Future Energy Pathways

tonnyc

Well-Known Member
You may want to look up the term "decay heat".
It's a known problem. The DOD wouldn't put money into the research if they don't believe that it's solvable.

I'm going by the research done on the HTR by the Idaho National Lab (INL) but I expect any reactor using TRISO fuel is going to have similar numbers, as from what I know decay heat is a product of the fuel composition rather than reactor type. (Though reactor type influences fuel composition, so I guess they're related still.)

The report is for Deep Burn fuel using plutonium but comparisons to UO2 fuel were made and I'm going to be using the UO2 numbers. I don't believe the military will use plutonium-based nuclear fuel on a forward base.

On page 50 of the PDF there is a graph of the decay heat curves of several nuclear fuel. HALEU is supposed to have a higher burn-up rate than LEU, so let's look at the UO2 fuel at 90 MWd/kg.

Going by the graph, the heat generated by the decay products would go down to 1% after approximately 2 hour. The relationship is logarithmic though, so the decrease isn't as sharp at the 10 hour and 100 hour mark.

The article on Project Pele mentions TRISO fuel. TRISO-X is a form of TRISO, but the decay heat rate shouldn't be that different assuming a similar nuclear fuel composition.

We can now cross-reference the Chinese HTR-PM research which use a uranium-based fuel with 8.5% enrichment. This puts the fuel in the HALEU category which is what Project Pele is supposed to use. The burn-up rate at 90 GWd/t is the same as the burn-up rate in the INL report. One just uses kg while the other uses metric tonne. The energy density is stated at 3.22 MW/m3. This is thermal power. We have a core height of 11 m and diameter of 3 m for a volume of almost 77.75 m3 filled with 420,000 TRISO pebbles. A cubic meter volume would then contain 5402 TRISO pebbles.

If we assume a 1% decay heat 2 hour after shut down, a cubic meter of the HALEU TRISO fuel would generate 32.2 kW of heat at the time. Since a cubic meter has 5402 pebbles, that's 5.9607 watt/pebble. Call it 6 watt of decay heat per pebble at the 2 hour mark. The TRISO pebble size used by the Chinese is 6 cm diameter, just a bit bigger than a billiard ball. A billiard ball emitting 6 watt of heat is something you can hold in your hand. I wouldn't do so because of radiation concern (though the silicon carbide casing will stop alpha and beta radiation), but as far as heat, you can handle it. If I interpret the graph in the INL report correctly, at 100 hours it would have gone down to 0.3% (not sure, had to eyeball the logarithmic graph) at which point it's less than 2 watt of heat per pebble.

There is the logistical issue of how to handle tens thousand TRISO pebbles because while each pebble isn't that hot, if you have tens of thousands of them the heat adds up. But this is should be a solvable issue, or they wouldn't entertain the idea in the first place. The DOD will not want a reactor that takes years to remove.

PS: It occurs to me that my use of the phrase "turn it off" may be taken to mean that it can be put into a C-17 immediately after hitting the off switch. That's not what I mean. What I meant by "turn it off" is an intentional controlled shut down taking several hours at least and possibly days. An instantaneous shut down would've been an emergency SCRAM.
 
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vonnoobie

Well-Known Member
For the previously talked about small reactor to support military EV's regardless of how well it would or wouldn't support them I think the biggest issue is placing a nuclear reactor in or near a battle field especially when you factor in drones and the like. Just asking for trouble when a strike against a single target can not only create a humanitarian and environmental disaster but also cripple your forces.

If one day the military regardless of which nation wants to introduce EV's in part or full to the force alongside a clean energy source then it will have to be something that can be easily replaced/sacrificed, easy to use and distributable.

Off hand best thing I can think of is solar mounted onto a 5B MAV https://5b.co/ with which ever battery option you want.

