Nuclear energy: for or against?

[etudiant]

It may be that the materials issues that must be dealt with to build a durable fusion reactor are so difficult that a different approach will be needed.
One such approach is to focus on fusion reactions whose energy is emitted primarily as charged particles, rather than as neutrons. That would greatly simplify the system, as the charged particles could generate electricity directly. The idea would be to brake them electrostatically, which also limits the material damage from particles plowing through the reactor structure.
Of course, such fusion reactions are much more difficult to achieve, requiring much higher plasma temperatures and confinement performance, so they have been back burner efforts thus far. However, serious money is beginning to go into the fusion reactor engineering and the problems are becoming manifest. It is possible that there may be a road map reassessment in the relatively near future, especially if there is further progress with the plasma confinement work.

 

[mheslep]

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.

On the subject of alternatives: a molten fuel reactor design would build the reprocessing into the loop, removing fission products on the fly which enables a very high theoretical burn-up, thus low waste, long periods between refueling and so on.

 

[mheslep]

...
It is a disaster, but on a much lesser scale than the USs housing bubble for example, which was perhaps 10 times bigger and wrecked many more lives.

How many lives were "wrecked" by the nuclear aspect of Fukushima versus those actually displaced and killed or grievously injured by the Tsunami?

 

[mheslep]

In Sahara, you hardly ever need a backup.

In addition to night time, in January and December mostly cloudy days are 10%, and 20-25% mostly cloudy (Cairo), at least.

 

[jadair1]

In addition to night time, in January and December mostly cloudy days are 10%, and 20-25% mostly cloudy (Cairo), at least.

I wonder if supercapacitor technology has advanced enough to store excess electricity during peak generation times to store enough energy for low generation times?

I guess that would be a question for the Electrical Engineering forum.

 

[etudiant]

I wonder if supercapacitor technology has advanced enough to store excess electricity during peak generation times to store enough energy for low generation times?

I guess that would be a question for the Electrical Engineering forum.

Not a chance.
Supercapacitors are still well short of the performance level needed to replace the auto battery.
Storing enough to run a city for hours or days is not in sight.
There may however be applications to level the output of wind turbines, which fluctuates even on a second to second time frame, to the discomfort of the overall electric grid.

 

[jadair1]

Not a chance.
Supercapacitors are still well short of the performance level needed to replace the auto battery.
Storing enough to run a city for hours or days is not in sight.
There may however be applications to level the output of wind turbines, which fluctuates even on a second to second time frame, to the discomfort of the overall electric grid.

Thanks, I wasn't aware of where the present technology was, my knowledge of this stuff is 10 - 15 years or so out of date.

An alternative could possible be liberating hydrogen and oxygen during peak producing times to run a generator at off times, although I think this would be very inneficient.

Now that I think about it you may be correct in that the supercapacitor application was to smooth the output of wind turbines.

Geothermal and tidal power generation may be the best bet for continuos and relatively stable power generation in areas where they are feasable.

I live on Vancouver Island and both these forms of generation are very feasable, not sure how economical they would be though.

 

[mfb]

An alternative could possible be liberating hydrogen and oxygen during peak producing times to run a generator at off times, although I think this would be very inneficient.

It is very efficient if you have cars that run with hydrogen. To use overproduction in that way, you need much more electrolysis capacity than you'll actually use (as it does not run 24/7 at its capacity limit).

How many lives were "wrecked" by the nuclear aspect of Fukushima versus those actually displaced and killed or grievously injured by the Tsunami?

I saw an upper limit of 200, compared to 20000 from the Tsunami.

The alternative coal is actually killing people. Even if that number is off by a factor of 10, that's way more than all nuclear accidents combined.

If these costs are factored into the price of the power I think Nuclear Power is to expensive to produce without massive government subsides and that doesn't even factor in the economic cost of a Chernoble or Fukushima type disaster!

If you divide the costs of Chernobyl and Fukushima by the amount of electricity generated by all power plants worldwide, you get a small number. And I am not sure if that is a fair way to include results from natural accidents.

