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Graphical Expert System for Analyzing Nuclear Facility Vulnerability. David Sulfredge Oak Ridge National Laboratory December 3, 2002. O AK R IDGE N ATIONAL L ABORATORY U.S. D EPARTMENT OF E NERGY. Facility Vulnerability Analysis. Objectives
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Graphical Expert System for Analyzing Nuclear Facility Vulnerability David Sulfredge Oak Ridge National Laboratory December 3, 2002 OAK RIDGE NATIONAL LABORATORY U.S.DEPARTMENT OF ENERGY
Facility Vulnerability Analysis • Objectives • Develop models to predict facility response to military or terrorist weapons • Determine critical locations for enhanced protective measures • Predict collateral effects
Nuclear Facilities are Vital Assets • Must safeguard U.S. plants • About 20% of U.S. generating capacity • Considerable public concern • Need targeting tool for some facilities • Defeat energy infrastructure • Defeat WMD production • Potential for serious radiological consequences • ORNL developing Visual Interactive Site Analysis Code (VISAC) to meet these needs
VISAC Integrates the Following Functions in one Code • Facility Kill Probability • Facility Collateral Effects Estimates • Facility Downtime Estimates • Facility Model Editor • Event/Fault Tree Editor Provides VERY FAST “what if” Analysis for Various Accident/Incident Scenarios
VISAC Core damage probability Facility kill probability 5
VISAC Weapon Selection • Equipment sabotage option • Blast location • Chosen from model editor • Chosen from viewer • Type of blast calculation • Uniform ray trace mode • Direct ray trace mode • Air region mode
VISAC Blast Propagation • Uniform ray tracing • Directed ray tracing • Air region method
VISAC Downtime Calculation • DT based on fault tree for facility kill • Single component failure • Multiple component failure • VISAC uses a weighted DT sum DTnet = (1/ Pkill ) Pi* DTi • Compute both serial and parallel repair times to bound answer
VISAC Geometric Model Viewers Image from 3-D Viewer, showing an image of the entire plant Image from 2-D Viewer, showing a triple orthographic projection of a turbine building
Viewing Components by Floor Level Second Floor First Floor Third Floor
Building Critical Component List by Floor Title and highlighted critical component point to each other
VISAC BRL-CAD Model Editor Creates Customized Models in BRL-CAD in Minutes Instead of Days • Model editor • Create new models • Customize existing models • Move, delete objects • Creates a BRL-CAD output file 12
Construct Facility from VISAC Library Buildings • Buildings chosen from libraries • Building positions and orientations • can be varied • Screen grid available to aid • building placement • Ground level and building • “sinkages” can be edited
VISAC Event/Fault Tree Editor Creates Customized Event/Fault Trees for use with Customized Geometric Models • Tree editor • Create new tree • Customize existing trees • Delete trees • Add/Edit consequences • Change failure probability 14
VISAC Event Tree Editor • Edit targets on canvas • Green arrow (Add or delete column) • Green fork (Split the branch) • Red X (Collapse the branch) • Consequences • assigned by the user
VISAC Fault Tree Editor • Fault trees can be modified • New gates added • New subtrees can be added • Options to copy and paste • Add new basic events
Example VISAC Calculation (1) • Sabotage Option • Switchyard (S) 50% • Steam Generator (SG1A) 50% • Overall Kill Probability 75% • Downtime • Serial repair 7.33 months • Parallel repair 6.67 months
Example VISAC Calculation (2) • Most likely sequence leading to core damage highlighted in red
Simple vs. Detailed Model VISAC Damage Maps for a Generic Two-Loop PWR Building-level geometry Detailed plant geometry
Conclusions • VISAC successfully integrates geometric modeling, damage assessment, and event/fault tree consequence analysis • VISAC’s graphical editing routines can customize library models as needed • VISAC can analyze a wide variety of nuclear facility vulnerability scenarios • Code development work is continuing