On the civil side I don't see nuclear power being competitive except in nations with a lack of renewable resources. For Australia's case we have that much potential in solar, wind and wave alongside pumped storage hydro we could go 100% clean energy and even supply all of ASEAN.
 

ngatimozart

Super Moderator
Staff member
Verified Defense Pro
I think that this article places the future into context.


On the civil side I don't see nuclear power being competitive except in nations with a lack of renewable resources. For Australia's case we have that much potential in solar, wind and wave alongside pumped storage hydro we could go 100% clean energy and even supply all of ASEAN.
I don't know if pumped hydro is the way to go. How much energy is left over after the water is pumped back up the slope? Water weights 1kg / lt and it requires a significant amount of energy to move 1 cumec (cubic metre) of water uphill. That's 1,000 litres / 1 tonne of water, which isn't a lot when you are talking about hydro projects. The steeper the gradient and the greater the height difference the more energy that is required. So what is the energy budget? And is it economically viable in the long term? I don't know if you could supply all of ASEAN because once you go off coal generation, you may struggle for a while to meet your own requirements.

Here in NZ even with our hydro schemes we will have to find alternate sources of electricity generation and the greenies don't like geothermal generation for some reason. But we have huge potential for that in the Taupo Volcanic Zone. Our biggest problem is going to be the upper half of the North Island with Auckland in it - what's new :cool: It's demands for energy are ever increasing and some would say exponentially each year. A significant increase in geothermal generation capability would certainly help mitigate that demand and offshore wind generation in the Tasman Sea would be something well worth investigating. The technology for that is being used in the North Sea.
 

oldsig127

The Bunker Group
Verified Defense Pro
I think that this article places the future into context.



I don't know if pumped hydro is the way to go. How much energy is left over after the water is pumped back up the slope? Water weights 1kg / lt and it requires a significant amount of energy to move 1 cumec (cubic metre) of water uphill. That's 1,000 litres / 1 tonne of water, which isn't a lot when you are talking about hydro projects. The steeper the gradient and the greater the height difference the more energy that is required.
Not really the point though. Given that solar is potentially able to provide vast amounts of power, but the inability of engineers to get the sun to shine at night, pumped hydro is there to act as a storage battery for spare energy alone. More efficient than Tesla's giant battery in South Australia which (from memory, might be pre upgrade) can provide 30MW for 3-4 hours. And known technology.

oldsig

( coincidentally listening to sparkies finishing the installation of new panels on our roof. Old ones had degraded to near uselessness. You don't get anything for free)
 

vonnoobie

Well-Known Member
I think that this article places the future into context.



I don't know if pumped hydro is the way to go. How much energy is left over after the water is pumped back up the slope? Water weights 1kg / lt and it requires a significant amount of energy to move 1 cumec (cubic metre) of water uphill. That's 1,000 litres / 1 tonne of water, which isn't a lot when you are talking about hydro projects. The steeper the gradient and the greater the height difference the more energy that is required. So what is the energy budget? And is it economically viable in the long term? I don't know if you could supply all of ASEAN because once you go off coal generation, you may struggle for a while to meet your own requirements.

Here in NZ even with our hydro schemes we will have to find alternate sources of electricity generation and the greenies don't like geothermal generation for some reason. But we have huge potential for that in the Taupo Volcanic Zone. Our biggest problem is going to be the upper half of the North Island with Auckland in it - what's new :cool: It's demands for energy are ever increasing and some would say exponentially each year. A significant increase in geothermal generation capability would certainly help mitigate that demand and offshore wind generation in the Tasman Sea would be something well worth investigating. The technology for that is being used in the North Sea.
PSH tends to be in the 70-80% efficiency range. As for the economics if you are using it for short term durations then it costs more ie: less then 4 hours. However if being used for over 4 hours it is the cheapest battery source out there. The most expensive part is the initial capital outlay which is a fraction of nuclear, after that the O&S is quite cheap. For Australia we would have to utilise just 1% of our PSH potential to support a 100% renewable energy market.

