ML003739609

Regulatory Guide 8.24, Revision 1, Health Physics Surveys During Enriched Uranium-235 Processing and Fuel Fabrication

ML003739609
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Issue date:	10/31/1979
From:	Office of Nuclear Regulatory Research
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RG-8.24
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Revision 1 U.S. NUCLEAR REGULATORY COMMISSION October 1979 REGULATORY GUIDE OFFICE OF STANDARDS DEVELOPMENT REGULATORY GUIDE 8.24 HEALTH PHYSICS SURVEYS DURING ENRICHED URANIUM-235 PROCESSING AND FUEL FABRICATION A. INTRODUCTION (Ref. 8). More recent reports (Refs. 9-10) contain addi-tional information for use in establishing radiation survey Paragraph 20.201(b) of 10 CFR Part 20, "Standards for programs and selecting methods and equipment for their Protection Against Radiation," requires that each licensee implementation. Surveys are necessary supplements to make or cause to be made such surveys as may be necessary personnel monitoring, in which devices worn by the workers for him to comply with the regulations in that part. As used measure individual external radiation exposures, and to in Part 20, the term "survey" is defined as an evaluation of various forms of bioassay to determine intake of radioactive the radiation hazards incident to the production, use, release, material by the workers.

disposal, or presence of radioactive materials or other sources of radiation under a specific set of conditions. This Some enriched uranium processing and fuel fabrication guide specifies the types and frequencies of surveys that are plants conduct operations with Class D (transportable, with acceptable to the NRC staff for the protection of workers rapid clearance from the lung) uranium compounds for in plants licensed by the NRC for processing enriched which considerations of chemical toxicity to the kidney are uranium and for the fabrication of uranium fuel. limiting. (There are other chemical hazards such as HF that are not addressed in this guide.) Other plants conduct opera-This guide does not relate to the processing of ura- tions with Class W or Y (nontransportable, with 50- or 500-nium-233. Further, this guide does not specifically deal day biological half-life in the lung) compounds only. In the with a number of aspects of an acceptable occupational latter case, considerations of dose equivalent to the lung are health physics program that are closely related to surveys: limiting. Such differences in plant operation were considered (I) the number and qualification of the health physics staff; in the development of this guide.

(2) instrumentation, including types, numbers of instru-ments, limitations of use, accuracy, and calibration; (3) C. REGULATORY POSITION personnel dosimetry; and (4) bioassay. Guidance on bio-assay for uranium appears in Regulatory Guide 8.11, Methods, procedures, and criteria in this guide are accept-

"Applications of Bioassay for Uranium." able to the NRC staff and may be incorporated into appro-priate sections of a license application. This guide is intended B. DISCUSSION to assist applicants in preparing license applications and to assist licensees in establishing acceptable survey programs in Surveys are considered to be part of a comprehensive accordance with the "as low as is reasonably achievable" protection program established by the licensee according (ALARA) philosophy.

to the philosophy and principles of Regulatory Guide 8.10, "Operating Philosophy for Maintaining Occupational Radia- 1. TYPES OF SURVEYS tion Exposures As Low As Is Reasonably Achievable."

Principles, methods, and instrumentation for carrying out 1.1 General Description radiation and contamination surveys were developed early in the atomic energy program and have been discussed in Section 20.201 of 10 CFR Part 20 specifies that surveys reports of the National Council on Radiation Protection be performed to'demonstrate compliance with the other ra-and Measurements (NCRP) (Refs. 1-3), the International diation safety requirements of that part. Certain of these Atomic Energy Agency (IAEA) (Refs. 4-7), and the Inter- surveys are necessary to evaluate external exposure to person-national Commission on Radiological Protection (ICRP) nel and concentrations of airborne uranium in the facility 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.

pubic 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.

and in effluents from the facility. Monitoring of effluents is staff as described in Regulatory Position C.2. Results of beyond the scope of this guide. 1 Applicable guides of Divi-these surveys should be recorded as described in Regulatory sions 4 and 10 should be consulted for such guidance. Position C.3.

