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Post by edireland on Oct 22, 2013 10:59:23 GMT 9.5
Free money to nuclear companies: "The 10% rate of return on investment reportedly given to EDF is double what is offered to renewables. When DECC was challenged over the reduction in the rate of return under the Feed in Tariff (FiT) for small scale solar PV, it stated, “we continue to consider that a significantly lower tariff is needed to provide generators with a rate of return of 4.5% to 5% for well-located installations. We are not persuaded that a higher rate of return would be reasonable given the focus of the FiT’s scheme ... and given the current investment climate."" www.theguardian.com/environment/2013/oct/21/new-nuclear-reactors-deal-consumersdefinitely a good deal for the people.... Rate of Return is irrelevent. The only thing that matters is that the electricity delivered is as cheap as possible. Unless you think the poor should subsidise the panels owned by the rich and upper middle classes (since they are the only ones who can afford the capital outlay?). That said, I still think it would have been better if the British State had simply built and operated the plant itself, but then I am an unreconstructed socdem.
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Post by edireland on Oct 22, 2013 2:47:37 GMT 9.5
And there is any particular hurry to advance the decomissioning process? The cheap solution is to wait. Just as instead of spending billions decontaminating farmland they should have just compulsarily purchased it all and thrown up perimeter fencing (as it would be far cheaper). It could then be periodically checked (every decade or so) and slowly released back into general use. Would probably form one hell of a nature reserve. yes, wait and spill nuclear waste into the environment. www.reuters.com/article/2013/10/21/us-japan-fukushima-strontium-idUSBRE99K01B20131021if you want to purchase the land, you have to pay real money for it NOW. And if the wind had blown the other way, we would just declare Tokio to be a wildlife paradise? cool! Obviously not since the land in Tokyo is actually worth something, so it would be worth decontamination. Farmland isn't worth as much as it would cost to decontaminate it so they should not bother to decontaminate it and just compulsarily purcahse it all and leave it for a few decades. And you should probably read that article before you post it.... the water was "as highly concentrated at 710Bq per Litre of Sr-90". That is to say.... pretty much uncontaminated.
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Post by edireland on Oct 21, 2013 0:45:21 GMT 9.5
And there is any particular hurry to advance the decomissioning process?
The cheap solution is to wait.
Just as instead of spending billions decontaminating farmland they should have just compulsarily purchased it all and thrown up perimeter fencing (as it would be far cheaper). It could then be periodically checked (every decade or so) and slowly released back into general use.
Would probably form one hell of a nature reserve.
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Post by edireland on Oct 18, 2013 12:38:57 GMT 9.5
Peat that is on fire does not tend to produce methane. It will produce carbon dioxide with a far lower short and indeed long term global warming potential.
And if you want to know how you coudl set such large peat fields on fire rapidly enough for not much money? ....
The 'flyaway' cost of a 300kT range thermonuclear device is only ~$1.3-2m.
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Post by edireland on Oct 16, 2013 21:02:49 GMT 9.5
It could never reach the Lower Explosive Limit unless all the peat magically decides to decay all at once.
Methane's lifetime in the atmosphere is too short, and if it was building up like that we could just set the remaining peat beds on fire before they can release methane.
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Post by edireland on Oct 9, 2013 3:12:33 GMT 9.5
You can "mass produce" most of the components of large scale nuclear plants, you just can't assemble them on a factory floor quite as easily.
Imagine, if you will, travelling work crews that assemble numerous reacotrs to identical plans on numerous sites in sequence.
