

I still support reprocessing, simply because being obsessive about monetary cost really ignores a lot of the non-financial externalities and I don't feel completely comfortable committing to something permanent that potentially could have an impact in a million years. I am, however, sympathetic to some of the concern about proliferation because, as I said, it doesn't take all that much material to make a bomb. The key issue, to me, is developing a plant design and system that causes great difficulty in diverting any material (even small quantities).

[Scott K]

Sir C, regarding water.

One thing that sometimes gets lost in the debate about cooling water needs for nuclear plants is that nuclear plants are fundamentally designed as boilers, just like fossil plants. If you were to replace a nuclear plant with enough fossil plants to generate an equivalent amount of electricity, you'd still need the same amount of cooling water. The reason nuclear plants get so much press on this issue is because nuclear plants generally take advantage of economies of scale by siting two or more reactors on one site (in the US, I believe the maximum right now is three, but in other countries, it can be more), and each nuclear reactor can generate a heckuva lot of energy. The biggest reactors in the US generate around 1,300 megawatts of electricity and are run at full power 24/7 because they are cheaper to operate that way and there are xenon transient issues (ask if you really want the explanation) that makes it impractical to switch them on/off rapidly. Thus, there is a lot of cooling water needed in one location instead of dispersed throughout the country.

To control the impact to the environment, nuclear plants operate under two limits. One is how high the temperature difference upstream and downstream of the plant can be. The other is the maximum temperature that the water downstream of the plant can be. Both of these limits are based in large part on environmental impact studies. In the US, there have been a couple of times in the recent past when plants had to drop their power level in order to avoid violating these limits. During the heat wave in Europe not too long ago, some plants received exemptions to exceed the maximum temperature limit, but I think that the government was caught between a rock and a hard place. So far, cooling water has not been a huge problem in the US but may become more of an issue in the future (note that use of water for cooling does not preclude use for other purposes, since the same water is returned back into the river and is isolated from the radiation-contaminated water in the plant). One solution to this problem is to build more air cooling capability (i.e., cooling towers). Utilities have not done this yet because there has not been a widespread problem with the thermal discharge limits, but if there are more issues and the NRC is a good regulator and holds the line, then utilities will simply have to build more cooling towers/ponds.

[Sir Charles]

Thanks Scott.

Of course some of my bias towards nukes is because my clients love them -- talk about a lot of man hours for pipe fitters.

Funny nuke story -- there was a public hearing about permitting a possibly additional nuke on an existing site on a day that one of my clients was having a meeting with me. The head of the local union indicated that we would have to finish the meeting by a certain time so that he and his members could get to the meeting early and grab all of the seats "before the Sahara Club showed up." I did not spit my coffee out, which is the mark of a seasoned professional.

[Scott K]

oddjob, regarding nuclear ore supply: the OECD NEA & IAEA Uranium 2007: Resources, Production, and Demand ("Red Book") indicates that at the beginning of 2007, total known recoverable uranium ore resources using a price of $130/kg U (just under $60/lb, which is a little above the current spot price but the spot price was at $100/lb about a year ago as part of the widespread commodity price escalation) was about 5.5 million kg. The current ~370 GWe produced by the world's power reactors require about 65,000 metric tons of uranium every year. That implies sufficient uranium to last for over 80 years. Of course, more nuclear plants being built would mean more uranium needed. But use of different technologies would change the picture-- for example, breeder reactors which would actively produce more fissile material than it consumes, or thorium-fueled reactors. Also, as the price of uranium goes up, lower and lower grades come into play, even including extracting uranium from seawater (up to 4000 million metric tons). Estimates of the available uranium supply really depend heavily on a number of different factors. In the big picture, I think that the uranium supply is by far the least of the problems that the nuclear power industry has. The reason I only support it as a near to intermediate term solution is the simple fact that uranium is not an infinite resource and while nuclear power compares very favorably to much of the other generation options today, that won't always hold true.

[ballgame]

Good post, Scott K. I for one remain implacably opposed to nuclear power on the basis of the radioactive waste issue. I say that while being completely cognizant of the dire impact of both peak oil and global warming. (FWIW, you make a good case for reprocessing over the current longer-term storage approach, but that strikes me as an awful lot like the old, "Would you rather be thrown off a cliff or have your teeth pulled out without anaesthesia?" kind of choice.)

I think any true cost/benefit analysis of nuclear power will find that its costs far outweigh its meager benefits once you incorporate the need to protect the waste for (as you note) a minimum of hundreds of years.

In addition, my impression is that such storage is dependent on a prescience about geological events which exceeds our actual scientific capacities. The reference to the Oklo radioactive deposits seems rather misleading. If there HAD been some geological event in that region of Africa during that time — like maybe an earthquake or volcano — which spewed the material into the atmosphere, we likely wouldn't be here to discuss it.

As an emergency response to the peak oil/global warming situation, I think advocacy of the nuclear option should only be entertained AFTER there's been a widespread acceptance of the reality that we are, indeed, in an emergency situation. That is, only AFTER we've made massive financial and cultural commitments to public transportation, energy efficiency, and renewable energy sources, which we haven't remotely begun to do.

In the mean time, nuclear power strikes me as the energy version of Credit Default Swaps: a completely predictable disaster waiting to happen.

[drip]

Funny nuke story Only here could what followed actually be funny. Sahara Club, indeed.

[Sir Charles]

drip

I did not advise the client that I was a member of the Sahara Club.

[Scott K]

Sir C, Sahara Club-- ha! I'm sympathetic to your distaste for endless chatter on such subjects. I work in an area where I don't have to worry about these topics-- I leave that up to the experts.

