On 4/15/2011 10:48, Orchid XP v8 wrote:
> Are you saying there's some sort of relationship between the halflife of a
> substance and how much radiation it emits?

Well, yeah. By definition, if the half life is a month, it emits half of all 
the radiation it'll ever emit in the first month. If the half life is a 
year, it takes a year to emit the same amount of radiation, so it's 1/12th 
as radioactive.

Indeed, that's exactly why you pile up a bunch of naturally-occurring 
uranium in a reactor. The atoms set each other off much faster than you'd 
get from normal unstimulated half-life decay.  Otherwise there wouldn't be 
any uranium left.

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

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On 4/15/2011 10:04, Orchid XP v8 wrote:
> So it's full of radiation, but if you smash it up, it somehow doesn't
> release any radiation? How would *that* work?

Why do I have to google for you?

http://en.wikipedia.org/wiki/Pebble_bed_reactor#Safety_features

> I *would* be surprised if you can make a car that can withstand a 100MPH
> crash. :-P

Yet again, reading comprehension is low. ;-) I didn't say anything about the 
*car* surviving the crash.

> And now we have to sit down and figure out who funded them to publish that,
> where they got their data from, what methods they actually used, etc. It's
> not as simple as "it's true, because this random website says so".

It's pretty commonly understood, and really not at all difficult to prove, 
considering you can go out and buy one of those cars and plug it in to see. 
It's hard to have controversial statements about things like "how much does 
gasoline cost?" or "how much electricity does this commercially-available 
consumer product use?"

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

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On 4/15/2011 10:05, Orchid XP v8 wrote:
> (Apparently current battery solutions aren't very efficient.)

Big power plants don't store power in batteries.

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

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On 14-4-2011 0:09, Patrick Elliott wrote:
> On 4/13/2011 7:26 AM, Invisible wrote:
>>>> I literally can't decide whether this is serious or not.
>>>
>>> I'm just gobsmacked.
>>
>> Ditto.
>>
>>> Be afraid be very, very afraid that there are people in the educated
>>> world that can ask those types of questions and those that will answer
>>> them.
>>
>> I honestly can't decide whether this is deadpan spoof or perfectly
>> serious.
>>
>> (Isn't there a law of the Internet about this effect?)
> Its called a Poe: "Without a winking smiley or other blatant display of
> humor, it is impossible to create a parody of Fundamentalism that
> SOMEONE won't mistake for the real thing."
>
> A corollary to this is one, I am not sure its been named, which states
> that no such parody you can make will ever be unique, since there is
> bound to already be some Fundamentalist, some place, making the same
> exact same argument/statement on an existing website.

Oh no, that means that someone really believes that because the society 
as a whole seems to have almost exactly the right amount of bakers, 
plumbers and housewives that must imply that the society is designed by 
a supreme being. And that the proof of that is that society is 
irreducible complex because if you remove one group, the bakers or the 
policeman, or the bus drivers, or...  the whole thing stops working, 
hence it cannot have been evolved.


-- 
Apparently you can afford your own dictator for less than 10 cents per 
citizen per day.

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On 4/15/2011 4:24 AM, Le_Forgeron wrote:
> Le 15/04/2011 11:21, Invisible a écrit :
>> This is the thing. I've heard a lot of environmental activists say "we
>> should stop doing X" or "we should stop doing Y". I haven't heard much
>> about "we should do Z instead".
>>
>> Burning fossil fuels is obviously stupid for a number of reasons. And
>> the alternative is...? What exactly?
>>
>> Nuclear power works in theory. In practise, if you make even the tiniest
>> mistake, just once, everything is ruined forever. (Or at least, for
>> several centuries.) And there's nothing you can do to fix it.
>>
>> Wind power is great. But... do you really want the whole country to go
>> black every time the wind stops blowing? Similarly, solar power. You
>> realise that the sun is below the horizon for hours at a time, right?
>> And some days, it's just not very sunny. For either of these things to
>> work, you seriously need high-efficiency power storage, so you can
>> collect power when it's there, and store it for when it's not.
>
> All these should raise a question: why would you need a perfect and
> continuous source of energy ?
> Because you were raised in such environment where performance is
> expected and requested all the time... time to change that way of thinking!
>
> It's like email: they are not an INSTANT delivery system.
>
> Back to middle-age, working from dawn to dusk but never past dusk.
> Working enough to survive the year, yet the year after is still unknown,
> not expecting interest-rate to provide wealth. Working about every day,
> in theory, but having great collective break to prepare and celebrate
> many holidays. one penny a day, 240 pences a year, such were the
> unqualified wages. It also means that there was about 60 days of work
> per season, not 90! (ratio of day off was not 1/7, rather 1/3. So you
> think that todays week-end is a progress... well 2/7<  1/3 !).
>
> Also, local production should be sufficient to sustain all. You might
> spent ten years without going further than 10 km from your home.
>
>
None of which worked worth shit, or as you imply. lol

