NUCLEAR TRAINING - Go Nukegonuke.org/wp-content/toolkits/Radiation Protection/chscc/some...

I. PROGRAM: Radiological Protection Technician Initial Training

II. COURSE: Specialty Area Training – Instrumentation and Respiratory Protection

III. TITLE: Response Checks of Portable Radiation Detection Instruments

IV. LENGTH OF LESSON: 16 hours

V. TRAINING OBJECTIVES

A. Terminal Objective

Upon completion of this module, participants will demonstrate knowledge of the procedures used for performing response checks on portable radiation detection instrumentation. A score of > 80% must be achieved on a written examination.

B. Enabling Objectives

Standards and conditions apply to all enabling objectives. They include the training participant’s ability to utilize, under the examination ground rules (i.e. without the use of training materials or outside assistance), the information presented in this lesson plan.

1. Name the procedure that establishes controls for calibration, testing, maintenance, and repair of radiation detection instruments and equipment.

2. State the organization responsible for the calibration of portable radiation protection instrumentation.

3. Identify the equipment used to response check most beta-gamma detection instruments.

4. Identify the 4 components (assemblies) of the Shepherd Model 89 Irradiator.

5. State the isotopes used and the strength or activity of the two sources used in the Shepherd Model 89.

6. Identify the criteria for setting response windows for the Shepherd Model 89.

7. Identify the types of instruments for which plutonium is used to check the instrument response.

8. State the purpose of the Scintrex Model 309A Monitor.

VI. TRAINING AIDS

A. Whiteboard with markers.B. Projector and ScreenC. Power Point Presentation of Key PointsD. Laser Pointer (optional)E. Instruments for demonstration, such as RSO-50, Teletector, or Scintex 309A.

VII. TRAINING MATERIALS :

A. Appendices

1. Handouts

a. HO-01 – Enabling Objectives

B. Attachments

1. Power Point Transparencies, Slide show located at P\Training\Technical Programs and Services\Radcon\Initial Program\Lesson Plan Library\Library\ HPT001.306, Response Checks of Portable Radiation Detection Instruments\HPT001.306.ppt.

2. OE12721, “Interlock Test on 400 Curie Source Calibrator Failed its Operability Test Prior to Use,” Three Mile Island Unit 1, August 20, 2001.file://C:\WINDOWS\Temp\InpoReader572782.htm.

3. OE14896, “Calibration Irradiator Safety Interlock Malfunction,” Oconee Nuclear Site Unit 1, 2, and 3, October 3, 2002.file://C:\WINDOWS\Temp\InpoReader174682.htm.

4. OE16732, “Shepherd Calibrator Source Could be Lifted with the Calibrator Turned Off and the Key Removed Due to Wear of the Door Interlock,” McGuire Unit 1 and 2, July 15, 2003.file://C:\WINDOWS\Temp\InpoReader724350.htm.

VIII. REFERENCES:

A. ACAD 93-008, “Guidelines for Training and Qualification of Radiological Protection Technicians,” National Academy For Nuclear Training, August 1993.

B. Code of Federal Regulations, Title 10, Part 50, “Domestic Licensing of Production and Utilization Facilities,” U.S. Government Printing Office, Washington, 2003.

C. Principles of Radiation Protection, Morgan and Turner, John Wylie & Sons, Inc., New York, 1967.

D. Introduction to Health Physics, Second Edition, Herman Cember, Pergamon Press, New York, 1985.

E. Radiological Instrumentation/Equipment Controls,” Revision 1, September 4, 1999.

F. Watts Bar Nuclear Plant RCI-109, “Radiological Control Portable Instrumentation,” Revision 13, June 23, 2004.

G. Browns Ferry Nuclear Plant RCI-11.1, “Radiological Protection Instrument Program Implementation,” Revision 59, July 20, 2004.

