Nuclear energy: for or against?

[tg22542]

What are your thoughts on nuclear energy ? Are you for it or against?

In my opinion the only cons are that fact that they cost large amounts to build/maintain, as well as they develop radioactive waste. But the waste can be dealt with, thing plants can power entire cities while a regular power plant is only local energy. Should we build more nuclear plants or no? Give me your thoughts!

Thanks :)

 

[russ_watters]

I agree!

 

[ImATrackMan]

Aside from the obvious inherent danger (see: every nuclear disaster ever), and thw radioactive waste (that can be dealt with) nuclear energy is one of the safest*, and easily (used loosely) harnessed forms of energy. I mean, if the waste (spent fuel rods, condensed cooling water, etc.) is disposed of properly, then there's virtually no pollution. I'm perfectly fine living near (about 20 miles) from the Turkey Point Nuclear Power Station.

IOW, I'm all for it.

 

[tg22542]

Why should we switch from our regular sources to nuclear?

 

[russ_watters]

It is plentiful, domestic, clean and cheaper than alternatives with similar attributes.

 

[aquitaine]

Indeed. Besides, every other attempt to change away from it has been a dismal failure resulting in more fossil fuels being used

Germany’s dash for coal continues apace. Following on the opening of two new coal power stations in 2012, six more are due to open this year, with a combined capacity of 5800MW, enough to provide 7% of Germany’s electricity needs.

Including the plants coming on stream this year, there are 12 coal fired stations due to open by 2020. Along with the two opened last year in Neurath and Boxberg, they will be capable of supplying 19% of the country’s power.In addition, 27 gas fired stations are due on line, which should contribute a further 17% of Germany’s total electricity generation. (Based on 2011 statistics, total generation was 575 TwH).

 

[wukunlin]

imo risks of nuclear energy has been blown way out of proportion by the media and the so-called "environmentalists"

 

[BruceW]

it's not like we have a choice about building nuclear power stations, since fossil fuels are running out and 'renewable energy' is not nearly enough to supply our energy needs. The new nuclear power stations should be built right, so if something does go wrong, the power station 'melts down' (or whatever the term is) in a safe way, such that the surrounding area is not at risk.

I would really like to see nuclear fusion provide our energy, but there is not quite the technology yet. Fusion would not need uranium fuel (like fission does). Also, fusion would not create nuclear waste. Also, I would like to see other 'renewable sources' supply our energy, maybe this is possible in the distant future, if we keep funding renewable energy projects, so that the technology progresses to something that can actually provide all our energy.

 

[aquitaine]

Also, fusion would not create nuclear waste.

Yes it does, it just doesn't produce as much. Even so, the alleged nuclear waste problem is not technical (contrary to the Church of Gaia's claims) but rather it's a political problem.

 

[BruceW]

what's the waste? Helium? that's not really a problem right? we can just use it to make balloons and have a party :)

 

[aquitaine]

what's the waste? Helium? that's not really a problem right? we can just use it to make balloons and have a party :)

Since it's in a nuclear reaction I'm pretty sure it's going to be radioactive for a while.

 

[Astronuc]

Fusion reactions that produce neutrons will necessarily result in activated materials, e.g., in the first wall and related structures. If there is a Li blanket, then tritium will be produced, which is fuel, but nevertheless radioactive. When parts of the first wall are removed - they will have to be sent somewhere while the radionuclides decay, or otherwise diposed as radioactive waste.

Some concepts have a fission blanket, so that certainly would produce fission products, aka nuclear waste.

 

[lavinia]

To me we could use nuclear energy for a short time say 50 years then switch to some other source like fusion. It would be far cleaner than fossil fuels and it would provide vast amounts of energy. Its short life span would tend to avoid any long term risks.

 

[BruceW]

Fusion reactions that produce neutrons will necessarily result in activated materials, e.g., in the first wall and related structures.

ah, right. the magnetic field can't contain stray neutrons. I guess fusion is not so great as I thought. still pretty cool, I think.

 

[Astronuc]

ah, right. the magnetic field can't contain stray neutrons. I guess fusion is not so great as I thought. still pretty cool, I think.

There are some aneutronic reactions, e.g., d+³He or p+¹¹B, but they are difficult from a pressure/temperature standpoint, and ³He is exceedingly rare and only available from decay of ³H or certain spallation reactions. Making fuel from nuclear spallation reactions is not practical or economical.

 

[aquitaine]

ah, right. the magnetic field can't contain stray neutrons. I guess fusion is not so great as I thought. still pretty cool, I think.

