Comment This is not Chernobyl (Score 5, Informative) 136
I seem to notice that there is a lot of FUD and misinformation out there (not just from mdsolar and Beyond Nuclear) regarding nuclear power. This is helped in part because of ignorance by the general public. It's important to understand that there is a wide range of radioactive sources. Most of them are naturally occurring, or occur is such small amounts that they present no health hazard.
Radiation exposure is usually measured in Rem (or mRem). Let's take a look at some common activities and see how they compare.
One chest X ray (8 mRem)
One mammogram (70 mRem)
One X ray of the abdomen (300 mRem)
One renal nuclear medicine procedure (310 mRem)
One CT head scan (3000 mRem)
CAT scan of whole body (5000 mRem)
As you can see, there is a wide variance of radiation sources. Most people in the US receive approximately 300 mRem / year from natural background radiation sources (primarily from radon and sun exposure.) So, how much radiation exposure do you need to cause bodily damage?
There is no agreed-upon level which is considered "safe", however there is relatively clear agreement on thresholds where radiation has noticeable effects on the human body. (NOTE: These are listed in Rem, not mRem)
Changes in blood chemistry (5-10 Rem)
Nausea (50 Rem)
Fatigue (55 Rem)
Vomiting (70 Rem)
Hair loss (75 Rem)
Diarrhea (90 Rem)
Hemorrhage (100 Rem)
Possible death (400 Rem)
Death within 1-2 weeks (1000 Rem)
Damage to central nervous system (2000 Rem)
Death within days (2000 Rem)
But what about cancer? The risk for cancer can be increased by radiation exposure, which resulted in increased mutation rates of cell growth. The EPA estimates that in a group of 10,000 people 2,000 of them will die from cancer. If each person received 1 Rem (not mRem) of non-natural ionizing radiation exposure accumulated over their lifetime, 2,006 people would die from cancer.
So, now that we have an idea of just how bad different levels of radiation exposure are, what about these tritium leaks that have got certain people so upset? The highest reading that these monitoring wells have read was 2.45 microcuries / liter. This translates into roughly 425 mRem / year (assuming it was not diluted). 425 mRem is substantially higher than the current NRC limits, but still much too low to present a health hazard.
When people hear words like "nuclear reactor piping leak" they naturally assume that high-level radioactive particulates are getting out to the environment. The fact is that the incident at Vermont Yankee represents a very small health hazard to the public.