Regulatory Guide 8.32

(Task OP 713-4), Criteria for Establishing a Tritium Bioassay Program

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July 1988 V0, p~k REG4[,4 9, U.S. NUCLEAR REGULATORY COMMISSION

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REGULATORY GUIDE

OFFICE OF NUCLEAR REGULATORY RESEARCH

REGULATORY GUIDE 8.32 (Task OP 713-4)

CRITERIA FOR ESTABLISHING A TRITIUM BIOASSAY PROGRAM

A. INTRODUCTION

Any information collection activities mentioned in this regulatory guide are contained as requirements in 10 CFR Part 20, which pro Section 20.108, "Orders Requiring Furnishing of Bioassay Serv vides the regulatory basis for this guide. The information collec ices," of 10 CFR Part 20, "Standards for Protection Against Radia tion requirements in 10 CFR Part 20 have been cleared under OMB

tion," states that the Nuclear Regulatory Commission (NRC) may Clearance No. 3150-0014.

incorporate into a license provisions requiring a specific program of bioassay measurements as necessary or desirable to aid in deter

B. DISCUSSION

mining the extent of an individual's exposure to concentrations of radioactive material. The topics treated in this guide include determinations of (1)

whether bioassay should be performed, (2) frequencies of bioassay, This guide provides NRC staff guidance on: (3) who should participate, (4) the actions to take based on bioassay results, and (5) the activity levels that should initiate such actions.

1. The conditions under which the NRC staff will consider the need for license conditions related to tritium bioassays under The information and references that were used in developing this

§ 20.108 of 10 CFR Part 20. guidance are summarized in NUREG-0938, "Information for Establishing Bioassay Measurements and Evaluations of Tritium

2. The scope, types, and frequency of tritium bioassay programs Exposure." 3 NUREG-0938 also contains information that may be conducted by licensees for the purpose of demonstrating compliance useful to applicants and licensees in planning and conducting with applicable provisions of 10 CFR Part 20 or for satisfying license bioassay programs for tritium.

conditions imposed under § 20.108. However, if this guide differs from the requirements of any existing license condition, the licensee The triggering concentrations given in Table 1 of this guide not should conform to such requirements until the license is amended withstanding, licensees are not exempt from the air sampling and in accordance with the Commission's regulations. bioassay requirements of 10 CFR Part 20; particular attention should be given to paragraphs 20.103(a)(3) and 20.103(c)(2). Paragraph This guide provides criteria acceptable to the NRC staff for 20.103(a)(3) requires licensees to measure radioactivity concentra developing and implementing a bioassay program for any licensee tions in the air and, as appropriate, to use bioassay measurements handling or processing tritium' either as pure gas or in various for the timely detection and assessment of individual intakes of chemical compounds. It further provides guidance to such licensees radioactivity. Paragraph 20.103(c)(2) requires licensees to provide on selecting workers who should participate in a program to detect bioassays as appropriate to evaluate actual exposures when the and measure possible internal radiation exposure. This guide is pro licensee wishes to make allowance for the use of respiratory pro grammatic in nature and does not deal with measurement techniques tection equipment in estimating exposures of individuals to airborne

2 and procedures. radioactive material. The "appropriateness" of conducting bioassays

'Tritium, an isotope of hydrogen, has a mass number of 3 (2 neutrons, 1 to comply with paragraphs 20.103(a)(3) and (c)(2) must be judged proton). Tritium may be symbolized or represented in the literature by the on a case-by-case basis. For example, if the Table 1 concentration standard scientific symbol 3H or by other symbols adopted for convenience criteria are routinely met, but there are unexpectedly high air sam in publication such as hydrogen-3, H-3, or T. pling results, bioassays may be "appropriate" in order to verify

2 Sections 8 through 11 of ANSI N13.14-1983, "American National Stand and assure that regulatory intake limits have not been exceeded.

ard for Dosimetry -Internal Dosimetry Programs for Tritium Exposure 3 Minimum Requirements," contain some useful information on procedural NUREG-0938 is available from The Superintendent of Documents, U.S.

aspects of bioassay programs. ANSI N13.14-1983 is available from the Government Printing Office, P.O. Box 37082, Washington, DC 20013-7082;

American National Standards Institute, Inc., 1430 Broadway, New York, or from the National Technical Information Service, 5285 Port Royal Road, NY 10018. Springfield, VA 22161.

