ML20211B421
| ML20211B421 | |
| Person / Time | |
|---|---|
| Issue date: | 05/31/1986 |
| From: | NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | |
| References | |
| TASK-CE-309-4, TASK-RE REGGD-03.056, REGGD-3.056, NUDOCS 8606110645 | |
| Download: ML20211B421 (12) | |
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[*% U.S. NUCLEAR RECULATCRY COMMISSlHN May 1sse r t v J
%f) REGULATORY GU DE
+ 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 A. INTRODUCTION information on the proposed equipment, facilities, and procedures at the installation. This information is used by Regulations applicable to uranium milling are contained the NRC to determine whether the applicant's proposed in 10 CFR Part 20," Standards for Protection Against Radi- equipment, facilities, and procedures are adequate to protect ation," and in 10 CFR Part 40, " Domestic Licensing of the health and safety of the public and and to determine if Source hf aterial." they will significantly affect the quality of the environment.
Calculations by the NRC of the environmentalimpact from Paragraph 20.l(c) of 10 CFR Part 20 states that licensees the proposed uranium milling operations are based on the should make every reasonable effort to keep radiation estimated rate of production of radioactive airborne partic-exposures, as well as releases of radioactive material to ulates adjusted to reflect the removal efficiency of the unrestricted areas, as low as is reasonably achievable. emission control devices installed in the plant ventilation Paragraph 20.105(c)of 10 CFR Part 20 requires that licens- systems. This requires reliable information on the efficiency ces engaged in uranium fuel cycle operations subject to of these devices. It also requires reliable inf'ormation on the the provisions of 40 CFR Part 190," Environmental Radia- production of airborne radioactive particulates during the tion Protection Standards for Nuclear Power Operations," proposed operations.
comply with that part. Part 190 of Title 40 requires that the maximum annual radiation dose to individual members Section 40.65 of 10 CFR Part 40 requires milloperators
) of the public resulting from fuel cycle operations be lim- to submit semiannual reports to the NRC specifying the
( / ited to 25 millirems to the whole body and to all organs quantity of each of the principal radionuclides released to except the thyroid, which must be limited to 75 millirems. unrestricted areas in gaseous effluents. This information Criterion 8 of Appendix A to 10 CFR Part 40 requires that may be used by the NRC to estimate maximum potential milling operations be conducted so that all airborne efflu- annual radiation doses to the public resulting from effluent ent releases are reduced to levels as low as is reasonably releases and thereby determine compliance with paragraphs achievable. 20.l(c) and 20.105(c) of 10 CFR Part 20 and with Crite-rion 8 of Appendix A to 10 CFR Part 40.The quantity of Air in the immediate vicinity of such uranium milling radionuclides released is based on scheduled sampling of operations as ore crushing, ore griiding,and yellowcz ke dry- effluents discharged into exhaust stacks. The reliability of ing and packaging frequently cor tains radioactive materials these data for estimating radiation sxposures depends on in excess of that permissible for release to unrestricted maintaining uniform operation of the emission control areas. Emission control devices are installed in ventila: ion devices during the reporting time interval because these systems of uranium mills to limit releases of these radio- effluents are not continuously sampled.
active raaterials to the environment.
All emission control devices used in uranium mill ventila.
General guidance for filing an application for an NRC tion systems need to perform reliably under expected oper-source material license authorizing uranium milling opera- ating conditions to meet the objectives discussed above.This 3 tions is provided in i 40.31 of 10 CFR Part 40. An appli- guide describes procedures acceptable to the NRC staff for cant for a new license or renewal of an ex. sting license for a designing, testing, operating, and maintaining these emission uranium mill is required by 5 40.3I to provide detailed control devices to ensure the reliability of their performance.