It is, but not the reasons you first thought. Even though we have thousands of years of fissionables, we have even more fusionables. That's the real reason why the environmentalists opposed fission and will also try to scare people about fusion: Abundant, inexpensive energy.

 

[BruceW]

that's why they oppose fission and fusion?!? You mean that they are worried their funding will be given to nuclear power projects instead?

 

[gmax137]

that's why they oppose fission and fusion?!? You mean that they are worried their funding will be given to nuclear power projects instead?

There is a certain influential bunch whose dream world has 95% of the current population somehow disappearing, with the remainder living kind of like the Amish but with the Internet. Oh , and they are in charge and get to decide who survived and who gets shunned.

 

[BruceW]

who is this bunch? are you yanking my chain? :)

 

[gmax137]

Just google "environmentalist population". Start with Paul ehrlich. There's plenty more after him.

 

[jim hardy]

To me we could use nuclear energy for a short time say 50 years then switch to some other source like fusion. It would be far cleaner than fossil fuels and it would provide vast amounts of energy. Its short life span would tend to avoid any long term risks.

I worked thirty+ years in a plant and used to say at dinner conversations, when asked:

The Lord gave us fire which got us through the ice ages
and when machinery age began ~1700 we found the coal He'd thoughtfully left near the surface
which was a much better fuel for our steam boilers than the wood we'd grown up on.

When boilers got really good ~1900 we stumbled on the oil He'd thoughtfully left also near the surface
and we moved our fire from the boiler into the working cylinder. Hence the age of internal combustion.

Internal combustion was mighty good by 1940, and about that time we learned to split the uranium He'd also left near the surface . He left thorium for us as well, and between them we've enough fissile fuel in the crust of the Earth to keep present lifestyle perhaps another 500 years.
By that time somebody should have fusion figured out.

So - in my humble opinion,
we need to bite the bullet and do a proper job of waste management.

Else civilization will crumble as carbon fuel becomes scarce and increasingly unviable.


old jim

 

[Thermalne]

I'm for nuclear energy. Who wouldn't like carbon neutral energy!

 

[nikkkom]

it's not like we have a choice about building nuclear power stations, since fossil fuels are running out

Yes, but not soon. There is enough coal for about 300 years...

and 'renewable energy' is not nearly enough to supply our energy needs.

Plainly untrue. Solar alone is enough. Do the math.

The new nuclear power stations should be built right, so if something does go wrong, the power station 'melts down' (or whatever the term is) in a safe way, such that the surrounding area is not at risk.

The problem isn't so much technical, but organizational.
As a recent example, TEPCO management was willfully ignorant of tsunami danger.
So, the new stations will be declared safe... until we discover that management again lied to us (and to itself, probably) about something.
How do you propose to fix that?

 

[jim hardy]

Yes, but not soon. There is enough coal for about 300 years...
Plainly untrue. Solar alone is enough. Do the math.
The problem isn't so much technical, but organizational.

Ahh you nailed that one.
I watched bureaucracy at work for thirty five years.
C Northcote Parkinson's books on that subject should be required in all business and science curricula. Even Gorbachev quoted him, and in reading "Peristroika" his influence on the Russian leader is obvious.

As a recent example, TEPCO management was willfully ignorant of tsunami danger.
So, the new stations will be declared safe... until we discover that management again lied to us (and to itself, probably) about something.

That was (and still is) correctible.

We lie loudest when we lie to ourselves. Eric Hoffer

Management is doing things right; leadership is doing the right things. Peter Drucker

You will never understand bureaucracies until you understand that for bureaucrats procedure is everything and outcomes are nothing. Thomas Sowell

Long ago I became a fan of the three guys quoted above because of their insight into human behavior.
I didn't object when, after TMI, Carter scrubbed our breeder program. I honestly thought at the time we needed a generation for management science to catch up with technology. (I did often quip though, that anti-neutrinos from fission must somehow interact with human neurons to produce self defeating behavior. More at Barbara Tuchman's "March to Folly" )

How do you propose to fix that?

Twelve step programs work for individuals because they insist on honest behavior.
When one lives an honest life things just go better.
Same is true for organizations.
I watched a choking, dying bureaucracy turn around and become quite effective.
It was done by a top manager who came down into the ranks and insisted on old fashioned rigorous honesty from the bottom up. He fired a couple of middle managers for trying to 'pull the wool'.
A year after his arrival we were walking out to the parking lot one evening and he said to me "Plants are running a lot better now, aren't they Jim?" (We'd just set a performance record.)
Then he added "With the same working folks as before, eh? "

His point was obvious.

old jimps: thanks mentors for recent cleanup of thread.

