ELECTRICAL SAFETY FOR RADIOLOGICAL CONTROL TECHNICIANS

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ELECTRICAL SAFETYFOR RADIOLOGICAL CONTROL
TECHNICIANS
EFCOG Electrical Safety Task Group Module 7
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ELECTRICAL SAFETY FOR RCTS
Batteries Stored on shelves Unprotected with easy
access
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ELECTRICAL SAFETY FOR RCTS
Exposed Electrical above bleed valves
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ELECTRICAL SAFETY FOR RCTS
Shock or Arc Flash Hazard Exposed to operate
Switch
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Idaho National Laboratory, Radioactive Waste
Management Complex
ELECTRICAL SAFETY FOR RCTS

• On May 10, 2006 an RCT reported feeling an
  electrical shock on his bare right forearm as he
  was removing the electrical cord plug of a
  Continuous Air Monitor (CAM) vacuum pump from
  around the side and back of an Uninterruptible
  Power Supply (UPS). He felt what he considered to
  be an electrical shock when his forearm came into
  contact with the outside case of the UPS as he
  removed the 110 volt plug from the receptacle
  located on the back of the UPS.

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RCT RECEIVES SHOCK WHILE STARTING A CAM VACUUM
PUMP

• The RCT inadvertently brushed his right outer
  forearm against the exposed 110 volt electrical
  components.  As a result, he received a mild
  electrical shock since he was grounded by the
  beta CAM metal rack.  The RCT reported the
  incident to his manager and stated that he felt
  fine. The RCT was escorted to the First Aid
  stations for observation and was then escorted to
  the Hanford Environmental Health Foundation
  (HEHF) for further evaluation.

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Unexpected Electrical Hazards
RCT RECEIVES SHOCK WHILE STARTING A CAM VACUUM
PUMP
On 08/23/95, a Radiological Controls Technician
(RCT) at T Plant received a mild shock when his
hand brushed energized contacts inside an
instrument cabinet.  He was starting a vacuum
pump for a continuous air monitor (CAM) and
reached into the cabinet to verify pump
operation.  He was not injured.
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Burned Wire on PCM-2 Personnel Contamination
Monitor Causes Facility Evacuation

• On 12/29/05 after exiting the 105KE Basin and
  proceeding to the PCM-2, an operator observed
  that the displays on the monitor were not working
  and heavy smoke was coming out of the top of the
  unit. The facility was evacuated and the monitor
  was unplugged. When Hanford Fire Department (HFD)
  personnel arrived they found no fire or smoke
  coming from the monitor.

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Burned Wire on PCM-2 Personnel Contamination
Monitor Causes Facility Evacuation

• An Eberline Personnel Contamination Monitor
  (PCM-2) at the 105KE facility experienced a
  "loose wire" that caused an electrical short. The
  short caused wiring insulation to burn, which
  cause heavy smoke to emanate from the top of the
  instrument, leading to a facility evacuation.

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Burned Wire on PCM-2 Personnel Contamination
Monitor Causes Facility Evacuation

• Instrument Technicians found burned insulation on
  a six-foot section of wire associated with a
  photocell on the foot pad. The wire had loosened
  and sagged over time, eventually pulling free and
  shorting out. The smoke was preceded by an
  intermittent failure of the PCM-2 to count
  continuously when the worker switched from the
  front count to the back count.

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Burned Wire on PCM-2 Personnel Contamination
Monitor Causes Facility Evacuation

• Inspection of other units in the facility found
  loose/sagging wires on two of three similar
  monitors, which were subsequently repaired.
• Eberline, the manufacturer, is aware of this
  issue and has made available a harness kit for
  these instruments that will reroute and properly
  secure the wires away from the foot area of the
  PCM-2. Owners of PCM-2 Personnel Contamination
  Monitors should check their units for similar
  problems.

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Unexpected Electrical Hazards
Unguarded Temporary Light Exposes energized parts.
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Working on or NearExposed Energized Parts

• Unqualified Persons, Safe Approach Distance
• Unqualified persons are safe when they maintain a
  distance from the exposed energized conductors or
  circuit parts.
• The safe approach distance is the Limited
  Approach Boundary.

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LAB 50 to 300 V Exposed Movable Parts 10 feet
LAB 50 to 300 V Exposed Fixed Parts 3.5 feet
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NFPA 70E Standard for Electrical Safety
Requirements for Employee WorkplacesTable
2-1.3.4 Approach Boundaries to Live Parts for
Shock Protection. (All dimensions are distance
from live part to employee.) 
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NFPA 70E Standard for Electrical Safety
Requirements for Employee WorkplacesTable
2-1.3.4 Approach Boundaries to Live Parts for
Shock Protection. (All dimensions are distance
from live part to employee.) 
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Working on or NearExposed Energized Parts

• The Flash Protection Boundary is 4 ft. for
  systems 600 volts and below unless calculated
  otherwise under engineering supervision.

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Temperature And Heat Data

• Curable burn temperature (1/10sec)
  145 F
• Cell death temperature (1/10 sec) 205 F
• Temperature at arc terminals
  35,000 F
• Temperature of suns surface
  9,000 F
• Temperature of burning clothing
  1,400 F
• Clothing ignition temperature 700 to
  1,400 F
• Temperature of metal droplets 1,800 F

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Working on or NearExposed Energized Parts

• Unqualified Persons, Safe Approach Distance
• Unqualified persons must not cross the Flash
  Protection Boundary unless they are wearing the
  appropriate PPE and under the supervision of a
  qualified person.

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CPP 1982 Roll in Breaker
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CPP 1982 Roll in Breaker
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CPP 1982 Roll in Breaker
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Consequences of an Arc-Flash Incident
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Consequences of an Arc-Flash Incident
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Brookhaven 4/2006 Arc-Flash Incident
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Brookhaven 4/2006 Arc-Flash Incident
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Brookhaven 4/2006 Arc-Flash Incident
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Brookhaven 4/2006 Arc-Flash Incident
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Arc Flash Protection Boundary
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Common Electrical Exposures for RCTs
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2100 Volts DC
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Eberline CAM
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Canberra CAM
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Electricity is a part of our daily lives, harness
its power but recognize the hazards.