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On 4/15/2011 5:26 AM, Bill Pragnell wrote:
> Invisible<voi### [at] devnull>  wrote:
>> Nuclear power works in theory. In practise, if you make even the tiniest
>> mistake, just once, everything is ruined forever. (Or at least, for
>> several centuries.) And there's nothing you can do to fix it.
>
> That's not really true. Chernobyl was caused by a very long chain of mistakes,
> all committed with a reactor design which was already itself a long chain of
> mistakes. It should be noted that most other countries have never built a
> reactor that could fail as catastrophically as this, even through wilful
> sabotage.
>
> TMI was also long chain of mistakes, which resulted in only the reactor being
> ruined, and they did fix it.
>
> I suppose you could say that Fukushima was really only one very big mistake,
> i.e. how big a tsunami was ever likely to be. However, they show every sign of
> being able to fix it eventually.
>
No, the "big" mistakes where:

1. Having no way to cool it, or certainty that the power systems would 
still work, to do so, if enough failures happened. And, no, battery 
backup doesn't work, if it lasts less than 24 hours.

2. Placing the old, spent, fuel in something that was ever *less* 
effectively cooled.

And, I would add 3. Presuming that a *big* reactor, which produces 
massive amounts of power, but where it would be nearly impossible to 
either make it less hazardous, or run battery backup long enough, or 
otherwise create a system that *could* compensate for major problems, 
remains bloody stupid.

In simpler terms, a small reactor wouldn't need to use as many, as hot, 
as poor emergency systems, etc., to do the same job, for a single city. 
Its having 4-5 reactors of that size, operating the power for dozens of 
cities, nearly all operating by narrow margins, which is the problem. 
And, even when they did improve things, it was to improve how waste 
energy/heat got recycled, to reduce the inefficiency of the system 
(something that could reduce our need in the US for plants by half, or 
more, if we did it, but we won't, because it costs to much to redo 
thousands of *old* plants, that where never built to do that, never mind 
those operating on 80 different sorts of fuel/energy sources.

The US systems are inefficient, and "smart power" won't change that, 
without altering the things "running" off the power, and the plants 
themselves. And, both of those cost more than just making smarter 
switches, and some smarter meters. But, more to the point, the theory is 
always, "Find a way to make lots, then send it some place else." This is 
damn stupid. It means more danger at the source, larger fuel use at the 
source, bigger disasters *when* they happen, fewer, and less effective, 
means to handle them, when they happen, and then you *waste* half of it 
in the first 3 miles, while running it 500 miles to the town that needs it.

Imagine if the Fukushima reactors had each been even 50% the size, with 
say 25% of the fuel rods, and better access. Cooling could have been fed 
in easier, a means to get into/fix things would have been simpler, etc. 
And, that isn't even speaking to options that might have existed, to 
simply kill the reactions *given the right design*, or lower it to the 
point where even with nothing working, it wasn't as big a risk.

We need "local" power. Shipping it on from external points, and hoping 
it all works, and is safe, was a great idea when you didn't care if you 
lost most of it, and all you needed to run was a few thousand light 
bulbs. Now.. its a waste of resources, and anything that can supply it 
is dangerous, and not just do to size, but do to the level of constant 
operation needed to just keep things working, including the plants 
themselves.

So, that would be my answer. Stop wasting resources on distant power 
systems, and build more local, smaller, less dangerous ones. Ones you 
don't care if you faze out, if other improvements crop up, like better 
solar. Otherwise... There are ways to reduce the need for distant/local 
sources, even with what is available, that, if not perfect, still 
reduces, for the short term, how much crap is used instead. But, those 
things are not going to be driven by corporations, they won't be driven 
by people in the pocket of them, and they won't be driven by buyers, 
unless the buyers get their heads out of their asses and stop doing 
things like whining about how they don't like 1st/2nd gen fluorescent 
bulbs, so they *must* have their old ones, and similar short sighted idiocy.

