Facility Vulnerability with VISAC |
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Reports in the popular news media have indicated that large industrial facilities and nuclear power plants are prime targets for terrorist organizations. A likely avenue for such an attack is a bomb carried by car or truck, similar to the recent events listed in Table I. Car bombs require less preparation, skill, or manpower than complex attacks such as those of September 11, 2001.
The managements of industrial facilities and nuclear power plants, and as other infrastructure targets, need to know the parts of their facilities where a bomb explosion could lead to facility damage -- or in the worst case, potential of release of hazardous materials. These areas need to be identified so that they can be adequately protected.
| Date | Target/Location | Delivery/Material | TNT equiv (lbs) |
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| Apr 1983 | US Embassy Beirut, Lebanon |
van | 2000 |
| Oct 1983 | US Marine Barracks Beirut, Lebanon |
truck, TNT with gas enhancement | 12000 |
| Feb 1993 | World Trade Center New York, USA |
van, urea nitrate and hydrogen gas | 2000 |
| Apr 1995 | Murrah Federal Bldg Oklahoma City, USA |
truck, ammonium nitrate fuel oil | 5000 |
| Jun 1996 | Khobar Towers Dhahran, Saudi Arabia |
tanker truck, plastic explosive | 20000 |
| Aug 1998 | US Embassy Nairobi, Kenya |
truck, TNT, possibly Semtex | 1000 |
| Aug 1998 | US Embassy Dar es Salaam, Tanzania |
truck | 1000 |
| Oct 2000 | Destroyer USS Cole Aden Harbor, Yemen |
small watercraft, possibly C-4 | 440 |
To determine the areas where chemical or nuclear facilities are vulnerable, a calculational tool is needed that can quickly evaluate the effects of a bomb explosion in or around the buildings of a facility and determine the probable impact on facility operation as well as the probability of an accompanying chemical or radiological release. The Visual Interactive Site Analysis Code (VISAC) developed at Oak Ridge National Laboratory (ORNL) does this using a geometric model of the facility coupled to an event/fault tree model of plant systems to analyze the effects of blasts. The event/fault tree models associated with facility vulnerability calculations often involve unreliable systems (systems with high component failure probabilities resulting from an attack scenario). For VISAC to analyze such situations accurately, ORNL had to develop some novel techniques for evaluating event/fault trees associated with unreliable systems.
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Murrah Federal Building |  |
Murrah Federal Building |
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Khobar Towers |  |
Destroyer USS Cole |
Oak Ridge National Laboratory, 2004
