The Nuclear Power Thread

[OmCheeto]

Neglecting losses, which I think you underestimate, other problems: Cost between one and two million USD per mile...

hmmmm...

https://en.wikipedia.org/wiki/Pacific_DC_Intertie
Pacific DC Intertie
600,000 $/day savings because of the intertie [wiki]
219,145,320 $/year savings [maths]
846 miles length [wiki]
2,000,000 $/mile [gmax137]
1,692,000,000 $ construction cost [maths]
7.721 years payback [maths]​

7.7 years sounds like a reasonable payback time for a large project.

http://www.eia.gov/todayinenergy/detail.php?id=15131
2013
268,000,000,000 $/yr net crude oil imports [eia]
734,000,000 $/day net crude oil imports [maths]
1,692,000,000 $/project construction cost of 846 mile DC intertie [maths]
2.3 equivalent days of crude oil imports to pay for construction of the Pacific DC Intertie [maths]​

2.3 days... Wow.
Your monetary argument therefore strikes me as silly.
As do your other two arguments, which are, IMHO, not even worth discussing.

--------------

But, getting somewhat more back on topic...
I watched a video the other day, where a professor was discussing Thorium reactors. I thought it was very interesting

Thorium (new) - Periodic Table of Videos

Published on Mar 21, 2016
Thorium, element 90 on the periodic table.​

Professor Sir Martyn Poliakoff:

@7:41; "I suspect that if nuclear power had been started for civilian use that the cost would have been prohibitive and people might never have used nuclear power"

@8:19;"...it would be much more feasible now to go on to the thorium cycle than it would have been in the nineteen forties."​

 

[Astronuc]

Astro - I believe this so called industry status report is written by anti-nuclear activists.

http://www.worldnuclearreport.org/Who-We-Are.html

I wouldn't say they are anti-nuclear activists, as much as they are in energy policy and research. Several seem to have had involvement in the nuclear fuel cycle area. They are certainly critical of nuclear energy, and reasonably so. As anorlunda, the data on startups and closures are readily available, and anyone contemplating going into nuclear energy should be aware of the situation and the bigger picture regarding energy and infrastructure policy.

As for long transmission lines, one can find those across the US, particularly in the west. Power can be 'wheeled' across the nation, but that is usually balanced with regional generation, much like putting water in at one end of a long lake (or river) and extracting at the other end. One can find plenty of transmission lines associated with hydro and wind generation along the Columbia river - both in Washington and Oregon, and some of that goes to California.

Regarding hydropower in the US, if anything, there is a movement to reduce the number of dams on some river systems. One goal is the revival of fishing resources.

Some perspective on NW US energy generation and exchange with California. (See pages 2-9 (bottom) through 2-11)
https://www.nwcouncil.org/media/7149936/7thplanfinal_chap02_stateofthesystem.pdf

 

[mheslep]

Neglecting losses, which I think you underestimate, other problems: Cost between one and two million USD per mile, theft of private property under "eminent domain," degraded visual landscape...

The most recently completed HVDC project in N. America had cost $6 million per GW mile (eastern Alberta). I referenced transmission above in the Chinese case because they are building hydro in the west with long transmission runs, which could double the total cost of a dam project, something to consider when weighing against new nuclear power.

 

[mheslep]

I wouldn't say they are anti-nuclear activists, as much as they are in energy policy and research. Several seem to have had involvement in the nuclear fuel cycle area.

When I review this and past Status Reports, I find the lead authors are Mycle Schneider and Antony Froggatt, and have been for years. Per his bio, Froggatt has no degree in hard science or engineering. For twenty years, Schneider (see 'about the author' here) was an executive director of WISE, with slogan "imagine a world without nuclear power". The 2015 Status Report was supported by the http://NRDC , the Swiss Renewable Energy Foundation, then the Greens-EFA from the EU. The Status Report in 2013 featured a forward from the avidly anti-nuclear Amory Lovins (2010), and in past years was commissioned by the Greens-EFA group in Europe (2004 & 2007), the anti-nuclear German Federal Ministry of Environment (2009)

They are certainly critical of nuclear energy, and reasonably so. As anorlunda, the data on startups and closures are readily available, and anyone contemplating going into nuclear energy should be aware of the situation and the bigger picture regarding energy and infrastructure policy.