, USNRC REGULATORY GUIDES The guides e's issued in the following ten brosd cevisions:
Regulatory Guldes are issued to describe and make available to the H Q p ific par s of eC miss$o s reg I tions, t de n a e h e earch d Test Reactors r p rtation b niques used by the staff in evaluating specific roblems or post
- 3. Fuels and Materials Facilities 8. Occupational Health
- N ides er no ub It s or gu at on$, and o plance N them is not required. Methods and solutions ditforent from tnose set
. a r al an Pr tion Id. Gen 1
' * ' (D Undings req'u"IsNe* oYcNinuaNo't a'Yer'nSt or license by the Commission N tU '. ass'u* r Coples of Issued guldes may be purchased from the Government g v ging office at h cgn,t G prgce info,rma,tgg grey g Thin gulde was issued afterconsideration of comments received from Documents, u.s. Government printing olfice, post office son 00m
/ the public. Comments and suggestions for improvements in these 31082, Washlagton, DC 20013 7082, telephone (202)275 2060 or Old I
guides are encouraged at all times, and guides will be revised, as appropelate, to accommodate comments and to reflect new informa-(202)275 2171. qa g n issued auides may also be purchased from the National Technical 4 O Written commente may be submitted to the Rules and Procedures information serv 6ce on a standing order basis. Detalis on tnis Om .
Branch, DRR ADM, U.S. Nuclear Regulatory Commiss.on, service may be obtained by writing NTIS, 5285 Port Royal Road, O Q t']
Washington, Od 20555. Springfield, V A 22161. _ Q) n, Q
Any inf;rm: tion collection retivities m:ntioned in ta 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 operatint consistently near peak efficiency. When under OMB Clearance Nos. 3150-0014 and 31504020, checks indicate that the equipment is not operating with-respectively, 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 concentraang 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 (ALAR A). The primary means of systems at which operating parameters on emission con-accomplishing this is the control of emissions at the trol devices may exceed acceptable limits could prevent purce. 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- i in yellowcake drying and packaging areas. These sources mit continuous operation during repair and maintenance are generally controlled by separate 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 atmosphere through local exhaust stacks. operation of these devices so that correctiv. .etion 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 updating to reflect actual in-pt.snt cf the contaminant to be removed, and conditions of ex perience, equipment manufacturers' guidelines, and the air stream all have a bearing on the device selected NRC guidance. For example, a preventive maintenance for any given application. Emission control devices used program can consist of the equipment supplier's recom-at ore crushing and grinding operations include bag or mendations supplemented by provisions derived from the fiber filters (baghouses), orifice or baffle scrubbers, and licensee's own routine inspection and maintenance wet impingement scrubbers. Water spray systems are records.
also used at these operations to minimit.e the generation of dust. Wet impingement scrubbers or venturi scrubbers The key to proper maintenance of emission control are generally employed at yellowcake drying and packag- devices is frequent inspection. It is important that a ing areas. regular program of inspection be established and followed and records be kept of all inspections and the resulting All emission control devices used in a uranium mill maintenance. Inspection intervals will depend on the ventilation system need to be designed for rehable type of emission control device, the manufacturer's performance under the expected operating conditions. recommendation, and the process area where the unit is initial testing and prcper maintenance are primary installed. These inspections need to be performed as factors in ensuring the reliabihty of these comp (ments. frequently as experience shows to be necessary but not Periodic testing during operation to verify the efficiency less than annually.
of thew component s is another important means of ensuring rehabihty. !!uilt-in features that will facilitate convenient in place testing of these devices are important Considerable maintenance time can be expended on l in ventdation system design. trouble shooting and correction of malfunctions of emis-sion control devices. The abihty to locate and correct -
E mission control devices used in a uranium mill malfunctioning components of these devices requires a ventilation system need to be sufficiently instrumented thorough understanding of the system.
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l Throughout th3 manufacturing industry, there tre signil and alert mill operators when prescribed differ 1ntiil-many models of each type emission control device used pressure ranges are exceeded. Lower differential pressures at uranium mills. These models range in size in order indicate potential deficiencies such as damaged filters or jgS to meet the different air capacity needs at the mdis. In other air bypass channels that should be corrected.
