1. I wasn't the one that calculated that
2. If the speaker disagrees with the assumptions, challenge the assumptions rather than resorting to an argument from authority.
Must can be wrong and has been wrong. Most likely though we're not getting the full scoop in the story here. There's probably a load of caveats and detail to their plan that cannot simply be boiled down to a simple marketing snippet. Unfortunately, that's how marketing works.
Say what? You mean NIF? That's a completely different facility utilizing completely different physics to achieve a completely different outcome.
Anyway, let's get back on track. I await your numerical analysis of the feasibility of destruction of nuclear waste by particle accelerators (your original claim, no goalpost shifting to lasers or any other tech). Here's again what you said:
Your proposal still risks meltdown while the accelerator controlled system may avoid that. But it does not get all the fission products. For those, further fission through proton collision will do the trick. And yes, that costs energy. Notice we are not looking at neutron cross sections here. Heck, we could accelerate the fission products themselves and have them as both bullet and target.
I eagerly await your analysis and I hope, again, it's going to be quantitative, not just a bunch of handwavy statements linking back to source material that doesn't actually support your case. As for laser transmutation, the best I can find is some really early research on possible 129I transmutation, but the results being achieved there are so far removed from being practical, that I think fusion power is going to come around before that (e.g. transmuting a few hundred atoms per laser shot, one shot being only possible once every few minutes with lasers of state of the power density - this is a very long way away from being practical).
Besides which, even if they spent $1bn on energy it would be worth it for a factory consuming that much. With grid feed-in during the summer and only maintenance costs at other times it would pay for itself pretty quickly.
Go ahead, run the numbers on that. By my estimation, $1bn at ~$0.07/kWh (industrial rate) and an average 2400MWh consumption a day would buy them over 15 years' worth. Meanwhile, the cost of covering 1/2 of their roof (gotta leave some gaps) at a 10% capacity factor with panels at $1/W would cost ~$130M and would provide all of ~13% of their yearly demand. If you extrapolate to 100% of their yearly demand, the cost of such a solar installation comes to around $1bn. And that's before you get to storage. Even adding something modest like 1 day's worth of storage in batteries at $100/kWh inflates the cost to $1.25bn without even talking about power electronics, environmental conditioning systems and actually building a functioning system out of it (rather than just a warehouse full of cells). Add even modest amounts of storage, like 3-4 days and the whole cost structure spirals wildly out of control.
Like you said, they'll stay firmly connected to the grid, use its generation capacity for bridging the times when their own solar & wind will be useless and then sell the surplus back at a nice fat feed-in rate, IOW everybody else on the grid will subsidize them. Meanwhile, greenwashers like yourself will keep posting BS articles about how "green" the factory is, smugly feel you've done enough for the environment, while CO2 emissions will not really decline very much and the atmosphere will again take one for the team.
called a IRBM.... So you just re-invented the ballistic missile.
Yeah I know it exists:) I was just demonstrating that the technology already exists. The prospect of a true hypersonic missile would be to stay inside the atmosphere, relatively close to the ground, yet provide the capability to strike a target a short-to-intermediate range (<1000km, probably way less) with little to no over-the-horizon warning time. Something like the P-800 Oniks (which can reportedly do M4+ over a distance of ~100km), just much faster.
Yeah, I'm aware of the problems with corrosion of high-temp lead, though this can somewhat be kept in check by limiting the temperature (it hurts efficiency, but might be worthwhile - really depends on the design). It really comes down to materials science and like you say, research on lead cooling has been thin so far. I'd love to see a lot more open-access research in this area.
As for sodium cooling, it has its own problems, but AFAIK it doesn't react explosively in air. It can burn, but if I understand it correctly, the reaction isn't exothermic, so it'll quench itself quite rapidly. Now water is a different story. A sodium-cooled reactor in a potential flood area (ahem, Fukushima Nr.1) is about as dumb an idea as I can think of. Fortunately, the improved thermal efficiency gives you some more leeway to run pumps and pump the water up a hill (like reactors #5 and #6 at the Fukushima Nr.1 plant, which were largely unharmed by the tsunami which totally devastated their lower-sited siblings).
I'm not a fan of light water reactors either, but you need to understand that the public isn't aware of the details and intricacies of reactor design. To them terms which make an engineer cry happy like a little girl, don't mean anything. I mean FFS most of them still think nuclear reactors can explode like atom bombs. They saw Chernobyl and Fukushima, they saw "boom", it's a nuclear reactor, therefore "nuclear boom".
