Graphical Expert System for Analyzing Nuclear Facility Vulnerability

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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
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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

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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

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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
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VISAC
Core damage probability
Facility kill probability
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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

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VISAC Blast Propagation

• Uniform ray tracing
• Directed ray tracing
• Air region method

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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

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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
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Viewing Components by Floor Level
First Floor
Second Floor
Third Floor
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Building Critical Component List by Floor
Title and highlighted critical component point
to each other
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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

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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

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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

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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

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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

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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

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Example VISAC Calculation (2)

• Most likely sequence leading to core damage
  highlighted in red

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Simple vs. Detailed Model VISAC Damage Maps for a
Generic Two-Loop PWR
Building-level geometry
Detailed plant geometry
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Conclusions

• VISAC successfully integrates geometric modeling,
  damage assessment, and event/fault tree
  consequence analysis
• VISACs 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