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} addition, some design features of each manufacturer are Ifigher differential pessures indicate that cleaning opera-
'Q unique. Accordingly, the specific design and the testing, operating, and maintenance procedures for each model tions are inadequate. This can be corrected by increasing the frequency of the automatic cleaning cycle through are beyond the scope of this guide. General guidance is adjustment of the differential-pressure switch or timer of presented, however, for each type of emission control the baghouse installation.
device based on typical models in present day use.
Background information for this guidance can be found 1.2 Wet Scrubbers in the Bibliography. The licensee may substitute proce-dures based on specific operating parameters of the Wet scrubbers remove particulates from a gas stream model in use at the facility for those described in this by effecting intimate contact between the gas stream guide, and a scrubbing liquor, usually water. The basic opera-tions that take place within a wet scrubber are (1)
I. DESIGN AND OPERATION saturation of the incoming gas, (2) contacting and capture of the particulates in the scrubbing liquor, and 1.1 Bag or Fabric Filters (Baghouses) (3) separating the entrained particulate-laden liquid from the gas stream. The basic types of wet scrubbers are Bag or fabric filters, usually in the form of baghouses, distinguished by the mechanisms used for transfer of remove particulates from a gas stream by filtering the particulates from the gas stream to the liquid stream.
airborne particulates (by impaction or diffusion) through Most scrubber systems require some type of treatment a porous flexible fabric made of a woven or felted and disposal of the particulate-laden scrubbing liquor, material. These collected particles form a structure of their own, supported by the filter, and have the ability Several water spray systems may be used in wet to intercept and retain other particles. The increase in scrubber operations. Water from the main water spray retention efficiency is accompanied by an increase in system is directed either into a screen or throat to pressure drop through the filter. The baghouses are contact the particulate laden gas stream, in applications equipped with one of several automatic cleaning mecha- where inlet gas temperatures are inordinately high, pre-nisms for periodically dislodging collected material from conditioning of the incoming gas to the scrubber may filter components to prevent excessive resistance to the be necessary to provide adequate humidity and thereby gas flow (i.e., excessive pressure drop) that would i
' maintain particulate collection efficiency. This may be otherwise develop. The dishidged material settles in accomplished by use of an auxiliary water spray system storage hoppers before the filter components are placed upstream of the scrubber particulate scavengmg area.
back on stream. The automatic cleaning cycle can be Where particulate buildup is likely to occur in the initiated by either a differential pressure switch or a entrainment separator, a wash system may be necessary tirner, which may be interlocked with the main fan to avoid this condition. The wash system is usually motor for the baghouse. composed of low-pressure spray nonles using recycled scrubbing liquor or fresh water for cleansing.
The cleaning mechanisms employed in baghouses are based on either mechanical shaking of the filter compo. Orifice, wet impingement, or venturi wet scrubbers nents or pneumatic vibration of these components are generally used in uranium mill ventilation systems, by high-pressure air applied in reverse flow, reverse jet, in orifice type wet scrubbers, the gas stream is made to or reverse pulse modes. The effectiveness of these impinge upon a surface of scrubbing water and is then compressed air systems depends on maintaining a suffi- passed through various constrictions where its velocity cient reservoir of compressed air at the pressure speci- may be increased and where greater liquid-particulate
, fied by the baghouse manufacturer, liigher pressures interaction may occur. The gas stream finally discharges than specified could cause failure of the filter fabric, through a chamber section where entrained droplets are 3 while lower pressures can result in poor filtrr cleaning, disengaged. In wet impingement scrubbers, the gas These problems are minimlied by pressure-regulating stream is wetted with water from low pressure spray devices used in the compressed air systems. nonles in the scrubber intet and then passed through perforated plates at high velocity to impinge on baffle The most critical parameter to be observed during plates or vanes where hquid droplets containing partle-I baghouse operation is the pressure drop. Proper operation ulate matter coalesce and drain to a sump. Solid particles of the baghouse requires, at a minimum, maintaining the are washed to the sump by either intermittent or con-differential pressure of this device in the correct range tinuous sprays. Prior to exiting from the scrubber, the specified by the manufacturer. A manometer or a gas stream passes thrcush an entrainment separator to differential-pressure gauge and transmitter are usually remove entrained liquid droplets. In a venturi scrubber,