USNRC REGULATORY GUIDES The guides are issued in the following ten broad divisions:

Regulatory Guides are issued to describe and make available to the public methods acceptable to the NRC staff of implementing 1. Power Reactors 6. Products specific parts of the Commission's regulations, to delineate tech- 2. Research and Test Reactors 7. Transportation niques used by the staff in evaluating specific problems or postu- 3. Fuels and Materials Facilities 8. Occupational Health lated accidents, or to provide guidance to applicants. Regulatory 4. Environmental and Siting 9. Antitrust and Financial Review Guides are not substitutes for regulations, and compliance with 5. Materials and Plant Protection 10. General them is not required. Methods and solutions different from those set out in the guides will be acceptable if they provide a basis for the findings requisite to the issuance or continuance of a permit or Copies of issued guides may be purchased from the Government license by the Commission. Printing Office at the current GPO price. Information on current GPO prices may be obtained by contacting the Superintendent of This guide was issued after consideration of comments received from Documents, U.S. Government Printing Office, Post Office Box the public. Comments and suggestions for improvements in these 37082, Washington, DC 20013-7082, telephone (202)275-2060 or guides are encouraged at all times, and guides will be revised, as (202)275-2171.

appropriate, to accommodate comments and to reflect new informa tion or experience. Issued guides may also be purchased from the National Technical Written comments may be submitted to the Rules and Procedures Information Service on a standing order basis. Details on this Branch, DRR, ADM, U.S. Nuclear Regulatory Commission, service may be obtained by writing NTIS, 5285 Port Royal Road, Washington, DC 20555. Springfield, VA 22161.

Table 1 ACTIVITY LEVELS OR CONCENTRATIONS ABOVE WHICH

TRITIUM BIOASSAY PROGRAMS SHOULD BE PROVIDED

HTO Mixed with More HTOb and Other Tritiated Tritium (HT or T 2)c Than 10 kg of Inert Compounds (Including Gas in Sealed H 20 (e.g., in Reactor Types of Operationa Nucleotide Precursors) Process Vesselsd Coolant)e Processes in open room or bench with possible escape of 0.1 Ci 100 Ci 0.01 Ci/kg tritium from process vessels Processes with possible escape of tritium carried out within 1 Ci 1,000 Ci 0.1 Ci/kg a fume hood of adequate design, face velocity, and performance reliability Processes carried out within gloveboxes that are ordinarily 10 Ci 10,000 Ci I Ci/kg closed but with possible release of tritium from process vessels and occasional exposure to contaminated box and leakage aQuantities (< 10 kg) of substances containing tritium that are present during operations may be considered to be either the amount processed by an individual at any one time (when accidental intake is more likely) or the amount of activity that entered into the process (throughput) during any one month (when routine handling of repeated batches is the more likely source of exposure).

bHTO is a symbol for a water molecule in which a tritium atom (T) is present in place of a normal hydrogen atom (H).

CA molecule of hydrogen gas contains two hydrogen atoms. Either one of these atoms may be replaced with T to form HT, or two T atoms may combine to form T2 gas.

dThis assumes that adequate air monitoring has established that there is no tritium leakage or that no significant amount of tritium gas can be converted to HTO before intake.

eThis column is applicable in place of the previous two columns in cases where tritium can be identified at measurable concentrations in large amounts of water or other substances, such as at nuclear power plants.

For the user's convenience, the following terms are presented processed per month exceed those shown in Table 1 for each form with their definitions as used in this guide: of tritium.

1.2. For workers in nuclear reactor facilities, urine bioassay Bioassay-The determination of the kind, quantity or concen should be performed when the concentrations of tritium in the tration, and location of radioactive material in the human body by reactor coolant water exceed those shown in the right-hand column direct (in vivo) measurement or by analysis (in vitro) of materials of Table 1. The lowest value in Table 1, 0.01 Ci/kg of coolant, excreted or removed from the body. Only in vitro analysis of urine should be used to initiate a bioassay program whenever employees (or, if more convenient, another representative body fluid) is are exposed to the air in a room or area where more than 10 kg applicable to tritium or its compounds. of water containing this or greater concentration or a total of more than 0.1 Ci of tritium is in contact with the air (such as a storage Intake-The total quantity of radioactive material entering the pool). If exposure to water containing a concentration of tritium body. greater than or equal to 1 Ci/kg is expected, such as when leakages occur, a bioassay program should be initiated because significant Uptake-The total quantity of radioactive material retained in intakes, both by inhalation and by absorption of water vapor through the body (i.e., not immediately exhaled) after an intake. the skin, can occur when individuals are exposed to tritium at these concentrations.

C. REGULATORY POSITION

1.3. Bioassays should also be performed when an employee can

1. CONDITIONS UNDER WHICH BIOASSAY come into skin contact with, ingest, or absorb into the body through IS NECESSARY cuts, abrasions, or accidental (hypodermic) injection, water or any other substance with concentrations of tritium greater than or equal

1.1. Routine bioassay is necessary when quantities of tritium to 0.01 mCi/kg (0.01 1iCi/cc) such as may be common in laboratory processed by an individual at any one time or the total amounts applications.

