Energy From Thorium Discussion Forum

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PostPosted: Nov 18, 2016 10:17 pm 
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Saying it's too late to do anything is a counsel of desperation. We know that nuclear, of one brand or another, can replace stationary power sources. That still leaves industrial heat and transport, which should be getting far more research than they are.
Then, reducing emissions is not enough, we have to lower CO2 levels in the air ( and the oceans, which equilibrate to the air above them. ) That is possible, through enhanced weathering - R Schuiling estimates that bringing the biosphere back to pre-industrial CO2 levels would require grinding up a volume of olivine rock about equal to the island of Kauai, in Hawaii. Again, off-peak nuclear power would be the obvious energy source.
http://www.innovationconcepts.eu/res/li ... ange23.pdf
In the meantime, climate and sea level do not immediately move to match greenhouse gas levels, there is a delay. Otherwise, we'd already have sea levels 6 metres higher than now, as happened the last time CO2 was at 400 ppm, during the Eemian interglacial. That grace period can be extended by enhanced albedo techniques. This is already happening; sulphur emissions from coal burning are blunting the impact of greenhouse warming, just as the natural sulphur from the Pinatubo eruption in the nineties cooled the planet for several years.
Proposals for a fleet of cloud-seeding ships have also been made, to be powered by wind. Far more effective would be to simply repurpose the world's nuclear navies, currently deterring, or threatening, another form of self-inflicted extinction.
http://geo-engineering.blogspot.co.nz/2 ... eding.html
Steven Salter, the proposer of these Flettner rotor robot ships,also designed a wave power device, the Salter Duck, back in the seventies, and accused the United Kingdom's nuclear establishment of nobbling the development of his invention. Of course, wave power shares wind's obvious disadvantage of not always being there when and where you want it. In particular, the oceans around the equator, where solar heating is strongest and cloud albedo modification would be most effective, were known and hated in the days of sail as ' the Doldrums.' There are around a hundred operational nuclear powered submarines, of six countries' navies, that could deploy more power already afloat than Salter's proposed 1500 weather dependent robot vessels.


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PostPosted: Nov 19, 2016 1:10 am 
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E Ireland wrote:
Tim Meyer wrote:
Thanks, E, for the positive comment. HWRs are for natural uranium and not thorium. This is the energy from thorium forum. CANDUs are running and TMSRs have never been built beyond the ORNL MSRE.

The advantage of HWRs is that they can run on almost anything with relatively minor modifications - I had an email conversation with someone at CNL Chalk River about the possibilities for modifications to the CANDU to better enable a Thorium or mixed cycle. If necessary you could push uranium use way down and generate most of the enemy from thorium fission....


Here's a review written back in 1976 re thorium-burning CANDU-type reactors https://inis.iaea.org/search/search.asp ... RN:7258022

The bottom line is that isobreeding (of 233U) in CANDUs could indeed probably be achieved. However the cost would be pretty high because it would require the making/dissolution/reprocessing/remaking of about 200,000 zirconium-clad half meter long fuel rods containing about 100 metric tonnes of HM (97.2 % Th, rest U) per GWe year. It would also require lots of heavy water & huge reactor vessels.

A thorium burning MSR isobreeder should be much more affordable.

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PostPosted: Nov 19, 2016 10:12 am 
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darryl siemer wrote:
Here's a review written back in 1976 re thorium-burning CANDU-type reactors https://inis.iaea.org/search/search.asp ... RN:7258022

The bottom line is that isobreeding (of 233U) in CANDUs could indeed probably be achieved. However the cost would be pretty high because it would require the making/dissolution/reprocessing/remaking of about 200,000 zirconium-clad half meter long fuel rods containing about 100 metric tonnes of HM (97.2 % Th, rest U) per GWe year. It would also require lots of heavy water & huge reactor vessels.

A thorium burning MSR isobreeder should be much more affordable.


Recent work has demonstrated that should enriched zirconium be available (using laser processes or a plasma centrifuge, which AECL did a lot of work with in the 80s) the equilibrium cycle density in a 'normal sized' CANDU should be up to 15GWd/t. And with the reactivity insertion of the larger ~1,200MWe core that figure will likely climb further. That size of reactor is actually similar to the 640-tube CANDU 9 type core which will actually fit in the Darlington reactor vault, supposedly. I propose printing four unit stations that are modified Darlington generating stations with the larger reactor cores.