Funny story of my own... one of my friends worked for a different company for some time, and he informed me that on one occasion, a letter had to be sent out to the Nuclear Regulatory Commission. However, the secretary made a small typo and sent out the letter addressed to the "Unclear Regulatory Commission". They were not very amused.

[Scott K]

ballgame, I respect your position and only seek to pursue a productive discussion with the understanding that we may end it with a better understanding of each others' position, but without changing any opinions. That's just the way it is, sometimes.

I agree that the waste issue may be considered as an argument against nuclear power, but that still doesn't change the fact that there is already nuclear waste to be dealt with, and it is with that in mind that I wrote the guest post discussing the current state of affairs and what could be done or is being done. I left the extended issues for another post or comment. Now that you mention it, here goes...

Energy efficiency... I wonder what you mean by this, because there are a lot of programs currently being used to improve efficiency, varying from audits of homes/businesses to reduce energy use, changing daylight saving time shifts, transitioning to CFL bulbs, and so on. At some point, you ultimately have to start simply cutting out whole areas of energy use, which is difficult to implement due to the potential pain for the people involved. Also, many of the popular policy proposals right now for transportation involve the idea of electrifying as much as possible, ranging from electric rail to plug-in hybrids (or even pure electric vehicles, such as my motorcycle). That means a large increase in need for electricity that could very well swamp gains from energy efficiency initiatives.

You and I are on the same page vis-a-vis the need to move to an alternative energy infrastructure in the future. I think we mainly disagree on how to get from here to there. Solar cell manufacturing is a very energy-intensive process, mainly due to processing silica to produce silicon. Since most of the energy used is produced by fossil plants, the net carbon-emission addition to the environment is a good bit higher than that for nuclear power. Wind power is good, but I don't know if it can meet our needs on a large enough scale to replace a sufficient amount of fossil-fueled generation. On top of that, the current electric grid is not ideally set up for intermittent energy, so there will need to be large infrastructure investments. So I see nuclear power as a short-to-intermediate aid in cleaning up our current generation as we move away from fossil power to renewable energy-- a stepping stone, so to speak. Obviously, if the energy being used in manufacture of solar cells is not derived mainly from fossil fuels, the net impact on carbon emissions will be much lower.

Engineering analyses of Yucca Mountain involve multiple safeguards to address all kinds of "what-if" scenarios, rather than simply assuming that they won't happen. It is true that particularly extreme situations may not be adequately covered, but the vast majority of such situations would pose many more problems to mankind than what happens to the nuclear waste. To take your Oklo example, if a scenario such as you describe happened, there would be a lot of bigger problems, i.e., one theory proposed for the extinction of dinosaurs involves a massive volcano eruption. The issue that is more pertinent at Oklo is that the radioactive material did not enter the water table or otherwise migrate to areas where it could have an impact. Science/engineering isn't a perfect process, of course, but no industrial process is truly perfect. If you had an accident at a solar-cell production facility that resulted in an explosion and a plume of silica into the air, that probably would not be very desirable either. I have my own bones to pick with Yucca Mountain due to my basic sense that it is really just being considered as the most politically palatable (which is debatable) and cost-efficient method of disposal, rather than the most responsible method, but that does not necessarily invalidate the work of the engineers and scientists involved.

[ballgame]

I agree that the waste issue may be considered as an argument against nuclear power, but that still doesn't change the fact that there is already nuclear waste to be dealt with …

True enough, Scott K, and a difficult argument to rebut if one believes — as I do — that we should prioritize the cessation of nuclear-waste-generating activities. I guess I would ask a similar question from a different angle, though: if our current social and political systems are incapable of responsibly handling the toxic materials we've already produced, how can the expansion of such activities be morally acceptable when the increase of such materials can only heighten the likelihood of a potentially permanent catastrophe? Where is the limiting factor? If 12 nuclear plants are acceptable, why not 24? 240? I think the only sane approach is, "No more."

there are a lot of programs currently being used to improve efficiency, varying from audits of homes/businesses to reduce energy use

These are important but token efforts. If the U.S. were serious about energy efficiency, we would have gasoline taxes on par with what Europe charges; mass transit systems that would allow substantial numbers of people to live without cars; mandatory flex time and telecommuting regulations that would staunch rush hour traffic jams; and an approach to land ownership and zoning that would prevent such absurdities as workers in D.C. commuting from homes in Pennsylvania (to name just a few aspects of a genuinely serious national approach to our energy situation).

a large increase in need for electricity that could very well swamp gains from energy efficiency initiatives

That doesn't quite make sense. Leaving aside the technical issues of switching from the petroleum 'grid' to the electricity grid, if we're fueling cars with electricity instead of gasoline, by definition we're not using that gas anymore. At worst, you could theoretically use that oil to generate the electricity. (Obviously any alternative approach to gasoline to run our cars would need to use significantly fewer hydrocarbons — else why bother switching?)

I'm glad we're on the same page as far as moving to alternative energy resources goes. I don't quite understand your point about solar cell plants and fossil fuels. Why couldn't the initial batches of solar cells be immediately installed on the solar cell production plants, so that all future solar cell outputs would be largely hydrocarbon-emission free?

Your understanding of the engineering issues involved at Yucca Mountain — and durability of its safeguards — obviously exceeds my own. It remains unfathomable to me that we would use energy today and essentially place the burden of paying for that energy on untold generations of humanity to come. It also seems incredibly optimistic to believe that humans of unknown political institutions and perhaps only a dim understanding of the nature of the problem could be relied upon to deal responsibly with this waste when our own political system (which has complete knowledge of the issue) is almost incapable of doing so.

ballgame, I respect your position and only seek to pursue a productive discussion …

Same here, Scott K. Good faith discussions with those who hold views antithetical to one's own are sometimes the most interesting kinds. I've enjoyed reading your post and comments.