Regulatory Guide 1.52: Difference between revisions

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{{Adams
{{Adams
| number = ML011710176
| number = ML13350A197
| issue date = 06/30/2001
| issue date = 07/31/1976
| title = (Revision 3), Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident Engineered-Safety-Feature Atmosphere Cleanup Systems in Light-Water-Cooled Nuclear Power Plants
| title = Design, Testing, and Maintenance Criteria for Engineered-safety-feature Atmosphere Cleanup System Air Filtration and Adsorption Units of Light-Water-Cooled Nuclear Power Plants
| author name =  
| author name =  
| author affiliation = NRC/RES
| author affiliation = NRC/RES
Line 9: Line 9:
| docket =  
| docket =  
| license number =  
| license number =  
| contact person = Segala J P
| contact person =  
| case reference number = DG-1102
| document report number = RG-1.052, Rev. 1
| document report number = RG-1.052
| document type = Regulatory Guide
| document type = Regulatory Guide
| page count = 22
| page count = 11
}}
}}
{{#Wiki_filter:Regulatory guides are issued to describe and make available to the public such information as methods acceptable to the NRC staff for implementing specific partsof the NRC's  regulations, techniques used by the staff in evaluating specific problems or postulated accidents, and data needed by the NRC staff in its review ofapplications for permits and licenses.  Regulatory guides are not substitutes for regulations, and compliance with them is not required.  Methods and solutions differentfrom those set out in the guides will be acceptable if they provide a basis for the findings requisite to the issuance or continuance of a permit or license by theCommission.This guide was issued after consideration of comments received from the public.  Comments and suggestions for improvements in these guides are encouragedat all times, and guides will be revised, as appropriate, to accommodate comments and to reflect new information or experience.  Written comments may be submittedto the Rules and Directives Branch, ADM, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.  Regulatory guides are issued in ten broad divisions:  1, Power Reactors; 2, Research and Test Reactors; 3, Fuels and Materials Facilities; 4, Environmental and Siting;5, Materials and Plant Protection; 6, Products; 7, Transportation; 8, Occupational Health; 9, Antitrust and Financial Review; and 10, General. Single copies of regulatory guides (which may be reproduced) may be obtained free of charge by writing the Distribution Services Section, U.S. Nuclear RegulatoryCommission, Washington, DC 20555-0001, or by fax to (301)415-2289, or by email to DISTRIBUTION@NRC.GOV.  Electronic copies of this guide are availableon the internet at NRC's home page at <
{{#Wiki_filter:U.S. NUCLEAR REGULATORY  
WWW.NRC.GOV> in the Reference Library under Regulatory Guides and through the Electronic Reading Room, asAccession Number ML011710176, along with other recently issued guides, at the same web site.U.S. NUCLEAR REGULATORY COMMISSION               Revision 3June 2001 REGULATORY
COMMISSION
GUIDEOFFICE OF NUCLEAR REGULATORY RESEARCHREGULATORY GUIDE 1.52(Draft was issued as DG-1102)DESIGN, INSPECTION, AND TESTING CRITERIA FOR AIRFILTRATION AND ADSORPTION UNITS OF POST-ACCIDENTENGINEERED-SAFETY-FEATURE ATMOSPHERE CLEANUPSYSTEMS IN LIGHT-WATER-COOLED NUCLEAR POWER PLANTS
REGULATORY  
GUIDE Revitton 1 July 1976 OFFICE OF STANDARDS
DEVELOPMENT
REGULATORY  
GUIDE 1.52 DESIGN, TESTING, AND MAINTENANCE
CRITERIA FOR ENGINEERED-SAFETY-
FEATURE ATMOSPHERE  
CLEANUP SYSTEM AIR FILTRATION
AND ADSORPTION
UNITS OF LIGHT-WATER-COOLED  
NUCLEAR POWER PLANTS  


==A. INTRODUCTION==
==A. INTRODUCTION==
This guide provides guidance and criteria acceptable to the NRC staff for implementing the NRC'sregulations in Appendix A to 10 CFR Part 50 with regard to the design, inspection, and testing of air filtration and iodine adsorption units of engineered-safety-feature (ESF) atmosphere cleanup systems in light-water-cooled nuclear power plants.  For the purposes of this guide, ESF atmosphere cleanup systems are those systems that are credited in the licensee's current design basis accident analysis, as described in the Safety Analysis Report (SAR).  This guide addresses ESF atmosphere cleanup systems, including the various components and ductwork, in the postulated design basis accident (DBA) environment. In Appendix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50,"Domestic Licensing of Production and Utilization Facilities," General Design Criteria 41, 42, and 43 require that containment atmosphere cleanup systems be provided as necessary to reduce the amount of radioactive material released to the environment following a postulated DBA.  They also require that these  
General Design Criteria 41. 42, and 43 of Appendix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50, "Licensing of Production and Utilization Facilities," require that containment atmos-phere cleanup systems be provided as necessary to reduce the amount of radioactive material released to the environment following a postulated design basis accident (DBA) and that these systems be designed to permit appropriate periodic inspection and testing to ensure their integrity, capability, and operability.
1.52-2systems be designed to permit appropriate periodic inspection and testing to ensure their integrity,capability, and operability.General Design Criterion 61 of Appendix A to 10 CFR Part 50 requires that fuel storageand handling systems, radioactive waste systems, and other systems that may contain radioactivity be designed to ensure adequate safety under normal and postulated accident conditions and that they be designed with appropriate containment, confinement, and filtering systems.  General Design Criterion 19 requires that adequate radiation protection be provided to permit access to and occupancy of the control room under accident conditions and for the duration of the accident without personnel radiation exposures in excess of 5 rem to the whole body, or its equivalent to any part of the body. Nuclear power plants are required by 10 CFR Part 100, "Reactor Site Criteria,"  to be sitedso that radiological doses from normal and postulated accidents are kept acceptably low.  A
footnote to 10 CFR 100.11 states that the fission product release assumed in the plant design should be based on a major accident involving substantial core damage with subsequent release of appreciable quantities of fission products.  According to 10 CFR 50.67, an application to revise a licensee's current accident source term must contain an evaluation of the consequences of applicable design basis accidents previously analyzed in the Safety Analysis Report.  This guide does not apply to atmosphere cleanup systems designed to collect airborneradioactive materials during normal plant operation, including anticipated operational occurrences.


Regulatory Guide 1.140, "Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal Atmosphere Cleanup Systems in Light-Water-Cooled Nuclear Power Plants," provides guidance for these systems. The guidance and criteria presented in this guide are not mandatory and licensees maychoose not to change their licensing basis. Methods and solutions different from those set out in this guide will be acceptable when an applicant or licensee proposes an acceptable alternative method for complying with the specified portions of the NRC's regulations.The information collections contained in this regulatory guide are covered by therequirements of 10 CFR Part 50, which were approved by the Office of Management and Budget, approval number 3150-3011. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not
General Design Criterion
61 of Appendix A to Part 50 requires that fuel storage and handling systems, radioactive waste systems, and other systems that may contain radioactivity be designed to ensure adequate safety under normal and postulated accident conditions and that they be designed with appropriate  confinement, and filtering systems. General Design Criterion
19 requires that adequate radit'ion protection be provided to permit access to and occusaucy of the control room under accident conditions and for the duration of the accident without personnel radiation exposures in excess of 5 I.futo the whole body.This guide pres!"4 nertods acceptable to the NRC staff for implernr-ting" e Commission's regulations in Appendix A, tiO CFl Part 50 with regard to the design, te .g, afti imilinance criteria for air filtration and ada T atmosphere cleanup systems in light-water- ed nuclear power plants. This guide applies onlyy engineered-safety-feature atmosphere cleanup systems designed to mitigate the consequences of postulated accidents.


required to respond to, the information collection.
It addresses the atmosphere cleanup system, including the various components and ductwork, in the postulated DBA environment.


==B. DISCUSSION==
==B. DISCUSSION==
Atmosphere cleanup systems are included as ESFs in the design of light-water-coolednuclear power plants to mitigate the radiological consequences of postulated accidents.  The mitigating action of ESF atmosphere cleanup systems is limited to the removal of radioactive iodine (both elemental iodine and organic iodides) and particulate matter (aerosols) that may be released into the building or containment during and after the accident; the removal of fission product noble gases by ESF atmosphere cleanup systems is negligible. ESF atmosphere cleanup
Atmosphere cleanup systems are included as en-gineered safety features in the design of liglil.witer.
1.52-3systems should be designed to operate under the environmental conditions that would be generatedduring and after design basis accidents.In this guide, ESF atmosphere cleanup systems that must operate under postulated DBAconditions inside the primary containment are designated as "primary systems."  ESF systems required to operate outside the primary containment under postulated DBA conditions that are generally less severe are designated as "secondary systems."  Secondary systems include such systems as the standby gas treatment system (SGTS) and the atmosphere cleanup systems for the spent fuel handling building, control room, shield or annulus building, secondary containment, as well as emergency core cooling system (ECCS) pump leakage.  Figures 1 and 2 depict sample ESF
atmosphere cleanup systems.For most currently licensed plants, the characteristics of the fission product release fromthe core into the containment were set forth in Regulatory Guides 1.3 (Ref. 1) and 1.4 (Ref. 2) and were derived from Technical Information Document (TID) 14844, "Calculation of Distance Factors for Power and Test Reactor Sites" (Ref. 3).  This source term has been used in the design basis applications for light-water-cooled nuclear power plants.  Since the publication of TID-
14844 in 1962, significant advances have been made in understanding the timing, magnitude, and chemical form of fission product releases from severe nuclear power plant accidents.  In 1995, the


NRC published NUREG-1465 (Ref. 4), which provides estimates of an alternative accident source term based on insights from severe accident research. The NRC enacted 10 CFR 50.67 to provide a means for operating reactors to change their design basis source terms.  Regulatory Guide 1.183 (Ref. 5) was developed to provide guidance to licensees of operating power reactors on acceptable applications of alternative source terms.  Regulatory Guide 1.183 establishes an acceptable alternative source term (AST) and identifies the significant attributes of other ASTs that may be found acceptable by the NRC staff.  Regulatory Guide 1.183 also identifies acceptable radiological analysis assumptions for use in conjunction with the accepted AST. The NRC staff expects that future plants will use the alternative accident source term in support of safety analyses performed
cooled nuclear power plants to mitigate the c0rs,..quences of postulated accldwnts by removing fr',rn the building or conltailliment atmosphere radioactive mnateral that may be rtdeased in the accident.


in accordance with 10 CFR 50.34 and 10 CFR 50.90.The DBA environmental design conditions for a given ESF system (primary and secondarysystems) should be determined for each plant. DBA radiological design conditions for typical primary and secondary systems should be based on the radiation source term specified in Regulatory Guides 1.3 (Ref. 1), 1.4 (Ref. 2), 1.25 (Ref. 6), or 1.183 (Ref. 5), as applicabl
All such cleanup systems should be dsiped it) operate uider the environnmental conditions resulting from die accideit.in this guide, atmosphere cleanup systems that nitist operate under postulated DBA conditions inside the primary containment (i.e., recirculating systems) are designated as primary systems. Systems required to operate under conditions that are generally less severe (Le., recirculating or once-through systems) are desig-nated as secondary systems. Secondary systems typically include the standby gas treatment system and the emergency air cleaning systems for the fuel handliiig building, control room, and shield building.The DBA environmental conditions for a Liven system should be determined for each plant. DBA environmental conditions for typical primary and secondary systems are shown in Table I. In addition.primary systems should be designed to withstand tie radiation dose from water and plateout sources in the containment and the corrosive effects of chemical sprays (if such sprays are included in the plant design).An atmosphere cleanup system consists of sonic or all of the following components:
demisters, heaters. pre-filters, high-efficiency particulate air (HEPA) filters, adsorption units, fans, and associated ductwork, valv.ing, and instrumentation.


====e.  DBA====
The purpose of the decnister is to remove entrained water droplets from die inlet USNRC AEGULATORY
environmental design conditions such as temperature, relative humidity, and pressure should also be considered.  In addition, primary systems should be designed to withstand the radiation dose from water and plateout sources in the containment and the corrosive effects of chemical sprays (if such sprays are included in the plant design).  An ESF atmosphere cleanup system consists of housing, dampers, fans, and associatedductwork, motors, valves, and instrumentation.  Typical components within the housing are moisture separators, heaters, prefilters, high-efficiency particulate air (HEPA) filters, medium- efficiency postfilters, and iodine adsorption units.
GUIDES Comments ftould be sent to the Secetatev of the Commit$'*r U 6 Nuclse, Reegulatorl Commission.


1.52-4The housing is the portion of an ESF atmosphere cleanup system that encloses air cleaningcomponents and provides connections to adjacent ductwork.  Each of these components may be used for moving, cleaning, heating, cooling, humidifying, or dehumidifying the air stream.The principal purpose of dampers in an ESF atmosphere cleanup system is to shut off orseal the system components from air flowing in a designated flow path.  A typical unit has dampers both upstream and downstream from the "train" of components, i.e., upstream from the moisture separator and downstream from the last HEPA filter or iodine adsorber.  The dampers prevent or isolate unwanted flow or circulation of the normal air stream through the system components in order to preserve or extend the useful service life of the filtration and iodine adsorption media.  ESF system dampers may also serve secondary functions such as flow control, pressure control, balancing, pressure relief, or backflow prevention.  This guide does not address the fire prevention aspect of dampers in ESF atmosphere cleanup systems.
Wathington.


The principal purpose of a moisture separator is to remove entrained water droplets  fromthe inlet air stream, thereby protecting HEPA filters and iodine adsorbers from water damage and plugging.  Moisture separators may also function as prefilters in some system designs.Heaters normally follow the moisture separators in the cleanup train.  They are designed toheat the incoming air stream to reduce the stream's relative humidity upstream from the HEPA
0 C 2OU. Attention Doielblim and~Regulatory Guides ate ilsued to describe and make available to the public Service Sectiomt methods eoeet6able to thl NRC ,e:If of implementing specific perts of ihe Commission'e seouleione.
filters and iodine adsorbers during system operation to minimize adsorption of water vapor from the air by the iodine adsorbers. As an added measure, some designs use heaters (or some other


mechanism) to prevent condensation within the isolated components of the cleanup unit while the
0 adlhnete'
techniques used by the $tlef in vei1u the guides spa Issued in the following ton broad divisions cling specific problems or pOS1ulated accidents, or to piovidte guidance to eppli cen.t Regulatory Guides or* not substitute$ iegulalitlln and complience I Power Reactors 6 Products with them is not (iquired Melthods and solutions dilt cent from those eel ou0 in 2 Research and Telt leactore 1 Transportation the guides w)iI be acceptable it they provide a basis tlo the findings requisite to 3 Fuels end Metesiels Facilities
8 Occupational Htelth the issuance at continuance of a permit or license by the Commission
4 Environmental Silti 2 Antitrust  Comments and sugg6esti01l for improvement;
in those guide% ate encouraged
5 Materials enid Pllnt Protection
10 General at ell limes, and guides :ill be revised me epptoprlete to accomrnodate cam ments and Io reflect new information ao edaperince Howovee. comments on Copies Of pubtlthed guides mar be obteined by writen request indicating tire this it #rCeived wilhin about two months aftr 4lte istsuince will be per divisione desired to the U S Nuclear Regulatory Comnseteion Washington DC hiculeil usslUl in evaluating thi neimed to-n e.lrly rvii.On 20%5 Atlentuon Direcio, 011,c of Siendedl enstlopmlntit stream. thereby protecting pretilters, HEPA filters, and adsorbers front water damage awd plugging.


cleanup units are not in service.Prefilters and HEPA filters are installed to remove particulate matter from the air stream. Prefilters remove the larger airborne particles from the air stream and prevent excessive loading of the HEPA filters. The HEPA filters remove the fine discrete particulate matter from the air stream.  A HEPA filter or a medium efficiency postfilter (as defined in Section 5.3 of ASME
Heaters.when used on secondary systems, normally follow the demisters in the cleanup train and are designed to mix and heat the incoming stream to reduce the stream's relative humidity before it reaches the filters and adsorbers.


