ML20129E560
| ML20129E560 | |
| Person / Time | |
|---|---|
| Issue date: | 05/31/1985 |
| From: | Weinstein M NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | |
| Shared Package | |
| ML20129E564 | List: |
| References | |
| RTR-REGGD-3.056, TASK-CE-309-4, TASK-RE REGGD-03.XXX, REGGD-3.XXX, NUDOCS 8506060535 | |
| Download: ML20129E560 (17) | |
Text
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Pott U.S. NUCLEAR REGULATORY COMMISSION May 1985 y
0FFICE OF NUCLEAR REGULATORY RESEARCH fiivision 3
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Tas'k CE 309-4 e,
DRAFT REGULATORY GUIDE AND VALUE/ IMPACT STATEMENT
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Contact:
M. S. Weinstein (301) 443-7910 i
GENERAL GUIDANCE FOR DESIGNING, TESTING, OPERATING, AND MAINTAINING EMISSION CONTROL DEVICES AT URANIUM MILLS 3
A.
INTRODUCTION h
Regulations applicable to uranium milling are contained in 10 CFR Part 20,
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" Standards for Protection Against Radiation," and in 10..CFR.Part-40, " Domestic h
Licensing of Source Material."
K Paragraph 20.1(c) of 10 CFR Part 20 states that licensees should make every reasonable effort to keep radiation exposures, as well as releases of
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radioactive material to unrestricted areas, as.far below the limits specified in Par-
) as is reasonably achievable. Paragraph 20.105(c) of 10 CFR Part 20 requires that licensees engaged in uranium' fuel cycle operations subject to the provisions of 40 CFR Part 190, " Environmental Radiation Protection Standards for Nuclear Power Operations," comply with that part. Part 190 of Title 40
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requires that the maximum annual radiation dose to individual members of the O
public resulting from fuel cycle operations be limited to 25 millirems to the whole body and to all organs except the thyroid, which must be limited to 75 millirems. Criterion 8 of Appendix'A to 10 CFR Part 40 requires that milling operations be conducted so that all airborne effluent releases are reduced to levels as low as is reasonably achievable.
Air in the immediate vicinity of such uranium milling operations as ore crushing, ore grinding, and yellowcake drying and packaging frequently contains radioactive materials in excess of that permissible for release to unrestricted areas. Emission' control devices are installed in ventilation systems of uranium mills to limit releases of these radioactive materials to the enviroriment.
l This regulatory guide snd the associated valueilmpact statement. ire balng issued in draf t form to involve the public in the early stages of the development of a regulatory positten in this area. They have not recs 4Pd complete staff review snd do not represent an official MRC staff pnsition Puh.ic comunents are being solicited on both drafts the guide (including any implementation schedule) and the value/ impact statement. Comments on the value/ impact statement should be accomp4nied 0" supportino data. Comuments on both desf ts should be sent to the Secretary of the C2mmission. U.S. Nuclear Requistory Coassission washington. 0.C. 2055s. Attention-Docketing and service Granen. by July 8, 1985.
Requests for single copies of draf t q' sides (=nich may be reproduced) ar for placement on an automatic distributt-list for single Coplas of future desft guides in spacffic divisions should be made in wetting ts
.s U.$. Nuclear Regulatory Commission. Washington. 0.C. 20555. Attention: 06 rector.
Olvis6en y Technical [nform4 tion and Occument Control.
8506060535 050531 PDR REQQD 03.XXX R PDR
General guidance for filing an application for an NRC source material license authorizing uranium milling operations is provided in S 40.31 of 10 CFR Part 40. An applicant for a new license or renewal of an existing license for a uranium mill is required by S 40.31 to provide detailed information on the proposed equipment, facilities, and procedures at the installation.
This information is used by the 4RC to determine whether the applicant's proposed equipment, facilities, and procedures are adequate to protect the health and safety of the public and to determine if they will significantly affect the quality of the environment.
Calculations by the NRC of the environmental impact from the proposed uranium milling operations are based on the estimated rate of production of radioactive airborne particulates adjusted to reflect the removal efficiency of the emission control devices installed in the plant ventilation systems.
This requires reliable information on the efficiency of these devices.
It also requires reliable information on the production of airborne radioactive particulates during the proposed operations.
Section 40.65 of 10 CFR Part 40 requires mill operators to submit semi-annual reports to the NRC specifying the quantity of each of the principal radionuclides released to unrestricted areas in gaseous effluents.
