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nuclear powered steam powered unmanned flood tunnel digger---for digging water tunnels only

the most efficient way to dig major water tunnels
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  [vote for,

patents were filed decades ago for nuclear powered tunnel tiggers for massive tunneling machines. they never got off the ground for commercial purposes because of many reasons and complexities.

i was trying to conceive of a method to dig 100 kilometer long 1 foot diameter tunnel from ashkelon coastal israel mediterranean to the dead sea.

the nuclear powered digger would dig ever so slowly down wards ...as the landscape above it rises it would be 'deep' underground by many meter. by the end of 100 kilometers of digging , the tunnel endpoint would be 40 meters below sea level.

the tunnel entrance starts 10 meters below sea level just off the coast.

the nuclear powered digger actually just 'melts' through the earth by using the water that is constantly flowing to it from the entrance of the tunnel.

the diggers back end (facing the opening of the tunnel ) takes in water and uses its prolific heat to produce steam and super pressured water from this constant water flow to dig away at the leading edge of the tunnel.

using the particulate matter that it creates by digging away the tunnel---the digger than creates a hollow casing for the tunnel. the inside of the casing is the tunnel. the space between the inside and the outside wall is a honycomb space that provides strucutural integrity as well as an outlet for the excess particulate and excess heat and water flow-----to be carries out of the tunnel back to the leading edge entrance so that excess particulate has a way out of the tunnel. the excess heat helps produce a circulatory flow of water up and out of the leading edge of the tunnel to the entrance.

when the tunnel eventually reaches the 'surface' of the earth which should be around 50 meters below sea level -- -it can simply shut down its operations and allow the mediterranean to slowly and passively flood the dead sea basin which extends to 400 meters BELOW sea level. NO pumps, no waste energy.

the particulates and steam

teslaberry, Mar 07 2014

Mediterranean–Dead Sea Canal http://en.wikipedia...80%93Dead_Sea_Canal
"The approx 8 m diameter pressure tunnel is designed for a maximum flow rate of 2.5 m/s" [8th of 7, Mar 07 2014]

Red Sea–Dead Sea Canal http://en.wikipedia...80%93Dead_Sea_Canal
Alternative or complementary option. [8th of 7, Mar 07 2014]

NaK http://en.wikipedia.org/wiki/NaK
Lovely stuff. [8th of 7, Mar 07 2014]

2000 year old working acquaduct http://en.wikipedia.org/wiki/Pont_du_Gard
shallow acquaduct standard in roman times still works ---2000 years later! [teslaberry, Mar 09 2014]

vitruvius guide for gradient in acquaducts http://en.wikipedia...wiki/Roman_aqueduct
my tunnel is designed with roman expert engineering guidance for passive water bearing gradient . [teslaberry, Mar 09 2014]

Underwater Epoxy http://www.duckwork...rticles/underwater/
[scad mientist, Mar 12 2014]


       // 1 foot diameter //   

       The core of a Pu-burning NaK-cooled FBR is about 1.2m in diameter and 1.6m high. That's about as small as it's possible to make a fission reactor; if you want to use thermal neutrons that means a moderator is needed, which adds a lot if bulk.   

       It's not going to go through a 300mm hoop ...   

       If you're going to drive a tunnel, make it big enough to easily maintain.   

       The "fall" on the tunnel needs to be as steep as possible allowing for the level of the Dead Sea. That way you get a lot of hydro power as well as decreasing the salinity.
8th of 7, Mar 07 2014

       //Pu-burning NaK-cooled//   

       sP: pu-burning nak-cooled.
MaxwellBuchanan, Mar 07 2014

       Plutonium: symbol "Pu"
Sodium: symbol "Na"
Potassium: symbol "K"

       The eutectic alloy used for reactor cooling is generally referred to as NaK.   

8th of 7, Mar 07 2014

       dO geT witH iT, 8tH.
MaxwellBuchanan, Mar 07 2014

       Hmm, suspect quite a few middle east countries would chip in for the Project Orion version of this.
not_morrison_rm, Mar 07 2014

       I think it's pretty cool that the water used in the tunneling ops is so abrasive that it just cuts right through the rock - but after construction, it flows smoother than a warm silicone implant down a low- latency wifi connection. It'd be pretty unfortunate if it were to cut an unsightly and unplanned canyon from the Med to the Dead...
lurch, Mar 08 2014

       Hang on, GPS doesn't work underground, so what's the stop it veering off-course and undermining Crimea....or is that a bit of a win-win.
not_morrison_rm, Mar 08 2014

       //so what's the stop it veering off-course //   

       Civil engineering projects like tunnelling now use laser systems to provide location data using the portal as the datum line, having verified its position with DGPS.
8th of 7, Mar 08 2014