I also think and hope education can change that, but that's a long road ahead and TRU-burning BWRs could work in the interim to help jumpstart that (since we already have them).
the lowest possible temp is -273.15C or -459F, or 0 kelvin. (absolute zero). Increase in flame temp when combusted with air will be approx +10.4C.. (0.04 * 2483K) + (0.96 * 2223K) - 2223K = +10.4K.
You've got a mistake there, 2223K is the flame temp for CH4. Natural gas is 2233K or 10K higher (because it's not pure CH4). The difference, however, is largely inconsequential, it's a 1% increase in absolute flame temperature (exactly like I said), at best (actually 0.44%, but we'll let that go).
+10.4K/(2223K-290K(ore 323C)) = 0.53%(17C) to 0.55%(50C) increase in efficiency to help offset 4% H2's 2.71% reduction in energy content. Since most applications are direct thermal usage(water/hot air/etc) no additional losses will be incurred.
Now hang on, you can't just take the flame temperature and call that your working fluid temperature, that's not how it works in heat engines. Gas-based heat engines (CCGT - the most efficient ones, not talking about ICBs, those have very poor efficiency) use the hot flame to heat a working fluid (typically superheated steam), which is much cooler than the flame itself. I used an 18C coolant temperature (cold water) and 60% efficiency to back-calculate the minimum ideal working fluid temperature (~454C hot vs. 18C cold will give you ~60%). So a 1% increase in absolute flame temperature can at best give you a 1% increase in absolute working fluid temperature, which means your working fluid goes from 454C (727K) to 461C (734K). However, the gains here will be much more modest because you can't just step over a heat exchanger's maximum temperature willy-nilly, or bad things will happen to it, which is why I rounded to 460C (I'm a generous guy, I know:)). So 460C hot vs. 18C cold gives you 60.3%, or about a 0.3% gain.
Now as for "direct thermal usage (water/hot air/etc)", these applications are not heat engines, they don't convert heat energy into work (J -> J/s is a heat engine, J -> J is not), so for them an increase in flame temperature means nothing. For example, it takes the same amount of heat to raise 1kg of water by 1C, regardless if the absolute temperature of the heating source is 100C or 500C, it's still 4.18kJ/kg.C.
Had to google the abstracts of the report and its conclusions are highly interesting. They claim to be able to breed at a ratio slightly above 1.0 in a BWR and even slowly consume TRUs by 10% per reprocessing step with unlimited reprocessing capability. Results of the report:
The analyses collectively indicate that the two reactors appear to be able to achieve their design objectives: The RBWR-AC provides an equilibrium-cycle breeding ratio of slightly above 1.0, thus providing for a self-sustaining fuel cycle in which depleted uranium is used for the makeup fuel. The RBWR-TB2 is capable of unlimited continuous recycling of TRU while consuming on the order of 10% of the loaded TRU per recycle (after accounting for the newly generated TRU). Most results confirmed the values estimated by Hitachi. Some differences among the predicted reactivity coefficients need to be evaluated further.
This has the potential to be a game-changer if true, as we could simply use existing reactor designs such as the ABWR (of which there are several operating already) to both burn waste and breed fuel indefinitely from U238 feedstock.
It's possible they plan to only burn stuff beyond Pu in there, as that can already be consumed in MOX (which however produces more of the higher TRUs for the reasons you noted). It's really hard to tell what they're trying to do here without more detailed data on the actual fuel composition.
Also weird, is Hitachi already has a TRU burning design, the S-PRISM
It's possible they're having trouble getting a dedicated TRU burner design approved and built (there might be little economic incentive and much public opposition to new nuclear plants, no matter the safety of the technology), hence why they might be motivated to try and design fuel that can consume TRUs in standard BWRs, of which Japan already has quite a few.
I agree that burning the crap off is a good thing, but why tack on an expensive piece of extra equipment when pretty much the same effect can be achieved by being smarter about core design? I'm just not seeing the big advantage here.
I never quite understood the allure of ADS. To my eyes it just looks like an exceedingly difficult way of achieving criticality. Given a good design, a reactor will self-regulate by its own negative temperature coefficient, so an external driver isn't strictly necessary and shutdown can be performed by passive systems that are equally dependable as cutting power to the accelerator, e.g. by suspended or spring-loaded SCRAM rods. There is the interesting proposition of not having to reprocess the fuel when running a thorium breeder cycle in order to extract the bred fissile and load it into the core, since one can boost the neutron budget externally, but that needs to be weighed against the pretty steep cost of a high-powered accelerator (in terms of current, not just particle energies) and accelerator reliability issues.