N509-1989 (Ref. 7)) downstream from the adsorption units collects carbon fines and provides additional protection against particulate matter release in case of failure of the upstream HEPA
Prefihters and HEPA filters are installed to remove particulate matter, which may be radioactive.
filter bank.  It is not necessary to perform in-place leak testing on postfilters or HEPA filters downstream from the carbon adsorbers.  It is advantageous for the postfilters or HEPA filters downstream from the carbon adsorbers to be installed in separate housings or to be removed from the housing (for systems with a fan downstream from the housing) during in-place leak testing of the upstream HEPA filter.  This will contribute to the accuracy of the test results for the upstream HEPA filter.  The arrangement of the ductwork and the transitions between the separate housings can provide a torturous path that will aid in mixing the challenge agent.  Removing the filters downstream from the carbon adsorbers will permit sampling downstream from the fan.  The fan will provide the necessary mixing for an accurate test and the absences of the postfilters or HEPA
filters downstream from the carbon adsorbers will prevent the challenge aerosol from being removed from the air stream.


1.52-5The iodine adsorption units typically consist of impregnated activated carbon and areinstalled to remove gaseous radioactive elemental and organic forms of iodine from the air stream during design basis accidents.The location of the fan, with respect to the overall system design and the individual ESFatmosphere cleanup unit, is important because of the imposed positive and negative pressure gradients the fan creates during operation.  Consideration should be given to the impact of the ESF
Prefilters remove the larger particles and prevent excessive loading of HEPA filters; to some extent dernisters may a!so perform this function.
atmosphere cleanup unit's operating pressure with respect to surrounding areas in the system design.  For example, when the ESF atmosphere cleanup system is located in a radioactively contaminated area and the air is supplied to a given radioactively clean area or exhausted to the environment, it is advantageous to locate the fan upstream from the ESF atmosphere cleanup unit.


This minimizes the potential for unfiltered in-leakage into the radioactively clean area or inadvertent release of radioactive materials to the environment.  When the ESF atmosphere cleanup system is located in a radioactively clean area, it is advantageous to locate the fan downstream from the ESF atmosphere cleanup unit.  This minimizes the potential for outward leakage of radioactive materials into the radioactively clean area.The environmental operating conditions preceding a postulated DBA may affect theperformance of ESF atmosphere cleanup systems during and following a DBA.  Industrial contaminants, pollutants, high temperature, and high relative humidity contribute to the aging and weathering of filters and adsorbers and may reduce their effective capability to perform their intended design functions.  Therefore, aging and weathering, both of which will vary according to site-specific conditions, should be considered during design, operation, and maintenance.  The potential for condensation of moisture inside ESF atmosphere cleanup systems when in a shutdown or standby mode of operation should also be given design consideration, e.g., provision for space heaters.  The effects of these environmental factors on the performance of the ESF
The HEPA filters remove the fine discrete particulate matter and pass the air stream to the adsorber.
atmosphere cleanup system should be determined by scheduled periodic inspection and testing during operation.All components of ESF atmosphere cleanup systems should be designed for reliableperformance under accident conditions.  Initial testing, periodic inspection and testing, and proper maintenance are primary factors in ensuring the reliability of the ESF atmosphere cleanup system.


Careful attention to problems of ESF system maintenance during the design phase can contribute significantly to the reliability of the system by increasing the ease of such maintenance. A layout that provides accessibility and sufficient working space to safely and efficiently perform the required maintenance functions is of particular importance in the design. Periodic inspection and testing during operation of the components is another important means of ensuring reliability. It is important to perform periodic inspections and tests of the ESF atmosphere cleanup system in a manner that is consistent with the way the system was intended to operate during an accident.
The adsorber removes gaseous iodine (ele.mental iodine and organic iodides) from the air stream.IIEPA filters downstream Df the adsorption units collect carbon fines. The fan is the final item in an atmosphere cleanup train.The environmental conditions preceding a postulated DIA may affect the performance of the atmosphere cleanup system. Such factors, for example, as industrial contaminants, pollutants, temperature, and relative humidity contribute to the aging and weathering of filters and adsorbers and reduce their capability to perform their intended functions.


Built-in features that will facilitate convenient access for in-place testing are important in ESF
Therefore, aging and weathering of the filter: and adsorbers, both of which vary from site to site, should be considered during design and operation.
system design.Standards acceptable to the NRC staff for the design and testing of ESF atmospherecleanup systems include those portions of ASME N509-1989, "Nuclear Power Plant Air-Cleaning Units and Components" (Ref. 7); ASME N510-1989, "Testing of Nuclear Air-Treatment Systems"
1.52-6(Ref. 8); and ASME AG-1-1997, "Code on Nuclear Air and Gas Treatment" (Ref. 9) that arereferenced in this guide, and ASTM D3803-1989, "Standard Test Methods for Nuclear-Grade Activated Carbon" (Ref. 10).If a referenced standard has been incorporated separately into the NRC's regulations,licensees and applicants must comply with that standard as set forth in the regulation.  If the referenced standard has been endorsed in a regulatory guide, the standard constitutes a method acceptable to the NRC staff for meeting a regulatory requirement as described in the regulatory guide.  If a referenced standard has been neither incorporated into the NRC's regulations nor endorsed in a regulatory guide, licensees and applicants may consider and use the information in the referenced standard if appropriately justified, consistent with current regulatory practice.


==C. REGULATORY POSITION==
Average temperature and relative humidity also vary from site to site, and the potential buildup of moisture in the adsorber should also be given design consideration.
1. GENERAL DESIGN AND TESTING CRITERIA
ASME AG-1-1997, "Code on Nuclear Air and Gas Treatment" (Ref. 9), and ASME N509-1989, "Nuclear Power Plant Air-Cleaning Units and Components" (Ref. 7), provide criteria that are acceptable to the NRC staff for the performance, design, construction, acceptance testing, and quality assurance of equipment used as components in nuclear safety-related or engineered safety featured air and gas treatment systems in nuclear power plants.  ESF atmosphere cleanup systems designed to ASME N509-1989 (or its earlier versions) and tested to ASME N510-1989 (or its earlier versions) (Ref. 8) are considered adequate to protect public health and safety. 2. ENVIRONMENTAL DESIGN CRITERIAAll parts and components of the ESF atmosphere cleanup system should be selected anddesigned to operate under the environmental conditions specified by the following guidelines.


2.1.  In accordance with Section 4.4 of ASME N509-1989 (Ref. 7), the design of an ESFatmosphere cleanup system should be based on the anticipated range of operating parameters of temperature, pressure, relative humidity, radiation levels, and airborne iodine concentrations that are likely during and following the postulated DBA.
The effects of these environmental factors on the atmosphere cleanup systemn should be determined by scheduled testing during operation.


2.2.The location and layout of each ESF atmosphere cleanup system should considerthe radiation dose to essential services and personnel in the vicinity, integrated over the 30-day period following the postulated DBA.  The radiation source term should be consistent with the assumptions found in Regulatory Guides 1.3 (Ref. 1), 1.4 (Ref. 2), 1.25 (Ref. 6), or 1.183 (Ref. 5).
All components, of atmosphere cleanup systems should be designed for reliable performance under accident conditions.
Other ESFs, including pertinent components of essential services such as power, air, and control cables, should be adequately shielded from the ESF atmosphere cleanup systems.


2.3.The design of each adsorber should be based on the concentration and relativeabundance of the iodine species (elemental, particulate, and organic) and should be consistent with
Initial testing and proper mainte.nance are primary factors in ensuring the reliability of the system. Careful attention during the design phase to problems of system maintenance can contribute signifi-cantly to the reliability of the system by increasing the ease of such maintenance.
1 Surge protection devices such as pressure relief valves that have the potential to be an effluent discharge path should bemonitored in accordance with General Design Criterion 64 of Appendix A to 10 CFR Part 50.


1.52-7the assumptions found in Regulatory Guides 1.3 (Ref. 1), 1.4 (Ref. 2), 1.25 (Ref. 6), or 1.183 (Ref. 5).
Of particular importance in the design is a layout that provides accessibility and sufficient working space so that the required functions can be performed safely. Periodic testing during opera.Lion to verify the efficiency of the components is another important means of ensuring reliability.
2.4.The operation of any ESF atmosphere cleanup system should not degrade theoperation of other ESFs such as containment spray systems, nor, conversely, should the operation of other ESFs such as containment spray systems, nor, conversely, should the operation of ESFs such as containment spray systems degrade the operation of any ESF atmosphere cleanup system.


2.5.Components of systems connected to compartments that are unheated during apostulated accident should be designed for the post-accident effects of both the lowest and highest predicted temperatures.
Built-in features that will facilitate convenient in-place testing are important in system design.Standards for the design and testing of atmosphere cleanup systems include draft standard ANSI N509,'Lines indicate substantyv- changes from previously published regulatory guide."Nuclear Power Plant Air Cleaning Units and Comnpo.rients" (Ref. 1), and ANSI N510.1975, "Testing of Nuclear Air Cleaning Systems" (Ref. 2).Other standards are available for the construction and testing of certain components of systems. Where such standards are acceptable to the NRC staff, they are referenced in this guide. Where no suitable standard exists, acceptable approaches are presented in this guide.ORNL.NSIC-65, "Design, Construction and Testing of High-Efficiency Air Filtration Systems for Nuclear Ap-plication" (Ref. 3), provides a comprehensive review of air filtration systems. It is not a standard but a guide that discusses a number of acceptable design alternatives.


2.6.The design of an ESF atmosphere cleanup system should consider any significantcontaminants that may occur during a DBA such as dusts, chemicals, excessive moisture, or other particulate matter that could degrade the cleanup system's operation.3.SYSTEM DESIGN CRITERIAESF atmosphere cleanup systems should be designed in accordance with Section 4 ofASME N509-1989 (Ref. 7) as modified and supplemented by the following.
C. REGULATORY
POSITION 1. Environmental Design Criteria a. The design of an engineered-safety.feature at.mosphere cleanup system should be based on the maximum pressure differential, radiation dose rate, relative humidity, maximum and minimum temperature, and other conditions resulting from the postulated DBA and on the duration of such conditions.


3.1.ESF atmosphere cleanup systems designed and installed for the purposeof mitigating accident doses should have redundant units (trains) to provide assurance that  an operable unit will be available during the DBA. A typical unit is composed of the following components:  (1) moisture separator, (2) prefilter (a moisture separator may serve this function), (3)
b. The design of each system should be based on the radiation dose to essential services ih the vicinity of the adsorber section integrated over the 30.day period following the postulated DBA. The radiation source term should be consistent with the assumptions found in Regulatory Guides 1.3 (Ref. 4), 1.4 (Ref. 5), and 1.25 (Ref. 6). Other engineered safety features, incluing pertinent components of essential services such as power, air, and control cables, should be adequately shielded from the atmosphere cleanup systems.c. The design of each adsorber should be based on the concentration and relative abundance of the iodine species (elemental, particulate, and organic), which should be consistent with the assumptions found in Regulatory Guides 1.3 (Ref. 4), 1.4 (Ref. 5), and 1.25 (Ref. 6).d. The operation of any atmosphere cleanup system should not deleteriously affect the operation of other engineered safety features such as a containment spray system, nor should the operation of other en-gineered safety features such as a containment spray system deleteriously affect the operation of any atmos-phere cleanup system.e. Components of systems connected to compart.ments that are unheated during a postulated accident should be designed for postaccident effects of both the lowest and highest outdoor temperatures used in the plant design.*1 1.52-2
heater, (4) HEPA filter before the adsorbers, (5) iodine adsorber (impregnated activated carbon), (6)  
2. System Design Criteria a. Atmosphere cleanup systems designed and in.stalled for the purpose of mitigating accident doses should be redundant.
HEPA filter or medium efficiency postfilter (as defined in Section 5.3 of ASME N509-1989) after


the adsorbers, (7) fan, and (8) interspersed ducts, motors, dampers, valves, and related
The systems should consist of the following weqt..ntial components:
(1) demisters, (2)prefilters (Gemisters may serve this function), (3) HEPA filters before the adsorbers, (4) iodine adsorbers (impreg.nated activated carbon or equivalent ads.,rbent such as metal zeolites), (5) HIEPA filters after the adsorbers, (6)ducts and valves, (7) fans, and (8) related instrumenta.


instrumentation.
tion. Heaters or cooling coils should be used when the humidity is to be controlled before filtration.


3.2.The redundant ESF atmosphere cleanup units should be physically separated so thatdamage to one unit does not also cause damage to the other unit. The generation of missiles from high-pressure equipment rupture, rotating machinery failure, or natural phenomena should be considered in the design for separation and protection.
b. The redundant atmosphere cleanup systems should be physically separated so that damage to one system does not also cause damage to the second system.The generation of missiles from high-pressure equipment rupture, rotating machinery failure, or natural pheno-mena should be considered in the design for separation and protection.


3.3. If the ESF atmosphere cleanup system is subject to pressure surges resulting from thepostulated accident, the system should be protected from such surges. Each component should be
c. All components of an engineered-safety-feature atmosphere cleanup system should be designated as Seismic Category I (see Regulatory Guide 1.29 (Ref. 7))if failure of a component would lead to the release of significant quantities of Fission products to the working or outdoor environments.


protected with devices such as pressure relief valves
d. If the atmosphere cleanup system is subject to pressure surges resulting from thie postulated accident, the system should be protected from such'surges.
1 so that the overall system will perform itsintended function during and after the passage of the pressure surge.


3.4. All components of an ESF atmosphere cleanup system whose failure would lead tothe release of fission products that would exceed the regulatory limits should be designated as Seismic Category I (Regulatory Guide 1.29 (Ref. 11)).
Each component should be protected with such devices as pressure relief valves so that the overall system will perform its intended function during and after the passage of the pressure surge.e. In the mechanical design of the sy: tem, the high radiation levels that may be associated with buildup of radicactive materials on the system components should be given particular consideration.
1.52-8 3.5. In the mechanical design of the ESF system, the high radiation levels that may beassociated with buildup of radioactive materials on the ESF system components should be given particular consideration. ESF system construction materials should effectively maintain their


intended function under the postulated radiation levels. The effects of radiation should be considered not only for moisture separators, heaters, HEPA filters, adsorbers, motors, and fans, but also for any electrical insulation, controls, joining compounds, dampers, gaskets, and other organic materials that are necessary for operation during and after a postulated DBA. In addition to the consideration of high radiation levels, the mechanical design of the ESF system should be based on consideration of other harsh conditions that may occur during a DBA such as high humidity, containment rain-out, chemical sprays, or high temperatures and pressures.
System con-struction
*materials should effectively perform their intended function under the postulated radiation levels.The effects of radiation should be considered not only for the demisters, heaters. HEPA fidters, adsorbers, and fans, but also for any electrical insulation, controls, joining compounds, dampers, gaskets, and other organic-containing materials that are necessary for opera-tion during a postulated DBA.f. The volumetric air flow rate of a single cleanup train should be limited to approximately
30,000 cfm. If a total system air flow in excess of this rate is required, multiple trains should be used. For ease of maintenance, a filter layout three HEPA filters high and ten wide is preferred.


