Regulatory Guide 8.25
| ML12181A384 | |
| Person / Time | |
|---|---|
| Issue date: | 08/31/1980 |
| From: | NRC/OSD |
| To: | |
| References | |
| Task OH 905-4 RG-8.025 | |
| Download: ML12181A384 (5) | |
U.S. NUCLEAR REGULATORY COMMISSION
9W- August 1980
F REGULATORY GUIDE
,OP OFFICE OF STANDARDS DEVELOPMENT
REGULATORY GUIDE 8.25 (Task OH 905-4)
CALIBRATION AND ERROR LIMITS OF AIR SAMPLING INSTRUMENTS FOR
TOTAL VOLUME OF AIR SAMPLED
A. INTRODUCTION
IV of this manual provide sources of published, recommended, or standard methods; a summary of recommended standard Paragraph (a)(3) of § 20.103, "Exposure of Individuals to methods; and a listing of calibration instruments and their Concentrations of Radioactive Materials in Air in Restricted suppliers.
Areas," of 10 CFR Part 20, "Standards for Protection Against Radiation," requires that licensees use suitable This guide supplements the instructions in this manual measurements of concentrations of radioactive materials in by adding guidance for frequency of calibration, for accept- air for detecting and evaluating airborne radioactivity in able error limits in volume measurement, and for documen- restricted areas. In addition, paragraph (c)(4) of § 20.106, tation.
"Radioactivity in Effluents to Unrestricted Areas," requires that licensees provide information as to the highest concen- tration of each radionuclide in an unrestricted area, a
C. REGULATORY POSITION
procedure that in many cases requires air monitoring beyond the restricted area. This guide identifies methods acceptable to the NRC staff for calibrating air sampling The publication entitled "Air Sampling Instruments for instruments for total volume of air sampled and provides Evaluation of Atmospheric Contaminants," 1 5th Edition, guidance for ensuring that volumes of air sampled are 1978, provides guidance on total air sample volume calibra- known within certain limits. tion methods acceptable to the NRC staff, as supplemented below:
B. DISCUSSION
1. FREQUENCY OF CALIBRATION
In order to accurately assess the air concentration of radioactive materials in a given location, the volume of air A licensee committed to a routine or emergency air sampled as well as the quantity of contaminant in the sampling program should perform an acceptable calibration sample must be determined. Accurate determination of the of all airflow or volume metering devices at least once every volume of air sampled requires standard, reproducible, 6 months, with the exception of permanently installed and frequent calibration of the air metering devices that are effluent monitors.2 Special calibrations should be performed used with air sampling instruments. at any time there is reason to believe that the operating characteristics of a metering device have been changed, by The American Conference of Governmental Industrial repair or alteration, or whenever system performance is Hygienists has published a manual entitled "Air Sampling observed to have changed significantl
y. Routine instrument
1 Instruments for Evaluation of Atmospheric Contaminants," maintenance should be performed as recommended by the
5th Edition, 1978. Part II,Section I, "Calibration of Air manufacturer. Primary or secondary standard instruments Sampling Instruments," of this manual provides instructions used to calibrate air sampling instruments should be inspected for acceptable methods of calibrating air volume and frequently for consistency of performance.
flow rate metering devices. In particular, Tables II, Ill, and
2 See NUREG-0472, "Radiological Effluent Technical Specifica-
1 tions for PWRs," July 1979, and NUREG-0473, "Radiological Copies are available from the American Conference of Govern- Effluent Technical Specifications for BWRs," July 1979, which mental Industrial Hygienists, P.O. Box 1937, Cincinnati, Ohio 45201. specify calibration at least once every 18 months.