This infor-mation may be used by the NRC to estimate maximum potential annual radiation doses to the public resulting from effluent releases and thereby determine compliance with paragraphs 20.1(c) and 20.105(c) of 10 CFR Part 20.
The quantity of radionuclides released is based on scheduled sampling of effluents discharged into exhaust stacks.
The reliability of this data for estimating radiation exposures depends on maintaining uniform operation of the emission control devices during the reporting time interval because these effluents are not continuously sampled.
All emission control devices used in uranium mill ventilation systems need to perform reliably under expected operating conditions to meet the objectives discussed above. This guide describes procedures acceptable to the NRC staff for designing, testing, operating, and maintaining these emission control devices to ensure the reliability of their performance.
Any information collection activities mentioned in this draft regulatory guide are containe1 as requirements in 10 CFR Parts 20 or 40, which provide the regulatory basis for this guide.
The information collection requirements in 10 CFR Parts 20 and 40 have been cleared under OMB Clearance Nos. 3150-0014 and 3150-0020, respectively.
2
B.
DISCUSSION The milling of uranium ores results in the production of airborne particu-lates containing uranium and its daughters in several areas of a typical uranium mill.
These areas encompass (1) ore storage, handling, and crushing; (2) ore grinding, leaching, and concentrating processes; (3) yellowcake precipitation, drying, and packaging; and (4) miscellaneous mill locations such as maintenance shops, laboratories, and general laundries.
Milling operations must be con-ducted so that all airborne effluent releases are reduced to levels as low as is reasonably achievable (ALARA).
The primary means of accomplishing this is the control of emissions at the source.
The most significant sources of radioactive airborne particulates occur in ore handling and crushing areas and in yellowcake drying and packaging areas. These sources are generally controlled by separate ventilation systems in each area that remove these airborne particulates through local hoods, hooded conveyor belts, etc., into emission control devices where they are removed from the air streams.
The cleaned air is then discharged by fans into the atmosphere through local exhaust stacks.
Emission control devices are available in a wide range of designs to meet variations in air cleaning requirements.
Degree of removal required, quantity and characteristics of the contaminant to be removed, and conditions of the air stream all have a bearing on the device selected for any given application.
Emission control devices used at ore crushing and grinding operations include bag or fiber filters (baghouses), orifice or baffle scrubbers, and wet impinge-ment scrubbers.
Water spray systems are also used at these operations to mini-mize the generation of dust. Wet impingement scrubbers or venturi scrubbers are generally employed at yellowcake drying and packaging areas.
All emission control devices used in a uranium mill ventilation system need to be designed for reliable performance under the expected operating condi-tions.
Initial testing and proper maintenance are primary factors in ensuring the reliability of these components.
l'ariodic testing during operation to verify the efficiency of these components is another important means of ensur-ing reliability.
Built-in features that will facilitate convenient in place testing of these devices are important in ventilation system design.
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I Emission control devices used in a uranium mill ventilation system need to be sufficiently instrumented to measure and monitor their operating character-istics.
Frequent checks of all significant operating parameters are necessary I
to determine whether or not conditions are within a range prescribed to ensure that this equipment is operating consistently near peak efficiency.
When checks indicate that the equipment is not operating within this range, it is necessary to take action to restore parameters to the prescribed range.
To ensure that timely actions are taken, instrumentation is often supplemented by audible alarms that are preset to signal when prescribed operating range limits are exceeded. When the required actions cannot be taken without shutdown and repair of this equipment, it will be necessary to suspend milling operations that are the source of the emissions that are being controlled until corrective actions have been implemented.
Suspension of yellowcake drying and packaging operations as soon as practicable under these circumstances is required by Criterion 8 of Appendix A to 10 CFR Part 40.
The installation of automatic shutdown instrumen-tation on processes and systems where operating parameters on emission control devices may exceed acceptable limits could prevent excessive releases that may result from continuous operations under these circumstances, e.g., those asso-ciated with the production of yellowcake.
A preventive maintenance program is important for emission control devices used in uranium mill ventilation systems.
A program designed to identify deficiencies in operation of these devices so that corrective action can be taken to reduce the frequency of off-normal operation can provide a measure of confidence in the operating characteristics of these devices.
This program may require periodic updating to reflect actual in plant experience, equipment manufacturer's guidelines, and NRC guidance.
For example, a preventive main-tenance program can consist of the equipment supplier's recommendations supple-mented by provisions derived from the licensee's own routine inspection and maintenance records.
The key to proper maintenance of emission control devices is frequent inspection.