There are 58-60 reactors currently under construction across 14 countries. With average power 1 GW/ reactor, they'll produce 480 TWh/yr of emissions-free power at the plant. A couple weeks ago the US NRC licensed another new 2-reactor plant in S. Carolina. Granted the industry has its problems, like the pending closure of Diablo, but why should an objective view necessarily be "critical"?

As for long transmission lines, one can find those across the US, particularly in the west. Power can be 'wheeled' across the nation, but that is usually balanced with regional generation, much like putting water in at one end of a long lake (or river) and extracting at the other end. One can find plenty of transmission lines associated with hydro and wind generation along the Columbia river - both in Washington and Oregon, and some of that goes to California.

Yes long distance transmission exists in the US and elsewhere. However, new land based transmission proposals in the US are also sometimes rejected after many years, even decades, before acquiring interstate right of way, and the most recently completed HVDC project in N. America ( across sparsely populated Alberta) had cost $6 million per GW-mile. At that price, replacing one of the pending east coast nuclear plants (2.2GW) with, say, Midwest power across a 1000 miles has cost $13B. Shipping intermittent power through those lines equivalent to the average output of a nuclear plant makes them still more problematic

Regarding hydropower in the US, if anything, there is a movement to reduce the number of dams on some river systems. One goal is the revival of fishing resources.

Agreed. It is unlikely that hydro power capacity will expand in the developed world. And, given hydro is by far the dominate share of 'renewable' power, when Status Report touts large renewable figures as trending, when hydro expansion has the limits you describe, I believe they are being deceptive.

 

[Delta Force]

Agreed. It is unlikely that hydro power capacity will expand in the developed world. And, given hydro is by far the dominate share of 'renewable' power, when Status Report touts large renewable figures as trending, when hydro expansion has the limits you describe, I believe they are being deceptive.

It's worth noting that hydropower and natural gas are the only two technologies capable of integrating the more variable forms of renewable energy into a power grid. If hydropower and nuclear energy aren't able to maintain their current contributions that does provide an opening for new power sources in the United States electricity market, which has been stagnant for many years (growth in natural gas and renewable generation is largely zero sum and associated with declines in coal). The question is what will fill that gap, renewable power or natural gas, or more precisely at what ratio, because renewable power systems still need integrating power and still need firm power.

 

[anorlunda]

It's worth noting that hydropower and natural gas are the only two technologies capable of integrating the more variable forms of renewable energy into a power grid. If hydropower and nuclear energy aren't able to maintain their current contributions that does provide an opening for new power sources in the United States electricity market, which has been stagnant for many years (growth in natural gas and renewable generation is largely zero sum and associated with declines in coal). The question is what will fill that gap, renewable power or natural gas, or more precisely at what ratio, because renewable power systems still need integrating power and still need firm power.

Future behavior of that ratio is as unknowable as future prices on the stock market. The reasons why are largely the same as for the stock market. It is a collective result of many individual economic and political decisions. You posted your question on an engineering forum, but engineering considerations only pay a minor role.

Are you interested in energy futures trading?

 

[Delta Force]

Future behavior of that ratio is as unknowable as future prices on the stock market. The reasons why are largely the same as for the stock market. It is a collective result of many individual economic and political decisions. You posted your question on an engineering forum, but engineering considerations only pay a minor role.

Are you interested in energy futures trading?

I'm giving a landscape level view of things, the next decade or two will certainly be interesting for nuclear power in the energy portfolio of the United States and many other early adopters. I'm not sure if that's something anyone would be interested in here, since it isn't exactly engineering of course.

I should mention that I'm trained in energy policy, not engineering or physics. Political decision-making is definitely one of the factors that goes into the economics of energy, but engineering still plays a major role.

 

[anorlunda]

Political decision-making is definitely one of the factors that goes into the economics of energy, but engineering still plays a major role

In a deregulated world, politicians and engineers can write all the energy plans they want, but who will follow those plans?

Imagine calling some wind power developers to say, "Our energy plan calls for more gas generation at that location, not wind. Please build a natural gas plant instead of wind.". That is no longer the way things work in the real world. Independent developers of wind, solar or fossil don't take orders. Government can create incentives and hurdles, but it can't issue orders.

 

[etudiant]

In a deregulated world, politicians and engineers can write all the energy plans they want, but who will follow those plans?