Occupational radiation protection programs at enriched Where operating personnel are subject to receiving more uranium processing and fuel fabrication plants should include than 25% of the dose limits, surveys are not normally accept-the types of surveys discussed below, Acceptable survey able for compliance with the personnel monitoring require-frequencies are discursed in Regulatory Position C.2.

ments of § 20.202 of 10 CFR Part 20. However, in the absence of personnel dosimetry data, due, for example, to 1.2 Surveys of External Radiation Dose Rates loss of chemical or physical damage to the dosimeter, an alternative means of estimating the exposure is to use survey NRC licensees are required by § 20.202 of 10CFR Part 20 data in conjunction with appropriate occupancy factors.

to supply appropriate personnel monitoring equipment to In such a case, the estimate, including the survey data used, each individual who enters a restricted area under such cir-must be documented and retained indefinitely along with cumstances that he is likely to receive a dose in any calendar personnel monitoring records pursuant to paragraph 20.401 quarter in excess of 25% of values specified in paragraph 2 (c)(2)(ii). Survey results should be reviewed promptly by 0.101(a) and to require the individual to use the equipment.

the health physics staff in conjunction with personnel Health physics personnel should conduct initial surveys to monitoring records (1) to identify potentially hazardous identify all areas and operations where personnel monitor-situations and unfavorable trends and (2) to ensure that ing may be required and periodic surveys to detect any all personnel are adequately monitored and that exposures changes. The survey instruments used should be operable are maintained as low as is reasonably achievable. Surveys and capable of measuring, at or below the required level, for alpha radiation in enriched uranium processing and fuel the types of radiation that will be encountered. Note that fabrication areas are conducted primarily to assess the if workers will occupy the area essentially full time (520 extent of contamination of personnel, equipment, and hours per quarter), periodic surveys should be made for premises and to detect the loss of confinement. Such beta-gamma radiation at levels as low as 0.24 mrem/hr.

surveys are discussed in more detail in following sections.

Such levels may exist in a large fraction of the area of an enriched uranium processing or fuel fabrication plant unless 1.3 Measurements of Uranium Concentrations in Air considerable care is taken to minimize exposures. Beta-gamma radiation levels of I to 2 mrem/hr usually exist It is essential to establish a comprehensive program for at a distance of one foot or more from the surfaces of UO assessing concentrations of uranium in air, at frequencies pellet trays or boats and fuel rods or bundles and in areas2 specified in Regulatory Position C.2 below, for each area where fuel bundles are stored. Radiation levels of 5 to 10 where operations could expose workers to the intake of mrem/hr may be found at the surfaces of fuel rods and quantities of uranium exceeding those specified in § 20.103.

bundles, and levels of 50 to 100 mrem/hr may be found near Special requirements for such assessments may also be made the surface of pellet trays and boats. Care should be taken a condition of the NRC license. Air samples should be to survey and assess doses to hands and lenses of eyes collected in such a way that the concentrations of uranium received by workers handling process materials (with gloves are representative of the air in which workers are exposed.

or short tools). Much higher levels of gamma radiation may exist at such points as multiply used UF cylinders or where 6 Air sampling may be accomplished using fixed-location operations involving melting or reduction to uranium metal samplers for basic evaluation of the exposure of workers, are conducted and the thorium and protactinium daughters personal (lapel) samplers for supportive measurements and of uranium become separated as "bottoms," scale, or residue.

special studies, and air monitors for early warning of The radiation levels near such sources should be surveyed.

unexpected releases.

Although most of the radiation levels in operating areas are low, a reasonable effort should be made to minimize indi-When radiometric measurements of the quantity of ura-vidual and collective (man-rem) doses.

nium deposited on or in an air sample filter are being performed, appropriate corrections should be included for Preoperational, routine, and special radiation surveys of geometry and alpha (or beta) absorption by the filter media the plant areas should be performed by the health physics and by material collected on the filter. Filter media used should retain collected material on the filter surface, and correction should be made for filter efficiency considering IHowever, the radiation safety program should include surveys the particle sizes and flow rates involved. Overestimates of or records that indicate control of the quantities of radioactive mate-rial released in air and water to unrestricted areas as required by the volume of air that has passed through the filter should 10 CFR Part 20.

be avoided by accurate calibration of the flow rate and by 8.24-2

prevention of or correction for loss of flow rate due to the conditions make it likely that an intake of uranium exceed-accumulation of material on the filter. A means for measur- ing the limits in § 20.103 may occur.

ing flow rate at air sampling heads should be available.

