ini - . ,. **1 . . TOFI ORNLP 2405 .... .. . . 4.74 present -- - - . 245 ; 150 96 UNIT : woman + MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS -1963 i SEP 2 2 1961 ORNL-P-2405 , Conf-660904-8 CFSTI PRICES AC $1.00; MN 50 PERFORMANCE OF FILTER SYSTEMS UNDER ACCIDENT CONDITIONS* R. E. Adams, J. S. Gill, W. D. Yuille, W. E. Browning, Jr., L. F. Parsly, and C. E. Guthrie Reactor Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee LEGAL NOTICE . .. . . .. . This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or s'epresentation, expressed or implied, with respect to the accu- racy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not Infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report, As used in the above, "person acting on behalf of the Comuajsalon" includes any em- ployee or contractor of the Commission, or employee of such contractor, to the extent that RELEASED FOR ANNOUNCEMENT IN NUCLEAR SCIENCE ABSTRACT:S disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor, *Research sponsored by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation. Outline I. Development of a Method for Simulating Reactor Accident Aerosols A. Procedure - Arc Generator B. Characterization of Arc-Generated Aerosols II. Efficiency of High Efficiency Filters for an Arc-Generated Uo, Aerosol A. Dry Atmosphere B. Moist Atmosphere III.. Effect of Moisture on Aerosol Behavior IV. Filter Tests in the Nuclear Safety Pilot Plant A. Run 10 B. Run 3.1 C. Run 12 D. Run 14 V. Comments VI. References 2. PERFORMANCE OF FILTER SYSTEMS UNDER ACCIDENT CONDITIONS R. E. Adams, J. S. Gill, W. D. Yuille, W. E. Browning, Jr., L. F. Parsly, and C. E. Guthrie Siting of nuclear power reactors is at the present time strongly influenced by the potential hazard of released fission products and orly partial credit can be taken for gas cleaning systems. This is due, in part, to a lack of confidence in the performance of filter systems under reactor accident conditions and under subsequent accident environment. It is the purpose of this ORNL program to investigate under simulated accident conditions the effectiveness of various gas cleaning media and systems for removing particulate dispersions expected in accidents to reactors of various types. Because of the multiplicity of variables which must be investigated the major part of this study is being conducted on a laboratory scale using aerosols of proven validity as simulants. A limited number of larger-scale filter tests are being conducted in conjunction with experimental runs at the Nuclear Safety Pilot Plant (NSPP). In the laboratory the work has included the development of a simple method for generating a simulant aeroso.1, tests of these aerosols to determine their validity as simulants, and measurements of the efficiency of absolute filter media for removing these simulant aerosols. Four tests have been accomplished in conjunction with the NSPP program. DEVELOPMENT OF A METHOD FOR SIMULATING REACTOR ACCIDENT AEROSOLS Procedure - Arc Generator A method was developed to generate in the laboratory an aerosol which is similar to aerosols generated in in-pile experiments as well as in the NSPP. A high-intensity arc, powered by a welding machine and struck between electrodes which simulate fuel materials, was investigated for this purpose. To date, tests have been conducted using arcs struck between carbon and stainless steel, *Visiting scientist from United Kingdom Atomic Energy Authority. i t keis ... ... . -2- .. .. carbon and stainless steel tubing packed with ZrO2, two Zircaloy-2 rods, . thoriated tungsten and a uo, rod, two vo, electrodes, and between vo, and a stainless steel tube packed with voz. The last electrode pair 18 the most pronising from the stardpoint of duplicating reactor accident conditions, but other pairs were useful in developing the technique and may be applied to specialized cases (e.g., simulation of vaporization of Zircaloy-clad fuel materials). An aerosol generated from voz and a stainless steel tube packed with von will be described. A satisfactory Uo, electrode 18 made by inserting a thoriated tungsten rod into powered Uo2 which is contained in a steel tube and by supplying sufficient current to the two electrodes to melt the vog. The tungsten rod, when lifted from the bed of voz, will have an irregularly silaped piece of fused to, adhering to it. A convenient size stainless steel tube, closed at one end and packed with Vog, serves as the other electrode. This procedure ensures that the aerosol generated by the arc will contain only UO, and oxidized stainless steel particulates. The to, on tungsten electrode may be shielded in an inert gas to reduce its rate of burnup. Before starting the arc, it is necessary to establish a spark discharge across the gap .. . .. - .. - - - : De... separating the two electrodes. This discharge is generated by a high frequency oscillator connected to one of the electrodes. A5 to 400 amp variable direct - current i welding machine is used to generate the arc. The intensity of the arc, and therefore the degree of melting of the electrodes and the concentration of aerosol generated, is determined by the current. The arc has been maintained for periods of up to 20 min at low current and for lesser periods at higher currents. As the anode (positive electrode) 1s consumed, the gap between electrodes becomes greater until it is too large for the arc to be maintained. r - siti e W R S I A R -3- The cathode shielded in an inert gas is not appreciably consumed. The appearance of the electrodes of vo, and of a stainless steel tube packed with vo, after an arc has been struck between them is shown in Fig. 1.. These electrodes are in reusable condition. In essence, this procedure duplicates those conditions giving rise to aerosol production in a reactor accident, i.e., overheated uo, in the presence of molten stainless steel in an appropriate atmosphere. Characterizatica of Arc-Generated Aerosols Experiments are being conducted to test the validity