Reactor Vessels for CANDU are large but they aren't particularily expensive - they are after all just tubs in which the heavy water is placed and are basically at atmospheric pressure. And whilst heavy water is relatively expensive it is effectively eternal and the overall supply is limited only by the amount of equipment installed. There is absolutely no other constraint in supply.
And the advantage of a CANDU is that I could start construction (albeit without those 90Zr tubes) tommorrow and start the reactors up with the minimum of new technical development work, which means that research can go in parallel. If worst comes to worst the CANDUs can spend the first part of their life on a SEU uranium cycle whilst the thorium reprocessing technology catches up, or whilst uranium prices remain low.

An MSR might be cheaper in the very long term but given our present time limited scenario I propose we just build whatever we can right now - at least as a stop gap.


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PostPosted: Nov 19, 2016 5:55 pm 
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Dear E. Ireland...

I read about a dozen studies about the greenhouse effect from IPCC (climate hoax promoters) and critics. They show huge basic differences. A major difference in these studies is the effect of the clouds. A quantification of the green house effect and the main greenhouse gas H2O or the minor gasses CO2, CH4 is not done yet.

Personally I could imagine that Monte Carlo simulations of the atmosphere (summer, winter, EL Nino, tropical, desert, different parts of the ocean) could give some some answers and perhaps very rough quantifications of the greenhouse effect.

This would mean a lot of work for plenty of scientists and computers.


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PostPosted: Nov 19, 2016 6:43 pm 
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Climate models are only a supplement to climate history. It's not like modelling a reactor's neutronics, it's more building one, running it for four billion years, and leaving your progress notes lying around in huge piles. Louis Agassiz started reading them.
Fifty kilometres from here they've just been drilling cores from what was a deep, still volcanic crater lake, that's giving year by year readings of ice sheet collapse, and CO2 levels, from 23 million years ago.
http://www.nzherald.co.nz/nz/news/artic ... d=11732949


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PostPosted: Nov 20, 2016 7:41 am 
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Hi Jon,

it seems logic that CO2 level rise if the temperature (in the oceans) rise as the soluability of CO2 in sea water decreases roughly 5%/°C. Another effect is the permafrost in sibiria and Canada. These drilling does not provide any information on solar activity and other important things that influence the temperatures on our planet.
An interesting question is why the CO2 levels did increase from 300 to 400ppm since the 1st half of the 19th century. What is the influence of the warming since the end of the small ice age? Influence of corals and shells that bind CaCO3 from H2CO3 in the seawater? Permafrost? Degassing from the oceans?

The climate modelling as currently done gives you any result you wish.

A Monte Carlo simulation of the atmosphere similar to neutronic calculations of reactors could provide a direct quantitative data on how the climate gasses as H2O (main gas) and perhaps even how minor gasses as CO2 might influence temperatures.

Such a simulation could be manipulated as well by "optimizing" parameters. That means it is necessary to have critical peers to check it. Perhaps it is better to start such a study when the climate hoax is finished and the science becomes less political again.


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PostPosted: Nov 20, 2016 11:30 pm 
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The facts are already proving the models. Record hot years almost every year. Every 4 years there's one year where where temps fall back a little due to known oceanic patterns like la nina/el nino.
In 2 years the "climate change is a hoax" people will start questioning temperature measurements themselves trying to argue the data is fake too.
Its really sad this will happen while president elect tells his people that climate change is a hoax created by China. Really sad.

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PostPosted: Nov 21, 2016 3:53 am 
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Holger -
As I've told you before, and as you should know from your interest in matters nuclear, most of these questions can be plainly determined by isotopic studies. For example - 'A 1000-year high precision record of delta 13 C in atmospheric CO2 ', Francey et al, 1998.
file:///C:/Documents%20and%20Settings/User/My%20Documents/Downloads/16269-47244-1-SM.pdf


'While the main purpose of this paper is to present and document the 1000 year d13C record,
preliminary comment is made on major features. The 1000-year d13C record in Fig. 9 exhibits sys-
tematic variability on several time-scales. The overall decrease during the last 1–2 centuries is attributed to anthropogenic emissions. Maximum d13C occur during a 1600–1800 AD period, reported by Etheridge et al. (1996) as a ~6 ppm decrease and linked to ‘‘the little ice age’’ (LIA). '

You can assume that all these studies are gravy train hoaxing if you choose.


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PostPosted: Nov 21, 2016 6:33 am 
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jon -
'It makes me wonder if its not worth taking another look at a pressure tube, carbon dioxide cooled, heavy water reactor'
After the Swiss one and the Czech one both melted down, you might struggle to get funding. More than the average nuke startup, I mean.


