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PostPosted: Aug 05, 2014 2:09 am 
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http://www.rosatom.ru/en/presscentre/news/7cb97d0044e7987bb28eb32411160940

Chinese and russians getting together on this now. Though I suspect the usual cycle of joint work (chinese build the barge shell and balance of plant, russians provide the reactor?), then license build in china, then magically domestic orgin tech chinese domestic production...

That said, factory construction of nuclear power barges is desirable, and the chinese are certainly in a good position to enable that. I can easily see an extension of this into foreign policy work in africa, where there are a number of major port development projects supported by chinese foreign aid packages. Slipping in a power plant into the deal would sweeten things, and allow repossession if the africans get behind on their payments.


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PostPosted: Aug 06, 2014 12:58 pm 
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The Chinese could possibly make a business out of supply of full power plant off the shelf (Anchor, really). They could offer a lease where capital cost in advance is a problem.


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PostPosted: Sep 28, 2014 11:05 pm 
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Here is another news item on the subject:-
http://www.wantchinatimes.com/news-subc ... 4&cid=1101
A medium scale nuclear plant may have a good market. A 500MW plant could be 'Temporarily' anchored at the point of load and continue till required for refueling.


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PostPosted: Aug 13, 2017 2:25 pm 
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FYI,

This week's issue of The Economist has an article about floating nuclear power plants. Several concepts are discussed, from France (Flexblue), Russia and China:

Atomic power stations out at sea may be better than inland ones


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PostPosted: Aug 15, 2017 8:14 am 
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Thanks Camiel!

I wonder why there has been no/little work on floating larger reactors? It would seem fairly obvious, with the large size of modern ships (cruise ships, mega oil tankers), there really isn't much of a size limitation. The whole "road transportable" size constraint that many SMRs use wouldn't apply to a floating nuclear powerplant, for example.

Could one fit an ESBWR on a ship without significant design changes? That'd be a fun exercise.


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PostPosted: Aug 15, 2017 11:30 am 
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There is the Prelude Floating LNG production platform that is either under construction or is fitting out (can't remember which) which displaces something like six hundred kilotons.

This paper says that an ESBWR contains about fifty thousand tonnes of metal and a hundred thousand cubic metres of concrete - which is going to mass about 300 kiloton.
So I would say yes.


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PostPosted: Aug 15, 2017 2:39 pm 
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E Ireland wrote:
There is the Prelude Floating LNG production platform that is either under construction or is fitting out (can't remember which) which displaces something like six hundred kilotons.

This paper says that an ESBWR contains about fifty thousand tonnes of metal and a hundred thousand cubic metres of concrete - which is going to mass about 300 kiloton.
So I would say yes.


Then bring on the twin ESBWR ship!!

The prelude isn't cheap though; likely will come in little over 12 billion. Still for 3100 MWe (2x1550) this would be quite a good deal. ESBWR sure looks a lot simpler than that crazy complicated LNG stuff. Besides the ESBWR can be uprated with larger last stage turbine blades and other improvements.


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PostPosted: Aug 15, 2017 2:51 pm 
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How much concrete would you need for a ship ESBWR? Probably a small fraction - don't need basemat, can use steel plate ship construction for the cells, containment, heck probably even the pressure vessel (check out submarine hull construction). That ought to know down the concrete by factor 2-3. Maybe even more if you use water tanks for bio shields rather than concrete.

Then again steel use might go up. Still it would be good for weight - 50% more steel and 1/3 the concrete cuts it down to some 160 kton. Even with 10 kton of water still only 170 kton.


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PostPosted: Aug 15, 2017 6:26 pm 
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Well most of the steel and concrete is not actually in the reactor module itself, its in things like the radwaste building and turbine hall.

Since the reactor and its structures are heavy you will want them really low in the water for stability - which also allows the water to help shield against aircraft impacts etc.

Also potentially the isolation condenser tanks could be below the waterline, with the turbine structure on top.
If the IC tanks are below the waterline maybe you should make the condensers out of a salt water resistant alloy (or provide electrolytic corrosion suppression) and not have tanks at all, just a moon pool.

Unlimited cooling water.

It also depends how much open water this station could tolerate - if you could anchor in a kilometre of water you could probably still pass HVDC to the shore but you would have access to 3-4C water all year round. (Turn it into a tension leg platform?)
And since you would be pumping pretty much straight up in a huge diameter plastic film 'pipe' with struts keeping open, you can have a huge hydraulic diameter and hold your pumping power right down - allowing much lower delta-Ts.

Maximum condenser vacuum!


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PostPosted: Aug 15, 2017 8:32 pm 
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E Ireland wrote:
Well most of the steel and concrete is not actually in the reactor module itself, its in things like the radwaste building and turbine hall.

Since the reactor and its structures are heavy you will want them really low in the water for stability - which also allows the water to help shield against aircraft impacts etc.

Also potentially the isolation condenser tanks could be below the waterline, with the turbine structure on top.
If the IC tanks are below the waterline maybe you should make the condensers out of a salt water resistant alloy (or provide electrolytic corrosion suppression) and not have tanks at all, just a moon pool.

