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{{#Wiki_filter:U.S. NUCLEAR REGULATORY | {{#Wiki_filter:U.S. NUCLEAR REGULATORY COMMISSION Revitton 1 July 1976 REGULATORY GUIDE | ||
COMMISSION | OFFICE OF STANDARDS DEVELOPMENT | ||
REGULATORY GUIDE 1.52 DESIGN, TESTING, AND MAINTENANCE CRITERIA FOR ENGINEERED-SAFETY- | |||
FEATURE ATMOSPHERE CLEANUP SYSTEM AIR FILTRATION AND | |||
DEVELOPMENT | ADSORPTION UNITS OF LIGHT-WATER-COOLED NUCLEAR POWER PLANTS | ||
REGULATORY | |||
GUIDE 1.52 DESIGN, TESTING, AND MAINTENANCE | |||
CRITERIA FOR ENGINEERED-SAFETY- | |||
FEATURE ATMOSPHERE | |||
CLEANUP SYSTEM AIR FILTRATION | |||
UNITS OF LIGHT-WATER-COOLED | |||
NUCLEAR POWER PLANTS | |||
==A. INTRODUCTION== | ==A. INTRODUCTION== | ||
General Design Criterion | ==B. DISCUSSION== | ||
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 | General Design Criteria 41. 42, and 43 of Appendix Atmosphere cleanup systems are included as en- A, "General Design Criteria for Nuclear Power Plants," gineered safety features in the design of liglil.witer. | ||
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. | |||
to 10 CFR Part 50, "Licensing of Production and cooled nuclear power plants to mitigate the c0rs,.. | |||
Utilization Facilities," require that containment atmos- quences of postulated accldwnts by removing fr',rn the phere cleanup systems be provided as necessary to building or conltailliment atmosphere radioactive mnateral reduce the amount of radioactive material released to that may be rtdeased in the accident. All such cleanup the environment following a postulated design basis systems should be dsiped it) operate uider the accident (DBA) and that these systems be designed to environnmental conditions resulting from die accideit. | |||
permit appropriate periodic inspection and testing to ensure their integrity, capability, and operability. in this guide, atmosphere cleanup systems that nitist operate under postulated DBA conditions inside the General Design Criterion 61 of Appendix A to Part primary containment (i.e., recirculating systems) are | |||
50 requires that fuel storage and handling systems, designated as primary systems. Systems required to radioactive waste systems, and other systems that may operate under conditions that are generally less severe contain radioactivity be designed to ensure adequate (Le., recirculating or once-through systems) are desig- safety under normal and postulated accident conditions nated as secondary systems. Secondary systems typically and that they be designed with appropriate *itainownt, include the standby gas treatment system and the confinement, and filtering systems. General Design emergency air cleaning systems for the fuel handliiig Criterion 19 requires that adequate radit'ion protection building, control room, and shield building. | |||
be provided to permit access to and occusaucy of the control room under accident conditions and for the The DBA environmental conditions for a Liven duration of the accident without personnel radiation system should be determined for each plant. DBA | |||
exposures in excess of 5 I.futo the whole body. environmental conditions for typical primary and secondary systems are shown in Table I. In addition. | |||
This guide pres!"4 nertods acceptable to the NRC primary systems should be designed to withstand tie staff for implernr-ting" e Commission's regulations in radiation dose from water and plateout sources in the Appendix A, tiO CFl Part 50 with regard to the containment and the corrosive effects of chemical sprays design, te .g, afti imilinance criteria for air filtration (if such sprays are included in the plant design). | |||
and ada nt* T atmosphere cleanup systems in light-water- ed nuclear power plants. This guide An atmosphere cleanup system consists of sonic or all applies onlyy engineered-safety-feature atmosphere of the following components: demisters, heaters. pre- cleanup systems designed to mitigate the consequences filters, high-efficiency particulate air (HEPA) filters, of postulated accidents. It addresses the atmosphere adsorption units, fans, and associated ductwork, valv. | |||
cleanup system, including the various components and ing, and instrumentation. The purpose of the decnister is ductwork, in the postulated DBA environment. to remove entrained water droplets from die inlet USNRC AEGULATORY GUIDES Comments ftould be sent to the Secetatev of the Commit$'*r Reegulatorl Commission. Wathington. 0 C 2OU. Attention U 6 Nuclse, 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 $tlef in vei1u the guides spa Issued in the following ton broad divisions cling specific problems or pOS1ulated accidents, or to piovidte guidance to eppli cen.t Regulatory Guides or* not substitute$ t?* 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 *ndSilti 2 Antitrust R*eview Comments and sugg6esti01lfor 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 marbe obteined by writen request indicating tire this Qui*e. 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 "Nuclear Power Plant Air Cleaning Units and Comnpo. | |||
adsorbers front water damage awd plugging. Heaters. rients" (Ref. 1), and ANSI N510.1975, "Testing of when used on secondary systems, normally follow the Nuclear Air Cleaning Systems" (Ref. 2). | |||
demisters in the cleanup train and are designed to mix and heat the incoming stream to reduce the stream's Other standards are available for the construction and relative humidity before it reaches the filters and testing of certain components of systems. Where such adsorbers. standards are acceptable to the NRC staff, they are referenced in this guide. Where no suitable standard Prefihters and HEPA filters are installed to remove exists, acceptable approaches are presented in this guide. | |||
particulate matter, which may be radioactive. Prefilters ORNL.NSIC-65, "Design, Construction and Testing of remove the larger particles and prevent excessive loading High-Efficiency Air Filtration Systems for Nuclear Ap- of HEPA filters; to some extent dernisters may a!so plication" (Ref. 3), provides a comprehensive review of perform this function. The HEPA filters remove the fine air filtration systems. It is not a standard but a guide discrete particulate matter and pass the air stream to the that discusses a number of acceptable design alternatives. | |||
adsorber. The adsorber removes gaseous iodine (ele. | |||
mental iodine and organic iodides) from the air stream. | |||
IIEPA filters downstream Df the adsorption units collect | |||
==C. REGULATORY POSITION== | |||
carbon fines. The fan is the final item in an atmosphere cleanup train. 1. Environmental Design Criteria a. The design of an engineered-safety.feature at. | |||
The environmental conditions preceding a postulated mosphere cleanup system should be based on the DIA may affect the performance of the atmosphere maximum pressure differential, radiation dose rate, cleanup system. Such factors, for example, as industrial relative humidity, maximum and minimum temperature, contaminants, pollutants, temperature, and relative and other conditions resulting from the postulated DBA | |||
humidity contribute to the aging and weathering of filters and adsorbers and reduce their capability to and on the duration of such conditions. | |||
perform their intended functions. Therefore, aging and weathering of the filter: and adsorbers, both of which b. The design of each system should be based on vary from site to site, should be considered during design the radiation dose to essential services ih the vicinity of and operation. Average temperature and relative the adsorber section integrated over the 30.day period humidity also vary from site to site, and the potential following the postulated DBA. The radiation source buildup of moisture in the adsorber should also be given term should be consistent with the assumptions found in design consideration. The effects of these environmental Regulatory Guides 1.3 (Ref. 4), 1.4 (Ref. 5), and factors on the atmosphere cleanup systemn should be 1.25 (Ref. 6). Other engineered safety features, incluing determined by scheduled testing during operation. pertinent components of essential services such as power, air, and control cables, should be adequately shielded from the atmosphere cleanup systems. | |||
All components, of atmosphere cleanup systems should be designed for reliable performance under accident conditions. Initial testing and proper mainte. c. The design of each adsorber should be based on the concentration and relative abundance of the iodine nance are primary factors in ensuring the reliability of species (elemental, particulate, and organic), which the system. Careful attention during the design phase to should be consistent with the assumptions found in problems of system maintenance can contribute signifi- Regulatory Guides 1.3 (Ref. 4), 1.4 (Ref. 5), and 1.25 cantly to the reliability of the system by increasing the (Ref. 6). | |||
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 d. The operation of any atmosphere cleanup can be performed safely. Periodic testing during opera. system should not deleteriously affect the operation of Lion to verify the efficiency of the components is other engineered safety features such as a containment another important means of ensuring reliability. Built-in spray system, nor should the operation of other en- features that will facilitate convenient in-place testing gineered safety features such as a containment spray are important in system design. system deleteriously affect the operation of any atmos- phere cleanup system. | |||