The principal function of the air monitor is to alert Any air samples that are suspected of reflecting releases personnel to take immediate action to protect themselves and high concentrations, such as samples taken during glove- from unexpected airborne uranium. Inhalation exposures box glove changes, should be counted at once to identify are in progress during the time between the release of the any samples with quantities of uranium greater than expected uranium and the sounding of the alarm. Thus every reason-for the sampling location and volume. Procedures used able effort should be taken to reduce this time period. In should ensure prompt correction of the faulty control or particular, the air inlet of the monitor should be located operation that led to the release and high sample. Air near the potential source of airborne uranium, preferably samples should be counted again for record purposes after between the source and the workers. The use of excessively a routine period of time (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is frequently used) for long tubing or piping leading to the inlet should be avoided decay of the "background" radon and thoron. The samples because of the high probability ?if alarm delay due to ura-should be counted for a sufficiently long period of time or nium deposition on the interior walls of the tube or pipe.

until a sufficiently large number of counts has been observed The intake by personnel should be reduced by the choice to establish the sample counting rate error within + 30%. of setpoint. However, the setpoint should not cause false alarms that weaken the workers' confidence in the air Filters from personal (lapel) samplers should be counted monitor. The intake by personnel may also be reduced by and the data related to the uranium intake of the wearer by providing a high flow rate of air through the filter. It is application of factors for sampling time, breathing rate, important to maximize this flow rate, thus reducing the wearing time, and total working time. Filters from general time of exposure before the alarm.

air samplers should be changed each working shift or more often in the event of rapid buildup of material on the filter 1.4 Surface Contamination Surveys media, which reduces the air flow. Consideration may be given to running samplers over weekends when no work is For contamination control inside the restricted area of a in progress or to changing part of the samplers each day of plant, there are controlled areas where uncontained uranium a weekend. is handled and uncontrolled areas where uranium is in the form of sealed sources or is not handled at all. Routine Paragraph 20.203(d) of 10 CFR Part 20 defines "airborne monitoring for uranium contamination that could be present radioactivity area" and prescribes posting requirements. In on surfaces of floors, walls, plant equipment, or furniture in setting forth the standards for limiting intake of uranium, controlled areas is a necessary part of the survey program.

Section 20.103 requires licensees to use process and other The failure to control surface contamination may result in engineering controls to the extent practicable to limit con- unnecessary external or internal exposure of personnel to centrations of radioactive material in air to levels below radiation. Although surface contamination contributes to those which delimit an airborne radioactivity area. That sec- the external radiation dose of workers, the primary concern tion also provides for the use of other precautionary proce- is to avoid internal deposition resulting from the intake of dures such as increased surveillance, limitation of working loose uranium by inhalation, ingestion, or penetration of times, or provision of respiratory protective equipment to the skin.

maintain intake of radioactive material as low as is reason-ably achievable. Health physics surveys of air concentra- For the purposes of this guide, removable contamination tion are essential in evaluating the changes obtained under is that uranium contamination present on a surface that can process and engineering controls, in conducting increased be transferred to a dry smear test paper by rubbing with surveillance and limiting working times, and in support of a moderate pressure. Methods and instruments used in sur-program for the use of respiratory protective equipment. An veys of removable surface contamination should be capable air monitor2 may be used to provide a warning signal of detecting the alpha radiations from uranium at and below that the concentration of airborne uranium has become the levels specified in Table 2. For example, smear counting unexpectedly high. An air monitor should be considered if may be performed with proportional counters, alpha scintilla-tion counters, or thin-window Geiger-Mueller (GM) tubes.