They don't, but the ratio of absorption to fission in the thermal spectrum for them is pretty bad, so that can mess up your neutron budget. Depends on the exact composition, though - each reactor produces a slightly different mix and that makes the TRU content in spent fuel fairly heterogeneous, which complicates reactor design and makes fabrication of reliable fuel fairly expensive (hence why MOX fuel only contains the Pu content, not all the other TRUs and even so it's much more expensive than fresh Uranium fuel).
I don't think they do so in the breeder cycle - their neutron loss margins are fairly thin, hence why most designs propose extracting at the Pu-238 step (unusable for weapons, but great for space batteries). The burner cycle might be better in this regard. Fast reactors are able to do it, they have plenty of neutrons to spare.
What is "neutron saturation transmutation"?
I'm also skeptical of their claims, as it appears to be a thermal-spectrum light water reactor and it's quite difficult to consume TRUs completely in the thermal spectrum, the neutron absorption cross sections are fairly large. Maybe they've got higher enrichment and so shitloads of excess reactivity, so they can afford to lose the neutrons, in which case I seriously hope they have a strong negative temp coefficient. Don't know, would be good to learn the details.
Not sure about the likelihood of meltdown being increased, though. I don't think the decay heat profile of MOX is significantly different from regular enriched Uranium fuel (decay heat melted Fukushima fuel, not fission heat).
I'm not convinced of the first-strike capability of hypersonic vehicles. Even at fairly highly hypersonic speeds (M10), the vehicle still takes considerable amounts of time to travel a substantial distance (1000km takes about 5 minutes at M10) - by that time satellite-based detection systems can react and a ground-based counter strike can be initiated (modern ground-based ICBMs can launch in less than 30s, and SLBMs are also an option). At certain distances a good exo-atmospheric missile on a depressed trajectory can strike faster than that. Assuming a 90s boost phase with the final ~10s being used to depress the trajectory arc downwards + a few minutes to travel the 1000-2000km towards the target at easily 4-5km/s. Military solid-fueled missiles have very high thrust-to-weight ratios to shorten the boost phase as much as possible. I think the more problematic aspect is that defending against low-altitude (well, relatively, I mean we're still talking 10-20km in altitude, otherwise the air resistance and shock heating just kills it) hypersonic vehicles in a local theater war scenario can be very difficult - at 10km altitude with the over-the-horizon flight time you only get maybe 30-60s of warning (by my rough calculation at 10km horizon is ~250km away) - depends on radar position and capability, of course.
Your analysis on usability by crazy/unstable countries, I think you're spot on. The big boys have bigger and perhaps more capable toys. It's those crazy wackos who might be tempted (Iran to Israel is only about 1000km, as is NK to Tokyo, so 5 minute strike capability would sound like a sweet deal there).
You seem to have reduced renewables to just wind and assumed that I think the country should be powered 100% by wind, That is incorrect.
I'm not, but I'm looking at the cheapest renewable. There is some hard (dispatchable), but highly limited renewables, like hydro and biomass. These can make some contribution, but it's rather small. If you look at the fastest growing ones, it's wind & solar.
Tepco lie habitually. Their own statements show they don't know what's going on.
Them not knowing doesn't mean you can just make stuff up and fill in the gaps with whatever you like. The linked article is still over a year old and could indicate a temporary condition. Moreover, it's notably light on radioactivity figures for the contaminated water. When you have a look at an article on the guardian which mentions at least some quantitative measurements, it says "quantities of radioactive caesium-134 and -137 in locally caught fish have fallen to levels close to the government-set safe limit of 100 becquerels per kilogram", while noting that it's "scant consolation". I don't know about other people, but knowing that the level of contamination is falling is indication that the situation is definitely improving. And 100Bq of Cs137 (by far the more active of the two) corresponds to concentrations of 0.22 picograms per kg of water (or less than 1 part in one quadrillion), that's pretty close to the detection threshold of the measurement hardware (which is very low) and means you really don't need to be worried at all. There's shitloads of other much more toxic stuff in much larger concentrations in that water that has nothing to do with radiation - honestly, think about the danger rationally.
Hinkley point will get tens of billions in subsidies at the guaranteed rate of £92.5/MWh - roughly double what will be paid for gas, coal, wind etc.
And I don't agree with that. Did you read what I wrote? I said Hinkley Point C was a bad deal.
If renewables are so unobtainable why are Scotland aiming for 100% renewable by 2020 after having beat their goal of 31% renewable by 2011 set in only 2007.