Standards for the design and testing of atmosphere | |||
*1 cleanup systems include draft standard ANSI N509, e. Components of systems connected to compart. | |||
ments that are unheated during a postulated accident should be designed for postaccident effects of both the | |||
'Lines indicate substantyv- changes from previously published lowest and highest outdoor temperatures used in the regulatory guide. plant design. | |||
1.52-2 | |||
The | 2. System Design Criteria g. The atmosphere cleanup system shovld be instrumented to signal. alarm, and record pertinent a. Atmosphere cleanup systems designed and in. pressure drops and flow rates at the control room. | ||
stalled for the purpose of mitigating accident doses should be redundant. The systems should consist of the hi. The power supply and electrical distribution following weqt..ntial components: (1) demisters, (2) system for the atmosphere cleanup system described in prefilters (Gemisters may serve this function), (3) HEPA Section C,2.a above should be designed in accordance filters before the adsorbers, (4) iodine adsorbers (impreg. with Regulatory Guide 1.32 (Ref. 8). All instrumenta- nated activated carbon or equivalent ads.,rbent such as tion and equipment controls should be designed to IEEE | |||
metal zeolites), (5) HIEPA filters after the adsorbers, (6) Standard 279 (Ref. 9). The system should be qualified ducts and valves, (7) fans, and (8) related instrumenta. and tested under Regulatory Guide 1.89 (Ref. 10). To tion. Heaters or cooling coils should be used when the the extent applicable, Regulatory Guide 1.30 (Ref. I I) | |||
humidity is to be controlled before filtration. and IEEE Standards 334 (Ref. 12), 338 (Ref. 13), and | |||
344 (Ref. 14) should be considered in the design. | |||
b. The redundant atmosphere cleanup systems should be physically separated so that damage to one i. To maintain radiation exposures to operating system does not also cause damage to the second system. personnel as low as is reasonably achievable during plant The generation of missiles from high-pressure equipment maintenance, atmosphere cleanup systems should be rupture, rotating machinery failure, or natural pheno- designed to facilitate maintenance in accordance with mena should be considered in the design for separation the guidelines of Regulatory Guide 8.8 (Ref. 15). The and protection. atmosph*re cleanup train should be totally enclosed. | |||
Each train should be designed and installed in a manner c. All components of an engineered-safety-feature that permits replacennent of the train as an intact unit or atmosphere cleanup system should be designated as as a minimum number of segmented sections without Seismic Category I (see Regulatory Guide 1.29 (Ref. 7)) removal of individual components. | |||
if failure of a component would lead to the release of significant quantities of Fission products to the working j. Outdoor air intake openings should be equipped or outdoor environments. with louvers, grills, screens, or similar protective devices d. If the atmosphere cleanup system is subject to to minimnize the effects of high winds, rain, snow, ice, trash, and other contaminants on the operation of the pressure surges resulting from thie postulated accident, system. If the atmosphere surrounding the plant could the system should be protected from such'surges. Each contain significant environmental contaminants, such as component should be protected with such devices as dusts and residues from smoke cleanup systems from pressure relief valves so that the overall system will adjacent coal burning power plants or industry, the perform its intended function during and after the design of the system should consider these contaminants passage of the pressure surge. and prevent them from affecting the operation of any atmosphere cleanup system. | |||
e. In the mechanical design of the sy: tem, the high radiation levels that may be associated with buildup k. Atmtosphere cleanup system housings and duct- of radicactive materials on the system components work should be designed to exhibit on test a maximum should be given particular consideration. System con- total leakage rate as defined in Section 4.12 of draft struction *materials should effectively perform their standard ANSI N509 (Ref. 1). Duct and housing leak intended function under the postulated radiation levels. tests should be performed In accordance with the The effects of radiation should be considered not only recommendations of Section 6 of ANSI N510-1975 for the demisters, heaters. HEPA fidters, adsorbers, and (Ref. 2). | |||
fans, but also for any electrical insulation, controls, joining compounds, dampers, gaskets, and other 3. Component Design Criteria and Qualification Test- organic-containing materials that are necessary for opera- ing tion during a postulated DBA. | |||
a. The demisters installed in engineered-safety- feature atmosphere cleanup systems should meet qualifi- f. The volumetric air flow rate of a single cleanup cation requirements similar to those found in MSAR | |||
train should be limited to approximately 30,000 cfm. If 71.45, "Entrained Moisture Separators for Fine Particle a total system air flow in excess of this rate is required, Water-Air-Steam Service, Their Performance, Develop- multiple trains should be used. For ease of maintenance, ment and Status" (Ref. 16). Demisters should meet a filter layout three HEPA filters high and ten wide is Underwriters' Laboratories (UL) Class I (Ref. 17) | |||
preferred. requirements. | |||
1.52-3 | |||
b. Adsorption units function efficiently at a rela- Since impregnated activated carbon is commonly used, tive humidity of 70%. If heaters are used on sýcondary only this adsorbent is discussed in this guide. Each systems, the heating section should reduce the relative original or replacement batch of impregnated activated humidity of the !ncoming atmosphere from 100% to carbon used in the adsorber section should meet the | |||
70% during postulated DBA conditions. A prototype qualification and batch test results summarized in Table heating element should be qualified under postulatet 2 of this guide. If an adsorbent other than impregnated DBA conditions. Consideration should be given in activated carbon is proposed or if the mesh size system design to mirnumizing heater control malfunction. distribution is different from the specifications in Table The heater stiould not be a potential ignition adsorbent 2, the proposed adsorbent should have demonstrated the source. capability to perform as well as or better than activated carbon in satisfying the specifications in Table 2. | |||
c. Materials used in the prefilters should withstand the radiation levels and environmental conditions preva- If impregnated activated carbon is used as the lent during the postulated DBA. Prefilters should meet adsorbent, the adsorber system should be designed for UL Class I (Ref. 17) requirements and should be listed an average atmosphere residence time of 0.25 sec per in the current UL Building Materials List (Ref. 18). The two inches of adsorbent bed. The adsorber should have prefilters should have not less than a 40% atmospheric the capacity of loading 2.5 ing of total iodine (radio- dust spot efficiency rating (see Section 9 of the active plus stable) per gram of activated carbon. No ASHRAE Standard 52, "Method of Testing Air Cleaning more than 5% of impregnant (50 mg of impregnant per Devices Used in General Ventilation for Removing gram of carbon) should be used. The radiation stability Particulate Matter" (Ref. 19)). of the type of carbon specified should be demonstrated and certified (see Section C.L.b of this guide for the d. The HEPA filters should be steel cased and design source term). | |||
designed to military specifications MIJ,-F-51068D (Ref. | |||
20) and MIL-F-51079B (Ref. 21). The HEPA filters j. If tray or pleated-bed adsorbent canisters are should satisfy the requirements of UL-586 (Ref. 22). used in the adsorbent section. they should be designed in The HEPA filter separators should be capable of accordance with the recommendations of CS.8T, | |||
withstanding iodine removal sprays if the atmosphere "Tentative Standard for High-Efficiency Gas-Phase Ad- cleanup system will be exposed to such sprays following sorber Cells" (Ref. 25). The activated carbon should be a DBA. HEPA filters should be tested individually by the totally restrained in the adsorber. A qualification test on appropriate Filter Test Facility listed in the current a prototype adsorber should be performed in accordance Energy Research and Development Administration with paragraph 7.4.1 of CS-8T (Ref. 25), except that the (formerly USAEC) Health and Safety Bulletin for the safe shutdown earthquake parameters particular to the Filter Unit Inspection and Testing Service (Ref. 23). The site should be used. The adsorber should be tested both Filter Test Facility should test each filter for penetration before and after the qualification test and should show of dioctyl phthalate (DOP) in accordance with the no significant increased penetration when challenged recommendations of MIL-F-5 1068D (Ref. 20) and MIL- with a gaseous halogenated hydrocarbon refrigerant in STD-282 (Ref. 24). accordance with USAEC Report DP-1082 (Ref. 26). | |||
