Fire Earth

Earth is fighting to stay alive. Mass dieoffs, triggered by anthropogenic assault and fallout of planetary defense systems offsetting the impact, could begin anytime!

Posts Tagged ‘Cesium-137’

UPDATE: Japan Nuclear Disaster

Posted by feww on April 5, 2011

UPDATE 12:00UTC

TEPCO has revealed that it had found radioactive iodine-131 at 7.5 million times the legal limit in seawater samples taken on Saturday near the stricken Fukushima NPP.

Samples taken on Monday showed the radioactive level at 5 million times the legal limit. The new samples also  contained radioactive cesium-137  at 1.1 million times the legal limit, the company said.

Why have oceans if you couldn’t…

Japan to dump 11,500 tons of “low-contaminated water” into the Pacific ocean

Workers at Fukushima Dai-ichi NPP have begun dumping “low-radioactive” water  into the ocean allegedly to free up  storage room for  more highly radioactive water.

TEPCO says they are dumping 11,500 tons of radioactive-water, currently held at the crippled Fukushima NPP storage facilities, into the Pacific ocean so that the more radioactive-water that is leaking from Reactor 2 can be stored in its place.

Does that mean when even more highly radioactive water is found at the site they can dump the second load into the ocean?

Meanwhile in Germany…

“A decision has been taken to shut down eight plants before the end of this year and they definitely won’t be reactivated. And the remaining nine will be shut down by the end of the decade,” a German deputy environment minister, told Reuters on Monday.

“Japan has shown that even if there is a miniscule occurrence, the residual risk is too high to justify the continuation of nuclear power […] It is better to go for other energy services in a civilized country,” Juergen Becker said.

What is a lethal dose of radiation from a single Exposure?

Studies of the 1945 atomic bombing at Hiroshima and Nagasaki show that 100 percent of victims whose bodies were exposed to 600,000 millirems (6,000 mSv) died from radiation. About 50 percent of victims who received  450,000 millirems (4,500 mSv) of radiation also died.

(Note: Rem is a unit of ionizing radiation equal to the amount that produces the same damage to humans as one roentgen of high-voltage x-rays.  Source: MIT)

1 rem = 10 mSv  (1 Sv = 100 rem)

Background Radiation in millirems per year (mrem/yr)

  • Average background radiation (US):  300
  • Higher altitudes (e.g, Denver): 400

“Safe Levels” of Radiation (U.S.)

Limits above natural background radiation levels (average 300 millirems per year) and medical radiation:

  • Occupation Limit: Maximum of 5,000  (the limit for a worker using radiation)
  • Average Natural Background: 300

[Note: Lifetime cumulative exposure should be limited to a person’s age multiplied by 1,000 millirems, e.g., a 70-year-old person, 70,000 millirems.]

Adults

  • Max single dose for an adult: 3,000
  • Annual total dose: 5,000

Under 18

  • Max single dose for a person aged under 18 years: 300 millirems (whole body equivalent)
  • Annual total exposure: 500

Fetal Exposure

  • Maximum limit for fetal exposure during gestation period:  50 millirems per month above background levels

Medical

  • Single Chest X-ray (the whole body equivalent): 2 millirem

Air Travel

  • Coast-to-coast US round trip flight: 12 millirems

*Note:  Radiation dose of about 2,000 millisieverts (200,000 millirems) cause serious illness.

Half-life of some radioactive elements

[NOTE: Half-life is the time taken for a radioactive substance to decay by half.]

  • Cesium-134 ~ 2  years
  • Cesium-137 ~ 30 years
  • Iodine-131 ~ 8 days
  • Plutonium-239 ~ 24,200 years
  • Ruthenium-103 ~ 39 days [Ruthenium is a fission product of uranium-235.]
  • Ruthenium-106 ~ 374 days
  • Strontium-90 ~ 28.85 years  [Strontium-90 is a product of nuclear fission and is found in large amounts in spent nuclear fuel and in radioactive waste from nuclear reactors.]
  • Uranium-234 ~  246,000 years
  • Uranium-235 ~ 703.8  million years
  • Uranium-238  ~ 4.468 billion years

Related News Links

Fire-Earth Links

Posted in Chernobyl, Chernobyl nuclear disaster, chernobyl victims, environment, Half-life | Tagged: , , , , , , | 1 Comment »