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2. PARTICIPATION 4.2.1 The average urinary tritium concentration in specimens obtained from the worker during the three-month period does not All workers involved in the processing of tritium under condi exceed 3 p.Ci/L,

tions specified in Regulatory Position 1 or in the environs of the process should participate in the bioassay program. 4.2.2. If measurements of the concentration of tritium in air are required as a condition of the license, the quarterly average con

3. TYPES OF BIOASSAY THAT SHOULD BE centration (pCi/mL) to which workers are exposed multiplied by PERFORMED the factor 6.3 X 108 mL does not exceed 0.8 mCi, and

3.1 Baseline (Preemployment or Preoperational) 4.2.3. The working conditions during the three-month period, with respect to the potential for tritium exposure, are representative A baseline bioassay of each worker should be conducted before of working conditions during the period in which a quarterly that worker begins working with tritium in amounts that would urinalysis frequency is employed, and there is no reasonable require initiation of a bioassay program as specified in Regulatory expectation that the criteria given in items 4.2.1 and 4.2.2 above Position 1. will be exceeded.

3.2 Routine 5. ACTION POINTS AND CORRESPONDING ACTIONS

Regular bioassays should be conducted to monitor routine opera 5.1 Biweekly or More Frequent Sampling tions at frequencies specified in Regulatory Position 4.

5.1.1. Whenever the intake of tritium within any 40-hour work

3.3 Postoperational and with Termination Physical period exceeds the amount that would be taken into the body from Examination uniform exposure for 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> at the air concentration (5 X 10-6 fiCi/mL) specified in Table 1, Column 1, of Appendix B to 10 CFR

A bioassay should be performed within one month after the last Part 20,4 the licensee is required to make evaluations, take necessary possible exposure to tritium, when operations are being discon corrective actions, and maintain records as specified in paragraph tinued, or when the worker is terminating activities with potential 20.103(b)(2) of 10 CFR Part 20.

exposure as indicated by the criteria in Table 1.

5.1.2. If urinary excretion concentrations exceed 5 fACi/L but

3.4 Diagnostic are less than 50 fCi/L, the following course of action should be taken:

A followup bioassay should be performed as soon as possible but not later than one week after any sample exceeding levels given 1. An investigation of the operations involved, including as action points in Regulatory Position 5 in order to confirm the surveys and monitoring of air and surface contamination, initial results and, in the case of a single intake, to allow an estimate should be carried out to determine the causes of the intake, of the effective half-life of the tritium in the body. If the initial sam and an evaluation of the potential for further larger in ple or other data indicates a possible exposure high enough to war takes or of the possible involvement of other employees rant immediate medical attention, complete and immediate followup should be performed.

should be conducted as described in Regulatory Position 5.1.3.

2. Any reasonable corrective actions that the investigation

4. FREQUENCY OF SAMPLING indicates may lower the potential for further exposures should be implemented.

4.1 Initial Routine

3. A repeat urine sample should be taken within one week A bioassay sample should be taken within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, if possible, of the previous sample and should be evaluated within a but not later than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following entry of an individual into 4 Multiplying the concentration given in Appendix B, 5 x 10-6 pCi/mL, by an area where operations require bioassay according to Regulatory 6.3 X108 mL gives the corresponding quarterly intake limit of tritium by Position 1. Sam1 tes should then be taken every two weeks or more inhalation. In the case of inhaled HTO, which mixes instantly with other frequently as long 2s the individual is working with tritium. When water molecules after entering body fluids, the intake may be assumed equal work with tritium is on an infrequent basis (less frequently than to uptake. The uptake of tritium (as HTO) by absorption through the skin every two weeks), bioassay should be performed within ten days is assumed equal to the uptake by inhalation unless the form of tritium in of the end of the work period during which tritium was handled. the air can be demonstrated to have lower uptakes. The total uptake, including Samples should not be collected until two hours after termination skin absorption, would be assumed to be about 6.3 mCi, which delivers of the potential exposure in order that bladder contents will have a dose commitment of about 1.25 rems to standard man (using the quality had time to equilibrate with other body water. factor Q= 1.7). A 40-hour occupational exposure at a concentration of

5 X 10-6 yCi/mL would thus result in an intake of 6.3/13 =0.48 mCi and a dose commitment of about 0.1 rem. An acute intake (inless than one day)

4.2 After Three Months of 0.48 mCi would result in an initial body water concentration of about

11 piCi/L. (The use of Q = 1.7 in this example follows the practice used A sampling frequency selected in accordance with Regulatory in developing concentration limits for the current 10 CFR Part 20. Changes Position 4.1 may be changed to quarterly it, after three months, in recommendations of various committees and a review of quality factor the following three conditions are met: determinations reported in the literature are presented in NUREG-0938.)

