What could possibly go wrong ?

Minusorange · 2 Jul 2019 at 19:56

https://www.rt.com/business/463129-russia-arctic-nuclear-power/

The world’s first floating nuclear power plant (NPP), built by Russia and called the ‘Akademik Lomonosov,’ has received a license for operation. It is to provide heat and energy to Russia’s remote regions in the Arctic.
According to Rosenergoatom, at the end of August the vessel will be towed to Pevek, a port city on the Arctic coast of the Chukotka region. It will thus become the northernmost operating nuclear plant in the world.

At least if it sinks, the reactor fuel will have a constant supply of cooling water, so I guess there's that

And I guess the tech is somewhat proven by nuclear powered ships and submarines, but it seems at first glance a silly idea to go from a nuclear reactor that powers a ship, to having a reactor on a ship that powers a city, considering all the disasters we've had in the 70 years of playing with nuclear energy and still not really having a suitable method to dispose of the waste beyond storing it and no real solution to quickly fixing things when it goes terribly wrong like Chernobyl and Fukushima

Malevolence · 2 Jul 2019 at 20:03

Not trying to be pedantic here, well just a bit, but isn't any nuclear powered ship/boat basically a floating nuclear power station?

Minusorange · 2 Jul 2019 at 21:36

According to wiki

Current U.S. naval reactors are all pressurized water reactors, which are identical to PWR commercial reactors producing electricity, except that:

They have a high power density in a small volume and run either on low-enriched uranium (as do some French and Chinese submarines) or on highly enriched uranium (>20% U-235, current U.S. submarines use fuel enriched to at least 93%)[3]

They have long core lives, so that refueling is needed only after 10 or more years, and new cores are designed to last 25 years in carriers and 10–33 years in submarines,

The design enables a compact pressure vessel while maintaining safety.[clarification needed]

Long core life is enabled by high uranium enrichment and by incorporating a "burnable neutron poison", which is progressively depleted as non-burnable poisons like fission products and actinides accumulate. The loss of burnable poison counterbalances the creation of non-burnable poisons and result in stable long term fuel efficiency.

Long-term integrity of the compact reactor pressure vessel is maintained by providing an internal neutron shield. (This is in contrast to early Soviet civil PWR designs where embrittlement occurs due to neutron bombardment of a very narrow pressure vessel.)

Reactor sizes range up to ~500 MWt (about 165 MWe) in the larger submarines and surface ships. The French Rubis-class submarines have a 48 MW reactor that needs no refueling for 30 years.

Seems they're smaller and safer and require less maintenance than an actual nuclear reactor powering entire cities

Diddums · 2 Jul 2019 at 22:04

Well if it goes **** hopefully Sky will make a docudrama about it.

Jumper118 · 2 Jul 2019 at 23:21

Malevolence said:
Not trying to be pedantic here, well just a bit, but isn't any nuclear powered ship/boat basically a floating nuclear power station?

this. at least if it melts down it will break down those micro plastics in the the sea quicker so the the green crowd will be pleased.

Terminal_Boy · 2 Jul 2019 at 23:25

The Russians will do what they always do with old reactors from their nuclear submarines and dump them in Swedish waters at night.

Angilion · 3 Jul 2019 at 00:11

Malevolence said:
Not trying to be pedantic here, well just a bit, but isn't any nuclear powered ship/boat basically a floating nuclear power station?

Generally a great deal smaller and much lower power output, which can matter. For example, one of the causes of the Three Mile Island meltdown resulted from the training that that the people operating the reactor had been given, which was on nuclear powered ships. The key thing on a ship's reactor was the pressure in a particular part of the reactor's pressurised water/steam system. If the reactor had shut down, that pressure was the thing that mattered. It mattered more than cooling the core when the reactor had been shut down. True on a nuclear powered boat. Absolutely not true in a nuclear power station. It's the opposite in a nuclear power station. The reason is decay heat. When a fission reactor core is shut down, fission stops but heat is still generated by radioactive decay of the fuel. In a ship's reactor, it's KW of heat. You can leave it for a while with inadequate cooling, not a big problem. In a nuclear power station, it's MW of heat. Leave that with inadequate cooling and you're having a meltdown very soon.

Incidentally, the fix for not having things go wrong like Chernobyl and Fukushima Daiichi is to not use obsolete reactors (both), not use inherently unstable and dangerous reactor designs (Chernobyl), not run them incorrectly with safety equipment disabled and without properly trained personnel (Chernobyl), not cut costs on protecting them from things that might happen (Fukushima) and have a backup plan that will work in predictable adverse circumstances (Fukushima).