2 The term "air monitor" as used here refers to a device jroviding Uniform methods for collecting and analyzing smear a particle collection system, a radiometric measurement system, a continuous recorder, a meter with preset alarm capability, and an samples should be employed. These standardized methods audible alarm system. should be employed over extended periods of time to aid 8.24-3

in cross-comparison of contamination at different times tive clothing. Because it is likely that the radioactive mate-and places and in order to evaluate trends. A dry smear rial on contaminated protective clothing will again become taken from an area of about 100 cm 2 is acceptable to airborne while the clothing is being removed, monitors indicate levels of removable contamination. A diagram of should be available in clothing change areas for workers to each routinely surveyed area should be used for recording survey their clothing before removal and their bodies (partic-survey results. This procedure will provide radiation safety ularly their heads, hands, and other exposed portions) after personnel with a record that will assist in the identification removal of the protective clothing and before leaving the of trends. The surveyor will find it helpful to identify on controlled area. Potentially contaminated clothing should the survey diagram the locations that are smear-tested. not be sent to a laundry that is not specifically authorized to process clothing contaminated with uranium unless the Quantitative measuring instruments used to monitor the clothing has been surveyed and found to have less than 200 adequacy of confinement and contamination control, such disintegrations per minute per 100 cm 2 (9 x 10-7 pCi/cm 2 )

as those used for measuring air samples, and measurements of uranium contamination.

to evaluate uranium contamination of personnel (bioassays),

work areas (smear tests), and equipment should be cali- Individual workers' surveys of themselves need not be brated and checked prior to use each day. The accuracy recorded unless the values in Table 2 are exceeded. However, of the calibration source should be, as a minimum, + 5% of the health physics staff should maintain daily surveillance the stated value and traceable to a primary standard such as to ensure that the workers continue their own personal con-that maintained by the National Bureau of Standards. tamination surveys. Observations during radiation safety surveillance should be recorded.

The regulations in 10 CFR Part 20 do not specify limits for surface contamination. Each applicant may propose and Any personal clothing worn beneath protective clothing justify surface contamination limits allowable before decon- should be surveyed before leaving the controlled area. In tamination is required in each work area. These limits should the event that personal clothing contamination levels exceed be based on the need to avoid transfer of contamination to preselected limits, workers should be instructed to report uncontrolled areas and to maintain exposures as low as is the situation to the health physics office. A member of reasonably achievable. The contamination limits for con- the health physics staff should then survey and supervise trolled areas presented in Table 2 are acceptable to the any necessary decontamination or clothing disposal. The NRC staff and need not be justified by the applicant. applicant may propose and justify personal clothing con-tamination limits; the level 200 disintegrations per minute 1.5 Protective Equipment and Clothing Contamination per 100 cm 2 (9 x 107 pCi/cm 2 ) is acceptable to the NRC Surveys staff and need not be justified by the applicant. Records should be maintained in the manner described above for When it is impracticable to apply process or other en- instances of protective clothing contamination.

gineering controls to limit concentrations of uranium in air below those defined in paragraph 20.203(d)(1)(ii), other For individuals whose work is conducted in controlled precautionary procedures such as increased surveillance, areas with a potential for high surface contamination levels, limitation of working times, or provision of respiratory complete clothing changes are normally provided. In this protective equipment must be used to maintain intake of case, personal clothing should be stored outside the con-uranium by any individual within the limits. When respira- trolled area. Surveys of personal clothing are not necessary tory protective equipment is used to limit the inhalation of in this case if the area in which the clothing is stored is sur-airborne uranium pursuant to paragraph 20.103(b)(2), the veyed in accordance with Regulatory Position C. 1.4 of licensee may make allowance for such use in estimating this guide and if survey results are below the limits adopted exposures of individualsto uranium provided such equipment for in-plant uncontrolled areas. After removal of protective is used as stipulated in Regulatory Guide 8.15, "Acceptable clothing and washing and before donning personal clothing Programs for Respiratory Protection." Licensees are required and leaving the change areas, particular attention should to notify in writing the director of the appropriate Nuclear be paid to surveying the hair, bottoms of the shoes or feet, Regulatory Commission Inspection and Enforcement and the hands.