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Post by edireland on Oct 2, 2013 11:03:53 GMT 9.5
Cool kit, huon. Thanks for the link. I still see proposals for street-sited rail trolleys in urban areas (Denver, Salt Lake City). I have to assume their proponents are just not familiar with trolley-buses. Cheaper, faster, and much more flexible. Rail is fine, provided one has dedicated right-of-way. Rail trolleys and motor cars have never well mixed. Indeed, you tend to end up with things like this (from the last few boat trains to serve the Weymouth Harbour port in the 80s):
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Post by edireland on Oct 2, 2013 1:23:31 GMT 9.5
Medium power reactors have little or no benefit over Larger ones, require additional units with additional political costs and scattering of infrastructure all over the place which is not necessarily the best economic option. (Power lines are cheap, having multiple reactor sites probably isn't).
As to LWRs being developed for submarines, that primarily refers to PWRs, BWRs came about as part of the Army Atomic power programme that wanted mobile reactors to provide power for bases. You can't tar all LWRs with the brush of the PWR.
And as to that list of Islands in Indonesia that you think would be better off with SMRs than a giant nuclear power plant I note the following: Bangka 960,692 - only 13km from Sumatra so could easily draw power from it, without even bothering with HVDC Nias 756,338 - 110km from Sumatra, so a VSC based HVDC solution would be easily capable of providing all its power from the Sumatran grid Sumba 686,113 - a 45km undersea jump gets you to the island of Flores which has a population of 1.8 million and is part of the same island chain as Bali and Java Halmahera 449,938 - a 200km undersea VSC HVDC line gets you to Papua which has a population of several million Buton 447,408 - 6.5km from Sulawesi, so trivial to connect it even without a HVDC connector Ambon 441,000 - 12km from Seram, so see below Seram 434,113 - 137km gets a HVDC Line to Papua, allowing both Seram and Ambon to tie into the Papuan grid Bintan 329,659 - 130km from Sumatra over a long chain of islands seperated by relatively shallow channels, an AC connection with reactors would be feasible, let alone HVDC. Muna 268,140 - 500m from Buton, so really easy to connect to Sulawesi. Belitung 262,357 - 100km from Bangka over a chain of three islands, so VSC HVDC should have no trouble at all Tarakan 193,370 - 3.6km from Kalimantan, so AC connection will certainly suffice here Ternate 185,705 - 12km from Sulawesi, so easy to connect. Buru 162,116 - 70km from Seram via three intervening islands Alor 145,299 - part of the same Island chain as Flores and thus couplable to the larger Balian-Javan grid Rote 119,908 - trivial to connect to Timor but coudl also be connected to Sumba and hence Flores Lembata 117,829 - part of the same Island chain as Flores and thus couplable to the larger Balian-Javan grid Biak 112,873 - 130km from Papua Peleng 109,319 - 14km from Sulawesi Bengkalis 108,700 - 6.8km from Sumatra
As you can see, every one of these islands is in a position that would allow it to be connected to a larger grid using the currently available Voltage-Source-Converter HVDC technology. Recent advances that allow for multi-terminal HVDC links capable of black starting the connected grids and the advances in IGBTs that allow converter stations with powers down to the tens of megawatts have rather eroded the market for SMRs in my opinion. Additionally many of those larger islands are sufficientyl close that the possibilty of a Pan-Indonesian interconnection cannot be ruled out.
With undersea HVDC cables now in service for distances of several hundred kilometres at depths of up to 1650m, the SMR market is rapidly diminishing if capital-lumpiness benefits (which I believe are merely a result of today's flawed electricity market model) are ignored. Proposals to extend HVDC lines to 2000+m depth and the fact that these lines can remain competitive above-water for thousands of kilometres do not bode well.
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Post by edireland on Sept 30, 2013 1:22:59 GMT 9.5
A floating platform for a commercially viable nuclear power plant for large grids would be prohibitively large.
A single ESBWR containment weighs something on order of a quarter of a million tonnes
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Post by edireland on Sept 29, 2013 22:43:36 GMT 9.5
A seawater cooled reactor could probably keep functioning despite the ash load if its water intakes are designed properly.
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Post by edireland on Sept 22, 2013 7:58:52 GMT 9.5
Frankly we should just forget EDF and build the reactors using public money.