Sure, nuclear power is not as cheap as the electricity market prices - but that's not a fair comparison. No source is as cheap as that.

Amazing depth of economical analysis.
Fusion plans don't need rare Earth metals, right?

Probably not as much as photovoltaics and wind energy, but that is just a guess.

 

[jadair1]

If you divide the costs of Chernobyl and Fukushima by the amount of electricity generated by all power plants worldwide, you get a small number. And I am not sure if that is a fair way to include results from natural accidents.

Sure, nuclear power is not as cheap as the electricity market prices - but that's not a fair comparison. No source is as cheap as that.


Probably not as much as photovoltaics and wind energy, but that is just a guess.

I do not believe the Fukashima disaster was entirely a result of a natural disaster, rather it was a failure of management, for gods sake upper management actualy talked about abondoning the plant.

In 2008, I believe it was, the engineers postulated an earthquake and tsunami very close to the one that hit. Nothing was done about it due to the cost!

Yes 20,000 some odd people lost there lives due to the natural disaster, this is horrible indeed but those of us that live in areas prone to these type of natural disasters are playing the odds that it will not happen in our lifetimes.

What I have a problem with Fukushima is that it is a man made disaster not a natural one.

And it has the potential to get much worse, if Tepco, those incompatent twits, lose control of SFP 4 and need to evacuate Daichi AND Daini Japan is toast!

By the way I live in BC and power generated by dams is some of the cheapest in the world.

I will ignore the 100's of thousands of square miles flooded for the resevoires behind them, I prefer fishing to hiking in a forest or farming valley bottoms.

Nothing is perfect, we just need to keep on working on energy systems that do the least damage, whatever they are!

 

[mfb]

I do not believe the Fukashima disaster was entirely a result of a natural disaster, rather it was a failure of management, for gods sake upper management actualy talked about abondoning the plant.

It was certainly not entirely due to a natural disaster, but it wouldn't have happened without that.

In 2008, I believe it was, the engineers postulated an earthquake and tsunami very close to the one that hit. Nothing was done about it due to the cost!

Yes 20,000 some odd people lost there lives due to the natural disaster, this is horrible indeed but those of us that live in areas prone to these type of natural disasters are playing the odds that it will not happen in our lifetimes.

There is always a trade-off between risk and costs. How expensive would it have been to lower the death toll of the tsunami? Which probability did the tsunami have?

By the way I live in BC and power generated by dams is some of the cheapest in the world.

Regions where this is viable on a large scale are rare.

I will ignore the 100's of thousands of square miles flooded for the resevoires behind them

In which way are they better than similar areas ruined for other reasons?

I prefer fishing to hiking in a forest or farming valley bottoms.

Some people (and other animals and plants and so on) prefer living there, see the massive environmental impact of the Three Gorges Dam for example.

Nothing is perfect, we just need to keep on working on energy systems that do the least damage, whatever they are!

Sure.

 

[etudiant]

Geothermal and tidal power generation may be the best bet for continuos and relatively stable power generation in areas where they are feasable.

I live on Vancouver Island and both these forms of generation are very feasable, not sure how economical they would be though.

Tidal power has been studied since at least the 1950s and France built a practical demonstrator at Rance, using a tidal basin with low speed turbines to tap the water flow energy. There has not been a larger unit built since afaik, so clearly the economics are hard to justify.

Geothermal is extensively used in Iceland, but has not had much success elsewhere, largely because managing the fluid flows is so hard.
Tapping deep reservoirs of very hot water is complicated by the associated dissolved minerals, that crud up the steam generators and are environmental headaches to dispose of.
Pumping clean water into deep areas of hot dry rock limits the mineral loads, but experience thus far is that the rocks fissure and the hot fluid gets lost, rather than returning to the surface to power a generator. Earthquakes are also a hazard from fluid injections, so there are few clear success stories here either.
There have been efforts to use the ocean heat differential between cold deep water and warm surface water to drive power plants, most recently by Lockheed Martin in Hawaii. No commercial business was born from these initiatives.

 

[jadair1]

Some people (and other animals and plants and so on) prefer living there, see the massive environmental impact of the Three Gorges Dam for example.
.