Because you don't understand how the accounting there works. They look at generation, divide by consumption and declare victory. But last I looked, Scotland isn't an island somewhere in the Pacific. In fact a significant amount of that will be pushed south and reimported from fossil fuel generation later when the wind isn't blowing. But since the overall generation divided by their rather limited population (and thus limited consumption) is high, they can declare "100% victory!" Unfortunately, in the big picture, they are hardly making a difference: http://www.gridwatch.templar.c... <- study these graphs, they're not made up. Portugal is probably the same story with Spain, but I'd have look it up (TBH, I'm not familiar with their grid, I know the UK's and Germany's and I've also studied German renewable growth vs CO2 trends - they won't make their 2050 commitment if they continue at the way they've been going since 2004. In fact, by my estimation after they have expanded to 100% renewables in 2055, they'll still be at 40% of 1990 CO2 levels. Can share the raw data, if you like.).
Iceland is 100% renewable electricity, and much of their heating is renewable.
Norway is 99% renewable electricity.
These two are extremely out of the ordinary examples. Both have very low population densities (Norway 1 order of magnitude less than the UK, Iceland 2 orders of magnitude) and both have specific geographies. Iceland is a highly active volcanic island, so it has ample geothermal resources (and I acknowledged that). Norway has lots of water flows, so it has plenty of hydroelectric resources (and I ackn
Or just stick in an simple power limiter which trips a breaker if you go over the limit:) Trouble is, our current energy system originated in the days of yore when we had to consume significant amounts of fuel (and thus cost) to produce a unit of energy. Our energy markets are geared towards it, our grid control is geared towards and people don't like changing systems with lots of investment behind them and which aren't necessarily broken.
If we were building a new zero-carbon grid green field-style, it might well be cheaper to just lose the stupid meters (and spending time reading them, processing them and collecting the varying amounts), put in a simple circuit breaker and be done with it.
I don't see any need to do that, I never suggested that. Just make up some crazy math why don't you.
Oh sure, there's no such thing as a month-long wind lull (by which of course I mean time of very low production). Oh wait, just ignore June.
Note that Tepco itself has admitted that 300 tons of highly radioactive water is leaking.
Your reading needs work again: "Hirose stressed that Tepco does not believe all 400 tons of the water entering the sea is contaminated."
Contrast with what you said: "Are you aware that Fukushima is leaking at least 400 tonnes of highly radioactive water every day." Your link doesn't say it's all contaminated, or that it's "highly radioactive" (which I asked you to substantiate with figures again, and of course you can't).
The point is 0.007km3 is absolutely miniscule compared with hundred of massively larger reservoirs around the world which rand from hundres to thousands of km3 which givens them huge pumped hydro potential.
Go ahead, make the investment pitch and start building. Or you might for a second consider that people smarter than you have thought about this and came to a different conclusion, which is why you're not seeing the projects springing up like mushrooms after rain. Why do you think is that?
That would cost a lot more than £450 billion
Bold prediction, considering that's what a utility building the pilot deployment (= expensive) in the US is paying (where median household income is even higher than in the UK). Moreover, when you buy identical products in bulk, you get volume discounts and volume production benefits - that's pretty normal, even in nuclear power. Even using the hugely overpriced £17B Hinkley Point C, you'd still get ~40GW worth of power onto the grid (supplanting all fossil fuel sources) out of a total of 26 reactors. I don't think Hinkley Point C is a good deal for the good people of the UK and I think the government seriously dropped the ball there, but don't try and extrapolate one government's failure on price negotiation on one project to a whole global industry. If the government were serious, set policy so that industry would be reassured that they won't get whacked over the head by undue regulatory burdens down the line and not limit the selection process for political reasons (it has to be European or nothing!), you'd see utilities even in the UK being able to get much better deals, as others already get in other countries.
Err. The 4% H2 portion burns hotter than other 96% ch4 & c2h6, so the hotter flame temperature is going to help make up for some of the 2.8% loss in energy density for any given volume of gas.
Adiabatic flame temperatures don't mean higher energy release. At best they mean higher heat engine efficiency and you can't just start to run a boiler significantly hotter than it was designed to, or you'll get a rather nasty looking result. Moreover, when you *do* look at the adiabatic flame temperatures of NG and H2 in air, you'll see that a 4% concentration of H2 gives you at best an extra 10C, or about 1% of extra absolute temperature. Using 60% as the efficiency of an idealized Carnot cycle, we see that, assuming 18C cold water cooling, the lowest possible working fluid hot temperature is ~454C. A 1% increase in that gives us ~460C, or an efficiency boost of a whopping 0.3% (ideal best case). In short, not really something to write home about.
Beyond 4%, I expect we'll build a separate underground H2 storage network
Sure, but that'll cost extra, where the entire premise of the original claimant was to utilize the existing gas grid infrastructure (for which we only need to pay for mostly O&M).