But unfortunately the political climate prevents this.
Instead, with a strike price of something like ~£110/MWh we end up paying a ridiculous amount to EDF for no good reason. It is the mother of all Private Finance Agreements.
8760hr/year, assume a 90% capacity factor and a 3GWe plant would produce something like 23,652,000MWh of electricity per year. With a "value" of ~£2.6bn.
Or $4bn+.
That is frankly absurd, considering that the contract lasts 15 years at least and is adjusted for inflation, meaning they will get something like sixty billion US dollars and have a plant with 75% of its operational life remaining at the end of it.
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Post by edireland on Sept 22, 2013 7:56:58 GMT 9.5
I should write a short story where humanity uses the glories of atomic fission to free Prometheus from his prison and then blows apart Mount Olympus with massed nuclear weapons.....
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Post by edireland on Sept 21, 2013 20:35:14 GMT 9.5
They won't have to.
They will be required to by the Japanese government.
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Post by edireland on Sept 21, 2013 20:34:36 GMT 9.5
The Lib Dems will say anything to escape the fact they are going to lose 80% of their members of parliament at the next election.
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Post by edireland on Sept 18, 2013 19:16:46 GMT 9.5
It may be less risk during an accident, but cutting down the amount of energy in the pack represents a risk of the bus becoming stranded in heavy traffic.
Especially, if for example, it has been fitted with air con (which is going to be increasingly expected on all buses I think in the future) and is stuck in traffic.
The auxiliaries could easily run the supercapacitor pack down requiring far larger packs than actually required to traverse the distance in ideal conditions, (and route diversions will require significant energy storage capacity that will have to be provided either by batteries or an auxiliary generator).
And I live next to a bus route where, for most of the day, the time between bus arrivals is closer to 10 seconds than a 1000. (Over sixty buses per hour for most of the day)
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Post by edireland on Sept 18, 2013 8:56:58 GMT 9.5
Flash charging buses is problematic if done on a large scale IMO thanks to grid stability issues.
I am much more of a fan of trolleybuses.
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Post by edireland on Sept 16, 2013 18:28:07 GMT 9.5
Yes, but even at 700mph it is going to take a while to get several hundred miles (which is presumably the sort of journey length we are going for?). Passengers probably won't like not being able to move a muscle. (Since if they have they are holding say a 500mL bottle of coke in front of them when the acceleration commences it will become a ten kilogramme projectile dropping onto their chest, and that is before we include the arm holding them).
Laptops become 20kg weights smashing into your chest.
Its a nightmare.
And remember unless we want all the capsules to do exactly the same journey we need some pointwork to change routes. This pointwork has to confirm that the previous vehicle has cleared the junction, then it has to set the new route required by the next vehicle, and then it has to gain interlock to confirm the new route has been set. It has to have interlock prior to the next vehicle being unable to stop before the junction or you risk a vehicle slamming into a half set junction mechanism.
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Post by edireland on Sept 12, 2013 16:35:51 GMT 9.5
Even 20g is far too high for braking performance. That would require everyone to be restrained in a multi point harness and orientated to counteract sudden g-forces that could come from nowhere. It would mean any time would be absolutely lost since you would not be able to move a muscle. 1g at most.
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Post by edireland on Sept 11, 2013 20:35:32 GMT 9.5
There was no point evacuating until actual radiation release of dangerous levels was detected (as the evacuation itself will produce nonzero casualties).
Frankly it might have been better if they had gagging orders on the press to avoid a panic but that sounds awfully totalitarian.
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Post by edireland on Sept 6, 2013 0:06:23 GMT 9.5
India has its own energy-security reasons for pursuing it, the Russian Fast Reactor programme appears to be going nowhere fast and the Chinese are just throwing money at everything that moves.
I don't think LMFBRs are going to be a major player. Especially if seawater uranium extraction works.