3.6.To ensure reliable in-place testing, the volumetric air-flow rate of each cleanup unitshould be limited to approximately 30,000 cubic feet per minute. If a total system air flow in excess of this rate is required, multiple units should be used. For ease of maintenance, a filter layout three HEPA filters high and ten wide is preferred. Each ESF atmosphere cleanup system train should be designed such that at the maximum accident flow rate the adsorber residence time is not less than the design value (typically 0.25 seconds per 2 inches of activated carbon) as specified in Regulatory Position 4.11 of this guide. The residence time should be calculated in accordance with Article I-1000 of Sections FD and FE of ASME AG-1-1997 (Ref. 9). 
g. The atmosphere cleanup system shovld be instrumented to signal. alarm, and record pertinent pressure drops and flow rates at the control room.hi. The power supply and electrical distribution system for the atmosphere cleanup system described in Section C,2.a above should be designed in accordance with Regulatory Guide 1.32 (Ref. 8). All instrumenta- tion and equipment controls should be designed to IEEE Standard 279 (Ref. 9). The system should be qualified and tested under Regulatory Guide 1.89 (Ref. 10). To the extent applicable, Regulatory Guide 1.30 (Ref. I I)and IEEE Standards
3.7.The ESF atmosphere cleanup system should be instrumented to signal, alarm, andrecord pertinent pressure drops and flow rates at the control room in accordance with
334 (Ref. 12), 338 (Ref. 13), and 344 (Ref. 14) should be considered in the design.i. To maintain radiation exposures to operating personnel as low as is reasonably achievable during plant maintenance, atmosphere cleanup systems should be designed to facilitate maintenance in accordance with the guidelines of Regulatory Guide 8.8 (Ref. 15). The cleanup train should be totally enclosed.Each train should be designed and installed in a manner that permits replacennent of the train as an intact unit or as a minimum number of segmented sections without removal of individual components.


recommendations of Section 5.6 of ERDA 76-21 (Ref. 12) and Section 4.9 of ASME N509-1989 (Ref. 7).3.8.The power supply and electrical distribution system for the ESF atmosphere cleanupsystem should be designed in accordance with Regulatory Guide 1.32 (Ref. 13). All instrumentation and equipment controls should be designed to IEEE Standard 603-1991 (Ref. 14).  
j. Outdoor air intake openings should be equipped with louvers, grills, screens, or similar protective devices to minimnize the effects of high winds, rain, snow, ice, trash, and other contaminants on the operation of the system. If the atmosphere surrounding the plant could contain significant environmental contaminants, such as dusts and residues from smoke cleanup systems from adjacent coal burning power plants or industry, the design of the system should consider these contaminants and prevent them from affecting the operation of any atmosphere cleanup system.k. Atmtosphere cleanup system housings and duct-work should be designed to exhibit on test a maximum total leakage rate as defined in Section 4.12 of draft standard ANSI N509 (Ref. 1). Duct and housing leak tests should be performed In accordance with the recommendations of Section 6 of ANSI N510-1975 (Ref. 2).3. Component Design Criteria and Qualification Test-ing a. The demisters installed in engineered-safety- feature atmosphere cleanup systems should meet qualifi-cation requirements similar to those found in MSAR 71.45, "Entrained Moisture Separators for Fine Particle Water-Air-Steam Service, Their Performance, Develop-ment and Status" (Ref. 16). Demisters should meet Underwriters'
The ESF system should be qualified and tested under Regulatory Guide 1.89 (Ref. 15).  To the extent applicable, Regulatory Guides 1.30 (Ref. 16), 1.100 (Ref. 17), and 1.118 (Ref. 18) and IEEE
Laboratories (UL) Class I (Ref. 17)requirements.
Standard 334 (Ref. 19) should be considered in the design.


3.9.Unless the applicable ESF atmosphere cleanup system operates continuously duringall times that a DBA can be postulated to occur, the system should be automatically activated upon the occurrence of a DBA by (1) a redundant ESF actuation signal (e.g., temperature, pressure) or (2)
1.52-3 b. Adsorption units function efficiently at a rela-tive humidity of 70%. If heaters are used on s&#xfd;condary systems, the heating section should reduce the relative humidity of the !ncoming atmosphere from 100% to 70% during postulated DBA conditions.
a signal from redundant Seismic Category I radiation monitors.


3.10.To maintain radiation exposures to operating and maintenance personnel as low as isreasonably achievable (ALARA), ESF atmosphere cleanup systems and components should be designed to control leakage and facilitate maintenance, inspection, and testing in accordance with the guidance of Regulatory Guide 8.8 (Ref. 20).  The ESF atmosphere cleanup unit should be totally enclosed. To minimize the potential contamination of the area when maintaining the ESF
A prototype heating element should be qualified under postulatet DBA conditions.
atmosphere cleanup system, the system should be designed and installed in a manner that permits replacement of an entire unit or a minimum number of segmented sections without removal of


individual components.
Consideration should be given in system design to mirnumizing heater control malfunction.


2 The pertinent quality assurance requirements of Appendix B, "Quality Assurance Criteria for Nuclear Power Plants and FuelReprocessing Plants," to 10 CFR Part 50 apply to all activities affecting the safety-related functions of all components of the ESFatmosphere cleanup system.
The heater stiould not be a potential ignition adsorbent source.c. Materials used in the prefilters should withstand the radiation levels and environmental conditions preva-lent during the postulated DBA. Prefilters should meet UL Class I (Ref. 17) requirements and should be listed in the current UL Building Materials List (Ref. 18). The prefilters should have not less than a 40% atmospheric dust spot efficiency rating (see Section 9 of the ASHRAE Standard 52, "Method of Testing Air Cleaning Devices Used in General Ventilation for Removing Particulate Matter" (Ref. 19)).d. The HEPA filters should be steel cased and designed to military specifications MIJ,-F-51068D (Ref.20) and MIL-F-51079B (Ref. 21). The HEPA filters should satisfy the requirements of UL-586 (Ref. 22).The HEPA filter separators should be capable of withstanding iodine removal sprays if the atmosphere cleanup system will be exposed to such sprays following a DBA. HEPA filters should be tested individually by the appropriate Filter Test Facility listed in the current Energy Research and Development Administration (formerly USAEC) Health and Safety Bulletin for the Filter Unit Inspection and Testing Service (Ref. 23). The Filter Test Facility should test each filter for penetration of dioctyl phthalate (DOP) in accordance with the recommendations of MIL-F-5 1068D (Ref. 20) and MIL-STD-282 (Ref. 24).e. Filter and adsorber mounting frames should be constructed and designed in accordance with the recom-mendations of Section 4.3 of ORNL-NSIC-65 (Ref. 3).f. Filter and adsorber banks should be arranged in accordance with the recommendations of Section 4.4 of ORNL.NSIC-65 (Ref. 3).g. System filter housings, including floors and doors, should be constructed and designed in accor-dance with the recommendations of Sections 4.5.2, 4.5.5, 4.5.7, and 4.5.9 of ORNL-NSIC-65 (Ref. 3).h. Water drains should be designed in accordance with the recommendations of Section 4.5.6 of ORNL-NSIC-65 (Ref. 3).i. The adsorber section of the atmosphere cleanup system may contain any adsorbent material demon-strated to remove gaseous iodine (elemental iodine and organic iodides) from air at the required efficiency.


1.52-9 3.11.Outdoor air intake openings should be equipped with louvers, grills, screens, orsimilar protective devices to minimize the effects of high winds, rain, snow, ice, trash, and other contaminants on the operation of the system.  The outdoor air intake openings should be located to minimize the effects of possible onsite plant contaminants, such as the diesel generator exhaust. If the atmosphere surrounding the plant could contain significant environmental contaminants, such as dusts and residues from smoke cleanup systems from adjacent coal-burning power plants or industry, or is a salty environment near an ocean, the design of the system should consider these contaminants and prevent them from affecting the operation of any ESF atmosphere cleanup system. 3.12. ESF atmosphere cleanup system housings and ductwork should be designed toexhibit on test a maximum total leakage rate as defined in Section SA-4500 of ASME AG-1-1997 (Ref. 9). Duct and housing leak tests should be performed in accordance with Section TA of ASME
Since impregnated activated carbon is commonly used, only this adsorbent is discussed in this guide. Each original or replacement batch of impregnated activated carbon used in the adsorber section should meet the qualification and batch test results summarized in Table 2 of this guide. If an adsorbent other than impregnated activated carbon is proposed or if the mesh size distribution is different from the specifications in Table 2, the proposed adsorbent should have demonstrated the capability to perform as well as or better than activated carbon in satisfying the specifications in Table 2.If impregnated activated carbon is used as the adsorbent, the adsorber system should be designed for an average atmosphere residence time of 0.25 sec per two inches of adsorbent bed. The adsorber should have the capacity of loading 2.5 ing of total iodine (radio-active plus stable) per gram of activated carbon. No more than 5% of impregnant
(50 mg of impregnant per gram of carbon) should be used. The radiation stability of the type of carbon specified should be demonstrated and certified (see Section C.L.b of this guide for the design source term).j. If tray or pleated-bed adsorbent canisters are used in the adsorbent section. they should be designed in accordance with the recommendations of CS.8T,"Tentative Standard for High-Efficiency Gas-Phase Ad-sorber Cells" (Ref. 25). The activated carbon should be totally restrained in the adsorber.


AG-1-1997.4.COMPONENT DESIGN CRITERIA AND QUALIFICATION TESTINGComponents of ESF atmosphere cleanup systems should be designed, constructed, andtested in accordance with Division II of ASME AG-1-1997 (Ref. 9), as modified and supplemented by the following.
A qualification test on a prototype adsorber should be performed in accordance with paragraph
7.4.1 of CS-8T (Ref. 25), except that the safe shutdown earthquake parameters particular to the site should be used. The adsorber should be tested both before and after the qualification test and should show no significant increased penetration when challenged with a gaseous halogenated hydrocarbon refrigerant in accordance with USAEC Report DP-1082 (Ref. 26).To ensure that the adsorber section will contain carbon of uniform packing density, written procedures for filling the adsorber beds should be prepared and followed in accordance with the recommendations of Section 7.4.2 of CS-8T (Ref. 25).k. The design of the adsorber section should consider possible iodine desorption and adsorbent auto-ignition that may result from radioactivity-induced heat in the adsorbent and concomitant temperature rise.Acceptable designs include a low-flow air bleed system, cooling coils, water sprays for the adsorber section, or other cooling mechanisms.


2 4.1.Moisture separators should be designed, constructed, and tested in accordance withSection FA of ASME AG-1-1997.
Any cooling mechanism should satisfy the single-failure criterion.


4.2.Air heaters should be designed, constructed, and tested in accordance with Section CA of ASME AG-1-1997.
A low-flow air bleed system should satisfy the single-failure criterion for providing low-humidity (less than 70% relative humidity)
cooling air flow.I. The system fan, its mounting, and the ductwork ,connections should be designed and constructed in 1.52-4 accordance with tile recomtmendatioiss ti Section 2.7 kt ORNL.NSIC.65 (Ref. 3).m. The fan or blower used on the cleanup system should be capable of operating under the environlmental conditions postulated, including radiation.


4.3.Materials used in the prefilters should withstand the radiation levels andenvironmental conditions prevalent during the postulated DBA. Prefilters should be designed, constructed, and tested in accordance with Section FB of ASME AG-1-1997.
n. Duclwork should be designed in accordance with the recommnendations of Section 2.8 (if ORNL.NSIC.65 (Ref. 3).o. Ducts and housings should be laid out with a minimun of ledges, protrusions, and crevices thac could collect dust and moisture and that could impede personnel or cicate a hazard to then in the performance of their work. Straightening valnes should be installed to ensure representative air flow trmeasurement and uniform flow distribution through cleanup components.


4.4.HEPA filters used in ESF atmosphere cleanup systems should be designed,constructed, and tested in accordance with Section FC of ASME AG-1-1997. HEPA filters should be compatible with the chemical composition and physical conditions of the air stream.Each HEPA filter should be tested by the manufacturer (or by a qualified filter test facility)for penetration of a challenge aerosol such as dioctyl phthalate (DOP) in accordance with the procedures of Section TA of ASME AG-1-1997. Testing and documentation should be in accordance with a quality assurance program consistent with Appendix B to 10 CFR Part 50.
4. Maintenance a. To keep radiation exposures to operating personnel as low as is reasonably achievable, the atnlus-phere cleanup system should be designed to control leakage and permit maintenance in accUrdance with thie guidlines of Regtilatory Guide 8.8 ( Ref. I5).b. Accessibility of components and maintenance should be considered in the design of atmosphere cleanup systems in accordance with the recomninenda- tions of Sections 2.5.2. 2.5.3. and 2.5.4 of ORNL-NSIC-65 (Ref. 3).c. For ease of niaintena ice, tile system design should provide for a minimum of three linear feet from mounting frame to mounting frame between banks of components.


4.5.The HEPA filter and Type II adsorber cell mounting frames should be constructedand designed in accordance with Section FG of ASME AG-1-1997.
If components are to be replaced, the dimension to be provided should be the rnaxinun&#xb6;length of the component plus a minimum of three feet.d. The system design should provide for perma.nent test probes with external connections.


1.52-10 4.6.Filter and adsorber banks should be arranged in accordance with therecommendations of Section 4.4 of ERDA 76-21 (Ref. 12) and Section HA, "Housings," of ASME
Preferably, the test probes should be manifolded at a single convenient location, with due consideration given to balancing Qf line lengths and diameter to produce eliable test results for refrigerant gas, resistance, flow rate, and DOP testing.e. Each atmosphere cleanup train should be operated at least 10 hours per month, with tile heaters on (if so equipped), in order to reduce the buildup of moisture on the adsorbers and HEPA filters, f. The cleanup components (i.e., HEPA filters, prefiiters, and adsorbers)
should not be Installed while active construction is still in progress.5. I~li.l~ce "lesing (Critella a. 'lre .irllospliere cleanup system Should hi tested ii i place I I ) initially.


AG-1a-2000 (Ref. 21).
21 at least once jle tol)eIatiIIg cycle thereaftel tor svstelnis iirauntained ini a st.urmd'.k status or after 720 hoturs of' sh tem tiioelidtio'n, and (31 following paintilng, lire, or chemical release in anw ventilation zoine communicating with the systeml. A\visual i nspecti tit ' t the systeni and all associated components should he wlade before each test ill accol.dance with the recommendationis tot Section 5 of' ANSI N5 10-1975 (Ref. 2).b. The air flow distributiot:
4.7.System filter housings, including floors and doors, should be constructed anddesigned in accordance with Section HA of ASME AG-1a-2000 (Ref. 21).
to thie H-EPA fillets, and iodine adsorbers slihtild be tested in place inuutall\and at least once operating cycle thereafter t,11 unilOrmnity.
4.8.Water drains should be designed in accordance with the recommendations of Section4.5.8 of ERDA 76-21 (Ref. 12) and Section HA of ASME AG-1a-2000 (Ref. 21). Special design features, such as water traps for each drain, should be incorporated into drain systems to prevent contaminated air bypassing filters or adsorbers through the drain system.  Procedures should be in place to routinely verify the water level.