H. Sequoyah Nuclear Plant RCI-5, “Radiological Control Instrumentation Program,” Revision 41, August 25, 2004.

I. http://www.sartrex.com/HealthPhysics/309ARev1Nov142002.pdf

J. Title 10, Code of Federal Regulation, Part 20, “Standards for Protection Against Radiation,” January 1, 2003.

http://www.sartrex.com/HealthPhysics/309ARev1Nov142002.pdf

HPT001.306Revision 3Page 4 of 24

IX INTRODUCTION:

Human senses do not respond to ionizing radiation, so some form of instrumentation must be used for the detection and measurement of radiation. Qualitative as well as quantitative measurements are required, because the potential impacts are dependent on both the type of radiation as well as its quantity. Even so, the most carefully made measurements may be seriously in error if the instrument is not properly calibrated, adjusted, and serviced. Instrument calibration must be performed often enough to prevent errors in measurements with an otherwise operable instrument. The instruments are calibrated by exposing the instrument in a known radiation field, and then comparing the meter reading to the known field. In most cases, the instrument is then adjusted to read the radiation level equivalent to that of the known field, however, is some cases, a calibration curve may be plotted so that the meter reading can be adjusted mathematically to produce the desired level. For the majority of portable radiation protection instruments, this calibration is performed every 6 months.

In addition to the calibration of the instruments, the instruments are checked routinely for overall operability. These checks include both response checks and source checks. The frequency of these checks depends on the type instrument and the specific requirements of each individual plant. This lesson will address the general procedures for performing these checks.

INSTRUCTOR NOTE

Note to Instructor:In Lesson Plan HPT001.037, “Radiological Environmental Monitoring Program,” it was recommended that a field trip to the Western Area Radiological Laboratory in Muscle Shoals, AL, be conducted in conjunction with that lesson. The Laboratory conducts the Radiological Environmental Monitoring Program for nuclear power facilities and includes a Calibration Facility where the portable radiation monitoring instruments are calibrated for all nuclear power plants. A trip to this laboratory would include a visit to both facilities.Contact the Manager, Environmental Radiological Monitoring and Instrumentation at 386-2536 to coordinate the trip.

A trip to the plant instrumentation laboratory to observe the operation of the Shepherd Irradiator and the performance of response checks would also be appropriate. Coordinate with the Instrumentation supervisor.


X. LESSON BODY INSTRUCTOR NOTES

A. Radiological Instrumentation/Equipment Controls TP-1, 2, & 3

1. 10 CFR 20.1501 requires licensees to ensure that instruments and equipment used for quantitative radiation measurements (e.g., dose rate and effluent monitoring) are calibrated periodically for the radiation measured.

2. procedure established controls for calibration, testing, maintenance, and repair of radiological instrumentation and equipment which are used to implement this requirement.

TP-4

Objective 1

The procedure provides controls for the procurement, calibration and maintenance, response and source check, and inventory and control of the instrumentation.

B. Instrument calibration

1. Portable radiation detection instruments used at nuclear power plants are calibrated by ???

Objective 2

TP-52. Nonportable instrumentation (laboratory counter scalers,

laundry monitors, bag monitors, portal monitors, whole body friskers, whole body counters, respiratory fit equipment, portable CAMS, portable air samplers, etc.) are normally calibrated and maintained by site RADCON or using appropriate maintenance and calibration criteria supplied by site RADCON.

3. Standards (radioactive sources, instruments, or devices) used to calibrate radiological instruments must have documentation that establishes traceability to the National Institute of Standards and Technology (NIST) in accordance with RCDP-8, and the Radiological Control and Radiological Material Shipment Augmented Quality Assurance Program (SPP-5.9).

4. Radiological instrumentation shall be calibrated at the following frequencies (or more frequently if job conditions warrant):

a. Semi-annually for portable radiation, contamination, and air sample instrumentation (examples: RO2A, RSO50, Surveyor 50, Ludlum 177, HV-1, AVS-28A,



BC-4, SAC-4, etc.).

b. Annually for electronic dosimetry.

c. Semi-annually for whole body friskers, portal monitors, bag monitors, and tool monitors (examples: LB5100, BWM-10, Gamma 60, PM-7, PCM, TCM-2, Mini EDGAR, etc.).

d. Instruments may be calibrated less frequently when reserved for special purposes and conspicuously tagged (e.g., “For Training Only”).