e. Filter and adsorber mounting frames should be To ensure that the adsorber section will contain constructed and designed in accordance with the recom- carbon of uniform packing density, written procedures mendations of Section 4.3 of ORNL-NSIC-65 (Ref. 3). for filling the adsorber beds should be prepared and followed in accordance with the recommendations of f. Filter and adsorber banks should be arranged in Section 7.4.2 of CS-8T (Ref. 25). | |||
accordance with the recommendations of Section 4.4 of ORNL.NSIC-65 (Ref. 3). | |||
k. The design of the adsorber section should g. System filter housings, including floors and consider possible iodine desorption and adsorbent auto- doors, should be constructed and designed in accor- ignition that may result from radioactivity-induced heat dance with the recommendations of Sections 4.5.2, in the adsorbent and concomitant temperature rise. | |||
The | 4.5.5, 4.5.7, and 4.5.9 of ORNL-NSIC-65 (Ref. 3). Acceptable designs include a low-flow air bleed system, cooling coils, water sprays for the adsorber section, or other cooling mechanisms. Any cooling mechanism h. Water drains should be designed in accordance with the recommendations of Section 4.5.6 of ORNL- should satisfy the single-failure criterion. A low-flow air bleed system should satisfy the single-failure criterion NSIC-65 (Ref. 3). | ||
for providing low-humidity (less than 70% relative i. The adsorber section of the atmosphere cleanup humidity) cooling air flow. | |||
system may contain any adsorbent material demon- strated to remove gaseous iodine (elemental iodine and I. The system fan, its mounting, and the ductwork organic iodides) from air at the required efficiency. ,connections should be designed and constructed in | |||
1.52-4 | |||
accordance with tile recomtmendatioiss ti Section 2.7 kt 5. I~li.l~ce "lesing (Critella ORNL.NSIC.65 (Ref. 3). | |||
a. 'lre .irllospliere cleanup system Should hi tested iii place II ) initially. 21 at least once jle tol)eIatiIIg m. The fan or blower used on the cleanup system cycle thereaftel tor svstelnis iirauntained ini a st.urmd'.k should be capable of operating under the environlmental sh tem tiioelidtio'n, and (31 status or after 720 hoturs of' | |||
conditions postulated, including radiation. following paintilng, lire, or chemical release in anw ventilation zoine communicating with the systeml. A\ | |||
n. Duclwork should be designed in accordance visual i nspecti t ' the systeni and all associated tit with the recommnendations of Section 2.8 (if ORNL. | |||
components should he wlade before each test ill accol. | |||
NSIC.65 (Ref. 3). dance with the recommendationis tot Section 5 of' ANSI | |||
N5 10-1975 (Ref. 2). | |||
o. Ducts and housings should be laid out with a minimun of ledges, protrusions, and crevices thac could b. The air flow distributiot: to thie H-EPA fillets, collect dust and moisture and that could impede and iodine adsorbers slihtild be tested in place inuutall\ | |||
personnel or cicate a hazard to then in the performance and at least once per*operating cycle thereafter t,11 of their work. Straightening valnes should be installed to unilOrmnity. The distribution should be within +/--2` .,1 ensure representative air flowtrmeasurement and uniform thie average olow per unit. The testing should 1ic flow distribution through cleanup components. conducted in accordance with the mecomnmerudations ,I | |||
Section 9 of "Industrial Ventilation'" (Ref. 2711 ind | |||
4. Maintenance Section 8 of ANSI N5 10.1975 (Ref'. 2). | |||
a. To keep radiation exposures to operating k. The in-place DOI' test for IHEPA filters should personnel as low as is reasonably achievable, the atnlus- conf'orm to Section 10 of ANSI N510..1975 (Ref. 2t phere cleanup system should be designed to control I IEPA filter sections should be tested in place (It leakage and permit maintenance in accUrdance with thie initially, (2) at least once per oIperatnig cycle tihcuCattel guidlines of Regtilatory Guide 8.8 ( Ref. I5). for systems maintained in a standby s:atus or at'let 7211 hours of svsteln operation, and (3) following paintio. | |||
b. Accessibility of components and maintenance fire, or chemical release in any ventilanton zone should be considered in the design of atmosphere conlnlunicaling with tile systemu to Con1irill a petteti. | |||
cleanup systems in accordance with the recomninenda- tion of less than 0.051 at rated flow. An engineered- tions of Sections 2.5.2. 2.5.3. and 2.5.4 of ORNL- safety-feature air filtrationr system satist' ing this condi. | |||
NSIC-65 (Ref. 3). tion can be considered to warrant a )99.7 remoual efficiency for particulates in accident dose evaluaroits. | |||
c. For ease of niaintena ice, tile system design IIEPA filters that fail to satisfy this condition should IV | |||
should provide for a minimum of three linear feet from replaced with filters qualified pursuant to regulathc. | |||
mounting frame to mounting frame between banks of position C.3.d of this guide. If the IHEPA filter bank ", | |||
components. If components are to be replaced, the entirely or only partially replaced. an in-place DO)' teit dimension to be provided should be the rnaxinun¶ should be conducted. | |||
length of the component plus a minimum of three feet. | |||
d. | If any welding repairs are necessary on. within. ,m d. The system design should provide for perma. adjacent to the ducts, htousing. or mllournlting frailes. the nent test probes with external connections. Preferably, filters and adsorbers should be removed fronm tile the test probes should be manifolded at a single housing during such repairs. The repairs should be convenient location, with due consideration given to completed prior to periodic testing, filter inspection. arid balancing Qf line lengths and diameter to produce in-place testing. Tire use of sili,:one sealants or an% othei eliable test results for refrigerant gas, resistance, flow temporary patching mnateial on filters. housing. nlloullt- rate, and DOP testing. ing frames, or ducts should not be allowed. | ||
Each | e. Each atmosphere cleanup train should be d. The activated carbon adsorber section should operated at least 10 hours per month, with tile heaters be leak tested with a gaseous halogenated hrydrocarbon on (if so equipped), in order to reduce the buildup of refrigerant in accordance with Section 12 of ANSI | ||
moisture on the adsorbers and HEPA filters, N510-1975 (Ref. 2) to ensure that bypass leakage through the adsorber section is less than 0.05%. During f. The cleanup components (i.e., HEPA filters, the test the upstream concentration of refrigerant gas prefiiters, and adsorbers) should not be Installed while should be no greater than 20 pprim. After the test is active construction is still in progress. completed, air flow through tile unit should be main. | |||
1.52-5 | |||
-. I | |||
tained until the residual refrigerant gas in the eltluent is sh-ould be in accordance with the recommendations of i less than 0.01 ppm. Adsorber leak testing should be Appendix A of draft standard ANSI N509 (Ref. I. | |||
conducted whenever DOP testing is done. Where the system activated carbon is greater than two inches deep, each representative sampling station should b. Laboratory Testing Criteria for Activated Carbon consist of enough two-inch samples in series to equal the thickness of the system adsorbent. Once representative a. The activated carbon adsorber section of the samples are removed for laboratory test, their positions atmosphere cleanup system should be assigned the in the sampling array should be blocked off. | |||
decontamination efficiencies given in Table 3 for ele. | |||
mental iodine and organic iodides if the following Laboratory tests of representative samples should conditions are met: | |||
be conducted, as indicated in Table 3 of this guide, with the test gas flow in the same direction as the flow during | |||
(1) The adsorber section meets the conditions given in regulatory position C.5.d of this guide, service conditions. Similar laboratory tests should be performed on an adsorbent sample before loading into | |||
(2) New activated carbon meets the physical the adsorbers to establish an initial point for comparison property specifications gi'.r in Table 2, and of future test results. The activated carbon adsorber section should be replaced with new unused activated | |||
(3) Representative samples of used activated carbon meeting the physical property specifications of carbon pass the laboratory tests given in Table 3. 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. | |||
If the activated carbon fails to meet any of the above conditions, it should not be used in engineered- | |||
===0. IMPLEMENTATION=== | |||
safety-feature adsorbers. | |||
The purpose of thii section is to provide information b. The efficiency of the activated carbon adsorber to applicants and licensees regarding the NRC staff's section should be determined by laboratory testing of plans for using this regulatory guide. | |||
representative samples of the activated carbon exposed simultaneously to the same service conditions as the This guide reflects current NRC staff practice. There. | |||
aasorber section. Each representative sample should be fore, except in those cases in which the applicant or not less than two inches in both length and diameter, licensee proposes an acceptable alternative method, the and each sample should have the same qualification and staff will use the method described herein in evaluating batch test characteristics as the system adsorbent. There an applicant's or licensee's capability for and perform- should be a sufficient number of representative samples ance in complying with specified portions of the located in parallel with the adsorber section for estimat- Commission's regulations until this guide is revised as a ing the amount of penetration of the system adsorbent result of suggestions from the public or additional staff throughout its service life. The design of the samplers review. | |||