4.9.Adsorption units function most efficiently, with respect to retention of adsorbediodine, at an input relative humidity of 70% or less. If the relative humidity of the air entering the ESF atmosphere cleanup system is expected to exceed 70% during accident situations, humidity control should be provided in the system design for controlling the relative humidity of the air entering the system. Humidity control promotes the long-term retention of radioiodine in the iodine adsorbers(minimizing the potential for early desorption and release) by maintaining the relative humidity at less than or equal to 70%. For secondary systems, humidity control may be provided by either safety-related heaters or an analysis that demonstrates that the air entering the adsorbers is maintained at less than or equal to 70% relative humidity under all design basis accident conditions.
The distribution should be within +/-- 2` .,1 thie average olow per unit. The testing should 1ic conducted in accordance with the mecomnmerudations ,I Section 9 of "Industrial Ventilation'" (Ref. 2711 ind Section 8 of ANSI N5 10.1975 (Ref'. 2).k. The in-place DOI' test for IHEPA filters should conf'orm to Section 10 of ANSI N510..1975 (Ref. 2t I IEPA filter sections should be tested in place (It initially, (2) at least once per oIperatnig cycle tihcuCattel for systems maintained in a standby s:atus or at'let 7211 hours of svsteln operation, and (3) following paintio.fire, or chemical release in any ventilanton zone conlnlunicaling with tile systemu to Con1irill a petteti.tion of less than 0.051 at rated flow. An engineered- safety-feature air filtrationr system satist' ing this condi.tion can be considered to warrant a )99.7 remoual efficiency for particulates in accident dose evaluaroits.


For primary systems, an electric heater should not be provided because its use inside containment could result in a spark and possible hydrogen explosion in the event of an accident.  Systems with humidity control can perform laboratory testing of representative samples of activated carbon at a relative humidity of 70%, and systems without humidity control should perform laboratory testing of representative samples of activated carbon at a relative humidity of 95% (see Table 1 of this guide).4.10.Adsorbers should be designed, constructed, and tested in accordance withSection FD for Type II Adsorber cells or Section FE for Type III Adsorber cells of ASME AG-1-
IIEPA filters that fail to satisfy this condition should IV replaced with filters qualified pursuant to regulathc.


1997 (Ref. 9). The design of the adsorber section should consider possible iodine desorption and adsorbentauto-ignition that may result from radioactivity-induced heat in the adsorbent and concomitant temperature rise. Acceptable designs include a low-flow air bleed system, cooling coils, water sprays for the adsorber section, or other cooling mechanisms.  Any cooling mechanism should satisfy the single-failure criterion.  A low-flow air bleed system should satisfy the single-failure criterion for providing low humidity (less than 70% relative humidity) cooling airflow. When a water-based fire suppression or prevention (cooling) system is installed in the ESFatmosphere cleanup system housing, the fire system should be manually actuated unless there is a reasonable probability that the iodine desorption and adsorbent auto-ignition could occur in the housing, in which case the fire system should have both automatic and manual actuatio
position C.3.d of this guide. If the IHEPA filter bank ", entirely or only partially replaced.


====n. The fire ====
an in-place DO)' teit should be conducted.
3 Detection can be accomplished by a mechanical or electrical device, including but not limited to, thermal, carbon monoxide, orsmoke.4 Activated carbon is typically impregnated with a chemical compound or compounds to enhance radioiodine retention,particularly under high temperatures and humidity conditions.  Typical impregnants include iodides such as potassium iodide and triiodide, amines such as triethylenediamine (TEDA), and combinations thereof.


5 A "batch of activated carbon" or a "batch of impregnated activated carbon" is a quantity of adsorbent, not to exceed 10 cubicmeters (or 350 cubic feet) in size, of the same grade or type that has been produced under the same manufacturer's production designation using a consistent manufacturing procedure and equipment, and that has been homogenized to exhibit the same physical properties and performance characteristics throughout the mass.  (See Article FF-1130 of ASME AG-1-1997.)
If any welding repairs are necessary on. within. ,m adjacent to the ducts, htousing.
6A "lot of activated carbon" or a "lot of impregnated activated carbon" is that quantity of adsorbent consisting of one or morebatches of adsorbent that constitute and satisfy a purchase order. (See Article FF-1130 of ASME AG-1-1997.)
1.52-11system should use open spray nozzles or devices of sufficient size, number, and location to providecomplete coverage over the entire surface of the combustible filter media. The fire system should


be hard piped and supplied with a reliable source of water at adequate pressure and volume. The location of the manual release (or valve) for the fire system should be remote from the cleanup system housing and should be consistent with the ALARA guidance in Regulatory Guide 8.8 (Ref.
or mllournlting frailes. the filters and adsorbers should be removed fronm tile housing during such repairs. The repairs should be completed prior to periodic testing, filter inspection.


20). Automatic fire systems should include a reliable means of detection
arid in-place testing. Tire use of sili,:one sealants or an% othei temporary patching mnateial on filters. housing. nlloullt-ing frames, or ducts should not be allowed.d. The activated carbon adsorber section should be leak tested with a gaseous halogenated hrydrocarbon refrigerant in accordance with Section 12 of ANSI N510-1975 (Ref. 2) to ensure that bypass leakage through the adsorber section is less than 0.05%. During the test the upstream concentration of refrigerant gas should be no greater than 20 pprim. After the test is completed, air flow through tile unit should be main.1.52-5
3 to actuate the system. Cross-zoning of detectors is acceptable. Manual fire systems should include a reliable means of internal monitoring for determining when to manually actuate the fire systems.  The monitoring indication should be remote from the cleanup system housing in accordance with ALARA practices.
-. I tained until the residual refrigerant gas in the eltluent is less than 0.01 ppm. Adsorber leak testing should be conducted whenever DOP testing is done.b. Laboratory Testing Criteria for Activated Carbon a. The activated carbon adsorber section of the atmosphere cleanup system should be assigned the decontamination efficiencies given in Table 3 for ele.mental iodine and organic iodides if the following conditions are met: (1) The adsorber section meets the conditions given in regulatory position C.5.d of this guide, (2) New activated carbon meets the physical property specifications gi'.r in Table 2, and (3) Representative samples of used activated carbon pass the laboratory tests given in Table 3.If the activated carbon fails to meet any of the above conditions, it should not be used in engineered- safety-feature adsorbers.


4.11.The adsorber section of the ESF atmosphere cleanup system may contain anyadsorbent material demonstrated to remove gaseous iodine (elemental iodine and organic iodides)
b. The efficiency of the activated carbon adsorber section should be determined by laboratory testing of representative samples of the activated carbon exposed simultaneously to the same service conditions as the aasorber section. Each representative sample should be not less than two inches in both length and diameter, and each sample should have the same qualification and batch test characteristics as the system adsorbent.
from air at the required efficiency.  However, since impregnated activated carbon
4 is used almostexclusively, only impregnated activated carbon is discussed in this guide.  Each original or replacement batch or lot of impregnated activated carbon used in theadsorber section should meet Section FF-5000 of ASME AG-1-1997 (Ref. 9).
5, 6  A test performedas a "qualification test" should be interpreted to mean a test that establishes the suitability of a manufacturer's product for a generic application, normally a one-time test establishing typical performance of the product. Tests not specifically identified as being performed only for qualification purposes should be interpreted as "batch tests."  Batch tests are tests to be made on each production batch of product to establish suitability for a specific application.  Test conditions and acceptance criteria for batch tests should be the same as, or more stringent than, those specified in the plant's technical specifications for the specific application.  If impregnated activated carbon is used as the adsorbent, the adsorber system should bedesigned for an average atmosphere residence time of 0.25 seconds per 2 inches of adsorbent bed.


Sections FD and FE of ASME AG-1-1997 should be used to determine the residence time.  The adsorption unit should be designed for a maximum loading of 2.5 mg of total iodine (radioactive plus stable) per gram of activated carbon.  No more than 5% of impregnant (50 mg of impregnant per gram of carbon) should be used. The radiation stability of the type of carbon specified should be demonstrated and certified (see Regulatory Position 2.2 of this guide for the design source term). If an adsorbent other than impregnated activated carbon is proposed or if the mesh sizedistribution or other physical properties of the impregnated activated carbon are different from the
There should be a sufficient number of representative samples located in parallel with the adsorber section for estimat-ing the amount of penetration of the system adsorbent throughout its service life. The design of the samplers sh-ould be in accordance with the recommendations of i Appendix A of draft standard ANSI N509 (Ref. I.Where the system activated carbon is greater than two inches deep, each representative sampling station should consist of enough two-inch samples in series to equal the thickness of the system adsorbent.
1.52-12specifications above, the proposed adsorbent should have the capability to perform as well as orbetter than activated carbon that satisfies the specifications in Article FF of ASME AG-1-1997.If sample canisters are used, they should be designed in accordance with Appendix A of ASME N509-1989 (Ref. 7)
4.12.Ducts and filter housings should be laid out with a minimum of ledges, protrusions,and crevices that could collect dust and moisture and that could impede personnel or create a hazard to them in the performance of their work. Turning vanes or other air flow distribution devices


should be installed where needed to ensure representative air flow measurement and uniform flow distribution through cleanup components.
Once representative samples are removed for laboratory test, their positions in the sampling array should be blocked off.Laboratory tests of representative samples should be conducted, as indicated in Table 3 of this guide, with the test gas flow in the same direction as the flow during service conditions.


4.13.Dampers should be designed, constructed, and tested in accordance with Section DA
Similar laboratory tests should be performed on an adsorbent sample before loading into the adsorbers to establish an initial point for comparison of future test results. The activated carbon adsorber section should be replaced with new unused activated carbon meeting the physical property specifications of Table 2 after the last representative sample has been removed and tested or if any preceding representative sample has failed to pass the tests in Table 3.
of ASME AG-1-1997.


4.14.The system fan, its mounting, and the ductwork connections should be designed,constructed, and tested in accordance with Section BA for Blowers and Section SA for Ducts in ASME AG-1-1997 (Ref. 9). The fan or blower used on the ESF atmosphere cleanup system should be capable of operating under the environmental conditions postulated, including radiation.
===0. IMPLEMENTATION===
The purpose of thii section is to provide information to applicants and licensees regarding the NRC staff's plans for using this regulatory guide.This guide reflects current NRC staff practice.


Ductwork should be designed, constructed, and tested in accordance with Section SA of
There.fore, except in those cases in which the applicant or licensee proposes an acceptable alternative method, the staff will use the method described herein in evaluating an applicant's or licensee's capability for and perform-ance in complying with specified portions of the Commission's regulations until this guide is revised as a result of suggestions from the public or additional staff review.1.52-6 REFERENCES
I. Draft Standard ANSI N509 (Draft 9 -November 1975), "Nuclear Power Plant Air Cleaning Units and Components," American National Standards Institute.


ASME AG-1-1997.5.MAINTAINABILITY CRITERIAProvisions for maintaining ESF atmosphere cleanup systems should be incorporated in thesystem design in accordance with Section 4.8 of ASME N509-1989 (Ref. 7) and Section HA of ASME AG-1a-2000 (Ref. 21) as supplemented by the following:
2. ANSI N510-1975, "Testing of Nuclear Air Clean.ing Systems," American National Standards Institute.
5.1.Accessibility of components for maintenance should be considered in the design ofESF atmosphere cleanup systems in accordance with Section 2.3.8 of ERDA 76-21 (Ref. 12) and Section HA of ASME AG-1a-2000 (Ref. 21).  For ease of inspection and maintenance, the system design should provide for a minimum of 3 feet from mounting frame to mounting frame between banks of components. If components are to be replaced, the dimensions to be provided should be the maximum length of the component plus a minimum of 3 feet.


5.2.The cleanup components (i.e., HEPA filters, prefilters, and adsorbers) that are usedduring construction of the ventilation systems should be replaced before the system is declared
3. ORNL-NSIC-65, "Design, Construction, and Test-ing of High-Efficiency Air Filtration Systems for Nuclear Application," Oak Ridge National Laboratory, C.A.Burchsted and A.B. Fuller, January 1970.4. Regulatory Guide 1.3, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Boiling Water Reactors," Office of Standards Development, U.S. Nuclear Regula-tory Commission (USNRC).5. Regulatory Guide 1.4, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water Reactors," Office of Standards Development, USNRC.6. Regulatory Guide 1.25, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Fuel Handling Accident in the Fuel Handling and Storage Facility for Boiling and Pressurized Water Reactors," Office of Standards Development, USNRC.7. Regulatory Guide 1.29, "Seismic Design Classifica- tion," Office of Standards Development, USNRC.8. Regulatory Guide 1.32, "Criteria for Safety-Re- lated Electric Power Systems for Nuclear Power Plants," Office of Standards Development, USNRC.9. IEEE Std 279-1971, "Criteria for Protection Systems for Nuclear Power Generating Stations," Insti-tute of Electrical and Electronics Engineers.


operable.6.IN-PLACE TESTING CRITERIAInitial in-place acceptance testing of ESF atmosphere cleanup systems and componentsshould be performed in accordance with Section TA of ASME AG-1-1997 (Ref. 9).  Periodic,  
10. Regulatory Guide 1.89, "Qualification of Class IE Equipment for Nuclear Power Plants," Office of Standards Development, USNRC.11. Regulatory Guide 1.30, "Quality Assurance Requirements for the Installation, Inspection, and Test-ing of Instrumentation and Electric Equipment," Office of Standards Development, USNRC.12. IEEE Std 334-1974, "IEEE Standard for Type Tests of Continuous-Duty Class IE Motors for Nuclear Power Generating Stations," Institute of Electrical and Electronics Engineers.
7 In 1998, the Department of Energy (DOE) presented the results of its HEPA filter deterioration research at the 25th DOE/NRCNuclear Air Cleaning and Treatment Conference (Ref. 22). The results of this research demonstrated that wetting of the filter medium significantly reduces its tensile strength which is not fully recovered after drying.  In addition, further water exposu resresulted in additional losses in filter media tensile strength. (See NRC Information Notice 99-01, Reference 23.)
8 Painting, fire, or chemical release is "not communicating" with the HEPA filter or adsorber if the ESF atmosphere cleanupsystem is not in operation, the isolation dampers for the system are closed, and there is no pressure differential across the filterhousing.  This provides reasonable assurance that air is not passing through the filters and adsorbers.  A program should be developed and consistently applied that defines the terms "painting," "fire," and "chemical release" in terms of the potential fordegrading the HEPA filters and adsorbers.  This program should be based on a well-documented, sound and conservative technical basis (i.e., the criteria should overestimate the potential damage to the filter and adsorber).
9 In Section FD-1130 of ASME AG-1-1997 (Ref. 9), penetration is defined as the exit concentration of a given gas from an aircleaning device, expressed as a percentage of inlet concentration.  In Section 3 of ASME N509-1989 (Ref. 7), bypass is defined as a pathway through which contaminated air can escape treatment by the installed HEPA or adsorber banks.  Examples are leaks in filters and filter mounting frames, defective or inefficient isolation dampers that result in uncontrolled flow through adjacentplenums, and unsealed penetrations for electrical conduits, pipes, floor drains, etc.


1.52-13in-place testing of ESF atmosphere cleanup systems and components should be performed inaccordance with ASME N510-1989 (Ref. 8) as modified and supplemented by the following:
13. IEEE Std 338.1971, "Trial-Use Criteria for the Periodic Testing of Nuclear Power Generating Station Protection Systems." Institute of Electrical and Elec-tronics Engineers.
6.1.Each ESF atmosphere cleanup train should be operated continuously for at least 15minutes each month, with the heaters on (if so equipped), to justify the operability of the system and


all its components.
14. IEEE Std 344-1975, "IEEE Recommended Prac-tices for Seismic Qualification of Class lE Equipment for Nuclear Power Generating Stations," Institute of Electrical and Electronics Engineers.