USNRC REGULATORY GUIDES Comments should be sent to the Secretary of the Commission, U.S. Nuclear Regulatory Commission Washington, D.C. 20555, Regulatory Guides are issued to describe and make available to the Attention: Docketing and Service Branch.
public methods acceptable to the NRC staff of implementing specific parts of the Commission's regulations, to delineate tech- The guides are issued In the following ten broad divisions:
niques used by the staff In evaluating specific problems or postu- lated accidents or to provide guidance to applicants. Regulatory 1. Power Reactors 6. Products Guides are noi substitutes for regulations, and compliance with 2. Research and Test Reactors 7. Transportation them is not required. Methods and solutions different from those set 3. Fuels and Materials Facilities 8. Occupational Health out in the guides will be acceptable if they provide a basis for the 4. Environmental and Siting. 9. Antitrust and Financial Review findings requisite to the issuance or continuance of a permit or 5. Materials and Plant Protection 10. General license by the Commission.
Copies of issued guides may be purchased at the current Government Comments and suggestions for improvements in these guides are Printing Office price. A subscription service for future guides in spe- encouraged at all times, and guides will be revised, as appropriate, cific divisions is available through the Government Printing Office.
to accommodate comments and to reflect new information or Information on the subscription service and current GPO prices may experience. This guide was revised as a result of substantive com- be obtained by writing the U.S. Nuclear Regulatory Commission, ments received from the public and additional staff review. Washington, D.C. 20555, Attention: Publications Sales Manager.
2. ERROR LIMIT FOR MEASUREMENT OF AIR SAMPLE the determination of total volume, is less than 20 percent.
VOLUME This analysis assumes a linear change in the flow rate across Most methods of calibrating airflow or air volume metering devices require direct comparison to a primary or secondary the sample collector during the sampling period when flow rate meters are used. In turn, this assumption allows simple averaging of the initial and final flow rates for a singleW
a standard instrument to determine a calibration curve or a sample.
correction factor. An example 6.f a primary standard is a spirometer that measures total'air volume directly with high If there are significant differences in pressure and temper- precision by liquid displacement. An example of a secondary ature between the calibration site and the sampling site, standard is a wet-test meter that has been calibrated against appropriate corrections should be made using the ideal gas a primary standard. Primary standards are usually accurate laws as discussed in the previously described manual.
to within 1 percent and secondary standards to within 2 percent. A sample calculation of the most probable value of the cumulative error in total volume measured is as follows- If The significant errors associated with determining the accuracies of the scale reading, the calibration factor, and total air volume sampled are: sample time are +4, 2, and 1 percent, respectively, and there are no other significant sources of error, the cumulative Ec: The error in determining the calibration factor. error would be:
(An acceptable estimate is the percent error associated with 3 the standard instrument used in Ev= [42 +22 + 12]1/2= 4.58%orr,5%
the calibration.)
3. DOCUMENTATION OF CALIBRATION OF AIR
Es: Intrinsic error in reading the meter scale. (An METERING DEVICES
acceptable estimate is the percent equivalent of one-half of the smallest scale division compared to The licensee should maintain records of all routine and the scale reading.) special calibrations of airflow or volume metering devices, including the primary or secondary standard used, method Et: The percent error in measurement of sampling employed, and estimates of accuracy of the calibrated time that should be kept within 1 percent. metering devices. All instruments should be clearly labeled as to the date and results of the most recent calibration and Ev: The most probable value of the cumulative percent should include the appropriate correction factors to be error in the determination of the total air volume used.
sampled.
D. IMPLEMENTATION
E. can be calculated from the following equation pro- vided there are no additional significant sources of errors: The purpose of this section is to provide information to applicants and licensees regarding the NRC staff's plans for Ev [Es2 +Ec +E2]1/2 using this regulatory guide.
Air sampling instruments, including those personal Except in those cases in which an applicant or licensee (lapel) samplers that have flow rate meters, should have proposes an acceptable alternative method for complying flow rate or total volume metering devices calibrated so with § § 20.103 and 20.106 of the Commission's regula- that the most probable value of the cumulative error Ev, in tions, the staff will use the method described herein in the
3 evaluation of ongoing and proposed air monitoring pro- The calibration factor should be based on grams after November 15, 1980.
two kinds of deter- minations. First, correction factors should be determined at several flow rates distributed over the full-scale range. Each flow rate correction factor should be determined while adjusting flow rates If an applicant or licensee wishes to use the method upscale and again while adjusting flow rates downscale, and the two described in this regulatory guide on or before November 15, sets of data should be compared; Second, subsequent calibrations should compare the new correction factors to those determined 1980, the pertinent portions of the application or the during the previous calibration. If observed differences are signif- licensee's performance will be evaluated on the basis of icant compared to the overall volume error limit of 20 percent, an additional error term should be included in the calculation above. this guide.