Regional Office listed in Appendix D to 10 CFR Part 20 at least 30 days before the date that respiratory protective 1.6 Personal Surveys equipment is first used under the provisions of paragraph 20.1 03(b)(2). Individuals whose duties involve work in controlled areas where uranium contamination of body surfaces is probable Individuals working in areas where a potential for skin or should survey all exposed areas of the body after washing clothing contamination exists should wear suitable protec- and before donning personal clothing and leaving the con-8.24-4

trolled area. Skin contamination levels may be proposed ensure that reasonable efforts will be made to eliminate and justified by the applicant. Workers should be required the residual contamination.

to report to the health physics office if there is contamina-tion on the body that exceeds the preselected levels following 1.8 Surveys of Packages Received and Packages Prepared attempts to remove the contamination by soap and water for Shipment washing. Decontamination attempts under the direction of the radiation safety staff or the licensee's medical consult- External radiation surveys and smear tests of external ant should be repeated until (1) such attempts cease to surfaces of packages should be carried out both at the effect significant reductions or (2) such attempts threaten packaging point before being sent to the shipping point and to damage the skin. 3 If the residual contamination does not at the receiving point to avoid unwarranted radiation expo-exceed preselected levels when the decontamination attempts sure and inadvertent contamination of personnel or the are terminated, there should be no further concern because facility. Surveys and labeling must comply with regulatory the contamination would not then present a significant requirements in § § 20.203 and 20.205 of 10 CFR Part 20 ingestion or inhalation hazard. If residual contamination and any specific license conditions. Packages transported exceeds the selected limits, the affected individual should within the plant should also be surveyed and labeled. When be released, but periodic surveys should be made until the practicable, materials should be transferred by carts, con-limits are no longer exceeded. Complete records should be veyers, or other mechanical equipment rather than by hand-maintained of each incident of this nature. carrying. Packages (particularly pails or other containers containing powder or other finely divided material) should Because of the potential for intake of uranium in various not be opened until the packages have been placed in an chemical and physical forms, screening by means of nasal appropriately exhausted facility such as a hood or glove swabs and bioassay by means of urinalysis, fecal analysis, box. Packages should not be released for shipment or and in vivo counting should be performed if, on the basis of transfer unless external radiation and contamination levels air sampling data, accident, equipment failure, etc., there is are within the limits of the Department of Transportation reason to believe that an individual might have taken regulations.

uranium into his or her body. Minimum acceptable criteria, including numerical guidance on the initiation, selection, 1.9 Checks on Posting of Caution Signs, Labels, Signals, frequency, and interpretation of results for such programs, Controls, and Notices to Employees are provided in Regulatory Guide 8.11, "Application of Bioassay for Uranium." The health physics staff should survey to ensure that signs, labels, signals, other access controls, required notices 1.7 Surveys of Equipment, Premises, or Scrap Prior to to employees, copies of licenses, and other items are prop-Release for Uncontrolled Use erly posted, legible, and operative as required by 10 CFR Parts 19 and 20 or specific license conditions. Criticality Surface contamination surveys should be conducted and.air monitor alarms should be tested monthly unless the for both removable and total contamination prior to the licensee provides justification for testing at less frequent release of potentially contaminated premises, equipment, or intervals. Any failure of such devices to perform as intended scrap from controlled to uncontrolled areas and use. If con- should be promptly corrected.

tamination is detected or is known to have been covered, reasonable efforts should be made to eliminate the contami- 1.10 Leak-Tests of Sources nation, i.e., decontamination procedures should be repeated until additional efforts do not significantly reduce contami- Leak-testing of sources such as those used in instrument nation levels. If the value of the items involved does not calibration and quality control procedures must be carried justify this level of effort, the items should be disposed of out in accordance with the terms and conditions of the as radioactive waste or limited to use inside the controlled applicable specific license.

area. The applicant may propose and justify total and removable contamination levels higher than those specified 1.11 Calibration of Radiation Safety Instruments in the license for uncontrolled use. Such proposals should Portable survey instruments should be placed on a routine maintenance and calibration program that will ensure that properly calibrated and operable survey instruments are 3

Decontamination attempts without a medical consultant present available at all times for use by the health physics staff.