6.2.A visual inspection of the ESF atmosphere cleanup system and all associatedcomponents should be performed in accordance with Section 5 of ASME N510-1989 (Ref. 8).
15. Regulatory Guide 8.8, "Information Relevant to Maintaining Occupational Radiation Exposure As Low As Is Reasonably Achievable (Nuclear Power Reactors)." Office of Standards Development, USNRC.16. MSAR 71-45, "Entrained Moisture Separators for Fine Particle Water-Air-Steam Service, Their Perfor-mance, Development and Status." Mine Safty. Appli-ance Research Corporation, March 1971.17. Standard UL-900, "Air Filter Units," Under-writers' Laboratories (also designated ANSI B 124.1-1971).
6.3.In-place aerosol leak tests for HEPA filters upstream from the carbon adsorbers inESF atmosphere cleanup systems should be performed (1) initially, (2) at least once each 24
c0.. Underwriters'
Laboratories Building Materials List.19. ASHRAE Standard 52-68, "Method of Testing Air Cleaning Devices Used in General Ventilation for Removing Particulate Matter, Section 9," American Society of Heating, Refrigerating and Air Conditioning Engineers.


months, (3) after each partial or complete replacement of a HEPA filter bank, (4) following detection of, or evidence of, penetration or intrusion of water or other material into any portion of an ESF atmosphere cleanup system that may have an adverse effect on the functional capability of the filters, 7 and (5) following painting, fire, or chemical release in any ventilation zonecommunicating with the system that may have an adverse effect on the functional capability of the system.8  The test should be performed in accordance with Section 10 of ASME N510-1989.  Theleak test should confirm a combined penetration and leakage (or bypass)
20. MIL-F-51068D, "Filter, Particulate.
9 of the ESF atmospherecleanup system of less than 0.05% of the challenge aerosol at rated flow +/-10%.  To be credited with a 99% removal efficiency for particulate matter in accident dose evaluations, a HEPA filter bank in an ESF atmosphere cleanup system should demonstrate an aerosol leak test result of less than
0.05% of the challenge aerosol at rated flow +/-10%.HEPA filter sections in ESF atmosphere cleanup systems that fail to satisfy the appropriateleak-test conditions should be examined to determine the location and cause of leaks.  Repairs, such as alignment of filter frames and tightening of filter hold-down bolts, may be made; however, patching or caulking materials should not be used in the repair of defective, damaged, or torn filter media in ESF atmosphere cleanup systems; such filters should be replaced and not repaire


====d. HEPA====
Iligh-Effi- ciency, Fire-Resistant," Military Specification, 4 April 1974.21. MIlF.51079B, "Filter Medium, Fire-Resistant, High-Efficiency," Military Specification, 29 March 1974.22. Standard UL-586, "High Efficiency, Particulate, Air Filter Units," Underwriters'
filters that fail to satisfy test conditions should be replaced with filters qualified pursuant to Regulatory Position 4.4 of this guide. After repairs or filter replacement, the ESF atmosphere cleanup system should be retested as described above in this Regulatory Positio
Laboratories (also desig-nated ANSI B132.1-1971).
23. USERDA (formally USAEC).Health and Safety Bulletin, "Filter Unit Inspection and Testing Service." U.S. Energy Research and Development Administration.


====n. The above ====
24. MIL-STD-282, "Filter Units, Protective Clothing Gas-Mask Components and Related Products:
10 Care should be taken to ensure that the aerosol generator is compatible with the selected alternative challenge agent (see NRCInformation Notice 99-34 (Ref. 24)).
Perform-ance-Test Methods," Military Standard, 28 May 1956.25. AACC CS-8T, "Tentative Standard for Hligh-Effi.
1.52-14process should be repeated as necessary until combined penetration and leakage (bypass) of thesystem is less than the acceptance criteria described above in this Regulatory Position. In accordance with ASME N510-1989 (Ref. 8) and Article TA-1000 of ASME AG-1-1997(Ref. 9), the standard challenge aerosol used in the in-place leak testing of HEPA filters is polydisperse droplets of dioctyl phthalate (DOP), also known as di-2-ethylhexyl-phthalate (DEHP).
The 0.3 micrometer monodisperse DOP aerosol is used for efficiency testing of individual HEPA
filters by manufacturers and Filter Test stations.  Alternative challenge agents
10 may be used toperform in-place leak-testing of HEPA filters when their selection is based on the following. 1.The challenge aerosol has the approximate light scattering droplet size specified in Article TA-1130 of ASME AG-1-1997 (Ref. 9).2.The challenge aerosol has the same in-place leak test results as DOP.


3.The challenge aerosol has a similar lower detection limit, sensitivity, and precision asDOP.4.The challenge aerosol causes no degradation of the HEPA filter or the other ESF aircleaning system components under test conditions.5.The challenge aerosol is listed in the Environmental Protection Agency's "ToxicSubstance Control Act" (TSCA) (Ref. 25) inventory for commercial use.
ciency Gas-Phase Adsorber Cells," American Association for Contamination Control. July 1972.1.52-7
26. USAEC Report DP.1082, "Standardized Nonde-structive Test of Carbon Beds for Reactor Confinement Application," D.R. Muhlbaier, Savannah River LUbora-tory, July 1967.27. American Conference of Governmental Industrial Hygienists, "Industrial Ventilation," 13th Edition, 1974.28. ASTM D2862-70, 'Test for Particle Size Distri.bution of Granulated Activated Carbon," American Society for Testing and Materials.


6.4.In-place leak testing for adsorbers should be performed (1) initially, (2) at least onceeach 24 months, (3) following removal of an adsorber sample for laboratory testing if the integrity
29. ASTM El 1-70, "Specifications for Wire Cloth Sieves for Testing Purposes," American Society for Testing and Materials.


of the adsorber section is affected, (4) after each partial or complete replacement of carbon adsorber in an adsorber section, (5) following detection of, or evidence of, penetration or intrusion of water or other material into any portion of an ESF atmosphere cleanup system that may have an adverse effect on the functional capability of the adsorber, and (6) following painting, fire, or chemical release in any ventilation zone communicating with the system that may have an adverse effect on the functional capability of the system.
30. RTD Standard M16-IT, "Gas-Phase Adsorbents for Trapping Radioactive Iodine and Iodine Com-pounds," USAEC Division of Reactor Development and Technology, October 1973.31. A.G. Evans, "Effect of Intense Gamma Radiation on Radioiodine Retention by Activated Carbon," CONF-720823, Proceedings of the Twelfth AEC Air Cleaning Conference, 28-31 August 1972.32. ASTM D2854-70, "Test for Apparent Density of Activated Carbon," American Society for Testing and Materials.


8  The test should be performed in accordance with Section11 of ASME N510-1989 (Ref. 8).  The leak test should confirm a combined penetration and leakage (or bypass)
1.52-8 TABLE 1 TYPICAL ACCIDENT CONDITIONS
9 of the adsorber section of 0.05% or less of the challenge gas at rated flow +/-10%.Adsorber sections that fail to satisfy the appropriate leak-test conditions should be examinedto determine the location and cause of leaks. Repairs, such as alignment of adsorber cells, tightening of adsorber cell holddown bolts, or tightening of test canister fixtures, may be made;
FOR ATMOSPHERE
however, the use of temporary patching material on adsorbers, filters, housings, mounting frames, or ducts should not be allowed.  After repairs or adjustments have been made, the adsorber sections should be retested as described above in this Regulatory Position.  The above process should be repeated as necessary until the combined penetration and leakage (bypass) of the adsorber section is less than the acceptance criteria described above in this Regulatory Position.In accordance with ASME N510-1989 (Ref. 8) and Section TA of ASME AG-1-1997 (Ref.9), the standard challenge gas used in the in-place leak testing of adsorbers is Refrigerant-11 (trichloromonofluoromethane).  Alternative challenge gases may be used to perform in-place leak
CLEANUP SYSTEM Environmental Condition Atmosphere Cleanup System Pressure surge Maximum pressure Maximum temperature of influent Relative humidity of influent Primary Result of initial blowdown 60 psi 280" F 100% plus condensing moisture Secondary Generally less than primary" I atilt 180" F I 00A.Average radiation level For airborne radioactive materials
11 For the definition of "representative sample" and a description of sampling methods, see Appendix A of ASME N509-1989(Ref. 7).  
106 rads/hra 105 rad'For-iodine build'p on adsorber 109 radsa 109 rad: Average airborne iodine concentration For elemental iodine 100 mg/m 3  10 mg/r For methyl iodide and particulate iodine 10 mg/m 3 I mg/m aThisvalue isbased on the source term specified in RegulatoryGuide
1.52-15testing of adsorbers, when their selection is based on meeting the characteristics specified inAppendix TA-C of ASME AG-1-1997.
1.3 (Ref. 4)o: 1.4 (Ref. S).asapplicable.


6.5.If any welding repairs are necessary on, within, or adjacent to the ducts, housing, ormounting frames, the HEPA filters and adsorbers should be removed from the housing (or otherwise protected) prior to performing such repairs.  The repairs should be completed prior to re- installation of filters and adsorbers; the system should then be visually inspected and leak tested as in Regulatory Positions 6.2, 6.3, and 6.4.7.LABORATORY TESTING CRITERIA FOR ACTIVATED CARBONLaboratory testing of samples of activated carbon adsorber material from ESF atmospherecleanup systems should be performed in accordance with ASTM D3803-1989 (Ref. 10) and Table 1 of this guide as supplemented by the following: 
s/hr" s2 n 3 3 1.52.9
7.1.If an analysis of unused activated carbon has not been conducted within the past 5years, representative
'2 TABLE 2 PHYSICAL PROPERTIES
11 samples of the unused activated carbon should be collected at the time ofinstallation or replacement of adsorber material and submitted for analysis.  The analysis should be performed in accordance with Regulatory Position 4.11 or Table 1 of this guide, whichever is more restrictive. Carbon that is stored for future use should be stored in its original unopened and undamaged container and stored in a storage area that meets the specifications provided in Subpart
OF NEW ACTIVATED  
CARBON BATCH TESTSa TO BE PERFORMED
ON FINISHED ADSORBENT ACCEPTABLE
TEST METHOD TEST ACCEPTABLE
RESUL iG 1. Particle size distribution
2. Hardness number


2.2 of ASME NQA-1-1997 (Ref. 26). Carbon that does not meet these specifications should not be used without performing an analysis demonstrating its current capability.
===3. Ignition temperature===
4. Activity c S. Radioiodine removal efficiency a. Methyl iodide, 25 0 C and 95% relative humidityd b. Methyl iodide, 80 0 C and 95% relative humidity c. Methyl iodide, in containmente d. Elemental iodine retention 6. Bulk density 7. Impregnant content ASTM D2862 (Ref. 28)RDT M 16-IT, Appendix C (Ref. 30)RDT M16-1T, Appendix C (Ref. 30)CCI 4 Activity, RDT M16-1T.Appendix C (Ref. 30)RDT M 16-1 T (Ref. 30), para. 4.5.3, except 95%relative humidity air is required RDT M 16-IT (Ref. 30), para. 4.5.3, except 80 0 C and 95% relative humidity air is required for test (pre-and post-loading sweep medium is 25 0 C)RDT M16-IT (Ref. 30), para. 4.5.4, except duration is 2 hours at 3.7 atm.pressure Savannah River Laboratory (Ref. 31)ASTM D2854 (Ref. 32)State procedure Retained on #6 ASTM El Ib Sieve: Retained on #8 ASTM El !b Sieve: Through #8, retained on #12 Sieve: Through #12, retained on #16 Sieve: Through #16 ASTM E IIb Sieve: Through #18 ASTM El 1 b Sieve: 95 minimum 0.0%5.0% max.40% to 60%40% to 60%5.0% max.1.0% max.330*C minimum at 100 fpm 60 minimum 99%99%98%99.9% loading 99% loading plus elution 0.38 glml minimum State type (not to exceed 5% by weight)'A "batch test" is a test made on a production batch of a product to establish suitability for a specific application.


7.2.Sampling and analysis should be performed (1) after each 720 hours of systemoperation, or at least once each 24 months, whichever comes first, (2) following painting, fire, or chemical release in any ventilation zone communicating with the system that may have an adverse effect on the functional capability of the carbon media, 8 and (3) following detection of, or evidenceof, penetration or intrusion of water or other material into any portion of an ESF atmosphere cleanup system that may have an adverse effect on the functional capability of the carbon media.
A "batch of activated carbon" is a quantity of material of the same grade, type, and series that has been homogenized to exhibit, within reasonable tolerance, the same performance and physical characteristics and for which the manufacturer can demonstrate by acceptable tests and quality control practices such uniformity.


7.3.For accident dose evaluation purposes, the activated carbon adsorber section of anESF atmosphere cleanup system should be assigned the appropriate decontamination efficiency given in Table 1 for elemental iodine and organic iodides if the following conditions are met:1.The adsorber section meets the leak-test conditions given in Regulatory Position 6.4 ofthis guide.2.New activated carbon meets the performance and physical property specifications givenin Regulatory Position 4.11 of this guide, and3.Representative samples of new or used activated carbon pass the applicable laboratorytests specified in Table 1 of this guide.
All material in the same batch should be activated, impregnated, and otherwise treated under the same process conditions and procedures in the same process equipment and should be produced under the same manufacturing release and instructions.


1.52-16If the activated carbon fails to meet any of the above conditions, it should not be used inadsorbers in ESF atmosphere cleanup systems.
Material produced in the same charge of batch equipment constitutes a batch: material produced in different charges of the same batch equipment should be included in the same batch only if it can be homogenized as above. The maximum batch size should be 350 ft 3 of activated carbo


7.4.The activated carbon adsorber section should be replaced with new unused activatedcarbon that meets the performance and physical property specifications of Regulatory Position 4.11 of this guide if (1) testing in accordance with Regulatory Positions 7.1 and 7.2  results in a representative sample that fails to pass the applicable test in Table 1 of this guide or if (2) no representative sample is available for testing.
====n. bSee Reference ====
29.OThis test should be performed on base material.dThis test should be performed for qualification purposes.


==D. IMPLEMENTATION==
A "qualification test" is a test that establishes the suitability of a product for a general application, normally a one.time test reflecting historical typical performance of material.Chis test should be performed for qualification purposes on carbon to be installed in primary containment (recirculating)
The purpose of this section is to provide information to applicants and licensees regardingthe NRC staff's plans for using this regulatory guide.Except in those cases in which an applicant or licensee proposes an acceptable alternativemethod for complying with specified portions of the NRC's regulations, the methods described in this guide, which reflect public comments, will be used by the NRC staff in its evaluation of submittals in connection with the design, inspection, and testing of post-accident ESF atmosphere cleanup systems for the following light-water-cooled nuclear power plants: 1.Plants for which the construction permit or license application is docketed after theissue date of this guide;2.Plants for which the licensee voluntarily commits to the provisions of this guide.
atmosphere cleanup systems.1.52-10
TABLE 3 LABORATORY
TESTS FOR ACTIVATED
CARBON ACTIVATED
CARBON2 BED DEPTHb 2 Inches. Air filtration system designed to operate inside primary containment.