It is important that a regular program of inspection be estab-lished and followed and records kept of all in3pections and the resulting maintenance.
Inspection intervals will depend on the type of emission control device, the manufacturer's recommendation, and the process area where the unit is installed.
These inspections need to be performed as frequently as experience shows to be necessary but not less than annually.
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Considerable maintenance time can be expended on trouble shooting and correction of malfunctions of emission control devices. The ability to locate and correct malfunctioning components of these devices requires a thorough understanding of the system.
Throughout the manufacturing industry, there are many models for each type of emission control device used at uranium mills. These models range in size in order to meet the different air capacity needs at the mills.
In addition, some design features of each manufacturer are unique. Accordingly, the spe-cific design and the testing, operating, and maintenance procedures for each model are beyond the scope of this guide. General guidance is presented, how-ever, for each type of emission control device based on typical models in present-day use. Background information for this guidance can be found in References 1-8.
The licensee may substitute procedures based on specific operating parameters of the model in use at the facility for those described in this guide, r.
1.
DESIGN AND OPERATION 1.1 Bag or Fabric Filters (Baghouses)
Bag or fabric filters, usually in the form of baghouses, remove particu-lates from a gas stream by filtering the airborne particulates (by impaction or diffusion) through a porous flexible fabric made of a woven or felted material.
These collected particles form a structure of their own, supported by the filter, and have the ability to intercept and retain other particles. The increase in retention efficiency is accompanied by an increase in pressure drop through the filter. The baghouses are equipped with one of several automatic cleaning mechanisms for periodically dislodging collected material from filter components to prevent excessive resistance to the gas flow (i.e., excessive pressure drop) that would otherwise develop.
The dislodged material settles in storage hoppers before the filter components are placed back on stream.
The automatic cleaning cycle can be initiated by either a differential pressure switch or a timer, which may be interlocked with the main fan motor for the baghouse.
The cleaning mechanisms employed in baghouses are based on either mechan-ical shaking of the filter components or pneumatic vibration of these components 5
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by high pressure air applied in reverse flow, reverse jet, or reverse pulse t
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The effectiveness of these compressed air systems depends on maintain-
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ing a sufficient reservoir of comprassed air at the pressure specified by the 3s: 2'.
v baghouse manufacturer.
Higher pressures than specified could cause failure of
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. l the filter fabric, while lower pressures can result in poor filter cleaning.
..js These problems are minimized by pressure regulating devices used in these
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4-The most critical parameter to be observed during baghouse operation is A}.
3 the pressure drop.
Proper operation of the baghouse requires, at a minimum,
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maintaining the differential pressure of this device in the correct range spe-r cified by the manufacturer.
A manometer or a differential pressure gauge and W...
A transmitter are usually provided for this purpose.
This instrumentation is l[-
often supplemented by an audible alarm system designed to signal and alert mill I. f.?
operators when prescribed pressure differential ranges are exceeded.
Lower
.V.'.e differential pressures indicate potential deficiencies such as damaged filters D '. ~ ' ' ~
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or other air bypass channels that should be corrected.
Higher differential
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pressures indicate that cleaning operations are inadequate.
This can be cor-
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rected by increasing the frequency of the automatic cleaning cycle through adjustment of the differential pressure switch or timer of the baghouse
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1 1.2 Wet Scrubbers f-) h %
Wet scrubbers remove particulates from a gas stream by effecting intimate it ' f..? S
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contact between the gas stream and a scrubbing liquor, usually water.
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the incoming gas, (2) contacting and capture of the particulates in the scrub-f.N.w ? ;
bing liquor, and (3) separating the entrained particulate-laden liquid from the
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gas stream.
The basic types of wet scrubbers are distinguished by the mech-
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anisms used for transfer of particulates from the gas stream to the liquid stream.
Most scrubber systems require some type of treatment and disposal of i 9.. "" '4 the particulate-laden scrubbing liquor.
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Several water spray sy' stems may be used in wet scrubber operations. Water 1
.,,y from the main water spray system is directed either into a screen or throat r
to contact the particulate-laden gas stream.
In applications where inlet gas
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_.m '.a j'.,. p;; 45 l ". scrubber may be necessary to provide adequate humidity and thereby maintain f 3 particulate collection efficiency. This may be accomplished by use of an auxiliary water spray system upstream of the scrubber particulate scavenging T.1.j.fs-Where particulate buildup is likely to occur in the entrainment separator, L'g.' area. .y... a wash system may be necessary to avoid this condition. The wash system is g.. usually composed of low pressure spray nozzles using recycled scrubbing liquor ? ~. - - or fresh water for cleansing.
