Comment by CoryOndrejka
8 hours ago
I don't know this plant. In navy submarine reactors like the S5W, you have 440V/3-phase power holding the clamp. If you dropped a rod due to a power or clamp malfunction, usually you'd simply shut down the reactor, drop all the rods and mechanically re-engage the clamp. It could take a few hours which isn't fun because no power which probably means submarine/snorkel depth to run the incredibly noisy diesel, but no step was particularly hard or dangerous.
Now I’m curious. What if it occurs when you’re like under the enemy and you can’t surface? Do you have to just chill at depth until you can get the reactor running again?
The ship can operate for a bit on decay heat. And they have battery banks to run major systems until conditions allow running at snorkel depth on the diesel engine.
And rumor has it some of the nuclear subs may work with a Stirling engine which can operate systems on heat alone.
The small sub world is going toward AIP. I wouldn't be surprised if the big ones have AIP for emergency power.
2 replies →
I'd imagine the operational capabilities of nuclear submarines are somewhat confidential.
Warships have a “battle short” on some critical equipment, which will bypass safety equipment like fuses. If your gun turret traversal motors pull too much current in the middle of a battle, you’d rather risk damage or fire to have them keep working rather than disable themselves to protect from a fault. Total speculation here, but it would make sense for military reactors to have something similar, to put them in a mode where the threat of a reactor accident due to a malfunction is less than the threat from the enemy if it goes down. https://en.wikipedia.org/wiki/Battleshort
I’ve never been in the Navy or on a submarine, but my impression is that SUBSAFE is about never ever having a reactor accident, at least partially for PR reasons. It wouldn’t surprise me if there simply are not procedures to deliberately put the reactor in a dangerous state.
The Navy may have done the math and determined the loss of a boat to the enemy is a less bad thing than the loss of a boat to a “nuclear accident”.
I desperately hope for and welcome anyone with experience in the space to correct me.
Likewise commercial aircraft have bypasses on the fuel and oil filters in case they get clogged in flight. The engine will need a thorough inspection if this happens but it's better to damage the engine if it gets you to the nearest airfield.
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