8.9 earthquake Sendai, Honshu, Japan _Tsunami

[bwilson4web]

Perhaps they need heliocopter liftable, generators with sufficient power to handle emergency power needed for "n" power plants. When not applied to the power plants, use them as "topping" systems elsewhere in the grid.

Bob Wilson

[euromodder]

Hindsight is always 20/20 , but still.

Looking at the reactor design schematics and given that the rods absolutely need cooling, why on earth did they ever put them at the top of the vessel with the cooling water collecting on the bottom ?

If it was convenience then they're paying one hell of a price for that convenience !



That's simply not fail-safe, it requires pumping just to keep any sort of cooling going.
Putting the cores where even the last remaining water will naturally pool at least gives the emergency option to evacuate a lot of heat by making and venting steam.
Putting the reactor underground and using a simple water column design, it could even have been slightly pressurized by simply pouring on water.

Additionally, any leak below the cores - which now means most of the cooling system - will drain the coolant away from the cores.
So having less of the cooling system below the cores can reduce the chance of that happening.


If I had been asked to design that, I'd basically have inverted it.
Reactor low, coolant above it.
Even with total pump failure, it could have been designed to resort to natural convection flow.

[roflwaffle]

Originally Posted by bwilson4web

Perhaps they need heliocopter liftable, generators with sufficient power to handle emergency power needed for "n" power plants. When not applied to the power plants, use them as "topping" systems elsewhere in the grid.

Bob Wilson

RC would be nice too, in case there was already a dangerous release of radioactive material.

[cfg83]

bwilson4web -

Originally Posted by bwilson4web

Perhaps they need heliocopter liftable, generators with sufficient power to handle emergency power needed for "n" power plants. When not applied to the power plants, use them as "topping" systems elsewhere in the grid.

Bob Wilson

Yeah, I said that earlier :

http://ecomodder.com/forum/225478-post29.html

3 - They did transport new power generators into the site, but I don't know if this was part of an existing Plan-B or just improvisation. You could have heavy lift choppers for generators and diesel fuel on standby for just this scenario. The only requirement would be a high-ground heliport (aka tsunami-proof) that could get the generators and diesel-fuel to the reactor *and* installed before the backup batteries went dead. This does not address the possibility that the helicopters and/or backup-backup generators would *also* be damaged in the initial earthquake.

However, the power attachments were *also* in the basement. You'd have to design the building to have multiple locations for power input. You'd need top and side connections. It would have to be "wired for power".

CarloSW2

[cfg83]

euromodder -

I think the current generation designs take your questions into account.

BWR = Boiling water reactor - Wikipedia, the free encyclopedia = Fukushima
ABWR = Advanced boiling water reactor - Wikipedia, the free encyclopedia
ESBWR = Economic Simplified Boiling Water Reactor - Wikipedia, the free encyclopedia

The ESBWR uses natural circulation with no recirculation pumps or their associated piping, thereby greatly increasing design integrity and reducing overall costs.
The passively safe characteristics are mainly based on isolation condensers, which are heat exchangers that take steam from the vessel (isolation condensers, IC) or the containment (passive containment cooling system, PCCS), condense the steam, transfer the heat to a water pool, and introduce the water into the vessel again.
This is also based on the gravity driven cooling system (GDCS), which are pools above the vessel. When very low water level is detected in the reactor, the depressurization system opens several very large valves to reduce vessel pressure and finally to allow these GDCS pools to re-flood the vessel.
All of the safety systems operate without using pumps, thereby further increasing design safety reliability and reducing costs.

http://www.nuclear.gov/np2010/pdfs/esbwrOverview.pdf




CarloSW2

[gone-ot]

...what happened to good old, tried-n-true, thermo-syphoning, ala' old automotive radiator systems (augmented by pumps)?

[bwilson4web]

The ocean currents from Japan head towards the Bering Sea and Alaska. This is where we get snow and king crabs and huge hauls of fish . . . excellent radiation concentrators.

Bob Wilson

[euromodder]

Originally Posted by bwilson4web

The ocean currents from Japan head towards the Bering Sea and Alaska. This is where we get snow and king crabs and huge hauls of fish . . . excellent radiation concentrators.

Deadliest Catch indeed !

[euromodder]

Originally Posted by Old Tele man

...what happened to good old, tried-n-true, thermo-syphoning, ala' old automotive radiator systems (augmented by pumps)?

Don't worry, it's still used in the chemical industry, so it hasn't been forgotten

[Piwoslaw]

A few days ago there was a program on Polish TV about how safe nuclear power is. The reporters acted as if they didn't know that Fukushima has been smoking for at least 2 weeks. And as if they didn't remember that Chernobyl was 500km away.