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Orifice, wet impingement, or venturi wet scrubbers are generally used ..[. .,5 in uranium mill ventilation systems. In orifice-type wet scrubbers, the gas L.?.3,.' stream is made to impinge upon a surface of scrubbing water and is then passed )-]'., through various constrictions where its velocity may be increased and where h( greater liquid particulate interaction may occur. The gas stream finally B.t: discharges through a chamber section where entrained droplets are disengaged. . [ 1.... ' In wet impingement scrubbers, the gas stream is wetted with water from low- ,f pressure spray nozzles in the scrubber inlet and then passed through perfo-N 4.' 5 rated plates at high velocity to impinge on baffle plates or vanes where liquid .[ f N ~ droplets containing particulate matter coalesce and drain to a sump. Solid .j i-1 ;p ' ( particles are washed to the sump by either intermittent or continuous sprays. M 'J G. c, Prior to exiting from the scrubber, the gas stream passes through an entrain-gj ? ' ment separator to remove entrained liquid droplets. In a venturi scrubber, l _ > 7,,. J N (.4 f the gas stream flows through a throatlike passage where the gas is accelerated c in velocity. The scrubbing liquor is added at or ahead of the venturi throat f and is sheared into fine droplets by the high-velocity gas stream, resulting in jQh;- I liquid particulate interaction. The gas and liquor droplets then pass through IJl [ a cyclone separator where entrained droplets containing particulate matter are "./{.'... h removed from the gas stream. {.; D j Although each type of scrubber discussed above has unique design features, 7,34 :. I their collection efficiences are influenced in similar ways by incremental [h' j changes.n certain common operating parameters, principally gas and liquid U[ flow as well as pressure drop. A decrease in either the gas or liquid flow 4 I[ rate could result in insufficient gas cleaning. Collection efficiency can b:id also diminish if the liquid-to gas flow rate ratio falls below design values.
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An increase in pressure drop across the scrubber will enhance the collection 4y .g ( 1 efficiency for the same size distribution and concentration of particulates in i ..Q. T the gas stream. Proper operation of these wet scrubbers requires monitoring of these parameters to determine that they are within ranges prescribed to I.[.; j &- Y.. l ', d.' l. L. 7 ./,3 '. ;,3_l :. [,
. ~,:.... -. - ,a, s,. _, i: lli l g 3,'.' ( ensure equipment performance consistently near optimum collection efficiency. I,j Instrumentation used to monitor these parameters is often supplemented by b3Y lU audible alarm systems designed to signal and alert mill operators of the need
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5 for corrective action when prescribed operating ranges are exceeded. In some f,.. ',.? f cases automatic control systems with interlocks may be necessary. For example, .J -1., I the scrubber fan could be interlocked to shut down in the event of an indica- ,.. ) 1. ~ I; tion of water flow failure. These circumstances would require suspending h [ particulate producing processes in the, ventilation zone serviced by the 7 scrubber until corrective action could be taken or switching to a redundant ? scrubber unit. Daily operational data summaries on baghouse and wet scrubber performance . ;- ; : ? s a j are useful in providing a continuous record of performance of these devices. Other formats that contain equivalent information such as recorder charts can .} '.. ; e also be used for this purpose. Criterion 8 of Appendix A to 10 CFR Part 40
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requires that checks of all parameters that determine the efficiency of yellow- ?(jhy 6 cake stack emission control equipment operation be made and logged hourly. In L.i ~/ 4 addition, data from checks made of all operating parameters necessary to enable i.' e timely identification of melfunctions can be of value in ensuring proper opera- '\\ m 7. tion of baghouses and wet scrubbers and in updating preventive maintenance (- }. [- l programs for these devices to reflect actual operating experience. ~~ _ ;{ ~ 2. MAINTENANCE !. b. s-o n. 1 2.1 Bag or Fabric Filters (Baghouses) i i
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.?. n :.s The frequency of needed maintenance for baghouses can be determined from (.