 

[BruceW]

Plainly untrue. Solar alone is enough. Do the math.

you wouldn't be able to use electricity at night. There are ways around this, but they are not efficient. Also, is solar alone really enough? I mean with today's efficiency, and taking into account that we can only put solar cells on a tiny fraction of the Earth's surface. Most is water, or terrain that is hilly, rocky, covered by vegetation. And a lot of the 'nice' land is used by humans already for farming, housing, e.t.c.

 

[nikkkom]

you wouldn't be able to use electricity at night. There are ways around this, but they are not efficient.

It remains to be seen whether they can or can't be made efficient.

Also, is solar alone really enough? I mean with today's efficiency, and taking into account that we can only put solar cells on a tiny fraction of the Earth's surface.

Wrong. There are huge deserts.
For example, Sahara is not a tiny fraction of Earth surface. With today's efficiency, PV-covered Sahara would generate, averaged over 24 hours, 10 times more electricity than total world consumption.

As I said, do the math. (Start with the surface ares of desert-ish sparsely populated US states). I did. To my surprise, solar alone can generate all electricity US consumes today.

 

[gmax137]

... do the math ...

No, do the engineering.

 

[BruceW]

Wrong. There are huge deserts.
For example, Sahara is not a tiny fraction of Earth surface. With today's efficiency, PV-covered Sahara would generate, averaged over 24 hours, 10 times more electricity than total world consumption.

As I said, do the math. (Start with the surface ares of desert-ish sparsely populated US states). I did. To my surprise, solar alone can generate all electricity US consumes today.

This is fine for supplying cities near deserts, but for cities far away, the energy lost via transmission would be huge. Getting back to the main point, OK maybe it is technically possible to generate all our power by solar within the next 300 years (even just using current technology). So I guess what I'm really saying is that it's not possible to do this without drastically changing our lives.

 

[jim hardy]

Do the math then the engineering...

Here's a map of available solar energy per day for every month, let's pick March because it includes the equinox, January is leaner and July is richer.
http://rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/atlas/serve.cgi
EDIT: map removed it was too wide for screen, it's at http://rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/atlas/colorgifs/3.GIF

Looks like the sun delivers a daily average of perhaps 3 kwh per square meter per day .
At collection efficiency of , let's be generous and assume 15%, yields 0.45kwh per square meter per day.
Only Nasa can afford those 40% efficient cells for they cost 100X what a commercial 8% one does.

Now the US electrical consumption in 2011 was 3.75 X 10^12 kwh
http://www.ipsr.ku.edu/ksdata/ksah/energy/18ener7.pdf

which divided by 365 yields 1.02 X 10^9 kwh per day, requiring 2.27 X10^10 square meters of collector.

The US has area of 9.16 X 10^ 12 square meters of land area
http://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area
and \frac{2.27E10}{9.16E12} = .0025
so covering ~1/4% of the whole country with solar panels could make as much electricity as we used in 2011.

That's a lot of solar panels. And to make transmission practical they'd have to surround the cities as do today's steam plants. I suspect their immense size would wreak political havoc with suburbia..

Also they'd only make electricity when sun is well above horizon.

solar insolation graph courtesy http://www.physibel.be/voltra_sol1.htm

I think it'd a better idea to use solar to boost the daytime efficiency of fossil or nuclear steam plants as described in this article:
http://www.nrel.gov/csp/troughnet/pdfs/bruce_kelly_isccs.pdf

for that way we could still watch TV , read Physics Forums and run the dishwasher after dinner.

Thoughts ? Corrections ?

 

[nikkkom]

That's a lot of solar panels.

PV costs: "For large-scale installations, prices below $1.00/watt were achieved. A module price of 0.60 Euro/watt ($0.78/watt) was published for a large scale 5-year deal in April 2012."

Correct me if I'm wrong, but construction of a gagawatt nuclear plant costs far more than $1B.

And to make transmission practical they'd have to surround the cities as do today's steam plants.

No, they don't have to surround cities. A HDVC transmission line can transmit gigawatts of electricity over a link of more than one thousand miles.

 

[jim hardy]

PV costs: "For large-scale installations, prices below $1.00/watt were achieved. A module price of 0.60 Euro/watt ($0.78/watt) was published for a large scale 5-year deal in April 2012."

Correct me if I'm wrong, but construction of a gagawatt nuclear plant costs far more than $1B.

I don't think you're wrong. In late 60's I saw one built for $120 million.
By late 70's that had escalated to ~ 1 billion. Our CEO said of the regulatory environment: "I can't gamble the entire net worth of the company on a plant I may not even be able to run." He went back to coal.