should be restricted to approved decontamination procedures agreed upon by the licensee and the licensee's medical consultant. If such attempts do not reduce the contamination to acceptable levels, the An adequate calibration of survey instruments cannot be aid of a physician should be obtained. performed solely with built-in check sources. Electronic cali-8.24-5

brations that do not involve a source of radiation also will tional surveys for airborne uranium, contamination of not determine the proper functioning and response of all personnel and equipment, etc., should be made during and components of an instrument. However, an initial calibra- after glove changes and any other operations during which tion with a radiation source and periodic tests using elec- the integrity of the system may be lost. In addition to these tronic input signals may be considered adequate for high surveys, each enclosure should be equipped with a device ranges that are not used routinely. that indicates the flow rate, pressure drop, or negative pressure in the enclosure. Workers should be instructed to Daily or other frequent checks of survey instruments check on these devices and to notify the health physics should be supplemented every six months with a calibration staff promptly upon indication of flow rates below preset of each instrument at two points separated by at least 50 levels.

percent of each linear scale that is used routinely or with a calibration at one point near the midpoint of each decade 1.13 Surveys of In-Plant Uncontrolled Areas on logarithmic scales that are used routinely. Digital readout instruments with either manual or automatic scale switching Uncontrolled areas inside the plant should be surveyed should be calibrated in the same manner as are linear read- periodically to ensure that uranium is adequately confined out instruments. Digital readout instruments without scale in the controlled areas. Procedures should be established for switching should be calibrated in the same manner as are the movement through corridors or other uncontrolled areas logarithmic readout instruments. Survey instruments should of the plant of uranium in any form that is capable of con-also be calibrated following repair. A survey instrument may taminating surfaces or of dispersal in air. Acceptable survey be considered properly calibrated when the instrument frequencies are discussed in Regulatory Position C.2; results readings are within + 10 percent of the calculated or known should be recorded as described in Regulatory Position C.3.

values for each point checked. Readings within + 20 percent With the exception of lunch rooms, cafeterias, snack bars, are considered acceptable if a calibration chart or graph is and vending machine areas, random smear testing of floors prepared and attached to the instrument. alone is adequate for most uncontrolled areas. In lunch rooms, cafeterias, snack bars, and vending machine areas, 1.12 Ventilation Surveys furniture and vending equipment as well as floors should be surveyed. If such surveys reveal that contamination has Health physics personnel should conduct surveys monthly been transferred out of the controlled areas, immediate to determine that the velocity of air flow at the entrance of corrective action should be taken to eliminate such trans-all hoods or other exhausted enclosures and close-capture fers and to decontaminate the uncontrolled areas. Also, points is adequate to preclude escape of airborne uranium the uncontrolled areas should be surveyed more frequently (considering density and particle size of the materials (e.g., daily or weekly) after contamination has been found present) and to minimize the potential for intake by until a trend of negative results is again established. The workers. Such measurements should be made using a prop- applicant may propose and justify permissible contamina-erly calibrated thermoanemometer or velometer to deter- tion levels for in-plant uncontrolled areas. The limits mine whether or not the air flow has been reduced to given in Table 2 are acceptable to the NRC staff and need unacceptable levels by filter loading, malfunction of exhaust not be justified by the applicant.

fans, etc. The average face velocity for a hood used for special nuclear material with the sash in the operating posi- 1.14 Surveillance tion and an opening in a special enclosure should be 150 ft/

min (45 m/min) as determined from at least five different The term "surveillance" as used in this guide, refers to measurement points. In addition to these surveys, each observations of working conditions in and around the plant enclosure should be equipped with manometers or other made by the health physics staff who perform the routine indicators of the pressure drop across filters to provide radiation and contamination surveys. Such surveillance is early indication of a reduction in air flow; the readings of considered by the NRC staff to be one of the most impor-such devices should be checked during each shift or more tant aspects of a protection program. There should be a pre-frequently for operations where high loading rates may conceived surveillance plan through which health physics occur. Corrective action should be taken as soon as possible personnel acquire and maintain detailed knowledge of each when the air flow is found to be deficient. Work should be operation as necessary to permit (I) the identification of terminated if the average face velocity falls below 100 ft/min ways to prevent or minimize occupational exposures, (2) the (30 m/min). selection of appropriate times for making health physics measurements, and (3) adequate preparation for action to Surveys should be made of the negative pressure main- be taken in the event of breakdown of process equipment tained inside glove boxes or other closed systems. Addi- or other emergency conditions. Health physics personnel 8.24-6