1.52-6 | |||
REFERENCES | |||
I. Draft Standard ANSI N509 (Draft 9 - November 13. IEEE Std 338.1971, "Trial-Use Criteria for the | |||
1975), "Nuclear Power Plant Air Cleaning Units and Periodic Testing of Nuclear Power Generating Station Components," American National Standards Institute. Protection Systems." Institute of Electrical and Elec- tronics Engineers. | |||
2. ANSI N510-1975, "Testing of Nuclear Air Clean. | |||
ing Systems," American National Standards Institute. | |||
14. IEEE Std 344-1975, "IEEE Recommended Prac- tices for Seismic Qualification of Class lE Equipment | |||
3. ORNL-NSIC-65, "Design, Construction, and Test- for Nuclear Power Generating Stations," Institute of ing of High-Efficiency Air Filtration Systems for Nuclear Electrical and Electronics Engineers. | |||
Application," Oak Ridge National Laboratory, C.A. | |||
Burchsted and A.B. Fuller, January 1970. 15. Regulatory Guide 8.8, "Information Relevant to Maintaining Occupational Radiation Exposure As Low | |||
4. Regulatory Guide 1.3, "Assumptions Used for As Is Reasonably Achievable (Nuclear Power Reactors)." | |||
Evaluating the Potential Radiological Consequences of a Office of Standards Development, USNRC. | |||
Loss of Coolant Accident for Boiling Water Reactors," | |||
Office of Standards Development, U.S. Nuclear Regula- 16. MSAR 71-45, "Entrained Moisture Separators tory Commission (USNRC). for Fine Particle Water-Air-Steam Service, Their Perfor- mance, Development and Status." Mine Safty. Appli- | |||
5. Regulatory Guide 1.4, "Assumptions Used for ance Research Corporation, March 1971. | |||
Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water 17. Standard UL-900, "Air Filter Units," Under- Reactors," Office of Standards Development, USNRC. writers' Laboratories (also designated ANSI | |||
B 124.1-1971). | |||
6. Regulatory Guide 1.25, "Assumptions Used for Evaluating the Potential Radiological Consequences of a c0..Underwriters' Laboratories Building Materials Fuel Handling Accident in the Fuel Handling and List. | |||
Storage Facility for Boiling and Pressurized Water Reactors," Office of Standards Development, USNRC. 19. ASHRAE Standard 52-68, "Method of Testing Air Cleaning Devices Used in General Ventilation for | |||
7. Regulatory Guide 1.29, "Seismic Design Classifica- Removing Particulate Matter, Section 9," American tion," Office of Standards Development, USNRC. Society of Heating, Refrigerating and Air Conditioning Engineers. | |||
8. Regulatory Guide 1.32, "Criteria for Safety-Re- 20. MIL-F-51068D, "Filter, Particulate. Iligh-Effi- lated Electric Power Systems for Nuclear Power Plants," | |||
ciency, Fire-Resistant," Military Specification, 4 April Office of Standards Development, USNRC. 1974. | |||
9. IEEE Std 279-1971, "Criteria for Protection 21. MIlF.51079B, "Filter Medium, Fire-Resistant, Systems for Nuclear Power Generating Stations," Insti- High-Efficiency," Military Specification, 29 March 1974. | |||
tute of Electrical and Electronics Engineers. | |||
22. Standard UL-586, "High Efficiency, Particulate, Air Filter Units," Underwriters' Laboratories (also desig- | |||
10. Regulatory Guide 1.89, "Qualification of Class nated ANSI B132.1-1971). | |||
IE Equipment for Nuclear Power Plants," Office of Standards Development, USNRC. 23. USERDA (formally USAEC).Health and Safety Bulletin, "Filter Unit Inspection and Testing Service." | |||
11.Regulatory Guide 1.30, "Quality Assurance U.S. Energy Research and Development Administration. | |||
Requirements for the Installation, Inspection, and Test- ing of Instrumentation and Electric Equipment," Office of Standards Development, USNRC. 24. MIL-STD-282, "Filter Units, Protective Clothing Gas-Mask Components and Related Products: Perform- ance-Test Methods," Military Standard, 28 May 1956. | |||
12. IEEE Std 334-1974, "IEEE Standard for Type Tests of Continuous-Duty Class IE Motors for Nuclear 25. AACC CS-8T, "Tentative Standard for Hligh-Effi. | |||
Power Generating Stations," Institute of Electrical and ciency Gas-Phase Adsorber Cells," American Association Electronics Engineers. for Contamination Control. July 1972. | |||
1.52-7 | |||
26. USAEC Report DP.1082, "Standardized Nonde- 30. RTD Standard M16-IT, "Gas-Phase Adsorbents structive Test of Carbon Beds for Reactor Confinement for Trapping Radioactive Iodine and Iodine Com- Application," D.R. Muhlbaier, Savannah River LUbora- pounds," USAEC Division of Reactor Development and tory, July 1967. Technology, October 1973. | |||
27. American Conference of Governmental Industrial Hygienists, "Industrial Ventilation," 13th Edition, 1974. 31. A.G. Evans, "Effect of Intense Gamma Radiation on Radioiodine Retention by Activated Carbon," | |||
28. ASTM D2862-70, 'Test for Particle Size Distri. CONF-720823, Proceedings of the Twelfth AEC Air bution of Granulated Activated Carbon," American Cleaning Conference, 28-31 August 1972. | |||
Society for Testing and Materials. | |||
29. ASTM El 1-70, "Specifications for Wire Cloth 32. ASTM D2854-70, "Test for Apparent Density of Sieves for Testing Purposes," American Society for Activated Carbon," American Society for Testing and Testing and Materials. Materials. | |||
1.52-8 | |||
TABLE 1 TYPICAL ACCIDENT CONDITIONS FOR ATMOSPHERE CLEANUP SYSTEM | |||
Environmental Condition Atmosphere Cleanup System Primary Secondary Pressure surge Result of initial blowdown Generally less than primary Maximum pressure 60 psi " I atilt Maximum temperature of influent 280" F 180" F | |||
Relative humidity of influent 100% plus condensing I00A. | |||
moisture Average radiation level For airborne radioactive materials 106 rads/hra 105 rad' s/hr" | |||
For-iodine build'p on adsorber 109 radsa 109 rad:s2 Average airborne iodine concentration For elemental iodine 100 mg/m 3 10 mg/r n 3 For methyl iodide and particulate iodine 10 mg/m 3 I mg/m 3 aThisvalue isbased on the source term specified in RegulatoryGuide 1.3 (Ref. 4)o: 1.4 (Ref. S).asapplicable. | |||
1.52.9 | |||
TABLE 2 PHYSICAL PROPERTIES OF NEW ACTIVATED CARBON | |||
BATCH TESTSa TO BE PERFORMED ON FINISHED ADSORBENT | |||
ACCEPTABLE TEST | |||
TEST METHOD ACCEPTABLE RESUL iG | |||
1. Particle size distribution ASTM D2862 (Ref. 28) Retained on #6 ASTM El Ib Sieve: 0.0% | |||
Retained on #8 ASTM El !b Sieve: 5.0% max. | |||
Through #8, retained on #12 Sieve: 40% to 60% | |||
Through #12, retained on #16 Sieve: 40% to 60% | |||
Through #16 ASTM E IIb Sieve: 5.0%max. | |||
Through #18 ASTM El 1 b Sieve: 1.0% max. | |||
2. Hardness number RDT M16-IT, Appendix C | |||
(Ref. 30) 95 minimum | |||
3. Ignition temperature RDT M16-1T, Appendix C | |||
(Ref. 30) 330*C minimum at 100 fpm | |||
4. Activity c CCI 4 Activity, RDT M16-1T. | |||
Appendix C (Ref. 30) 60 minimum S. Radioiodine removal efficiency a. Methyl iodide, 250 C RDT M16-1 T (Ref. 30), 99% | |||
and 95% relative para. 4.5.3, except 95% | |||
humidityd relative humidity air is required b. Methyl iodide, 80 0 C RDT M 16-IT (Ref. 30), 99% | |||
and 95% relative para. 4.5.3, except 80 0 C | |||
humidity and 95% relative humidity air is required for test (pre- and post-loading sweep medium is 25 0C) | |||
c. Methyl iodide, in RDT M16-IT (Ref. 30), 98% | |||
containmente para. 4.5.4, except duration | |||
'2 is 2 hours at 3.7 atm. | |||
pressure d. Elemental iodine Savannah River 99.9% loading retention Laboratory (Ref. 31) 99% loading plus elution | |||
6. Bulk density ASTM D2854 (Ref. 32) 0.38 glml minimum | |||
7. Impregnant content State procedure 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 carbon. | |||
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 ASSIGNED ACTIVATED CARBON LABORATORY TESTS FOR A | |||
BED DEPTHb DECONTAMINATION EFFICIENCIES REPRESENTATIVE SAMPLEc | |||
2 Inches. Air filtration system Elemental iodine 90%/ Per Test 5.c in Table 2 for a methyl designed to operate inside primary Organic iodide 30"V1 iodide penetration of less than ! 0%. | |||
containment. | |||
2 inches. Air filtration system Elemental iodine 95% Per Test 5 b in Table 2 at a relative designed to operate outside the Organic iodide 95% humidity of 707c for a methyl primary containment and relative iodide penetration of less than 1%. | |||
humidity is controlled to 70%. | |||
4 inches or greater. Air filtration Elemental iodine 99% Per Test 5.b in Table 2 at a relative system designed to opeiate outside Organic iodide 99% humidity of 70% for a methyl the primary containment and iodide penetration of less than relative humidity is controlled to 0.175%. | |||
70%. | |||
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}} | |||
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Revision as of 10:24, 4 November 2019
ML13350A197 | |
Person / Time | |
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Issue date: | 07/31/1976 |
From: | Office of Nuclear Regulatory Research |
To: | |
References | |
RG-1.052, Rev. 1 | |
Download: ML13350A197 (11) | |
U.S. NUCLEAR REGULATORY COMMISSION Revitton 1 July 1976 REGULATORY GUIDE
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
B. DISCUSSION
General Design Criteria 41. 42, and 43 of Appendix Atmosphere cleanup systems are included as en- A, "General Design Criteria for Nuclear Power Plants," gineered safety features in the design of liglil.witer.