1.52-17AllowablePenetration[100%OrganicIodideEfficiencyforActivatedCarbonCreditedInLicenseesAccidentAnalysis
2 inches. Air filtration system designed to operate outside the primary containment and relative humidity is controlled to 70%.4 inches or greater. Air filtration system designed to opeiate outside the primary containment and relative humidity is controlled to 70%.ASSIGNED ACTIVATED
]SafetyFactorTable 1:  Laboratory Tests For Activated Carbon Activated Carbon aTotal Bed Depth bMaximum Assigned Credit for Activated CarbonDecontamination EfficienciesMethyl Iodide PenetrationAcceptance Criterion forRepresentative Sample2 inchesElemental iodineOrganic iodide
CARBON DECONTAMINATION
95%95%Penetration 2.5% when tested inaccordance with ASTM D-3803-
EFFICIENCIES
 
Elemental iodine 90%/Organic iodide 30"V1 Elemental iodine 95%Organic iodide 95%Elemental iodine 99%Organic iodide 99%LABORATORY
1989 (Ref. 10)4 inches or greaterElemental iodineOrganic iodide
TESTS FOR A REPRESENTATIVE
99%99%Penetration 0.5% when tested inaccordance with ASTM D-3803-
SAMPLEc Per Test 5.c in Table 2 for a methyl iodide penetration of less than ! 0%.Per Test 5 b in Table 2 at a relative humidity of 707c for a methyl iodide penetration of less than 1%.Per Test 5.b in Table 2 at a relative humidity of 70% for a methyl iodide penetration of less than 0.175%.aThe activated carbon, when new, should meet the specifications of regulatory position C.3.i of this guide.bMuttiple beds, e.g., two 2-inch beds in series, should be treated as a single bed of aggregate depth.eSee regulatory position C.6.b. for definition of representative sample. Testing should be performed
 
(1) initially, (2) at least once per operating cycle thereafter for systems maintained in a standby status or after 720 hours of system operation, and (3) following painting, fire, or chemical release in any ventilation zone communicating with the system.1.52-11}}
1989 (Ref. 10)
a The activated carbon, when new, should meet the specifications of Regulatory Position 4.11 of this guide.
 
b Multiple beds, e.g., two 2-inch beds in series, should be treated as a single bed of aggregate depth.  It is  advantageous when seriesbeds are located in separate housings and individually in-place leak tested.  This aids in mixing the challenge agent and contributesto the accuracy of the test results.
 
NOTES: (1)  Credited decontamination efficiencies (a portion of which includes bypass leakage) are based on 0.25 second residence time per2-inch bed depth.(2)  Organic iodide and elemental iodine are the forms of iodine that are expected to be absorbed by activated carbon during a designbasis accident.  Organic iodide is more difficult for activated carbon to adsorb than elemental iodine.  Therefore, the laboratory testto determine the performance of the activated carbon adsorber is based on organic iodide. Methyl iodide is the organic form of iodine that is used in the laboratory test.(3)  This Table 1 provides acceptable decontamination efficiencies and methyl iodide test penetrations of used activated carbonsamples for laboratory testing. Laboratory tests are conducted in accordance with ASTM D3803-1989 (Ref. 10).  Tests areconducted at a temperature of 30
oC and relative humidity of 95%, except a relative humidity of 70% is used when the air entering thecarbon adsorber is maintained at less than or equal to 70% relative humidity.(4)  See Appendix A to ASME N509-1989 (Ref. 7) for the definition of a representative sample.  Testing should be performed at t hefrequencies specified in Regulatory Position 7.2 of this guide.  Testing should be performed in accordance with ASTM D3803-1989(Ref. 10) at a temperature of 30&deg;C and a relative humidity of 95% (or 70% with humidity control).  Using the following equation from NRC Generic Letter 99-02 (Ref. 27), a safety factor of at least 2 should be applied when determining the appropriate methy liodide penetration acceptance criterion in the Technical Specifications for the representative sample.Humidity control can be provided by heaters or an analysis that demonstrates that the air entering the activated carbon will bemaintained less than or equal to 70% RH under design-basis conditions (e.g., worst-case relative humidity of system inlet air, maximum system design flow rate, normal and off-normal supply voltages).
1.52-18FIGURE 1  Example of a Control Room ESF Atmosphere Cleanup Train aFIGURE 2  Example of a Shield, Annulus, and/or Fuel Building ESF Atmosphere CleanupTrain a a Other acceptable configurations exist; these figures are only provided for conceptual purposes.
 
1 Single copies of regulatory guides, both active and draft, and draft NUREG documents may be obtained free of charge bywriting the Reproduction and Distribution Services Section, OCIO, USNRC, Washington, DC 20555-0001, or by fax to
(301)415-2289, or by email to <DISTRIBUTION@NRC.GOV>.  Active guides may also be purchased from the National Technical Information Service on a standing order basis.  Details on this service may be obtained by writing NTIS, 5285 Port Royal Road, Springfield, VA 22161; telephone (800)553-6847; online <http://www.ntis.gov/ordernow>.  Copies of active anddraft guides are available for inspection or copying for a fee from the NRC Public Document Room at 11555 Rockville Pike, Rockville, MD; the PDR's mailing address is USNRC PDR, Washington, DC 20555; telephone (301)415-4737 or (800)397-
4209; fax (301)415-3548; email <PDR@NRC.GOV>.
2 Copies are available for inspection or copying for a fee from the NRC Public Document Room at 11555 Rockville Pike,Rockville, MD; the PDR's mailing address is USNRC PDR, Washington, DC 20555; telephone (301)415-4737 or (800)397-
4209; fax (301)415-3548; email <PDR@NRC.GOV>.
3 Copies are available at current rates from the U.S. Government Printing Office, P.O. Box 37082, Washington, DC 20402-9328(telephone (202)512-1800); or from the National Technical Information Service at 5285 Port Royal Road, Springfield, VA
22161; telephone (800)553-6847; <http://www.ntis.gov/ordernow>.  Copies are available for inspection or copying for a feefrom the NRC Public Document Room at 11555 Rockville Pike, Rockville, MD; the PDR's mailing address is USNRC PDR,
Washington, DC 20555; telephone (301)415-4737 or (800)397-4209; fax (301)415-3548; email is PDR@NRC.GOV.
 
1.52-19REFERENCES1.USNRC, "Assumptions Used for Evaluating the Potential Radiological Consequences of aLoss of Coolant Accident for Boiling Water Reactors," Regulatory Guide 1.3, Revision 2, June 1974.
 
12.USNRC, "Assumptions Used for Evaluating the Potential Radiological Consequences of aLoss of Coolant Accident for Pressurized Water Reactors," Regulatory Guide 1.4, Revision
2, June 1974.
 
13.J.J. DiNunno et al., "Calculation of Distance Factors for Power and Test Reactor Sites,"USAEC TID-14844, 1962.
 
24.L. Soffer et al., "Accident Source Terms for Light-Water Nuclear Power Plants," NUREG-1465, February 1995.
 
35.USNRC, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents atNuclear Power Reactors," Regulatory Guide 1.183, July 2000.
 
16.USNRC, "Assumptions Used for Evaluating the Potential Radiological Consequences of aFuel Handling Accident in the Fuel Handling and Storage Facility for Boiling and Pressurized Water Reactors," Regulatory Guide 1.25 (AEC Safety Guide 25), March 1972.
 
17.American Society of Mechanical Engineers, "Nuclear Power Plant Air-Cleaning Units andComponents," ASME N509-1989.  Reaffirmed 1996.8.American Society of Mechanical Engineers, "Testing of Nuclear Air-Treatment Systems," ASME N510-1989.  Reaffirmed 1995.9.American Society of Mechanical Engineers, "Code on Nuclear Air and Gas Treatment,"ASME/ANSI AG-1-1997.
 
4 Copies are available at current rates from the National Technical Information Service at 5285 Port Royal Road, Springfield, VA22161; telephone (800)553-6847; <http://www.ntis.gov/ordernow>. 
1.52-2010.American Society for Testing and Materials, "Standard Test Methods for Nuclear-GradeActivated Carbon," ASTM Standard D3803-1989.  Reapproved 1995.11.USNRC, "Seismic Design Classification," Regulatory Guide 1.29, Revision 3, September
1978.112.C. A. Burchsted, J.E. Kahn, and A.B. Fuller, "Nuclear Air Cleaning Handbook," Oak RidgeNational Laboratory, ERDA 76-21, March 31, 1976.
 
413.USNRC, "Criteria for Safety-Related Electric Power Systems for Nuclear Power Plants,"Regulatory Guide 1.32, Revision 2, February 1977.
 
114.Institute of Electrical and Electronics Engineers, "IEEE Standard Criteria for Safety Systemsfor Nuclear Power Generating Stations," IEEE Std 603-1991.15.USNRC, "Environmental Qualification of Certain Electric Equipment Important to Safetyfor Nuclear Power Plants," Regulatory Guide 1.89, Revision 1, June 1984.
 
116.USNRC, "Quality Assurance Requirements for the Installation, Inspection, and Testing ofInstrumentation and Electric Equipment," AEC Safety Guide 1.30, August 1972.
 
117.USNRC, "Seismic Qualification of Electric and Mechanical Equipment for Nuclear PowerPlants," Regulatory Guide 1.100, Revision 2, June 1988.
 
118.USNRC, "Periodic Testing of Electric Power and Protection Systems," Regulatory Guide
1.118, Revision 3, April 1995.
 
119.Institute of Electrical and Electronics Engineers, "IEEE Standard for Type Tests ofContinuous-Duty Class 1E Motors for Nuclear Power Generating Stations," IEEE Std 334-
 
1974.20.USNRC, "Information Relevant to Ensuring that Occupational Radiation Exposures atNuclear Power Stations Will Be As Low As Is Reasonably Achievable," Regulatory Guide
8.8, Revision 3, June1978.
 
121.American Society of Mechanical Engineers, "Code on Nuclear Air and Gas Treatment,"Section HA, "Housings," ASME AG-1a-2000, Addenda to ASME AG-1-1997, December
 
2000.22.J.K. Fretthold, "HEPA Service Life Tests-Effects-Recommendations at Department ofEnergy Rocky Flats Environmental Technology Site," Proceedings of the 25th DOE/NRC
Nuclear Air Cleaning and Treatment Conference, NUREG/CP-0167, April 1999.
 
3  
5 Copies are available at current rates from the U.S. Government Printing Office, P.O. Box 37082, Washington, DC 20402-9328(telephone (202)512-1800).
1.52-2123.NRC Information Notice 99-01, "Deterioration of High-Efficiency Particulate Air Filters ina Pressurized Water Reactor Containment Fan Cooler Unit," January 20, 1999.
 
224.NRC Information Notice 99-34, "Potential Fire Hazards in the Use of Polyalphaolefin inTesting of Air Filters," December 28, 1999.
 
225.Environmental Protection Agency's "Toxic Substance Control Act" (TSCA), Inventory forCommercial Use.
 
526.American Society of Mechanical Engineers, "Quality Assurance Requirements for NuclearFacility Applications," ASME NQA-1-1997.27.NRC Generic Letter 99-02, "Laboratory Testing of Nuclear-Grade Activated Charcoal,"June 3, 1999.
 
2
1.52-22VALUE/IMPACT STATEMENTA value/impact statement was published with the draft of this guide when it was issued forpublic comment (Task DG-1102, October 2000).  No changes were necessary, so a separate value/impact statement for this regulatory guide has not been prepared.  This regulatory guide does not require a backfit analysis as described in 10 CFR 50.109(c) because it does not impose a new or amended provision in the NRC's rules and regulations.  A copy of the value/impact statement (ADAMS Accession Number ML003756180) is available for inspection or copying for a fee in the
 
NRC's Public Document Room at 11555 Rockville Pike, Rockville, MD; the PDR's mailing address is USNRC PDR, Washington, DC 20555; telephone (301)415-4737 or (800)397-4209; fax
 
(301)415-3548; email is <PDR@NRC.GOV>.}}


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Design, Testing, and Maintenance Criteria for Engineered-safety-feature Atmosphere Cleanup System Air Filtration and Adsorption Units of Light-Water-Cooled Nuclear Power Plants
ML13350A197
Person / Time
Issue date: 07/31/1976
From:
Office of Nuclear Regulatory Research
To:
References
RG-1.052, Rev. 1
Download: ML13350A197 (11)
v • d • e


U.S. NUCLEAR REGULATORY

COMMISSION

REGULATORY

GUIDE Revitton 1 July 1976 OFFICE OF STANDARDS

DEVELOPMENT

REGULATORY

GUIDE 1.52 DESIGN, TESTING, AND MAINTENANCE

CRITERIA FOR ENGINEERED-SAFETY-

FEATURE ATMOSPHERE

CLEANUP SYSTEM AIR FILTRATION

AND ADSORPTION

UNITS OF LIGHT-WATER-COOLED

NUCLEAR POWER PLANTS

A. INTRODUCTION

General Design Criteria 41. 42, and 43 of Appendix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50, "Licensing of Production and Utilization Facilities," require that containment atmos-phere cleanup systems be provided as necessary to reduce the amount of radioactive material released to the environment following a postulated design basis accident (DBA) and that these systems be designed to permit appropriate periodic inspection and testing to ensure their integrity, capability, and operability.

General Design Criterion 61 of Appendix A to Part 50 requires that fuel storage and handling systems, radioactive waste systems, and other systems that may contain radioactivity be designed to ensure adequate safety under normal and postulated accident conditions and that they be designed with appropriate confinement, and filtering systems. General Design Criterion 19 requires that adequate radit'ion protection be provided to permit access to and occusaucy of the control room under accident conditions and for the duration of the accident without personnel radiation exposures in excess of 5 I.futo the whole body.This guide pres!"4 nertods acceptable to the NRC staff for implernr-ting" e Commission's regulations in Appendix A, tiO CFl Part 50 with regard to the design, te .g, afti imilinance criteria for air filtration and ada T atmosphere cleanup systems in light-water- ed nuclear power plants. This guide applies onlyy engineered-safety-feature atmosphere cleanup systems designed to mitigate the consequences of postulated accidents.

It addresses the atmosphere cleanup system, including the various components and ductwork, in the postulated DBA environment.

B. DISCUSSION

Atmosphere cleanup systems are included as en-gineered safety features in the design of liglil.witer.

cooled nuclear power plants to mitigate the c0rs,..quences of postulated accldwnts by removing fr',rn the building or conltailliment atmosphere radioactive mnateral that may be rtdeased in the accident.

All such cleanup systems should be dsiped it) operate uider the environnmental conditions resulting from die accideit.in this guide, atmosphere cleanup systems that nitist operate under postulated DBA conditions inside the primary containment (i.e., recirculating systems) are designated as primary systems. Systems required to operate under conditions that are generally less severe (Le., recirculating or once-through systems) are desig-nated as secondary systems. Secondary systems typically include the standby gas treatment system and the emergency air cleaning systems for the fuel handliiig building, control room, and shield building.The DBA environmental conditions for a Liven system should be determined for each plant. DBA environmental conditions for typical primary and secondary systems are shown in Table I. In addition.primary systems should be designed to withstand tie radiation dose from water and plateout sources in the containment and the corrosive effects of chemical sprays (if such sprays are included in the plant design).An atmosphere cleanup system consists of sonic or all of the following components:

demisters, heaters. pre-filters, high-efficiency particulate air (HEPA) filters, adsorption units, fans, and associated ductwork, valv.ing, and instrumentation.

The purpose of the decnister is to remove entrained water droplets from die inlet USNRC AEGULATORY

GUIDES Comments ftould be sent to the Secetatev of the Commit$'*r U 6 Nuclse, Reegulatorl Commission.

Wathington.

0 C 2OU. Attention Doielblim and~Regulatory Guides ate ilsued to describe and make available to the public Service Sectiomt methods eoeet6able to thl NRC ,e:If of implementing specific perts of ihe Commission'e seouleione.