Slashdot Mirror
1. I wasn't the one that calculated that
2. If the speaker disagrees with the assumptions, challenge the assumptions rather than resorting to an argument from authority.
Must can be wrong and has been wrong. Most likely though we're not getting the full scoop in the story here. There's probably a load of caveats and detail to their plan that cannot simply be boiled down to a simple marketing snippet. Unfortunately, that's how marketing works.
So what are the numbers on that?
That gives us the mass that would need the more energetic proton (or perhaps tritium) treatment.
So what are the numbers on that?
Anyway, let's get back on track. I await your numerical analysis of the feasibility of destruction of nuclear waste by particle accelerators (your original claim, no goalpost shifting to lasers or any other tech). Here's again what you said:
Your proposal still risks meltdown while the accelerator controlled system may avoid that. But it does not get all the fission products. For those, further fission through proton collision will do the trick. And yes, that costs energy. Notice we are not looking at neutron cross sections here. Heck, we could accelerate the fission products themselves and have them as both bullet and target.
Support these claims with numbers.
I eagerly await your analysis and I hope, again, it's going to be quantitative, not just a bunch of handwavy statements linking back to source material that doesn't actually support your case. As for laser transmutation, the best I can find is some really early research on possible 129I transmutation, but the results being achieved there are so far removed from being practical, that I think fusion power is going to come around before that (e.g. transmuting a few hundred atoms per laser shot, one shot being only possible once every few minutes with lasers of state of the power density - this is a very long way away from being practical).
Besides which, even if they spent $1bn on energy it would be worth it for a factory consuming that much. With grid feed-in during the summer and only maintenance costs at other times it would pay for itself pretty quickly.
Go ahead, run the numbers on that. By my estimation, $1bn at ~$0.07/kWh (industrial rate) and an average 2400MWh consumption a day would buy them over 15 years' worth. Meanwhile, the cost of covering 1/2 of their roof (gotta leave some gaps) at a 10% capacity factor with panels at $1/W would cost ~$130M and would provide all of ~13% of their yearly demand. If you extrapolate to 100% of their yearly demand, the cost of such a solar installation comes to around $1bn. And that's before you get to storage. Even adding something modest like 1 day's worth of storage in batteries at $100/kWh inflates the cost to $1.25bn without even talking about power electronics, environmental conditioning systems and actually building a functioning system out of it (rather than just a warehouse full of cells). Add even modest amounts of storage, like 3-4 days and the whole cost structure spirals wildly out of control.
Like you said, they'll stay firmly connected to the grid, use its generation capacity for bridging the times when their own solar & wind will be useless and then sell the surplus back at a nice fat feed-in rate, IOW everybody else on the grid will subsidize them. Meanwhile, greenwashers like yourself will keep posting BS articles about how "green" the factory is, smugly feel you've done enough for the environment, while CO2 emissions will not really decline very much and the atmosphere will again take one for the team.
With all due respect to your calculations, I'm willing to believe an authority figure more than math.
FTFY. Simply because he's correct on some things, doesn't mean he's infallible.
called a IRBM. ... So you just re-invented the ballistic missile.
Yeah I know it exists :) I was just demonstrating that the technology already exists. The prospect of a true hypersonic missile would be to stay inside the atmosphere, relatively close to the ground, yet provide the capability to strike a target a short-to-intermediate range (<1000km, probably way less) with little to no over-the-horizon warning time. Something like the P-800 Oniks (which can reportedly do M4+ over a distance of ~100km), just much faster.
Yeah, I'm aware of the problems with corrosion of high-temp lead, though this can somewhat be kept in check by limiting the temperature (it hurts efficiency, but might be worthwhile - really depends on the design). It really comes down to materials science and like you say, research on lead cooling has been thin so far. I'd love to see a lot more open-access research in this area.
As for sodium cooling, it has its own problems, but AFAIK it doesn't react explosively in air. It can burn, but if I understand it correctly, the reaction isn't exothermic, so it'll quench itself quite rapidly. Now water is a different story. A sodium-cooled reactor in a potential flood area (ahem, Fukushima Nr.1) is about as dumb an idea as I can think of. Fortunately, the improved thermal efficiency gives you some more leeway to run pumps and pump the water up a hill (like reactors #5 and #6 at the Fukushima Nr.1 plant, which were largely unharmed by the tsunami which totally devastated their lower-sited siblings).