As for supplying ASEAN to put it in perspective the sun cable project in NT occupying less then 0.009% of the NT's land area will supply approximately 20% of Singapore's electricity needs. Australia can quite easily produce 1000% renewable energy.
 

ngatimozart

Super Moderator
Staff member
Verified Defense Pro
PSH tends to be in the 70-80% efficiency range. As for the economics if you are using it for short term durations then it costs more ie: less then 4 hours. However if being used for over 4 hours it is the cheapest battery source out there. The most expensive part is the initial capital outlay which is a fraction of nuclear, after that the O&S is quite cheap. For Australia we would have to utilise just 1% of our PSH potential to support a 100% renewable energy market.

As for supplying ASEAN to put it in perspective the sun cable project in NT occupying less then 0.009% of the NT's land area will supply approximately 20% of Singapore's electricity needs. Australia can quite easily produce 1000% renewable energy.
That's ok then. Yes there is quite a lot of potential for solar energy generation in the Top End and elsewhere over in the hot end of WA. I think that the biggest issue with transmitting electricity over long distances is the loss of power over distance. Hopefully there may be a more efficient way of transmitting power than the current metal wire technology.
 

vonnoobie

Well-Known Member
That's ok then. Yes there is quite a lot of potential for solar energy generation in the Top End and elsewhere over in the hot end of WA. I think that the biggest issue with transmitting electricity over long distances is the loss of power over distance. Hopefully there may be a more efficient way of transmitting power than the current metal wire technology.
HVDC cables tend to have a loss rate of 3% for every 1,000 km. So the sun cable project with 4,500km of HVDC should still be able to deliver give or take 86% of the solar produced in Australia to Singapore.

When sending electricity the most efficient way is via DC rather then AC as lower energy loss and lifetime costs between capital and O&S is lower.

Mob actually doing the sun cable project is utilising 5b's MAV and has come out saying it's just the start, that going forward could have many larger projects with HVDC cables spanning from NZ to India and everywhere in between.
 

tonnyc

Well-Known Member
For the previously talked about small reactor to support military EV's regardless of how well it would or wouldn't support them I think the biggest issue is placing a nuclear reactor in or near a battle field especially when you factor in drones and the like. Just asking for trouble when a strike against a single target can not only create a humanitarian and environmental disaster but also cripple your forces.
This vulnerability is of course known and I am assuming that the US DOD does not foresee using it on vulnerable positions. If we see the current way the US Armed Forces operate, their logistical centers are far away from the front line.

I do think that it's way too early to assume EV will be used as a major component of the any forces, so I can't really see it being eliminated from the battlefield. When I try to simulate the role of small reactors, it's basically to provide power for the base, not for the vehicles. The fuel need for diesel generator sets for a base is pretty big and work is continually being done to reduce it. Currently the US Armed Forces is combining solar power with diesel power, reducing the diesel consumption during sunny days. This is considered to be worthwhile.

If one day the military regardless of which nation wants to introduce EV's in part or full to the force alongside a clean energy source then it will have to be something that can be easily replaced/sacrificed, easy to use and distributable.

Off hand best thing I can think of is solar mounted onto a 5B MAV https://5b.co/ with which ever battery option you want.
For EV? By 5B MAV do you mean a solar array made by this 5B company mounted on a medium armored vehicle? That's not sensible from a military POV. In an environment where the threat is significant enough to need medium armored vehicle, that solar array is a weak point. One grenade on it and it's a mobility kill. Not immediately, but the next day. If you go back to base to replace it, the enemy has succeeded in turning you back. You can try armoring it, but that increases the cost and at any rate when the array is open you can't armor it.

No, I have no idea what's a good alternative either. Synthetic fuel maybe, but that has a pretty big logistical footprint too. One still has to ship a whole lot of fuel to where it's needed.