Imagine calling some wind power developers to say, "Our energy plan calls for more gas generation at that location, not wind. Please build a natural gas plant instead of wind.". That is no longer the way things work in the real world. Independent developers of wind, solar or fossil don't take orders. Government can create incentives and hurdles, but it can't issue orders.

I think that underestimates the many levers of influence the government wields in practice.
Wind energy for instance can be crippled in the US simply by enforcing the Endangered Species Act, which permits large scale 'takings' of endangered large raptors such as the Golden Eagle. Similar methods could shut down solar or fossil fuel plants, there are many regulations available to halt developments.
The obverse is that it is very difficult to get the private sector to do the things government would like just by incentives and hurdles. Private enterprise will always find a way to thread the regulatory needle to optimum effect, which may be quite different from the ideas of the regulators.

 

[wizwom]

In a deregulated world, politicians and engineers can write all the energy plans they want, but who will follow those plans?

Without regulation, the Engineers planning would be the power company engineers, and their company would follow the plan. They would buy what power they wanted when they chose to, and otherwise protect their interests and arrange for the stability of their grid.
If they are ASKED what they want by a producer, they will gladly share their estimates. You know... everyone doing things voluntarily, because no one has guns involved.

Imagine calling some wind power developers to say, "Our energy plan calls for more gas generation at that location, not wind. Please build a natural gas plant instead of wind.". That is no longer the way things work in the real world. Independent developers of wind, solar or fossil don't take orders. Government can create incentives and hurdles, but it can't issue orders.

They would not say to a wind farm "our plan calls for such and so" - they would merely buy or not from the farm as they need and the farm produces. And if the farm cannot run stably (which is typical) then they would put in their own stable power, and not buy the wind power. because, you knoiw, they have the power needs covered already, thanks.
So, if the wind farm reworks to have instant-on gas (at their own expense) and can meet the stability needs, then they can start selling again. Or they can hope.
Similar with solar.
I suspect in such a regime, wind would power local or remote pumped hydro, which would sell the actual power to the grid; the mass wind would never hook up to the grid. Solar might be hoooked up, especially in the summer, since it ramps up somewhat in line with AC need.
But in such a system nuclear would far and away conquer baseload power.

 

[jim hardy]

A complete non-sequitur, but i just stumbled across this video , a tour of EBR-1 by an old timer. Five part series.

 

[OmCheeto]

A complete non-sequitur, but i just stumbled across this video , a tour of EBR-1 by an old timer. Five part series.

1:35 "After it melted down"

The good old days.

ps. I did my nuke training at the S1W prototype, which came on line just 2 years later.
pps. I don't remember the EBR-1, so thank you for the video.
Wiki, regarding the EBR-1; "At 1:50 p.m. on December 20, 1951, it became one of the world's first electricity-generating nuclear power plants when it produced sufficient electricity to illuminate four 200-watt light bulbs."
Wiki, regarding the S1W prototype facility; "The S1W reactor reached criticality on March 30, 1953." ... "S1W was shut down permanently in 1989 (October 17)"
I was there around 1979.
ppps. On a really silly side note, my girlfriend at the time bought me a radium dial wristwatch, which I had to remember to not take to school, as I did take it to school one day, and discovered it was very radioactive. (2 or 3 times over background. But don't quote me on that, as that was a long time ago)
My nightmare:

Radiation Nazis; "Petty Officer Om, your watch is contaminated, and will have to be confiscated, encased in cement, and buried."
Young Om; "Nooooo! My girlfriend will kill me!"​

 

[mheslep]

Cuomo is closing Indian Point in 2020 (2GW, dual unit) years ahead of schedule, replacing it with natural gas. I'm not sure why anyone in NY would take the need for clean power seriously after closing 20% of the state's clean power.

 

[Astronuc]

For those interested in nuclear fuel,

http://www-pub.iaea.org/books/IAEABooks/Subject_Areas/0802/Fuel-fabrication-and-performance

Nuclear reactors and power plants

http://www-pub.iaea.org/books/IAEABooks/Subject_Areas/0603/Nuclear-power-plantsSome historical information on the state-of-the-art in NPPs and nuclear fuel in the US ca. 1976
http://www.osti.gov/scitech/servlets/purl/7343952
by HS Cheng, Operational Limitations of Light Water Reactors Relating to Fuel Performance*, BNL-NUREG-21459, Brookhaven National Laboratory, 1976.

