An introduction to DIAMOND Personnel Safety System

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An introduction to DIAMOND Personnel Safety System

• By Martin Wilson
• Principle Personnel Safety Engineer

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Contents

• The Requirements
• Hazard Management
• Access Zones
• Personnel Safety Hardware
• Test strategy
• EPICS

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The Requirements

• Why do we need PSS?
• 1. We cant separate the hazard from the product
• 2. Required by LAW
• Legal Requirement under Health and Safety at
  Work act 1974 / IRR99
• Senior management are liable to prosecution and
  punishment
• Persons ignoring or interfering with processes or
  equipment may also be liable to prosecution

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The Requirements

• Personnel Safety, the Legal and Site Requirements
• Designation of controlled and supervised areas
• Prior examination of plans
• Risk assessments and hazard management
• Conduct of investigations
• Regular calibration of equipment
• Periodic examination and testing

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Hazard Management

1. Identify and Log Hazards
2. Assess and control Risk
3. Operate
4. Monitor and Log events
5. Review
6. Decommission

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Hazard Management

• Risk Matrix
• Reduce severity
• Reduce likelihood

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Hazard Management

• Mitigation for a Radiation Hazard
• Shielded enclosure with access via locked
  labyrinths
• 2.   Captive Permit key allowing access or beam
  operation
• 3.   A personnel safety system with the following
  features
• Micro-switches on doors as interlocks
• Search required prior to operation
• Audible Warnings
• Annunciator indicating vault status
• Blue lights in vault when access is not allowed
• Signs in vault indicating danger

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Access Zones
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Daresbury

• Hardware

ESRF
DIAMOND
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Hardware

• PLC verses Hardware
• Simple failure modes
• Established system based on DL SRS system
• User confidence in system
• Easier to maintain over a 30 year life
• Many of the advantages of a PLC are not
  requirements of high integrity system
• Configurability
• Upgradeability
• Ease of change

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Hardware

• Dual guard rail interlock system
• Based on Relays
• Redundant
• Diverse
• Interfaced to VME/EPICS via a G64 adaptor
• PPC VME processor to readout module status

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Hardware Dual Guard Rail System
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Hardware SRS Safety Module
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Hardware SRS Backplane
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Hardware VME to G64 adaptor (prototype)
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Test strategy
Markov model of dual guard rail System
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Test Strategy

• Modules Test
• Crate test
• System test
• On line test

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EPICS

• 1. Each PSS rack is an IOC
• 2. Develop device driver for VME/G64 and PSS
  modules This gives access to the PSS status and
  allows the modules to be RESET

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EPICS

• 3. VxWorks applications to check guard line
  operations and test routines - detect faults as
  they develop and help to prevent double faults
• 4. Scripts to sequence resets as part of the
  search
• 5. EDM extension to show logic process
  graphically and to allow resets

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EPICS Typical Reset Window
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Additional safety measures

• Local Rules
• Formal Analysis (Fault Tree analysis)
• Change control
• Safety committee