Book Review of “Super Fuel”

From Rob Potter on June 8, 2012 at 5:54 am:

I am going to slightly off-topic here to ask the commentators (who know a lot about the nuclear industry, from their very insightful comments) to comment in a similar vein on the Deuterium-cooled reactors being promoted in Canada. They call them “Candu” reactors (yuk, but we live in a world of marketing) and my simple analysis suggests they are an advantage in using essentially unrefined Uranium so no enrichment issues. Plus, the coolant is its own moderator so much of the engineering seems simpler.
(…) I guess what I am looking for is their downside since all I get here in Canada is the upside.
…

Everything you want to know should be in the Canadian Nuclear FAQ by Dr. Jeremy Whitlock. The Wikipedia CANDU reactor entry is also good.
As read here, besides using un-enriched uranium, they can burn “spent” fuel from conventional reactors, thorium, surplus weapons-grade plutonium, they can even get rid of waste actinides. The radioactivity requirements are so low they can keep recycling fuel and running it through until there’s practically no highly radioactive material left over. They’re also refueled while running, no shutdowns needed except for maintenance. They’re basically everything we could want from a fission reactor, if you’re not making bombs.
They’re also designed with many inherent safety features with automatic failsafes. It’d take deliberate sustained operator malfeasance to mess them up, or a severe natural catastrophe like a direct asteroid strike.
The major downside is, of course, at some point you’ll have radioactive reactor parts, and some lower-level waste. Although as the fuel technically never touches the heavy water coolant/moderator, on decommissioning you could just dump the D2O in the ocean where it occurs naturally and let it disperse. Can’t do that with light water reactor coolant.

The proof of design reactor ran for four years before it was shut down so it is not Unicorn Rainbows and Pixie Dust like much of green energy.
A quick look thru the newspaper will show that although we have had decades of experience with light water reactors we still have irritating problems related to the lifespan of the steam generator tubes. Humanity has been working with steam for hundreds of years.
The technical challenges of heat exchangers with water on one side and something else on the other side will surely be more daunting then a heat exchanger with water on both sides.
The history of other then water cooled reactors has been filled with ‘learning opportunities’.
http://www.gen-4.org/GIF/About/documents/16-Session1-4-OConnor.pdf
US DOE is pursuing research on ‘advanced gas cooled reactors’ .

Found in: Spector on June 8, 2012 at 10:43 am:
“http://ThoriumRemix.com – Kirk Sorensen is asked at Mount Royal University about using Thorium in a CANDU (heavy water) reactor. His response: No economic advantage to do so. Thorium can be effeciently consumed in a Molten Salt Reactor, not in a solid fuel reactor”
Full disclosure time, courtesy of Wikipedia:

Flibe Energy
Flibe Energy is a company that intends to design, construct and operate small modular reactors based on liquid fluoride thorium reactor (LFTR) technology.
…
Flibe Energy was founded on April 6, 2011 by Kirk Sorensen, former NASA aerospace engineer and formerly Chief Nuclear Technologist at Teledyne Brown Engineering and Kirk Dorius, an intellectual property attorney and mechanical engineer. The name “Flibe” comes from FLiBe, a Fluoride salt of Lithium and Beryllium, used in LFTRs. Flibe Energy Incorporated is registered in the State of Delaware.

Just like when wind turbine manufacturers talk of the superiority of wind as an energy source, especially as to how their turbines are better, I think Mr. Sorensen may be slightly biased in his opinion.