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g f. f: p _ manufacturer's recommendations and operating experience. In order of decreas-ing frequency, the principal baghouse components requiring maintenance are M c -? f g 6 f (1) filter bags, (2) flow controls, (3) hoppers, and (4) cleaning mechanisms. s,' 7 y.l m Symptoms of potential operating problems requiring corrective maintenance are 5 (. 9 [. 7 almost always one of the following: (1) excessive emissions, (2) short filter h_l,l. y bag life, and (3) high pressure drop. These symptoms may indicate malfunc-7.T "... ^#
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tioning in more than one component. For example, high pressure drop may be .[,- Q-attributable to difficulties with the filter bag cleaning mechanism, low M,.J !.l. ; j compressed air pressure, high humidity, weak shaking action, loose filter bag If-h. tension or excessive reentrainment of dust. Many other factors can cause 4 e. 4. c ut 3 Af,',,..O 8 l~ L i .~ 7 m g 1. A .y-
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.m.. ...,-e.<,.. e ... g,y... _. _,... ,,..u., y., J' \\ Q :. - 9.'..r i excessive pressure drop, and several options are usually available for appro-9Q:32.4 E ^ ' - priate corrective action.
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2.2 Wet Scrubbers .' N. ' '. The major problems with wet scrubbers from a maintenance standpoint are $;+ [. ~ ~ (1) excessive buildup of solids in the wet / dry zones and entrainment separator, . ;.~.. ~ (2) plugged water spray nozzles, (3) abrasion in areas of high velocity such as throats and orifices, and (4) corrosion on scrubber vessel internal surfaces. W7 *.. J. ^_ . J ' A buildup of solids often occurs around the wet / dry interfaces of ducts where U,-. the gas stream contacts the wetted scrubber housing. Instrumentation such as j ;r f.. liquid and gas pressure indicators can exhibit rapid solids buildup and there- -[ - (.. fore require regular cleaning to ensure proper system operation and performance. (,, L.i Increased pressure drop, reduced gas flow, and subsequent system malfunction are i'- -.z, all possible consequences of a buildup of solids in the entrainment separator. d.1-f.-[ Water spray nozzles frequently wear or clog, which produces an uneven liquid pattern and requires their replacement. Venturi and impingement scrubbers tend 44 '.. ~1.? ". to show signs of abrasion in areas downstream of gas and liquid acceleration. )[ $l\\ I, Corrosion can occur from the high maisture and airborne liquid incident on y'.~.
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g components, in particular where protective liners may have deteriorated. .J -4 Y; A regular schedule of routine inspection of key components and operating /. [ parameters is an essential ingredient of a maintenance program for ensuring the L. -. - reliability of performance of typical baghouses and wet scrubbers. Examples of (.'. f. 6 some typical maintenance activities for baghouses and wet scrubbers used at
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e ? uranium mills are presented in Appendices A and B, respectively. These activ-7, ' J j ities are in addition to those procedures recommended by manufacturers for routine lubrication, inspection, and replacement of component parts. D .lJ v ?:.5. f 4 3. TESTING h ?e s O To ensure proper selection of emission control devices, it is necessary b f+. 0;' f for potential users to supply manufacturers with a list of specifications for 'y,p' the given application, including gas flow rates, liquid flow rates (where ,.y. -- l scrubbers are under consideration), temperature, pressure, pressure drop, con-d '...Uh. a... centration of particulates, particle size distribution, emission levels, and !.>. J [ collection efficiency. The manufacturers, in turn, should design and supply ih. ' M ) .g{% 9 3 .,.n, .... J.
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.,e _~ ? k i.,..(. g9 s these devices based on test data already available for prototype equipment used ll ~.j, 1.- under similar circumstanc.es. If relevant test data are not available, it is . hgf. generally advisable for the manufacturer and potential user to run mutually L.f y f agreed-upon pilot plant or prototype tests with a gas stream typical of the ?.' G. } gas stream to be cleansed to ensure that proper equipment is supplied to meet Y'I ~' 'J' the desired collection efficiency. After installation of the device, it may .,.3 be tested in place to confirm its particulate removal efficiency. Periodic 'A.1. - in place testing will ensure continued. effectiveness of the device. In this . f. s way, reliable data will be available to the licensee for estimating the environ- .)"= mental impact of uranium milling operations before and after the commencement [ v,,. of operations.
