Monday, April 20, 2009

AP-1000 Reactor being built in China - current summary and possible problems

In a pressurized water reactor, there's a separate reactor coolant loop that passes heat through metal tubes, boiling 'feed water' in the steam generator, and the steam spins the turbine that makes electricity. The primary coolant and the feed water/ steam do not come in contact.

In a boiling water reactor, the reactor directly boils the water that spins the turbine. One big advantage of this is cheaper construction.

Both types 'burn' Uranium to generate the heat that boils the water. Pressurized Water Reactors simply have an additional segregated loop of water.

The Chinese AP-1000 is a conventional pressurized-water reactor. It's built mostly from existing Westinghouse components which Westinghouse had type-approved by the US Nuclear Regulatory Commission, so that multiple identical units could be built without going through a full design review for each one. So far, nobody has ordered one. Until now. Most US reactors are unique designs, which is a headache. France has 34 reactors of the same design, which has cost and maintenance advantages, although there's been at least one common design flaw found. Westinghouse is no longer a US company. It's owned by Toshiba.

It's a 1.2GW plant. The current order is for four reactors, for 8 billion dollars. The price is expected to fall to about 1 billion per reactor. China has a goal of building 100 reactors by 2020. IF the USA built that many, it would cut power plant greenhouse gas emissions by 30%, or the equivalent of nearly a million windmills.

At a cost of $5.85 billion [google.com], and assuming a lifetime of 40 years, an interest rate of 6%, this nuclear plant will have an annual mortgage of $389 million [google.com]. With a nameplate rating of 1100 MW [mediaroom.com], if it runs 92% of the time [nei.org], it will produce 8.9 billion kWh per year [google.com], so the capital repayments will amount to $0.044/kWh [google.com], assuming it doesn't go over budget. Assuming an optimistic cost for fuel around $0.005/kwh [world-nuclear.com], this gives a total cost of $0.049/kWh, neglecting the cost of maintenance, waste disposal, and any risk of contamination or weapons proliferation.

Now let's look at a new wind farm. A 50 MW wind farm would cost around $96 million [google.com] (at $1923/kW [doe.gov]), which yields an annual capital repayment of $7.5 million [google.com] (assuming a lifetime of 25 years). If the plant runs at a 35% capacity factor [awea.org], it will produce 153 million kWh per year [google.com]. So the total cost will be $0.049/kWh [google.com].

So, which would you rather spend $0.049/kWh on -- a nuclear plant that might go over budget, might leak radiation at some point during its life, whose waste will need to be carefully controlled and permanently stored somewhere that hasn't yet been identified; or a wind farm whose costs are much more certain and which comes without all those ancillary risks?

Yes, any individual wind farm will not provide a firm supply of power. But if a lot of wind farms are used, and they are combined with solar, geothermal and other renewable resources, they will provide a fairly stable power supply. There is also a lot of potential for reshaping electricity loads to match the supply of power (e.g., recharge electric vehicles when the wind is blowing or the sun is shining). And finally, if you must have a firm supply of power, you can convert a wind farm into a completely firm supply (at 35% of its nameplate rating) by spending about 10% extra and building rarely-used natural gas peaker plants ($634/kW [doe.gov] * 35% = $222kW).

IMO: Clearly India must consider the feasibility, appearance and practicality of wind power as well as nuclear power. The big wind power plants in California suggest the possibility of many problems with wind power. And Chernobyl and Three Mile Island we don't want either. But we certainly need much more energy.

Comments:
AP1000 is 1154mw, it does not cost 5,85bn and the average lifetime of a nuclear reactor is now around 60 years.

Windmills do not run at 35% on average, for land based windmills the number is typically closer to 20%, and the average is really dishonest to use here, especially since wind power tends to generate a lot more power when the load is typically low(ie. summer)
 
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