to 10 CFR Part 50, "Licensing of Production and cooled nuclear power plants to mitigate the c0rs,..
Utilization Facilities," require that containment atmos- quences of postulated accldwnts by removing fr',rn the phere cleanup systems be provided as necessary to building or conltailliment atmosphere radioactive mnateral reduce the amount of radioactive material released to that may be rtdeased in the accident. All such cleanup the environment following a postulated design basis systems should be dsiped it) operate uider the accident (DBA) and that these systems be designed to environnmental conditions resulting from die accideit.
permit appropriate periodic inspection and testing to ensure their integrity, capability, and operability. in this guide, atmosphere cleanup systems that nitist operate under postulated DBA conditions inside the General Design Criterion 61 of Appendix A to Part primary containment (i.e., recirculating systems) are
50 requires that fuel storage and handling systems, designated as primary systems. Systems required to radioactive waste systems, and other systems that may operate under conditions that are generally less severe contain radioactivity be designed to ensure adequate (Le., recirculating or once-through systems) are desig- safety under normal and postulated accident conditions nated as secondary systems. Secondary systems typically and that they be designed with appropriate *itainownt, include the standby gas treatment system and the confinement, and filtering systems. General Design emergency air cleaning systems for the fuel handliiig Criterion 19 requires that adequate radit'ion protection building, control room, and shield building.
be provided to permit access to and occusaucy of the control room under accident conditions and for the The DBA environmental conditions for a Liven duration of the accident without personnel radiation system should be determined for each plant. DBA
exposures in excess of 5 I.futo the whole body. environmental conditions for typical primary and secondary systems are shown in Table I. In addition.
This guide pres!"4 nertods acceptable to the NRC primary systems should be designed to withstand tie staff for implernr-ting" e Commission's regulations in radiation dose from water and plateout sources in the Appendix A, tiO CFl Part 50 with regard to the containment and the corrosive effects of chemical sprays design, te .g, afti imilinance criteria for air filtration (if such sprays are included in the plant design).
and ada nt* T atmosphere cleanup systems in light-water- ed nuclear power plants. This guide An atmosphere cleanup system consists of sonic or all applies onlyy engineered-safety-feature atmosphere of the following components: demisters, heaters. pre- cleanup systems designed to mitigate the consequences filters, high-efficiency particulate air (HEPA) filters, of postulated accidents. It addresses the atmosphere adsorption units, fans, and associated ductwork, valv.
cleanup system, including the various components and ing, and instrumentation. The purpose of the decnister is ductwork, in the postulated DBA environment. to remove entrained water droplets from die inlet USNRC AEGULATORY GUIDES Comments ftould be sent to the Secetatev of the Commit$'*r Reegulatorl Commission. Wathington. 0 C 2OU. Attention U 6 Nuclse, 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 $tlef in vei1u the guides spa Issued in the following ton broad divisions cling specific problems or pOS1ulated accidents, or to piovidte guidance to eppli cen.t Regulatory Guides or* not substitute$ t?* 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 *ndSilti 2 Antitrust R*eview Comments and sugg6esti01lfor 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 marbe obteined by writen request indicating tire this Qui*e. 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 "Nuclear Power Plant Air Cleaning Units and Comnpo.
adsorbers front water damage awd plugging. Heaters. rients" (Ref. 1), and ANSI N510.1975, "Testing of when used on secondary systems, normally follow the Nuclear Air Cleaning Systems" (Ref. 2).
demisters in the cleanup train and are designed to mix and heat the incoming stream to reduce the stream's Other standards are available for the construction and relative humidity before it reaches the filters and testing of certain components of systems. Where such adsorbers. standards are acceptable to the NRC staff, they are referenced in this guide. Where no suitable standard Prefihters and HEPA filters are installed to remove exists, acceptable approaches are presented in this guide.
particulate matter, which may be radioactive. Prefilters ORNL.NSIC-65, "Design, Construction and Testing of remove the larger particles and prevent excessive loading High-Efficiency Air Filtration Systems for Nuclear Ap- of HEPA filters; to some extent dernisters may a!so plication" (Ref. 3), provides a comprehensive review of perform this function. The HEPA filters remove the fine air filtration systems. It is not a standard but a guide discrete particulate matter and pass the air stream to the that discusses a number of acceptable design alternatives.
adsorber. The adsorber removes gaseous iodine (ele.
mental iodine and organic iodides) from the air stream.
IIEPA filters downstream Df the adsorption units collect
C. REGULATORY POSITION
carbon fines. The fan is the final item in an atmosphere cleanup train. 1. Environmental Design Criteria a. The design of an engineered-safety.feature at.
The environmental conditions preceding a postulated mosphere cleanup system should be based on the DIA may affect the performance of the atmosphere maximum pressure differential, radiation dose rate, cleanup system. Such factors, for example, as industrial relative humidity, maximum and minimum temperature, contaminants, pollutants, temperature, and relative and other conditions resulting from the postulated DBA
humidity contribute to the aging and weathering of filters and adsorbers and reduce their capability to and on the duration of such conditions.
perform their intended functions. Therefore, aging and weathering of the filter: and adsorbers, both of which b. The design of each system should be based on vary from site to site, should be considered during design the radiation dose to essential services ih the vicinity of and operation. Average temperature and relative the adsorber section integrated over the 30.day period humidity also vary from site to site, and the potential following the postulated DBA. The radiation source buildup of moisture in the adsorber should also be given term should be consistent with the assumptions found in design consideration. The effects of these environmental Regulatory Guides 1.3 (Ref. 4), 1.4 (Ref. 5), and factors on the atmosphere cleanup systemn should be 1.25 (Ref. 6). Other engineered safety features, incluing determined by scheduled testing during operation. pertinent components of essential services such as power, air, and control cables, should be adequately shielded from the atmosphere cleanup systems.
All components, of atmosphere cleanup systems should be designed for reliable performance under accident conditions. Initial testing and proper mainte. c. The design of each adsorber should be based on the concentration and relative abundance of the iodine nance are primary factors in ensuring the reliability of species (elemental, particulate, and organic), which the system. Careful attention during the design phase to should be consistent with the assumptions found in problems of system maintenance can contribute signifi- Regulatory Guides 1.3 (Ref. 4), 1.4 (Ref. 5), and 1.25 cantly to the reliability of the system by increasing the (Ref. 6).
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 d. The operation of any atmosphere cleanup can be performed safely. Periodic testing during opera. system should not deleteriously affect the operation of Lion to verify the efficiency of the components is other engineered safety features such as a containment another important means of ensuring reliability. Built-in spray system, nor should the operation of other en- features that will facilitate convenient in-place testing gineered safety features such as a containment spray are important in system design. system deleteriously affect the operation of any atmos- phere cleanup system.
