Posted tagged ‘nuclear bomb’

Mapping an explosion: blast map calculators

June 16, 2008

I found some interactive blast map calculators that were mildly entertaining to my inner-geek. Unfortunately, I couldn’t achieve 100% functionality, which might be because I’m on a Mac (I’ve not tried them on a PC yet). Nonetheless, they’re link-worthy:

Fallout Calculator – from the Federation of American Scientists (FAS). You can choose from a selection of major international cites (New York City is noticeably absent), wind speed, wind direction and bomb yield. On my Mac I could not adjust the bomb yield (I tried using both Safari and Firefox). The results, a series of concentric ovals, “depict calculated radiation doses of 300, 25, and 1 REM at 96 hours after detonation.” Clicking anywhere on the map will move the location of detonation to that point. FAS, an organization endorsed by 69 Noble Laureates, was founded in 1945 by scientists who had worked on the Manhattan Project to develop the first atomic bomb. A main focus of the group is to reduce nuclear weapons.

Nuclear Weapon Effects Calculator – also from the FAS. This tool is “to give an idea of the devastating blast effects of ground-level, shallow subsurface, and low-altitude nuclear weapon detonations.” Choose a city (New York again is absent) and a bomb yield. Clicking anywhere on the map will move the location of detonation to that point. The results are three concentric circles, which are not explained.

The High-Yield Detonation Effects Simulator (HYDESim) – an experiment in AJAX and Google Maps programming by Eric A. Meyer. Based on public data (from the classic book, The Effects of Nuclear Weapons), it shows “overpressure,” which is the destructive air pressure or shock wave created by the bomb measured in pounds per square inch (psi). You pick the bomb yield and four concentric circles show the overpressure created at four distances from the point of detonation. I had difficulty moving the point of detonation around the google map. You can find additional coordinates (latitude and longitude) for cities by clicking here. It’s interesting to note that a 10 kiloton bomb creates 0.25 psi at 4.01 mile and “most glass surfaces, such as windows, will shatter within this ring, some with enough force to cause injury.” Note to self: if the U.S. is ever threatened with an imminent attack, move desk away from window.

Blast Maps – from the website for the book, Nuclear Terrorism: The Ultimate Preventable Catastrophe, by Graham Allison of the Belfar Center for Science and International Affairs at the John F. Kennedy School of Government. Internet Explorer and a PC are required so I’ve not messed with this one yet

Nuclear Bomb Effects Computer – online retro edition – Wow, this is cool. During the Cold War you could purchase a circular slide rule from the U.S. Government Printing Office based on information from the classic book, The Effects of Nuclear Weapons (same source for the HYDESim above). John Walker has recreated this calculator online in a unique way: for blast affects you input the variables of bomb yield and distance, and for radiation affects you input time and dose rate. The output is an image of the original slide rule showing the results. Click here for the instructions.

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Will I survive a nuke? Estimating what size nuke to plan for

April 5, 2008

I want to know if I’ll survive a nuclear blast just three miles from ground zero. The first step is to estimate the size of the bomb that would most likely be used in an attack.

Disclaimer to Self: If I’m wrong about my conclusion, i.e., if a larger bomb is used, well, I could unexpectedly get nuked.

Nuclear bombs range in size from .25 kilotons to 100,000 kilotons (100 megatons). Hiroshima was 12.5 kilotons and Nagasaki was 22 kilotons. A suitcase nuke is about 1 to 3 kilotons. Given a particular size bomb, there are variables that affect the extent and type of damage such as weather, terrain (including tall buildings) and where, in relation to the ground, the bomb is detonated. A groundburst causes less blast damage to the surroundings but it creates more debris so nuclear fallout is worse. An airburst causes more blast damage but less fallout.

During the Cold War the possibility of state-sponsored nuclear war gave a legitimate fear of large bombs, in the megaton range. Today, with terrorism a greater risk, I think the smaller the bomb, the greater the risk (if anyone can correct me on that, please do). While very small bombs can be hard to make as you need a minimum amount of fissile material for a bomb to work, larger bombs need more enriched uranium, which is hard to get. Also, terrorists would likely deploy a nuke tactically, so the smaller the bomb the easier it is to sneak into place.

