U.S. NUCLEAR REGULATORY COMMISSION May 1986 CREGULATORY GUIDE -*0*O OFFICE OF NUCLEAR REGULATORY RESEARCH REGULATORY GUIDE 3.56 (Task CE 309-4) GENERAL GUIDANCE FOR DESIGNING, TESTING, OPERATING, AND MAINTAINING EMISSION CONTROL DEVICES AT URANIUM MILLS equipment, facilities, and A. INTRODUCTION information on the proposed procedures at the installation. This information is used by to determine whether the applicant's proposed Regulations applicable to uranium milling are contained the NRC equipment, facilities, and procedures are adequate to protect in 10 CFR Part 20, "Standards for Protection Against Radi health and safety of the public and and to determine if ation," and in 10 CFR Part 40, "Domestic Licensing of the affect the quality of the environment. Source Material." they will significantly Calculations by the NRC of the environmental impact from uranium milling operations are based on the Paragraph 20.1(c) of 10 CFR Part 20 states that licensees the proposed estimated rate of production of radioactive airborne partic should make every reasonable effort to keep radiation ulates adjusted to reflect the removal efficiency of the exposures, as well as releases of radioactive material to emission control devices installed in the plant ventilation unrestricted areas, as low as is reasonably achievable. reliable information on the efficiency Paragraph 20.105(c) of 10 CFR Part 20 requires that licens systems. This requires of these devices. It also requires reliable information on the ees engaged in uranium fuel cycle operations subject to production of airborne radioactive particulates during the the provisions of 40 CFR Part 190, "Environmental Radia proposed operations. tion Protection Standards for Nuclear Power Operations," comply with that part. Part 190 of Title 40 requires that 40.65 of 10 CFR Part 40 requires mill operators the maximum annual radiation dose to individual members Section submit semiannual reports to the NRC specifying the of the public resulting from fuel cycle operations be lim to quantity of each of the principal radionuclides released to ited to 25 millirems to the whole body and to all organs areas in gaseous effluents. This information except the thyroid, which must be limited to 75 millirems. unrestricted may be used by the NRC to estimate maximum potential Criterion 8 of Appendix A to 10 CFR Part 40 requires that annual radiation doses to the public resulting from effluent milling operations be conducted so that all airborne efflu thereby determine compliance with paragraphs ent releases are reduced to levels as low as is reasonably. releases and Part 20 and with Crite achievable. 20.1(c) and 20.105(c) of 10 CFR rion 8 of Appendix A to 10 CFR Part 40. The quantity of released is based on scheduled sampling of Air in the immediate vicinity of such uranium milling radionuclides into exhaust stacks. The reliability of operations as ore crushing, ore grinding, and yellowcake dry effluents discharged data for estimating radiation exposures depends on ing and packaging frequently contains radioactive materials these maintaining uniform operation of the emission control in excess of that permissible for release to unrestricted reporting time interval because these areas. Emission control devices are installed in ventilation devices during the are not continuously sampled. systems of uranium mills to limit releases of these radio effluents active materials to the environment. All emission control devices used in uranium mill ventila reliably under expected oper General guidance for filing an application for an NRC tion systems need to perform meet the objectives discussed above. This source material license authorizing uranium milling opera ating conditions to to the NRC staff for tions is provided in § 40.31 of 10 CFR Part 40. An appli guide describes procedures acceptable and maintaining these emission cant for a new license or renewal of an existing license for a designing, testing, operating, their performance. uranium mill is required by § 40.31 to provide detailed control devices to ensure the reliability of The guides are issued in the following ten broad divisions: USNRC REGULATORY GUIDES Regulatory Guides are issued to describe and make available to the 1. Power Reactors 6. Products public methods acceptable to the NRC staff of Implementing 2. Research and Test Reactors 7. Transportation specific parts of the Commission's regulations, to delineate tech 3. Fuels and Materials Facilities 8. Occupational Health niques used by the staff in evaluating specific problems or postu 4. Environmental and Siting 9. Antitrust and Financial Review lated accidents or to provide guidance to applicants. Regulatory 5. Materials and Plant Protection 10. General Guides are not substitutes for regulations, and compliance with 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 of Issued guides may be purchased from the Government of a permit or Copies .