Japanese Reactor Pumps: Question

[AZRedhawk44]

http://www.foxnews.com/world/2011/03/16/japans-uncertain-following-radiation-level-panic/

So, the power's been out to these reactor pumps for awhile.  I understand they are grid-tied with limited backup power available, and when the grid goes offline, the power from the nuke plant is not self-generating or self-sustaining.

So, the pumps are off.

I am curious what the typical amperage output of these backup generators are?

I understand that in the US, our fire engines in most areas are able to generate pretty significant amounts of AC power.

Even if in the tsunami-affected area the entire engine force is gone... there must be some sort of portable generating capacity somewhere in Japan that the Japanese Defense Force or a civil emergency system can airlift alongside the pump housing and wire up.

How much juice do these pumps need, to operate?

[cassandra and sara's daddy]

9000 horse power pumps?  thats gotta dim the lights

[AJ Dual]

PWR coolant pumps are up to like 6000-10,000hp.

It's a LOT of wattage. The backup diesels are probably like the size of medium cargo ship engines. You're talking like Six Megawatts of capacity.

[AZRedhawk44]

9000 horse power pumps?  thats gotta dim the lights

What's 9000 HP in Amps?

[AJ Dual]

What's 9000 HP in Amps?

Uhh.. six million amps at 1 volt.  

Or at 240V 25000 amps.

Or at 440V 13636 amps.

(9000hp = roughly 6.somethingsomething Megawatts and a Watt = V x A )

[dogmush]

I understand that in the US, our fire engines in most areas are able to generate pretty significant amounts of AC power.

Not really.  Not by industrial standards.

One of the boats I work on has a high volume fire pump on it. Not real big by pumping standards.  450GPM.  It takes a 500HP diesel to run it.  I can close to max out one of our 350KW Gensets with three seawater pumps at full flow.  Thats about 200GPM.  I would imagine the pumps needed to cool a reactor are in the industrial large category. Multiple thousands of GPM, per reactor.  That's a lot of pumping.

I would bet, ballpark guess, that they were running 5MW back-up generators.  So think am engine 15-20 feet tall and 40 or so feet long that haas to be trucked in in pieces and built on site.

I am curious though what happened to the onsite gensets that wasn't so bad they could run for a couple hours, but was bad enough that they haven't been fixed yet.

Unless one of the explosions took them out.

[AJ Dual]

I'm wondering if there was seawater contamination in the lubricating oil from the tsunami, which can cause it to gel, and create massive galling, they got them turned over, but they seized up later.

Or maybe some of the fuel tanks were damaged in the tsunami and they ran out.

I'd think that the backup diesels were placed on the power plant grounds so that any reasonable explosion of a reactor building would not take them out, as a basic precaution.

Or if the coolant lines were crushed, stuck, or blocked by meltdown or reactor debris, perhaps they've ruined the pumps out of desperation, trying to force water in no matter what.

[Nick1911]

I've wondered this myself.

These generators must be massively trashed to not have airlifted in parts and people to get them up again.

But yea, 6mw isn't a small amount of juice.

[AZRedhawk44]

(9000hp = roughly 6.somethingsomething Megawatts and a Watt = V x A )

OK, that's pretty big.  Nevermind.

You need a power plant in its own right just to cool the system.  

I know a nuke plant can generate about a GW per core typically, so it's less than 1% of operating power to cool a nuke plant... but once off grid that's some SERIOUS liability to have to fix quickly within a critical time window.

[AJ Dual]

Honestly the plants did very well in the earthquake, they were only designed for a 7.0, and survived a 9.0 without catastrophe. It was the tsunami and loss of outside grid-power and backup power that did them in. 

[Nick1911]

Aren't aircraft carriers electrically propelled?

Wonder if it would be completely unfeasible to airlift in a beefy transformer and wire up a ship.

[erictank]

Aren't aircraft carriers electrically propelled?

Not yet.  Big-ol' nuclear-driven steam turbines.

Our backup diesels at North Anna were something like 3-4 MW each, IIRC.  Been a while since I looked at the data plates, obviously.

[AJ Dual]

Aren't aircraft carriers electrically propelled?

Wonder if it would be completely unfeasible to airlift in a beefy transformer and wire up a ship.

Actually, they do have a pretty big generating capacity too. Docking a nuclear aircraft carrier to supply a region with supplemental electrical power, and desalinate ocean water during disasters is something we've done before.

However, I don't think we're bringing ANY of our larger strategic assets anywhere near/downwind of these reactors right now.

[drewtam]

I have to imagine that pumps of that size/power are mechanically driven from the industrial engine. In such a case, a combination of tsunami and hydrogen explosions may have wiped out the equipment and piping. They may be welding the stuff back together as we speak.

[KD5NRH]

IIRC, the major problem was that the tsnuami washed a bunch of crap into the cooling water ponds, which clogged the pumps.  Most likely, they burned out trying to suck whatever debris was there through the screens and filters.

[Headless Thompson Gunner]

As I understand it, they lost a lot more than the diesel backups.  There's a substantial infrastructure to make those pumps work, including power distribution and control, fuel, piping for the coolant water, cooling systems for the coolant water, storage tanks, on and on.  ALL of that stuff was trashed, not just the diesel generators.  

Even if you had a spare 6MW power source in your back pocket, you still wouldn't be able to run the primary cooling systems.