These are very interesting. However, I think Americans would be more accepting of fewer larger reactors vs. more smaller ones.

These units do not need to consume any water. They can if they were operated like old steam locomotives. They also can if some water were evaporated to cool the consenser water as many steam power plants do. Many steam power plants pump cold water into their system from a river or lake or ocean and pump it right back again. They do use but they do not "use up" the water. Many people try to make this later use of water into a big issue because they do not understand that the water can and is returned to be used by cities and farms or to flow into the sea. The water in such lakes or streams is not heated substantially and cools off soon most of the time. Before humans were on the earth the water flowed uselessly down the streams and was wasted in the seas.

Cogeneration avoids the need for this cooling water. No natural gas should be burned for electricity except in cogeneration units at homes or businesses. TATA should now build a cheap cogeneration unit, The TATA NANOCOGEN.

There is very little difference between many small reactors at one location than one large one except enormous increases in reliabilility and redundantcy. As many as are needed can be shut down to deal with low load. If one of ten needs repair or refueling or replacement, then nine are still functional. Three of the four reactors at Chernobyl were restarted and operated for many years after the one exploded because operators disabled the safety systems until too late.

Thousands of people are employed at a large reactor site and many small reactors at the same site would not greatly increase the labor needed because of automation.

The first of two reactors at Three Mile Island was put back into service after modifications were made so that it did not fail as the second one did. One explanation of the Three Mile island failure was that it was rushed into service to get tax credits that year. A valve actualy did fail, but after that and before that many mistakes were made. It was obviously too big. Four smaller ones would have been less costly in spite of low efficiency. Several large steam turbines have failed and their high efficiency would never have made up the losses of the failure that took months or years to repair. Infact, the losses may have been so high that the higher efficiency of all such turbines together may not have made up the losses.

Steam power turbine builders have forgotten that redundantcy may be better than efficiency. Efficiency has not been the concern of the solar energy industry since the solar cell was invented; convenience has been the driving force with some emphasis on hope for more efficient solar cells. If the solar electricity business were concerned with efficiency, then large arrays of solar cells would not be sold anymore, and the parabolic small systems of Infinia would be promoted for small homes and businesses and the larger ones for large scale production. Mass production of the Infinia type machine can reduce its costs greatly. It actually may be too large. A solar sterling system gives very high efficiency compared to solar cells.

As it is in solar energy, efficiency is not very important in the fission industry, and only about one pecent of the energy available in natural uranium is used in the US. Carlo Rubbia proposed the thorium fueled Energy Amplifier fission reactor and in the cost analysis, the cost of the fuel was a very small part, less than one part in twenty, of the production cost of the electricity. Even Coal represents only about a fourth of the cost of electricity from coal fired power plants.

The change away from hydride is disappointing. Actually the electrical efficiency is not a concern if the reactor were used for steam heating. Many such units could be buried about a hundred feet below any part of NewYork city and feed the steam system to save a lot oc CO2. The fact that hot water rises or other means can be used to bring the heat from a depth where a Chernobyl explosion would not disrupt pedestrians. Foam glass can be used as a very long life protector and insulator of steam pipes and can be made from recycled glass.

Individual large buildings anywhere can use one of more of this size of energy converter to provide for both heating and cooling. Units, ordinarily used for geothermal electricity, may be used by these buildings to make some electricity as well. ..HG..

This reactor design has not yet been submitted to the NRC. The designs currently before the NRC are, in reality, updates of existing light water reactors in service throughout the US. The designs currently before the NRC are taking 3 or more years to get approval. This design is far more challenging than a conventional LWR, despite its small size.

If they are going to be making deliveries starting in 2013, it will be to markets outside the US and without NRC design certification. A US based company trying to market an uncertified design is not a gold plated business plan.

Bill

Hopefully someday we'll be able to solve the nuclear waste problem. I'd like to see it taken up into space via the space elevator the Japanese and others are working on, then sent into the sun with the nuclear powered ship the russians are working on.

http://news.yahoo.com/s/ap/20091029/ap_on_sc/eu_russia_nuclear_spaceship

http://news.search.yahoo.com/news/search?ei=UTF-8&c=&p=space+elevator

"The HPM is small enough to be manufactured en masse and transported in its entirety via ship, truck, or rail..."

...which means, it's only a matter of time before somebody steals one for mischief.

The advantage of much smaller nuclear reactors is that they can be mass produced at a much lower cost and installed very close to where the power is required, limiting loss and the use of very expensive long power lines.

Aluminium and steel (and similar) plants could have their own on-site small nuclear power plants and not even be connected to the national grid.

A few well located underground N-plants could supply all the power a small/medium city need without overhead cables. The face of America would change without all those power lines, poles and towers.

However, the not in my backyard fight will last a few centuries in the land of the 10 million lawyers and lobbies.

OOPS! "the thermal efficiency" should read electrical efficiecy (36%)

Henry,

Lets hope the water and pumps hold up for the cooldown phase. Then grt it back to the factory before it heats up again.

"which weighs 50 tons, would operate like a battery: it would be slotted into place in a power station built by an undisclosed partner company, connected, and generate power continuously for seven to 10 years without refuelling. Then it would be disconnected and left to cool down for up to two years (with water) before being removed and returned to the factory for dismantling"
------And refurbishing Arn.

Sandia's sodium-cooled fast reactor could use U-238 (with a starter load of reclaimed reactor plutonium), but not Hyperion.  Hyperion is a thermal-spectrum reactor and requires U-235 or U-233.  I expect that it would take some time to design a Hyperion based on the thorium-uranium cycle, so U-235 is it for now.

Hyperion is going to have a huge market in areas dependent upon oil for electric generation (like Hawaii).  Oahu could use a few dozen Hyperions (~1.3 GW peak consumption) or ten or so of the Sandia reactors.  Hyperion would also play well where there are industrial consumers of low-pressure steam.  A $1/watt steam supply good for 7 years comes to a bit over 1.6¢/kWh for heat, or under $5/mmBTU.  That's competitive with natural gas, and no market risk.

We should consider what will happen when and if Hyperion and any of their customers go bankrupt and aren't around to dig up/recycle/decommission these units. Say a steel mill buys one, goes bankrupt, it sits in a brownfield for a few decades--whose responsibility is it? Then say there's no Hyperion to deal with taking it back. Is it now the DOE's problem? Do they even know it's there? Imagine more decades pass, etc. Perhaps a terrorist group finally digs it up when no one's looking. Is there anything worth stealing or processing inside? Anything dangerous at all? That should be the question. Maybe someone here can answer it. If not, then I'm fine with it.

We can at least keep track of the nuclear power stations in the world, precisely because they *can't* fit on a flatbed truck. Thousands of these units in private hands scattered all over the world may not sound that bad now, but think a hundred years ahead when we could easily have lost track of them all, just like we no longer know where all the former gold mines are that are leaking arsenic into the groundwater in California. The whole proposition seems pretty dubious to me, especially when there are simpler alternatives, like solar approaching a dollar a watt.