Standards for the design and testing of atmosphere
- 1 cleanup systems include draft standard ANSI N509, e. Components of systems connected to compart.
ments that are unheated during a postulated accident should be designed for postaccident effects of both the
'Lines indicate substantyv- changes from previously published lowest and highest outdoor temperatures used in the regulatory guide. plant design.
1.52-2
2. System Design Criteria g. The atmosphere cleanup system shovld be instrumented to signal. alarm, and record pertinent a. Atmosphere cleanup systems designed and in. pressure drops and flow rates at the control room.
stalled for the purpose of mitigating accident doses should be redundant. The systems should consist of the hi. The power supply and electrical distribution following weqt..ntial components: (1) demisters, (2) system for the atmosphere cleanup system described in prefilters (Gemisters may serve this function), (3) HEPA Section C,2.a above should be designed in accordance filters before the adsorbers, (4) iodine adsorbers (impreg. with Regulatory Guide 1.32 (Ref. 8). All instrumenta- nated activated carbon or equivalent ads.,rbent such as tion and equipment controls should be designed to IEEE
metal zeolites), (5) HIEPA filters after the adsorbers, (6) Standard 279 (Ref. 9). The system should be qualified ducts and valves, (7) fans, and (8) related instrumenta. and tested under Regulatory Guide 1.89 (Ref. 10). To tion. Heaters or cooling coils should be used when the the extent applicable, Regulatory Guide 1.30 (Ref. I I)
humidity is to be controlled before filtration. and IEEE Standards 334 (Ref. 12), 338 (Ref. 13), and
344 (Ref. 14) should be considered in the design.
b. The redundant atmosphere cleanup systems should be physically separated so that damage to one i. To maintain radiation exposures to operating system does not also cause damage to the second system. personnel as low as is reasonably achievable during plant The generation of missiles from high-pressure equipment maintenance, atmosphere cleanup systems should be rupture, rotating machinery failure, or natural pheno- designed to facilitate maintenance in accordance with mena should be considered in the design for separation the guidelines of Regulatory Guide 8.8 (Ref. 15). The and protection. atmosph*re cleanup train should be totally enclosed.
Each train should be designed and installed in a manner c. All components of an engineered-safety-feature that permits replacennent of the train as an intact unit or atmosphere cleanup system should be designated as as a minimum number of segmented sections without Seismic Category I (see Regulatory Guide 1.29 (Ref. 7)) removal of individual components.
if failure of a component would lead to the release of significant quantities of Fission products to the working j. Outdoor air intake openings should be equipped or outdoor environments. with louvers, grills, screens, or similar protective devices d. If the atmosphere cleanup system is subject to to minimnize the effects of high winds, rain, snow, ice, trash, and other contaminants on the operation of the pressure surges resulting from thie postulated accident, system. If the atmosphere surrounding the plant could the system should be protected from such'surges. Each contain significant environmental contaminants, such as component should be protected with such devices as dusts and residues from smoke cleanup systems from pressure relief valves so that the overall system will adjacent coal burning power plants or industry, the perform its intended function during and after the design of the system should consider these contaminants passage of the pressure surge. and prevent them from affecting the operation of any atmosphere cleanup system.
e. In the mechanical design of the sy: tem, the high radiation levels that may be associated with buildup k. Atmtosphere cleanup system housings and duct- of radicactive materials on the system components work should be designed to exhibit on test a maximum should be given particular consideration. System con- total leakage rate as defined in Section 4.12 of draft struction *materials should effectively perform their standard ANSI N509 (Ref. 1). Duct and housing leak intended function under the postulated radiation levels. tests should be performed In accordance with the The effects of radiation should be considered not only recommendations of Section 6 of ANSI N510-1975 for the demisters, heaters. HEPA fidters, adsorbers, and (Ref. 2).
fans, but also for any electrical insulation, controls, joining compounds, dampers, gaskets, and other 3. Component Design Criteria and Qualification Test- organic-containing materials that are necessary for opera- ing tion during a postulated DBA.
a. The demisters installed in engineered-safety- feature atmosphere cleanup systems should meet qualifi- f. The volumetric air flow rate of a single cleanup cation requirements similar to those found in MSAR
train should be limited to approximately 30,000 cfm. If 71.45, "Entrained Moisture Separators for Fine Particle a total system air flow in excess of this rate is required, Water-Air-Steam Service, Their Performance, Develop- multiple trains should be used. For ease of maintenance, ment and Status" (Ref. 16). Demisters should meet a filter layout three HEPA filters high and ten wide is Underwriters' Laboratories (UL) Class I (Ref. 17)
preferred. requirements.
1.52-3
b. Adsorption units function efficiently at a rela- Since impregnated activated carbon is commonly used, tive humidity of 70%. If heaters are used on sýcondary only this adsorbent is discussed in this guide. Each systems, the heating section should reduce the relative original or replacement batch of impregnated activated humidity of the !ncoming atmosphere from 100% to carbon used in the adsorber section should meet the
70% during postulated DBA conditions. A prototype qualification and batch test results summarized in Table heating element should be qualified under postulatet 2 of this guide. If an adsorbent other than impregnated DBA conditions. Consideration should be given in activated carbon is proposed or if the mesh size system design to mirnumizing heater control malfunction. distribution is different from the specifications in Table The heater stiould not be a potential ignition adsorbent 2, the proposed adsorbent should have demonstrated the source. capability to perform as well as or better than activated carbon in satisfying the specifications in Table 2.
c. Materials used in the prefilters should withstand the radiation levels and environmental conditions preva- If impregnated activated carbon is used as the lent during the postulated DBA. Prefilters should meet adsorbent, the adsorber system should be designed for UL Class I (Ref. 17) requirements and should be listed an average atmosphere residence time of 0.25 sec per in the current UL Building Materials List (Ref. 18). The two inches of adsorbent bed. The adsorber should have prefilters should have not less than a 40% atmospheric the capacity of loading 2.5 ing of total iodine (radio- dust spot efficiency rating (see Section 9 of the active plus stable) per gram of activated carbon. No ASHRAE Standard 52, "Method of Testing Air Cleaning more than 5% of impregnant (50 mg of impregnant per Devices Used in General Ventilation for Removing gram of carbon) should be used. The radiation stability Particulate Matter" (Ref. 19)). of the type of carbon specified should be demonstrated and certified (see Section C.L.b of this guide for the d. The HEPA filters should be steel cased and design source term).
designed to military specifications MIJ,-F-51068D (Ref.
20) and MIL-F-51079B (Ref. 21). The HEPA filters j. If tray or pleated-bed adsorbent canisters are should satisfy the requirements of UL-586 (Ref. 22). used in the adsorbent section. they should be designed in The HEPA filter separators should be capable of accordance with the recommendations of CS.8T,
withstanding iodine removal sprays if the atmosphere "Tentative Standard for High-Efficiency Gas-Phase Ad- cleanup system will be exposed to such sprays following sorber Cells" (Ref. 25). The activated carbon should be a DBA. HEPA filters should be tested individually by the totally restrained in the adsorber. A qualification test on appropriate Filter Test Facility listed in the current a prototype adsorber should be performed in accordance Energy Research and Development Administration with paragraph 7.4.1 of CS-8T (Ref. 25), except that the (formerly USAEC) Health and Safety Bulletin for the safe shutdown earthquake parameters particular to the Filter Unit Inspection and Testing Service (Ref. 23). The site should be used. The adsorber should be tested both Filter Test Facility should test each filter for penetration before and after the qualification test and should show of dioctyl phthalate (DOP) in accordance with the no significant increased penetration when challenged recommendations of MIL-F-5 1068D (Ref. 20) and MIL- with a gaseous halogenated hydrocarbon refrigerant in STD-282 (Ref. 24). accordance with USAEC Report DP-1082 (Ref. 26).
e. Filter and adsorber mounting frames should be To ensure that the adsorber section will contain constructed and designed in accordance with the recom- carbon of uniform packing density, written procedures mendations of Section 4.3 of ORNL-NSIC-65 (Ref. 3). for filling the adsorber beds should be prepared and followed in accordance with the recommendations of f. Filter and adsorber banks should be arranged in Section 7.4.2 of CS-8T (Ref. 25).
accordance with the recommendations of Section 4.4 of ORNL.NSIC-65 (Ref. 3).
k. The design of the adsorber section should g. System filter housings, including floors and consider possible iodine desorption and adsorbent auto- doors, should be constructed and designed in accor- ignition that may result from radioactivity-induced heat dance with the recommendations of Sections 4.5.2, in the adsorbent and concomitant temperature rise.