C. Response checks on instruments

1. Response checks are checks that verify that an instrument will respond within set limits on each normally used scale or decade to a radiation field of reproducible intensity and geometry.

2. Site RADCON establishes procedures for performance of checks on instruments to ensure that the operability and accuracy of instruments are maintained between calibrations. Instruments are response and/or source checked at a frequency which is sufficient to demonstrate proper instrument operation.

3. The frequency at which the response checks are performed varies with the instrument type and use. There may be small variations among the plants, but generally the following schedule applies to each site:

TP-6

a. High level instruments using multiple detectors, like the Teletector and RO-7, are response checked daily.

b. Beta-Gamma and neutron radiation dose rate instruments like the PNR-4, Ludlum 12-4, R02A, RSA-5, and RSO-50 are response checked weekly.

c. Alpha and beta contamination count rate survey instruments like the Ludlum 177 frisker and the Bicron Surveyor M-X are response checked weekly.



d. Instruments set aside for use in a radiological emergency are typically response checked weekly, although some of the instruments that are stored off-site in places like a local hospital may only be checked monthly or quarterly.

e. Electronic dosimeters are response checked quarterly.

f. In addition to these routine response checks, checks may also be performed when placing an instrument in or removing an instrument from in-service status or any time the operation of the operation or response of an instrument is in question.

4. Before performing a response check on any instrument, the instrument must be turned on and allowed to warm up for at least one minute.

5. Response checks using the Shepherd Model 89 Irradiator.

Response checks for most beta-gamma survey instruments, including Teletectors and RO7s, and electronic dosimeters are performed on the Shepherd Model 89 irradiator.

Objective 3

a. The Shepherd Model 89 source consists of four subassemblies. These include the source rod assembly, the shielded calibration range assembly, the attenuator assembly, and the table assembly.

Objective 4

TP-7

(1) Source Rod Assembly - The source rod assembly consists of two separately encapsulated Cs137 sources of 130 mCi and 400 Ci mounted on a single operating rod. The source mounting configuration on the operating rod is such that only one source may be exposed at any given time. The selected source is moved from the off (housed) position to the exposed (beam port) position by operation of the manual positioning lever. Mechanical stops on the source tower allow for precise positioning of the source lever. Additionally, lights are provided on then top of the source rod assembly to indicate which source is exposed in the beam port.

Objective 5

TP-8



(2) Shielded Calibration Range Assembly - The shielded calibration range assembly consists of a shielded door integrated with an electro-mechanical interlock system, remote detector access ports, a lead glass viewing window, and an irradiation volume.

TP-9

(3) Attenuator Assembly - The attenuator assembly consists of four different thicknesses of tungsten alloy which, when placed over the beam port, provide the various intensities of gamma radiation required for response checking an instrument.

TP-10

(4) Table Assembly - The table assembly consists of a platform, adjustable through two of three mutually perpendicular axes, coupled to a mechanical position indicator. This assembly provides detector positioning in precise orientation with the gamma field presented by the source.

TP-11

b. The following precautions should be observed while using the Shepherd Model 89 Irradiator:

TP-12

(1) Ensure access ports are plugged when not in use. Error Prevention Tools Two Minute Rule

(2) Ensure hands and fingers are clear prior to closing exposure chamber door.

Follow proceduresSelf-Checking: S top

(3) Never lubricate the source rod. If at any time the operation of the source rod becomes difficult, the Shepherd Model 89 source shall be placed out of service and the appropriate RADCON shift supervisor notified.

T hink A ct R eviewHave a Questioning Attitude.

(4) Do not attempt to twist or turn the attenuator operating handles. Such action may damage the attenuator.

