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Wikipedia & Universe
Post subject: Practical Nuclear Merchant VesselPosted: September 24th, 2017, 9:09 pm
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When I have a bit more time, I'm looking to start working on a design for a modern, practical nuclear-powered merchant vessel that can be produced in numbers. I'm starting with a general vision rooted in real-life proposals in the hopes of getting some feedback from the community before I start the design itself.

The basic outline is along the lines of this (emphasis mine):
Quote:
In November 2010 British Maritime Technology and Lloyd's Register embarked upon a two-year study with US-based Hyperion Power Generation (now Gen4 Energy), and the Greek ship operator Enterprises Shipping and Trading SA to investigate the practical maritime applications for small modular reactors. The research intended to produce a concept tanker-ship design, based on a 70 MWt reactor such as Hyperion's. In response to its members' interest in nuclear propulsion, Lloyd's Register has also re-written its 'rules' for nuclear ships, which concern the integration of a reactor certified by a land-based regulator with the rest of the ship. The overall rationale of the rule-making process assumes that in contrast to the current marine industry practice where the designer/builder typically demonstrates compliance with regulatory requirements, in the future the nuclear regulators will wish to ensure that it is the operator of the nuclear plant that demonstrates safety in operation, in addition to the safety through design and construction.

Nuclear ships are currently the responsibility of their own countries, but none are involved in international trade. As a result of this work in 2014 two papers on commercial nuclear marine propulsion were published by Lloyd's Register and the other members of this consortium.[6][7] These publications review past and recent work in the area of marine nuclear propulsion and describe a preliminary concept design study for a 155,000 dwt Suezmax tanker that is based on a conventional hull form with alternative arrangements for accommodating a 70 MWt nuclear propulsion plant delivering up to 23.5 MW shaft power at maximum continuous rating (average: 9.75 MW). The Gen4Energy power module is considered. This is a small fast-neutron reactor using lead-bismuth eutectic cooling and able to operate for ten full-power years before refueling, and in service last for a 25-year operational life of the vessel. They conclude that the concept is feasible, but further maturity of nuclear technology and the development and harmonisation of the regulatory framework would be necessary before the concept would be viable.
The main difference is that I plan to draw an operational container/bulker ship rather than a prototype based on an oil tanker, working from the assumption that all the regulatory challenges have been sorted out. Beyond that, the overall target is as follows:
  • Large, practical, commercially feasible nuclear-powered merchant vessel to improve and decarbonize shipping
  • Ideally utilizing a Gen4-type LFR with uranium nitride fuel to support cogeneration and long operational times without refueling, combined with an IFEP system to support freedom of placement of the reactor independent of the propulsion system
  • Generally cleaner-looking and "prettier" than other merchant vessels, but not so much so that it compromises its utility. So roughly inspired by the layout of this thing (albeit with more space devoted to cargo capacity and less to whatever's in that huge superstructure). But definitely not another NS Savannah, which was explicitly designed to be more political than practical.
  • If possible, having a modular common hull base design that can be adapted for container, bulker, RORO, etc. variants in various sizes
  • The latest safety features for protecting against corrosion and common sinking risks for merchant vessels, perhaps even ICCP if there's enough excess power

Any comments on the above points, or further suggestions for the design of the vessel, would be immensely appreciated. I'm trying to avoid getting "married" to a specific design before hearing from the community.

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acelanceloet
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 24th, 2017, 9:52 pm
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could you provide some source material for said reactor and possibly the article you cut the quote from?
this sounds interesting, I might work on something for this, but I have to say one thing: nuclear ships, with enough power for their entire service life, will most likely not be streamlined or otherwise made super fancy.....

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Wikipedia & Universe
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 24th, 2017, 10:41 pm
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acelanceloet wrote: *
could you provide some source material for said reactor and possibly the article you cut the quote from?
I thought the citation links from the Wikipedia article were both dead, but apparently one of them is still working: http://www.sciencedirect.com/science/ar ... via%3Dihub
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This sounds interesting, I might work on something for this, but I have to say one thing: nuclear ships, with enough power for their entire service life, will most likely not be streamlined or otherwise made super fancy.....
Point taken. I really like the bow on the image I linked. It's... sexy. I'd like to go for a balance; striking... but not excessively fancy. Also, I'm not too familiar with the advantages of different bridge placements, e.g. forward vs. midships vs. aft.

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odysseus1980
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 25th, 2017, 4:16 am
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I am interested to this project, since a shipping company from ny country is involved. Not have knowlegde to help however.


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Tobius
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 25th, 2017, 4:28 am
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Wow. Where do I begin?