I'm not a fan of light water reactors either, but you need to understand that the public isn't aware of the details and intricacies of reactor design. To them terms which make an engineer cry happy like a little girl, don't mean anything. I mean FFS most of them still think nuclear reactors can explode like atom bombs. They saw Chernobyl and Fukushima, they saw "boom", it's a nuclear reactor, therefore "nuclear boom".
I also think and hope education can change that, but that's a long road ahead and TRU-burning BWRs could work in the interim to help jumpstart that (since we already have them).
the lowest possible temp is -273.15C or -459F, or 0 kelvin. (absolute zero). Increase in flame temp when combusted with air will be approx +10.4C.. (0.04 * 2483K) + (0.96 * 2223K) - 2223K = +10.4K.
You've got a mistake there, 2223K is the flame temp for CH4. Natural gas is 2233K or 10K higher (because it's not pure CH4). The difference, however, is largely inconsequential, it's a 1% increase in absolute flame temperature (exactly like I said), at best (actually 0.44%, but we'll let that go).
+10.4K/(2223K-290K(ore 323C)) = 0.53%(17C) to 0.55%(50C) increase in efficiency to help offset 4% H2's 2.71% reduction in energy content. Since most applications are direct thermal usage(water/hot air/etc) no additional losses will be incurred.
Now hang on, you can't just take the flame temperature and call that your working fluid temperature, that's not how it works in heat engines. Gas-based heat engines (CCGT - the most efficient ones, not talking about ICBs, those have very poor efficiency) use the hot flame to heat a working fluid (typically superheated steam), which is much cooler than the flame itself. I used an 18C coolant temperature (cold water) and 60% efficiency to back-calculate the minimum ideal working fluid temperature (~454C hot vs. 18C cold will give you ~60%). So a 1% increase in absolute flame temperature can at best give you a 1% increase in absolute working fluid temperature, which means your working fluid goes from 454C (727K) to 461C (734K). However, the gains here will be much more modest because you can't just step over a heat exchanger's maximum temperature willy-nilly, or bad things will happen to it, which is why I rounded to 460C (I'm a generous guy, I know :)). So 460C hot vs. 18C cold gives you 60.3%, or about a 0.3% gain.
Now as for "direct thermal usage (water/hot air/etc)", these applications are not heat engines, they don't convert heat energy into work (J -> J/s is a heat engine, J -> J is not), so for them an increase in flame temperature means nothing. For example, it takes the same amount of heat to raise 1kg of water by 1C, regardless if the absolute temperature of the heating source is 100C or 500C, it's still 4.18kJ/kg.C.
Understood, thanks.
The analyses collectively indicate that the two reactors appear to be able to achieve their design objectives: The RBWR-AC provides an equilibrium-cycle breeding ratio of slightly above 1.0, thus providing for a self-sustaining fuel cycle in which depleted uranium is used for the makeup fuel. The RBWR-TB2 is capable of unlimited continuous recycling of TRU while consuming on the order of 10% of the loaded TRU per recycle (after accounting for the newly generated TRU). Most results confirmed the values estimated by Hitachi. Some differences among the predicted reactivity coefficients need to be evaluated further.
This has the potential to be a game-changer if true, as we could simply use existing reactor designs such as the ABWR (of which there are several operating already) to both burn waste and breed fuel indefinitely from U238 feedstock.
Also weird, is Hitachi already has a TRU burning design, the S-PRISM
It's possible they're having trouble getting a dedicated TRU burner design approved and built (there might be little economic incentive and much public opposition to new nuclear plants, no matter the safety of the technology), hence why they might be motivated to try and design fuel that can consume TRUs in standard BWRs, of which Japan already has quite a few.
I agree that burning the crap off is a good thing, but why tack on an expensive piece of extra equipment when pretty much the same effect can be achieved by being smarter about core design? I'm just not seeing the big advantage here.
I never quite understood the allure of ADS. To my eyes it just looks like an exceedingly difficult way of achieving criticality. Given a good design, a reactor will self-regulate by its own negative temperature coefficient, so an external driver isn't strictly necessary and shutdown can be performed by passive systems that are equally dependable as cutting power to the accelerator, e.g. by suspended or spring-loaded SCRAM rods. There is the interesting proposition of not having to reprocess the fuel when running a thorium breeder cycle in order to extract the bred fissile and load it into the core, since one can boost the neutron budget externally, but that needs to be weighed against the pretty steep cost of a high-powered accelerator (in terms of current, not just particle energies) and accelerator reliability issues.
They don't, but the ratio of absorption to fission in the thermal spectrum for them is pretty bad, so that can mess up your neutron budget. Depends on the exact composition, though - each reactor produces a slightly different mix and that makes the TRU content in spent fuel fairly heterogeneous, which complicates reactor design and makes fabrication of reliable fuel fairly expensive (hence why MOX fuel only contains the Pu content, not all the other TRUs and even so it's much more expensive than fresh Uranium fuel).
