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Arguments for not building BFRs

Posted: Sat Nov 01, 2008 7:10 pm
by rj40
Assuming BFRs work as we all hope, what are some of the potential arguments against integrating working BFRs into human society? Not just stuff that would be easy to shoot down, at least to your average voter, but tougher arguments.

They mention some place called the Mojave Desert as being a principle mining area:
http://www.mininglife.com/commodities/b ... igures.htm
:-)

I think Tom Ligon mentioned this too.

Are there any lobbies trying to stop Boron mining and processing at this time? Perhaps we should get a list together of any that are. And then plot it against time. Why do I have the sinking feeling that anti-boron lobbies might grow.

Posted: Sat Nov 01, 2008 8:28 pm
by scareduck
The main argument against not building BFRs is that we have no idea if they will work. The physics are insanely complicated.

As far as boron deposits are concerned, there's enough in Inyo County alone to fuel the United States (probably the world) for centuries.

Posted: Sat Nov 01, 2008 8:47 pm
by MirariNefas
How strong will the magnetic fields around a polywell be? Will they largely cancel outside of the device, and how fast will field strength drop off? If you have a sufficiently large magnetic field that it extends well beyond the boundaries of your generator, people might get concerned that it'll confuse birds or somehow be related to a health effect of some kind.

Of course, if people were really concerned about magnetic fields, nobody would be building those maglev trains. So maybe not.

Posted: Sat Nov 01, 2008 11:13 pm
by blaisepascal
MirariNefas wrote:How strong will the magnetic fields around a polywell be? Will they largely cancel outside of the device, and how fast will field strength drop off? If you have a sufficiently large magnetic field that it extends well beyond the boundaries of your generator, people might get concerned that it'll confuse birds or somehow be related to a health effect of some kind.

Of course, if people were really concerned about magnetic fields, nobody would be building those maglev trains. So maybe not.
People generally aren't concerned about large magnetic fields because magnetic fields are usually "residual fields", cause by a local condition and naturally cancels with distance. Magnetic fields are, quite literally, the result of a relativistic change of reference frame of an electric field. Except in the case of EM wave propagation, they quickly fall off and act as short-range forces.

Dipole fields (as from a typical solonoid) fall off with an inverse r cubed relationship. Quadrupole fields fall off with an inverse r^4 relationship. The field configuration in the WB-7 is complicated, but seems vaguely like 3 interacting quadrupole fields. Although the field is intense at the center of the device, I'd expect the field to fall off dramatically even by the time it gets to the walls of the reactor, and be nearly undetectable outside of the shielding.

Another way to describe it is that the magnetic fields involved are on the same scale as those in an MRI machine. And those don't pose environmental problems.

Posted: Sat Nov 01, 2008 11:57 pm
by Jboily
blaisepascal wrote:Another way to describe it is that the magnetic fields involved are on the same scale as those in an MRI machine. And those don't pose environmental problems.
To be precise, it seems a field about 10 Tesla or larger can have some effect on the immune system response. However, It is very difficult to maintain a field of that strength inside a machine, the field outside the machine do drop very quickly to negligible value. It is also quite easy to add a shield if necessary. It would most likely be done to protect the equipment, as some are much more affected by the stray fields then any life form would be.

Posted: Sun Nov 02, 2008 12:09 am
by Aero
I just paid less than $4.00 for 5 pounds of Sodium tetraborate decahydrate,
that is, Na2B4O7.10(H2O) . Twenty Mule Team Borax. How much did it cost for the boron? And did I get B11 or another flavor.

Posted: Sun Nov 02, 2008 12:26 am
by Torulf2
There is a theory that global warming not comes from greenhouse gas but from the heat produced by fossil fuel burning and nuclear reactors, and the heat from devises using the energy from this sources. If so, fusion would not be a bright idea.
But these seams not are so likely. But some environmentalists maybe change their ideas of the nature of the global warming.

Posted: Sun Nov 02, 2008 1:27 am
by rj40
Thanks.