4.5.5, 4.5.7, and 4.5.9 of ORNL-NSIC-65 (Ref. 3). Acceptable designs include a low-flow air bleed system, cooling coils, water sprays for the adsorber section, or other cooling mechanisms. Any cooling mechanism h. Water drains should be designed in accordance with the recommendations of Section 4.5.6 of ORNL- should satisfy the single-failure criterion. A low-flow air bleed system should satisfy the single-failure criterion NSIC-65 (Ref. 3).
for providing low-humidity (less than 70% relative i. The adsorber section of the atmosphere cleanup humidity) cooling air flow.
system may contain any adsorbent material demon- strated to remove gaseous iodine (elemental iodine and I. The system fan, its mounting, and the ductwork organic iodides) from air at the required efficiency. ,connections should be designed and constructed in
1.52-4
accordance with tile recomtmendatioiss ti Section 2.7 kt 5. I~li.l~ce "lesing (Critella ORNL.NSIC.65 (Ref. 3).
a. 'lre .irllospliere cleanup system Should hi tested iii place II ) initially. 21 at least once jle tol)eIatiIIg m. The fan or blower used on the cleanup system cycle thereaftel tor svstelnis iirauntained ini a st.urmd'.k should be capable of operating under the environlmental sh tem tiioelidtio'n, and (31 status or after 720 hoturs of'
conditions postulated, including radiation. following paintilng, lire, or chemical release in anw ventilation zoine communicating with the systeml. A\
n. Duclwork should be designed in accordance visual i nspecti t ' the systeni and all associated tit with the recommnendations of Section 2.8 (if ORNL.
components should he wlade before each test ill accol.
NSIC.65 (Ref. 3). dance with the recommendationis tot Section 5 of' ANSI
N5 10-1975 (Ref. 2).
o. Ducts and housings should be laid out with a minimun of ledges, protrusions, and crevices thac could b. The air flow distributiot: to thie H-EPA fillets, collect dust and moisture and that could impede and iodine adsorbers slihtild be tested in place inuutall\
personnel or cicate a hazard to then in the performance and at least once per*operating cycle thereafter t,11 of their work. Straightening valnes should be installed to unilOrmnity. The distribution should be within +/--2` .,1 ensure representative air flowtrmeasurement and uniform thie average olow per unit. The testing should 1ic flow distribution through cleanup components. conducted in accordance with the mecomnmerudations ,I
Section 9 of "Industrial Ventilation'" (Ref. 2711 ind
4. Maintenance Section 8 of ANSI N5 10.1975 (Ref'. 2).
a. To keep radiation exposures to operating k. The in-place DOI' test for IHEPA filters should personnel as low as is reasonably achievable, the atnlus- conf'orm to Section 10 of ANSI N510..1975 (Ref. 2t phere cleanup system should be designed to control I IEPA filter sections should be tested in place (It leakage and permit maintenance in accUrdance with thie initially, (2) at least once per oIperatnig cycle tihcuCattel guidlines of Regtilatory Guide 8.8 ( Ref. I5). 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.
b. Accessibility of components and maintenance fire, or chemical release in any ventilanton zone should be considered in the design of atmosphere conlnlunicaling with tile systemu to Con1irill a petteti.
cleanup systems in accordance with the recomninenda- tion of less than 0.051 at rated flow. An engineered- tions of Sections 2.5.2. 2.5.3. and 2.5.4 of ORNL- safety-feature air filtrationr system satist' ing this condi.
NSIC-65 (Ref. 3). tion can be considered to warrant a )99.7 remoual efficiency for particulates in accident dose evaluaroits.
c. For ease of niaintena ice, tile system design IIEPA filters that fail to satisfy this condition should IV
should provide for a minimum of three linear feet from replaced with filters qualified pursuant to regulathc.
mounting frame to mounting frame between banks of position C.3.d of this guide. If the IHEPA filter bank ",
components. If components are to be replaced, the entirely or only partially replaced. an in-place DO)' teit dimension to be provided should be the rnaxinun¶ should be conducted.
length of the component plus a minimum of three feet.
If any welding repairs are necessary on. within. ,m d. The system design should provide for perma. adjacent to the ducts, htousing. or mllournlting frailes. the nent test probes with external connections. Preferably, filters and adsorbers should be removed fronm tile the test probes should be manifolded at a single housing during such repairs. The repairs should be convenient location, with due consideration given to completed prior to periodic testing, filter inspection. arid balancing Qf line lengths and diameter to produce in-place testing. Tire use of sili,:one sealants or an% othei eliable test results for refrigerant gas, resistance, flow temporary patching mnateial on filters. housing. nlloullt- rate, and DOP testing. ing frames, or ducts should not be allowed.
e. Each atmosphere cleanup train should be d. The activated carbon adsorber section should 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 be leak tested with a gaseous halogenated hrydrocarbon on (if so equipped), in order to reduce the buildup of refrigerant in accordance with Section 12 of ANSI
moisture on the adsorbers and HEPA filters, N510-1975 (Ref. 2) to ensure that bypass leakage through the adsorber section is less than 0.05%. During f. The cleanup components (i.e., HEPA filters, the test the upstream concentration of refrigerant gas prefiiters, and adsorbers) should not be Installed while should be no greater than 20 pprim. After the test is active construction is still in progress. completed, air flow through tile unit should be main.
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-. I
tained until the residual refrigerant gas in the eltluent is sh-ould be in accordance with the recommendations of i less than 0.01 ppm. Adsorber leak testing should be Appendix A of draft standard ANSI N509 (Ref. I.
conducted whenever DOP testing is done. Where the system activated carbon is greater than two inches deep, each representative sampling station should b. Laboratory Testing Criteria for Activated Carbon consist of enough two-inch samples in series to equal the thickness of the system adsorbent. Once representative a. The activated carbon adsorber section of the samples are removed for laboratory test, their positions atmosphere cleanup system should be assigned the in the sampling array should be blocked off.
decontamination efficiencies given in Table 3 for ele.
mental iodine and organic iodides if the following Laboratory tests of representative samples should conditions are met:
be conducted, as indicated in Table 3 of this guide, with the test gas flow in the same direction as the flow during
(1) The adsorber section meets the conditions given in regulatory position C.5.d of this guide, service conditions. Similar laboratory tests should be performed on an adsorbent sample before loading into
(2) New activated carbon meets the physical the adsorbers to establish an initial point for comparison property specifications gi'.r in Table 2, and of future test results. The activated carbon adsorber section should be replaced with new unused activated
(3) Representative samples of used activated carbon meeting the physical property specifications of carbon pass the laboratory tests given in Table 3. 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.
If the activated carbon fails to meet any of the above conditions, it should not be used in engineered-
0. IMPLEMENTATION
safety-feature adsorbers.
The purpose of thii section is to provide information b. The efficiency of the activated carbon adsorber to applicants and licensees regarding the NRC staff's section should be determined by laboratory testing of plans for using this regulatory guide.
representative samples of the activated carbon exposed simultaneously to the same service conditions as the This guide reflects current NRC staff practice. There.
aasorber section. Each representative sample should be fore, except in those cases in which the applicant or not less than two inches in both length and diameter, licensee proposes an acceptable alternative method, the and each sample should have the same qualification and staff will use the method described herein in evaluating batch test characteristics as the system adsorbent. There an applicant's or licensee's capability for and perform- should be a sufficient number of representative samples ance in complying with specified portions of the located in parallel with the adsorber section for estimat- Commission's regulations until this guide is revised as a ing the amount of penetration of the system adsorbent result of suggestions from the public or additional staff throughout its service life. The design of the samplers review.
1.52-6
REFERENCES
I. Draft Standard ANSI N509 (Draft 9 - November 13. IEEE Std 338.1971, "Trial-Use Criteria for the
1975), "Nuclear Power Plant Air Cleaning Units and Periodic Testing of Nuclear Power Generating Station Components," American National Standards Institute. Protection Systems." Institute of Electrical and Elec- tronics Engineers.
2. ANSI N510-1975, "Testing of Nuclear Air Clean.
ing Systems," American National Standards Institute.
