Details On The WB-7 Experiments

[MSimon]

I agree with you Simon. But solving challenging problems is what makes engineering fun.
The SR-71 was "just engineering". They only had to invent several materials and develop
new engines. It was so amazing for its time it was kept secret to the people who paid for it.

FWIW I had (have?) a couple of lines of code in the SR-71.

I was not "cleared" for the job so it was done subrosa. I did the work. The guy assigned the effort signed the paperwork (he had a higher priority job to work on).

It was a small fix for a problem I don't even recall. 8080 code. I was (may still be) an expert on that machine since it was my first micro. IMSAI 8080.

[drmike]

Excellent! I worked on RR's Star Wars program and had a similar situation. I wrote up a bunch of physics, but wasn't allowed to present it because it was classified and I wasn't cleared! You gotta love the insanity of government. Otherwise you'll go crazy.

[JD]

Stored cold is not a useful concept for dissipating 20 MW in a running reactor.

Didn't say it was. I thought there might be ideas concerning design and insulation concepts that might be useful.

Unless the plan is to run the reactor for 5 or 10 - 1 sec pulses in a 10 hour period.

I doubt that was their concept but it's irrelevant since I'm not arguing their concept. Simply pointing out they may have some design/material concepts that might be useful.

In any case even 20 MJ for 1 second is likely to cause a superconductor explosion from stored magnetic energy.

Not arguing or advocating their concept. They thought perhaps they could stretch it into several hours which is why I pointed it out for the reasons mentioned above.

There is not going to be some magic bullet. We are going to have to extract the energy at around 600 deg K and keep the magnets below 20K. That is just a fact of life. It can be done (I'm convinced) it will just require some tricks - like an extra layer of coolant at 300K.

Which is why I originally mentioned this and the idea of a non conductive inner layer using a unpressurized coolant to take some of the load off the primary coil housing. I have no idea if such would be valuable or not but simply mentioned them to see if anyone found any value. My engineering never progressed beyond field fortifications or how to recover damaged armored vehicles in interesting circumstances.

The tough part will be getting all that squeezed in the right form factor.

Agreed.

Let me add that I do not in any way wish to discourage you from thinking of other concepts that might help. I will continue to raise objections (if I have any) until we come up with a good idea.

I have no animosity, unless you're secretly a sock puppet controlled by Paul Dietz.

Simply wasn't sure if I was making my reasoning plain in the earlier postings.

Science is hard. Engineering is harder.

I had more fun blowing things up. Artillery bursts in the dewy morning are beautiful. The momentary sphere of compressed moisture takes on a mirrored sheen for a fraction of a second. Quite surreal.

I always wanted to be a scientist when I grew up. I kind of fell into engineering. I think I like it better. The problems are harder.

I had neither the opportunity or resources. My oldest however is working on his masters program (not sure if he'll stay with mathematics or not). I have plans for my grandchildren, if health and resources hold out. If that seems domineering to some, well I grew up at a level of poverty few can even visualize, I will not have it happen to my decedents.

We are most fortunate that Dr. B was more of an engineer than a scientist. I'm sure he contemplated these problems and factored them into his research.

It would be interesting to see his private notes, if they're ever released. It is a bit concerning though in reference to mobile uses.

[MSimon]

My engineering never progressed beyond field fortifications or how to recover damaged armored vehicles in interesting circumstances.

Your own fire works show when ever uncle would pony up (probably frequently).

Wish I could have been there (well maybe not - I'd probably have been damp and brown - the pucker factor always adds interest to a situation).

I have a prejudice in favor of mil guys. They bring a level of seriousness to any situation that you rarely find in civies. Present company excluded of course. The people who have hung around here are some of the most serious I have had the honor to interact with.

Good luck with the grand kids. I have the honor of having #2 son graduate with honors from U Chicago this past June. No grand kids yet. Or any immediate prospects.

And FWIW I'm not Paul Dietz's sock puppet. :-)

[gblaze42]

There are things you can do. Making the reactor bigger for a given power out is one. Not the best one (for reasons of economics) but, you could do it.

The core problem (because of vacuum insulation) is radiation. Silvering (or aluminization, or gold coating etc.) of the inside of the pipes is one thing that will help.

I'm not sure I understand, silvering/gold coating would be helpful for EM radiation but if the major energy carrier was the Alpha particle it would wouldn't be, or am I missing something?

I would agree with you about having some kind of secondary heat exchange method such as water flowing rapidly through a secondary pipe that surrounds the magnets. Then it would have to be large enough to push enough water through to carry away ~20 MW of heat energy. Then again it won't all be in heat, if the material stopping the alpha particles gave up some of it's outer electrons when collided with by the alpha particles, the electrons could be possibly used.

If not the electrons could then dissipate the energy.

Just something to think about...

[MSimon]

There are things you can do. Making the reactor bigger for a given power out is one. Not the best one (for reasons of economics) but, you could do it.

The core problem (because of vacuum insulation) is radiation. Silvering (or aluminization, or gold coating etc.) of the inside of the pipes is one thing that will help.

I'm not sure I understand, silvering/gold coating would be helpful for EM radiation but if the major energy carrier was the Alpha particle it would wouldn't be, or am I missing something?

I would agree with you about having some kind of secondary heat exchange method such as water flowing rapidly through a secondary pipe that surrounds the magnets. Then it would have to be large enough to push enough water through to carry away ~20 MW of heat energy. Then again it won't all be in heat, if the material stopping the alpha particles gave up some of it's outer electrons when collided with by the alpha particles, the electrons could be possibly used.

If not the electrons could then dissipate the energy.

Just something to think about...

