website statistics
Quantcast

Fukushima live updates from NHK-English

Fukushima live updates from NHK-English
image_pdfimage_print

Radiation at Fukushima No. 1 plant has surpassed legal limit, TEPCON, briefly reaching 1204 micro sievert via Kyodo

An excellent explanation of what is happening at Fukushima is available here

How do nuclear power plants work?

In fission, atoms are split in half, which generates heat; some materials that are created during this process will decay for some period of time, and they also generate heat. This heat is used to generate steam. A pressurized water reactor (water does not boil) uses a heat exchanger to generate steam in a separate chamber (a two-stage process). A boiling water reactor is a one-stage process; when it is operating, the core is kept covered in boiling water and the steam is collected above that level.

What happens when you shut down a nuclear power plant?

The self-sustaining (critical) atomic reaction that runs a reactor can be shut off in a matter of seconds; the goal is to keep the reactor sub-critical. The core material, which is radioactive, will generate heat, at a decreasing rate, for some time. Therefore, nuclear engineers need a way to keep this heat from building up in order to protect the radioactive fuel (rods) and the reactor.

The General Electric Mark I reactor design used in the Fukushima plant was determined to have a possible containment problem, should a meltdown occur, in 1986.

The unit in question is a General Electric Mark I reactor design, also called a “pressure suppression” system. It’s a pretty common model; of the 104 reactors in the US, 23 are this type. But there are concerns that design doesn’t necessarily provide the best containment in the event of a meltdown.

If they are unable to cool the core and it does melt through the reactor vessel, this model doesn’t have most robust containment system, says Bergeron. If it did meltdown and the reactor core slumped to the floor, it likely “would result in containment failure in less than a day,” he says.

Critics of nuclear power say that this has been a known issue for decades and these reactors aren’t designed to sustain a meltdown. Greenpeace’s nuclear policy analyst Jim Riccio writes:

In 1986 Harold Denton, former director of NRC’s Office of Nuclear Reactor Regulation, again acknowledged this vulnerability while speaking to utilities executives at Brookhaven National Laboratory. Denton noted that, according to NRC studies the GE Mark I reactors had “something like a 90% probability of that containment failing.”

Live Broadcasting by Ustream

Print Friendly

About magix

Profile photo of magix When my oldest son, a Marine, left for war and crossed the border from Kuwait into Iraq in March 2003 I started writing my conscience. After two tours that young combat veteran’s mother is now an ardent peace activist and advocate for social, environmental and economic justice. MGx has matured since those early vents and ramblings and now covers relevant and important local and regional matters in addition to national and global affairs.

Connect

Follow on Twitter View all Posts

2 Responses to "Fukushima live updates from NHK-English"

  1. Spilner  March 20, 2011 at 3:23 AM

    One from the woman`s can`t translate good, what she`s doing there ?

    Reply
  2. Profile wp-user-avatar wp-user-avatar-50 alignnone photo of magix
    magix  March 23, 2011 at 5:46 PM

    Her English is far superior to my Japanese

    Reply

Leave a Reply

Your email address will not be published.