Not to mention if a massive landslide causes the dam to be breached and this is a very real possibility.

The same with the site 3 dam proposed for the Peace River in BC, in the Peace River region north of Hudson Hope.

The area is prone to massive sldes every 50 to 100 years, there is a standing joke in the area: Q: What is a mobile home? A: A house built on a hill!

I worked in the area for a few years and every year going up the hill to get out of the valley the Highways department was repairing a slide , not big ones mind you but still I think it is insanity to build a dam where there is such potential for disasterous consequences.

I am not against dams per say but to build them in places that disaster is almost garaunteed it is insanity.

 

[nikkkom]

How many lives were "wrecked" by the nuclear aspect of Fukushima versus those actually displaced and killed or grievously injured by the Tsunami?

Tsunami damage will be repaired, coastal defences beefed up, and life will continue.

Housing bust is even less destructive.

Whereas the area northwest of Fukushima, a "tongue" about 20 km long, several 100s of km^2, will be uninhabitable for 30-50 years. Most people who lived there will never return.

 

[etudiant]

Tsunami damage will be repaired, coastal defences beefed up, and life will continue.

Housing bust is even less destructive.

Whereas the area northwest of Fukushima, a "tongue" about 20 km long, several 100s of km^2, will be uninhabitable for 30-50 years. Most people who lived there will never return.

The housing bust ruined the lives of millions of Americans through foreclosures and evictions and the effects are ongoing with a derelict real estate market. The people hit by the effects are just as displaced and dispossessed as the Fukushima evacuees, forced from their homes by the consequences of failed government policies.

 

[QuantumPion]

There is a town in Pennsylvania that had to be evacuated and made off-limits (even had to demolish and re-route highways and railroad lines) due to an underground coal fire projected to burn for hundreds of years. There are similar incidents in other countries, particularly China.

 

[mheslep]

Tsunami damage will be repaired, coastal defences beefed up, and life will continue.

Housing bust is even less destructive.

Whereas the area northwest of Fukushima, a "tongue" about 20 km long, several 100s of km^2, will be uninhabitable for 30-50 years. Most people who lived there will never return.

Life will continue for the ~20,000 not actually killed or orphaned, and for those that avoided the obliteration of their homes, businesses, schools, hospitals, roads, agriculture, and utilities by the earthquake and tsunami. If concern for the future were applied objectively with regard only to prevention of likely harm, regardless of cause, then top priority must be a 20 meter sea wall along the Pacific coast of Japan or perhaps evacuation of population within five miles of the Pacific coastline. After those steps are taken, then one might consider how to avoid a radiation dose that could likewise be received by living on the Colorado Plateau for a year (up to 140 mrem/year)

 

[mheslep]

The housing bust ruined the lives of millions of Americans through foreclosures and evictions and the effects are ongoing with a derelict real estate market. The people hit by the effects are just as displaced and dispossessed as the Fukushima evacuees, forced from their homes by the consequences of failed government policies.

While tragic, how are any number of these foreclosures

http://www.csmonitor.com/var/archive/storage/images/media/images/102210-foreclosure-auction/8860858-1-eng-US/102210-foreclosure-auction_full_600.jpg


in any way comparable with this?http://ksj.mit.edu/sites/default/files/images/tracker/2011/TsunamiJapanAftermath.jpg

 

[nikkkom]

Life will continue for the ~20,000 not actually killed or orphaned, and for those that avoided the obliteration of their homes, businesses, schools, hospitals, roads, agriculture, and utilities by the earthquake and tsunami.

First, earthquake per se did not destroy much (a testament to Japanese building codes and quality).

Second, tsunamis aren't designs of men - reactors *are*, therefore, those men should be held accountable for their designs.

Third. As I already said, and you failed to see the distinction, tsunami-devastated area *will be rebuilt* and will return to normal life relatively quickly (~5 years), whereas contaminated areas will be economically dead for 10 times longer period.

 

[mheslep]

...Second, tsunamis aren't designs of men - reactors *are*, therefore, those men should be held accountable for their designs.