 

[Jon Richfield]

There is at least one major unsolved problem with nuclear power. What do you do with the spent fuel? Right now it just accumulates at the various plant sites. Yucca mountain is still iffy as a long term solution.

I don't believe the waste problem is worth worrying about as long as there is reasonable responsibility. Granted, people are not always responsible -- ask them at Hanford, and what was that place? Ch- something something? But if we never do anything till no one is irresponsible for nothing, that is what we will achieve... nothing.

And nothing is REALLY expensive in many currencies... including human effectiveness and dignity.

High level waste is so small in volume that it is easy to watch till it is wanted. Low level and medium level waste can reasonably readily be stored till it its short halflife material has reduced to convenient levels, then concentrated till it too is a smaller in volume and more active, then either used for whatever is useful, or burnt in a high neutron flux to dispose of troublesome isotopes, and that is that.

Cheap?

No, but not forbiddingly costly and a LOT cheaper than vitrification or burial etc.

Something about nukes makes a lot of folks who should know better nur around like chickenless heads.

 

[wizwom]

I don't believe the waste problem is worth worrying about as long as there is reasonable responsibility. Granted, people are not always responsible -- ask them at Hanford, and what was that place? Ch- something something? But if we never do anything till no one is irresponsible for nothing, that is what we will achieve... nothing..

Oh, Hanford was a mess... but it was also _evil_.
The specifically released radiation to see the effect on the populace without consent or warning.

 

[Jon Richfield]

Oh, Hanford was a mess... but it was also _evil_.
The specifically released radiation to see the effect on the populace without consent or warning.

I tend to be cynical about the good faith of those in power, and I agree that the negligence and CYAsserie of the Hanford authorities was criminal (really criminal, not just naughty-naughty, but grounds for shooting a few representative examples in public) but the way you put it sounds to me like conspiracy theory. As stated, I disbelieve it.
Suit yourself of course...

 

[Astronuc]

http://www.world-nuclear-news.org/NN-Terrestrial-Energy-unveils-SMR-licensing-plans-24011701.html

Terrestrial Energy USA announced today it had informed the US Nuclear Regulatory Commission (NRC) of its plans to license a small modular reactor (SMR) in the USA. Terrestrial said it intends to start "pre-application interactions" with the regulator this year and to make its licensing application in late 2019.

http://terrestrialenergy.com/terres...r-regulatory-commission-imsr-licensing-plans/

Terrestrial Energy USA Ltd Response to NRC Regulatory Issue Summary 2016-08
https://www.nrc.gov/docs/ML1633/ML16336A508.pdf

 

[mheslep]

http://www.world-nuclear-news.org/NN-Terrestrial-Energy-unveils-SMR-licensing-plans-24011701.htmlhttp://terrestrialenergy.com/terres...r-regulatory-commission-imsr-licensing-plans/

Terrestrial Energy USA Ltd Response to NRC Regulatory Issue Summary 2016-08
https://www.nrc.gov/docs/ML1633/ML16336A508.pdf

I can't see a practical way forward for Terrestrial and it's limited finances under the current US regulatory environment. Bill Gates' Terrapower was refused a prototype in the US; they were forced to China.

 

[Astronuc]

Bill Gates' Terrapower was refused a prototype in the US; they were forced to China.

The current regulatory structure evolved out of the accident at TMI, and I think it's reasonable given the way it was done before TMI.

An event at the Enrico Fermi Nuclear Generating Station kind of dampened enthusiasm for commercial fast reactors.
"On October 5, 1966, Fermi 1, a prototype fast breeder reactor, suffered a partial fuel meltdown, although no radioactive material was released. After repairs it was shut down by 1972." Source: https://en.wikipedia.org/wiki/Enrico_Fermi_Nuclear_Generating_Station
https://www.nrc.gov/info-finder/dec...r/enrico-fermi-atomic-power-plant-unit-1.html

The US is not about to allow someone to build a prototype reactor without some testing, and unfortunately, the US shutdown FFTF (in 1992) and then EBR-II (in 1994), which were the only two fast reactors operating in the US. FFTF was a 400 MWt plant, and in theory, it could be restarted. Congress is not too enthusiastic about spending tax dollars on a commercial fast reactor, and the NRC is not about to approve any reactor concept without appropriate demonstration of the concept.