(5) When adjusting the position of the table, turn the table crank slowly until the edge of the table is in contact with the exposure chamber wall. Ensure that the table position indicator is as indicated for the appropriate instrument.



(6) Utilize an ion chamber survey meter, as applicable, during operation of the Shepard Model 89 to verify acceptable working area dose rates and that the source has been returned to a safe position.

ALARA Operator should ensure that he/she is not in the radiation field when instruments are inserted through the ports for exposure.

c. Performance of the Shepherd Model 89 Calibrator Interlock, Table Position, and Light Check (usually performed weekly). The procedures are generic and may vary slightly from site to site.

TP-13

Review OEs 12721, 14896, and 16732 (Attachments 2, 3, & 4). In all three events, the interlock failed so that

(1) Perform the following with the power OFF: the source could be lifted either with the door open

(a) Unlock and remove the source rod locking bar.

or with the switch turned “OFF.” All of these malfunctions had the

(b) Depress the button beside the door latch and attempt to open the door.

capability to produce an exposure to personnel. In each case, the cause

(c) Depress the button on the tower and attempt to raise the source rod.

of the malfunction was attributed to the lack of adequate preventive

(d) If the door opens, or the source rod raises, then place the calibrator out of service and notify the appropriate RADCON Shift Supervisor.

maintenance. This emphasizes the need to be diligent in performing the interlock checks as required, taking care in

(2) Perform the following with the power ON: the operation of the equipment to reduce

(a) Ensure that the attenuators are pushed in. wear and tear, and in performing regular

(b) Open the chamber door and then slowly attempt to raise the source rod to the 130 mCi slot.

preventive maintenance.

1) If the rod goes above the interlock position, then the green light will go off.



2) Immediately place the source rod back into the off position. Lock the calibrator, place it out of service, and notify the appropriate RADCON Shift Supervisor.

(c) Raise the source rod to the 130 mCi position and slowly attempt to open the chamber door.

1) If the door opens, then immediately close it.

2) Lock the calibrator, place it out of service, and notify the appropriate RADCON Shift Supervisor.

(d) Repeat steps (b) and (c) for the 400 Ci source.

d. When performing a response check, the reading of the instrument on each scale must fall within a predetermined range of values. These ranges (windows) are determined in the following manner:

TP-14

(1) Response windows should be set by exposing at least four calibrated instruments of the same type to the radiation check source in a reproducible configuration. These instruments should not have been used for surveys prior to being used to set the windows.

Combining response check windows for similar types of instruments is acceptable provided detector-to-source geometry is identical.

(2) If fewer than four instruments of the same type are available at the same time, measurements may be made over a time span of up to 90 days. If the inventory contains less than four instruments, the total number available can be used to determine the window.

(3) The exposure values delivered should generally



register a response near midscale for linear instrument meters and near the midpoint of the needle movement for logarithmic and quasi-logarithmic meters.

(4) After the source-to-detector distance has been established for one range on an instrument, it should be held constant for each range on the same survey instrument. When possible, use the same distance setting for all types of instruments.

(5) A response window should be set for all instrument scales unless the instrument ranges exceed the source device capabilities.

(6) Criteria for setting the windows. Objective 6

(a) The response window is established utilizing the arithmetic mean of all instrument readings taken.

TP-15

(b) After calculation of the arithmetic mean, the percent difference shall be calculated between the arithmetic mean (XA) and the highest (XH) and lowest (XL) readings.

1) Highest percent difference (H%D)

H%D = (XH – XA) x 100 XA

Use Self-Checking and Peer-Checking when entering data or performing calculations.

2) Lowest percent difference (L%D)

L%D = (XL – XA) x 100 XA

(c) If the percent difference (% Diff.) is greater than 10 percent for any instrument, the reading (XH or XL) shall not be used in calculating the arithmetic mean (XA). If two of the differences exceed 10 percent, all instrument readings shall be considered invalid.

(d) If the value (XH or XL) must be removed



from the data set, a new mean and a second percent difference must be calculated between the new arithmetic mean and the lowest and highest values after (XH or XL) has been removed from the data set. If either of the percent differences exceed 10 percent, all instrument readings shall be considered invalid.