I believe 10 kilotons is the size to plan for. A bomb of this size is small and simple so it could be “homemade” and snuck into place. A couple of important studies, one from the Preventive Defense Project, a joint Stanford-Harvard program, and one from the RAND Corporation, a non-profit think tank, both chose 10 kilotons as a likely size. It’s also roughly the size of Hiroshima so we have firsthand information about the actual damage caused by that load. While Hiroshima was an airburst (about 1900 feet), the Preventive Defense Project modeled their results on a bomb at ground level or in a tall building, hundreds of feet in the air.

Planning for 10 kilotons provides a margin of safety because I think there’s a greater probability of something smaller than 10 kilotons, like a suitcase nuke (I keep wondering, where are all the Russian suitcase nukes?). Also, an untested, homemade 10 kiloton bomb by a non-state group may “fizzle” and produce a lower yield, which is what happened to the North Korean underground test in 2006. And bomb much larger than 10 kilotons could fizzle and yield 10 kilotons or less.

The target I live near is on the water so it would not make sense to use a large bomb as half the blast would be wasted over the water. You hear that, you would-be-bombers? Don’t waste your money on big bombs near the water.

After the Bomb

September 12, 2007

Click here for an interesting New York Times op-ed piece from 6/12/07, ”After the Bomb”, by three retired bigshots, a former defense secretary, a former assistant defense secretary, and a former director of the Lawrence Livermore National Laboratory.

These gentlemen say the probability of a nuclear attack “is larger than it was five years ago.” They suggest the formation of a contingency plan for the inevitable chaos on the day after: “Sadly, it is time to consider such contingency planning. First and foremost, the scale of disaster would quickly overwhelm even the most prepared city and state governments.”

If a former secretary of defense and his colleagues are requesting the formation of a contingency plan, it makes me wonder, do we currently have a plan? Or maybe they think we have an inadequate plan. Or, maybe, because they think you can’t plan the day after, they feel a new plan should be devised to plan that the day after is unplannable. I’m getting the warm, radioactive fuzzies all over.

They give good survival info if you survive the blast. They bring up an important point, which is to know which way the wind is blowing to determine if you’re in the path of the fallout:

“Those lucky enough to be upwind could remain in their homes if they knew which way the fallout plume was blowing. (The federal government has the ability to determine that and to quickly broadcast the information.) But for those downwind and more than a few miles from ground zero, the best move would be to shelter in a basement for three days or so and only then leave the area. This is a hard truth to absorb, since we all would have a strong instinct to flee. But walking toward the suburbs or sitting in long traffic jams would directly expose people to radiation, which would be the most intense on the day after the bomb went off.”

More about determining wind direction in my next post.

They state there will be choices for individuals regarding what to do, which should take into consideration radiation exposure and the chance of long term health risks, specifically cancer:

“The choices would be determined by the dose of radiation they were willing to absorb. Except in the hot zone around the blast and a few miles downwind, even unsheltered people would not be exposed to enough radiation to make them die or even become sick. It would be enough only to raise their statistical chance of getting cancer later in life from 20 percent (the average chance we all have) to something greater — 21 percent, 22 percent, up to 30 percent at the maximum survivable exposure.”

Finally, they bring up a very interesting point. A nuclear attack in one city could inflict fear of more bombs in other cities and could incite the mass or partial evacuation of our major cities:

“Next comes the unpleasant fact that the first nuclear bomb may well not be the last. If terrorists manage to obtain a weapon, or the fissile material to make one (which fits into a small suitcase), who’s to say they wouldn’t have two or three more? And even if they had no more weapons, the terrorists would most likely claim that they did. So people in other cities would want to evacuate on the day after, or at least move their children to the countryside, as happened in England during World War II.”

I think this concept is a biggie in putting together a survival strategy: Everybody should be prepared to stay in their homes for an extended period of time without emerging; and everybody should be prepared to evacuate their homes immediately.

For some grim, depressing comments on this New York Times piece and what the day after would be like, click here for a column by the Bulletin of the Atomic Scientists. Although I agree that survivors in the immediate area will be too traumatized to act rational in the ensuing chaos, there will be a distance from the blast where people will not be as traumatized and will need to make immediate decisions. Common sense says that those who are prepared will fare best.

What’s a safe distance from a nuclear bomb? That will be the subject of numerous futures posts.