Sorensen estimates that it will cost “several hundred million dollars” to get to the first LFTR, but he is “confident that we will be able to garner sufficient funding to have a prototype thorium reactor in operation” by 2016.
…
In order to timely achieve its goals, Flibe Energy intends to work with the US Armed Services, which each have independent nuclear regulatory authority. Accelerated military development and demonstration can speed later deployment for civilian power production by providing extended materials and operational data to inform civilian reactor licensing through the Nuclear Regulatory Commission (NRC). (…)

Keep sending money and you’ll eventually get your “small modular” LFTR.
But they’ll be working with the US military, which is facing massive budget cutbacks thus funding from them will likely be constrained. The theory is the military would like to have self-sufficient on-base power generation. But naturally they’d be less than thrilled by the spewing of radioactive materials and hot molten salts after a missile or mortar strike. If this is really an issue the military can’t address with a diesel generator, as they’d always have the fuel on hand for their vehicles, long-lived Radioisotope thermoelectric generators (RTG’s) have been used for many decades, in space probes, the Soviets used them in unmanned lighthouses. The US Air Force uses them now for remote radar facilities. Very robust and rugged, portable, no maintenance.
And because they’re working with the military, I guesstimate it won’t be until 2020 when they can begin the process of getting a commercial-use reactor approved, provided their proposed development timeline goes smoothly. Even then, expect about two decades from now until they’re deployed, with regulatory approvals and permit approvals and inevitable lawsuits to wade through.
Meanwhile, thorium can be used in CANDU reactors now. It’s been looked at for decades. Here’s a 2000 paper, The Evolution of CANDU Fuel Cycles and Their Potential Contribution to World Peace.

There has long been an attraction for fuel cycles using thorium as a thermal breeder of fissile material (U-233). Thorium is three times as abundant as uranium in the earth’s crust, and U-233 is valuable as a fissile material due to its high value of fission neutrons produced per thermal neutron absorbed (eta).
Existing CANDU reactors can operate on thorium fuel cycles, with comparable fuel-cycle costs to the natural-uranium cycle and with improved uranium utilization. While ultimate efficiency is achieved with a self-sufficient cycle that relies only on bred U-233, economical once-through thorium (OTT) cycles can greatly extend uranium resources.
Several options have been identified for the use of OTT in CANDU reactors (Milgram, 1984), and on-power refuelling is the key to successful exploitation of this material. Two general approaches have emerged: the “mixed-core” approach, and the “mixed-fuel-bundle” approach (Boczar, 1998).
…
Thorium fuel cycles have additional benefits beyond uranium resource extension. Both the thermal conductivity and melting point of thorium oxide are higher than that of uranium oxide (by 50% and 340ºC, respectively). Thorium oxide is chemically very stable, does not oxidize, and creates fewer minor actinides than uranium. Even with the existence of economical uranium fuel cycles, thorium can be used to simultaneously extend resources and create a “mine” of safeguarded U-233 for future exploitation.

So we can start burning thorium now in CANDU’s, and economically, or wait until that great glorious day when LFTR’s are deployed. From the timescales I’m reading, they’ll arrive just in time to be quickly superseded by fusion reactors.
Besides, what do you get with a LFTR? A thorium-only reactor. With CANDU, you have a vast range of potential fuels, use what’s locally abundant and cheap.

The warmist/green/socialist lunatics (theyve all merged into an indistiguishable blob) dont want cheap, clean or even free energy becoming available because it dosnt fit in with their aims.
If a source of energy became available tomorrow to pull millions of starving africans out of the poverty their millions of kids get born into, the population would just continue to spiral massively upwards, the warmist aim is population reduction not expansion which is why theyre all for subsidies on dis-turbines and other “green” ideologies that keep people in poverty and push others into it.
As for teaming up with the likes of manny and hansen their sums dont add up anyways so anything theyre involved in is bound to fail.

Charles.U.Farley says:
June 8, 2012 at 2:49 pm
The warmist/green/socialist lunatics (theyve all merged into an indistiguishable blob) dont want cheap, clean or even free energy becoming available because it dosnt fit in with their aims.
If a source of energy became available tomorrow to pull millions of starving africans out of the poverty their millions of kids get born into, the population would just continue to spiral massively upwards, the warmist aim is population reduction not expansion which is why theyre all for subsidies on dis-turbines and other “green” ideologies that keep people in poverty and push others into it…..
________________________________
Unfortunately you and the Greenies are incorrect. The most effective birth control is a high standard of living. The USA, British Common wealth nations and the EU all have birth rates near or below replacement. It is poverty and especially subsistence farming (Kids are free labor) that promote breeding like rabbits.
BTW I have all the links to back that up if you want them.

