Grid and Electric Vehicles

Ok, once we have small, modular reactors ready to be sited, we can discuss them. But, until they are actually available and not just an idea on a Wikipedia page, we can ignore them as options for now.

If you want to discuss "the future", we can talk about $0.01 per kWh batteries and total renewable energy costs (including storage) of $0.10 per kWh.

A 1 m long 1 mm2 copper wire has a resistance of 17 mOhm, thus 1 km has 17 ohm resistance and the total loop resistance 4500 km (x2) cable is 150 kOhm. Running the ordinary 1 A/mm2 current density through the loop and 150 KV is lost. Using 0,5 A/mm2 current density the total voltage loss will drop to 75 kV, which would be bearable for a 1000 kV system.

If you would like to run 1 GW through the system, the current needs to be 1000 A, so each cable needs to have a 2000 mm2 cross section at 0.5 A/mm2 (50 mm diameter)

The copper density is 9 kg/dm3 thus 18 kg/m or 160000 toms for the whole system. Assuming 5 euros/kg, the total cost of raw copper would be 800 million euros. Making HV cables of it would multiply the price several times.

Actually two KLT-40 icebreaker reactors are mounted on the Academik Lomonosov barge, which is currently parked at some town on a Siberian river.

There is a lot off math involved there.

I do not know how it will change things but if 60 HZ or some other AC frequency is used on very long wires the lines act like a radio frequency transmission line and other factors may need to be added in.

It's not that the wires become radio antenna. Rather there is an effect called the skin effect, where the current is concentrated near the surface of the conductor. The work around, is to split the single fat cable into multiple smaller diameter cables. If you look at high voltage power lines, you will often see each of the three phase conductors spread by triangular spacers with three wires. The three smaller wires carry more current than a single wire with the same copper, because of the skin effect.

afaik the big overhead lines are usually aluminium,

I stand corrected. How is that relevant to what I was saying? The same principles apply for the skin effect.

as it say right there on the page, you see everything as an attack?

That may be an issue, I don't know, but another is certainly to reduce the E-field strength near the conductors, to reduce corona.

Jeroen Belleman

WTF??? I have no idea what you are talking about. I asked you how the page is relevant and you say I think I'm being attacked. People post links expecting others to dive in and read it, without knowing anything about how it is related to the topic.

Call me lazy, but I'm not reading an entire wiki page when I have no idea why I would want to read it. I think you are being lazy to not explain WTF you are trying to say.

So how about it? What is your purpose in providing the link?

From what I've read, that is not much of an issue with the wires themselves, in relation to their dimensions. The problem is the tiny blemishes that reduce the radius and create higher fields at individual points. That's why they file and polish any blemishes on the wires, often from handling in the field. That was some time ago, voltages may be higher now and even the polished wire may have issues with corona, but what can you do about that?

Yes, which is why long distance interlinks links are DC.

And there are bunch floating around in nuclear submarines and US nuclear powered-aircraft carriers. They may be modular but they aren't sold off the shelf.

Not to mention the second hand market in modular reactors from nuclear submarines.

There are a few things why very long (>1000 km) AC systems are not practical.

At 60 Hz the wavelength is 5000 km, so definitively the line must be treated as a transmission line (characteristic impedance, line termination). This may limit the voltages and currents to get the impedance levels right. This can be used only for a point to point connection, no extra insertion/extraction points along the line, since the phase is different along the line. Thus not useful for network building, only for trunk lines.

The capacitance between phase and ground becomes huge. The situation becomes much more severe if underground or undersea cabling is used instead of overhead lines. On a too long connections all real power is used to charge and discharge the capacitance during each AC cycle and no real power is available at the opposite end of the line.

At 50/60 Hz all power us packed in the skin depth of about 10 mm. Very little current is carried by the center of a conductor if more than 20 mm in diameter is used. The resistance affects only in the skin dept. Thus the resistance is greater on AC than on DC. To avoid the skin effect, multiple conductors each about 20 mm in diameter are placed

10-50 cm from each. This is reasonable on overhead lines, but will increase further the capacitance on underground cables.

For all these reasons extremely long DC links are used especially when underground or undersea cables must be used.

There is no phase issue, no capacitance issue and no skin effect.

Older SCR based HVDC systems can be used, but also mainly usable for point to point connections, since the line voltages must be reversed to transfer power in opposite direction.

Modern IGBT VSC converters do not require polarity changes and multiple terminals can connect to a line, forming truly large networks suitable for renewable sources.

Yes, I hear business is "booming"!

Nuclear reactors don't explode. They may melt into an intensely radioactive puddle of material that is thermally warm, but Chernobyl seems to be about as bad as it gets (which wasn't exactly innocuous). The point I was making was that the business doesn't actually exist - that kind of reactor isn't designed to be recharged so there is no second hand market. Modular reactors designed for civilian applications might well be designed to be recharged. I don't know anything about that at all. I don't know much about Rickover's nuclear reactors either, but nothing has ever been said about re-charging them - the design brief was to keep them compact, so rechargign would be a bug rather than a feature

You never did have much of a sense of humor. Whatever.

Really? If that was intended to be a joke, your own sense of humour isn't exactly impressive. I get my fix of comedy from the New Yorker which goes in for more subtle comedy.

To my understanding there are multiple icebreakers with KLT-40 reactors in Russia. I have no idea how much different these are compared to nuclear sub reactors.

Anyway putting the reactors on a barge makes it possible to tow them to the middle of nowhere (e.g. Siberia) and let them produce heat and electricity for three years.

After that tow the barge back to civilization (Murmansk ?), replace the fuel and tow it back to the middle of nowhere for the next three year period.Thus very little infrastructure is needed at the middle of nowhere.

Apparently they have tried to sell these barges also to other countries without success so far.