BIG Nuclear Trouble - All Reactors Exploded

That area in the north east has the lowest population density, hence why they're there. They cant be built in land as the terrain is quite mountainous. Although there are several nuclear plants on the west coast also.

When you have a small island, big mountains, large population, and limited natural resources, nuclear power is about your only option.

They cant be built in land as the terrain is quite mountainous.

Power plants also require a heat sink, so copious quantities of water are required.  Siting near coastlines or major rivers simplifies that immensely.

 

More info coming from TEPCO

[Nuclear Power Station] Fukushima Daiichi Nuclear Power Station: Units 1 to 3: shutdown due to earthquake Units 4 to 6: outage due to regular inspection * The national government has instructed evacuation for those local residents within 20km radius of the site periphery. * The value of radioactive material (iodine, etc) is increasing according to the monitoring car at the site (outside of the site). One of the monitoring posts is also indicating higher than normal level. * Since the amount of radiation at the boundary of the site exceeds the limits, we decide at 4:17PM and we have reported and/or noticed the government agencies concerned to apply the clause 1 of the Article 15 of the Radiation Disaster Measure at 5PM. * In addition, a vertical earthquake hit the site and big explosion has happened near the Unit 1 and smoke breaks out around 3:36PM. Our two employees and two cooperation workers who had been working for the foundation of safety are suffered and they are all sent to the hospital. * We started injection of sea water into the reactor core of Unit 1 at 8:20pm and then boric acid subsequently. * We continue endeavoring to secure the safety that all we can do and monitoring the periphery. Fukushima Daini Nuclear Power Station: Units 1 to 4: shutdown due to earthquake * The national government has instructed evacuation for those local residents within 10km radius of the periphery. * At present, we have decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. These measures are considered to be implemented in Units 1, 2 and 3 and accordingly, we have reported and/or noticed the government agencies concerned. * Unit 3 has been stopped and being "nuclear reactor cooling hot stop" at 12:15PM. * The operator trapped in the crane operating console of the exhaust stack was transferred to the ground at 5:13PM and confirmed the death at 5:17PM.

From http://www.tepco.co.jp/en/press/corp-com/release/11031231-e.html

So, cooling efforts underway with sea water and boric acid on the reactor which suffered the explosion, and venting to reduce pressure in the Daini plant - plus a dead worker in the exhaust stack!

The whole China Syndrome thing about the core melting through the bottom of the RX vessel and dropping to the floor as a molten blob is the stuff of Hollywood.  That's not very likely.

The BBC must have got that wrong then. Richard Black must have been watching a rerun of the China syndrome.

http://www.bbc.co.uk/news/world-12723092

By the way, as far as I know, the tsunami was not an issue for this plant.  It was the earthquake itself that caused the problem, not inundation.

It was the tsunami that caused the diesel backup generators to fail, so an issue in that sense.

The BBC must have got that wrong then. Richard Black must have been watching a rerun of the China syndrome.

Yes, several things wrong in that article, pricipally half-truths that don't tell the whole story.  The most obvious error is the diagram, which shows the turbines, generator, condenser and feed pump inside the "containment chamber".  'Tain't so, and was clearly done by someone with a very superficial understanding of the workings.

The article also neglects the presence and role of boron in keeping the core sub-critical.  Sufficient boron can shut the reactor down entirely, without the use of control rods at all.  Nuclear safety systems provide exactly that capability.  At my plant (a pressurized water reactor, not a BWR) that's how we started up - pulled the rods out with high boron concentration and then diluted to critical.  The rods are quick-acting but the boron does the same thing, i.e. captures neutrons before they can fission another uranium nucleus.

 

Everywhere I read, it is a single loop design? i.e. the primary cooling loop also powers the turbines.

That's correct, but the turbine-generator, main condenser and feed pumps are not located inside the containment as shown.

 

allardjd wrote: Everywhere I read, it is a single loop design? i.e. the primary cooling loop also powers the turbines. That's correct, but the turbine-generator, main condenser and feed pumps are not located inside the containment as shown.

I see - thanks for the clarification! I thought it was odd for it to be.

Best regards,
Vulcan.

this threads not about one of your CT fetishes.

Stop derailing the thread.

Best regards,
Vulcan.

BWRs also have multiple Recirculation loops.  They are large pumps that draw water through the fuel region and pump it back into the RX vessel at a different point.  There are no heat exchangers in those loops.  Those play a role in RX power control too when the RX is critical.  Those loops are entirely within the containment.

160 was reported on the BBC News about 90 minutes to 2 hours ago.

An update: the measurements of 1000 times background radiation in the control room was *PRIOR* to the explosion. Source of the radiation is unknown at this time, and no reports are talking about it now. Is this the source of 160 people being exposed to high doses of radiation?

There are unconfirmed reports now of a fire at a 3rd reactor.

Here is an interesting drawing, showing the primary containment.



Best regards,
Vulcan.