who are responsible for performing surveys should be suffi- disintegrations per unit time per milliliter or microcuries ciently familiar with each activity to recognize potential per milliliter. Surface contamination measurement results hazards so that precautions can be taken to minimize expo- should be recorded in disintegrations per unit time per 100 sures. Knowledge of procedures within each activity is square centimeters or in microcuries per square centimeter.

essential to the selection of appropriate times for performing The intake of radioactive material should be recorded in health physics measurements. terms of microcuries (micrograms may be used for U-234, U-235, and U-238) and percentage of the applicable limit.

2. FREQUENCY OF SURVEYS Methods used to calculate intake quantities from bioassay data should be specifically referenced or documented in the The frequency of routine surveys depends on the nature exposed individual's record. If specific information on the of the work being conducted, the quantities of material uranium compounds involved and their behavior in an indi-being processed, and the specific protective facilities, equip- vidual is known, such information may be used and docu-ment, and procedures used to protect the workers from mented in the exposed individual's record.

external radiation and the intake of uranium. For example, the nature and frequency of surveys appropriate for a plant Records retention requirements are given in the regula-in which all or a large portion of the work is conducted tions cited above. Paragraph 20.401(c)(2) requires that entirely within closed systems are quite different from survey records be preserved for two years, except that those conducted in plants having only hoods, exhausted (1) records of air monitoring, bioassay by urinalysis, fecal enclosures, or close-capture exhaust systems. analysis, whole body or in vivo counting, etc., used to determine the intake of an individual in compliance with Generally, surveys should be performed prior to the oper- § 20.103, (2) in the absence of personnel monitoring data, ation of the plant in order to establish a baseline of back- records of surveys to determine external radiation dose, ground radiation levels and radioactivity from natural and (3) results of surveys used to evaluate the release of sources. These baseline surveys should be performed under radioactive effluents to the environment (not treated in various conditions to be expected during routine plant this regulatory guide) are to be maintained until the NRC operation. Surveys should be conducted during test opera- authorizes their disposition. Note that additional informa-tion of any new process or protective equipment, during tion such as occupancy time may be essential to the estima-significant changes in input materials or work load, and tion of dose from survey data or the estimation of intake during routine plant operations with all potentially involved from data on air concentrations.

persons present and carrying out their functions. Routine and repetitive surveys are necessary to control the location Records may be maintained in logbooks or on special of material within process equipment and handling systems forms if they are clear, legible, understandable, authenti-and to ensure the continued integrity of protective equip- cated by authorized personnel, and contain all of the infor-ment and the adequacy of procedures. The survey program mation required. The signature of the person making the should be capable of monitoring the continuing adequacy record and the data should be on the same page immediately of containment and control of the materials involved in following each record entry. Either the original or a repro-the entire plant operation- Although the frequencies of duced copy or microform (duly authenticated) may be routine surveys depend on many factors and should be maintained to meet the storage requirements of § 20.401.

designed for the specific operations and facilities involved, minimum frequencies acceptable to the NRC staff as meeting the requirements of § 20.201 of 10 CFR Part 20 D. IMPLEMENTATION are given in Table 1.

