BombCAD -- A NEW TOOL FOR BOMB DEFENSE IN NUCLEAR FACILITIES

This paper describes a new tool for analysis of the specific vulner- ability of diverse facilities to bomb attack and for computer-aided-design (CAD) of siting, screening and hard- ening/softening aspects of comprehen- sive bomb defense programs. BombCAD combines the extensive architectural and engineering data base and graph- ics capabilities of modern architec- tural CAD systems with the bomb effects computational capability of the 'SECURBPLAN' BOMB UTILITY. BombCAD permits architects/engi- neers, security professionals and facility managers to analytically estimate and graphically display facility vulnerability and changes (reductions) in vulnerability which result from the adoption of various bomb defense measures. The system, based on a Compaq 386 (or compatible) computer, de- velops a special bomb analysis drawing layer and data base from either an existing architectural CAD data base, facility construction drawings or a field survey. It uses well known bomb scaling laws to compute blast wave parameters (over- pressure, impulse, positive phase duration and time-of-arrival) of credible potential bomb blasts on both loadbearlng and non-loadbearing structural elements. BombCAD provides approximate three-dimensional assess- ment of bomb effects including inte- rior blast venting, external barriers and topography. It estimates struc- tural failures from both internal and external bomb blasts using a simple and conservative \"zone of Involve- ment\" (ZOI) model based on damage thresholds for various construction materials and techniques. It provides analytic design inputs for explosives screening programs to minimize bomb vulnerability. BombCAD assists archi- tects and engineers in facility lay- out (architectural programming) to minimize the potential for bomb damage and personal injury by pro- viding primary (load-bearing) struc- tural design inputs, as well as, fascia, glazing and internal struc- tural design guidelines.