Month

It’s no secret that I have not supported the Waxman-Markey cap-and-trade bill, but I want to commend Rep. Joe Sestak for trying to make some lemonade out of those lemons with his amendment to the bill:

AMENDMENT TO HR 2454
OFFERED BY MR. SESTAK OF PENNSYLVANIA

Page 296, after line 6, insert the following new section:

SEC. 199. STUDY.

Not later than February 1, 2011, the Secretary of Energy shall transmit to the Congress a report showing the results of a study on the use of thorium-fueled nuclear reactors for national energy needs. Such report shall include a response to the International Atomic Energy Agency study entitled “Thorium fuel cycle – Potential benefits and challenges” (IAEA-TECDOC-1450).

Rep. Sestak’s office then issued a press release where they highlighted the importance of thorium and the value of this study:

The bill included an amendment proposed by the Congressman to require the Secretary of Energy to study how Thorium, a nuclear element, can be used to address our energy needs. The Congressman believes that nuclear energy needs to be part of our mid-term energy policy to increase domestic energy production and reduce our emissions. In addition, he understands that we must overcome nuclear waste issues. Under the amendment, Thorium could be used with or as a substitute for Uranium in nuclear reactors. Thorium-powered nuclear reactors have the potential to be more efficient and produce less than 1 percent of the waste of today’s Uranium nuclear reactors, while emitting no greenhouse gases. Using Thorium reactors do not breed plutonium, and can, in fact, be designed to “burn” plutonium into non-weapons grade material and, thus, decrease weapons proliferation. Additionally, Thorium nuclear reactors can help eliminate spent Uranium.

Thank you for your leadership, Rep. Sestak!

IAEA-TECDOC-1450 is a document that was issued by the International Atomic Energy Agency in July of 2005. It is a fairly comprehensive treatment of the use of thorium in many different types of nuclear reactors.

Most of the attention in the paper is focused on the use of solid thorium oxide fuel assemblies in light-water and heavy-water reactors, with some consideration of how to use thorium in liquid-metal fast breeders as well.

On pages 29 and 30 of the document there is a description of a “molten-salt” reactors that could utilize thorium as well.

The overall benefits of thorium are described in TECDOC-1450 as:

(1) Thorium is 3 to 4 times more abundant than uranium and widely dispersed worldwide.

(2) Unlike the abundant isotope of uranium (uranium-238), the fissile daughter of thorium formed by neutron absorption (uranium-233) produces enough neutrons from fission per neutron absorption to sustain the further conversion and consumption of thorium indefinitely in a thermal spectrum reactor. Uranium-238 can only accomplish this in a fast-spectrum reactor.

(3) Thorium can be consumed as a nuclear fuel with very little production of actinides heavier than uranium (transuranic elements), which are the primary sources of long-term radiotoxicity in existing uranium-based nuclear fuel.

(4) Thorium has only a single valence state (+4) while its fissile daughter uranium has two major valence states (+4 and +6) which facilitates easy chemical separation of bred uranium from thorium.

(5) Thorium–based fuels and fuel cycles have intrinsic proliferation-resistance due to the formation of 232U via (n,2n) reactions with 232Th, 233Pa and 233U. The decay of 232U includes two decay products (212Bi and 208Tl) that emit hard gamma radiation that make the detection of U232-contaminated fuels exceptionally straightforward.

The IAEA study also identified challenges related to the use of thorium as a nuclear fuel. These included:

(1) The high melting point of ThO2 (3500C) makes fabrication of solid thorium-oxide based fuels challenging.

(2) Thorium-oxide-based nuclear fuels are chemically inert and difficult to reprocess.

(3) The 232U contained in thorium-based fuels has high radiation levels which make solid fuel fabrication difficult using existing procedures.

(4) In the conversion chain of 232Th to 233U, 233Pa is formed as an intermediate, which has a relatively long half-life (~27 days) and a significant neutron-absorption cross section. If 233Pa absorbs a neutron before decaying to 233U, the consumption of thorium as a fuel is thwarted and 234U is formed instead. Ideally, 233Pa would be isolated from the neutron flux as soon as it is formed and then reintroduced to the reactor after it has decayed to 233U. This step is highly impractical in most solid-fueled reactors, and so overall neutron flux (and power) must be reduced to reduce neutron-absorption in 233Pa. This reduces the economic viability of the reactor design.

