Regulatory Guide 4.13

Performance,Testing & Procedural Specifications for Thermoluminescence Dosimetry:Environmental Applications

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Issue date:	07/31/1977
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Revision 1 U.S. NUCLEAR REGULATORY COMMISSION July 1977 REGULATORY GUIDE

OFFICE OF STANDARDS DEVELOPMENT

REGULATORY GUIDE 4.13 PERFORMANCE, TESTING, AND PROCEDURAL SPECIFICATIONS

FOR THERMOLUMINESCENCE DOSIMETRY:

ENVIRONMENTAL APPLICATIONS

A. INTRODUCTION

criteria for TLD systems used for this purpose. It also provides procedures for calibration, field application, I*

Section 20.105, "Permissible levels of radiation in and reporting. It does not apply to TLD systems used unrestricted areas," of 10 CFR Part 20, "Standards for the purpose of determining occupational ex for Protection Against Radiation," provides limits on posure.

levels of radiation in unrestricted areas resulting from

B. DISCUSSION

possession, use, or transfer of NRC-licensed radioac tive material. Section 20.201, "Surveys," of 10 CFR Working Group 9 of the Health Physics Society Part 20 further requires that a licensee conduct sur Standards Committee for American National Stan veys as may be necessary to comply with the regula dards Institute (ANSI) Committee N 13 on Radiation tions of 10 CFR Part 20 including, when appropriate, Protection has prepared a standard that specifies the measurement of levels of radiation. minimum acceptable performance of TLDs used for Paragraph IV.B(2) of Appendix I, "Numerical environmental measurements; outlines methods to Guides for Design Objectives and Limiting Condi test for compliance; and provides procedures for tions for Operation to Meet the Criterion 'As Low As calibration, field application, and reporting. This Is Reasonably Achievable' for Radioactive Material standard was approved by the N13 Committee. It in Light-Water-Cooled Nuclear Power Reactor Ef was subsequently approved and designated N545 fluents," to 10 CFR Part 50, "Licensing of Produc 1975, by ANSI on August 20, 1975.1 tion and Utilization Facilities," requires that

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The specification of performance criteria of ther licensees establish appropriate surveillance and moluminescence dosimetry and the verification of the monitoring programs to provide data on measurable actual performance require appropriate statistical levels of radiation and radioactive materials in the en concepts and techniques. Because wide applicability vironment. is intended, ANSI N545-1975 as well as the provi sions and clarifications given below in the regulatory General Design Criterion 64, "Monitoring radioactivity releases," of Appendix A, "General position are confined to simple statistical concepts Design Criteria for Nuclear Power Plants," to 10 and prescribe no specific statistical techniques. In fact, the implementation of some specifications by CFR Part 50 requires that nuclear power plant rigorous statistical methods may prove difficult for designs provide means for monitoring the plant en virons for radioactivity that may be released as the some users of the guide. Therefore, good approx result of normal operations, including anticipated imate statistical methods are acceptable.

operational occurrences, and as the result of postulated accidents.

• Lines indicate substantive changes from previous issue.

'ANSI N545-1975, "Performance, Testing, and Procedural Thermoluminescence dosimetry (TLD) is widely Specification for Thermoluminescence Dosimetry (Environmental used to measure levels of X and gamma radiation in Applications)" may be obtained from the American National Standards Institute, 1430 Broadway, New York, New York the environs of NRC-licensed nuclear facilities. This 10018.

guide provides minimum acceptable performance USNRC REGULATORY GUIDES Comments should be sent to the Secretary of the Commission, US. Nuclear Regu latory Commission, Washington, D.C. 20555. Attention: Docketing and Service Regulatory Guides are issued to describe and make available to the public methods Branch.

acceptable to the NRC staff of implementing specific parts of the Commission's regulations, to delineate techniques used by the staff in evaluating specific problems The guides are issued in the following ten broad divisions or postulated accidents, or to provide guidance to applicants. Regulatory Guides 6. Products required. 1. Power Reactors are not substitutes for regulations, and compfiance with them is not 7. Transportation will be accept- 2. Research and Test Reactors Methods and solutions different from those set out in the guides 9. Antitrust Review the issuance or continuance 4. Environmental and Siting able if they provide a basis for the findings requisite to

5. Materials and Plant Protection 10. General of a permit or license by the Commission.

Comments and suggestions for improvements in these guides are encouraged at all Requests for single copies of issued guides (which may be reproduced) or for place times, and guides will be revised, as appropriate, to accommodate comments and ment on an automatic distribution list for single copies of future guides in specific to reflect new information or experience. This guide was revised as a result of divisions should be made in writing to the US. Nuclear Regulatory Commission, Washington, D.C. 20555, Attention Director. Oivision of Document Control substantive comments received from the public and additional staff review,