8.25-2
VALUE/IMPACT STATEMENT
1. PROPOSED ACTION availability of acceptable calibration methods suitable for adoption in their programs.
1.1 Description
1.3.3 Industry Many NRC licensees are required to maintain radiation and contamination survey programs, including air sampling, The value to industry in providing guidance on air to assess concentrations of airborne radionuclides. Regula- volume calibration procedures consists of the probable tory concentration values are specified in Appendix B to improvement in worker protection from more accurate
10 CFR Part 20. The proposed action is to provide guidance assessment of airborne radioactive material hazards. The for improving air sampling procedures in the form of impacts include equipment and manpower costs that do not acceptable methods of calibrating air sampling instruments appear to be excessive in view of the proposed acceptable for determining total volume of air sampled, frequency of methods and frequency of calibration requirements. The calibration, and documentation procedures. Measurement staff estimates the initial cost of an acceptable calibration
.of the total volume is required in the calculation of the system to be less than $300 and approximate man-power concentration. requirements to be 1 to 2 man-hours per year per instrument.
1.2 Need for Proposed Action 1.3.4 Workers In order to accurately characterize the air quality of a For the workers, the values of improved air monitoring working environment, the volume of air sampled as well as include more accurate assessments of the quality of the the quantity of contaminant must be determined. Accurate working environment and a probable reduction in internal assessment of the quantity of air sampled requires frequent radiation exposure. Recent staff discussion with union calibration of air metering devices by standard, reproducible representatives indicates that there is an increasing concern methods. To assess internal exposure resulting from airborne about exposure to airborne radioactive material on the part radioactive material and to evaluate working conditions, of workers in the industry. Continued NRC efforts to acceptable standard calibration and measurement methods increase our understanding of this aspect of radiation must be developed. The Office of Nuclear Materials Safety hazard and to improve monitoring and control of airborne and Safeguards requested the Office of Standards Develop- radioactivity is essential.
ment to accelerate the schedule for issuing guidance to NRC licensees on acceptable methods for total volume 1.3.5 Public calibration and measurement.
Environmental monitoring to assess the release of
1.3 Value/Impact of Proposed Action radioactive materials in the vicinity of NRC-licensed facil- ities includes air sampling. Calibration procedures for
1.3.1 NRC Operations low-flow-rate, continuous air sampling instruments will be included. The public will benefit from increased reliability Acceptable methods for calibrating air sampling instru- of environmental measurements.
ments provide additional criteria for inspection and enforce- ment of NRC radiation protection regulations. Increased 1.4 Decision accuracy in assessing airborne radioactive material concen- trations would provide a more reliable data base for develop- The NRC should develop and provide guidance on ing additional regulatory action to control and reduce acceptable total air volume calibration methods for those internal radiation exposure. Impacts of the development of types of radiological air sampling instruments used by guidance as described include task completion manpower licensees.
cost, estimated to be 0.3 man-year, and printing costs of approximately $300.
2. TECHNICAL APPROACH
1.3.2 Other Government Agencies The action proposed here is to provide guidance on Coordination with several governmental agencies (e.g., acceptable methods of calibrating airflow and air volume NBS, OSHA, EPA) has been necessary to ensure consistency metering devices on radiological air samplers. Survey in cases where respective regulatory and monitoring func- programs and, where appropriate, air monitoring programs tions interface. Agreement States whose licensing regulations are required of many NRC licensees. It is our intent that include air sampling requirements may benefit by the acceptable methods of air volume calibration be a required
8.25-3
component of licensee monitoring procedures. There are no regulatory guide could reference existing and acceptable technical alternatives- to providing this guidance. standard calibration methods or adequately describe calibra- tion procedures acceptable to the NRC staf
f. The staff does
3. PROCEDURAL APPROACH not consider that revision of any existing regulatory guides could provide the objectives proposed here.