1. Engineering wise, there is this:


And where will you recruit a ship's crew to operate a piece of untested highly experimental machinery, that from the descriptions I read, makes a Fukushima reactor (GE light water reactors that some engineers who looked at the upside down lightbulb containment design considered very unsafe) look simple and safe? Be aware that Hyperion and Sandia have been working on that concept since 1998 and it is still not considered man-rated safe.


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Wikipedia & Universe
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 25th, 2017, 1:32 pm
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Tobius wrote: *
Wow. Where do I begin?

1. Engineering wise, there is this:


And where will you recruit a ship's crew to operate a piece of untested highly experimental machinery, that from the descriptions I read, makes a Fukushima reactor (GE light water reactors that some engineers who looked at the upside down lightbulb containment design considered very unsafe) look simple and safe? Be aware that Hyperion and Sandia have been working on that concept since 1998 and it is still not considered man-rated safe.
As someone who plans to go back to school for nuclear engineering and considers himself decently knowledgeable about nuclear energy, I'm well aware of the engineering challenges inherent in any reactor design. I would imagine that the folks designing, building, and deploying everything from PWRs to HTGRs would be taking issues such as corrosion, toxicity, and terrorism into account.

Moreover, there appears to have been a bit of confusion, as I'm not referring to the old self-moderating UH3 design, though I hadn't heard of it before and find it intriguing. Rather, I'm referring to the revised 2009 design for a more conventional lead-bismuth cooled reactor using UN fuel. Mind you, there still hasn't been a working prototype built of this specific design, but it's nowhere near as exotic as the original proposal. We know that LFRs work; the Russians used them in their Lira-class subs, and they performed very well, the K-64 incident notwithstanding.

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Tobius
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 25th, 2017, 8:54 pm
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The Russians? Nuclear reactors? The Russian LFRs are not safe. As I understand it, the LFR was installed in prototype form in Russian Alpha class submarines. Project 705, Лира translated as Lyre. The reason was the Russians needed a lightweight thermionic pile to operate a steam turbine plant that is lighter than the failed LWRs they previously used on their earlier submarines.

The LFR's drawbacks aside from radiation leakage in the faulty tub containment was that the reactor tubs had short life spans (neutron embrittlement about 10-15 years), could not be backfitted with new shells, because the sub would have to be cut in two to pull the whole tub out, and the things had to be run "hot" on standby, because the lead/bismuth eutectic to work has to be a liquid.

123.5 °C. is the floor. The reactor to be happy would have to be closer to 200+°C. This is not water which from steam will condense to liquid at 100 °C and stay that way in a cold reactor *(about 25-40 °C). It is a metallic alloy which will become a useless lump at the bottom of the tub.

In other words an LFR cannot be easily scrammed or shut down cold and restarted, the coolant would solidify in the tub. That little drawback from a ship's power plant point of view is why the USN, which looked at this problem (and apparently has good system engineers) decided that double circulation heat exchanger cycle LWRs were the way to go for a steam turbine propulsion system. It is about four times larger and five times heavier than a BREST, but unlike the Russian harbor queens that can only go to sea as bastion defense boats (That would be the Alfas) the Virginias, Seawolfs, Ohios and Los Angeles boats can stay at sea to blockade and hunt. The Alfas have to stick close to home for a tow into port in case something goes wrong as it has on several occasions when the supposedly free circulation convection system fails in one their sub's reactors.


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Wikipedia & Universe
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 26th, 2017, 3:02 am
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What is your point? I know the pros and cons of LFRs, as do the engineers who design and seek to build them. The sole point of bringing up the Russian example (which is relatively primitive 60s tech and would be far inferior to a 2010s Western design) was that they can work, and that the Gen4 proposal isn't as out-there as the previous UH3 one from the 90s.

So far I haven't seen anything that would compel me to abandon the use of an LFR, just engineering challenges to be overcome in an AU design that hasn't even been drawn yet.

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Kannevets
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 26th, 2017, 12:02 pm
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This sounds like an awesome project and an even more awesome thought experiment. Keep it up!

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Tobius
Post subject: Re: Practical Nuclear Merchant VesselPosted: September 26th, 2017, 6:32 pm
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Wikipedia & Universe wrote: *
What is your point? I know the pros and cons of LFRs, as do the engineers who design and seek to build them. The sole point of bringing up the Russian example (which is relatively primitive 60s tech and would be far inferior to a 2010s Western design) was that they can work, and that the Gen4 proposal isn't as out-there as the previous UH3 one from the 90s.

So far I haven't seen anything that would compel me to abandon the use of an LFR, just engineering challenges to be overcome in an AU design that hasn't even been drawn yet.
If I need to explain my point in further detail, then please PM me. For that discussion would derail this thread. As for the BREST being 1960s tech in the Alfa, then I suggest that this is not the case at all. Perhaps one confuses the Russian 1980s LFR approach with the sodium or other fast breeder reactors under current development or rejected by the US in the past?.


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