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[" Collection efficiency for baghouses and wet scrubbers used in uranium mills ( is usually based on inlet and outlet particulate concentrations in a dry gas {p. ] corrected to standard temperature and pressure. Inlet and outlet particulate J [/ ~ ' concentrations are preferably sampled simultaneously if practicable. The proce- [ ' '. [ dure of choice for determination of particulate concentrations is described in v'. ~.~.$?. Method 5, " Determination of Pa-ticulate Emissions From Stationary Sources," of fl - [ : Appendix A to 40 CFR Part 60, " Standards of Performance for New Stationary .; :q 'f
- Sources." In this procedure, particulate matter is withdrawn isokinetically I..
k.~ frem the gas stream and colle;ted on a glass fiber filter maintained in a 'I.. prescribed elevated temperature range. The particulate mass, which includes J ~ 7.nv material that condenses at or above the filtration temperature, is deter- .F. c. ' mined gravimetrically after removal of uncombined water. If a preoperational
- j. ' J, in place determination of collection efficiency is desired, a procedure 1; j mutually acceptable to the user and manufacturer may be used.
z.ig 9.y 4. QUALITY ASSURANCE l F.- 1,. ' ,.:: u ? u ~ Components of uranium mills do not require a formal quality assurance N-[. " ~ program; however, particular quality assurance requirements may be imposed by .). .y I the NRC as license conditions if deemed necessary to protect health. A quality E.D.[ ' ' ( assurance program for emission control devices need only be an extension of the [.. ,n. overall quality assurance program usually submitted by an applicant for a license 't to ensure that the emission control devices are designed and the testing, opera-
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ting, and maintenance procedures are implemented to maintain uniform operation [7.]-f I of these devices within prescribed ranges under expected operating conditions. g,: f'p. [..l.' - ll gy Y., p.!.: ',D. 10 l 'C i.. b '. ) ,;. f.. Q. ' ,q. -w
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...}. ~ y C. REGULATORY POSITION I..N - L. j)...' , x Emissions from milling operations must be controlled so that all airborne g 7., ,/ effluent releases are reduced to levels as low as is reasonably achievable. An s = '..' ; important means of accomplishing this is by means of emission control devices 1 in mill ventilation systems. The design and the testing, operating, and main- .; c.. tenance procedures for these emission control devices should ensure that these [;., p devices are operating consistently near peak operational efficiency. .f., 'i w 1. DESIGN AND OPERATION m n.. a:.. z In addition to the requirement in Criterion 8 of Appendix A to 10 CFR , L.. Part 40 that requires checks to be made and logged hourly of all parameters [,;..: that determine the efficiency of yellowcake stack emission control equipment c / 4 operation, other emission control devices should be sufficiently instrumented q.j. r. a .J to monitor all operating parameters necessary to enable timely identification (. }; -t ..; f.; -( j of malfunctions. Consideration should be given to centralizing equipment 'j instrumentation and controls, where feasible, to facilitate ease of changing
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~# and evaluating operating parameters. Instrumentation may be supplemented by audible alarms that are preset to Q:9.s.,. 4.D signal when prescribed operating range limits are exceeded. j.i ' t) .7 ]< Consideration should be given to installation of automatic shutdown 9 .l, f. 1 instrumentation on processes and systems so that, when operating parameters on (1:, ' y. Q '~ g emission control devices exceed preset limits, operations would cease.
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Equipment used in the emission control system should be clearly marked to
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] allow easy identification. System drawings should be available to identify the .. } location of valves and instruments. f ".S e .o 7 .g. Consideration should be g;ven to keeping records of operating data in g; order to evaluate system performance and to provide a basis for establishing .p... ' ~ or modifying a preventive maintenance program.
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fh, Written procedures s'iould be available for equipment operation and for f-l. i. e r i k.; operator actions if malfunctions occur. Checkoff lists should be considered -t y1 for complex or infrequent modes of operation. Some operational procedures ,.,s '.4 that may be considered for typical baghouses and wet scrubbers used at uranium .% s mills are presented in Appendix C. [.{@ ,~.,; " !. ' n;;.
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. -( 7.--. w?. n,.. - r : 7,w.as .v. n. .,v . _ t - '3 y "^ { qy. P;j"- p -T..., ~ l Equipment operators should be instructed in the function of each device S h '-l f - and its operating characteristics. They should also be made aware of conse-j'}, quences of malfunctions and misoperation as well as of corrective measures jb'. b .e - that may be taken by the operator. i 3. '_ Equipment operators should be made aware of modifications to the equip-ment, changes in procedures, and problems encountered during system operation. E # "/\\ f [' - l D 4 2. MAINTENANCE C~' ~. N. ._, [.}' A preventive maintenance program should be developed and implemented to
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. r[ ...; -f.(.T, sustain proper equipment performance and to reduce unscheduled repairs. Inspec-V 4 4... . {1{97 tions should be performed at least annually, more frequently if necessary, on all components. ?..,1f-r In the development of the maintenance program, consideration should be i,.f. i given to the type of emission control device, the manufacturer's recommenda-Q,.c,.,f f tions, and the process at which the unit is installed. This program may require ,c ? [ periodic updating to reflect onsite maintenance experience.