3.1 Procedural Alternatives
3.3 Decision on Procedural Approach The proposed action, to publish guidance on calibration procedures for radiological air sampling instruments, could The staff concludes that a regulatory guide adopting be accomplished by several methods: publishing an NRC acceptable methods for total air volume calibration for regulation requiring that specific calibration procedures be radiological air sampling instruments should be published.
used by all licensees; preparing or revising a regulatory guide (based on the existing paragraph 20.201(b) of 10 CFR 4. STATUTORY CONSIDERATIONS
Part 20) that would provide an acceptable method for calibration; developing an ANSI standard on calibration 4.1 NRC Regulatory Authority procedures that could be endorsed by a new regulatory guide; or publishing a NUREG report or a branch position Paragraph 20.201 (b) of 10 CFR Part 20 establishes a legal paper. requirement that each licensee make or cause to be made such surveys as may be necessary for him to comply with the
3.2 Value/Impact of Procedural Alternatives regulations. The NRC is thus authorized to provide criteria for acceptable survey methodology, including calibration of An NRCregulation establishes general legal requirements, instrumentation.
is more costly and time consuming to prepare, and is not an appropriate vehicle for the specific and narrow objective pro- 4.2 Need for NEPA Statement posed here. One advantage is that a regulation legally requires compliance. In general, this approach is not considered cost The action proposed here is not considered to constitute effective in view of the objective of the proposed action. a major addition or change and would entail no effect on the environment. The staff does not believe that an environ- ANSI standards are generally intended as technical mental impact statement is necessary.
treatments of broad areas of concern to industr
y. An ANSI
standard concerning all aspects of an acceptable monitoring 5. RELATIONSHIP TO OTHER EXISTING OR PROPOSED
program would be appropriate but beyond the narrower REGULATIONS OR POLICIES
objective proposed here. Developing an ANSI standard and an endorsing regulatory guide might require several years Several regulatory guides concerning health physics and would be costly. This approach is not considered cost surveys at various types of NRC-licensed facilities such as effective in view of the proposed objective. Regulatory Guide 8.21, "Health Physics Surveys for Bypro- duct Material at NRC-Licensed Processing and Manufactur- A NUREG report would be an appropriate vehicle for ing Plants," are in preparation. These guides would appro- reporting on technical studies of various methods of calibrat- priately reference the guide proposed here. In addition, ing air samplers. Regulatory guidance, however, is not guides such as Regulatory Guide 1.70, "Standard Format established through publication of a NUREG report. and Content of Safety Analysis Reports for Nuclear Power Since this proposal includes establishing an acceptable Plants," will include a commitment to acceptable air method for compliance with required surveying programs, a sampler calibration procedures. When next revised, these NUREG report is not considered suitable. guides should include cross-references to this guide as an acceptable element of a licensee's monitoring program.
Branch position statements are intended as interim measures to be used when an immediate response is required. The proposed guide is consistent with Regulatory They are usually superseded when a more permanent mode Guide 8.8, "Information Relevant to Ensuring That Occupa- of guidance is developed. tional Exposures at Nuclear Power Stations Will Be As Low As Is Reasonably Achievable." When next revised, Regula- A regulatory guide can be prepared at reasonable cost tory Guide 8.8 should include a cross-reference to this guide.
within a reasonable time period. A regulatory guide can establish acceptable criteria for compliance with a regulatory 6. SUMMARY AND CONCLUSIONS
requirement and, if incorporation into a license is requested, is subject to inspection and enforcement. In summary, it is proposed that a regulatory guide be published for the purpose of providing guidance on accept- Development of a regulatory guide allows extensive input able methods of calibrating radiological air sampling instru- from all segments of the nuclear industry and the public. A ments for total volume of air sampled.
8.25-4
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