Nuclear vs. Other Sustainable Energy

[evacek3]

I'm a freshman at UofI and am in engineering physics and we're given the option to take an elective option which is basically like getting a degree in physics with an emphasis on a specific area. Since I kind of want to go into sustainable/renewable energy I was wondering if I should take a broad approach which would cover many avenues of new energy or if nuclear energy will dominate the industry to the point where getting an emphasis in say solar or wind or geothermal will be a waste of time.

 

[mal4mac]

To quote Bob - the answer my friend is blowing in the wind.

It depends so much on politics and "freak events" that who can say? No one expected the tidal wave that wrecked the Japanese reactor. There might be another Three Mile Island that some politician might use as an excuse to cut back on the nuclear programme. Then again, solar might start to look look like a bad investment, so that nose dives. Politicians seem to be hedging their bets by advancing on all fronts, I would do the same until it comes closer to applying for a job... You'll probably find that at the time you start looking for jobs you can get a job in the "current trendy" area with *some* experience in that area, so get *some* experience in many different areas...

 

[Astronuc]

I'm a freshman at UofI and am in engineering physics and we're given the option to take an elective option which is basically like getting a degree in physics with an emphasis on a specific area. Since I kind of want to go into sustainable/renewable energy I was wondering if I should take a broad approach which would cover many avenues of new energy or if nuclear energy will dominate the industry to the point where getting an emphasis in say solar or wind or geothermal will be a waste of time.

Nuclear will probably not dominate the energy mix in the US, at least not in the near term.

There is a place for renewable energy: wind, solar, geothermal. The challenge is to get the most out of each technology with minimal detrimental impact on the environment.

 

[turbo]

There are virulent opponents to wind power in Maine, claiming that the wind turbines ruin the view. It's hard to deal with such people, since they don't see the down-sides to all the alternatives - they just don't want to see wind turbines (if they ever actually go outside or get into the back-country at all.). I hate NIMBYs. If you can't take a wider view and accept some change for the common good, then you ought not engage in activism. Wind-farms can be great for this country, and perhaps it would allow for the removal of more dams in Maine, and the restoration of more anadromous fish.

 

[mal4mac]

Nuclear will probably not dominate the energy mix in the US, at least not in the near term.

What are your arguments for this?

There is a place for renewable energy: wind, solar, geothermal. The challenge is to get the most out of each technology with minimal detrimental impact on the environment.

That *should* be the challenge, I agree.

 

[Astronuc]

What are your arguments for this?

Principally, economics and the lack of a viable back end strategy (reprocessing and/or direct disposal in a repository) in the near term (next 10-20 years). There are 104 operating nuclear reactors in the US, and there is 1 older unit to be finished, and two units for which construction is about to begin, another 2 units for which approval is sought, and several more in planning. Even if 100 new units were constructed, nuclear would only provide 40% of domestic electricity.

Economically, the price of natural gas is so low that utilities are more inclined to add natural gas generation if needed rather than coal, oil or nuclear. Coal supplies about 50% of electricity in the US, non-coal fossil about 21% (~18% natural gas, ~3% oil), hydro ~ 6-7%, and nuclear ~20%. The retiring CEO of Exelon, John Rowe indicated he wouldn't commit Exelon to any new nuclear builds until the costs, including back end, were well defined. Most nuclear utilities use nuclear as baseload, and most units produce 0.9 GWe or more.

References (primarily electrical generation):
http://www.epa.gov/cleanenergy/energy-and-you/index.html
http://grist.org/climate-energy/2011-04-22-chart-of-the-day-the-u-s-energy-mix-in-2035/
http://www.nrel.gov/docs/fy08osti/41869.pdf

Short term energy outlook - http://205.254.135.24/forecasts/steo/report/ - includes liquid fuels used in manufacture and transportation, residential heating, as well as electrical generation.

In the longer term, nuclear fuel resources are finite, and the thermodynamic efficiency of conventional plants rather comparatively low - ~32-37%. Combined cycle gas plants can have thermodynamic efficiencies approaching 60%. Of course, fossil fuels are also finite. I'd like to see more efficient plants. In the long term, I think we need to leave a legacy of viable energy production for future generations - well beyond just a few centuries or a few millenia.

 

[evacek3]

What about thorium reactors?

 

[Astronuc]

What about thorium reactors?

There are certainly many proponents of nuclear plants based on the thorium cycle - both with conventional solid fuel form and liquid (fluoride salts) form. China and India both have research programs on Th-fuel cycle. Thorium is three times as abundant as uranium, so the resources would last longer.

Thorium requires a certain amount of fissile inventory to get started, then the approach is typically to produce (breed) U-233 from Th-232, much the same way Pu-239 is bred from U-238 (neutron capture followed by successive beta decays).

There have been some expriments with small liquid fuel reactors (MSR) at ORNL, and with conventional fuel in two LWRs (Indian Point 1 and Shippingport) in the US. The conventional programs were rather limited.

LWRs are still thermodynamically limited by the Rankine cycle, whether they are thorium or uranium based.

High temperature reactors using a Brayton cycle (and perhaps bottomed with a Rankine cycle) are possible, but materials degradation issues need to be addressed.