Archief - Aardbeving in Japan

Phil zei:

fucking morons

http://img846.imageshack.us/img846/323/americunts.jpg

Onvoorstelbaar sommige mensen...

Nog, op CNBC

“The human toll here looks to be much worse than the economic toll, and we can be grateful for that.” →
So says CNBC’s Larry Kudlow of the Japan earthquake. If you listen closely at the end, you can hear his co-anchor add, “This is good news for the US economy.”

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The media has been terrifying about this so I have spent the day reading about it. This is the best description I have seen, from a nuclear engineer in the US Navy:



The Fukushima Daiichi power plant is a Boiling Water Reactor. It is both moderated (what causes fission) and cooled (what stops the nuclear fuel/waste from getting so hot it melts) by water.



The plant was scrammed (immediately stopped) after the earthquake by inserting control rods (boron-infused 'rods' that prevent further fissions from taking place (by eating up all the neutrons necessary to initiate fission). This happened successfully. The plant is "shut down."



However, after the plant is shut down, there are still certain elements called "delayed neutron precursors" that will STILL released neutrons for some time period after the plant is shut down. These are what cause heat to accrue in a reactor that should theoretically be "shut down". This is why cooling needs to be provided in a typical 2nd generation light-water reactor (what most reactors in the world are) for a good while after shutdown.



Without cooling water, the likely "worst case" will be the reactor pressure vessel (RPV) building up heat, which builds up pressure, which could cause a rupture of the vessel. The fuel rods will spill out radioactive contents, fires might break out, and the reactor is basically a lost cause.



And how does that affect the general populace in terms of radioactive dose?

-Not at all.



The RPV is surrounded by a containment facility designed from the ground up to withstand everything short of hydrogen bombs. Given the semi-spherical distance from the RPV an explosion would have to travel to break through the containment vessel, it is fundamentally impossible (given the energy density the RPV is capable of containing) for there to be straight up "radioactive smoke" or such getting outside of containment. The containment building is constructed to prevent EXACTLY this emergency.



So while this is a worrying emergency, and could represent billions of lost dollars a mess to clean up should the WORST come about, it will still not be another Chernobyl. And given the efforts underway to provide cooling and the fact that the fuel rods are still not exposed to air (When the real danger of fuel melting can occur), there is still time to stop this loss of coolent accident (LOCA).



Here are a few more calming points for people who are expecting a huge disaster (from a different author, I don't know qualifications)



There are three important things that made the Chernobyl accident possible that the Fukushima reactors do not have.



* Chernobyl was designed with a positive void coefficient. This means that when the neutron moderator was removed, the reaction got stronger. The Fukushima reactors have a negative void coefficient, which means that if you remove the neutron moderator, the reaction slows and eventually stops.



* Chernobyl's core was built on top of a tank of water. This was meant to cool the core if it melted through the containment vessel. Instead, it caused a tremendous steam explosion which tore the facility apart. The Fukushima reactors do not have this and will therefore not explode like that, even if the core melts through the containment vessel.



* Chernobyl used graphite as a neutron moderator. Graphite is flammable, and when the reactor exploded, the radioactive graphite burned and ended up in the atmosphere. The Fukushima reactors use water as a neutron moderator, which is obviously not flammable.



I will continue to look for good info and post it here.

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Frado2005 zei:

HLN is wel de laatste krant die je moet opendoen voor dergelijk nieuws

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Nasty Nas zei:

Het is overal zo hoor
Experts vrezen dat Japan op nieuwe Tsjernobyl afstevent - Aardbeving Japan - De Morgen

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ilgonwe zei:

De Morgen en HLN zijn van dezelfde uitgever, dus de berichten zullen wel gelijkaardig zijn.

Tsjernobyl zal het wel niet worden en de laatste berichten geven aan dat de reactoren stilgelegd maar compleet onbruikbaar worden. Japan heeft een heel aantal kerncentrales staan aan de kuststreek. Die zullen waarschijnlijk grondig aangepakt worden om de koeling te garanderen als ze getroffen worden door een tsunami. Ik kan me wel niet voorstellen dat ze in de toekomst nog kerncentrales willen bouwen op het strand zoals Fukushima I en II.

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daFour zei:

LIVE :: YokosoNews - Japanese Culture, Lifestyle and Entertainment laatste nieuws

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