I can see a military base with a lot of solar power arrays providing power to the base and charging batteries at the same time. At night they can use the batteries and who knows maybe most of the batteries can be swapped out with the EV's batteries, but that has drawbacks too. There may not be a single ideal solution, and very likely a multitude of options will be used, adjusted for the situation on the field.

On the civil side I don't see nuclear power being competitive except in nations with a lack of renewable resources. For Australia's case we have that much potential in solar, wind and wave alongside pumped storage hydro we could go 100% clean energy and even supply all of ASEAN.
Good for Australia but although Australia may claim they can supply all of ASEAN, please understand that for various reasons, including energy independence, the ASEAN countries will decline.

PSH tends to be in the 70-80% efficiency range. As for the economics if you are using it for short term durations then it costs more ie: less then 4 hours. However if being used for over 4 hours it is the cheapest battery source out there. The most expensive part is the initial capital outlay which is a fraction of nuclear, after that the O&S is quite cheap. For Australia we would have to utilise just 1% of our PSH potential to support a 100% renewable energy market.

As for supplying ASEAN to put it in perspective the sun cable project in NT occupying less then 0.009% of the NT's land area will supply approximately 20% of Singapore's electricity needs. Australia can quite easily produce 1000% renewable energy.
This, for example. I can tell that Sun Cable is not actually serious about doing this, because to this day they haven't bothered to ask Indonesia about the permission to lay a cable across the length of Indonesia. If they're serious, they'd have asked how much it will cost/year for the rent and factor it so if Singapore ask for a binding quote, they can give it.

Furthermore, the idea that Singapore will be willing to depend on Australia for the majority of their power need is just unrealistic. Singapore will not allow that vulnerability. Even if Indonesia will not threaten to cut the cable when they want something from Singapore, it's impossible to guard a 10,000 km long cable. One ship disguised as a merchant ship carrying the correct tool, and Singapore could be crippled. If Singapore wants renewable energy it would make a lot more sense to deal with both Malaysia and Indonesia and divide their investment. The cable would be shorter, and if one is cut the other one will still be intact.
 
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vonnoobie

Well-Known Member
This vulnerability is of course known and I am assuming that the US DOD does not foresee using it on vulnerable positions. If we see the current way the US Armed Forces operate, their logistical centers are far away from the front line.

I do think that it's way too early to assume EV will be used as a major component of the any forces, so I can't really see it being eliminated from the battlefield. When I try to simulate the role of small reactors, it's basically to provide power for the base, not for the vehicles. The fuel need for diesel generator sets for a base is pretty big and work is continually being done to reduce it. Currently the US Armed Forces is combining solar power with diesel power, reducing the diesel consumption during sunny days. This is considered to be worthwhile.
They aren't that far from the front line, but even if only powering the base why go for the risk of a nuclear reactor at all? Going to require addition specialized personnel to operate it, Dedicated defensive personnel and one strike against it can send the base into the dark hampering the combat effectiveness of the forces operating out of or being supplied by it. Very risky and expensive solution to a none existant problem.

For EV? By 5B MAV do you mean a solar array made by this 5B company mounted on a medium armored vehicle? That's not sensible from a military POV. In an environment where the threat is significant enough to need medium armored vehicle, that solar array is a weak point. One grenade on it and it's a mobility kill. Not immediately, but the next day. If you go back to base to replace it, the enemy has succeeded in turning you back. You can try armoring it, but that increases the cost and at any rate when the array is open you can't armor it.

No, I have no idea what's a good alternative either. Synthetic fuel maybe, but that has a pretty big logistical footprint too. One still has to ship a whole lot of fuel to where it's needed.

I can see a military base with a lot of solar power arrays providing power to the base and charging batteries at the same time. At night they can use the batteries and who knows maybe most of the batteries can be swapped out with the EV's batteries, but that has drawbacks too. There may not be a single ideal solution, and very likely a multitude of options will be used, adjusted for the situation on the field.
Would suggest looking at the link I included, the 5B MAV is not a vehicle mounted unit. It is a quick deployable solar array mostly prewired that allows one to deploy a solar farm in a fraction of the time and cost of most others. Its just standard solar panels mounted onto a unit that literally folds out, rather then installing solar panels one at a time this allows you deploy dozens in one go.