The challenges related to the use of thorium in a solid-fueled reactor were recognized early in the Atomic Age by early pioneers such as Nobel Laureate Eugene Wigner and Dr. Alvin Weinberg, the inventor of the light-water reactor. In order to realize the benefits of thorium as a nuclear fuel while circumventing the disadvantages, they proposed that thorium be utilized in reactors whose fuel was in a fluid form. This would enable the elimination of fuel fabrication that was difficult with thorium, as well as facilitating the rapid reprocessing of thorium fuels, taking advantage of the chemical differences between thorium, protactinium, and uranium to achieve simple chemical separation of the fuels.

Further research at the Oak Ridge National Laboratory in the early 1950s identified liquid-fluoride salt mixtures as the ideal medium in which to utilize thorium as a nuclear fuel. This is because only thorium in fluoride form (specifically, thorium tetrafluoride) can truly be in solution, rather than a suspension or a slurry. To reduce the melting temperature of the thorium tetrafluoride, they proposed that it be mixed with fluoride salt mixtures that were chemically compatible with high-nickel container materials and also possessed attractive neutronic properties, specifically lithium-7 fluoride and beryllium fluoride. In such a liquid-fluoride reactor, thorium would absorb neutrons from the fission reaction and be transmuted first into protactinium, and then by decay into uranium. The chemistry of uranium and thorium enabled very easy separation by fluorination of the uranium from a tetrafluoride to a gaseous hexafluoride. The chemistry of protactinium also permitted separation from thorium, potentially allowing a high-flux thorium reactor to operate while still minimizing fuel losses to protactinium absorption. The fluoride salt mixtures of the reactor (7LiF-BeF2-233UF4 in the core and 7LiF-BeF2-ThF4 in the blanket) were very chemically stable and thus would allow low pressure operation at high temperatures, which meant that high-temperature reactor operation was possible. This in turn implied excellent power conversion efficiencies if coupled to an appropriate power conversion system such as a closed-cycle gas turbine, as well as applications enabled by high temperature reactors such as sea water desalination from waste heat, thermo-chemical generation of hydrogen, and the synthesis of other transportation fuels for a variety of applications.

The low-pressure operation of the reactor also permitted the reactor to incorporate many impressive passive safety features, such as a freeze plug in the bottom of the reactor vessel that would melt if the reactor overheated and would drain the core fluids into a vessel specifically intended for the passive removal of decay heat, rather than one that needed to sustain nuclear operation. The capability of the fluoride reactor to productively utilize thorium as a nuclear fuel, while avoiding its principal disadvantages, indicate that the liquid-fluoride thorium reactor should be the baseline reactor design considered for the successful developm
ent of the thorium resource.

File this in the “you have got to be kidding me” category:

Sears Tower to Be Revamped to Produce Most of Its Own Power

One can only imagine the “impact” that will be felt on the ground when one of these wind turbines throws a blade in the 80 mph winds and -30F temperature winter weather of Chicago. Hope there’s no one in the impact site. I wouldn’t want to be the insurance company trying to insure this craziness.

All of this foolishness for solar and wind that, maxed out, looks like it would produce about 100 kW of power on the best (sunny and windy) day. I’m guessing that’s about 1% of the power this building draws in normal operation.

While I was at the ANS Conference in Atlanta, I had the good fortune of attending a presentation by Dr. Jan Uhlir of the Nuclear Research Institute located in Rez in the Czech Republic. During his presentation, Dr. Uhlir described the research work going on at the NRI and talked in particular about their recent research into thorium-fueled fluoride reactors.

Here is a diagram of their overall approach:
Dr. Uhlir is the head of the Fluoride Chemistry Division at NRI, and has come to some of the same conclusions about thorium-burning fluoride reactors that I have, namely, that a two-fluid fluoride reactor (where the thorium-bearing and uranium-bearing fluids are kept separate) has particular advantages in performance and ease of reprocessing over a single-fluid fluoride reactor (where thorium and uranium-bearing salts are mixed).