14. IEEE Std 344-1975, "IEEE Recommended Prac- tices for Seismic Qualification of Class lE Equipment
3. ORNL-NSIC-65, "Design, Construction, and Test- for Nuclear Power Generating Stations," Institute of ing of High-Efficiency Air Filtration Systems for Nuclear Electrical and Electronics Engineers.
Application," Oak Ridge National Laboratory, C.A.
Burchsted and A.B. Fuller, January 1970. 15. Regulatory Guide 8.8, "Information Relevant to Maintaining Occupational Radiation Exposure As Low
4. Regulatory Guide 1.3, "Assumptions Used for As Is Reasonably Achievable (Nuclear Power Reactors)."
Evaluating the Potential Radiological Consequences of a Office of Standards Development, USNRC.
Loss of Coolant Accident for Boiling Water Reactors,"
Office of Standards Development, U.S. Nuclear Regula- 16. MSAR 71-45, "Entrained Moisture Separators tory Commission (USNRC). for Fine Particle Water-Air-Steam Service, Their Perfor- mance, Development and Status." Mine Safty. Appli-
5. Regulatory Guide 1.4, "Assumptions Used for ance Research Corporation, March 1971.
Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water 17. Standard UL-900, "Air Filter Units," Under- Reactors," Office of Standards Development, USNRC. writers' Laboratories (also designated ANSI
B 124.1-1971).
6. Regulatory Guide 1.25, "Assumptions Used for Evaluating the Potential Radiological Consequences of a c0..Underwriters' Laboratories Building Materials Fuel Handling Accident in the Fuel Handling and List.
Storage Facility for Boiling and Pressurized Water Reactors," Office of Standards Development, USNRC. 19. ASHRAE Standard 52-68, "Method of Testing Air Cleaning Devices Used in General Ventilation for
7. Regulatory Guide 1.29, "Seismic Design Classifica- Removing Particulate Matter, Section 9," American tion," Office of Standards Development, USNRC. Society of Heating, Refrigerating and Air Conditioning Engineers.
8. Regulatory Guide 1.32, "Criteria for Safety-Re- 20. MIL-F-51068D, "Filter, Particulate. Iligh-Effi- lated Electric Power Systems for Nuclear Power Plants,"
ciency, Fire-Resistant," Military Specification, 4 April Office of Standards Development, USNRC. 1974.
9. IEEE Std 279-1971, "Criteria for Protection 21. MIlF.51079B, "Filter Medium, Fire-Resistant, Systems for Nuclear Power Generating Stations," Insti- High-Efficiency," Military Specification, 29 March 1974.
tute of Electrical and Electronics Engineers.
22. Standard UL-586, "High Efficiency, Particulate, Air Filter Units," Underwriters' Laboratories (also desig-
10. Regulatory Guide 1.89, "Qualification of Class nated ANSI B132.1-1971).
IE Equipment for Nuclear Power Plants," Office of Standards Development, USNRC. 23. USERDA (formally USAEC).Health and Safety Bulletin, "Filter Unit Inspection and Testing Service."
11.Regulatory Guide 1.30, "Quality Assurance U.S. Energy Research and Development Administration.
Requirements for the Installation, Inspection, and Test- ing of Instrumentation and Electric Equipment," Office of Standards Development, USNRC. 24. MIL-STD-282, "Filter Units, Protective Clothing Gas-Mask Components and Related Products: Perform- ance-Test Methods," Military Standard, 28 May 1956.
12. IEEE Std 334-1974, "IEEE Standard for Type Tests of Continuous-Duty Class IE Motors for Nuclear 25. AACC CS-8T, "Tentative Standard for Hligh-Effi.
Power Generating Stations," Institute of Electrical and ciency Gas-Phase Adsorber Cells," American Association Electronics Engineers. for Contamination Control. July 1972.
1.52-7
26. USAEC Report DP.1082, "Standardized Nonde- 30. RTD Standard M16-IT, "Gas-Phase Adsorbents structive Test of Carbon Beds for Reactor Confinement for Trapping Radioactive Iodine and Iodine Com- Application," D.R. Muhlbaier, Savannah River LUbora- pounds," USAEC Division of Reactor Development and tory, July 1967. Technology, October 1973.
27. American Conference of Governmental Industrial Hygienists, "Industrial Ventilation," 13th Edition, 1974. 31. A.G. Evans, "Effect of Intense Gamma Radiation on Radioiodine Retention by Activated Carbon,"
28. ASTM D2862-70, 'Test for Particle Size Distri. CONF-720823, Proceedings of the Twelfth AEC Air bution of Granulated Activated Carbon," American Cleaning Conference, 28-31 August 1972.
Society for Testing and Materials.
29. ASTM El 1-70, "Specifications for Wire Cloth 32. ASTM D2854-70, "Test for Apparent Density of Sieves for Testing Purposes," American Society for Activated Carbon," American Society for Testing and Testing and Materials. Materials.
1.52-8
TABLE 1 TYPICAL ACCIDENT CONDITIONS FOR ATMOSPHERE CLEANUP SYSTEM
Environmental Condition Atmosphere Cleanup System Primary Secondary Pressure surge Result of initial blowdown Generally less than primary Maximum pressure 60 psi " I atilt Maximum temperature of influent 280" F 180" F
Relative humidity of influent 100% plus condensing I00A.
moisture Average radiation level For airborne radioactive materials 106 rads/hra 105 rad' s/hr"
For-iodine build'p on adsorber 109 radsa 109 rad:s2 Average airborne iodine concentration For elemental iodine 100 mg/m 3 10 mg/r n 3 For methyl iodide and particulate iodine 10 mg/m 3 I mg/m 3 aThisvalue isbased on the source term specified in RegulatoryGuide 1.3 (Ref. 4)o: 1.4 (Ref. S).asapplicable.
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TABLE 2 PHYSICAL PROPERTIES OF NEW ACTIVATED CARBON
BATCH TESTSa TO BE PERFORMED ON FINISHED ADSORBENT
ACCEPTABLE TEST
TEST METHOD ACCEPTABLE RESUL iG
1. Particle size distribution ASTM D2862 (Ref. 28) Retained on #6 ASTM El Ib Sieve: 0.0%
Retained on #8 ASTM El !b Sieve: 5.0% max.
Through #8, retained on #12 Sieve: 40% to 60%
Through #12, retained on #16 Sieve: 40% to 60%
Through #16 ASTM E IIb Sieve: 5.0%max.
Through #18 ASTM El 1 b Sieve: 1.0% max.
2. Hardness number RDT M16-IT, Appendix C
(Ref. 30) 95 minimum
3. Ignition temperature RDT M16-1T, Appendix C
(Ref. 30) 330*C minimum at 100 fpm
4. Activity c CCI 4 Activity, RDT M16-1T.
Appendix C (Ref. 30) 60 minimum S. Radioiodine removal efficiency a. Methyl iodide, 250 C RDT M16-1 T (Ref. 30), 99%
and 95% relative para. 4.5.3, except 95%
humidityd relative humidity air is required b. Methyl iodide, 80 0 C RDT M 16-IT (Ref. 30), 99%
and 95% relative para. 4.5.3, except 80 0 C
humidity and 95% relative humidity air is required for test (pre- and post-loading sweep medium is 25 0C)
c. Methyl iodide, in RDT M16-IT (Ref. 30), 98%
containmente para. 4.5.4, except duration
'2 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 d. Elemental iodine Savannah River 99.9% loading retention Laboratory (Ref. 31) 99% loading plus elution
6. Bulk density ASTM D2854 (Ref. 32) 0.38 glml minimum
7. Impregnant content State procedure 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 carbon.
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 ASSIGNED ACTIVATED CARBON LABORATORY TESTS FOR A
BED DEPTHb DECONTAMINATION EFFICIENCIES REPRESENTATIVE SAMPLEc
2 Inches. Air filtration system Elemental iodine 90%/ Per Test 5.c in Table 2 for a methyl designed to operate inside primary Organic iodide 30"V1 iodide penetration of less than ! 0%.
containment.
2 inches. Air filtration system Elemental iodine 95% Per Test 5 b in Table 2 at a relative designed to operate outside the Organic iodide 95% humidity of 707c for a methyl primary containment and relative iodide penetration of less than 1%.
humidity is controlled to 70%.
4 inches or greater. Air filtration Elemental iodine 99% Per Test 5.b in Table 2 at a relative system designed to opeiate outside Organic iodide 99% humidity of 70% for a methyl the primary containment and iodide penetration of less than relative humidity is controlled to 0.175%.
70%.
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