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Response Checks of Portable Radiation Detection Instruments. HPT 001.306. Enabling Objectives. Name Instrument Control Procedure State Calibration Organization State Frequency of Response Checks Identify Response Check Equipment Identify Shepherd Components. Enabling Objectives.
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Response Checks of PortableRadiation Detection Instruments HPT 001.306
Enabling Objectives • Name Instrument Control Procedure • State Calibration Organization • State Frequency of Response Checks • Identify Response Check Equipment • Identify Shepherd Components
Enabling Objectives • State Isotopes & Activity for Shepherd Sources • Identify Response Window Criteria • Identify Instruments Response Checked with Plutonium • State Purpose of Scintrex Model 309A
Instrumentation Controls • TVAN RCDP-8, “Radiological Instrument/ Equipment Controls”
Instrument Calibration • Portable Radiation Detection Instruments Calibrated by:Environmental RadiologicalMonitoring & Instrumentation (ERM&I)Western Area Radiological Laboratory,(WARL) Muscle Shoals, AL
Response Check Frequency • Teletector & RSO-7 Daily • Beta-Gamma Instruments Weekly • Alpha & Beta Friskers Weekly • Neutron Dose Instruments Weekly • On-Site REP Instruments Weekly • Electronic Dosimeters Quarterly
Response Checks ofBeta-Gamma Dose Instruments • Shepherd Model 89 Irradiator- Source Rod Assembly- Shielded Calibration Range Assembly- Attenuator Assembly- Table Assembly
Shepherd Precautions • Plugs in Unused Access Ports • Hands & Fingers Clear of Door • Never Lubricate Source Rod • Don’t Twist Attenuator Handles • Move Table Slowly • Utilize Survey Meter
Shepherd Performance Checks • Test the Interlock System- Attempt to Raise Source or Open Door with Power Off- Attempt to Raise Source with Door Open- Attempt to Open Door with Source Raised
Establishing Response Windows • Expose at Least Four Instruments • Exposure Values Near Midscale • Set Window for Each Scale
Response Window Criteria • Arithmetic Mean of all Instruments • Calculate Highest Percent Difference • Calculate Lowest Percent Difference • Discard Highest or Lowest Percent Difference if Exceed 10 Percent • Response Window = Mean ± 20 % • Expressed as Range
Instrument Pre-Operational Checks • Inspect for Damage • Inspect Switches, Alarms, Controls • Inspect Cables & Power Cords • Check Battery Strength • Instrument in Calibration
Performing Response Checks with Shepherd Irradiator • Position Instrument on Guide- Beta Gamma Survey Meter- Teletector- Electronic Dosimeter
Performing Response Checks with Shepherd Irradiator • Position Attenuators and Platform • Close Door • Raise Source to make Exposure • Lower Source to “Off” • Repeat for Each Scale • Document Results
Response Check of AlphaSurvey Instruments • Alpha Sources, ie Pu-239 • Inspect Mylar Windows • Perform Light Test • Expose Detector • Compare Results with Response Log • Check Each Scale or Decade • Document Results
Response Check ofNeutron Instruments • Set up the Instrument Scale • Instrument Over Neutron Source • Check Other Scales/Decades withPulse Generator • Compare Results with Response Log • Document Results
Response Check ofFriskers • Sources Identified in Response Log • Set Frisker to Appropriate Range/Scale • Position Probe over Source • Repeat for Other Scales • Compare Results with Response Log • Document Results
Response Check ofScintrex Model 309A • Inspect Filter Paper • Ensure Battery >3.0 volts • Set Function Switch to ‘Display On’ • Press ‘Test’ Button • Observe Display < 50
Response Check ofScintrex Model 309A • Position Gamma Source on Right Side • Wait 1-2 Minutes • Observe Reading Between 8 & 24 • Depress ‘Test’ Button • Document Results
Summary • Instrument Calibration Critical • Response Checks Confirm Operation • Shepherd Model 89 Irradiator • Other Response Checks:- Alpha Survey Instruments- Neutron Instruments- Friskers- Tritium-in-Air