Efour · 3 Jul 2019 at 06:53

SeEmS slightly relevant.

Terminal_Boy · 3 Jul 2019 at 07:31

Angilion said:
Incidentally, the fix for not having things go wrong like Chernobyl and Fukushima Daiichi is to not use obsolete reactors (both), not use inherently unstable and dangerous reactor designs (Chernobyl), not run them incorrectly with safety equipment disabled and without properly trained personnel (Chernobyl), not cut costs on protecting them from things that might happen (Fukushima) and have a backup plan that will work in predictable adverse circumstances (Fukushima).

So, basically, the fix is not to do all the things that Russians always do with nuclear reactors. I’m already seeing a potential problem having the same Russians build and operate these new floating power stations.

robj20 · 3 Jul 2019 at 07:35

Seems a logical place to build it, something goes wrong sink it. From the basics i know water is the thing you want ample supply off.

Minusorange · 3 Jul 2019 at 12:33

robj20 said:
Seems a logical place to build it, something goes wrong sink it. From the basics i know water is the thing you want ample supply off.

After doing some further research, it seems sea water is something you don't really want going near to a reactor unless absolutely necessary like at Fukushima where they had no choice

Werewolf · 3 Jul 2019 at 12:37

The idea of a Russian floating nuclear reactor is slightly scary, even if it's based on the ones they use on their subs - from memory Russia does not have a great history with it's ship board nuclear reactors.

robj20 · 3 Jul 2019 at 12:40

Minusorange said:
After doing some further research, it seems sea water is something you don't really want going near to a reactor unless absolutely necessary like at Fukushima where they had no choice

Not sure why, Wylfa was seawater cooled, im sure they are even proposing building a new one there.

Minusorange · 3 Jul 2019 at 12:53

robj20 said:
Not sure why, Wylfa was seawater cooled, im sure they are even proposing building a new one there.

The sea water was/is used to cool the steam condensers not the actual reactor

You don't want sea water coming into contact with a reactor because it's corrosive

Why does a nuclear facility normally rely on purified water to cool its reactors? How is it purified?
I'll give you an example: If you have a boiling pot and your water has too many minerals, then condensation will collect inside your boiling pot. When this happens in a reactor, it interrupts the properties of the fuel elements. Energy companies don't want to jeopardize the performance of their reactor materials, so they use purified water, usually from a special water purification plant on site. Purifying the water removes most of the salts and anything that could accumulate on the fuel elements.

Under what circumstances would a nuclear power plant use seawater to cool its reactors?
Using unpurified water is not a normal practice—it's never done. Plants don't take water from the river or the sea to supplement their own internal water, which is in completely closed-loop systems. Of course, they take in some amount of new water periodically to make up for evaporation and other losses like that, but this water is purified before it is used.

TEPCO's reactors lost the water below the normal operating condition, so they had to provide additional water for that. Salt-water obviously has a lot of minerals in it, and if it's taken directly from the sea, it has all sorts of other materials floating in it as well. Even if these things were filtered out, the chemistry of salt-water is not really compatible with what normally goes through the reactor. It's too corrosive for fuel elements. I would guess that after this water was introduced into the reactor cores, those cores would become completely unusable. This is because any materials in the water will attach to the surface of the fuel rods and make heat transfer unpredictable.

https://www.scientificamerican.com/article/japan-earthquake-tsunami-nuclear-seawater/

Angilion · 3 Jul 2019 at 22:52

Terminal_Boy said:
So, basically, the fix is not to do all the things that Russians always do with nuclear reactors. I’m already seeing a potential problem having the same Russians build and operate these new floating power stations.

Er...yes. You have a strong point there.

Angilion · 3 Jul 2019 at 23:06

robj20 said:
Not sure why, Wylfa was seawater cooled, im sure they are even proposing building a new one there.

There are often (usually? always?) two completely seperate water systems in a nuclear power station. One loop is heated by the reactor, the other loop is turned into steam used to drive a turbine to generate electricity and then cooled. So while you really wouldn't want seawater in the first loop, you could have it in the second loop, which is the cooling loop. So you could use seawater to cool the reactor indirectly. The two loops should never mix and the second loop should never connect to the reactor. In essence, the water that's heated by the reactor is a way to transfer the heat generated by the reactor to a seperate lot of water.

There's a clear image of the basic setup here:

https://www.chegg.com/homework-help...r-plant-primary-loop-needs-high-pre-q29000160