This is the diagram for the one-fluid reactor:
This is the diagram for the fuel circuit of the two-fluid reactor:
This is the diagram for the fertile circuit of the two-fluid reactor:
After the presentation I was able to have lunch with Dr. Uhlir and he told me more about the NRI and their research there. NRI is actually a private research institution, whose primary shareholder is the Czech power company, which is turn is owned by the government. NRI’s work in fluoride reactors began with an examination of transuranic-burning (transuranics are the long-lived waste from current reactors) but progressed to examining thorium-burning reactors as a way to avoid making transuranics in the first place.

I was very impressed by Dr. Uhlir’s work and by his personal zeal for the project–I hope that the United States can catch up to where these Czech researchers have already reached! And I hope that the US and the Czech Republic can collaborate to bring thorium-fueled liquid-fluoride reactors to fruition!

Here is a link to Dr. Uhlir’s presentation.

Thorium Discussion Forum thread on this topic

Lately I’ve heard some descriptions about the potential of “thorium” that were very specific to the form of thorium that you would use in solid-fueled, water-cooled reactors–thorium oxide.

Thorium oxide, or specifically thorium dioxide (ThO2) is the solid form of thorium that one would use in a light-water reactor or in a pebble-bed reactor, perhaps even in a sodium-cooled fast breeder. Thorium dioxide is VERY chemically stable and has the highest melting point of any oxide–3300 degrees Celsius. This is why it is sometimes said that “thorium” can’t have a meltdown in a nuclear reactor–they’re talking about thorium dioxide fuel.

The problem with thorium dioxide is that it is extremely difficult to reprocess the fuel and extract any uranium that has been bred into the fuel from being in a reactor. To reprocess thorium oxide fuel, you first have to convert it into another chemical form (a nitrate) and do the chemical separations in this form. In fact, thorium oxide is so difficult to reprocess that this has been a major disincentive to use thorium dioxide as a nuclear fuel.

But there’s a much better option: thorium in a fluoride form, instead of an oxide. Specifically, thorium tetrafluoride (ThF4) is a form of thorium that’s EVEN MORE chemically stable than the oxide, but unlike the oxide it has a major advantage:

You can reprocess thorium fluoride without changing it into something else!

The reason for this magic has to do with the chemistry of uranium fluoride as well. There’s two basic forms of uranium fluoride–one with four fluoride ions (the tetrafluoride) and one with six fluoride ions (the hexafluoride). The tetrafluoride of uranium is stable in a salt solution, like sugar dissolved in water, but the hexafluoride is a gas and will come out of a solution.

This is the perfect trick for a thorium reactor, because you want to be able to separate the bred fissile product (uranium) from the parent material (thorium). In oxide form, this involves pulling solid rods out of a reactor and changing their chemical form to achieve reprocessing. In fluoride form, you don’t have to change the chemical form–you can process the fuel just the way it is, by shifting the small amount of uranium in the thorium from a tetra- to a hexafluoride.

It’s a trick that’s so SWEET that one has to wonder if we aren’t meant to build fluoride reactors that use thorium as a fuel!

A couple of months ago, I felt like a nuclear “Indiana Jones” when a trip out to Iuka, Mississippi took me face-to-face with the ruins of a nuclear reactor. Or maybe it was more like an episode of “LOST” where they find a four-toed statue. But there I was looking at a huge, unfinished cooling tower, a turbine hall that looked pretty well completed but abandoned, and a containment dome whose rebar had been completely overgrown by vegetation.

Further investigation led me to discover that this was once TVA’s Yellow Creek Nuclear Plant, begun in 1978 and shut down in 1984 after the expenditure of billions of dollars. Yellow Creek never made a watt of power, but its shutdown broke the hearts of the local community, who had thought that the coming of the reactor would lead to an improvement in the local economy. Later efforts by NASA to build solid-rocket boosters at the site in the late 1980s also led to hope that was dashed a few years later when the effort was cancelled.

All of this got me curious about what TVA planned to do with nuclear power back in the early 1980s. And what I found out got me excited:

It looked like TVA planned to replace their coal plants with nuclear plants.

TVA had a very ambitious nuclear construction schedule underway in the late 1970s, and they had stopped building coal plants altogether. Here were the plants they planned to build:

Browns Ferry 1, 2, 3
Sequoyah 1 and 2
Watts Bar 1 and 2
Bellefonte 1 and 2
Yellow Creek 1 and 2
Phipps Bend 1 and 2
Hartsville 1, 2, 3, 4

The ones in blue are reactors that ended up getting built and operated.