, g provided for this purpose. This instrumentation is often the gas stream flows through a throattike passage where supplemented by an audible alarm system designed to the gas is accelerated in velocity. The scrubbing liquor is 3.56 3 L
added at or ahead cf the ve: turi throat and is sheared operating problems requiring corr:ctiva maintenance tre into fine droplets by the high velocity gas stream, almost always one of the following: (1) excessive emis-resulting in liquid-particulate interaction. The gas and sions, (2) short filter bag life, and (3) high pressure liquor droplets then pass through a cyclone separator drop. These symptoms may indicate malfunctioning in where entrained droplets containing particulate matter more than one component. For example, high pressure are removed from the gas stream, drop may be attributable to difficulties with the filter bag cleaning mechanism, low compressed air pressure, Although each type of scrubber discussed above has high humidity, weak shaking action, loose filter bag tnique design features, their collection efficiencies are tension or excessive reentrainment of dust. Many other influenced in simdar ways by incremental changes in factors can cause excessive pressure drop, and several certain common operating parameters, principa'ly gas options are usually available for appropriate corrective end liquid flow as well as pressure drop. A decrease in action.
cither the gas or liquid flow rate could result in insuffi-cient gas cleaning. Collection efficiency can also dimin- 2.2 Wet Scrubbers ish if the liquid-to-gas flow rate ratio falls below design values. An increase in pressure drop across the scrubber The major maintenance problems with wet scrubbers will enhance the collection efficiency for the same size are (1) excessive buildup of solids in the wet / dry zones distribution and concentration of particulates in the gas and entrainment separator, (2) plugged water spray noz-cream. Proper operation of these wet scrubbers requires zies, (3) abrasion in .reas of high velocity such as monitoring of these parameters to determine that they throats and orifices, and (4) corrosion on scrubber vessel are within ranges prescribed to ensure equipment perform- internal surfaces. A buildup of solids often occurs ance consistently near optimum collection efficiency. around the wet / dry interfaces of ducts where the gas I.:strumentation used to monitor these pars neters is stream contacts the wetted scrubber housing. Instrumen-often supplemented by audible alarm systems designed tation such as liquid and gas pressure indicators can to signal and alert mill operators of the need for correc- exhibit rapid solids buildup and therefore require regular live action when prescribed operating ranges are exceeded. cleaning to ensure proper system operation and perform-In some cases automatic control systems with interlocks ance. Increased pressure drop, reduced gas flow, and m:y be necessary. For example, the scrubber fan could subsequent system malfunction are all possible conse-be interlocked to shut down in the event of an indica- quences of a buildup of solids in the entrainment tion of water flow failure. These circumstances would separator. Water spray nozzles frequently wear or clog, require suspending particulate-producing processes in the which produces an uneven liquid pattern and requires v:ntilation zone serviced by the scrubber until corrective their replacement. Venturi and irnpingement scrubbers action could be taken or switching to a redundant tend to show signs of abrasion in areas downstream of scrubber unit. gas and liquid acceleration. Corrosion can occur from the high moisture and airborne liquid incident on Daily operational data summaries on baghouse and components, in particular where protective liners may tet scrubber perforruance are useful in providing a con- have deteriorated.
tinuous record of performance of these devices. Other formats that contain equivalent information such as A regular schedule of routine inspection of key com-recorder charts can also be used for this purpose. ponents and operating parameters is an essential ingredi-Criterion 8 of Appendix A to 10 CFR Part 40 requires ent of a maintenance program for ensuring the reliabil- i that checks of all parameters that determine the effi- ity of performance of typical baghouses and wet scrub-ctney of yellowcake stack emission control equipment bers. Examples of some typical maintenance activities operation be made and logged hourly. In addition, data for baghouses and wet scrubbers used at uranium mills from checks made of all operating parameters necessary are presented in Appendices A and D, respectively, to enable timely identification of malfunctions can be These activities are in addition to those procedures of value in ensuring proper operation of baghouses and recommended by manufacturers for routine lubrication, cet scrubbers and in updating preventive maintenance inspection, and replacement of component parts.
