The 1984 NYTimes article nl shared in this thread has more details. Excerpt: When the capsule was breached it held about 400 curies of radioactive cobalt in t

The 1984 NYTimes article nl shared in this thread has more details. Excerpt: When the capsule was breached it held about 400 curies of radioactive cobalt in the 6,010 pellets. Each pellet, according to Joel Lubenau, a health physicist at the Nuclear Regulatory Agency, produced a radiation dose of 25 rads per hour two inches from the pellet. One to 50 rads per hour is considered a significant radiation dose. In comparison, the highest exposure a bystander could have received from the nuclear accident at Three Mile Island was 100 millirads, or about one-tenth of a rad. A rad is a unit of absorbed radiation. An average chest X-ray produces 20 to 30 millirads instantaneously. A lethal dose for half the population is 450 rads received instantaneously over the whole body.