       It seems like making it autonomous is more complex than needed. I wonder about the practicality of making anything out of wet talings. Maybe just wash them out with a sucker. And if you have a sucker you might as well have a power cable. Then you could leave out the reactor and still have room for a mini fridge.
bungston, Mar 08 2014

       Unless it's deep, or hard rock, or very wet strata, cut-and-cover has a lot to commend it.
8th of 7, Mar 08 2014


       So that explains the lack of progress in the England to Ireland tunnel
not_morrison_rm, Mar 08 2014

       If it's built, it will actually be a Scotland-to-Ireland tunnel, very roughly Stranraer to Larne (and they're welcome to it).
8th of 7, Mar 08 2014

       cut and cover is not only super laborious, but more problematic you need permission from land owners of MANY sorts along the route. same problem with getting easements in making pipelines.   

       the problem with piping water to dead sea is you cannot pipe any reasonable amount of water because of the electrical pumping needs. running a 'negative pressure' pipe over land with multple junctions and turns in the pipe itself is not gonna happen---so you need to use electricity to pump massive quantities of water. this is too energy intensive.   

       finally---if you dig a passive STRAIGHT tunnel that goes down a gradient, you cna presumably use some of the water pressure at the first few hundred meters of the exit of the tunnel to desalinate some of the water.   

       some suggest you dig the tunnel as deep as possible but that's even more expensive as earth gets more compacted. ALSO---any remote possibility of wireless communication to a subsurface 'guided' digger is reduced the deeper the digger goes.   

       i think at 50 meters--the digger can probably receive an low frequency sonic or electromagnetic signal telling it to go left or go right.   

       the deeper you go less so.   

       and most importantly. if you're digging a passive tunnel with sluice gates, the pressure builds at the exit the deeper it is. a sluice gate at 400 meters is holding back higher pressure and more prone to catastrophic failure.   

       a sluice gate at 50 meters is just going to be a fluid outlet that creates a river of less saline sea-water that flows to the lowest point of the dead sea basin of 400 meters below sea level.   

       as you go north the dead-sea basin goes up the jordan river ( a sweet water river outletting from the kinneret gallillee lake. )   

       the kineret is at 210 meters below sea level and as the dead sea basin fills close to this level ( a massive amount of water would take years to fill it to this level never seen in history) ---it would slowly get brackish as the dead sea forms an estuary creeping northwards up the jordan.   

       once it starts aproaching the 250 meters below sea level mark---you are going to want VERY RElIABLE SLUICE GATES.   

       catastrophic failure is not great. most likely if the gates fail the only option is going to be to destroy the tunnel in multiple points by one of a variety of means.   

       in the unlikely event the pressure of the mediterranean pushed an aquifer through that rubble filling in the destroyed tunnel----YOU DONT want a high pressure leaky aquifier running any deeper than you need it to.   

       there are a number of mini canyon drainage vallies leading to the dead sea that are just opening at about 50 meters below sea level and they appear --in person --to look like the edge of of a cliff leading into a canyon , a smaller version of the lips of the grand canyon. much smaller.   

       I would say the golden rule is just do the minimum possible to solve the problem. doing the maximum just leads to more unitended consquences-- particularly in the case of geo-engineering.   

       the deeper and steeper you make those tunnels the more than can go wrong. the roman aquaduct construction legend--vitruvius-----actually notes the imporance of shallow gradients for long term stability of the acquaduct ( in his time there were not sensors and everything built by hand had to LAST )   

       he recommended no less   

       one of the oldest STILL WORKING roman aqaducts has a gradient almost identical to my proposed tunnel----dropping 34 centimeters for every kilometer ----( 34 meters per 100 kilometers is about what you get if your opening is at 10 meters below sea level and exit at 50 )   


       descending only 17 m vertically in its entire length of 50 km (31 mi): it could transport up to 20,000 cubic metres a day.   


       higher gradients lead to more pressure and sometimes were used for the purposes of hydraulic mining and power.   


       it is my opinion that the dead sea is a disaster and needs water desperately. the desert remains profiteable to certain intersts so long as it is kept stable enough for them to exploit it. well---that's been going on for decades and it has just made the problems far worse. eventually , when it comes to dessert it's just going to die from their drying the last drop of water.   

       the sad part is that all efforts to hydrate the dessertifying basis are of course---being directed and lobbyed by the very people who not only have created the problem---but who stand to gain from being able to direct and control any 'solutions' that can be built.   

       compromise sometimes is good for commercial purposes. but the dessert is a truly uncomprising force of nature. it is hard to fight, and the simply direct method is building a passive water conduit which introduces are far more powerful force of nature---the Mediterranean sea---to fight the dessert.   

