True, but it also represents a single point of failure. You have your inland nuclear reactor and a whopping great pipe leading from the coast. Then you have a force 9 quake. How strong would the pipe have to be to withstand that? Pretty bloody strong. The whole prefecture has lost gas and water supplies, so it sounds like pretty much no trunk pipe survived intact. GPS systems suggest the whole of Japan has actually moved a few feet west. A whole country. Say the pipe fails. Now, instead of a power plant near the coast with a ready emergency water supply, albeit one you don't want to use unless you have to, you've got a power plant miles from the coast with only whatever water you have to hand and no way to replenish that at the rate you require.
What you would actually need is a plant somewhere with two - or possibly even three - pipes from different water sources which you can fall back through in the event of a loss of service. If you're 100 yards from the sea, you can get a new pipe/pump system up and running pretty quickly in a disaster situation - apparently they used the local fire brigade systems, which is something given there was an oil refinery ablaze not that far down the road... If you're 50 miles from the sea, you're stuffed. You need a standing body of water that's accessible within, well, minutes.


Yep, the ideal location is probably somewhere fairly remote next to a very large body of water - say a lake or reservoir. I doubt Japan has anywhere they could really do that though.

Jon

There are relatively few uranium mines in the world so the raw material would come by sea chances are, but refueling is not the major requirement - a nuclear reactor doesn't get refueled that often. The problem is much more getting the waste (which is much more radioactive than the fuel you started with) away. I don't know if you've ever seen the footage of them testing the vessels they put the waste in, but they're pretty tough. The test I saw had them run a BR diesel train into one at full pelt. The train took a beating but the vessel wasn't breached. I believe the French also test-fired an anti-tank rocket at one of theirs and it survived intact.


Actually, traditionally, populations tend to live on the coast, because large cities have tended to evolve where it was easiest to travel and trade and that was pretty much all done by sea or river, so the logical place to put your house is where a river meets the sea.


I think at this point you have to assume the people building nuclear reactors have spent a long time thinking about where to put them and how to protect them and us lot trying to second guess them isn't likely to come to anything conclusive... .

I come back to the basic point though - Fukushiima has suffered a force 9 earthquake, a 10m tidal wave and multiple backup systems fail and still has had (so far, touch wood) no reactor vessel failure as far as I know. I don't really see what more you could ask for, to be honest.

Jon

Quite.

It's best to omit unnecessary variables.

Eastern seaboard of the US?

It's a BWR so there has to be a steam dryer at the top of the reactor and the control rods inserted from the bottom. This isn't a problem though - the hydraulic systems are pretty much failsafe.

Furthermore the control were inserted as soon as the earthquake happened to shut down the reactors. It was the tsunami buggering up the coolant pumps that's fecked everything. The artificial fission has been stopped but the rods are still producing heat from natural radioactive decay.


Remember though that this was a once in a millenium event. If the tsunami had been even just a bit smaller this problem wouldn't even have arisen.

However the newer ABWR designs have the pumps much higher up so any new station wouldn't be vulnerable.


Possibly the Great Wave of 1607 but that's currently disputed

Very true.

I'm sure they are a lot more qualified than all of us put together (times a thousand) when it comes to placing, designing and building nuclear power stations.

I don't get. They're due a massive quake/tsunami too in the future.

Edit: Western....

I may just go back to bed.

True I am not claiming to be any great expert (at anything) though would have thought that the back up generators would have been given even greater protection as the main reactors as they seem to have been the weak link. May be if they had been up a hill then they would have escaped the tsunami altogether and all that might have needed replacing was the power line. Which is relatively simpler than what they are experiencing now.

Even so sometimes the final decision is made by a politician with alternative agendas, like job creation etc.

Any system will have a weakest link, even though it in fact may not be that weak. I don't think you can make diesel generators waterproof though - you'll always need an exhaust pipe the water can over-run.


Yep, although the generators would need to be bigger because you'd lose power over the longer power lines. And therefore you'd need more fuel in place, or they'd have a shorter lifespan in operation. All things that need to be balanced. What you want to avoid is having a power station on standby in case your power station has problem .

I suspect in the near future we won't be using fossil fuel power sources for these kinds of things anyway - fuel cells for example would be much better, at least once we've figured out how to store hydrogen efficiently & safely...


In this case yes; either that or have a stockpile of replacement batteries - remember the battery power in the first backup was used up before the diesel generators had to kick in - which you could charge up from a surviving power source then rotate into place to keep the coolant flowing with the generators only in use when the batteries are being swapped; a kind of son - father - grandfather system. Although who knows what would have happened to the batteries if they'd have had any juice left when the tsunami hit...

Jon

Even though this was a once in a lifetime event there should have been some thought taken to prevent just such a problem.

There was some thought given to prevent just such a problem.

Firstly the BWR pumps have N-2 redundancy. This means that a once in a century accident can knock out two of the four pumps and the reactor level will be fine. For comparison, a once in a lifetime event wouldn't be expected to trouble the facility at all. However, this wasn't a once in a lifetime event - it was a once in a millennium event. The last time a comparable wave hit this part of the coast was in 896AD. Despite such a massive event, one pump kept working.

Even if the last had failed and all three reactors gone to meltdown, the design of the reactors means that the bulk of the problem would be very localised i.e. hundreds of meters rather than Chornobyl's tens of miles. Chornobyl had a large graphite fire that carried the fallout high into the atmosphere and an RBMK design that didn't feature any containment. Fukushima contains no graphite and does have a very good containment system.

It really isn't the cataclysm it's being portrayed as.

It is a game of balancing risk with cost.

What is the chance of it being hit by an earthquake the likes of which we haven't seen for over 1000 years? And what is the cost associated with ensuring that if hit by that the plant will remain in tact?

If they had protected against a factor 9.0 earthquake and tsunami but instead it had been hit by a 5m diameter meteor? Would they then be able to say they had done enough to protect the plant or would people still say they hadn't taken enough precaution?

Point of fact : It has remained intact. Apart from some fairly spectacular but as far as I know only cosmetically damaging explosions, the plant itself has withstood everything that was thrown at it. Ironically, the systems that failed are the ones that were only ever going to be activated in an emergency, but the main system itself has coped much better than they have.


If the plant had taken a direct hit by a 5M diameter meteor, I doubt there'd be anyone left alive inside the possible contamination radius to care anyway. A 5M wide lump of metal hitting the ground from far orbit contains an absolutely ludicrous amount of energy. You might as well ask what would happen if it was hit by a groundburst ICBM warhead.

Jon