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Post by edireland on Sept 4, 2013 22:57:51 GMT 9.5
Also I am pretty sure you can't use ordinary LD50 doses when your dose is being concentrated itno the bottom 50cm of your body.
Unless you are suggesting that the workers will strip off and then start wallowing in a strange pool of water in the middle of the plant.
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Post by edireland on Sept 4, 2013 10:26:18 GMT 9.5
Why should the government or the people pay for the collosal subsidies provided to every alternative?
And these things sound expensive but aren't really expensive per kWh of electricity produced by nuclear in Japan over the last 60 years.
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Post by edireland on Sept 3, 2013 22:20:02 GMT 9.5
It has capsules seperated by 0.125 seconds moving at several hundred miles per per hour. At 700mph supposed 0.05 second seperations are practical which translates 15.6m apart moving at ~310m/s. As the vehicles are 4m long that takes us to 11.6m actual spacing.
That means that in order to not get catastrophic chain reaction pile ups a capsule would have to be able to slam on the brakes at something approaching 440g to avoid a collision.
So you can see this is rather ridiculous. With the same safety principles I could run railway trains with 30 second headways, and since this claims the full theoretical capacity is available for us and not 75% of it like the HSR example.... that takes me to 156,000 people per hour at the very least.
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Post by edireland on Sept 3, 2013 7:44:39 GMT 9.5
Essentially a decent pair of waterproof boots will provide almost complete protection from the spill.
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Post by edireland on Sept 2, 2013 22:56:48 GMT 9.5
This is something I found about it a while back, Hitachi are developing it along with their fast spectrum BWR. The primary reason that multiple recycle is problematic in LWRs is because the increasing plutonium fraction drives the void reactivity coefficient positive which causes obvious design issues. RMWR and other development projects seek to use clever designs to overcome this problem. So an excess of Pu239 makes a loss of coolant significant as a loss of absorber... Then surely the coolant could be designed less absorbtive, say, as HDO rather than H2O. Yet the web entry on RMWR says less water. The RMWR is really a family of designs, although the Hitachi one seems far more technically promising. I have seen scattered references to using heavy water in a fairly conventional PWR primary loop however, but this appears to be a less heavily investigated path to the RMWR objective. It is not so much the 239Pu either, it appears to be many of the isotopes of Pu have this effect and since the proportion of plutonium in the fuel has to keep increasing with each recycle to make up for its reduced "grade" this becomes an issue. I realise that fewer U fissions means fewer delayed neutrons and thus faster rise time. But it only needs to be longer than the designed feedback response. Perhaps that minimum U could come from a continuous conversion of Th232. Perhaps fast neutron spectra are possible in water cooled designs. That suggest the possibility of an initial plutonium charge, then burning all the higher actinides. Your reference to Hitachi's fast BWR is intriguing. Do you have a link? (The link above fails) Hhhm, odd, that links work fine for me. Anyway, the Hitachi programme is known under a variety of names, RMWR (as a genericised thing) the RBWR (Resource Renewable BWR) and numerous other bits, but I think I have a core design link for a 330MWe design that shows the concept rather nicely. Here we go
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Post by edireland on Aug 30, 2013 21:11:51 GMT 9.5
200kBq/L? They lost ~300kL. That means they lost something in the region of 60GBq. The specific activity of 137Cs is something like 814GBq/g.
Which means they lost something like 70 milligrammes of Caesium-137 equivalent.
So they haven't really very much at all, this is the problem with the Becquerel, it is such a tiny unit that you always end up with huge numbers.
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Post by edireland on Aug 30, 2013 21:06:37 GMT 9.5
A toxic legacy that there will be a handful of hectares of land where you cannot go digging? Or a few more hectares where it would be inadvisable to grow food?
If that is the extent of the toxic legacy left by our energy generation infrastructure I would think that it would be a glorious success for humanity.
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Post by edireland on Aug 29, 2013 21:28:56 GMT 9.5
A puddle next to a waste tank is "suspicious", a puddle in the middle of a concrete apron miles from anything is not.