Unlimited cooling water.

It also depends how much open water this station could tolerate - if you could anchor in a kilometre of water you could probably still pass HVDC to the shore but you would have access to 3-4C water all year round. (Turn it into a tension leg platform?)
And since you would be pumping pretty much straight up in a huge diameter plastic film 'pipe' with struts keeping open, you can have a huge hydraulic diameter and hold your pumping power right down - allowing much lower delta-Ts.

Maximum condenser vacuum!


Pulling up deep ocean water for cooling will also have the side effect of being an artificial upwelling, with knockon effects for local sealife/aquaculture. OTEC advocates frequently harp on this as a secondary income stream.


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PostPosted: Aug 16, 2017 7:37 am 
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Quote:
Well most of the steel and concrete is not actually in the reactor module itself, its in things like the radwaste building and turbine hall.


Can cut down weight here in the same way, make steel plate walls, weld into cells, use water in double walled cells for shielding.

Quote:
Since the reactor and its structures are heavy you will want them really low in the water for stability - which also allows the water to help shield against aircraft impacts etc


Yeah, that's a good layout plan. I think if you use a double outer hull and then backfill with concrete it would do pretty well in an aircraft crash in terms of penetration. In terms of global loading, a big advantage will be that the ocean/sea actually acts as a giant seismic isolator, except it is even better since it can dissipate much better.

Quote:
Also potentially the isolation condenser tanks could be below the waterline, with the turbine structure on top.
If the IC tanks are below the waterline maybe you should make the condensers out of a salt water resistant alloy (or provide electrolytic corrosion suppression) and not have tanks at all, just a moon pool.


Interesting idea! That would do away with the large volume of water needed at the top pools level. Could do away with a lot of equipment such as the IC/PCCS expansion pools and their valves, liners etc. On the negative it probably requires titanium alloy or some other fancy material for the IC tubing, but that's a minor cost (they're already high nickel alloy in the ESBWR). Impressed current or zinc nodes would be effective enough for the pool liner.

Boiling seawater seems a little awkward though, wouldn't you get salt and organics everywhere? Or deposits on the tubes? Also there'd better be some grating in the moon pool inlet or else you'll find you're boiling fish. Surf and grub for the sailor crew!

Personally I prefer the Kerena approach, where there is a more passive IC in the containment (emergency condenser) that boils water in a pool in the containment, then you'd only have the containment cooling tubes in the seawater pond.

Quote:
It also depends how much open water this station could tolerate - if you could anchor in a kilometre of water you could probably still pass HVDC to the shore but you would have access to 3-4C water all year round. (Turn it into a tension leg platform?)
And since you would be pumping pretty much straight up in a huge diameter plastic film 'pipe' with struts keeping open, you can have a huge hydraulic diameter and hold your pumping power right down - allowing much lower delta-Ts.

Maximum condenser vacuum!


Yeah that would work. Combined with bigger last stage turbine blades this could be amazing in terms of efficiency. You can just anchor it to those depths, no need for fancy tension legs or anything, just a swivel turret and a big chain anchor. but you'd need to be really far out into the ocean for most locations. It would cost a lot in terms of transmission of power and flying crew in and out. I'm guessing you want to stay within 20 km or so of the shore, probably closer even. Obviously wouldn't work for the North Sea!


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PostPosted: Aug 16, 2017 12:04 pm 
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Cyril R wrote:
Boiling seawater seems a little awkward though, wouldn't you get salt and organics everywhere? Or deposits on the tubes? Also there'd better be some grating in the moon pool inlet or else you'll find you're boiling fish. Surf and grub for the sailor crew!

I'm not sure the water would actually boil though unless the moonpool entrance to the sea was very small - I think its more likely that wave action could be induced to move water in and out of the system, even if the delta-T between the sea is only 20-30C, it is quite easy to imagine being able to remove the shutdown power like that.
The 'tank' would never reach the boiling point.
Cyril R wrote:
Yeah that would work. Combined with bigger last stage turbine blades this could be amazing in terms of efficiency. You can just anchor it to those depths, no need for fancy tension legs or anything, just a swivel turret and a big chain anchor. but you'd need to be really far out into the ocean for most locations. It would cost a lot in terms of transmission of power and flying crew in and out. I'm guessing you want to stay within 20 km or so of the shore, probably closer even. Obviously wouldn't work for the North Sea!


A tension leg structure has the advantage that it effectively eliminates pitch and roll however - which simplifies the design of the reactor as we don't have to worry about water sloshing in the pressure vessel and causing erroneous water level readings, and stuff like that.

Well if we anchor in 1000m deep water right at the southwestern tip of the UK's EEZ (our EEZ runs out just as the shelf goes off a cliff), then you will be 200 nautical miles or so from the nearest land in the UK that you could base people on (The Scilly Isles), which also happens to be one of the local authority areas in the UK with a projected-to-fall population, so the economic uplift from the plant might prove useful.