(e) If all instrument readings are determined invalid, the calibration facility supervisor should be informed. Establishment of the response window shall then be conducted with a new set of calibrated instruments or the same set recalibrated.

(f) The response window shall be established using the arithmetic mean of all the valid instrument readings taken, ±20 percent and rounded to the nearest readable scale markings, not to exceed 25 percent above or below the arithmetic mean.

(g) The response window shall be expressed as a range of values, e.g., between A and B where A and B are numerical values and A is less than B.

(7) Response windows shall be reestablished at least biennially or every 0.07 half-life of the radiation check source, whichever is sooner.

(8) The process of setting response windows is documented using the following information for each response window.

(a) The date of setting the response window;

(b) The name of the person setting the response window;

(c) A list of the instruments used by tag number;



(d) A description of the instrument/source configuration;

(e) The reading of each instrument;

(f) The response window;

(g) The response window expiration date.

e. The following pre-operational checks are performed on each instrument prior to the performance of the response check:

TP-16

(1) Inspect for physical damage which may impair operation. This includes an inspection of the beta window, if applicable.

Incorporate intoTwo-Minute Rule

Utilize:

(2) Inspect all switches, alarms, or controls for proper functionality.

Self-CheckingPeer-Checking

(3) Ensure all cables and power cords are in acceptable condition.

(4) Ensure sufficient battery strength.

(5) Ensure the instrument is within calibration period and response checked (if applicable).

f. Performing the response checks with the Shepherd Model 89 Irradiator.

PERFORMANCE OF RESPONSE CHECKS REQUIRES THE USEOF EQUIPMENT THAT GENERATES HIGH FIELDS OFRADIATION. BY-PASSING THE INTERLOCKS ON THESHEPHERD CALIBRATOR IS PROHIBITED.



(1) Unlock the chamber door and the source rod locking bar and turn on the AC power.

TP-17 & 18

(2) A series of positioning guides templates has been constructed to aid in ensuring that each instrument is positioned properly on the irradiator platform. Select the proper template for the instrument or device to be checked and mount the instrument in the guide and the guide on the platform. Ensure the instrument is ‘on’ and that it is set to the desired scale.

Error Prevention Tools Two Minute RuleFollow proceduresSelf-Checking: S top T hink A ct R eviewHave a Questioning Attitude.

(3) If a Teletector or RO-7 type instrument is being checked, the detector must be inserted into the chamber through the one of the ports in the door and placed on the appropriate template.

TP-19ALARA Operator should ensure that he/she is not in the radiation field when instruments are inserted through the ports for exposure.

(4) For electronic dosimeters, place the dosimeters to be checked into the appropriate template and place the template on to the platform.

TP-20

(5) Position the attenuators and platform in accordance with the reference window data sheets.

TP-21

(6) If an integrated dose measurement is to be made, reset the timer to ‘zero.’

(7) Press the source release button and simultaneously raise the source rod assembly to the desired source position.

(8) Observe the instrument indication and compare the response with the response window data sheet. Document the results.

TP-22

(9) If the response falls within the response window, attach a response check sticker to the instrument or update the current sticker, as appropriate.



(10) If the response Does Not fall within the response window, tag the instrument out of service and set it aside for repair.

Most response check failures are the result of older instruments which are becoming more unstable. Another mode

(11) Return the source rod assembly to the ‘off’ position. Ensure the source operating rod is completely down and the green safety light is energized.

of failure occurs with instruments that have 2 detectors, like the Teletector, when one detector response will

(12) Repeat the above steps until all scales have been checked, as applicable.

fall outside the window and other will fall within the window.

(13) When completed, remove the instrument or detector(s) from the chamber, close the chamber door, and turn off the AC power. Insert and lock the source locking bar.

Focus on the Four:Equipment Reliability!