Good for Australia but although Australia may claim they can supply all of ASEAN, please understand that for various reasons, including energy independence, the ASEAN countries will decline.
On one hand yes however if ASEAN nations want to have green power then it will require Australia's energy resources. ASEAN lack's decent wind and solar let alone wave potential to meet their needs let alone future needs that will far dwarf current demand.

This, for example. I can tell that Sun Cable is not actually serious about doing this, because to this day they haven't bothered to ask Indonesia about the permission to lay a cable across the length of Indonesia. If they're serious, they'd have asked how much it will cost/year for the rent and factor it so if Singapore ask for a binding quote, they can give it.

Furthermore, the idea that Singapore will be willing to depend on Australia for the majority of their power need is just unrealistic. Singapore will not allow that vulnerability. Even if Indonesia will not threaten to cut the cable when they want something from Singapore, it's impossible to guard a 10,000 km long cable. One ship disguised as a merchant ship carrying the correct tool, and Singapore could be crippled. If Singapore wants renewable energy it would make a lot more sense to deal with both Malaysia and Indonesia and divide their investment. The cable would be shorter, and if one is cut the other one will still be intact.
A lot of speculation from you their whichs goes out the window when the main backers for Sun Cable are from Singapore and that Indonesia and Malaysia have limited renewable potential. Also the fact that the cable as planned will be the deepest in the world some spots over 1,700m in depth would make it near impossible for more to cut it. Hell it would be easier to knock out a land based cable then one under the ocean.

Should also point out that nothing official would take place towards Indonesia's EEZ as such a path would have to be known before hand for the HVDC so that Indonesia could say yay or nay, Be a bit silly going up to a country "Can I lay this cable? "hmm, Where you going to put it?" ... "I dont know yet, So can I?" The mapping for the Australian waters upto the Indonesian EEZ have been completed already, With the mapping of the Indonesian waters underway at presently.
 

John Fedup

The Bunker Group
I would think any underwater cable that can be reached by remotely controlled vehicles is vulnerable, the Titanic wreck is deeper than 1700m. Could probably be done covertly as well but that is speculation.
 

tonnyc

Well-Known Member
They aren't that far from the front line, but even if only powering the base why go for the risk of a nuclear reactor at all? Going to require addition specialized personnel to operate it, Dedicated defensive personnel and one strike against it can send the base into the dark hampering the combat effectiveness of the forces operating out of or being supplied by it. Very risky and expensive solution to a none existant problem.
Why go for a nuclear reactor? Because the trade-off looks promising. Both China and US are pursuing small nuclear reactors for military use. China plans on using them on their forward bases on South China Seas. The US plans on being more mobile, but it's still a small nuclear reactor for military use. Do they need specialized personnel? Maybe, but that didn't stop them from using nuclear submarines and those need specially trained personnel too. Sure, if you can take it out you can plunge the base into darkness, but bomb a fuel depot and you also take out power from that base. A huge solar panel arrays may not have that vulnerability, but will require more land, which may not be available, and the battery bank is vulnerable to attack.

I consider the people in both the US and Chinese military research department to be smart people. The top brass might be stupid sometimes, but the research guys usually aren't. If they are spending effort on something, I assume the potential is there. Now it could end up a failure. The nature of research is such that sometimes you have to accept failure. But the potential is there.

Would suggest looking at the link I included, the 5B MAV is not a vehicle mounted unit. It is a quick deployable solar array mostly prewired that allows one to deploy a solar farm in a fraction of the time and cost of most others. Its just standard solar panels mounted onto a unit that literally folds out, rather then installing solar panels one at a time this allows you deploy dozens in one go.
My bad. I did look and saw the folding array. But we are a defense-oriented forum and I thought the MAV you refer to is a medium armoured vehicle. You know, just like LAV is a light armoured vehicle. Turns out it's that company's brand name for a foldable solar panel array. Chalk it up to my confusion over acronyms.