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week after collection. Internal dose commitments should less than 5 pCiIL. If there is a possibility of long-term be estimated using at least these two urine sample evalua organic compartments of tritium that require evaluation tions and other survey data, including the probable times (see NUREG-0938), continue sampling as long as of the intake of tritium. necessary to ensure that appreciable exposures to these other compartments do not go undetected and to provide

4. Any evidence indicating that further work in the area might estimates of total dose commitments.

result in an employee receiving a dose commitment in excess of the limits established in § 20.101 should serve 5.2 Quarterly Sampling as cause to remove the employee from work in this opera tion until the source of exposure is discovered and Carry out the actions called for when any of the action levels corrected. indicated in Regulatory Position 5.1 are exceeded. In addition, institute biweekly (or more frequent) sampling for at least the next

5. Reports or notifications must be provided as required by six-month period, even when urinary concentrations fall below 5

§§ 20.405, 20.408, and 20.409 of 10 CFR Part 20 or as jACiIL.

required by conditions of the license pursuant to § 20.108 of 10 CFR Part 20.

D. IMPLEMENTATION

5.1.3. If urinary excretion concentrations exceed 50 pCiIL, the following course of action should be taken: The purpose of this section is to provide information to applicants and licensees regarding the NRC staff s plans for using this

1. Carry out all steps in Regulatory Position 5.1.2. regulatory guide.

2. If the projected dose commitment exceeds levels for the Except in those cases in which an applicant or licensee proposes whole body as provided in § 20.403 of 10 CFR Part 20, an acceptable alternative method for complying with specified notify the NRC as appropriate. portions of the Commission's regulations, or cases in which dif ferent requirements are imposed by any existing license condition,

3. Refer the case to appropriate medical and health physics the methods described in this guide will be used in evaluating the consultants for recommendations regarding the need for need for license conditions related to tritium bioassay programs and immediate therapeutic procedures that may be carried out in evaluating the radiation protection programs of licensees that have to accelerate removal of tritium from the body. bioassay requirements incorporated in their licenses in accordance with § 20.108 of 10 CFR Part 20. This guide will also be used in

4. Carry out repeated sampling at approximately one-week evaluating changes to existing bioassay programs that may be re intervals at least until urine samples show concentrations quested by licensees.

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BIBLIOGRAPHY

American National Standards Institute, "American National Johnson, J. R., "Frequency of Bioassay Monitoring for Internal Standard for Dosimetry--Internal Dosimetry Programs Contamination and Its Relationship to Sensitivity and Accuracy for Tritium Exposure-Minimum Requirements," ANSI Requirements," Health Physics, Vol. 46, p. 715, 1984.

N13.14-1983,1 1983.

Kinslow, R., J. J. Moschella, and C. N. Cawley, "A Model of Brodsky, A., "Information for Establishing Bioassay Measure Urinary Tritium Following Multiple Contaminations," Health ments and Evaluations of Tritium Exposure," NUREG-0938,2 Physics, Vol. 46, pp. 1154-1155, 1984.

U.S. Nuclear Regulatory Commission, Washington, DC,

1983. Minister of National Health and Welfare of Canada, "General Guidelines for Bioassay Programs," Bioassay Guideline 1, Report Duijsings, J. H., et al., "Internal Contamination of Radio 80-EHD-56, 4 1980.

logical Workers by Tritium Compounds at Two Universities in the Netherlands," Health Physics, Vol. 46, pp. 665-669, Minister of National Health and Welfare of Canada, "Bioassay Guide

1984. line 2, Guidelines for Tritium Bioassay," Report 83-EHD-87, 4 1987.

International Commission on Radiological Protection, "Limits for Myers, D. K., and J. R. Johnson, "Estimating the Biological Intakes of Radionuclides by Workers," ICRP-30,' Part 1, 1979. Hazards of Tritium," Health Physics, Vol. 46, p. 715, 1984.

'Copies of ANSI standards may be purchased from The American Smith, L. R., et al., "Human Execretion Patterns Following National Standards Institute, 1430 Broadway, New York, NY Occupational Uptake of 3H, 14C, and 35S-Labelled Compounds,"

10018.

2 Health Physics, Vol. 44, pp. 221-234, 1983.

Copies may be purchased from the U.S. Government Printing Office,

4 Post Office Box 37082, Washington, DC 20013-7082. Copies may be obtained from the Minister of National Health and Welfare

3 Copies may be purchased from Pergamon Press, Inc., Maxwell House, of Canada, Radiation Protection Bureau, Brookfield Road, Ottawa, Ontario Elmsford, NY 10523. KlA IC1, Canada.

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VALUE/IMPACT STATEMENT

A draft value/impact statement was published with Draft prepared. A copy of the draft value/impact statement is available Regulatory Guide OP 713-4 when the draft guide was published for inspection and copying for a fee at the Commission's Public for public comment in June 1983. No changes were necessary, so Document Room at 1717 H Street NW., Washington, DC, under a separate value/impact statement for the final guide has not been Task OP 713-4.

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