HVDC Light subsea links are up to 500kV now, and that can handle the output of an ESBWR fairly easily, a pair of dipoles would probably not cost an enormous sum and ~360km to shore is not such an unimaginable distance. And since the cable would be running over the shelf it would be in relatively shallow waters for almost all of the route.

600kV and ~2300MWe per link is probably within reach, and remember that HVDC Dipoles are now sufficiently cheap to install that things like the Western Link are being built to avoid building power lines on land in the UK (largely because of NIMBYs).

If we are pushing to something like ten millibar vacuum (~7C condensing temperature by using direct contact condensers and PCHEs with huge amounts of ~4C seawater) then we could be looking at 70MWe net additional on an ESBWR, if my numbers are halfway correct.


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PostPosted: Aug 16, 2017 1:02 pm 
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Quote:
I'm not sure the water would actually boil though unless the moonpool entrance to the sea was very small - I think its more likely that wave action could be induced to move water in and out of the system, even if the delta-T between the sea is only 20-30C, it is quite easy to imagine being able to remove the shutdown power like that.
The 'tank' would never reach the boiling point.


I wouldn't be too sure of this, it would require very specific engineering of the cooling paths. Thermal stratification would want to keep the hot water on top of the moon pool. Water comes in from the bottom. This is a stagnation situation.

Quote:
A tension leg structure has the advantage that it effectively eliminates pitch and roll however - which simplifies the design of the reactor as we don't have to worry about water sloshing in the pressure vessel and causing erroneous water level readings, and stuff like that.


The thing still has to be assembled in a shipyard and brought to location - so it needs to stand on its own so to speak with regards to everything the ocean can throw at it. Sloshing seems low for a big ship like this, if they can make LNG work it wouldn't be an issue. Probably take 10-20 second average level readings to avoid erroneous readings. ESBWR has timers for the safety systems and the PPPTs in Kerena would be inherently delayed by heat capacity.

Quote:
HVDC Light subsea links are up to 500kV now, and that can handle the output of an ESBWR fairly easily, a pair of dipoles would probably not cost an enormous sum and ~360km to shore is not such an unimaginable distance. And since the cable would be running over the shelf it would be in relatively shallow waters for almost all of the route.

600kV and ~2300MWe per link is probably within reach, and remember that HVDC Dipoles are now sufficiently cheap to install that things like the Western Link are being built to avoid building power lines on land in the UK (largely because of NIMBYs).

If we are pushing to something like ten millibar vacuum (~7C condensing temperature by using direct contact condensers and PCHEs with huge amounts of ~4C seawater) then we could be looking at 70MWe net additional on an ESBWR, if my numbers are halfway correct.


Question is, is it worth it? Sounds very similar in terms of cost to the NorNed cable.

https://en.wikipedia.org/wiki/NorNed

Longer length, but smaller capacity so a reasonable proxy. It costs 600 million euros. Not a good deal for 70 MWe more - and that is before considering trans losses which are over 4% for NorNed. With shorter line and larger cap maybe looking at 2%? Even that is significant, over 30 MWe loss. Installing a 1000 meter deep shroud is going to cost money too - can't build it in the shipyard.

A lot of other costs go up as you go further out to the ocean. Some of it isn't immediately obvious. Flying in crews and equipment can run into serious numbers for remote applications. The fact that it becomes remote means you won't fly everyday, so you end up with the high cost structure that remote mines and oil platforms have: 1-2 weeks in, 1-2 weeks out, need to pay workers a lot of money for under the usual 40h/week.

My guess is before all is said and done, you'd be looking at > $1 billion added and more during operations. A poor deal for maybe 50 MWe added tops considering losses.


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PostPosted: Aug 16, 2017 1:10 pm 
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To me, a relatively shallow sea or ocean location is very interesting, not just because of proximity to the shore, but also because one major concern often repeated against ship reactors is "what if they sink?". If the location is say 10 meters deeper than the ship, then (for a big ship like this) it would never actually sink - if there is a leak so bad it exceeds any mitigation, it will just land on the bottom of the sea/ocean bed, allowing easy and safe recovery/salvage. So I would definately be looking for continental shelfs as the prime location.


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PostPosted: Aug 16, 2017 5:15 pm 
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Well if an ESBWR sinks the IC condensers will be submerged forever, and being two hundred miles from shore effectively eliminates any chance of ever needing a Fukushima and Chernobyl style exclusion zone.

Apparently experience in the North Sea Oil industry has indicated that water at depth, like that off Norway, has a lower fouling potential than shallower water, apparently it has less biofilm forming bacteria and crustacean/coral formers.

Additionally turret moorings are quite problematic - the highest voltages available in modern electricity-transmission swivels for turret moorings are 66kV AC or 90kV DC [an example of the former].
You could put enough of the swivel rings in parallel to get the current capacity, but you would stil lhave to put HVDC systems or transformers on the swivel.

Which could get problematic, even though HVDC Light stations are relatively compact.

A spread moored or tension legged platform is in a fixed orientation so the cable can almost just be dropped over the side.


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