I don't think they do so in the breeder cycle - their neutron loss margins are fairly thin, hence why most designs propose extracting at the Pu-238 step (unusable for weapons, but great for space batteries). The burner cycle might be better in this regard. Fast reactors are able to do it, they have plenty of neutrons to spare.
What is "neutron saturation transmutation"?
I'm also skeptical of their claims, as it appears to be a thermal-spectrum light water reactor and it's quite difficult to consume TRUs completely in the thermal spectrum, the neutron absorption cross sections are fairly large. Maybe they've got higher enrichment and so shitloads of excess reactivity, so they can afford to lose the neutrons, in which case I seriously hope they have a strong negative temp coefficient. Don't know, would be good to learn the details.
Not sure about the likelihood of meltdown being increased, though. I don't think the decay heat profile of MOX is significantly different from regular enriched Uranium fuel (decay heat melted Fukushima fuel, not fission heat).
What if your point *is* to cause fallout badness.
I'm not convinced of the first-strike capability of hypersonic vehicles. Even at fairly highly hypersonic speeds (M10), the vehicle still takes considerable amounts of time to travel a substantial distance (1000km takes about 5 minutes at M10) - by that time satellite-based detection systems can react and a ground-based counter strike can be initiated (modern ground-based ICBMs can launch in less than 30s, and SLBMs are also an option). At certain distances a good exo-atmospheric missile on a depressed trajectory can strike faster than that. Assuming a 90s boost phase with the final ~10s being used to depress the trajectory arc downwards + a few minutes to travel the 1000-2000km towards the target at easily 4-5km/s. Military solid-fueled missiles have very high thrust-to-weight ratios to shorten the boost phase as much as possible. I think the more problematic aspect is that defending against low-altitude (well, relatively, I mean we're still talking 10-20km in altitude, otherwise the air resistance and shock heating just kills it) hypersonic vehicles in a local theater war scenario can be very difficult - at 10km altitude with the over-the-horizon flight time you only get maybe 30-60s of warning (by my rough calculation at 10km horizon is ~250km away) - depends on radar position and capability, of course.
Your analysis on usability by crazy/unstable countries, I think you're spot on. The big boys have bigger and perhaps more capable toys. It's those crazy wackos who might be tempted (Iran to Israel is only about 1000km, as is NK to Tokyo, so 5 minute strike capability would sound like a sweet deal there).
You seem to have reduced renewables to just wind and assumed that I think the country should be powered 100% by wind, That is incorrect.
I'm not, but I'm looking at the cheapest renewable. There is some hard (dispatchable), but highly limited renewables, like hydro and biomass. These can make some contribution, but it's rather small. If you look at the fastest growing ones, it's wind & solar.
Tepco lie habitually. Their own statements show they don't know what's going on.
Them not knowing doesn't mean you can just make stuff up and fill in the gaps with whatever you like. The linked article is still over a year old and could indicate a temporary condition. Moreover, it's notably light on radioactivity figures for the contaminated water. When you have a look at an article on the guardian which mentions at least some quantitative measurements, it says "quantities of radioactive caesium-134 and -137 in locally caught fish have fallen to levels close to the government-set safe limit of 100 becquerels per kilogram", while noting that it's "scant consolation". I don't know about other people, but knowing that the level of contamination is falling is indication that the situation is definitely improving. And 100Bq of Cs137 (by far the more active of the two) corresponds to concentrations of 0.22 picograms per kg of water (or less than 1 part in one quadrillion), that's pretty close to the detection threshold of the measurement hardware (which is very low) and means you really don't need to be worried at all. There's shitloads of other much more toxic stuff in much larger concentrations in that water that has nothing to do with radiation - honestly, think about the danger rationally.
Hinkley point will get tens of billions in subsidies at the guaranteed rate of £92.5/MWh - roughly double what will be paid for gas, coal, wind etc.
And I don't agree with that. Did you read what I wrote? I said Hinkley Point C was a bad deal.
If renewables are so unobtainable why are Scotland aiming for 100% renewable by 2020 after having beat their goal of 31% renewable by 2011 set in only 2007.