programs for these devices to reflect actual operating experience. 3. TESTING To ensure proper selection of emission control de-
- 2. M AINTENANCE vices, it is necessary for potential users to supply manu- ,
Bag or Fabrie Filters (Raghouses) facturers with a list of specifications for the given appli-2.1 cation, including gas flow rates, liquid flow rates (where The frequency of needed maintenance for baghouses scrubbers are under consideration), temperature, pressure, I
c:n be determined from manufacturers' recommendations pressure drop, concentration of particulates, particle size a:d operating experience. In order of decreasing frequen- distribution, emission levels, and collection efficiency.
cy, the principal baghouse components requiring mainte- The manufacturers, in turn, should design and supply nance are (1) filter bags, (2) flow controls, (3) hoppers, these devices based on test data already available for ,
a:d (4) cleanmg mechanisms. Symptoms of potential prototype equipment used under similar circumstances.
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If relevant test data are not available, it is generally 1. DESIGN AND OPERATION advisable for the manufacturer and potential user to run mutually agreed upon pilot plant or prototype tests with in addition to the requirement in Criterion 8 of a gas stream typical of the gas stream to be cleansed to Aprendix A to 10 CFR Part 40 that requires checks to enrare that proper equipment is supplied to meet the be made and logged hourly of all parameters th.:
des. red collection efficiency. After installation of the determine the efficiency of yellowcake stack emission device, it may be tested in place to confirm its particu- control equipment operation, other emission control late removal efficiency. Periodic in-place testing will devices should be sufficiently instrumented to monitor ensure continued effectiveness of the device. In this all operating parameters necessary to enable timely way, reliable data will be available to the licensee for identification of malfunctions. Consideration should be I estimatmg the environmental impact of uranium milling given to centralizing equipment instrumentation and operations before and after the commencement of controls, where feasible, to facilitate case of changing operations. and evaluating operating parameters.
Collection efficiency for baghouses and wet scrubbers Instrumentation may be supplemented by audible used in uranium mills is usually based on inlet and out- alvms that are preset to signal when prescribed operat-let particulate concentrations in a dry gas corrected to ing range limits are exceeded.
standard temperature and pressure. Inlet and outlet par-ticulate concentrations are preferably sampled simultane- Consideration should be given to installation of auto-ously if practicable. The procedure of choice for deter- matic shutdown instrumentation on processes and sys-mination of particulate concentrations is described in tems so that, when operating parameters on emission Method 5, " Determination of Particulate Emissions control devices exceed preset limits, operations would From Stationary Sources," of Appendix A to 40 CFR cease.
h Part 60, " Standards of Performance for New Stationary Sources." In this procedure, particulate matter is with. Equipment used in the emission control system drawn isokinetically from the gas stream and collected should be clearly marked to allow easy identification.
on a glass fiber filter maintained in a prescribed elevated Up to-date system drawings should be available to temperature range. The particulate mass, which includes identify the location of valves and instruments. A rec-
_ any material that conder.ses at or above the filtration ord of system modification or changes should also be
, temperature, is determined gravimetrically after removal available.
of uncombined water, if a preoperational in-place
- b. determination of collection efficiency is desired, a Consideration should be given to keeping records of procedure mutually acceptable to the user and manufac- operating data in order to evaluate system performance turer may be used. and to provide a basis for establishing or modifying a preventive maintenance program.