We've discussed the TWR concept here at PF. It was problematic as originally envision, and subsequently, Terrapower's concept is basically a conventional fast reactor. They have some smart folks, but little experience with fast reactors.

Terrapower went to China because they have an operating fast reactor.
http://www.world-nuclear-news.org/NN-Chinese-fast-reactor-completes-full-power-test-run-1912144.html
http://www.nti.org/learn/facilities/784/

Some background on Fast Reactor Technology
https://www.iaea.org/NuclearPower/FR/

Some history of fast reactors in the US
http://scienceandglobalsecurity.org/archive/sgs17cochran.pdf
http://www.hanford.gov/page.cfm/400AreaFFTF

In my professional experience, I've been to both TMI and Fermi plant sites to work with the respective utilities on matters related to fuel performance.

 

[nikkkom]

Low level and medium level waste can reasonably readily be stored till it its short halflife material has reduced to convenient levels

Can be untrue depending on nuclides in question. If, say, low-level waste is a result of Pu contamination, "its halflife" is many thousands of years.

 

[Jon Richfield]

Please note what I said: "Low level and medium level waste can reasonably readily be stored till it its short halflife material has reduced to convenient levels". Granting that some Pu isotopes have short halflives, those that do NOT have short halflives are not "short halflife material".
Or have I missed something? Yet again? As on occasion I do?

 

[mheslep]

Thanks for the response Astronuc.

The current regulatory structure evolved out of the accident at TMI, and I think it's reasonable given the way it was done before TMI.

I agree the TMI accident indicated a need for regulatory change; IIRC, operator training in particular was improved. That is not same as showing the regulatory structure in place today is reasonable, that (for instance) LNT and ALARA is valid. An application for an already accepted technology (light water), never mind any construction, is what, a billion dollars and four years? And the application may still be rejected.

An event at the Enrico Fermi Nuclear Generating Station kind of dampened enthusiasm for commercial fast reactors.
"On October 5, 1966, Fermi 1,

As you indicate, the Fermi 1 accident was fifty years ago. There were also some 1800 deaths from aviation accidents that year, though I don't know that these damped enthusiasm for aviation. Per the Wiki, following shutdown and repairs (from 1% fuel melt), the reactor was restarted and returned to full power in 1970.

...US is not about to allow someone to build a prototype reactor without some testing,

Yet the US government did in fact allow Detroit Edison to build a prototype fast reactor. How is testing and validation to be obtained, if not with some kind of demonstration or prototype facility? The US has years of data on generic fast reactors. What's required now is a test/demonstration/prototype of the proposed design.

Congress is not too enthusiastic about spending tax dollars on a commercial fast reactor, and the NRC is not about to approve any reactor concept without appropriate demonstration of the concept.

Why must Congress fund a fast reactor, as opposed to directing the NRC to oversee the construction of one funded by private industry?

We've discussed the TWR concept here at PF. It was problematic as originally envision,

Yes. Also, large pressure/boiling water reactors can be said to be problematic. See, e.g., expensive secondary containment, LOCAs, and Fukushima. The issue then is one of relative safety and cost.

Terrapower went to China because they have an operating fast reactor.

Several countries have fast reactors: China, Russia, India, as did the US in the past as you indicate. However, I've not see where Terrapower indicated they went to China because China had a traditional fast reactor, which would not necessarily validate Terrapower's design. The agreement between China's CNNC and Terrapower enables the construction of a 600 MWe TWR (travelling wave) in China starting in 2018, and a larger plant in the 2020's. With regard to problems with building the reactor in the US, I have seen these quotes:
Nathan Myrhvold, Transatomic reactor patent holder:

"I don't think the U.S. has the willpower or desire to build new kinds of nuclear reactors," Mr. Myrhvold says. "Right now there's a long, drawn-out process."

 

[etudiant]

Thank you, mheslep, for that excellent reference.
I had not known that there was such a plethora of promising reactor designs.
It is a tragedy that this industry has so completely failed to recognize that public acceptance is just as critical as technological effectiveness for success.
That failure remains ongoing, as demonstrated recently by the New Mexico WIPP accident and its subsequent handling.
As of now, consequently, Nathan Myrvold's perspective seems entirely correct and the US is gradually falling off the pace in nuclear technology.
Russia and China appear to be the only polities which still support innovative reactor designs. Has to be very discouraging for those who have labored all their professional lives in this sector.