E.Ireland -
The French one worked fine though! So its all square on that front I think.

E. Ireland, I've been scouring the net for this French CO2 breathing, heavy water drinking nuclear beast, and it's as elusive as the Loch Ness Monster ! Got a reference ?


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PostPosted: Nov 21, 2016 10:20 am 
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jon wrote:
jon -
E. Ireland, I've been scouring the net for this French CO2 breathing, heavy water drinking nuclear beast, and it's as elusive as the Loch Ness Monster ! Got a reference ?


The prototype was the EL4 reactor at Brennilis, which seems to have been relatively trouble free (After teething problems) until it was shut down by the fact it had become uneconomic next to the massive PWR fleet they were building at that time. 70MWe is rather small after all.
There is not much information about it, beyond that it had insulated zircalloy pressure tubes to handle the higher temperatures and such. Apparently they had a stagnant carbon dioxide layer maintained between an inner stainless steel guide tube and the outer zirconium-alloy pressure tube, connected at the low pressure end of the channel. But it appears that a Zirconium-Copper guide tube might be feasible thanks to alloys developed later in the project.

I believe a modified design using technology from the CANDU-SCWR might be able to reach teh pressures necessary for a direct supercritical cycle without having enormous neutron cross sections.


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PostPosted: Nov 23, 2016 8:17 pm 
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Thanks for that. Quite interesting as my sister married a Frog, and they have a house only about 50 km from the site. I knew the locals had got really toey about the proposed later PWR further west at Crozon, but didn't know the ' Breton Liberation Army ' had bombed Brennilis. ' Course if you wanted to be ' truthy ', you could say that all three prototype D2O/CO2 reactors blew up :lol:


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PostPosted: Nov 23, 2016 10:30 pm 
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Given the small size of carbon dioxide turbomachinery it might be possible to fit all the equipment inside the primary containment, although you might want a multi unit plant with an Ontario Hydro-esque shared containment, that way you could have a LOCA douse system in a vacuum building where the douse is sodium hydroxide solution or similar.
That way you can soak up the carbon dioxide in the coolant.

Raining sodium hydroxide solution in a fine mist on your turbine plant is probably a good way to ruin it after all.


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PostPosted: Nov 24, 2016 9:38 pm 
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Related news, Lylods has more or less approved Hyundai supercritical CO2 waste heat recovery generators for maritime applications, which have various size and containment requirement similarities.

https://www.maritimepropulsion.com/news/grants-aip-for-co2-517733


Sorta related is maritime use supercritical organic rankine cycle (SORC) systems (mostly as a bottoming cycle)

http://www.bmtdsl.co.uk/media/6374670/BMTDSL%20Supercritical%20Organinic%20Rankine%20Cycle%20(INEC%202016).pdf

The takeaway being that even though SORC is less cycle efficient than HRSG steam turbine systems, the size and layout flexibility is a net win for maritime applications (particularly if pared with a compact maritime gas turbine installation).

Granite Power was the SORC development partner

http://granitepwr.com/us/technology/


A side note elsewhere mentioned that for some maritime military applications for all electric drive/IEP, the convenience of putting generator equipment in a separate room from the shaft power source and using only a shaft coupling across a watertight bulkhead allows easier fire/damage containment measures by allowing different systems better suited for a particular class of fire (chemical or electrical). Interesting to consider relative to efforts to put the SCO2 turbine directly in the RPV of a nuclear system.


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PostPosted: Dec 29, 2016 5:18 am 
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I just read this paper (page 14), which gives a very detailed description of the technology:
http://www.gasturbineworld.com/assets/nov_dec_2014.pdf

Quote:
Efficiency gains for the air separa-
tion plant and compressors, the two
largest parasitic loads for the system
which have been included in all ef-
ficiency calculations, will further in-
crease overall system efficiency.


This was new to me as I thought that the ASU would degrade efficiency significantly.
Being no expert, I suspect that the adaption of the turbine to a LFTR will require a lot of modifications, as the cycle starts with an inlet temperature of 1150°C.


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PostPosted: Jan 07, 2017 5:01 am 
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Location: Taunusstein, Germany
Another interesting fact:
Quote:
The turbine exhaust gas enters the main recuperator heat exchanger, supplied by Heatric.


http://events.pennwell.com/pgi2016_v14/ ... 5954_1.pdf
Page 4


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