This kind of massive improvement should reduce costs of nuclear even further.
The Chinese build them for around $1565kw, so with this you might get near to $1000kw, and if you used annular fuel even lower.

I have been waiting for this. It's big.

Unfortunately, it appears to me that this probably can't be retrofit to existing nuclear powerplants. Anything which depends on e.g. boron in the coolant to regulate the reactivity isn't going to work with such a radical change in the coolant. Being able to hike the efficiency and output from existing plants by such a large amount would be great, though.

The real issue, though, is what you get when you use this with combustion fuels. Conventional gas turbines operate at turbine inlet temperatures up to 1360°C. If the same could be used with SCO2 as the working fluid, the thermal efficiency could go well over 60%.

EP:
For natural gas I prefer the idea of pumping it to the home or office, then putting it through a fuel cell. Panasonic and others reckon they can bring the price down to reasonable levels by 2013.
That way of course the waste heat gets used to heat water or for space heating.
We might be able to get a 30% or so better use out of our natural gas that way.

Also in the category of "hmmmm, interesting" would be a serial electric airplane! Or perhaps direct drive!

Liquid-metal and molten-salt reactors are specifically mentioned in Vaclav Dostal's PhD thesis on SCO2 turbines.

Dave, I believe the H2O byproduct from CH4 combustion in a system designed along the lines of an SCO2 turbine would be an issue at the cold end; you'd wind up with some very different specific heats on opposite sides of the regenerator, causing pinch points and losing efficiency. This suggests that methane would be best used in something else anyway.

What the supercritical cycle does is exploit the very high specific heat (and low ratio of specific heats, Cp/Cv) in the region of the point of criticality to reduce the back-work of compression. This has other complications specifically related to regeneration/recuperation (the specific heat of the fluid leaving the compressor is much greater than the same mass-flow of fluid at higher temperature coming from the turbine) but there are ways to deal with this, e.g. the recompression cycle.

High efficiency is not needed in a nuclear power plant because even with the costs of fabrication of fuels there is only a small fraction of the power cost as delivered that is due to the cost of fuel. When the first power reactors were proposed the power industry executives knew that if coal were delivered to existing power plants at no cost, the cost of electricity at the consumer would be reduced by only 25 percent.

The efforts to build larger and larger nuclear power plants to increase the efficiency of the turbine and generator has only resulted in much higher costs.

The highest costs result from lies told about the dangers of nuclear radiation by people who don't know that every living thing has always had radioactive potassium in every cell, and that cell mechanisms exist to repair damage from this built in radioactivity as well as the radioactivity always coming from the universe and the earth. Much more damage is being done to the cells by the large concentration of oxygen in the air that gets into the cells and the iron that is necessary in very small amounts for metabolism. The cells also repair this damage most of the time. If the damage to a cell is not repaired, it dies or is killed most of the time by its neighbors. Cancer almost never happens and tumours are almost always caused by something else besides nuclear radiation, and it can never be shown that a particular tumour was caused by radiation or if it was caused by natural radiation.

Most of the atoms of potassium in live and dead things that were alive are not radioactive but modern technology allows them to be replaced by mostly radioactive potassium atoms because the body is constantly changing them. It is likely that such an action would kill the test subject which would show that people can have an average life span even with a few but not many radioactive atoms in them.

If the subject did not die soon with mostly radioactive potassium atoms in it, It would show that the cells do good repairs. People and animals live in some naturally highly radioactive areas without obvious damage. One mold is known to grow near intense radiation in power plants, and it likely feeds on it like plants do on sunlight.

All rocks and soil have some level of radioactive natural uranium and natural potassium in them, so if a few extra atoms are added as they are with any good fertilizer it is not a significant risk. This also means that any radioactive material could be mixed into such fertilizers or spread separately on the ground if the additional radiation provided was a small fraction of a percent. If the highly energetic cosmic rays don't kill you and they don't, then a few rays from added materials in the ground will not either.

Natural or synthetic Radioisotopes can be immediately be made non dangerous by very highly diluting them in water and spreading them out on the land or the sea where they join the far more common all natural radioisotopes; Live things demonstrate this all the time by coexisting with the about 50 potassium atom explosions per second per kilogram of body weight and the additional rays from space and rocks and soil and plants and dogs and cats and people.

CANDU reactors are among the smallest and fastest standard reactors to build and they should be ordered until even smaller standard ones become available. They can operate on a thorium cycle to get rid of long lasting transuranic isotopes including surplus materials from weapons and other reactors.

Fuel reprocessing has been shown to be necessary because the US government has failed to use the used fuel funds according to the signed contracts. The US WIPP can be used to reliably store the small volume of fission products produced every year. Once reprocessing factories are in full use, the costs of operating them can be reduced by experience and cheaper processes. They are necessary for thorium cycles.

Every nuclear power site should order one or more of the smaller reactors proposed for delivery, and they can be used for emergency cooling power all the time for the big reactors. Excess power from them is fed into the grid during normal operation for more revenue.

..HG..

Henri Gibson, when will you stop to pollute this nice site with your disinformation and outdated technology promotion like zebra battery and Candu reactors ?

For natural gas I prefer the idea of pumping it to the home or office, then putting it through a fuel cell. Panasonic and others reckon they can bring the price down to reasonable levels by 2013.
That way of course the waste heat gets used to heat water or for space heating.
We might be able to get a 30% or so better use out of our natural gas that way.
Davemart still trying to shoehorn fuel cells into every discussion. Instead of pumping natural gas inefficiently to every home then using it in a fuel cell why not just use it in a combined cycle generating plant at higher efficiency and transmit the power through existing lines?

He's claiming 30% energy recovery from NG using a fuel cell with waste heat recovery yet combined cycle generating plants can easily beat that.

i am wondering why CO2 is used. if compared to water, CO2 specific heat capacity is less and the constant R for the ideal gas law is also less.

CO2 absorbs less heat and it also expands less if compared to water

for CO2 to be closer to liquid state, it needs to be cooled or pressurized. this may not be preferable.

water on the other hand can be manipulated easily to exist in either liquid or vapor form. To maximize heat absorption, water should exist in liquid state. Once the time comes for it to do work, it should be in gaseous state. Of course, as it changes state from liquid to gas, latent heat of evaporation, this will further absorb the excess heat.

"That's an advantage. Steam turbines have to be enormous to handle the large volumes of fluid, which makes them expensive. They are also much less efficient. " well i beg to differ, water with very high specific heat capacity and high gas constant R, it is the other way around actually. Furthermore, density of CO2 is always lower than water and many of the thermodynamics equation uses m (mass) thus it does make a big difference.

i disagree with you, steam expansion in heat engine is only needed to move a turbine or piston. Piston and turbine sections are normally confined in a small volume which is easy to manage. When work is not needed, water should exist in liquid form.

Try doing so with carbon dioxide. You need a lot of pumping work to move the carbon dioxide around.

if i can remember when i was studying engineering in Boston, brayton cycle normally has lower efficiency. it's not a surprise why nuclear and coal power plant uses water as the working medium.