Answer to Question #4074 Submitted to "Ask the Experts"

I live in Westchester, New York, the home of the Indian Point nuclear power plant, and 30 minutes outside New York City. After reading Osama's Revenge (which fortells of nuclear terrorism in the United States) and hearing on the radio of the possibility of an attack on Indian Point, I purchased a Gamma Scout radiation meter. It reads µSv which are I think are millisieverts. If there actually was an event, would it make sense to just leave or stay put and wait for the level of radiation to diminish? If the level does not diminish it makes sense just to leave—wouldn't you agree? What would be a safe level to travel in µSv? I noticed that the meter also has mSv or microsierverts—so not sure if the answer to the question makes sense in µSv or mSv?

There are a few things here that are worth mentioning that are directly or indirectly relevant to your concerns.

The first thing is that the risks from an attack on Indian Point are greatly overrated. These risks have been described by a few writers, the latest being the Union of Concerned Scientists (UCS). In each case, I believe the writers have chosen highly improbable worst-case scenarios that are simply not credible. For example, the UCS assumed that terrorists would have the ability to place a planned attack on "hold" while waiting for the ideal weather conditions and that those weather conditions would remain ideal for several hours. They further assumed that the terrorists would be able to somehow gain sufficient control of the reactor to cause a serious problem, that this problem would be sufficient to release a major fraction of radioactivity from the core, and that this whole sequence of events would be coordinated with a second terrorist group that would breach the containment structure (several feet of reinforced concrete) at just the right time. With all of these assumptions, the UCS reported that the median number of deaths would be on the order of several hundred and that the worst-case scenario would be tens of thousands of deaths. What they did NOT report was that it was equally likely that only a few people would die from such an attack. They only reported the more dramatic upper numbers. We do not know how likely it is that an attack will take place, but I think that radiation safety and nuclear power professionals will agree that an attack is almost certainly not going to cause widespread death and destruction.

I should also point out that the Chernobyl accident killed only 31 people directly and will likely cause only a few thousand cancer deaths over 50 years. Chernobyl was far worse than a terrorist attack on Indian Point could be because Chernobyl reactor did not have a containment structure—I visited a Chernobyl-style nuclear reactor in 2001 and I was amazed at how much better protected and better contained our nuclear reactors are. Even with the help of terrorists, a Chernobyl-style accident simply cannot happen in US nuclear power plants.

Okay—so let's talk about your radiation meter!

First, µSv is microsieverts. One µSv is equal to one-tenth of a millirem. Natural background radiation (from rocks, soils, cosmic rays, etc.) is usually about a tenth of a µSv or so. A radiation dose of up to 50,000 µSv can be called safe—this dose is not enough to measurably increase your chances of getting cancer later in life. A radiation dose of 1 million µSv is what's needed to give a person mild radiation sickness (1 Sv or 100 rem). It takes a dose of 5 Sv (5 million µSv or 500 rem) to be fatal to 50% of the people exposed if they do NOT receive medical treatment, and with good medical care a dose of 8 Sv is fatal to 50% of the exposed population. In other words, as long as you can read the dose rate on your meter (that is, as long as it is not "pegged out" on the highest scale), you are safe.

If there is an attack on Indian Point, the best thing to do is to go inside and close your doors and windows. Turn on the radio or TV to find out what's going on and to see if you are in an area that needs to evacuate—this information will be given out repeatedly on local TV and radio stations. If you do not need to evacuate, you should stay put because the risks from driving are a lot higher than the risks from even moderate radiation exposure. Also, by driving, you are making it difficult for emergency response vehicles to reach the scene or to take injured people to the hospital. I know that it is hard to just sit in your home and do nothing, but in the event of a terrorist attack on Indian Point, that is precisely the best thing to do unless your emergency response officials tell you to do otherwise.

P. Andrew Karam, PhD, CHP