On one hand yes however if ASEAN nations want to have green power then it will require Australia's energy resources. ASEAN lack's decent wind and solar let alone wave potential to meet their needs let alone future needs that will far dwarf current demand.
Eeengh. The thing is Southeast Asian countries really really hate energy imports. They consider it to be a weak point that will be exploited sooner or later. It's kinda annoyingly irrational at times but it's how it is. If Australia wants to sell power to Southeast Asian countries, their diplomats will have to be really smooth, because you'll have to get over that political bump. Now, oil and gas imports are a fact, and you can argue that if one is importing oil and gas then importing power isn't a big deal, and you aren't wrong, but at the same time, oil and gas is relatively easy to store and while I can't speak for all SEA countries, I am certain that Indonesia, Singapore, and East Timor will not have sufficient pumped hydro storage while battery banks are too expensive. Well, I'm not against the idea though, but again, it's not as easy a sell as you think it is.

A lot of speculation from you their whichs goes out the window when the main backers for Sun Cable are from Singapore and that Indonesia and Malaysia have limited renewable potential. Also the fact that the cable as planned will be the deepest in the world some spots over 1,700m in depth would make it near impossible for more to cut it. Hell it would be easier to knock out a land based cable then one under the ocean.

Should also point out that nothing official would take place towards Indonesia's EEZ as such a path would have to be known before hand for the HVDC so that Indonesia could say yay or nay, Be a bit silly going up to a country "Can I lay this cable? "hmm, Where you going to put it?" ... "I dont know yet, So can I?" The mapping for the Australian waters upto the Indonesian EEZ have been completed already, With the mapping of the Indonesian waters underway at presently.
The easy route for an ultra high voltage power cable from Australia to Singapore is start from around Darwin, go into the Lombok Strait, and straight along the Java Sea toward Singapore. Java Sea is shallow and well-mapped. The Lombok Strait is deeper at 1000+ m but is also well-mapped. Laying down a cable there is easy, and given the shallowness of the Java Sea, accessing the cable for repairs is easy, at least across that sea.

If you want to avoid as much of Indonesia's territory as possible, you have to go west into the Indian Ocean. This is deep and it seems you consider it an advantage. Okay. But that route must pass through the Sunda Strait. This is a shallow channel of at most 100 m depth at points and an average depth of 20 m. Lots of ships going to/from Jakarta passes through this strait and we have had fiber-optic cables cut just because a ship's anchor just happened to hit it. The power cable then still have to snake through the Java Sea toward Singapore.

Incidentally, the amount of traffic passing through the Sunda Strait is also a reason why Sumatra's and Java's grid aren't connected. Cost is a reason, of course, but the risk of spending all that money only to have the cable cut by a stray anchor makes them really hesitant.

The Sun Cable's business case is really iffy. If I were Singapore and I want clean energy, then the sensible thing is to split whatever money I'm prepared to invest in that cable and spend it on solar power projects in Malaysia and Batam island in Indonesia. If Batam's too small, lay an underwater cable to Sumatra and build the solar power project there. It's only a hundred km. West Australia may have more power potential, but that long cable is a massive time and money sink.

If I were Australia and I want to sell clean energy, the sensible thing is to sell to Indonesia. Lay a cable from Darwin to Bali island. Bali is connected to Java already and Java's demand for power is multiple times Singapore's. If you can outcompete coal power, and the assumption is that solar power can, and you have lots of power, and again the assumption is that West Australia have a massive surplus, then you'll make more money selling to Indonesia with less than half the cable investment. Again, there'll be a lot of political resistance but if you can go cheaper than coal they'll all shut up eventually.
 
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