       ===as far as the nuclear powered device is concerned---it would not go under ANY disputed land from gaza or west bank ( you can do a straight line under the continuous strip of land that is israel.   

       furthemore-----a digging device that goes straight and continuous without chanings will dig a far more stable tunnel, that operates with less problems, and can be dug faster than by other twisting means.   

       drop offs, conduits, junctions and sharp turns in tunnels are inherently unstable just as twisty rivers are unstable with shifting banks. A STRAIGHT SHOT WOULD DO IT. keep it simple stupid.   

       nuclear powered. might sound complex but it really doesn't have to be . you don't need as many moving parts as with a combustion engine.
teslaberry, Mar 09 2014

       What about a siphon?   

       Also, those //particulates and steam// look a bit lost. Do they have a home somewhere in the main text?
pertinax, Mar 09 2014

       //but the dessert is a truly uncomprising force of nature   

       Oooh, ooh, ooh....I want to say it, but I shouldn't say it...   

       Whips out Punners Anonymous card and starts saying "one day at a time, one day at a time.."
not_morrison_rm, Mar 09 2014

       As designed this sounds very unlikely to happen. You need to develope your small nuclear reactor as well as some method for converting your particular matter into a casing.   

       Here's an alternative: 1) Make it gas or diesel powered. 2) Build the casing and "material tubes" out of 2 part underwater epoxy.   

       As the device digs, it forms 5 small pipes and the main pipe.   

       Pipe 1 is used to pump fuel. Pipe 2 is used to pump air to run the engine combustion and waste removal. Pipe 3 is used to pumps in fresh water for engine cooling, hydraulic digging, and to provide water flow back out the main pipe to carry waste.   

       Pipe 3 and 4 are used to pump a two part underwater epoxy (link). These are mixed and used to form the casing.   

       The tubes are formed around smooth pipes hanging out the back of the digger that slide out of the pipes being formed. The expoxy is prevented from sticking to these pipes by giving the pipes the appropriate electrical charge. The underwater expoy link describes "cathodic issues" as a problem that can prevent the epoxy from sticking, but in our case we can use that problem to our advantage. Hopefully we could get a good enough seal and still be able to slide the tubes out of the newly formed tubes. This makes it very difficult for the digger to turn, but you wanted a straight pipe anyway, right?   

       To remove the waste material, we could try to push the dry material out through a tube by pumping lots of water with it, but the chance of cloggling seems very high in a tunnel that long. Instead, some epoxy should be used to construct small packages of dirt. Before sealing these, air from the air supply tube should be added to make it slightly boyant so it will float at the top of the tunnel up the slope of the tunnel as it flows along with the waste water. The pods of dirt should be small enough that if some break and sink, other pods floating along the top of the tube can easly clear them.   

       Generating one-time use epoxy pods is somewhat wasteful. Maybe reusable pods could be sent down the water pipe, filed with air and dirt, and sent back to the surface to be dumped.   

       Depending on the smoothness of your pipe, I calculate your flow rate for a 40m drop of 1 foot pipe over 100km to be between about 0.35m/s and 0.55m/s. That actually seems like a reasonable flow rate so that you're not getting extreme errosion of your pipe, but it seems like a rather small amount of water for a project of this scale. According to the first link, the dead sea has an evaporation rate of 60 - 70 cubic meters per second (5.2 million cubic meters a day). Your pipe might deliver 3150 cubic meters a day. Do you plan to go back and add multiple tunnels over time? Is there a reason for making it 1 foot in diameter rather than having it be larger? If you made the pipe larger but reduced the altitude drop to keep the flow rate the same, then although you need a larger valve to close the pipe, that value would have less pressure to hold back when closed. Whatever pipe size you choose, just be sure to close it very slowly or you will demonstrate water hammer VERY dramatically.
scad mientist, Mar 12 2014

       ... unless you put the valve at the upstream end of the pipe, and just create some vacuum.
8th of 7, Mar 12 2014

       To be honest, the best way would be to bury a line of secondhand warheads and then explode them to make a big ditch.   

       That does have some obvious problems. But, done correctly it would cut off the Gaza strip from the mainland.
not_morrison_rm, Mar 13 2014

       //That does have some obvious problems. //   

       Not to us ... please explain.
8th of 7, Mar 13 2014

       Well, that would Gaza into some kind of Venice, and the world is not ready for suicide gondoleers imho   

       (hang on, wasn't the bad guy The Mummy called imho-tep?)
not_morrison_rm, Mar 13 2014


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