kadaka (KD Knoebel) says:
June 8, 2012 at 2:50 pm
…CANDU’s burn spent fuel from light water reactors. We have decades of electricity from used fuel rods on hand, that people are wanting to throw down a deep hole for thousands of years. And CANDU’s are very efficient. See this paper I linked to last post….
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Thanks for the info. It is nice to know there is more than one option. I find it rather interesting this is the first I have heard of CANDU. Canada’s well kept secret? The MSM is only interested in denouncing nuclear and not reporting information.
If I recall correctly GE is the company providing fuel rods to US nuclear plants and owns a large stake (49%) of NBCUniversal. GE’s CEO Jeffrey Immelt, head of Obama’s “Jobs Council”, is moving even more GE infrastructure to China. GE makes more medical-imaging machines than anyone else in the world, and now GE has announced that it “is moving the headquarters of its 115-year-old X-ray business to Beijing”. Apparently, this is all part of a “plan to invest about $2 billion across China” over the next few years. But moving core pieces of its business overseas is nothing new for GE…. GE has shed 34,000 jobs in the U.S., according to its most recent annual filing with the Securities and Exchange Commission. But it’s added 25,000 jobs overseas…

The comments about the improved safety of the molten salt designs do not include detailed discussions about the removal of the decay heat. Decay heat is one of the two unique characteristics of nuclear plants that raises safety concerns. You have to continue to remove decay heat from the nuclear reaction in order to prevent the release of fission products, which is the other unique characteristic. Fossil fuel plants shut off the fuel (coal, oil, gas) supply, and the machine just cools down. When you shutdown a nuclear plant, you can stop the fissioning quickly, but you are still left with the fission products that continue to decay and release significant amounts of energy for a significant amount of time. The safety systems are designed to make sure that you can continue to remove the decay heat.
Molten salt reactors will be creating the same amount of fission products per unit of energy generated as nuclear plants that use discrete fuel elements. 1000 MW of molten salt capacity will create the same amount of waste/FPs as 1000MW of LWR capacity or PBR or FBR. Those FPs must continue to be cooled, until they are placed into a condition that does not threaten their containment. If you “dump the molten salt into ciriticality-safe tanks” you stop the fission process, but you still have the FPs and their decay heat to deal with. If you cannot cool the tanks, they will melt, and you will lose containment of the FPs. Designing the tanks to be cooled passively is not simple. Gas coooled reactor supporters like to say that their fuel can maintain integrity without active cooling, and they have some calculations and experimental data to back them up. However, in real life there are a LOT of “interesting” scenarios that can challenge the integrity of their FP containments.
None of the nuclear generating options is absolutely safe. The technology has the inherent risk associated with containing FPs. However, I would point out that several hundred people died in Japan when the trains they were on were swamped by the tsunami. No one has really been injured by the Fukushima accident. People have very different ideas about acceptable levels of risk from different technologies that are not amenable to rational analysis or argument.

Bernd Felsche says:
June 8, 2012 at 10:30 pm
@kadaka:
Look up “positive void coefficient”. Then Chernobyl. Then CANDU.
You don’t need graphite for a reactor to become unstable.
CANDU requires active control system response to maintain stability.
If you let a molten-salt reactor “over-heat”, the freeze plug melts and the salts drain under gravity into passively-cooled tanks.

Yes theoretical void coefficient de-rates CANDU’s output slightly, however since light water is a poison to the CANDU fission flux, ordinary untreated water may be used for emergency core cooling, with no need for additional poison addition (neutron absorbing chemical ie boron). This means they can never run out of emergency coolant.

“If you let a molten-salt reactor “over-heat”, the freeze plug melts and the salts drain under gravity into passively-cooled tanks.”

