Module 6: Using Electronic Dosimeters to Monitor Neutron Radiation Dose

Using Electronic Dosimeters to Monitor Neutron Radiation Dose

ACADs (08-006) Covered

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Supporting Material

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Module 6: Using Electronic Dosimeters to Monitor Neutron Radiation Dose

Table of Contents:

Resources Key...... 2

Module Readings and Homework...... 2 Primary Scenario “Dose monitoring during repair of containment coolers during full power operation”...... 2 Transfer Scenario “Dose monitoring during research activity using neutron beam”...... 2

Module Assessment Items...... 3 Primary Scenario “Dose monitoring during repair of containment coolers during full power operation”...... 3

ACAD References...... 6

A Product of DOL Grant # HG-15355-06-60 Page 2 RPT 223 Instructional Resources

Resources Key

This refers This reference: to: ACAD National Academy for Nuclear Training, Uniform Curriculum Guide for Nuclear Power Plant Technician, Maintenance, and Nonlicensed Operations Personnel Associate Degree Programs, ACAD 08-006. DOE-SG Office of Environmental, Safety and Health: Radiological Control Technician Training Site Academic Training Study Guide Phase I, Project Number TRNG-0003

Available at: http://nsedu.rnet.missouri.edu/docshare/. File is located under the Docs/General Curriculum/DOE materials folder. G. Gollnick, D. (2006). Basic Radiation Protection Technology, 5 th Ed. Pacific Radiation Corporation, Altadena, CA.

Module Readings and Homework

Primary Scenario “Dose monitoring during repair of containment coolers during full power operation” Core Concept: Properties of neutron-sensitive electronic dosimeters Homework (end of chapter) Readings Calculation Items Non-calculation Items (none)

Transfer Scenario “Dose monitoring during research activity using neutron beam” Refer to readings and homework for primary scenario above.

RPT 223 Instructional Resources

Module Assessment Items Note: If instructors wish to increase the difficulty of any item, then we suggest you use it as the basis for an in-class discussion, and / or require students to write an explanation for why a particular choice is correct.

Primary Scenario “Dose monitoring during repair of containment coolers during full power operation”

1. What is the difference between a neutron sensitive electronic dosimeter (ED) and one that is not? Select ALL that apply. a. They are the same, except for the software algorithm that separates the gamma dose from the neutron dose automatically. b. Neutron sensitive dosimeters must incorporate a material that has a high probability for neutron interactions. (Correct) c. The neutron dosimeter must have some capability for determining whether the neutrons are fast or thermal. (Correct) d. Both the regular ED and the neutron sensitive ED will always have some sensitivity for gamma-rays that affects the measurement. (Correct)

2. You are being asked to specify the dosimetry needed for two evolutions in containment: one when the reactor is at power and entry is required in preparation for an outage and a second immediately after shutdown as the plant goes into an outage. Which statements are correct concerning the required dosimetry? Select ALL that apply. a. Neutron sensitive primary dosimetry and secondary electronic dosimeters are needed for both evolutions. b. Neutron sensitive primary dosimetry is required when neutrons are present in containment, but not a neutron sensitive ED. c. Since neutrons are present in containment immediately following shutdown, both neutron sensitive primary and secondary dosimetry are required. d. Both neutron sensitive primary and secondary dosimetry are required during operation, but not during shutdown. (Correct)

Researchers at a research reactor are conducting new experiments on a thermal neutron radiography facility. Doses in the area will include thermal neutrons and gamma-rays. As the assigned Radiation Protection Technician for this research, answer questions 3 through 6: RPT 223 Instructor’s Guide The Curators of the University of Missouri Copyright © 2008-2009

3. Which of the of the following possible dosimeter elements should be included in a multi-element dosimeter which could be used for measuring thermal neutron dose around the radiography facility? Select ALL that apply a. 6LiF based TLD (T) b. OSLD with 6Li added (T) c. 7LiF based TLD (F) d. Track etch dosimeter (F) e. Neutron sensitive ED (T) f. Albedo dosimeter (F)

4. With respect to this neutron dosimetry requirement, which of the following processes were necessary your decision. Select all that apply: a. The energy of the neutrons is a factor (T) b. Thermal neutron sensitivity of the dosimeter is a factor (T) c. Thermalization or slowing down of neutrons is necessary (F) d. Neutrons creating ion recoils is necessary (F) e. A high thermal neutron interaction rate is necessary (T) f. Very low gamma-ray sensitivity is necessary (F).

5. Which of these dosimeter elements would also measure the gamma dose? Select ALL that apply a. 6LiF based TLD (T) b. OSLD with 6Li added (T) c. 7LiF based TLD (T). d. Track etch dosimeter (F) e. Neutron sensitive ED (T) f. Albedo dosimeter (T)

6. How is the gamma dose measurement separated from the neutron dose measurement if a dosimeter element is sensitive to both types of radiation? Select all that apply. a. Paired elements are used, one sensitive to both neutrons and gamma-rays and one sensitive only to neutrons, and the difference gives the gamma-ray dose. (F) b. Paired elements are used, one sensitive to both neutrons and gamma-rays and one sensitive only to gamma-rays, and the difference gives the neutron dose. (T)

RPT 223 Instructional Resources

c. All of the dosimeter elements respond uniquely to neutron dose and gamma-ray dose and the signals coming from each type of radiation is proportional to each dose. (F) d. Paired elements are used, one sensitive to only neutrons and one sensitive to only gamma-rays, and each are read separately to get respective doses. (F)

ACAD References ACAD 3.2.3 RADIOLOGICAL SURVEY AND ANALYSIS INSTRUMENTS  Explain the principles of operation of area radiation monitoring systems 3.3.6 EXTERNAL DOSIMETRY  Describe the principles of operation and characteristics of the types of dosimetry used at the plant (thermo luminescent dosimeters, film badge, alarming dosimeters, pocket ion chamber, teledosimetry, optical-luminescent dosimeters) including: – Radiofrequency interference