Last I heard the figure was in the $5B range.

No, they don't have to surround cities. A HDVC transmission line can transmit gigawatts of electricity over a link of more than one thousand miles.

Ahhhh but I did say practical...
Let's take that for a thought experiment.
Pick a 150 km square in Arizona and cover it with solar cells. In fact make it 200 km square so there's room between panels for lighting and ventilation of the work area underneath them.
And build those transmission lines to NYC, Miami, LA and Seattle.
From around 8AM to 6PM Mountain time there'll be solar electricity available.
So the steam plants can cut back but must remain warm and spinning at perhaps 20% power, ready to pick up load as the sun goes down in Arizona. What have we saved? A lot of coal, but we haven't displaced existing infrastructure we've doubled it.

OM and I bounced around some similar ideas in another thread. My personal leaning is away from centralization toward local economizing , to achieve the same savings of coal. It'd make people feel involved and empowered if they were to maintain their own rooftop collectors.

 

[atyy]

He left thorium for us as well, and between them we've enough fissile fuel in the crust of the Earth to keep present lifestyle perhaps another 500 years.
By that time somebody should have fusion figured out.

Maybe they'll have quantum computers too!

 

[jim hardy]

Maybe they'll have quantum computers too!

they'll doubtless use base e arithmetic.

 

[russ_watters]

PV costs: "For large-scale installations, prices below $1.00/watt were achieved. A module price of 0.60 Euro/watt ($0.78/watt) was published for a large scale 5-year deal in April 2012."

Correct me if I'm wrong, but construction of a gagawatt nuclear plant costs far more than $1B.

Where did you get that, the wiki? It also says this:

The less solar power costs, the more favorably it compares to conventional power, and the more attractive it becomes to utilities and energy users around the globe. Utility-scale solar power can now be delivered in California at prices well below $100/MWh ($0.10/kWh) less than most other peak generators, even those running on low-cost natural gas.

In other words, at peak times when electricity is at its most expensive, solar power is starting to become competitive. That's nice, but that does not equate to replacing the base load power, only the peaking power.

In any case, the error you made is that that's just the cost of the cells themselves, not the cost of the plant, nor have you properly compared it to the cost of a nuclear plant, which runs 24/7. After you've calculated the installed cost per watt, you need to multiply the cost by 6 to equal the energy generation of a nuclear plant. Ie, 1 watt of nuclear power gives you about 8000 watt-hours of electricity per year. 1 watt of solar power gives you about 1400.

In real-life, solar plants have not fared well economically, except in cases where the peak cost of electricity is very high or the infrastructure cost of running wires is so high it makes sense to just use solar not not run wires. But oops - you want to run transmission cables thousands of miles, so that benefit actually becomes a liability.

 

[Chronos]

It's unfortunate we have not heard more about the latest generation of nuclear reactors - pebble bed reactors. They are immune to nightmarish melt down scenarios, inexpensive to build and scalable. They can be safely located near heavy demand areas, occupy little real estate, and are highly efficient.

 

[nikkkom]

I am not seriously proposing that US should be completely switched to solar power. I think we need to use a mix of generation technologies, _including nuclear_.

I responded to argument that "renewables aren't competitive", which is not true.

 

[jim hardy]

I think we need to use a mix of generation technologies, _including nuclear_.

I completely agree.

 

[atyy]

It's unfortunate we have not heard more about the latest generation of nuclear reactors - pebble bed reactors. They are immune to nightmarish melt down scenarios, inexpensive to build and scalable. They can be safely located near heavy demand areas, occupy little real estate, and are highly efficient.

How close to a heavy demand area can it be located? Could it be put in a residential area? Has anyone built one yet?

 

[russ_watters]

How close to a heavy demand area can it be located? Could it be put in a residential area?

I don't see how those are relevant questions: nuclear power plants are already located in residential areas and near major cities. I live near Limerick (Pa) station, which is in a well populated suburb of Philly.

 

[mheslep]

PV costs: "For large-scale installations, prices below $1.00/watt were achieved. A module price of 0.60 Euro/watt ($0.78/watt) was published for a large scale 5-year deal in April 2012."

The *installed* cost of solar power has been slower to drop and resides several times higher than $1/Watt. That is, the price of the panels themselves could go to zero and after installation solar would still be marginally competitive with the cheapest traditional sources.

And the above still does not include the cost of any backup system to include the cost of keeping some gas fired electric plant ready but idle while solar power is performing.