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On 4/15/2011 8:49 AM, Invisible wrote:
> On 15/04/2011 16:35, Darren New wrote:
>> On 4/15/2011 5:57, Invisible wrote:
>>> That's kind of my point. You only need to be slightly wrong about one
>>> tiny thing, and it's game over.
>>
>> Not really. Look up thorium salt reactors. They don't go critical, the
>> wastes are not very radioactive, you can't blow them up, etc etc.
>> They're much safer.
>
> As I understand it, normal nuclear reactors are incapable of a *nuclear*
> explosion. That doesn't mean that the cooling system can't overload and
> explode. Or freak weather conditions level the building. Or somebody
> flies a passenger jet into it. Or...
>
The problem isn't nuclear explosions, its hydrogen generated by the 
system, which get hot enough to ignite. Mind.. I am seriously unclear 
why they couldn't make like a permeable something that could grab up the 
hydrogen, react it again, and just generate water from the excess, as 
part of the cooling, but.. I am sure it just silly to imagine a way to 
get rid of the damn stuff in a useful way, instead of just letting it 
get generated in insane amounts, when the fuel housings start to corrode...

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On 4/15/2011 8:52 AM, Invisible wrote:
> On 15/04/2011 16:28, Darren New wrote:
>> On 4/15/2011 2:21, Invisible wrote:
>>> Nuclear power works in theory. In practise, if you make even the tiniest
>>> mistake, just once, everything is ruined forever.
>>
>> It's possible (in theory) to build a plant where such isn't the case.
>> It's just that afaik nobody is doing that, because nobody has already
>> done it.
>
> I'd be rather surprised if you can build a system powered by radiation
> such that it doesn't use much radiation.
>
There is a battery for small devices in the works that "does" that. The 
problem, in most cases, is that its not the radiation that is used, its 
the heat. That is why the reactors are made the way they are. They have 
to heat water, and the water runs turbines. Find a material that can 
readily transfer electrons, and restore itself, at a decent rate, such 
that you only need something "hot" enough to generate the current you 
need, and you would be way better off.

The closest to a "safe" reactor I think anyone is amounts to two pieces 
of radioactive material in opposite ends of a tube, where you have to 
"heat" one of them, to initiate the reaction, and the reaction them 
generates enough heat during decay to run a small scale turbine. The 
output being higher than needed to maintain the reaction. So.. Cut the 
power, and the reaction slows, and you no longer get "any" output (or 
nothing higher than it would produce without the input energy). But, I 
haven't read anything on that design for some time. And, at that time, 
they had only managed to detect radiation of the type generated during 
such a reaction, so I have no idea if they got the design to actually 
work at all or not (it was very preliminary).

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On 4/15/2011 10:05 AM, Orchid XP v8 wrote:
> On 15/04/2011 05:01 PM, Jim Henderson wrote:
>> On Fri, 15 Apr 2011 10:21:37 +0100, Invisible wrote:
>>
>>> Wind power is great. But... do you really want the whole country to go
>>> black every time the wind stops blowing? Similarly, solar power. You
>>> realise that the sun is below the horizon for hours at a time, right?
>>> And some days, it's just not very sunny. For either of these things to
>>> work, you seriously need high-efficiency power storage, so you can
>>> collect power when it's there, and store it for when it's not.
>>
>> And most solar collection and all wind powered systems I've seen actually
>> include that storage subsystem.
>
> Last time I heard, storing electricity efficiently is an unsolved problem.
>
> (Apparently current battery solutions aren't very efficient.)
>
Yeah, that is the biggest hang up. One company though is looking to use 
the panels to split water, then store the hydrogen in a regular fuel 
cell. This can't, obviously, be too helpful for thing that need to be 
"on" all the time, but.. in principle, for anything that needs to only 
operate as needed, this would reduce costs quite a bit, since all you 
need it to make sure it has water to work with.

Still, the major break throughs are going to have to be in battery tech, 
and in making those solar cells both cheaper, and more powerful. The 
former being, maybe, easier than the later. There are people working 
with organic dye cells, which you can make damn cheap (but don't work as 
well as normal ones yet), and others that think they may have ways to 
make the silicon they are made on *way* cheaper.

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On 4/15/2011 19:57, Patrick Elliott wrote:
> The problem isn't nuclear explosions, its hydrogen generated by the system,

Are you talking about the alpha radiation or something?  I can't imagine 
where hydrogen would come from unless they're cracking water or something.

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

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