No specific criteria for good approximation are e. Section 7.2 of ANSI N545-1975 permits the re prescribed. However, the user should judge whether quirements of Section 4 of the standard to be satisfied the sample size is adequately large for the approxima by reference to prior documents. Test results tion and whether the distribution of the measure provided by vendors are examples of such docu ments is sufficiently close to that assumed in the ments. Therefore, when requirements of Section 4 of analysis. Problems relating to underlying distribu the standard can be met by reference to test results tions can be avoided by the use of nonparametric provided by a vendor or other source, additional tests methods. Some of the specifications that are stated in by a licensee are not needed.

terms of standard deviations can be reformulated in nearly equivalent specifications for tolerance limits f. The appendixes to ANSI N545-1975 are not a for which simple nonparametric methods are part of the ANSI standard or of this regulatory guide, available. Such reformulations are also acceptable. which endorses the standard. However, the appen A. Hald2 and W. J. Conover3 are useful reference dixes do provide useful information on the topics sources for parametric and nonparametric methods, covered.

respectively.

C. REGULATORY POSITION

If every TLD is individually calibrated, the popula tion parameters for certain errors can be computed The requirements and recommendations for per directly, and statistical inference is not needed for formance specifications, testing procedures, calibra specifications relating to these errors. tion procedures, field procedures, and reporting procedures that are included in ANSI N545-1975 are generally acceptable to the NRC staff as the basis for Comments received on this guide and subsequent using thermoluminescence dosimetry for the discussions of these comments have indicated a need measurement of X and gamma radiation in the en for the following emphasis on, or clarification of, sec virons of NRC-licensed facilities subject to the fol tions of the guide and ANSI N545-1975 in order to lowing additional provisions and qualifications.

avoid misinterpretations:

1. Section 3, "Performance Specifications," of a. In this guide, the expression environs of NRC ANSI N545-1975 should be supplemented by the fol licensedfacilities includes both the term environment lowing statement: "Subsection 4.2.4 shall apply also as defined in ANSI N545-1975 and the phrase un to the subsections 3.1 and 3.3."

restricted areas as defined in 10 CFR Part 20.

2. Instead of Section 3.1 of ANSI N545-1975, the b. In Section 2, "Definitions," of ANSI N545 following should be used: "The performance of the

1975, the distinction between thermoluminescence TLD system shall be determined under laboratory dosimeter (TLD) and thermoluminescence (TL) conditions and in a known radiation field with an ex phosphor should be noted. As defined in ANSI N545 posure equal to that resulting from an exposure rate

1975, a TLD can, and usually does, contain multiple of 101MR/hr during the field cycle. Ninety-five per TL phosphors or. otherwise provides for multiple cent of the measurements shall fall within 10% of the readings of the exposure. When multiple readings are known exposure."

used for the measurement of the response of a TLD,

that response is an average of the individual readings. 3. Instead of Section 3.3 of ANSI N545-1975, the ANSI N545-1975 refers to these average values rather following should be used: "Ninety-five percent of the than to the individual readings. final values (after all appropriate corrections to the measurements are applied, including those for errors c. Regulatory position 3 of this guide and Section expected under field conditions) shall differ from the

3.3 of ANSI N545-1975 refer to the overall error in correct value by less than 30% of the correct value."

the total field exposure. No method is specified for interpreting field exposures to isolate contributions 4. Instead of Section 4.3.1 of ANSI N545-1975, attributable to a nuclear facility, and no limit is the following should be used: "Uniformity shall be specified on the error associated with estimates of the determined by giving TLDs from the same batch an exposure attributable to the facility. exposure equal to that resulting from an exposure rate of lOtR/hr during the field cycle. The response d. Section 6.3.1 of ANSI N545-1975 specifies field obtained shall have a relative standard deviation exposure at a height of 1 meter above the ground; (coefficient of variation) of less than 7.5%."

however, Section 6.3.3 permits exposure at other heights.

5. Instead of Section 4.3.2 of ANSI N545-1975,

2A. Hald, Statistical Theory with Engineering Applications, John the following should be used: "Reproducibility shall Wiley & Sons, Inc., 1952. be determined by giving one TLD repeated exposures

3W.J. Conover, PracticalNonparametric Statistics, John Wiley & equal to that resulting from an exposure rate of 10

Sons, Inc., 1971. juR/hr during the field cycle. The responses shall have

4.13-2

a relative standard deviation (coefficient of variation) This guide reflects current NRC staff practice.

I

of less than 3.0%." Therefore, except in those cases in which the appli cant or licensee proposes an acceptable alternative method, the staff is using and will continue to use the method described herein in evaluating an applicant's

D. IMPLEMENTATION

or licensee's capability for and performance in com plying with specified portions of the Commission's The purpose of this section is to provide informa regulations until this guide is revised as a result of tion to applicants and licensees regarding the NRC suggestions from the public or additional staff staff's plans for using this regulatory guide. review.

4.13-3

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