As primary users of this (14) Document the results on the appropriate response

check form, instrument sticker, and/or computer entry, in accordance with plant specific procedures.

equipment, we must do everything we can to maintain the reliability of the instruments.

6. Response check of Alpha Survey Instruments. This includes:1. Careful handling – no

a. Instruments with logarithmic scales or auto-ranging capability require one verified point per decade of meter response.

rough treatment or banging around.2. Make slow, deliberate actions when changing settings.

b. Response checks of alpha survey instruments are typically performed by the use of a set of alpha sources, such as plutonium (Pu-239). The set will normally include a range of source strengths capable of producing a response on each of the scales or decades of the instrument.

3. Report problems immediately.4. Ask students for other suggestions.

Objective 7

TP-23c. Performing the response check.

(1) Check the Mylar window for holes or tears.

(a) First, look for any obvious holes or tears.



(b) If the detector is a scintillator, hold the probe up to a light. Up-scale deflection of the meter may indicate small pinhole light leaks. If up-scale deflection is observed, place the instrument out-of-service.

(c) If the Bicron M-X has a light leak, the instrument will not respond. When checking the Bicron M-X for light leaks, an alpha source must be placed on the detector. If the detector responds as expected, then no light leaks exist. If there is no response, tag the instrument out-of-service.

(2) Place the probe over the respective sources and ensure response is within the established window(s). Repeat for each scale or decade.

TP-24

(3) Document the results on the appropriate response check form, instrument sticker, and/or computer entry, in accordance with plant specific procedures.

7. Response check of Neutron Survey Instruments. TP-25

a. Instruments with logarithmic scales or auto-ranging capability require one verified point per decade of meter response.

TP-26

b. Place the instrument over the respective source and ensure that the response is within the established window. When the instrument feet are in the designated locations identified on the source, the instrument is in the proper response check position.

c. Use of a Varipulser (Model VP-2E), or similar pulse generator, is required to successfully check each scale or decade on the neutron meter.

(1) Connect the pulse generator to the instrument in accordance with the operational instructions for the instrument.

(2) Compare the survey meter response to the



response window log.

d. Document the results on the appropriate response check form, instrument sticker, and/or computer entry, in accordance with plant specific procedures.

8. Response check of Friskers. TP-27

a. Procedures for performing the response check for Friskers may vary from plant to plant. Refer to plant-specific procedures for sources to be used and instrument scales which must be checked.

TP-28

b. Perform the response check on Friskers using the sources listed on the response window log.

c. Place the Frisker on the appropriate range and position the probe over the source.

d. Repeat for other scales as required by plant-specific procedures.

e. Verify alarm actuation at approximately 100 cpm above average background.

f. For Bicron Surveyor 50 friskers, the following additional requirements and information may apply:

(1) To verify proper operation of the high voltage capability, turn the select knob to the HV setting and ensure that the high voltage reading is within the HV OK range.

(2) These friskers are not equipped with an adjustable alarm.

g. Document the results on the appropriate response check form, instrument sticker, and/or computer entry, in accordance with plant specific procedures.



9. Response check of the Scintrex Model 309A Instrument. TP-29

At the present time TVA is contracted with the Department of Energy (DOE) to produce tritium at Watts Bar Nuclear Plant. As a result of this program, tritium in air is monitored at WBN, both on a routine basis and during response to a radiological emergency at the plant. The instrument used for this monitoring is the Scintrex Model 309A Tritium-in-Air Monitor.

Objective 8

Since BFN and SQN are responders for the WBN Radiological Emergency Plan (REP), they also support the capability to monitor for tritium in air by maintaining the Model 309A monitors in their REP field monitoring vans.

a. The Scintrex permits tritium measurements in the range of 1 to 200,000 µCi/m3 (1.0 E-6 to 0.2 µCi/cc).

b. The pump draws air for tritium analysis through an ion chamber. The ion chamber induces a current which is proportional to the tritium concentration. An electrometer amplifies, filters, and converts the current to a measurable voltage.

c. Precautions and Limitations

(1) Power up the Scintrex in the Display On position using the AC adapter power plug. The Scintrex should be powered up for at least 48 hours before making any measurements.