- .(, ' t..l Schecules and written procedures should be available for maintenance work.
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- Maintenance personnel should be trained in the implementation of maintenance
"^; procedures. They should be trained to recognize the symptoms that indicate a YT p potential problems, to determine the cause of the difficulty, and to remedy .s 5 it with the help, if necessary, of the manufacturer or other outside resource. s, 1 n } g. 3. TESTING
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r m. Emission control devices should be tested in place at least annually to . 1. C ...s s-7 verify collection efficiency. Collection efficiency for baghouses and wet lS ' ".;.[/ i.) scrubbers used in uranium mills should be based on inlet and outlet radioactive N3.. - ei particulate concentrations in a dry gn corretad to standard temperature and j U fl q pressure. Inlet and outlet (radioactive or uraniun ) particulate conce. rations . " ' ~ 3 should be sampled simultaneously, if practicable. y-The test should be performed in accordance with Method 5 of Appendix A to ,.-'k l 40 CFR Part 60 or an acceptable equivalent. I <..'.y e If a preopera+ional in place determination of collecticn efficiency is 9.v.',."- R ' s... ( desired, a procedure mutually acceptable to the user and manufacturer may be p ",, % s.. used. ('y . 2 i,.- ),. - g,.
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QUALITY ASSURANCE i - - w ~ i i ' The overall quality assurance program submitted by an applicant for a -.-. ;.~ i. ;.' ' license should include provisions for (1) documentation, review, and evaluation of design, testing, operating, and maintenance data for emission control devices and (2) timely initiation of corrective actions necessary to maintain ,f' 4. ! - uniform operation of these devices within prescribed ranges under expected ~ ' ~ 'J" y-operating conditions. ' L~-. " ' - O. IMPLEMENTATION 4 - 6 ;,. f c -J, :J -- 4; ..j..,.'. The purpose of this section is to provide information to applicants and ?- licensees regarding the NRC staff's plans for using this regulatory guide. This draft guide has been released to encourage public participation in its development. Except in those cases in which an applicant proposes an accept-f -l-} ('.f; able alternative method for complying with specified portions of the Commission's ~ ' J.' -: ~ ^ regulations, the methods to be described in the active guide reflecting public ['.'^";' t comments will be used by the NRC staff in evaluating procedures for designing, l testing, operating, and maintaining emission control devices used at uranium = ' ~ -.'( mills. L., ;. - .g. *. ), -~. ,...x j l . -:.g 1 'll 9 e y ; _. ?,, 3. - k i .;C
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,. v ...,, y e.. c., - m .m,. .... = - .. e ;- .e e... -. u. 2 :4 ( g -r ;- L _ W.n. a. ..- g 1 REFERENCES - y - - e. 9.... .v e,.. 1. L. Theodore and A. J. Buonicore, Air Pollution Control Equipment: ' 4.' Selection, Design, Operation and Maintenance, Prentice-Hall, Inc., Englewood Cliffs, N.J., Chapters 8 and 9, 1983. < ' ~.., 3 - ~ _. -; .g. 2. F. L. Cross and H. E. Hesketh, Handbook for the Operation and Main- $ ' l# - - y.. tenance of Air Pollution Control Equipment, Technomic Publishing Co., 'Y
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4-,.. Inc., Westport, Conn., Chapters 2 and 6, 1975. F7 t m -- ..h 3. U.S. Environmental Protection Agency, " Handbook--Industrial Guide for Air Pollution Control," EPA-625/6-78-004, Chapter 7, 1978. l ', f ,.v.f.'..., s 4. U.S. Environmental Protection Agency, " Management and Technical Procedures j,. for Operation and Maintenance of Air Pollution Control Equipment," J.7.k;.' 5 =.. -j.; EPA-905/2-79-002, Sections 3 and 5, 1979. N'. s ~ 5. Industrial Gas Cleaning Institute, " Operation and Maintenance of Fabric '</,. Collectors," Publication No. F-3, 1972. Available from Industrial Gas Ni d, '.' i Cleaning Institute, Inc., 700 N. Fairfax Street, Alexandria, VA 22314. - " p'. -.i. + -: ;.. f._ l 6. Industrial Gas Cleaning Institute, " Basic Types of Wet Scrubbers," " ] 's i Publication No. WS-3, 1980. Available from Industrial Gas Cleaning
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Institute, Inc., 700 N. Fairfax Street, Alexandria, VA 22314. ..7 -; _ ~ c. g. e 7. American Industrial Hygiene Association, Air Pollution Manual, Part II-- Control Equipment, American Industrial Hygiene Association, Detroit, Mich., h pp. 16-18, 46-56, 70-75, 129-135, 1968. }. 'c * - ] y 8. American National Standards Institute, " Fundamentals Governing the Design ![ 4;1;- and Operation of local Exhaust Systems," American National Standard . v. ., f' j. ANSI Z9.2-1979, Sections 6 and 9, New York, NY, 1980.