0 adlhnete'

techniques used by the $tlef in vei1u the guides spa Issued in the following ton broad divisions cling specific problems or pOS1ulated accidents, or to piovidte guidance to eppli cen.t Regulatory Guides or* not substitute$ iegulalitlln and complience I Power Reactors 6 Products with them is not (iquired Melthods and solutions dilt cent from those eel ou0 in 2 Research and Telt leactore 1 Transportation the guides w)iI be acceptable it they provide a basis tlo the findings requisite to 3 Fuels end Metesiels Facilities

8 Occupational Htelth the issuance at continuance of a permit or license by the Commission

4 Environmental Silti 2 Antitrust Comments and sugg6esti01l for improvement;

in those guide% ate encouraged

5 Materials enid Pllnt Protection

10 General at ell limes, and guides :ill be revised me epptoprlete to accomrnodate cam ments and Io reflect new information ao edaperince Howovee. comments on Copies Of pubtlthed guides mar be obteined by writen request indicating tire this it #rCeived wilhin about two months aftr 4lte istsuince will be per divisione desired to the U S Nuclear Regulatory Comnseteion Washington DC hiculeil usslUl in evaluating thi neimed to-n e.lrly rvii.On 20%5 Atlentuon Direcio, 011,c of Siendedl enstlopmlntit stream. thereby protecting pretilters, HEPA filters, and adsorbers front water damage awd plugging.

Heaters.when used on secondary systems, normally follow the demisters in the cleanup train and are designed to mix and heat the incoming stream to reduce the stream's relative humidity before it reaches the filters and adsorbers.

Prefihters and HEPA filters are installed to remove particulate matter, which may be radioactive.

Prefilters remove the larger particles and prevent excessive loading of HEPA filters; to some extent dernisters may a!so perform this function.

The HEPA filters remove the fine discrete particulate matter and pass the air stream to the adsorber.

The adsorber removes gaseous iodine (ele.mental iodine and organic iodides) from the air stream.IIEPA filters downstream Df the adsorption units collect carbon fines. The fan is the final item in an atmosphere cleanup train.The environmental conditions preceding a postulated DIA may affect the performance of the atmosphere cleanup system. Such factors, for example, as industrial contaminants, pollutants, temperature, and relative humidity contribute to the aging and weathering of filters and adsorbers and reduce their capability to perform their intended functions.

Therefore, aging and weathering of the filter: and adsorbers, both of which vary from site to site, should be considered during design and operation.

Average temperature and relative humidity also vary from site to site, and the potential buildup of moisture in the adsorber should also be given design consideration.

The effects of these environmental factors on the atmosphere cleanup systemn should be determined by scheduled testing during operation.

All components, of atmosphere cleanup systems should be designed for reliable performance under accident conditions.

Initial testing and proper mainte.nance are primary factors in ensuring the reliability of the system. Careful attention during the design phase to problems of system maintenance can contribute signifi-cantly to the reliability of the system by increasing the ease of such maintenance.

Of particular importance in the design is a layout that provides accessibility and sufficient working space so that the required functions can be performed safely. Periodic testing during opera.Lion to verify the efficiency of the components is another important means of ensuring reliability.

Built-in features that will facilitate convenient in-place testing are important in system design.Standards for the design and testing of atmosphere cleanup systems include draft standard ANSI N509,'Lines indicate substantyv- changes from previously published regulatory guide."Nuclear Power Plant Air Cleaning Units and Comnpo.rients" (Ref. 1), and ANSI N510.1975, "Testing of Nuclear Air Cleaning Systems" (Ref. 2).Other standards are available for the construction and testing of certain components of systems. Where such standards are acceptable to the NRC staff, they are referenced in this guide. Where no suitable standard exists, acceptable approaches are presented in this guide.ORNL.NSIC-65, "Design, Construction and Testing of High-Efficiency Air Filtration Systems for Nuclear Ap-plication" (Ref. 3), provides a comprehensive review of air filtration systems. It is not a standard but a guide that discusses a number of acceptable design alternatives.

C. REGULATORY

POSITION 1. Environmental Design Criteria a. The design of an engineered-safety.feature at.mosphere cleanup system should be based on the maximum pressure differential, radiation dose rate, relative humidity, maximum and minimum temperature, and other conditions resulting from the postulated DBA and on the duration of such conditions.

b. The design of each system should be based on the radiation dose to essential services ih the vicinity of the adsorber section integrated over the 30.day period following the postulated DBA. The radiation source term should be consistent with the assumptions found in Regulatory Guides 1.3 (Ref. 4), 1.4 (Ref. 5), and 1.25 (Ref. 6). Other engineered safety features, incluing pertinent components of essential services such as power, air, and control cables, should be adequately shielded from the atmosphere cleanup systems.c. The design of each adsorber should be based on the concentration and relative abundance of the iodine species (elemental, particulate, and organic), which should be consistent with the assumptions found in Regulatory Guides 1.3 (Ref. 4), 1.4 (Ref. 5), and 1.25 (Ref. 6).d. The operation of any atmosphere cleanup system should not deleteriously affect the operation of other engineered safety features such as a containment spray system, nor should the operation of other en-gineered safety features such as a containment spray system deleteriously affect the operation of any atmos-phere cleanup system.e. Components of systems connected to compart.ments that are unheated during a postulated accident should be designed for postaccident effects of both the lowest and highest outdoor temperatures used in the plant design.*1 1.52-2

2. System Design Criteria a. Atmosphere cleanup systems designed and in.stalled for the purpose of mitigating accident doses should be redundant.

The systems should consist of the following weqt..ntial components:

(1) demisters, (2)prefilters (Gemisters may serve this function), (3) HEPA filters before the adsorbers, (4) iodine adsorbers (impreg.nated activated carbon or equivalent ads.,rbent such as metal zeolites), (5) HIEPA filters after the adsorbers, (6)ducts and valves, (7) fans, and (8) related instrumenta.

tion. Heaters or cooling coils should be used when the humidity is to be controlled before filtration.

b. The redundant atmosphere cleanup systems should be physically separated so that damage to one system does not also cause damage to the second system.The generation of missiles from high-pressure equipment rupture, rotating machinery failure, or natural pheno-mena should be considered in the design for separation and protection.

c. All components of an engineered-safety-feature atmosphere cleanup system should be designated as Seismic Category I (see Regulatory Guide 1.29 (Ref. 7))if failure of a component would lead to the release of significant quantities of Fission products to the working or outdoor environments.

d. If the atmosphere cleanup system is subject to pressure surges resulting from thie postulated accident, the system should be protected from such'surges.

Each component should be protected with such devices as pressure relief valves so that the overall system will perform its intended function during and after the passage of the pressure surge.e. In the mechanical design of the sy: tem, the high radiation levels that may be associated with buildup of radicactive materials on the system components should be given particular consideration.

System con-struction

  • materials should effectively perform their intended function under the postulated radiation levels.The effects of radiation should be considered not only for the demisters, heaters. HEPA fidters, adsorbers, and fans, but also for any electrical insulation, controls, joining compounds, dampers, gaskets, and other organic-containing materials that are necessary for opera-tion during a postulated DBA.f. The volumetric air flow rate of a single cleanup train should be limited to approximately

30,000 cfm. If a total system air flow in excess of this rate is required, multiple trains should be used. For ease of maintenance, a filter layout three HEPA filters high and ten wide is preferred.

g. The atmosphere cleanup system shovld be instrumented to signal. alarm, and record pertinent pressure drops and flow rates at the control room.hi. The power supply and electrical distribution system for the atmosphere cleanup system described in Section C,2.a above should be designed in accordance with Regulatory Guide 1.32 (Ref. 8). All instrumenta- tion and equipment controls should be designed to IEEE Standard 279 (Ref. 9). The system should be qualified and tested under Regulatory Guide 1.89 (Ref. 10). To the extent applicable, Regulatory Guide 1.30 (Ref. I I)and IEEE Standards

334 (Ref. 12), 338 (Ref. 13), and 344 (Ref. 14) should be considered in the design.i. To maintain radiation exposures to operating personnel as low as is reasonably achievable during plant maintenance, atmosphere cleanup systems should be designed to facilitate maintenance in accordance with the guidelines of Regulatory Guide 8.8 (Ref. 15). The cleanup train should be totally enclosed.Each train should be designed and installed in a manner that permits replacennent of the train as an intact unit or as a minimum number of segmented sections without removal of individual components.

j. Outdoor air intake openings should be equipped with louvers, grills, screens, or similar protective devices to minimnize the effects of high winds, rain, snow, ice, trash, and other contaminants on the operation of the system. If the atmosphere surrounding the plant could contain significant environmental contaminants, such as dusts and residues from smoke cleanup systems from adjacent coal burning power plants or industry, the design of the system should consider these contaminants and prevent them from affecting the operation of any atmosphere cleanup system.k. Atmtosphere cleanup system housings and duct-work should be designed to exhibit on test a maximum total leakage rate as defined in Section 4.12 of draft standard ANSI N509 (Ref. 1). Duct and housing leak tests should be performed In accordance with the recommendations of Section 6 of ANSI N510-1975 (Ref. 2).3. Component Design Criteria and Qualification Test-ing a. The demisters installed in engineered-safety- feature atmosphere cleanup systems should meet qualifi-cation requirements similar to those found in MSAR 71.45, "Entrained Moisture Separators for Fine Particle Water-Air-Steam Service, Their Performance, Develop-ment and Status" (Ref. 16). Demisters should meet Underwriters'

Laboratories (UL) Class I (Ref. 17)requirements.

1.52-3 b. Adsorption units function efficiently at a rela-tive humidity of 70%. If heaters are used on sýcondary systems, the heating section should reduce the relative humidity of the !ncoming atmosphere from 100% to 70% during postulated DBA conditions.

A prototype heating element should be qualified under postulatet DBA conditions.

Consideration should be given in system design to mirnumizing heater control malfunction.

The heater stiould not be a potential ignition adsorbent source.c. Materials used in the prefilters should withstand the radiation levels and environmental conditions preva-lent during the postulated DBA. Prefilters should meet UL Class I (Ref. 17) requirements and should be listed in the current UL Building Materials List (Ref. 18). The prefilters should have not less than a 40% atmospheric dust spot efficiency rating (see Section 9 of the ASHRAE Standard 52, "Method of Testing Air Cleaning Devices Used in General Ventilation for Removing Particulate Matter" (Ref. 19)).d. The HEPA filters should be steel cased and designed to military specifications MIJ,-F-51068D (Ref.20) and MIL-F-51079B (Ref. 21). The HEPA filters should satisfy the requirements of UL-586 (Ref. 22).The HEPA filter separators should be capable of withstanding iodine removal sprays if the atmosphere cleanup system will be exposed to such sprays following a DBA. HEPA filters should be tested individually by the appropriate Filter Test Facility listed in the current Energy Research and Development Administration (formerly USAEC) Health and Safety Bulletin for the Filter Unit Inspection and Testing Service (Ref. 23). The Filter Test Facility should test each filter for penetration of dioctyl phthalate (DOP) in accordance with the recommendations of MIL-F-5 1068D (Ref. 20) and MIL-STD-282 (Ref. 24).e. Filter and adsorber mounting frames should be constructed and designed in accordance with the recom-mendations of Section 4.3 of ORNL-NSIC-65 (Ref. 3).f. Filter and adsorber banks should be arranged in accordance with the recommendations of Section 4.4 of ORNL.NSIC-65 (Ref. 3).g. System filter housings, including floors and doors, should be constructed and designed in accor-dance with the recommendations of Sections 4.5.2, 4.5.5, 4.5.7, and 4.5.9 of ORNL-NSIC-65 (Ref. 3).h. Water drains should be designed in accordance with the recommendations of Section 4.5.6 of ORNL-NSIC-65 (Ref. 3).i. The adsorber section of the atmosphere cleanup system may contain any adsorbent material demon-strated to remove gaseous iodine (elemental iodine and organic iodides) from air at the required efficiency.

Since impregnated activated carbon is commonly used, only this adsorbent is discussed in this guide. Each original or replacement batch of impregnated activated carbon used in the adsorber section should meet the qualification and batch test results summarized in Table 2 of this guide. If an adsorbent other than impregnated activated carbon is proposed or if the mesh size distribution is different from the specifications in Table 2, the proposed adsorbent should have demonstrated the capability to perform as well as or better than activated carbon in satisfying the specifications in Table 2.If impregnated activated carbon is used as the adsorbent, the adsorber system should be designed for an average atmosphere residence time of 0.25 sec per two inches of adsorbent bed. The adsorber should have the capacity of loading 2.5 ing of total iodine (radio-active plus stable) per gram of activated carbon. No more than 5% of impregnant

(50 mg of impregnant per gram of carbon) should be used. The radiation stability of the type of carbon specified should be demonstrated and certified (see Section C.L.b of this guide for the design source term).j. If tray or pleated-bed adsorbent canisters are used in the adsorbent section. they should be designed in accordance with the recommendations of CS.8T,"Tentative Standard for High-Efficiency Gas-Phase Ad-sorber Cells" (Ref. 25). The activated carbon should be totally restrained in the adsorber.

A qualification test on a prototype adsorber should be performed in accordance with paragraph

7.4.1 of CS-8T (Ref. 25), except that the safe shutdown earthquake parameters particular to the site should be used. The adsorber should be tested both before and after the qualification test and should show no significant increased penetration when challenged with a gaseous halogenated hydrocarbon refrigerant in accordance with USAEC Report DP-1082 (Ref. 26).To ensure that the adsorber section will contain carbon of uniform packing density, written procedures for filling the adsorber beds should be prepared and followed in accordance with the recommendations of Section 7.4.2 of CS-8T (Ref. 25).k. The design of the adsorber section should consider possible iodine desorption and adsorbent auto-ignition that may result from radioactivity-induced heat in the adsorbent and concomitant temperature rise.Acceptable designs include a low-flow air bleed system, cooling coils, water sprays for the adsorber section, or other cooling mechanisms.

Any cooling mechanism should satisfy the single-failure criterion.

A low-flow air bleed system should satisfy the single-failure criterion for providing low-humidity (less than 70% relative humidity)

cooling air flow.I. The system fan, its mounting, and the ductwork ,connections should be designed and constructed in 1.52-4 accordance with tile recomtmendatioiss ti Section 2.7 kt ORNL.NSIC.65 (Ref. 3).m. The fan or blower used on the cleanup system should be capable of operating under the environlmental conditions postulated, including radiation.

n. Duclwork should be designed in accordance with the recommnendations of Section 2.8 (if ORNL.NSIC.65 (Ref. 3).o. Ducts and housings should be laid out with a minimun of ledges, protrusions, and crevices thac could collect dust and moisture and that could impede personnel or cicate a hazard to then in the performance of their work. Straightening valnes should be installed to ensure representative air flow trmeasurement and uniform flow distribution through cleanup components.

4. Maintenance a. To keep radiation exposures to operating personnel as low as is reasonably achievable, the atnlus-phere cleanup system should be designed to control leakage and permit maintenance in accUrdance with thie guidlines of Regtilatory Guide 8.8 ( Ref. I5).b. Accessibility of components and maintenance should be considered in the design of atmosphere cleanup systems in accordance with the recomninenda- tions of Sections 2.5.2. 2.5.3. and 2.5.4 of ORNL-NSIC-65 (Ref. 3).c. For ease of niaintena ice, tile system design should provide for a minimum of three linear feet from mounting frame to mounting frame between banks of components.

If components are to be replaced, the dimension to be provided should be the rnaxinun¶length of the component plus a minimum of three feet.d. The system design should provide for perma.nent test probes with external connections.