The ones in green are under currently under construction.

The ones in red were cancelled. Mostly in 1984 but some in the years to follow.

I began to wonder what TVA would have been like if they had built these reactors. Then I correlated which coal plants they might have been able to shut down if they had gone ahead and built the reactors.

If they would have built Yellow Creek 1 and 2 they would have replaced the Colbert coal plant (1198 MWe, finished 1965) and the Allen coal plant (753 MWe, finished 1959). Colbert consumes 8,900 tons of coal per day and Allen consumes 7,200 tons per day.

If the Bellefonte 1 and 2 reactors were completed they would have been able to shut down the Widows Creek coal plant (1629 MWe, finished 1965). Widows Creek consumes 10,000 tons of coal per day and was the site of a gypsum leak in January.

If the Watts Bar 2 reactor had been completed it would have replaced most of the power generation of the infamous Kingston coal plant (1456 MWe, finished 1955). Kingston consumes 14,000 tons of coal per day and was the site of a huge coal ash spill on December 22, 2008.

The Phipps Bend 1 and 2 reactors would have replaced the Bull Run coal plant (870 MWe, finished 1967), the John Sevier coal plant (712 MWe, finished 1957) and the rest of Kingston. John Sevier is now targeted for shutdown and replacement by a natural-gas-fired plant because of a judicial judgement against the emissions at John Sevier. Bull Run consumes 7,300 tons of coal per day and John Sevier consumes 5,700 tons/day.

The huge Hartsville complex (4 reactors) would have replaced Gallatin (988 MWe, finished 1959), Shawnee (1369 MWe, finished 1957), and Johnsonville (1254 MWe, finished 1952). Gallatin consumes 12,350 tons/day, Shawnee consumes 9,600 tons/day, and Johnsonville consumes 9,600 tons/day. Building Hartsville would have made an incredible difference in TVA’s future.

This would have left Cumberland (2530 MWe, finished 1973) and Paradise (2273 MWe, finished 1970) as the only coal plants on the TVA grid, and it’s likely at some point these would have been replaced with nuclear too.

Grand total: 85,000 tons of coal each day that TVA wouldn’t be burning.

Now, I read an article today called “A new TVA energy strategy” that says that TVA should avoid nuclear power and focus on renewables. Well, I’ve got news for the author–TVA hasn’t built a coal or nuclear plant in 25 years and HAS been focused on renewables for 15 years now, and they haven’t shut down a coal plant yet!

It may be too late to finish Hartsville, Phipps Bend, or Yellow Creek, but it isn’t too late for TVA to continue to push hard on the nuclear option–not only light-water reactors, but on liquid-fluoride thorium reactors that can potentially be sited at the same locations as the existing coal plants and take over their generation duties.

Thorium Discussion Forum thread on TVA news

Congressman Sestak Includes Key Provisions in National Defense Authorization Act

Thorium Study for Energy Efficiency

This provision directs the Secretary of Defense and the Chairman of the Joint Chiefs of Staff (JCS) to jointly carry out a study on the use of thorium-liquid fueled nuclear reactors for naval power, an important assessment of an energy source that has shown great potential to be more efficient for our military. While our nuclear Navy has thrived with a continuing record of zero reactor accidents, thorium may be more efficient than uranium as a fuel source. Massive fuel rods would not have to be utilized, and it produces only 1/2000th the waste of uranium. In domestic applications, waste can even be stored on-site, eliminating the necessity of facilities such as Yucca Mountain. Large deposits of thorium can be mined domestically in States such as Idaho, and we already have 160,000 tons in reserve.

Under a provision of the National Defense Authorization Act for Fiscal Year 2008, any new major combatant vessels for the U.S. strike force is required to be constructed with an integrated nuclear power system unless the Secretary of Defense submits a notification to Congress that the inclusion of an integrated nuclear power system in a given class of ship is not in the national interest. While the Congressman is not yet convinced that nuclear power for Naval ships is always cost-beneficial in the long term, if there are nuclear-powered vessels that continue to be built under Congressional mandate, then all options for the fuel source are worthy of consideration.

Thank you for your support, Representative Sestak!

