Nuclear reactors and pollution

This may have been discussed before, apologies if it has. Though I wanted to know: what happens if a nuclear sub goes down near a coastline? Let's say 200 miles off the coast of an inhabited coastal town/beach resort and say 500 metre depth? Would the radioactive slick be lethal? And at what range?
Would the salty sea water combined with the pressure be enough to subdue any real pollution?

Must've been quite a dillema trying to stop Soviet boomers reaching American shoreline in the Cold War. Or was it? :hmm:

[Molon Labe]

I think all the nuclear fuel tends to clump together and is heavier than water, so unless something happened to the reactor itself, the impact to the environment of a sub going down should be minimal.

The US does periodic environmental studies in the areas where Thresher and Scorpon went down, and haven't discovered anything "bad" yet.

I was about to make the thread about how unrealistic it was getting orders to take out a nuc near the shoreline...so that's actually very good to know. Thanks.

p.s. Sorry about the orly owl...I've always wanted to use it...at least once.

[Kapitan]

Submarine komsomolets has been at the bottom for 17 years and no radiation leakage she sits near the norwiegen coast.

K8 sank near the western approaches 1970 no reported issues.

The nuclear fuel would have to melt down to make any form of contamination, even then it wouldnt be muchnothing like chernobyl fall out because the melted core would cool in the sea water a bit like a volcanos lava.

Also the fuel is house ina submarine that has a sealed compartment that also has a water and air tight reactor so whats the odds ?

[Henson]

The 'runaway reactor' scenario that we all read about in Clancy's book is supposedly impossible in US boats. I can't speak for russian, indian, or french reactors, but the US reactors 'default' to shutdown state. They basically have to be forced into a critical state ('critical' in this case simply means running, not emergency).

I could be wrong, but that's what the nucs told me during ship's quals. Any nucs here to elaborate?

[Kapitan]

Should a certain amount of trip switches be tripped the russian reactors are designed to shut down by them selves in some cases rods have been wound down by hand but its normaly nessasery.

During an emergency fire or what should the crew need to shut down there reactor there are switches in all compartments.

[TLAM Strike]

I think they are going to build a big cement tomb over the Komsomolets or K8 at some point rather than risk contaminating the rich fishing zones near where they sank.

[Bubblehead Nuke]

How to discuss this, and not break any rules.....

Okay, the control rods, when de-engergized, revert automatically to a fully inserted position. This is ALL the control rods, not just the SCRAM group. There is sufficient nutron attentation to adequately ensure a core shutdown even if one or 2 where to 'stick' at some position not corrosponding to full insertion.

The reactor vessel is probably the single strongest component on the submarine. In a hull collapse the primary cooling lines will, in all proabability, be severed from the contaiment vessel. This will make the vessel non-collapsable as internal pressure will be equal to sea pressure. This is important for as long as the containment vessel is intact the control rods will be maintained in the proper configuration to ensure continued core shutdown.

The worry then is corrosion of the fuel matrix and the subsequent release of radioacive material. Again, as long as the containment vessel is intact this should not result in the significant spread of contamination as any corrosion products should be maintained inside the containment vessel.

The corrosion of the containment vessel, due to the nature of the materials used, will be very slow. If the vessel lays at a considerable depth the corrosion rate will be further reduced by the low free-radical and oxygen content of the seawater at extreme depths. If it is in shallow water where corrosion can be a significant factor then means can be made to bring the containment vessel to the surface. Remember, we once dang near raised a Golf class sub many years ago. The reactor vessel is significantly smaller and lighter than a sub

With that being said here is another thought track.

If the submarine in question were to be damaged, say by a torpedo, and the reactor vessel is ruputed distupting the control rod configuration. Well, that would be bad. With no control rods the reactor would pretty much be uncontrolled and the resulting fission products would be scattered to the seas and currents. We are talking Chernobyl of the seas here. Massive contamination on the order of months and years. On the bright side, that is an absolute worse case. It would be an incredible lucky (unlucky??) explosion that would disrupt the control rod configuration and NOT disrupt the core configuration so much that criticality could be maintained on any small scale, let alone a scale large to make significant measurable contamination.

[Bubblehead Nuke]

Originally Posted by Kapitan

During an emergency fire or what should the crew need to shut down there reactor there are switches in all compartments.

My GOD. What an incredibly stupid design . One man, who did not know the true extent of a causality, could shut the reactor down, limiting propulsion, electricity, manuverabilty. I can think of a dozon causualties off hand were shutting down a reactor would take it from the managable to possible, if not certain, Loss of Ship.

Sorry for the caps but I know any ex nuke submariner just got the shakes READING that

[Kapitan]

The russian reactors are nothing like the american ones, there has been reactor shut downs in the past but its a safty feature in the reactor to stop anything bad happening. not sure if its implemented in the new builds but it is in submarines like the Victor III Akula's oscars deltas and phoons.



And here is the nuclear reactor of a typhoon class SSBN reactor designated 0K-650B pressureised water cooled.

[Henson]

Once again....my GOD.

Wow...I'm in awe at you guys amd your knowledge (and slightly jealous!).

Though as Bubblehead Nuke said, if there is a danger there could be pollution if the sub is torn apart in an explosion...do they design torps so it doesn't destroy the sub but just damages it enough to make it sink?

...also related...has anyone ever seen a photo of a nuclear torpedo exploding underwater? Would love to see one...or it's effects on the surface.

[TLAM Strike]

Originally Posted by Kurushio

...also related...has anyone ever seen a photo of a nuclear torpedo exploding underwater? Would love to see one...or it's effects on the surface.

Well this is a nuclear depthcharge deployed from an ASROC.
Test "Sword Fish"

Note the ship in the image was used to test how much it would be affected by the blast, it was unharmed.

I don't think the US ever test detonated the ASTOR. For a torpedo the only thing I could think of would be a Russian test and the odds of finding an image of that are quite low.

[Sub Sailor]

I guess it is possible a torpedo could crack or possible break the Reactor Vessel, but most unlikely. The vessel itself is a huge chunk of metal and it is further contained in the shield water tank.
It is without a doubt the single strongest component on the boat. The designed safety factors in US Reactors are actually way overkill. Scorpion and Thresher's vessels are still intact. I don't even know how long before they would leak fuel.
US Reactor Compartments are sealed and locked at all times, except in an emergency. In the old days we used to discharge resin beds before entering the ship yard, but not anymore. That is the only time I ever entered the Factor Compartment at sea. Of course the plant was shut down.
The control rods, as BH explained fail safe, and the plant was designed with stuck rod(s) planned in. I never encountered a stuck rod. Supposedly we could operate with (some) number of rods stuck out.

Ron Banks MMCM(SS), USN(Ret)
a really old nuke, 1962-1981. All Subs

[Sub Sailor]

Reactor Compartment.

Sub Sailor