I understand that's a distinction you draw, but stating 'therefore' does not make an otherwise arbitrary assertion into an argument.

Though the tsunami was unavoidable, the damage from the tsunami arguably was not: 20-30m sea walls, elevated structures, or even coastal exclusion zones were possible preventative measures. Though with great cost, these could have drastically reduced and perhaps even eliminated the damage from the tsunami. The Japanese chose not to do so, as have most other peoples living on coasts throughout the world.

No human design is guaranteed perfectly safe, not in this world. Liability is commonly assigned where a design falls short of what was promised due to either negligence or fraud. Liability is not assigned simply because of a truism, i.e. it was designed by people. To do so would be an exercise in misanthropy.

Third. As I already said, and you failed to see the distinction, tsunami-devastated area *will be rebuilt* and will return to normal life relatively quickly (~5 years), whereas contaminated areas will be economically dead for 10 times longer period.

Nobody knows exactly what *will* be done. We can only know the past. Hiroshima was rebuilt, so was Nagasaki, largely within five years.

As for the contaminated areas, the exclusion zone has already been relaxed a bit two years after the incident. Predictions five decades out seem dubious, at least.

At midnight on 1 April [2012] the restrictions on several areas within 20 kilometres of the Fukushima Daiichi nuclear power plant were revised. A significant part of these had shown dose rates caused by ambient radioactivity to be below 20 millisieverts per year - the government's benchmark for the return.
Evacuated residents of Kawauchi village and Tamura City previously needed a police permit to visit the homes they were forced to abandon last year during the Fukushima nuclear accident. Now, they may return to homes and businesses without the use of protective equipment.

Note that several parts of the world have background radiation levels around 150 millisieverts per year.

 

[the_wolfman]

Second, tsunamis aren't designs of men - reactors *are*, therefore, those men should be held accountable for their designs.

Yes, as an engineer I agree that we are accountable for our designs. But there are real philosophical questions when it comes to designing for natural disaster. In particular how safe is safe enough.

On this question, there are many different schools of thought. Here are mine. First, you have to be prepared for any and all natural disasters that has a reasonable likelihood of occurring. Second, for the rare or unpredictable disaster, the consequences of a design failing should be small compared consequences of the disaster that caused the design to fail.

In the case of Fukushima, its arguable that a Tsunami of the magnitude had a reasonable likelihood of striking Japan. By this measure the power plant failed. But in truth, all of Japan failed on this part. This wasn't a failure one nuclear company, this was a failure of the entire society.

However, by the second measure, I believe the Fukushima did not fail. In total 16,000 people died due to the disaster, but not one person died from exposure to radiation. Furthermore if you look at the exposers that the workers received, only a few received a significant enough does to raise the chances of getting cancer. And even then, its not a guarantee that they will get cancer, nor that they will die from it if they do get sick. The general public received even smaller doses than that. In all the total health effect from exposer to radiation is going to be a lot smaller that 16,000 deaths.

 

[russ_watters]

First, earthquake per se did not destroy much (a testament to Japanese building codes and quality).

Second, tsunamis aren't designs of men - reactors *are*, therefore, those men should be held accountable for their designs.

You are trying to draw distinctions here that don't exist. This isn't Chernobyl where there was no natural disaster: every bit of what happened along the coast that day was due to the natural disaster. Fukushima's deficiencies were in protection from natural disaster.

In all 3 cases, engineering can mitigate the effects:
1. As you pointed out, there is good earthquake resistance in the construction of buildings.
2. Fukushima was not well protected from tsunamis.
3. The Japanese coast was not well protected from tsunamis.

The only real difference is the upfront cost of the protection due to the fact that Fukushima was intended to be protected and the coastline wasnt, but weighed against the cleanup costs both 2 and 3 would suggest engineering solutions. See: New Orleans for a similar example.

New Orleans also provides an example of displacement: 8 years later, the population is about 90,000 below what it was before Katrina. Given that engineering was supposed to protect New Orleans and didn't, it is a very similar situation to Fukushima...but worse of course, since 1800 people died.