- 4. QUALITY ASSURANCE Written procedures should be available for equipment Components of uranium mills do not require a operation and for operator actions if malfunctions formal quahty assurance program; however, particular occur. Checkoff lists should be considered for complex quahty assurance requirements may be imposed by the or infrequent modes of operation. Some operational NRC as license conditions if deemed necessary to procedures that may be considered for typical baghouses protect health. A quality assurance program for emission and wet scrubbers used at uranium mills are presented control devices need oaly be an extension of the overall in Appendix C, quahty assurance program usually submitted by an applicant for a heense to ensure that the emission Equipment operators should be instructed in the control devices are designed and the testing, operating, function of each device and its operating characteristics.
and maintenance procedures are implemented to main- They should also be made aware of consequences of tain uniform operation of these devices within prescribed malfunctions and misoperation as well as of corrective ranges under expected operating conditions. measures that may be taken by the operator.
C. HEGULATOFlY POSITION Equipment op ca* ors should be made aware of modi-fications to the equipment, changes in procedures, and Emisuons from milhng operations must be controlled problems encountered during system operation.
so that all airborne effluent releases are reduced to levels as low as is reasonably achievable. An important 2. MAINTENANCE means of accomphshing this is by means of emission control devices in mdl ventilation systems. The deugn A preventive maintenance program should be devel-and the testing, operating, and maintenance procedures oped and implemented to sustain proper equipment for these emission control devices should ensure that performance and to reduce unscheduled repairs. Inspec-these devices are operating consistently near peak opera- tions should be performed at least annually, more tional efficiency, frequently if necesury, on all comparents.
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la the development of the maint: nance progr:m, con- If a preoperational in-place determination of collec-sideration should be given to the type of emission tion efficiency is desired, a procedure mutually accept-control device, the manufacturer's recommendations, and able to the user and manufacturer may be used.
the process at which the unit is installed. This program may require periodic updating to reflect onsite mainte- 4. QUALITY ASSURANCE nance experience.
The overall quality assurance program submitted by Schedules and written procedures should be available an applicant for a license should include provisions for for maintenance work. Maintenance personnel should (1) documentation, review, and evaluation of design, be trained in the implementation of maintenance pro- testing, operating, and maintenance data for emission cedures. They should be trained to recognize the symp- control devices and (2) timely initiation of corrective toms that indicate potential problems, to determine the actions necessary to maintain uniform operation of these cause of the difficulty, and to remedy it with the help, devices within prescribed ranges under expected operat-if necessary, of the manufacturer or other outside ing conditions.
resource.
- 3. TESTING D. IMPLEMENTATION Emission control devices should be tested in place The purpose of this section is to provide information at least annually to verify collection efficiency. Collec- to applicants and licensees regarding the NRC staff's tion efficiency for baghouses and wet scrubbers used in plans for using this regulatory guide, uranium mills should be based on inlet and outlet radioactive particulate concentrations in a dry gas cor-rected to standard temperature and pressure. Inlet and Except in those cases in which an applicant or outlet (radioactive or uranium) particulate concentrations licensee proposes an acceptable alternative method for shouki be sampled simultaneously, if practicable. complying with specified portions of the Commission's regulations, the methods described in this guide will be The test should be performed in accordance with used by the NRC staff in evaluating procedures for Method 5 of Appendix A to 40 CI:R Part 60 or an designing, testing, operating, and maintaining emission acceptable equivalent. control devices used at uranium mills.
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1 BIBLIOGRAPHY American Industrial Hygiene Association, Air Pollution Industrial Gas Cleaning Institute, " Basic Types of Wet Manual Part Il-Control Equipment, American industrial Scrubbers," Publication No. WS-3,1980.*
liygiene Association, Detroit, Mich., pp. 16 18, 46-56, 70-75, 129-135, 1968. Theodore, L., and A. J. Buonicore, Air follution Con-y trol Equipment: Selection Design, Operation and Main-
, American National Standards Institute. " Fundamentals tenance, Prentice-Ilall, Inc., Englewood Cliffs, N.J .,
Governing the Design and Operation of Local Exhaust Chapters 8 and 9,1983.
)
Systems," American National Standard ANSI Z9.21979,
)
Sections 6 and 9, New York, NY,1980. U.S. Environmental Protection Agency, "llandbook-Industrial Guide for Air Pollution Control," EPA-625/
Cross, F. L., and 11. E. liesketh, //andbook for the 678404, Chapter 7,1978.