Preferably, the test probes should be manifolded at a single convenient location, with due consideration given to balancing Qf line lengths and diameter to produce eliable test results for refrigerant gas, resistance, flow rate, and DOP testing.e. Each atmosphere cleanup train should be operated at least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per month, with tile heaters on (if so equipped), in order to reduce the buildup of moisture on the adsorbers and HEPA filters, f. The cleanup components (i.e., HEPA filters, prefiiters, and adsorbers)

should not be Installed while active construction is still in progress.5. I~li.l~ce "lesing (Critella a. 'lre .irllospliere cleanup system Should hi tested ii i place I I ) initially.

21 at least once jle tol)eIatiIIg cycle thereaftel tor svstelnis iirauntained ini a st.urmd'.k status or after 720 hoturs of' sh tem tiioelidtio'n, and (31 following paintilng, lire, or chemical release in anw ventilation zoine communicating with the systeml. A\visual i nspecti tit ' t the systeni and all associated components should he wlade before each test ill accol.dance with the recommendationis tot Section 5 of' ANSI N5 10-1975 (Ref. 2).b. The air flow distributiot:

to thie H-EPA fillets, and iodine adsorbers slihtild be tested in place inuutall\and at least once operating cycle thereafter t,11 unilOrmnity.

The distribution should be within +/-- 2` .,1 thie average olow per unit. The testing should 1ic conducted in accordance with the mecomnmerudations ,I Section 9 of "Industrial Ventilation'" (Ref. 2711 ind Section 8 of ANSI N5 10.1975 (Ref'. 2).k. The in-place DOI' test for IHEPA filters should conf'orm to Section 10 of ANSI N510..1975 (Ref. 2t I IEPA filter sections should be tested in place (It initially, (2) at least once per oIperatnig cycle tihcuCattel for systems maintained in a standby s:atus or at'let 7211 hours0.0835 days <br />2.003 hours <br />0.0119 weeks <br />0.00274 months <br /> of svsteln operation, and (3) following paintio.fire, or chemical release in any ventilanton zone conlnlunicaling with tile systemu to Con1irill a petteti.tion of less than 0.051 at rated flow. An engineered- safety-feature air filtrationr system satist' ing this condi.tion can be considered to warrant a )99.7 remoual efficiency for particulates in accident dose evaluaroits.

IIEPA filters that fail to satisfy this condition should IV replaced with filters qualified pursuant to regulathc.

position C.3.d of this guide. If the IHEPA filter bank ", entirely or only partially replaced.

an in-place DO)' teit should be conducted.

If any welding repairs are necessary on. within. ,m adjacent to the ducts, htousing.

or mllournlting frailes. the filters and adsorbers should be removed fronm tile housing during such repairs. The repairs should be completed prior to periodic testing, filter inspection.

arid in-place testing. Tire use of sili,:one sealants or an% othei temporary patching mnateial on filters. housing. nlloullt-ing frames, or ducts should not be allowed.d. The activated carbon adsorber section should be leak tested with a gaseous halogenated hrydrocarbon refrigerant in accordance with Section 12 of ANSI N510-1975 (Ref. 2) to ensure that bypass leakage through the adsorber section is less than 0.05%. During the test the upstream concentration of refrigerant gas should be no greater than 20 pprim. After the test is completed, air flow through tile unit should be main.1.52-5

-. I tained until the residual refrigerant gas in the eltluent is less than 0.01 ppm. Adsorber leak testing should be conducted whenever DOP testing is done.b. Laboratory Testing Criteria for Activated Carbon a. The activated carbon adsorber section of the atmosphere cleanup system should be assigned the decontamination efficiencies given in Table 3 for ele.mental iodine and organic iodides if the following conditions are met: (1) The adsorber section meets the conditions given in regulatory position C.5.d of this guide, (2) New activated carbon meets the physical property specifications gi'.r in Table 2, and (3) Representative samples of used activated carbon pass the laboratory tests given in Table 3.If the activated carbon fails to meet any of the above conditions, it should not be used in engineered- safety-feature adsorbers.

b. The efficiency of the activated carbon adsorber section should be determined by laboratory testing of representative samples of the activated carbon exposed simultaneously to the same service conditions as the aasorber section. Each representative sample should be not less than two inches in both length and diameter, and each sample should have the same qualification and batch test characteristics as the system adsorbent.

There should be a sufficient number of representative samples located in parallel with the adsorber section for estimat-ing the amount of penetration of the system adsorbent throughout its service life. The design of the samplers sh-ould be in accordance with the recommendations of i Appendix A of draft standard ANSI N509 (Ref. I.Where the system activated carbon is greater than two inches deep, each representative sampling station should consist of enough two-inch samples in series to equal the thickness of the system adsorbent.

Once representative samples are removed for laboratory test, their positions in the sampling array should be blocked off.Laboratory tests of representative samples should be conducted, as indicated in Table 3 of this guide, with the test gas flow in the same direction as the flow during service conditions.

Similar laboratory tests should be performed on an adsorbent sample before loading into the adsorbers to establish an initial point for comparison of future test results. The activated carbon adsorber section should be replaced with new unused activated carbon meeting the physical property specifications of Table 2 after the last representative sample has been removed and tested or if any preceding representative sample has failed to pass the tests in Table 3.

0. IMPLEMENTATION

The purpose of thii section is to provide information to applicants and licensees regarding the NRC staff's plans for using this regulatory guide.This guide reflects current NRC staff practice.

There.fore, except in those cases in which the applicant or licensee proposes an acceptable alternative method, the staff will use the method described herein in evaluating an applicant's or licensee's capability for and perform-ance in complying with specified portions of the Commission's regulations until this guide is revised as a result of suggestions from the public or additional staff review.1.52-6 REFERENCES

I. Draft Standard ANSI N509 (Draft 9 -November 1975), "Nuclear Power Plant Air Cleaning Units and Components," American National Standards Institute.

2. ANSI N510-1975, "Testing of Nuclear Air Clean.ing Systems," American National Standards Institute.

3. ORNL-NSIC-65, "Design, Construction, and Test-ing of High-Efficiency Air Filtration Systems for Nuclear Application," Oak Ridge National Laboratory, C.A.Burchsted and A.B. Fuller, January 1970.4. Regulatory Guide 1.3, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Boiling Water Reactors," Office of Standards Development, U.S. Nuclear Regula-tory Commission (USNRC).5. Regulatory Guide 1.4, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water Reactors," Office of Standards Development, USNRC.6. Regulatory Guide 1.25, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Fuel Handling Accident in the Fuel Handling and Storage Facility for Boiling and Pressurized Water Reactors," Office of Standards Development, USNRC.7. Regulatory Guide 1.29, "Seismic Design Classifica- tion," Office of Standards Development, USNRC.8. Regulatory Guide 1.32, "Criteria for Safety-Re- lated Electric Power Systems for Nuclear Power Plants," Office of Standards Development, USNRC.9. IEEE Std 279-1971, "Criteria for Protection Systems for Nuclear Power Generating Stations," Insti-tute of Electrical and Electronics Engineers.

10. Regulatory Guide 1.89, "Qualification of Class IE Equipment for Nuclear Power Plants," Office of Standards Development, USNRC.11. Regulatory Guide 1.30, "Quality Assurance Requirements for the Installation, Inspection, and Test-ing of Instrumentation and Electric Equipment," Office of Standards Development, USNRC.12. IEEE Std 334-1974, "IEEE Standard for Type Tests of Continuous-Duty Class IE Motors for Nuclear Power Generating Stations," Institute of Electrical and Electronics Engineers.

13. IEEE Std 338.1971, "Trial-Use Criteria for the Periodic Testing of Nuclear Power Generating Station Protection Systems." Institute of Electrical and Elec-tronics Engineers.

14. IEEE Std 344-1975, "IEEE Recommended Prac-tices for Seismic Qualification of Class lE Equipment for Nuclear Power Generating Stations," Institute of Electrical and Electronics Engineers.

15. Regulatory Guide 8.8, "Information Relevant to Maintaining Occupational Radiation Exposure As Low As Is Reasonably Achievable (Nuclear Power Reactors)." Office of Standards Development, USNRC.16. MSAR 71-45, "Entrained Moisture Separators for Fine Particle Water-Air-Steam Service, Their Perfor-mance, Development and Status." Mine Safty. Appli-ance Research Corporation, March 1971.17. Standard UL-900, "Air Filter Units," Under-writers' Laboratories (also designated ANSI B 124.1-1971).

c0.. Underwriters'

Laboratories Building Materials List.19. ASHRAE Standard 52-68, "Method of Testing Air Cleaning Devices Used in General Ventilation for Removing Particulate Matter, Section 9," American Society of Heating, Refrigerating and Air Conditioning Engineers.

20. MIL-F-51068D, "Filter, Particulate.

Iligh-Effi- ciency, Fire-Resistant," Military Specification, 4 April 1974.21. MIlF.51079B, "Filter Medium, Fire-Resistant, High-Efficiency," Military Specification, 29 March 1974.22. Standard UL-586, "High Efficiency, Particulate, Air Filter Units," Underwriters'

Laboratories (also desig-nated ANSI B132.1-1971).

23. USERDA (formally USAEC).Health and Safety Bulletin, "Filter Unit Inspection and Testing Service." U.S. Energy Research and Development Administration.

24. MIL-STD-282, "Filter Units, Protective Clothing Gas-Mask Components and Related Products:

Perform-ance-Test Methods," Military Standard, 28 May 1956.25. AACC CS-8T, "Tentative Standard for Hligh-Effi.

ciency Gas-Phase Adsorber Cells," American Association for Contamination Control. July 1972.1.52-7

26. USAEC Report DP.1082, "Standardized Nonde-structive Test of Carbon Beds for Reactor Confinement Application," D.R. Muhlbaier, Savannah River LUbora-tory, July 1967.27. American Conference of Governmental Industrial Hygienists, "Industrial Ventilation," 13th Edition, 1974.28. ASTM D2862-70, 'Test for Particle Size Distri.bution of Granulated Activated Carbon," American Society for Testing and Materials.

29. ASTM El 1-70, "Specifications for Wire Cloth Sieves for Testing Purposes," American Society for Testing and Materials.

30. RTD Standard M16-IT, "Gas-Phase Adsorbents for Trapping Radioactive Iodine and Iodine Com-pounds," USAEC Division of Reactor Development and Technology, October 1973.31. A.G. Evans, "Effect of Intense Gamma Radiation on Radioiodine Retention by Activated Carbon," CONF-720823, Proceedings of the Twelfth AEC Air Cleaning Conference, 28-31 August 1972.32. ASTM D2854-70, "Test for Apparent Density of Activated Carbon," American Society for Testing and Materials.

1.52-8 TABLE 1 TYPICAL ACCIDENT CONDITIONS

FOR ATMOSPHERE

CLEANUP SYSTEM Environmental Condition Atmosphere Cleanup System Pressure surge Maximum pressure Maximum temperature of influent Relative humidity of influent Primary Result of initial blowdown 60 psi 280" F 100% plus condensing moisture Secondary Generally less than primary" I atilt 180" F I 00A.Average radiation level For airborne radioactive materials

106 rads/hra 105 rad'For-iodine build'p on adsorber 109 radsa 109 rad: Average airborne iodine concentration For elemental iodine 100 mg/m 3 10 mg/r For methyl iodide and particulate iodine 10 mg/m 3 I mg/m aThisvalue isbased on the source term specified in RegulatoryGuide

1.3 (Ref. 4)o: 1.4 (Ref. S).asapplicable.

s/hr" s2 n 3 3 1.52.9

'2 TABLE 2 PHYSICAL PROPERTIES

OF NEW ACTIVATED

CARBON BATCH TESTSa TO BE PERFORMED

ON FINISHED ADSORBENT ACCEPTABLE

TEST METHOD TEST ACCEPTABLE

RESUL iG 1. Particle size distribution

2. Hardness number

3. Ignition temperature

4. Activity c S. Radioiodine removal efficiency a. Methyl iodide, 25 0 C and 95% relative humidityd b. Methyl iodide, 80 0 C and 95% relative humidity c. Methyl iodide, in containmente d. Elemental iodine retention 6. Bulk density 7. Impregnant content ASTM D2862 (Ref. 28)RDT M 16-IT, Appendix C (Ref. 30)RDT M16-1T, Appendix C (Ref. 30)CCI 4 Activity, RDT M16-1T.Appendix C (Ref. 30)RDT M 16-1 T (Ref. 30), para. 4.5.3, except 95%relative humidity air is required RDT M 16-IT (Ref. 30), para. 4.5.3, except 80 0 C and 95% relative humidity air is required for test (pre-and post-loading sweep medium is 25 0 C)RDT M16-IT (Ref. 30), para. 4.5.4, except duration is 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at 3.7 atm.pressure Savannah River Laboratory (Ref. 31)ASTM D2854 (Ref. 32)State procedure Retained on #6 ASTM El Ib Sieve: Retained on #8 ASTM El !b Sieve: Through #8, retained on #12 Sieve: Through #12, retained on #16 Sieve: Through #16 ASTM E IIb Sieve: Through #18 ASTM El 1 b Sieve: 95 minimum 0.0%5.0% max.40% to 60%40% to 60%5.0% max.1.0% max.330*C minimum at 100 fpm 60 minimum 99%99%98%99.9% loading 99% loading plus elution 0.38 glml minimum State type (not to exceed 5% by weight)'A "batch test" is a test made on a production batch of a product to establish suitability for a specific application.

A "batch of activated carbon" is a quantity of material of the same grade, type, and series that has been homogenized to exhibit, within reasonable tolerance, the same performance and physical characteristics and for which the manufacturer can demonstrate by acceptable tests and quality control practices such uniformity.

All material in the same batch should be activated, impregnated, and otherwise treated under the same process conditions and procedures in the same process equipment and should be produced under the same manufacturing release and instructions.

Material produced in the same charge of batch equipment constitutes a batch: material produced in different charges of the same batch equipment should be included in the same batch only if it can be homogenized as above. The maximum batch size should be 350 ft 3 of activated carbo

n. bSee Reference

29.OThis test should be performed on base material.dThis test should be performed for qualification purposes.

A "qualification test" is a test that establishes the suitability of a product for a general application, normally a one.time test reflecting historical typical performance of material.Chis test should be performed for qualification purposes on carbon to be installed in primary containment (recirculating)

atmosphere cleanup systems.1.52-10

TABLE 3 LABORATORY

TESTS FOR ACTIVATED

CARBON ACTIVATED

CARBON2 BED DEPTHb 2 Inches. Air filtration system designed to operate inside primary containment.

2 inches. Air filtration system designed to operate outside the primary containment and relative humidity is controlled to 70%.4 inches or greater. Air filtration system designed to opeiate outside the primary containment and relative humidity is controlled to 70%.ASSIGNED ACTIVATED

CARBON DECONTAMINATION

EFFICIENCIES

Elemental iodine 90%/Organic iodide 30"V1 Elemental iodine 95%Organic iodide 95%Elemental iodine 99%Organic iodide 99%LABORATORY

TESTS FOR A REPRESENTATIVE

SAMPLEc Per Test 5.c in Table 2 for a methyl iodide penetration of less than ! 0%.Per Test 5 b in Table 2 at a relative humidity of 707c for a methyl iodide penetration of less than 1%.Per Test 5.b in Table 2 at a relative humidity of 70% for a methyl iodide penetration of less than 0.175%.aThe activated carbon, when new, should meet the specifications of regulatory position C.3.i of this guide.bMuttiple beds, e.g., two 2-inch beds in series, should be treated as a single bed of aggregate depth.eSee regulatory position C.6.b. for definition of representative sample. Testing should be performed

(1) initially, (2) at least once per operating cycle thereafter for systems maintained in a standby status or after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation, and (3) following painting, fire, or chemical release in any ventilation zone communicating with the system.1.52-11


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