Is it garbage simply because it doesn't decry the loss of some contaminated water as the end of humanity with thousands of deaths to be caused by it?
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Post by edireland on Aug 29, 2013 3:11:53 GMT 9.5
edireland-- You're overly pessimistic about tube travel. The payoff is speed faster than a jet with energy consumption below that of an electric high-speed train. It may not be ET3 that does it, but surely someone, sometime will be able to pair evacuated tubes with high-temp maglev. The problem with all these technologies is making them not horrendously fail-deadly and at the same time delivering anything close to the capacity that more traditional systems can reach. Conventional HSR can put 1300 seat trains down a line 18 times per hour (if you go for Japanese seating densities you can get that figure up to 1800 seats). Delivering 23400 (or higher) seats per hour with an alignment as wide as a two track High Speed rail one is a massive challenge. Hyperloop simply couldn't manage it. The seat costs of HSR will simply be so much lower than these more exotic alternatives that noone takes them up on them despite the speed advantage. As for cost, the ET3 website has this to say (FAQ, "Would creating tubes large enough to allow passengers to walk around be an option?"): "The cost of ET3 us very sensitive to the tube diameter. If the capsules were made 'as big as a bus' it would increase the cost by a factor of about 30.... "The most important thing to get correct with ET3 is the capsule diameter. If the diameter is a little too small ET3 will not achieve sufficient utility to carry most cargo and passenger comfort would suffer. If a little too big, the cost prevents maximum use. Our considerable research into this topic of optimal size indicates that the optimal capsule diameter is 1.3m (51") and the corresponding tube diameter is 1.5m (60")." www.et3.com/faqThe capsules must also be very light. I'll bet BMW, using the i3's new carbon fiber technology, could produce a great capsule. That is going to be rather uncomfortable for the passengers, and it causes problems for escaping in a pressurisation loss accident. You have to be able to either get people out of the vehicles very rapidly or very rapidly repressurise the entire tunnel, or both. We are talking seconds to sea level pressure or we end up with serious problems in an accident, assuming you can have an accident that doesn't involve catastrophic death of everyone really quickly. And then you have to engineer all the tubes to contain teh debris from one of these catastrophic accidents. Hear that? That is the sound of the price shattering the ceiling.
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Post by edireland on Aug 27, 2013 21:53:40 GMT 9.5
Plutonium can only be recycled in a light water reactor while there is Pu239 to burn. The accumulation of Pu240 eventually becomes a neutron poison. Yes, at which time the plutonium should be stored pending the deployment of a significant fleet of epithermal or fast reactors capable of destroying it. This is why the French are storing their spent MOX fuel rather than reprocessing it en-masse. In fact an RMWR may be able to eat 35% fissile Plutonium (spent MOX grade) and 237Np with ease and without requiring absurd dilution levels. Could we have a link to the FLUOREX process please? I couldn't find anything on the web. Its hard to find exact information on, although it is mentioned in various IAEA TECDOCs. This is something I found about it a while back, HItachi are developing it along with their fast spectrum BWR. I have seen studies that suggest that a future fast reactor could operate using entirely Pu-240 makeup assuming it was given a sufficient fissile startup feed. Remember that Pu-240 is a "neutron poison" in the same way that U-234 is, absorbing a neutron makes it fissile again, unlike some other poisons. The primary reason that multiple recycle is problematic in LWRs is because the increasing plutonium fraction drives the void reactivity coefficient positive which causes obvious design issues. RMWR and other development projects seek to use clever designs to overcome this problem. The "problematic" nature of aqueous wastes is often overstates by the anti nukes, remember that the PUREX plant at La Hague operates so well that even French Greenpeace have given up attacking it. FLUOREX requires only 10% of the material to go through the PUREX process and will thus reduce the aqueous waste content and provide a ready stream of uranium for re-enrichment without a separate conversion step.
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