Operation and Maintenance of Air Pollution Control Equipment, Technomic Publishing Co., Inc., Westport, U.S. Environmental Protection Agency, " Management Conn., Chapters 2 and 6,1975, and Technical Procedures for Operation and Maintenance of Air Pollution Control Equipment," EPA-905/
Industrial Gas Cleaning Institute, " Operation and Main- 2 79402, Sections 3 and 5,1979.
tenance of Fabric Collectors," Publication No. F 3, . A,,usbi from the industrias cas cleanins lastitute, Inc.,
1972.* 700 N. tairren street, Aleaandrea, VA 223:4.
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APPENDIX A TYPICAL MAINTENANCE ACTIVITIES FOR BAGHOUSES 1
COMPONENT ACTIVITIES <
1 Baghouse llousing e Inspect exhaust from filters for visible dust. 4 e Inspect gasketing on filter housing to ensure against leakage.
Compressed Air System e Inspect for air leakage (Iow pressure) and check valves.'
I e Check alignment of air pulse holes with center of bag filters.*
Dust Collection ilopper e inspect for dust and debris buildup in ducts to hopper, e Rod out dust buildup on all accessible hopper surfaces.
e Check operation of the discharge mechanism.
Manometer e inspect for blockage.
Filter Bass e Inspect individual filter bags and attachment hardware.
'ActMtles applicable to pulse or jet baghouses. The remainder are applicable to all baghouses.
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APPENDlX 8 TYPICAL MAINTENANCE ACTIVITIES FOR WET SCRUBBERS COMPONENT ACTIVITIES Scrubber Body e Inspect for wear, particularly in areas downsttram of gas and liquid acceleration.
e Inspect for corrosion on a11 scrubber internal surfaces.
[
o Inspect for excessive buildup,in particularin the wet / dry zone.
Nozzles e inspect for buildup and damage.
Entrainment Separator o Check operation.
e inspect structural supports forintegrity.
l Pumps e Inspect pumps for wear, seal water, packing, and smooth operation.
Instruments e Inspect the condition of allinstruments with regard to solids buildup.
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APPENDIX C TYPICAL OPERATIONAL SURVEILLANCE PROGRAM FOR EMISSION CONTROL DEVICES EMISSION '
CONTROL DEVICE SURVEILLANCE ACTIVITY Baghouses e Monitoring differential pressure. Adjusting timer or differential-pressure switch to adjust frequency of q automatic cleaning cycle as needed.
- Monitoring differential-pressure alarm lights in control area.
- Monitoring compressed air pressure gauge on high-pressure air system.
e Monitoring air flow instrumentation in control area.
Wet Scrubbers e Monitoring differential pressure.
e Monitoring differential-pressure alarm lights in control area.
e Monitoring air flow instrumentation and alarm lights in control area.
- Monitoring water flowmeters.
e Monitoring water pressure alarm lights in control aret, e Monitoring control area process control indicator I lights for possible process shutdown in the event I of water flow failures at preconditioning sprays or at the scrubber, e
3.56 10 1
VALUE/ IMPACT STATEMENT The NRC staff performed a value/ impact assessment May 1985. Comments received from the public and to determine the proper procedural approach for pro- additional NRC staff review have shown no need to viding guidance on designing, testing, operating, and change the value/ impact statement pubhshed with the maintaining emission control devices at uranium mills. proposed regulatory guide. Therefore, the value/ impact
) The assessment resulted in a decision to develop a statement published with the proposed guide is still regulatory guide describing procedures for designing, applicable. A copy of the drsft regulatory guide (identi-
> testing, operating, and maintaining emission control fied by its task number, CE 3094) and its associated devices at uranium mills. The results of this assessment value/ impact statement is available for inspection and h were included in a draft regulatory guide on this sub- copying for a fee at the NRC Public Document Room ject, CE. 309-4, that was issued for public comment in at 1717 il Street NW., Washington, DC.
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