- findings requisite to the issuance or continuance Printing Office at the current GPO price. Information on current license by the Commission. GPO prices may be obtained by contacting the Superintendent of Printing Office, Post Office Box from Documents, U.S. Government This guide was issued after consideration of comments received 37082, Washington, DC 20013-7082, telephone (202)275-2060 or the public. Comments and suggestions for improvements In these (202)275-2171. guides are encouraged at all times, and guides will be revised, as appropriate, to accommodate comments and to reflect new Informa tion or experience. Issued guides may also be purchased from the National Technical Information Service on a standing order basis. Details on this Written comments may be submitted to the Rules and Procedures service may be obtained by writing NTIS, 5285 Port Royal Road, Branch, DRR, ADM, U.S. Nuclear Regulatory Commission, Springfield, VA 22161. Washington, DC 20555. _ Any information collection activities mentioned in to measure and monitor their operating characteristics. this regulatory guide are contained as requirements in Frequent checks of all significant operating parameters 10 CFR Parts 20 or 40, which provide the regulatory are necessary to determine whether or not conditions are basis for this guide. The information collection require within a range prescribed to ensure that this equipment ments in 10 CFR Parts 20 and 40 have been cleared is operating consistently near peak efficiency. When under OMB Clearance Nos. 3150-0014 and 3150-0020, checks indicate that the equipment is not operating respectively. with in this range, it is necessary to take action to restore parameters to the prescribed range. To ensure that B. DISCUSSION timely actions are taken, instrumentation is often supple mented by audible alarms that are preset to signal The milling of uranium ores results in the produc when prescribed operating range limits are exceeded. tion of airborne particulates containing uranium and its When the required actions cannot be taken without shut daughters in several areas of a typical uranium mill. down and repair of this equipment, it will be necessary These areas encompass (1) ore storage, handling, and to suspend milling operations that are the source of the crushing; (2) ore grinding, leaching, and concentrating emissions until corrective actions have been taken. Crite processes; (3) yellowcake precipitation, drying, and rion 8 of Appendix A to 10 CFR Part 40 requires suspen packaging, and (4) miscellaneous mill locations such as sion of yellowcake drying and packaging operations as maintenance shops, laboratories, and general laundries. soon as practicable when shutdown and repair of the Milling operations must be conducted so that all airborne emission control system is necessary. The installation of effluent releases are reduced to levels as low as is automatic shutdown instrumentation on processes and reasonably achievable (ALARA). The primary means of systems at which operating parameters on emission accomplishing this is the control of emissions con at the trol devices may exceed acceptable source. limits could prevent excessive releases that may result from continuous oper ations under these circumstances, e.g., those associated The most significant sources of radioactive airborne with the production of yellowcake. The installation of particulates occur in ore handling and crushing areas and backup or redundant emission control systems would per in yellowcake drying and packaging areas. These sources mit continuous operation during repair are generally controlled by separate and maintenance ventilation systems of the primary system. in each area that remove these airborne particulates through local hoods, hooded conveyor belts, etc., into A preventive maintenance program is important for emission control devices where they are removed from emission control devices used in uranium mill ventilation the air streams. The cleaned air is then discharged by systems. A program designed to identify deficiencies in fans into the atmosphefe through local exhaust stacks. operation of these devices so that corrective action can be taken to reduce the frequency of off-normal opera Emission control devices are available in a wide range tion can provide a measure of confidence in the operat of designs to meet variations in air cleaning requirements. ing characteristics of these devices. This program may Degree of removal required, quantity and characteristics require periodic