The purpose of this section is to provide information to

3. RECORDS OF SURVEYS applicants and licensees regarding the NRC staff's plan for using this regulatory guide. This guide reflects practices Reference should be made to § 20.401 of 10 CFR Part currently acceptable to the NRC staff. Except in those 20, § 40.61 of 10 CFR Part 40, and paragraph 70.32(b)(5) cases in which the applicant or licensee proposes alternative of 10 CFR Part 70 for recordkeeping requirements regard- practices or methods for complying with specified portions ing surveys. Section 20.401 requires that the licensee main- of the Commission's regulations, the practices or methods tain records in the same units used in 10 CFR Part 20. Thus described herein will be used as a basis for evaluating appli-external exposure rates should be recorded in estimated cations for specific licenses for enriched uranium processing maximum dose equivalent units, rem or millirem, to relevant and fabrication of uranium fuel or (in conjunction with parts of the body as specified in § 20.101 of 10 CFR Part inspection of performance) for evaluating survey programs

20. Air concentrations should be recorded in terms of established by licensees.

8.24-7

TABLE 1 SURVEY FREQUENCIES External Removable Radiation Surface Contamination Plant Areas Surveys Air Sampling Surveys Uranium receiving, warehousing, Monthly Continuous air sampling; samples changed Monthly and following shipping weekly and following any indication of any indication of release release leading to airborne concentrations of uranium.

Active processing areas UF6 Monthly Continuous air sampling;* samples changed Weekly and following vaporization, UF 6 -UO2 conver- each shift, following any change in equip- any indication of release sion, chemical processing, scrap ment or process control, and following recovery, powder processing, rod detection of any event that may have loading, decontamination, waste released uranium, i.e., leakage (valves, processing, change rooms pipes, tanks, trays), spillage, or blockage of process equipment (conveyors, elevators, hoppers).

Chemical-metallurgical Monthly Continuous air sampling; samples changed Weekly laboratory each shift.

Fuel assembly, inspection, storage Monthly Continuous sampling; samples changed Monthly weekly.

Lunch rooms, cafeterias, snack Quarterly - Daily bars, vending machine areas See Regulatory Position C.1.3.

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TABLE 2 LIMITS FOR REMOVABLE SURFACE CONTAMINATION (Alpha Activity)

IN ENRICHED URANIUM PROCESSING AND LWR FUEL FABRICATION PLANTS Limit Item DPM/100 cm2 MCi/cm2 Controlled areas 5,000 2.3 x 10-S

• Protective clothing worn only in controlled areas 1,000 4.5 x 106 Uncontrolled areas onsite 200 9 x 107

• Personal clothing worn outside restricted areas 200 9 x 10 7 Skin 0**

Determined by direct measurement.

See Regulatory Position C.1.6 and footnote 3.

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REFERENCES*

1. National Commission on Radiological Protection 6. IAEA Safety Series No. 1, "Safe Handling of Radio-(NCRP) Report No. 8, "Control and Removal of nuclides," 1973 Edition, Code of Practice Sponsored Radioactive Contamination in Laboratories," December by the International Atomic Energy Agency (IAEA) 15, 1951. and the World Health Organization (WHO), 1973.

2. NCRP Report No. 57, "Instrumentation and Monitoring 7. IAEA Technical Report Series No. 133, "Handbook Methods for Radiation Protection," May 1, 1978. on Calibration of Radiation Protection Monitoring Instruments," 1971.

3. NCRP Report No. 58, "A Handbook of Radioactivity Measurements Procedures," November 1, 1978.

8. International Commission on Radiological Protection

4. International Atomic Energy Agency (IAEA) Technical (ICRP) Publication 12, "General Principles of Monitor-Report Series No. 120, "Monitoring of Radioactive ing for Radiation Protection of Workers," Pergamon Contamination on Surfaces," 1970. Press, 1969.

5. IAEA Safety Series No. 38, "Radiation Protection Pro-cedures," 1973. 9. Diegl, H., "Guidelines for Determining Frequency of Wipe Samples," Health Physics Operatibnal Monitor-ing, Vol. 1, C. A. Willis and J. S. Handloser, Eds.,

Gordon and Breach, New York, 1972.

IAEA Reports may be obtained from UNIPUB, Inc., P.O. Box 433, New York, N.Y. 10016. NCRP Reports may be obtained from 10. Sommers, J. F., "Sensitivity of G-M and Ion Chamber NCP Publications, P.O. Box 4867, Washington, D.C. 20014. ICRP Reports may be obtained from Pergamon Press, Maxwell House, Beta-Gamma Survey Instruments," Health Physics 28, Fairview Park, Elmsford, New York 10523. 755, 1975.

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