We don't just throw up our hands and let nature have its way with us.

 

[etudiant]

While tragic, how are any number of these foreclosures

http://www.csmonitor.com/var/archive/storage/images/media/images/102210-foreclosure-auction/8860858-1-eng-US/102210-foreclosure-auction_full_600.jpg


in any way comparable with this?


http://ksj.mit.edu/sites/default/files/images/tracker/2011/TsunamiJapanAftermath.jpg
[PLAIN]http://upload.wikimedia.org/wikipedia/commons/thumb/7/74/Signpost_of_prayer_and_wish.JPG/640px-Signpost_of_prayer_and_wish.JPG[/QUOTE]

I do not think the reality of the situation is accurately portrayed by this juxtaposition.
A shot of blighted areas of Baltimore or Phoenix or any of the cities where a tidal wave of foreclosures has left masses of abandoned/boarded up buildings and ruined lives would be more representative.
The crisis has affected many more people and much larger areas in the US, plus as a man made disaster, it is much more socially damaging.

 

[QuantumPion]

Google some pictures of Detroit and you'd be hard pressed to tell the difference from Pripyat, Ukraine.

 

[russ_watters]

[Continuing previous thought]
Why does this matter? Similar to wolfman's post, I see a double standard. More people were killed and more damage was done by the tsunami, but while ALL nuclear plants have been shut down in Japan - even ones without tsunami risk - no one is talking about abandoning Japan's coastlines. The nuclear plant problems are seen as intractable and fatal, while the reality is that it is the vulnerability of the coast that is the intractable problem. Preventing future Fukushimas is relatively easy.

 

[LabratSR]

First, earthquake per se did not destroy much (a testament to Japanese building codes and quality).

The jury is still out on Unit 1.

2 Escalation of the accident

"4. Several TEPCO vendor workers who were working on the fourth floor of the nuclear reactor building at Unit 1 at the time of the earthquake witnessed a water leak on the same floor, which houses two large tanks for the isolation condenser (IC) and the piping for IC. The Commission believes that this was not due to water sloshing out of the spent fuel pool on the fifth floor. However, since we cannot go inside the facility and perform an on-site inspection, the source of the water remains unconfirmed.

5. The isolation condensers (A and B systems) of Unit 1 were automatically activated at 14:52, but the operator of Unit 1 manually stopped both IC systems 11 minutes later. TEPCO has consistently maintained that the explanation for the manual suspension was that “it was judged that the per-hour reactor coolant temperature excursion rate could not be kept within 55 degrees (Celsius), which is the benchmark provided by the operational manual.” The government-led investigation report, as well as the government’s report to IAEA, states the same reason. However, according to several workers involved in the manual suspension of IC who responded to our investigation, they stopped IC to check whether coolant was leaking from IC and other pipes because the reactor pressure was falling rapidly. While the operator’s explanations are reasonable and appropriate, TEPCO’s explanation is irrational."http://warp.da.ndl.go.jp/info:ndljp.../blog/reports/es-1/#toc-4spread-of-the-damagehttp://warp.da.ndl.go.jp/info:ndljp/pid/3856371/naiic.go.jp/en/report/

 

[LabratSR]

More on the earthquake risk.

http://warp.da.ndl.go.jp/info:ndljp...nt/uploads/2012/08/NAIIC_Eng_Chapter1_web.pdf

 

[gmax137]

... TEPCO’s explanation is irrational...

over cooling (exceeding allowable cooldown rate) is a well known concern that the operators would be very conscious of. Not "irrational" at all. It may be a fabrication, but it isn't an irrational one.

 

[a.ua.]

However, the Japanese regulator concluded.
Water splashes from the pool of fuel.
Condenser intact.
Is not it?
====================
That's interesting.
area that (what size km 2) will be occupied by solar panels, to be compared with AC power reactors in Fukushima 1.
Given the breadth, day and night, clouds.
Every hour of 2.5 gigawatts, 13 consecutive months

 

[LabratSR]

over cooling (exceeding allowable cooldown rate) is a well known concern that the operators would be very conscious of. Not "irrational" at all. It may be a fabrication, but it isn't an irrational one.

