Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror
×

Comment Re:Public cynicism about fusion (Score 1) 147

There are well-respected scientists still working on LENR/LANR reactions a.k.a. Cold Fusion. Peter_L._Hagelstein is one of them. He teaches a LANR class at MIT. His initial interest in the field was to debunk the claims, the evidence he saw convinced him otherwise. For the past years he has been systematically performing the experiments that determine the conditions for when it works and when it does not work. I.e., he appears to be an entirely legitimate scientists investigating a phenomenon that is not well understood but could have tremendous impact; this is the quintessential science.

ECat may well be fraudulent. Many characteristics of known frauds exist. If you examine the work of Hagelstein and others, you will not see similar evidence of fraud. You will see the work you would associate with scientists doing what they do best, examining the data, proposing theories, testing theories, sharing ideas and data.

The initial experiements that "debunked" cold fusion did not actually do so. In the case of the Princeton debunking, the actual data showed some over-unity behavior that was edited out before releasing the results. These experience were performed in a "race" to replicate and/or debunk because the claims were so exceptional. One could argue that those interested in debunking the claims were motivated by external factors. But others that disputed the claims have no evidence that they were externally motivated to do so.

I am not saying that they will ever be successful in making something commercially viable (though many are convinced this will happen). I am hopeful that this can happen as this would certainly be cheaper and cleaner than hot fusion much less fission. The actual environmental impact would be less than renewable energy technologies as well.

Comment Re: Fusion Confusion (Score 5, Interesting) 305

Well, since the whole purpose of fusion reactors is to make commercially useful power, it is pretty clear that we do not have a working fusion reactor by any reasonable definition.

Despite having spent billions (22 Billion USD on hot fusion research by US alone) on the problem so far, with billions yet to come, we do not have working fusion reactors. Even ITER will just be a prototype with no power generation at all. Cost to develop commercially, unknown but bound to be a lot of money.

The US alone has also spent around 15 Billion developing Fast Breeder reactors, and has little to show for it. Other countries have similar experience.

Estimated cost to develop commercial LFTR reactors seems to be in the range 3 - 20 Billion USD. A commercial LFTR prototype seems to be likely 1 billion USD by most observers.

And you still have to build the reactors -- that won't be cheap either. Every known possible solution to replacing our energy infrastructure has a large economic cost, and significant to large environmental cost as well. Kind of the way large-scale engineering works.

Yet the cost of doing nothing will be larger yet, at least eventually. Peak fossil fuel is coming sooner or later, even if you master shale and methane hydrates with high recovery rates and limited environmental impact. There are a lot of third-world people in this world that would gladly join the first-world lifestyle which puts a severe constraint on expanding fossil fuels usage to match the growth in demand.

Personally, the combination of LFTR and renewable sources seems most likely to me to be commercially successful by 2050. Why, because the needed development seem to be within or nearly withing the capabilities of current engineering in both cases. Engineers are very happy to deliver good enough when the perfect seems unattainable.

Comment Re:KSP (Score 1) 201

You have to be more even more patient than they are for a probe. To accelerate from low earth orbit to escape velocity the 1e-7 m/s^2 will take 1080 years. Enough for orbit maintenance, probably. Enough for probes, no not really -- No one plans for missions spanning thousands of years.

Comment Re:KSP (Score 2) 201

No, the question is how fast can it accelerate the average potato. NASA reported 30-50 mN of thrust., call it 40. The average potato is about 375 grams, call is 400 even so math is real east. F=m*a or a = F / M or 1e-7 m/sec^2. So, accelerate for 1 year and you reach the break-neck speed of 31.5 meters per second or 70.5 mph

It is going to take a long time to get that potato to Alpha Centauri. Especially considering that you have to also accelerate the mass of the Q-drive unit itself and the energy source to supply the Q-drive.

Now if the effect is real and the efficiency and can be improved you still have something potentially useful in-deed for satellites. You could even maneuver asteroids if you had lots of patience.

Comment Re:Time to start building more nuke plants as long (Score 3, Insightful) 288

TMI safety both failed and succeeded depending upon how you look at things.

It failed to prevent a partial meltdown of the reactor core.

It failed to prevent a significant release of radiation to the general environment as 15 curies (560 GBq) of iodine-131 (the most concering portion due to biological uptake to the thyroid)

It succeeded in terms of avoiding the wide-scale problems of Fukushima or Chernobyl

It failed in terms of public opinion of nuclear power being a reasonably source of energy production. Nuclear plant construction in US was virtually shut down after this, no new licenses till 2012.

 

Comment Re:... and that's not much. (Score 1) 190

Cs-237 is pretty hot, half life of about 30 yrs. How about

Pu-239 .435 kg
U-235 12500 kg
U-238 80,400 kg.

I am sure these sound scary to most people, though Cs-237 is presumably a significant component of the nuclear release in question.

Of course they sound much worse because you can make nukes out of these and that increases the radiation release rate by many orders of magnitude and that mushroom cloud, etc.

To Americans it's Cesium not Caesium, then again most American don't really know what that it is. And most don't understand radiation either.

Comment Re:I also measure distance (Score 2) 190

Conveniently, there is an even better comparison. You have to disperse all of the radioactive soil into the air to make a similar comparison. We don't actually pump soil into the air though. We do however burn coal.

Webpage According to the National Council on Radiation Protection and Measurements (NCRP), the average radioactivity per short ton of coal is 17,100 millicuries/4,000,000 tons, or 0.00427 millicuries/ton. This figure can be used to calculate the average expected radioactivity release from coal combustion.

Converting this to metric equates to about 0.174 MBq/ton (metric ton).

WebpageLargest coal plant in America burns 11 millions tons of coal per year.

Now 11,000,000 tons * 0.174 MBq / ton is 1.914e6 MBq -- a bit less than the twice the totally scary 1 trillion Bq

The average coal plant burns coal with around 0.5 trillion Bq / year

Now, not all of the radiation get released into the atmosphere, a lot of it ends up in the ash. But the ash is stored in ponds and left in piles on the ground, so its not a terrible improvement in terms of safe radioactive containment.

Comment Re:Good (Score 1) 342

I would settle for nice modular neighborhood-scale TFTR reactors for now. I don't expect to see Mr. Fusion in the years I have left. I don't expect Congress to contribute to either of these either. I might wish they get rid of some unneeded regulations, but I have little hope of this happening either.

Slashdot Top Deals

He has not acquired a fortune; the fortune has acquired him. -- Bion

Working...