response checks of portable radiation detection instruments

Response Checks of PortableRadiation Detection Instruments

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

“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 Source Rod Assembly

Cs-137130 mCi400 Ci

Shepherd Shielded Calibration Range Assembly

Shepherd Attenuator Assembly

Shepherd 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

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

Observation Window

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

Alpha Survey Instrument

Neutron Survey Instrument

Response Check ofNeutron Instruments

Set up the Instrument Scale Instrument Over Neutron Source Check Other Scales/Decades with

Pulse Generator Compare Results with Response

Log Document Results

Frisker

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

Tritium in Air Monitor

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

Prevent Errors -Reduce Contamination