I agree and I'm a little curious if the translation got it right.

 

[mfb]

Nobody knows exactly what *will* be done. We can only know the past. Hiroshima was rebuilt, so was Nagasaki, largely within five years.

Well, nuclear weapons have a different isotopic composition and distribution scheme.

The area around the power plant where radiation levels will be problematic in a few years is very small. Smaller than typical areas ruined by mining brown coal, for example.

2.5 GW in full vertical sunlight needs an area of roughly 10km^2, with a realistic solar flux and averaged over a year this is more like 50-100km^2. And then you still need to store the energy somehow, as the sun rarely shines at night.

 

[russ_watters]

People cited the Three Gorges Dam, but I'm not sure the relevant fact was ever stated: It displaced 1.3 million people. The equivalent nuclear disaster would be something like Limerick Nuclear Plant in southeastern Pennsylvania (where I live) going Chernobyl and making Philadelphia uninhabitable.

 

[mheslep]

Well, nuclear weapons have a different isotopic composition and distribution scheme.

Sure, but unlike leaks from a shutdown reactor, weapons have a colossal neutron flux (still ~10e12 N/cm^2 at one mile for a 15 kt weapon, pg 13) that make things in line of sight of the detonation a candidate for activation and thus a further source of radiation.

 

[mheslep]

2.5 GW in full vertical sunlight needs an area of roughly 10km^2, with a realistic solar flux and averaged over a year this is more like 50-100km^2. And then you still need to store the energy somehow, as the sun rarely shines at night.

Agreed, if that was for collection by ~20% efficient photovoltaic panels. Interestingly, that area, ~50+ km^2, is just the amount of the of land drown by the man made lake built solely for cooling the reactor in Virginia closest to me.

 

[mheslep]

Tidal power has been studied since at least the 1950s and France built a practical demonstrator at Rance, using a tidal basin with low speed turbines to tap the water flow energy. There has not been a larger unit built since afaik, so clearly the economics are hard to justify. ...

One reason being that tidal is also an intermittent, though predictable, power source. The cost of storage and/or other backup still has to be eventually added, like the other intermittent sources.

 

[mheslep]

Do the math then the engineering...

Here's a map of available solar energy per day for every month, let's pick March...

...

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

... 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.

... I suspect their immense size would wreak political havoc with suburbia..

Thoughts ? Corrections ?

Nice. I get roughly the same, with a couple of comments.

I find it quicker to express demand in units of average power (428 GWe, 2011). I think the most useful solar flux maps are flat plat tilted at latitude (http://rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/atlas/colorpdfs/208.PDF), showing the annual average solar flux ranges from four hours of 1 kW power a day up to six or seven such hours in the southwest. That's a useful way to think about the subject since the actual solar flux hitting the ground does actually peak out at ~1kW - something to keep in mind if the collection method is pure thermal like solar hot water instead of photovoltaic, or the efficiency of PV jumps.

So then your figure with three hours is ~22 thousand sq km to produce the same average annual power demand, or about 150 km on a side. That sounds like a lot of land until it is compared to some other, current uses. I think you'll find existing rooftop areas, homes and warehouses, will about cover it. The single US military base out in White Sands, NM has an area of a similar order of magnitude. So too the existing highway system.

Serious problems do appear with the seasonal variation, as you mention. In January, http://rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/atlas/colorpdfs/209.PDF in the northern third of the country. This has a couple implications. If the annual fraction of daily power produced by solar is to stay constant through January, then the amount of installed solar has to be doubled or quintupled, at least, and the same goes for the daily storage.

Germany's big solar push reflects these facts and shows that, at those latitudes, the difference between winter and summer collection can be 20 or 25 to 1. That kind of over installation and storage is a non-starter. This means we're in effect required to *keep* a good part of the existing power system sitting on standby for the winter. That is, keep a big part of the existing power system that supplies 428 GWe from coal, gas, nuclear and hydro sitting around to run 3-6 six weeks a year: an expensive proposition.