It was an experimental design and as the article says, it was very expensive. Titanium was not just expensive, but it was hard to use. Welding had to be done in an inert gas chamber.
Imagine building an inert gas chamber for a submarine.
I think that's a better overall article than the original link.
New reactor design was experimental as well. Lead bismuth mixed had to be kept 120'C or higher. But it was much easier to increase it power momentarily, say if they wanted to chase someone.
There is also a youtube video about it among others:
In one of the videos they mentioned when they did sea trials, the speed got so high it stripped the paint off. It was also fun to show off their new toy to the Americans.
Titanium welding is typically done by purging the air around the weld and/or pumping the inert gas into the parts being welded assuming they're tubes, etc.. A bunch of the gasses involved are heavier than air and that property can be used to come up with clever solutions.
Maybe the Russians built a giant chamber but that seems like a very non-russian solution considering their great awareness of KISS. More likely they found a way to seal an area around the weld and weld in sections that allowed them to pump inert gas into small areas near the welding equipment.
Ah ok. They were showing people putting on what looked like moon suits and going into a chamber. I imagine that's for smaller scale welds. But I imagine pumping argon under pressure to displace oxygen in some areas would work as well. Then ventilate properly as it would settle and well ... suffocate people.
Is that so? I recall the reading a piece on the SR-71 and it mentioned that the titanium was, ironically, sourced from the Soviet Union who supposedly were behind in titanium tech. Further, I remember a following tidbit about one of their jets still being made of steel because of their supposed lagging metallurgical skills. Have they since leapfrogged the US?
If you read the linked articles here it was exactly that attitude that allowed the US to tell itself that it was impossible that the Russians had the capability to make a Titanium sub for about a decade.
This is tangentially related: I came across this Reddit post a while back that I found very insightful. In the area of submarine design, the Soviets/Russians are actually much more innovative than Americans. They seem much more willing to try new ideas whereas Americans stuck to a more conservative try and true design.
That is an interesting post. it relates to the KISS philosophy, which apparently originated in the US military (at least, that name for it).
Also the reformers of the 70s and 80s, the group around John Boyd, Pierre Sprey etc., really pushed for simpler equipment, in opposition to high-tech complexity. It's a recurring theme, and it's definitely a kind of conservatism since it always keeps a (more or less) skilled man in the loop. In a way it creates the conditions for human excellence in the old sense, which automation does away with.
This 2010 book on cultural differences in military innovation may also be relevant:
The Culture of Military Innovation
The Impact of Cultural Factors on the Revolution in Military Affairs in Russia, the US, and Israel.
DIMA ADAMSKY
Early on they rushed poorly designed submarines out with poorly trained crews and poor leadership. There was also a blame culture eg welding rescue bouys to the hull because if they came loose accidentally then the factory would be punished!
These were among the only Lead-bismith cooled nuclear reactors ever operated. Sodium-potassium eutectic or pure sodium coolant is a better heat transfer fluid but in a water environment it's just a little crazy due to sodium-water chemistry. The US Navy tried sodium coolant in the USS Seawolf [1] and it was smaller, quieter, and more powerful, but they had problems with the steam generators. Not an unsolvable problem but definitely a challenge. The success of the water cooled competitor eventually led to the predominance of water cooled reactors in the commercial fleet.
Passively safe Lead-cooled commercial reactors are still thought about today. Challenges include high pumping power required due to high density, erosion issues at high coolant velocity, and corrosion issues without very stringent oxygen control.
> The success of the water cooled competitor eventually led to the predominance of water cooled reactors in the commercial fleet.
By commercial you mean operational (as in non-experimental Navy vessels.) There's precious few commercial nuclear vessels in history (four, each from a different country and I don't think they were ever operational all at the same time), so talking about the dominance of a particular nuclear technology being dominant in a “commercial fleet” seems misplaced.
I meant to refer to the commercial fleet of commercial nuclear power plants making electricity on land, almost all of which have designs directly descended from naval designs. I guess "fleet" isn't a great word to use in the context of naval vessels. Whoops!
Its not commonly known, but the initial generation of commercial power reactors in the US is basically the result of technology transfer from the Naval Nuclear Propulsion program.
I wonder if we'll see non-pwr naval reactors anytime soon. A high temp reactor would allow using a supercritical CO2 Brayton cycle which would take up much less space.
On another note, what would happen if a MSR powered ship would sink and the fuel salt would come into contact with sea water? Would the salts dissolve into the water? Much as I like MSR's as a concept, if so this would make them a quite bad idea on a ship...
The Uranium tetrafluoride itself is basically insoluble in water. But the fuel isn't really the issue, Uranium is a toxic heavy metal but in terms of irradiating the environment outside of a reactor it's not very radioactive at all. People always clamour over Uranium having a half life of billions of years but what that means is that Uranium basically doesn't decay on its own. It's fissile, so hit it with a neutron and you'll induce it to split, but once it leaves a reactor and is subcritical you don't have to worry about the radiation from Uranium.
What you do need to worry about is the radiation from the products of fission as those are the nasty components of nuclear waste. Not only do you have the direct products which have a tiny half life compared to Uranium, those direct products have a decay chain of their own and in most reactor designs out there those products stay in the reactor so not only do you have the decay to contend with, you also have additional fission since it's still being bombarded by neutrons. This is what leads to the toxic soup of radioactive waste, you get tons of isotopes of elements so while the fuel itself wouldn't be too terribly awful for the environment the partially burned fuel is dramatically more radioactive.