Is there anything about the construction of a BFR (as supposed today) that might raise some concerns? Are any of the constructions materials, and related chemical composition, dangerous to people to such an extent that the program would be left wide open to someone trying to shut it down?

Posted: Sun Nov 02, 2008 1:54 am
by tombo
I think it's going to be devil in the details time.
It depends on what exotic materials we need for superconductors, high temp grids, high performance insulators, first wall etc,
Boron in metallic form (reduced), as proposed for first wall issues, is not good for living things.
Cryogenic BLEVE's are a serious safety hazard but should not be much harder to design for than steam boilers, which were quite a hazard 100 years ago.
Although the bright boys a CERN seemed to have a little problem along those lines a few weeks ago.
Almost as embarrassing as the magnets that were not designed to withstand magnetic forces in the same project.

One of my fears is that someone will try to sweep some problem under the rug and when found by the political opponents used as evidence of other hidden problems. And lawyers with litigation "scientists" can always find something to object to.
Particularly, we need to do our due diligence on the radioactive nuclides induced by the side reaction neutrons out in the open so no one can say we are hiding something dangerous.

A bonus to having the Navy do the first ones is they will have to solve the safety problems before they can put them in close proximity to personnel on submarines & ships.

Posted: Sun Nov 02, 2008 3:09 am
by blaisepascal
Aero wrote:I just paid less than $4.00 for 5 pounds of Sodium tetraborate decahydrate,
that is, Na2B4O7.10(H2O) . Twenty Mule Team Borax. How much did it cost for the boron? And did I get B11 or another flavor.
A mole of Sodium tetraborate decahydrate masses (2*23.0 + 4*10.8 + 17*16+20*1 = ) 381.2g, of which 42.2g, or 11%, is Boron. So 8.8 ounces of the box is boron. 80.1% of that is B11, with the remaining 19.9% B10. So for $4 you bought 7.0oz of B11, 1.8oz of B10, and 4lb7.2oz of other stuff.

But it's going to cost you much more than $4 to separate out the B11.

Posted: Sun Nov 02, 2008 3:15 am
by Aero
Yea, and the 7 oz. won't even fuel my BFR for a full day. Or will it?
Tut tut - The cost of fuel these days ...

Posted: Sun Nov 02, 2008 3:24 am
by MirariNefas
Torulf2 wrote:There is a theory that global warming not comes from greenhouse gas but from the heat produced by fossil fuel burning and nuclear reactors, and the heat from devises using the energy from this sources. If so, fusion would not be a bright idea.
This isn't a theory in the scientific source though, and not something taken seriously in any mainstream capacity (not even by greenpeace, as far as I know). I've heard people think this, but any expert can manage the math to show that this effect is negligible. It wouldn't be a small accumulating effect either, as the world is so good at radiating heat into space.

Posted: Sun Nov 02, 2008 3:57 am
by blaisepascal
Aero wrote:Yea, and the 7 oz. won't even fuel my BFR for a full day. Or will it?
Tut tut - The cost of fuel these days ...
I get:

Code: Select all

blaisepascal@hacek:~$ units
2445 units, 71 prefixes, 33 nonlinear units

You have: 7oz 8.3MeV avogadro mol/(11g)
You want: MW d
	* 167.2156
So a $4 box of 20 Mule Team Borax has enough B11 to fuel a 100MW BFR for about 40 hours continuous operation.

Assuming my calculations are right.

Posted: Sun Nov 02, 2008 5:17 am
by choff
I've had a hard time finding 20 Mule Team Borax the last few years, somebody said there was a strike at the Borax mine. When I was a kid you could get a 20 Mule team model kit. Anybody know if they're still available?

Posted: Sun Nov 02, 2008 8:58 am
by olivier
You have the choice of boron capsules from New Zealand (against arthritis, boron rods in UK (used to protect timber, NOT suitable for the control of a chain reaction)... and many more forms of boron available from the Turkish government since Turkey has by far the largest resources in the world. The day when pB11 is proven to work as a source of energy, Turkey's candidacy for EU membership and for the UN security council shall make a giant step forward.