Use of Acoustic Wave Analysis in Safeguards Applications

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Use of Acoustic Wave Analysis in Safeguards
Applications
Michael Goldfarb Marius Stein Canberra
Albuquerque, Inc.

• International Safeguards Workshop
• Advanced Sensors for Safeguards
• Santa Fe, New Mexico USA
• 23 April - 27 April 2007
• sponsored by The U. S. Support Program
• On behalf of the International Atomic Energy
  Agency

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Canberra Albuquerque, Inc.

• Member of the AREVA family
• AREVA
• World leader in nuclear power
• 9 billion company
• 50,000 employees in more than 30 countries

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Containment Verification in Safeguards

• Containment verification (CV) measures
• Secure materials or equipment against tampering
• Indicate any attempt to tamper with a containment
• Do not provide physical protection
• Areas under containment
• instrument cabinets
• nuclear material storage containers
• conduits
• Maintaining containment integrity as important to
  safeguards as seals
• No quantitative verification methods are
  currently in use
• Methods to verify the integrity of a containment
  must be developed

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Current CV Methods

• On-site
• Carried out by inspectors
• Main methods are qualitative
• Sensory basis
• Visual check for changes or relocation
• Olfactory chemical smells can indicate cleaning
  or repainting
• Touch (feeling surface for changes)
• Auditory (listening for rumors and information
  from operators)

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Role of Inspectors in Containment Verification

• Inspectors must be trained to extract as much
  containment information from on-site operators as
  possible
• Enhanced observational skills training provided
  by inspection authority
• No way to reconfirm activities undertaken on site
• Mutual trust between operators and inspectors is
  necessary

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Acoustic Wave Analysis Introduction

• Technology driven primarily from military
  submarine applications
• Method
• Acoustic source establishes an energy
  distribution within an enclosure
• Any opening or entry into the volume disturbs
  this distribution and is marked as an intrusion
• Appropriate for use in Containment Verification
• Ideal for situations with very specific signals
  of interest or areas with very low background
  noise
• For a machine operating at a stabilized speed,
  spectrum can be averaged to find machines normal
  rotation speed

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Advantages

• Advantages
• Video surveillance does not directly monitor
  parameters (i.e., equipment status)
• Not limited by line-of-sight
• Some events are detectable only through audio
  signals
• Noise can draw inspectors attention, allow
  quicker and more accurate post analysis
• Acoustic sensors can significantly enhance system
  performance
• Passive, non-intrusive

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Acoustic Wave Analysis in Industrial Processes

• Aids in preventive maintenance to detect wear of
  main mechanical parts helps to plan actions
  before a fault occurs
• Acoustic wave analysis system already used in
  industry proven and mature technology
• Access to the system can be performed remotely
  through a web link.

Wave Analysis System at Industrial Site
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Obstacles

• Major obstacle Differentiating between multiple
  audio sources present in acoustic signal
• Sources of interest
• False alarms
• Background noise
• Sound generation is associated with the movement
  of parts in a wide frequency range (10Hz to
  several KHz, due to damping and frequency
  reflections)
• Specific processing methods designed to reject
  background noise
• Method Extract key parameters that allow for
  verification from the signature
• Meeting industry acoustic comfort concerns
• System developed to meet concern

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Differentiation
Door Closing
Metal Shock
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Extracting Key Parameters from Signature

• Two main methods
• Statistical approach based on a library of
  recorded reference signals that are used to
  extract as many parameters as possible
• A physical model of the sound generation that
  allows the determination of the signal main
  characteristics.
• Both method extract n parameters from measured
  goal

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Extracting Key Parameters from Signature

• Third method concentrate on a specific device
• Signature can be recorded on-site
• Signature of equipment while running serves as a
  reference model
• Signal variation indicates mechanical
  modifications

Sound sources marked within camera image
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Conclusions

• Acoustic wave analysis systems used widely
  throughout industry
• Well-suited to control known installations where
  reference noise and vibrations can be recorded as
  a learning process
• Possible applications range from triggering to
  tamper protection and preventative maintenance
• Next step
• Define a typical safeguards scenario
• Perform testing on real data