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, V - c _ u.:. t W.... 's . ' 3: I TYPICAL MAINTENANCE ACTIVITIES FOR BAGH0USES i.'. s s. .1. COMPONENT ACTIVITIES . ', -i '. "?.~: y., 7- ~:; ) --} L.... a Inspect exhaust from filters for visible dust. Baghouse Housing Inspect gasketing on filter housing to ensure y". against leakage. .':~; g Inspect for air leakage (low pressure) and check D.,. a '4 Compressed Air System valves.* .i e.P;~.. y Check alignment of air pulse holes with center '- jfl.. '.g w....,, i of bag filters.* C t - = -w.-. -,, 7 Dust Collection Hopper Inspect for dust and debris buildup in ducting to _,g hopper. . ; e ?. g Rod out dust buildup on all accessible hopper . [, p -] .N i g-surfaces. .j Check operation of the discharge mechanism. 7-g './.a v.. Inspect for blockage. E c.- r Manometer
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Jh_ g_ ..*v. Inspect individual filter bags and attachment g.) Filter Bags .c. ' e-
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- Activities applicable to pulse or jet baghouses.
The remainder are applicable P ? %.- l to all baghouses. u. s. s- .. 7, ,e 15 (e 0.'. U.1. s .+ .,.) Yf ','.. u.,'f , Q'. .y..W . [,!- ' m.. e. .ie + - n .._n.. _._.m
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L t APPEND] 1 i..,,,. c l. ./-. [. i.;.# ". k
- TY? :A. )A NTENANCE ACTIV 7:IS FOR WET SCRLIIEES
.y 3.* v.: ,. 1 l COMPONENT AGIVITIES p..
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Scrubber Body Inspect fo' wear, particularly 'n areas downstream '[ ' ' ) of gas and liquid acceleration. J ~ Inspect for corrosion on all scrubber internal 2D ~ [ surfaces. .,.k. ; c... Inspect for excessive buildup, in particular in -_..l,.:... !l-l the wet / dry zone. X ? .s k ~_. ...y: dO. i Inspect for buildup and damage. Nozzles E ).:.... Check operation. 1.' * - - 1 Entrainment Separator Inspect structural supports for, integrity.
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..,.x v Inspect pumps for wear, seal water, packing, and f'.*- j Pumps f smooth operation. .. :.. ' i. i' - ? T Inspect the condition of all instruments with Instruments [. regard to solids buildup. q ~ .f4 E ? .I' 9 9 y ( 3 [e *~,. l-s., 9
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. i-1 \\ ...,i ? x ..v ; APPENDIX C . -.M, 'L }l y s TYPICAL OPERATIONAL SURVEILLANCE PROGRAM f?. FOR EMISSION CONTROL DEVICES ~ " ~ l . ~. _ - p y EMISSION SURVEILLANCE ACTIVITY - 4 CONTROL DEVICE ...-;e i- ,1 Baghouses Monitoring differential pressure. Adjusting timer or .?.. .. w'..] differential pressure switch to adjust frequency of auto- =., matic cleaning cycle as needed. g. p.,t s '.-Q 1 : .-., 4 - Monitoring differential pressure alarm lights in control '. 2-I .. _ 'e area. V, 7:. -z..- Monitoring compressed air pressure gauge on high pressure f 7-..
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air system. ..s l Monitoring air flow instrumentation in control area. I.; -.p ,..e Monitoring differential pressure. t" det Scrubbers w... 5 Monitoring differential pressure alarm lights in control %lc '. - -l - area. ...,. I Monitoring air flow instrumentation and alarm lights in s ::.. 3 control area. "..f. - ~ ~ f .z. Monitoring water flowmeters. ,J?. Monitoring water pressure alarm lights in control area. D'> .g .e. Monitoring control area process control indicator lights for [. f.i l possible process shutdown in the event of water flow failures l D.- at preconditioning sprays or at the scrubber. (.h?! y "".g -1, ? :.- .w. 17 2.* n,.
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