Fukushima N.B. (nota bene: no bias/no bullshit)

On March 11, 2011, the Fukushima Dai-ichi nuclear power plant in Japan was hit by a 46’ wave tsunami and a 9.0 magnitude earthquake, setting off a series of crises. This was the fifth largest quake in recorded history. The power plant, operated by Tokyo Electric Power Company (TEPCO), trembled, fell, and melted down.

Fuel rods China syndromed their way out of containment vessels, reaching groundwater. Japan is in dire straights.

Reference Information/Units

Define a radiation measurement using a bunch of different names

No universal terminology for units of radioactivity means that a lot of different countries express radiation exposure and radiation doses in different units. That makes it hard to see at a glance the danger level indicated by the measurement.

Soviets used older terms. So information about the nuclear accident at Chernobyl describes radiation exposure and level of environmental contamination in roentgen (R) and curie (Ci).

Western habit is to use becquerel (Bq) for radioactivity—where a gray (Gy) is the absorbed dose and sievert (Sv) for dose equivalent.

Absorbed dose - how much radiation per unit mass of tissue or organ. Usually absorbed dose will be given in rads or grays where one gray = 100 rads.

Dose equivalent - how much harm tissue suffers depends on how big the radiative particle are, since a big neutron can smack tiny systems at the atomic level more hurtfully than smaller radiative particles such as electrons. The dose equivalent incorporates a multiplying factor and is measured in sieverts (Sv). Example) 1 Sv gives the same biological effect independent of the kind of radiation that’s causing it.

Alpha (radiation) particles are high energy helium nuclei and are biggish. They have low penetration ability because they are big. But once inside tissue, they cause the worst damage. Ingestion of alpha radiation is extremely dangerous.

Beta radiation: an atom releases a (tiny) electron or positron.

Gamma radiation: an atom releases a (tiny) energetic light particle like an x-ray or gamma-ray. Gamma radiation is high energy.

Becquerel (Bq) is one radioactive disintegration per second. One Bq of alpha produces more radiotoxicity inside your body than does one Bq of beta radiation.

Curie (Ci): a unit of radioactivity where 1 Ci = 37 billion Bq (disintegrations per second)—3.7 x 10^10.

Rad: radiation absorbed per dose. Unit indicating the amount of radiation dose absorbed by a unit of body tissue/organ. *the amt. given in Ci or Bq to produce 1 rad per organ is different than the amt. that would be needed to produce 1 rad per whole body.

Radiation or radioactivity: energy emission of neutron, alpha, or beta particles or gamma rays.

Rem: roentgen equivalent man. Rem is the dose received that produces the same biological effect as 1 rad of X-rays.

Roentgen: unit of X-rays/gamma produced. 1 R of gamma is more or less the same as 1 rem or 1 rad.

Sievert (Sv): 1 Sv = 100 rem.

MAX ALLOWED

0.1 rem = deemed annual safe dose from natural environmental exposure

0.5 rem = deemed maximum safe annual dose for the public

5.0 rem = deemed maximum annual limit for nuclear industry workers

LETHAL AMOUNTS

0.5 - 10 rem = no specific increase in cancer incidence or genetic effect

10 - 100 rem = specific increase in cancer incidence & genetic effects

100 - 200 rem = radiation sickness and opportunistic infections

200 - 400 rem = accute radiation sickness and opportunistic infections

400 - 600 rem = lethal for bone marrow

more than 600 rem = lethal for intestines