The fuel salt itself though if it's anything similar to what was used in the MSRE or FLiBe's new Thorium breeder reactor would actually be insoluble in water and would freeze, hopefully trapping the waste in the frozen salt just like vitrification of nuclear waste. I am not a chemist, and any knowledge I have on the subject is just the result of a hobbyist interest in the subject, but I would think that in the event of a MSR being sunk and breached that the frozen fuel salt would keep most all of the radioactive products dissolved in it safely contained.
MSRs use either Th/U-FLiBe or U/Pu-NaCl and both of those would easily dissolve in water. But honestly radioactive inventory of these cores is small enough that one or two breached systems, while catastrophic, wouldn't have significant biological consequences as it disperses in the vast oceans. Certainly this wouldn't be acceptable for civilian operations but I wouldn't put it past an ambitious military. Problem with Molten Salt in a submarine is size. The fuel salt is very low density compared to metallic nuclear fuels, by about an order of magnitude. That would require more volume to be critical. Small thermal/epithermal solid fueled reactor cooled with water, liquid metal, or even solid fuel/salt cooled reactors (like the FHR) are appropriate for submarines but probably not full-on liquid-fueled MSRs.
Not in the US Navy. Part of the reason the US Navy standardized on PWR is that while it's not the most efficient it is something you can restart at depth if necessary. The lesson of how much that matters was driven home by the loss of the USS Thresher.
It should be technically feasible to restart a liquid-metal cooled reactor at depth just as easily as a PWR, especially a Na- or NaK-cooled one. Certainly keeping the coolant liquid after shutdown can be a challenge but as long as the plant has operated for a while there should be significant decay heat to keep it warm, and trace heating in the pipes could be powered by auxiliary power if necessary.
The kind of emergency restart procedure employed today would work just fine on a MSR design. We're talking restarts on the order 1-10 minutes after an emergency shutdown. That's not nearly enough time to solidify the core, even when you are drawing some steam for emergency propulsion needs while the reactor is shutdown.
The USN has, to a material degree, perfected the compact PWR.
Their experience in fuel design, materials, cooling, support systems, control systems, and processes pose an enormous barrier to new systems other than those that could truly radically simplify the reactor system and yield a huge gain in reduced manpower and increased reliability.
I think the best marginal gains are coming and will come from developments in tactical and ISR systems.
Zolotaya Rybka was a name these got to be known by as it was an example of what went wrong in Soviet ship building. Basically the story as I understand it is that they ordered ships based on capability and not their cost which led to an exaggerated military budget versus GDP. Combined with Oscar and Typhoon ships they simply ran themselves out of money.
however they were the pride of a Soviet navy that knew they could not afford the carriers and support ships the US had but were convinced when push came to shove the submarines would be more than up to the task.
Here's a tiny bit of explanation second hand from USN about why the USN does not use them - too much chance for things to go wrong, although that's not surprisng they would say that considering that's what the Soviets said happened on the sunken submarine being discussed.
https://www.nytimes.com/1989/05/04/world/rescue-capsule-save...
On the flip side between where you can get out in a survival suit, where rescue submarines can get to, and places where the people tank will go crunch before you hit the bottom, pretty much everything is covered for USN submarines; it's a very safety conscious community.
It's a pelican static site but in git; then there is a tiny Python webserver that 'publishes' the bare git repo, not unlike a custom github pages.
And it's running on an absolute-cheapest VPS with no RAM or CPU to speak of.
The good thing about the host though is they limit bandwidth rather than total bytes, so sure it slows down - it's really being hammered right now! - but it won't die with a nasty message when it hits some total-bytes-per-month limit.
Fun fact - as I was reading Red October, I got a job as an electronics apprentice/tech at the yard in Portsmouth NH, and the first boat I stepped onto was the Dallas. Was a cool moment.
"Max depth" is kind of a nebulous concept though. There's the "test depth" which is as deep as they're willing to test the submarine. There's the maximum operational depth, which is some lesser depth that keeps a safety margin over the test depth. Then there's the "crush depth", which is the depth at which the submarine will actually fail, and is hopefully substantially deeper than the test depth.
Been a while since I've watched "Das Boot", but IIRC, there's a scene in the movie where, initially on the surface, they have a taught string strung across the sub. Then, as they dive, deeper and deeper, the taught string relaxes giving a rather frightening visual insight into how much the hull of the boat is compressing.
Imagine building an inert gas chamber for a submarine.
More info about it here https://foxtrotalpha.jalopnik.com/russias-alfa-class-was-the...
I think that's a better overall article than the original link.
New reactor design was experimental as well. Lead bismuth mixed had to be kept 120'C or higher. But it was much easier to increase it power momentarily, say if they wanted to chase someone.
There is also a youtube video about it among others:
https://www.youtube.com/watch?v=IJ34mE-aCdY (in Russian though)
https://www.youtube.com/watch?v=lO6FZ_ztzKM
In one of the videos they mentioned when they did sea trials, the speed got so high it stripped the paint off. It was also fun to show off their new toy to the Americans.