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Tuesday, December 18, 2007

Iranian Reactor built by Russians

Pardon me while I leave the topics of Faith & Politics to wax philosophical about nuclear power.

CNN reported yesterday that Russians were shipping enriched uranium to Iran for its nuclear reactor that was built with the help of the Russians. I was concerned because I don't trust Russians and nuclear power. For example, the Chernobyl reactor was moderated with graphite and cooled with water. That is, the graphite is used to slow down the neutrons so they can cause fission and therefore cause power to go up. The water takes the heat away. So that when there was a power spike and the water boiled off [no more cooling] the power could continue to go up [graphite moderated] until all of the fuel and graphite melted into a big "elephant's foot" underneath the structure. In an American built reactor, the water moderators the reactor, so when power goes up and there is less water (or less dense water) the power is naturally turned down, without moving the control rods.

It appears that the Iranian Reactor is moderated and cooled by heavy water. [1] I didn't think heavy water reactors required enrichment, and neither does source [1], so maybe the reports of enriched uranium really means refined uranium ore. Enrichment usually means increasing the concentration of U-235, which is fissile, as compared with other non-fissile isotopes of Uranium.

The reactor is also very small by U.S. standards. A couple places say that it is 40 MWth. [1], [2]. Compare with Oyster Creek in New Jersey that is 636 MW(e)/1500 MWth, or Palo Verde, with three units each twice the size of Oyster Creek. Megawatts Thermal is the power generated by the reactor, megawatts electric is the power sent down the transmission line. (You should follow the OC link to see how wonder nuclear power is; the website has pictures of daises.)

So, I'm less scared about the Iranian reactor than I was initially when I heard the Russians were helping to design. It seems to be strangely small, but I guess I understand how it is their first reactor. And it does make sense to me that they would want to generate electricity with cheap clean nuclear power and continue to sell oil to the West.

5 comments:

Matt Dick said...

Those are dandelions.

JimII said...

My bad.

Matt Dick said...

Uranium-enriched dandelions. Wouldn't it be nice if all dandelions could be enhanced by the local uranium-enriched groundwater?

JimII said...

Hey now! There is nothing uranium in the groundwater around Oyster Creek.

Actually, while I was there a celebrating was running a drive to collect children's baby teeth to look for evidence of contamination from the plant. I think they will not find any. That said, the discharge of the heat exchanger keeps the flow warm and thus attracts fish. So many that if the plant shuts down in the winter time the temperature change kills the fish--> because the plant stops heat poluting the river.

Anyway, guys fish at the plant discharge. Now, I'm a huge advocate for nuclear power, but I don't know if I would eat fish from the outlet of the heat exchanger. I mean, it's probably fine, but why push it?

Matt Dick said...

The big thing I've learned in the last 15 years about nuclear power is that it's basically a toxin, like any other. It works differently, and I guess it lasts longer, but your uranium cancer is no worse than your toluene cancer.

I don't fear it at all. Draining lakes in the ex-Soviet Union probably killed as many people as Chernobyl, and that was as bad as nuclear power has ever been. But not fearing it, and eating Isotopically Enhanced Bass are two different things.