 

[nikkkom]

It's unfortunate we have not heard more about the latest generation of nuclear reactors - pebble bed reactors. They are immune to nightmarish melt down scenarios

Pebble bed reactors are not immune to meltdowns.
To be significantly more resistant to meltdowns than current reactors, reactor needs to continually get rid of fission products (what LFTRs are planning to do).

inexpensive to build

Remains to be seen...

 

[atyy]

I don't see how those are relevant questions: nuclear power plants are already located in residential areas and near major cities. I live near Limerick (Pa) station, which is in a well populated suburb of Philly.

What then was Chronos referring to when he mentioned pebble bed reactors being sited near heavy demand areas as an advantage?

 

[russ_watters]

What then was Chronos referring to when he mentioned pebble bed reactors being sited near heavy demand areas as an advantage?

Dunno, could be a political issue.

 

[Thermalne]

Pebble bed reactors are not immune to meltdowns.
To be significantly more resistant to meltdowns than current reactors, reactor needs to continually get rid of fission products (what LFTRs are planning to do).



Remains to be seen...

The point is... there are many Gen4 or "innovative" designs that have pros and cons that would be useful to use for various reasons. We should build a mixture of reactors (except anything with a positive reactivity coefficient) that are more passively safe than current light water reactors (They are still really freaking safe). Also, there are plenty of ways to make light water reactors passively safe (and not dependent on offsite or onsite power to cool the reactor) and that's how futures ones should be built.

Also, Pebble Bed reactors are cool, but so are molten salt and liquid metal reactors and high temperature gas reactors too!

Also relevant: http://nuclearstreet.com/nuclear_po...e-technology-for-doe-funding-opportunity.aspx

 

[RobinSky]

This might be a retarded question, if so please forgive me I have no knowledge in nuclear physics.
But is it possible to use the nuclear waste as some kind of fuel? If not, is it impossible due to laws of physics or just mainly due to impractical reasons? For me as a novice, the radiation from the nuclear waste is radiating energy, and if it was possible to use that radiation as some kind of fuel, it would be a cool idea.

Thanks in advance.

 

[Thermalne]

This might be a retarded question, if so please forgive me I have no knowledge in nuclear physics.
But is it possible to use the nuclear waste as some kind of fuel? If not, is it impossible due to laws of physics or just mainly due to impractical reasons? For me as a novice, the radiation from the nuclear waste is radiating energy, and if it was possible to use that radiation as some kind of fuel, it would be a cool idea.

Thanks in advance.

Most nuclear "waste" (i.e. used fuel) has only had about 2-3% its potential energy used. Fuel recycling (France does this) and some reactor designs use or recycle previously used fuel.

See: http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Fuel-Recycling/Processing-of-Used-Nuclear-Fuel/#.UfWG9Y1kxJQ and http://www.nei.org/Key-Issues/Nuclear-Waste-Disposal/Recycling-Used-Nuclear-Fuel

Very good question. I'm glad you asked.

 

[RobinSky]

Most nuclear "waste" (i.e. used fuel) has only had about 2-3% its potential energy used. Fuel recycling (France does this) and some reactor designs use or recycle previously used fuel.

See: http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Fuel-Recycling/Processing-of-Used-Nuclear-Fuel/#.UfWG9Y1kxJQ and http://www.nei.org/Key-Issues/Nuclear-Waste-Disposal/Recycling-Used-Nuclear-Fuel

Very good question. I'm glad you asked.

Cool, thanks for the good links! I had no idea about this, and that so little energy is used of the fuel really suprised me. Is there any limit set by nature from the energy we can get from our nuclear fuel? Something like Bet'z law but for nuclear fuel.

/Robin

 

[BruceW]

I think that Iron is the lightest element that you could keep doing fission on to get energy (in a theoretical sense). For lighter elements, if you continue to do fission, you have to put in more energy than you get out. So in principle, you could do fission repeatedly on some nuclear fuel (and its daughter atoms), until you are left with Iron. But of course, there are reasons that we do not do this. I guess you could call them 'practicality reasons'. http://en.wikipedia.org/wiki/Fissile

 

[RobinSky]

But what limits us from not "extracting" more than just 2-3% of the energy? Is it limits set by nature or are the reasons because it's hard with current technology? This is very interesting!

 

[gmax137]

Many of the fission products are good neutron absorbers. With time the fission products build up and absorb more and more neutrons. So, there are fewer and fewer neutrons available to maintain the chain reaction.

You could take the fuel out of the core and process the material to remove the fission products and then re-use the uranium to make new fuel. This "re-processing" is not done here in the US.