900krad

900krad refers to a radiation dose of 900 kilorads. A rad, or radiation absorbed dose, is a unit of absorbed radiation dose, defined as the absorption of 100 ergs of energy per gram of matter. The gray (Gy) is the SI unit of absorbed dose, with 1 Gy equal to 100 rad. Therefore, 900 kilorads is equivalent to 900,000 rads or 9,000 grays.

This dose is extremely high and would be lethal to most living organisms, including humans, if administered acutely. The median lethal dose (LD50/30) for humans, which is the dose that would kill 50% of an exposed population within 30 days, is estimated to be around 4-5 Gy, or 400-500 rads. A dose of 9,000 Gy is orders of magnitude higher than this lethal threshold.

Such high doses of radiation can cause severe damage to biological tissues by ionizing molecules and generating free radicals, which in turn damage DNA, proteins, and cell membranes. At these levels, cellular function is rapidly overwhelmed, leading to widespread organ failure and death. While acute exposure to 900krad is unsurvivable for humans, lower doses are used in medical treatments like radiation therapy to target and destroy cancer cells. The effects of radiation are also dependent on the rate of delivery, with a dose delivered over a longer period generally being less damaging than the same dose delivered instantaneously.