Because you don't understand how the accounting there works. They look at generation, divide by consumption and declare victory. But last I looked, Scotland isn't an island somewhere in the Pacific. In fact a significant amount of that will be pushed south and reimported from fossil fuel generation later when the wind isn't blowing. But since the overall generation divided by their rather limited population (and thus limited consumption) is high, they can declare "100% victory!" Unfortunately, in the big picture, they are hardly making a difference: http://www.gridwatch.templar.c... <- study these graphs, they're not made up. Portugal is probably the same story with Spain, but I'd have look it up (TBH, I'm not familiar with their grid, I know the UK's and Germany's and I've also studied German renewable growth vs CO2 trends - they won't make their 2050 commitment if they continue at the way they've been going since 2004. In fact, by my estimation after they have expanded to 100% renewables in 2055, they'll still be at 40% of 1990 CO2 levels. Can share the raw data, if you like.).
Iceland is 100% renewable electricity, and much of their heating is renewable.
Norway is 99% renewable electricity.
These two are extremely out of the ordinary examples. Both have very low population densities (Norway 1 order of magnitude less than the UK, Iceland 2 orders of magnitude) and both have specific geographies. Iceland is a highly active volcanic island, so it has ample geothermal resources (and I acknowledged that). Norway has lots of water flows, so it has plenty of hydroelectric resources (and I ackn
Or just stick in an simple power limiter which trips a breaker if you go over the limit :) Trouble is, our current energy system originated in the days of yore when we had to consume significant amounts of fuel (and thus cost) to produce a unit of energy. Our energy markets are geared towards it, our grid control is geared towards and people don't like changing systems with lots of investment behind them and which aren't necessarily broken.
If we were building a new zero-carbon grid green field-style, it might well be cheaper to just lose the stupid meters (and spending time reading them, processing them and collecting the varying amounts), put in a simple circuit breaker and be done with it.
I don't see any need to do that, I never suggested that. Just make up some crazy math why don't you.
Oh sure, there's no such thing as a month-long wind lull (by which of course I mean time of very low production). Oh wait, just ignore June.
Note that Tepco itself has admitted that 300 tons of highly radioactive water is leaking.
Your reading needs work again: "Hirose stressed that Tepco does not believe all 400 tons of the water entering the sea is contaminated."
Contrast with what you said: "Are you aware that Fukushima is leaking at least 400 tonnes of highly radioactive water every day." Your link doesn't say it's all contaminated, or that it's "highly radioactive" (which I asked you to substantiate with figures again, and of course you can't).
The point is 0.007km3 is absolutely miniscule compared with hundred of massively larger reservoirs around the world which rand from hundres to thousands of km3 which givens them huge pumped hydro potential.
Go ahead, make the investment pitch and start building. Or you might for a second consider that people smarter than you have thought about this and came to a different conclusion, which is why you're not seeing the projects springing up like mushrooms after rain. Why do you think is that?
That would cost a lot more than £450 billion
Bold prediction, considering that's what a utility building the pilot deployment (= expensive) in the US is paying (where median household income is even higher than in the UK). Moreover, when you buy identical products in bulk, you get volume discounts and volume production benefits - that's pretty normal, even in nuclear power. Even using the hugely overpriced £17B Hinkley Point C, you'd still get ~40GW worth of power onto the grid (supplanting all fossil fuel sources) out of a total of 26 reactors. I don't think Hinkley Point C is a good deal for the good people of the UK and I think the government seriously dropped the ball there, but don't try and extrapolate one government's failure on price negotiation on one project to a whole global industry. If the government were serious, set policy so that industry would be reassured that they won't get whacked over the head by undue regulatory burdens down the line and not limit the selection process for political reasons (it has to be European or nothing!), you'd see utilities even in the UK being able to get much better deals, as others already get in other countries.
Err. The 4% H2 portion burns hotter than other 96% ch4 & c2h6, so the hotter flame temperature is going to help make up for some of the 2.8% loss in energy density for any given volume of gas.
Adiabatic flame temperatures don't mean higher energy release. At best they mean higher heat engine efficiency and you can't just start to run a boiler significantly hotter than it was designed to, or you'll get a rather nasty looking result. Moreover, when you *do* look at the adiabatic flame temperatures of NG and H2 in air, you'll see that a 4% concentration of H2 gives you at best an extra 10C, or about 1% of extra absolute temperature. Using 60% as the efficiency of an idealized Carnot cycle, we see that, assuming 18C cold water cooling, the lowest possible working fluid hot temperature is ~454C. A 1% increase in that gives us ~460C, or an efficiency boost of a whopping 0.3% (ideal best case). In short, not really something to write home about.
Beyond 4%, I expect we'll build a separate underground H2 storage network
Sure, but that'll cost extra, where the entire premise of the original claimant was to utilize the existing gas grid infrastructure (for which we only need to pay for mostly O&M).