 

[Astronuc]

The agreement between China's CNNC and Terrapower enables the construction of a 600 MWe TWR (travelling wave) in China starting in 2018, and a larger plant in the 2020's.

From the World Nuclear article on the TWR, it seems Terrapower has substantially changed the design, as was expected, to a more conventional FR design, which is now described as a Standing Wave Reactor.

However, by mid-2011 TerraPower changed the design to be a standing wave reactor, since too many neutrons would be lost behind the traveling wave of the previous design and it would not be practical to remove the heat efficiently – the cooling system could not follow the wave. A standing wave design would start the fission reaction in a small section of fuel enriched to 12% at the centre of the reactor core, where the breeding wave stays, and operators would move fresh fuel assemblies from the outer edge of the core progressively to the wave region to catch neutrons, while shuffling spent fuel out of the centre to the periphery. As the wave would be surrounded by new fuel in most directions, more neutrons would be utilized compared with a traveling wave scheme. The “shuffling” would be conducted while the reactor is operating. Such a reactor could reach a fuel burn-up of “up to 30%” and run 30 to 40 years without refueling, according to TerraPower. It would still use sodium as coolant.

The concept still needs to be demonstrated. A burnup of 20% is reasonable, if proper design is taken into account. That 20% means a 20% increase in volume, which has to be accommodated somewhere in the design. Up to 30% means a 30% increase in volume, and there needs to be some accommodation of the fission gases in the fuel and in whatever void volume is provided, or generated during operation. They'll have to address fuel swelling. One also has be careful with burnup and fluence gradients, which can induced differential growth and structural distortion.

Building reactors and power plants is quite different from developing consumer products and software, typically on the order of developing a new aircraft. Most technology companies are averse to big R&D budgets, hence the government role in financing new reactor designs and NPPs.

I'm guessing TWR-P is the prototype(P) design and TWR-C is the commercial (C) design. It might be years out from startup before the concept is fully demonstrated.

Some comments in the WSJ article are problematic, e.g.,

Another plus: Large supplies of depleted uranium are available as a byproduct of today's water-cooled reactors. Removing it from those reactors and reprocessing it for reuse is a costly procedure, and a source of worry that radioactive material might fall into the wrong hands. Reducing the need for reprocessing could save money and reduce the risk of nuclear proliferation.

Depleted U (DU) is a by-product of the enrichment process, before the fuel (in fuel assemblies) is fabricated. DU is not removed from spent fuel, although the U is reduced in U-235, while isotopes of Np, Pu, Am, Cm are produced. Recovering U and the TU isotopes requires reprocessing, which is more expensive than producing straight enriched-U fuel.

 

[mheslep]

...Russia and China appear to be the only polities which still support innovative reactor designs. Has to be very discouraging for those who have labored all their professional lives in this sector.

Professor of Chemical Engineering, Nuclear Engineering, and Medical Doctor Eric McFarland mentions in a talk that he advises some of these nuclear startups, and that he suggests they to go to Argentina, as he belives the country is friendly to new designs.

 

[etudiant]

I fear the good professor is not well acquainted with the real world.
Argentina has been receptive to innovative nuclear designs since the days of Juan Peron, sadly without the needed skepticism essential to distinguish between fantasy and feasibility. In addition, the record of Argentina in terms of industrial projects is considerably weaker than Brazils. The base for implementing anything is not there.

 

[Astronuc]

Terrapower has a number of published technical papers/reports available online.
http://terrapower.com/uploads/docs/ICAPP_2011_Paper_11199.pdf

A good overview of Terrapower from IANS Meeting, Idaho Falls, Idaho, March 21, 2013
http://www.uxc.com/smr/Library\Design Specific/TWR/Presentations/2013 - TerraPower and the TWR.pdf

https://www.uxc.com/smr/uxc_SMRDetail.aspx?key=TWR

UxC's SMR profile page: https://www.uxc.com/smr/uxc_SMRDetail.aspx (apparently mPower is the default, but the drop down menu gives a list of all the SMR projects)

 

[mheslep]

Oak Ridge recently released a validation of the Transatomic MSR fast-thermal hybrid design:
From the ORNL report:

...Previous work has shown that the TAP design outperforms traditional LWRs in waste metrics, with the TAP design generating 53–83% less actinide waste per megawatt generated. With fueling scenarios 1 and 2 [5% LEU], the TAP reactor achieves a burnup of over 80 GWd/MTU and a waste reduction of 53%. With fueling scenario 3 [20% LEU], the TAP reactor achieves a burnup of over 200 GWd/MTU and a waste reduction of 83%. A typical LWR achieves a burnup of 45 GWd/MTU with enrichments of up to 5%.

http://info.ornl.gov/sites/publications/files/Pub72176.pdf

https://www.nei.org/News-Media/News/News-Archives/ORNL-Verifies-Performance-of-Transatomic-s-Advance

Transatomic has PR statements out that they are now focused on establishing long term survival of its reactor vessel in the presence of the high temperature salt and neutronics, ie for decades. I wonder if the search for the perfect, lon lasting metal alloy for a salt tank is misguided. The chemical industry apparently has long settled on the solution of a 'freeze wall' of solid salt to act as a long term barrier between container (ceramic or metal) and corrosive molten salt. I would think a solid salt wall would also solve the problem of (radiation induced) free fluorine corrosion of the vessel.

It may be that a freeze wall works in a scenario where operation is just above the melting point, whereas the reactor will operate at a much higher temperature for reasons of thermodynamic effciency, thus forcing a longer path to the outise freeze shell, and thus a larger vessel, else the entire salt load melts.

The Transatomic design, with no water cooling in the primary loop, and thus no primary steam, implies no need of enormous secondary containment in lieu of a pressure vessel breech. I imagine the economic success of MSRs depends on the US NRC letting go of that light water, high pressure concept.

 

[etudiant]

I'd suspect that the regulators will be loath to forego the added protection of a large secondary containment.
The world has changed and terrorism has become much more of an issue.
The accidents that are now credible can be externally induced and need to be factored in beforehand.

 

[mheslep]

I'd suspect that the regulators will be loath to forego the added protection of a large secondary containment.
The world has changed and terrorism has become much more of an issue.
The accidents that are now credible can be externally induced and need to be factored in beforehand.

If so then I expect the US nuclear regulators will slowly regulate themselves and the existing industry out of existence.

The size of secondary containment as originally conceived was related to the steam volume in the event of a pressure vessel breach. Insisting on rigorous security measures is one thing, but insisting on the same steam driven structures for an MSR would be incoherent.

I'm curious as to what worst case attack could be carried out against an MSR facility, if there is no possibility of a hydrogen explosion, and fission products are contained in the salt, rapidly turning to glass state.

 

[etudiant]

If so then I expect the US nuclear regulators will slowly regulate themselves and the existing industry out of existence.

.

Is that not a fair description of the current state of affairs for US nuclear?

Separately, it seems only logical to me that regulators take stock of the terrorism issue, We've seen a number of platoon sized assaults spearheaded by suicide bombers penetrating well guarded facilities in the past few years, nuclear plants surely must be seen as an attractive terror target.
I'd guess that ignorance might limit the damage the intruders could inflict, but someone skilled could surely steer a reactor into a disaster with external repercussions..

 

[OCR]

I'd suspect that the regulators will be loath to forego the added protection of a large secondary containment.

I'd suspect you're right, too... and, there's more than a little irony involved, when...

The accidents that are now credible can be externally induced...

A containment system would be needed as some form of external protection... sounds slightly oxymoronic.

 

[etudiant]

Iirc, the containment was always seen as a protection against external incidents, although in those days the concern was airplanes crashing into the reactor.
The advertised strength was that it would remain intact even if hit by a fully fuelled jetliner such as a 707.
Containment was probably another piece of industry 'safety speak', shorthand for the spec that 'mheslep' has outlined above.
It does not reflect the range of protections the structures were expected to provide.

 

[mheslep]

...
I'd guess that ignorance might limit the damage the intruders could inflict, but someone skilled could surely steer a reactor into a disaster with external repercussions..

As could be done with any major industrial facility. See, e.g., the petroleum train accident that destroyed half a town in Quebec. The relevant question is whether or not willful sabotage on a next gen MSR plant could do any more harm than the sabotage of, say, some large chemical factory or refinery. I can only speculate, but it seems to the answer is probably no without the possibility of steam or hydrogen explosions, especially if the facility is underground.