Older CANDUs employed the same dump technique only the reactor simply dumped the entire moderator (D2O), stopping any and all fission. It is not unique to the molten salt technology. GK

Seems we have both a Steve Piet and Steve P!
In comparing options, one has to look at what advocates say and especially what they don’t say; and what the market does. CANDUs with heavy water coolant and heavy water moderator do not need uranium enrichment. The “burnup” is about 7 MWth-day/kg-iHM (energy per kg of initial uranium) and one kg of uranium in ore turns into 1 kg of uranium in fuel. Pressurized and boiling water reactors are now getting about 50 MWth-day/kg-iHM and it takes approx 8 kg of uranium in ore to make one kg of uranium in fuel (via enrichment). So, in terms of thermal power/kg of uranium in ore, CANDUs are slightly more efficient. But, CANDUs get somewhat lower thermal efficiency, so CANDUs and PWR/BWR are about the same in terms of electricity/kg of uranium ore. But, all extract <1% of the energy in the original uranium. To get 80-99% energy extraction, one must recycle in a breeder reactor, but those are politically incorrect. Same result with thorium. Whether U/Pu239 or Th/U233 fuel cycles, if you want to really maximize energy and minimize waste, you recycle used fuel. The political greens will oppose either U/Pu239 or Th/U233 because it means nuclear would have minimal waste & would be more sustainable.
But, the market …. The Canadian's own new and improved concept has heavy water moderator but light water coolant to improve economics. This allows them to get 20 MWth-day/kg burnup but requires some uranium enrichment. Why the change? higher thermal efficiency. less trouble with tritium created in the heavy water coolant leaking to the environment. less cost of making heavy water for the coolant.
Another factor, if I am going to recycle any of those fuels, it makes the most sense to recycle one one with the most residual good stuff. Used PWR/BWR fuel has ~1% Pu. Used CANDU fuel has much less. So, to get the most recovered usable material per dollar spent, one would recycle PWR/BWR fuel, not CANDU fuel.

One last comment. Some people have alluded to the differences of opinion between Alvin Weinberg and Hymen Rickover. I don’t think they really understand the roles of these two people in the history of nuclear energy. Weinberg was a scientist, and a visionary. He came up with the idea for a water-cooled reactor, the PWR, that was chosen by Rickover for the nuclear navy. I believe that he also had a lot of other very innovative ideas about different types of reactors. He never had to actually develop these designs into working machines that made practical, economical power. He was a researcher.
Rickover was an engineer. He had to come up with a design that would fit into a tube less than 50 ft wide, and would make reliable power independent of support facilities, while people were shooting at the tube holding the reactor. All without injuring the operators who lived inside the tube with the reactor. Rickover also was responsible for developing the only truly workable thorium fuel that was tested successfully at Shippingport. Weinberg had the idea, while Rickover had to make it work.
The biggest problem with thorium is that there is no need for it because the cost of uranium is so low. As a percent of the cost of generating power, the cost of the raw material for the fuel is trivial. We could extract uranium from seawater and never significantly affect the cost of electricity generated by LWRs. With the availability of U from seawater, there is no need to use anything else, not even Pu. Thorium, on the other hand, would require the creation of an entirely new infrastructure for fuel manufacture, transport, storage, etc, which no one wants to pay for.

rxc6422 says:
June 9, 2012 at 11:08 am

Oh, and implementation of the precautionary principle basically amounts to giving control of your society to the people who tell the scariest stories. Not the way I want to be governed.

But it’s what you’ve got. I don’t know if putting the smartest people in charge is the answer, but we’re a long way from that anyway, with a succession of slick, wealthy, ruthless types seemingly at the controls, and all doing their best to keep the hoi polloi scared witless with a never-ending stream of bogie-men.
rxc6422 says:
June 9, 2012 at 10:31 am
You addressed only the first part of my second point, and my first point not at all.
In view of the fact that the situation at Fukushima has not been resolved, and accurate reporting hard to come by, I suggest it’s a wee bit early to know what the final reckoning will be, your breezy dismissal of any possible medical problems notwithstanding.
Of course we are bathed in natural background radiation, but that doesn’t address the question I raised about “increasing radiation exposure” above and beyond that, .