I love my little daughters very very much and am very proud of them for just being themselves. But they’ve learned how to do something over the last few months that, as an aspiring nuclear engineer, makes me just about bust my buttons with pride. They’ve learned (almost) the whole periodic table:

When I was at the American Nuclear Society conference in Atlanta this week, I was hoping to show this ability to a group of peers, and the right opportunity presented itself in a session about public education. As the next speakers were setting up their talk on getting girls excited about math and science, I asked to show my own personal efforts to get two girls more interested in science.

Zoe, my oldest, is about to turn 7 and loves to read and ride her bike (which she recently learned how to do). This whole thing got started when I introduced Zoe to the idea that everything in the world is made out of “stuff” that is listed on a table called “the periodic table”. I printed a blank one out and taught Zoe how to fill it out, and that’s how all this got started.

Kaija is my second child, and she turns 5 tomorrow. When Zoe learns how to do something Kaija’s not far behind. Zoe learned how to ride a bike and Kaija, through sheer determination, learned four days later. So it’s not surprising that Kaija wanted to learn “the periodic table” just like Zoe did.

So here is the video, shot by my friend Rod Adams, who was also good enough to post it to YouTube. Enjoy!

And of course at the end when asked, “what’s Daddy’s favorite element?” they respond in unison:

“THORIUM!”

There’s a burger joint near Georgia Tech called “The Varsity” and when I was a grad student there people (not students) often mentioned it as part of some Georgia Tech “tradition” I dimly understood. No students seemed to ever talk much about The Varsity other than to tell me that the food was greasy and the service was bad. So I wasn’t terribly interested in eating there.

So I never did.

Until this last week. I went there and had lunch with my family, and guess what?

The food was beyond greasy, the service was bad, they botched my order, things were overpriced, and the whole place had a bad smell. People had told me these things, and they were basically right.

In a similar manner, I learned some things about the situation with Yucca Mountain and spent nuclear fuel (sometimes mistakenly called “nuclear waste”) that were as other and wiser people had told me.

At the American Nuclear Society conference in Atlanta this week, Ward Sproat spoke after lunch on Monday and talked about the REAL situation with Yucca Mountain. In short, it isn’t much like you’ve been told in the media.

Yucca Mountain isn’t dead, he told us, and can’t be until the Congress passes a new version of the Nuclear Waste Policy Act of 1982. He says that there are 39 states that like that act the way it is right now, and so that is why it won’t be changing soon. He also dispensed with a few other myths and alternate hopes that many of us have carried for some time:

Myth #1: There’s more than $20B in the “Nuclear Waste Fund”

There is not really any such thing. The money that is taken in from utilities every year to cover disposal (1/10th of a cent per kilowatt-hour sold) is used to defray the Federal deficit each year. It’s not sitting in an account somewhere, or drawing interest, or even being used to pay for Yucca Mountain. If/when Yucca is built it will be built from “then-year” funding, which gives the Congress every incentive to keep costs lower than expenses. I had kind of suspected this for a long time but Mr. Sproat confirmed it.

Myth #2: We could use “Yucca-money” to pay for interim storage somewhere…

Nope. The money collected (and let’s pretend like it’s really in a pot somewhere) can ONLY be used for the building of a federal repository. Nothing else. Not without changing the NWPA.

Myth #3: Recent judgments against the government by utilities are being paid out of the Yucca-money

Nope. They are being paid for out of a Department of Justice-fund meant to pay for judgments against the government, and the DOJ isn’t so happy about paying for DOE’s problems, especially when those judgements are some $500M a year and climbing.

Myth/hope #4: We could use the Yucca-money to develop advanced, closed-fuel-cycle reactors like LFTR.

As you might already guess, the answer is no. Not without a change in the NWPA.

Some smart people (like Per Peterson) told me things like this a long time ago, and like the people who warned me about the food at the Varsity, they were right.

Just added a few new blogs to the blogroll–part of my general sprucing-up of the site.

Areva’s new blog is on there. I’m proud of them for doing it.

John Wheeler’s blog is now on there. I met John at ANS09 and he’s a great guy.

And Keith Johnson’s Environmental Capital blog from the Wall Street Journal is on there. Keith did a piece on thorium a few weeks back that featured this blog and that definitely deserves getting on the list.