Let me see if I can clarify. The magnet will consist of a series of concentric pipes. The innermost will contain the superconductor and its coolant at 20K. Next will come a vacuum space and next will come LN coolant. In the vacuum space between the superconductor coolant and the LN coolant the walls will be silvered (or some such) to minimize the radiative heat flow between the superconductor coolant and the LN. Think thermos bottle.

Next space after LN coolant will be another vacuum space. It too will be silvered. Then H2O coolant at around 300K. Another silvered vacuum space. And finally H2O coolant at around 600K.

What we are going to have is a series of concentric vacuum bottles with LHe at 20K at the center and H2O at 600K at the outside. All this plumbed to allow enough flow to keep everything at the proper temperature.

Let me add that any electrons ejected from the surface of this contraption will carry away minimal energy. The alphas will be hitting with 2MeV+. The electrons (those that are not lost due to high energy) will be at 50KeV.

My current plan is to coat the outer surface of the coils with Boron which melts at 2349 K. The purpose is to prevent sputtering of the metallic pipes holding the coolant so the only material sputtered into the reactant space will be a reactant - B11.

We will have to figure out how to balance Boron condensation on the outer magnet structure with Boron sputtering from the reaction.

More engineering fun!

[gblaze42]

Let me see if I can clarify. The magnet will consist of a series of concentric pipes. The innermost will contain the superconductor and its coolant at 20K. Next will come a vacuum space and next will come LN coolant. In the vacuum space between the superconductor coolant and the LN coolant the walls will be silvered (or some such) to minimize the radiative heat flow between the superconductor coolant and the LN. Think thermos bottle.

Next space after LN coolant will be another vacuum space. It too will be silvered. Then H2O coolant at around 300K. Another silvered vacuum space. And finally H2O coolant at around 600K.

What we are going to have is a series of concentric vacuum bottles with LHe at 20K at the center and H2O at 600K at the outside. All this plumbed to allow enough flow to keep everything at the proper temperature.

Let me add that any electrons ejected from the surface of this contraption will carry away minimal energy. The alphas will be hitting with 2MeV+. The electrons (those that are not lost due to high energy) will be at 50KeV.

My current plan is to coat the outer surface of the coils with Boron which melts at 2349 K. The purpose is to prevent sputtering of the metallic pipes holding the coolant so the only material sputtered into the reactant space will be a reactant - B11.

We will have to figure out how to balance Boron condensation on the outer magnet structure with Boron sputtering from the reaction.

More engineering fun!

Nicely done! I'm wondering, would the increase of cross section with so many concentric pipes increase the energy deposited by the alpha particles? or is that all part of the ~20Mw that you had mentioned before?


Thanks! It's good to flex the old grey matter, specially with someone well versed in engineering.

[MSimon]

The 20 MW is supposed to cover the total from alpha impingement.

Of course all that is dependent on getting the engineering balance right.

Once (if) it works it will seem obvious. Right not it is not so obvious.

[windmill]

One possible way to increase the cooling capacity of the system without increasing the cross sectional area might be to use the winding armature/support structure of the coils as a heat sink that is actively cooled externally to the vacuum vessel. I believe this idea has been used in spaceborne SC magnets.

[MSimon]

No possibility you can get enough heat out that way. Metals are not nearly conductive enough. Pumped fluids are the way to go.

[bishopj]

Let me see if I can clarify. The magnet will consist of a series of concentric pipes. The innermost will contain the superconductor and its coolant at 20K. Next will come a vacuum space and next will come LN coolant. In the vacuum space between the superconductor coolant and the LN coolant the walls will be silvered (or some such) to minimize the radiative heat flow between the superconductor coolant and the LN. Think thermos bottle.

Next space after LN coolant will be another vacuum space. It too will be silvered. Then H2O coolant at around 300K. Another silvered vacuum space. And finally H2O coolant at around 600K.

What we are going to have is a series of concentric vacuum bottles with LHe at 20K at the center and H2O at 600K at the outside. All this plumbed to allow enough flow to keep everything at the proper temperature.

Let me add that any electrons ejected from the surface of this contraption will carry away minimal energy. The alphas will be hitting with 2MeV+. The electrons (those that are not lost due to high energy) will be at 50KeV.

My current plan is to coat the outer surface of the coils with Boron which melts at 2349 K. The purpose is to prevent sputtering of the metallic pipes holding the coolant so the only material sputtered into the reactant space will be a reactant - B11.

We will have to figure out how to balance Boron condensation on the outer magnet structure with Boron sputtering from the reaction.

More engineering fun!

I'm a newbie here and have been trying to follow all of the discussion, so bear with me. Is there any type of sketch which shows this type of layout? The heat removal seems to be one of the largest enginneering issues remaining, assuming that the physics works as advertised.

[MSimon]

I should do a dwg.

However all you would see is a bunch of concentric circles.

I just did a sketch. I'll post it in a bit.

[MSimon]

[TallDave]

That's interesting. Is the concentric-pipes cooling method common? It seems like it might present problems in manufacture and maintenance.

I can't recall seeing it before, but my engineering experience is barely hobby-level. For all I know most superconducting magnets are cooled this way. Just wondering if this is something tried-and-true or bleeding-edge, relatively speaking.

[MSimon]

That's interesting. Is the concentric-pipes cooling method common? It seems like it might present problems in manufacture and maintenance.

I can't recall seeing it before, but my engineering experience is barely hobby-level. For all I know most superconducting magnets are cooled this way. Just wondering if this is something tried-and-true or bleeding-edge, relatively speaking.

Yep. Superconducting magnets are done this way. And yep. manufacturing will be a trick.

If it was straight pipe - no problem. It is the curves that are tough.