(2) The electrometer in the Scintrex requires a warm-up period of 15-30 minutes when all power is lost (e.g., dead batteries). For continuous monitoring or long duration activities, consideration should be given to the use of an AC adapter for an uninterrupted power supply.

(3) The Scintrex should remain connected to a 110V AC adapter when not in use to preserve battery power and maintain operational readiness. Expected battery life is 6 ± 2 hours when the pump is on, and 10-20 days when turned off.



(4) When the batteries are depleted to approximately 2.7V, the message Battery Low will be briefly displayed only at the Display On and Pump On positions of the function switch. The monitor will continue to operate properly for approximately 30 minutes after this message is displayed.

(5) The Scintrex should only be used if GM instruments indicate background levels; otherwise, the tritium results will be invalid due to interference from noble gas.

d. Preliminary checks TP-30

(1) Inspect the inlet filter paper. The filter should have no tears or dirt dust buildup. Replace if necessary.

(2) Ensure that the battery voltage is greater than 3.0 volts. The Scintrex must be disconnected from the AC power supply to determine the voltage of the batteries.

(3) Zero set the Scintrex.

e. Performing the response check. TP-31

(1) Ensure that the Function switch is set to Display On and press the Test button. The display will read Gamma Test Setup.

(2) After a short delay, a numerical value and the word Test (e.g.,–25 Test) will be displayed. If the numerical value is ≥50, the unit will alarm until it decreases to <50. The test feature eliminates the gamma compensation chamber, allowing flow through the ion chamber to respond to a gamma check source.

(3) Place the gamma source (approximately 5 µCi Cs-137) in position on the right hand side of the Tritium Monitor.

(4) After 1-2 minutes, the instrument should read between 8 and 24.



(5) Upon satisfactory completion of the response check, depress the Test button. The display will read Return Delay. After a short delay, a measurement value will be displayed. The displayed value (µCi/m3) will stabilize in approximately 1 minute.

(6) Document the results on the appropriate response check form, instrument sticker, and/or computer entry, in accordance with plant specific procedures.


XI. SUMMARY INSTRUCTOR NOTES

The use of measuring equipment is critical in the detection of radiation and radioactivity. Without adequate instrumentation we would not be able to identify the presence of radioactive materials. In order to obtain accurate measurements of the types and quantities of these materials, we must ensure that the instrumentation we are using is operating properly. In addition to calibrations that establish the accuracy of the equipment, regular checks must be performed to verify that the instruments are continuing to perform as intended. One phase in this process is the performance of routine response checks on the instruments in use. This lesson has presented the methodology for performing those response checks, including the use of the Shepherd Model 89 Irradiator in that process. In addition to the Shepherd irradiator, other radiation sources and techniques are used to perform these checks. Alpha detection instruments are checked with such sources as plutonium, while americium-beryllium sources are used for neutron detectors. Other sources prominently used in performing response checks include Co-60, Cs-137 and Tc-99.

Remember to always to employ the Error Prevention Tools. Awareness of these tools can prevent unnecessary radiation exposures or injury and increase equipment reliability by reducing the number of radiation detection instruments that become contaminated. (See TP-33)

TP-32

TP-33


Handout 1

Enabling Objectives

1. Name the procedure that establishes controls for calibration, testing, maintenance, and repair of radiation detection instruments and equipment.

2. State the organization responsible for the calibration of portable radiation protection instrumentation.

3. Identify the equipment used to response check most beta-gamma detection instruments.

4. Identify the 4 components (assemblies) of the Shepherd Model 89 Irradiator.

5. State the isotopes used and the strength or activity of the two sources used in the Shepherd Model 89.

6. Identify the criteria for setting response windows for the Shepherd Model 89.

7. Identify the types of instruments for which plutonium is used to check the instrument response.

8. State the purpose of the Scintrex Model 309A Monitor.

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