29 February 2008

Promising Nuclear Energy: An Important Bridge Into the Unlimited Energy Future

Nuclear fission offers an economical, low-pollution, highly efficient CHP energy path into a future where prices for oil and gas are uncertain. Nuclear power is reliable baseload power--unlike wind and photovoltaic which can fail due to weather (as in Texas). Within the next few decades, we will have reliable large-scale geothermal, large-scale utility energy storage for renewables, large-scale biofuels and synthetic fuels (Venter), and perhaps large-scale nuclear fusion. But until then, nuclear fission provides the bridge.

Two of my favourite blogger-Brians, Brian Wang, and Brian Westenhaus, have once again posted on an important topic at roughly the same point in time.

Brian Westenhaus looked at multiple nuclear options yesterday.
China ordered four Westinghouse AP 1000s, which should kick off a reduction in per plant costs, but the manufacturing capacity at Westinghouse might limit the benefit. South Africa’s Pebble Bed Modular Reactor is expected to offer a new step in safety, economics and proliferation resistance.

Today the leader must be the Westinghouse AP 1000 with several design certifications in hand now. The design offers the lowest installed cost projections of the current group at $1200 per kilowatt and a 36-month construction schedule. Those numbers would put power on the grid below US$0.035/kWh. That’s cheap power.___NewEnergyandFuel

Only two days before, Brian Wang looked at an even larger array of nuclear options:
A larger US design, the Modular Helium Reactor (MHR , formerly the GT-MHR), will be built as modules of up to 600 MWt. In its electrical application each would directly drive a gas turbine at 47% thermal efficiency, giving 280 MWe. It can also be used for hydrogen production (100,000 t/yr claimed) and other high temperature process heat applications. Half the core is replaced every 18 months. Burn-up is up to 220 GWd/t, and coolant outlet temperature is 850°C with a target of 1000°C.

The Westinghouse AP-1000 has received several design certifications. Overnight capital costs are projected at $1200 per kilowatt and modular design will reduce construction time to 36 months. The 1100 MWe AP-1000 generating costs are expected to be below US$ 3.5 cents/kWh and its has a 60 year operating life.

Another US-origin but international project which is a few years behind the AP-1000 is the International Reactor Innovative & Secure (IRIS). IRIS is a modular 335 MWe pressurised water reactor with integral steam generators and primary coolant system all within the pressure vessel.

...The Remote-Site Modular Helium Reactor (RS-MHR) of 10-25 MWe has been proposed by General Atomics. The fuel would be 20% enriched and refuelling interval would be 6-8 years.

Another full-size HTR design is Areva's Very High Temperature Reactor (VHTR) being put forward by Areva NP. It is based on the MHR and has also involved Fuji. Reference design is 600 MW (thermal) with prismatic block fuel like the MHR. HTRs can potentially use thorium-based fuels, such as HEU or LEU with Th, U-233 with Th, and Pu with Th.___NextBigFuture
Anyone interested in the future of nuclear power should go to both of the articles above and check out the figures and the links.

The modular helium reator (MHR) seems to offer scalable, safe ("meltdown-proof") power suitable for remote locations requiring reliable, plentiful heat and power (CHP).
Conventional, low-temperature nuclear plants operate at about 32% thermal efficiency. GT-MHR power plants can achieve thermal efficiencies of close to 50% now, and even higher efficiencies in the future.

• 50% more electrical power from the same number of fissions.

• Dramatically lower high-level radioactive waste per unit of energy – today’s reactors produce 50% more high-level waste than will the GT-MHR.

• Much less thermal discharge to the environment. Plants can use air cooling, which allows for more flexible siting options.___Source
A competing technology to such modular reactors as MHR, is the "nuclear battery" approach, which is also suitable for CHP--combined heat and power.

Here is more on small nuclear reactors.

Modular, scalable, safe, reliable nuclear reactors are suitable for many locations. More on that topic later.

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Blogger Paul said...

"Today’s reactors produce 50% more high-level waste than will the GT-MHR."

What will happen to the waste generated?

Studies that are now being financed such as "Life prediction of civil structures and their components", tell us that we still don't enough about the lifetime costs of storage compartments for nuclear waste.

The energy costs of regular renewal (every 300 years) of civil structures that protect waste compartments might be higher than the energy generated by the original nuclear fuel.

Monday, 26 October, 2009  

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