of the use of arc- generated aerosols as simulants for reactor accident aerosols by characterizing further the particle size distribution of the arc-generated aerosols produced under various conditions. The principal tool for this study is the fibrous filter analyzer (FFA) being developed at this Laboratory(+) as a method for characterizing aerosols by determining their penetration into a series of porous filter mats of uniform-diameter Dacroh'fibers. The transport of an aerosol through an array of fibers brings into play the processes of inertial impaction, interception, and diffusion. Since all these processes have important effects on the behavior of radioactive materials in gas cleaning systems, it is useful to be able to characterize radioactive aerosols by observing their behavior in fibrous beds. This unit 18 schematically represented in Fig. 2. Supplementary information is being collected through use of the electron microscope. Early experiments indicated that when the aerosol from the vo, electrode system was processed through a fibrous-filter analyzer, two distinct particle size distributions were noted; this behavior was also noted in s ubsequent experiments. The distribution between size groups averages about 90% for the larger particles (Component A) and 10% for the smaller particles (Component B). 4- As an example, Fig. 3 illustrates the distribution of particles in a helium atmosphere from an electrode pair consisting of a vo, bead on tungsten and von powder contained in an irradiated stainless steel tube. The compound nature of the distribution curves in Fig. 3, as evidenced by the lines having two distinct slopes, indicates the presence of two fairly distinct particle size groups in the aerosol. The similarity between curves indicates that the uranium and stainless steel are contained in or on the same particle or agglomerate. An electron micrograph from a similar experiment is presented as Fig. 4. The presence of single particles having a particle size ranging from 0.012 to 0.075 u (median size, 0.018 u) and of agglomerates should be noted. A particle size distribution (as determined fron an electron microphotograph) of a similar aerosol is presented as Fig. 5. Particle size groups at the upper and lower limit of this size range could account for the distribution shown in Fig. 3. The form of the uranium after volatilization in the arc was also studied. Under conditions where no oxygen is present (purified helium atmosphere), the uranium exists as UQ2; however, if oxygen is present, the predominant form 18 UzOg. The filtration behavior of each type was identical. In either form the simulant aerosol has been adequate for the needs of this study. The similarity between aerosols produced by the arc technique and those produced by the in-pile melting of nuclear fuel is evidenced by their behavior in a fibrous-filter analyzer. For example, the distribution of cesium in Fig. 6 for the aerosol produced by in-pile fuel melting is quite similar to the distribution in Fig. 3, in that the presence of two particle size groups is indicated by the two distinct lines in the distribution pattern, and further the relative quantities of the two size groups are similar. This, together with electron microscope data, indicates that these arc-produced aerosols are sufficiently similar to aerosols produced by fuel melting to quality as simulants for use in the laboratory. EFFICIENCY OF HIGH EFFICIENCY FILTERS FOR AN ARC-GENERATED UO, AEROSOL Dry Atmosphere The effectiveness of samples of media from commercially-available high efficiency filters in removing simulated reactor accident aerosols is being tested under a filter eve.luation program. In a typical test, an aerosol generated at two vo, electrodes was swept) through a glass chamber (Fig. 7) by a stream of dry filtered air. Approximately 11 in. from the electrodes, the air stream (containing the aerosol) was split. One-half of the stream passed into a filter-pack (white tubes, Fig. 7) which contained a disc of high efficiercy filter material, followed by ten Dacron filters of the FFA. The other half of the stream passed through ten Dacron filters of the FFA. This technique permits simultaneous filter evaluation and aerosol characterization. The material collected on the filters was analyzed for uranium by activation analysis using a delayed-neutron counting technique). The method is based on the fact that delayed neutrons are emitted from fission products produced by the interaction of neutrons with 2350 in the vog. In the present experiments, uranium containing 3% 2950 was used. With the proper choice of irradiation and counting times, a sensitivity of 1000 counts per 10~98 of 255U is obtained. The method can be used to analyze samples containing 10 to 10° ug of 30. - - The distribution of the arc-generated particulate in the Dacron filters - both preceded and not preceded by a high efficiency filters is shown in Fig. 8. As mentioned above, it appears that particles are distributed through the ten Dacron filters in at least two distinct size distributions, A and B. Mathematical -5- .ee . -. - analysis of the data from the experiment shows that the high efficiency filter has a filtration efficiency of > 99.99% for component A and > 99.91% for component B, under the experimental conditions described above. Subsequent experiments were conducted on aerosols generated from vo, and stainless steel packed with vo, electrodes since that combination should most closely simulate melting of a reactor fuel rod. The analytical technique described above was altered in order to analyze for both uranium and stainless steel. Stainless steel was activated in a reactor and cooled to eliminate short-lived products. The major remaining activity was 5tcr. When this stainless steel is used in combination with Uo, to produce an aerosol, the resultant particulate on Dacron f1.ters may be counted to determine stainless steel content, and analyzed for uranium by activation analysis using delayed- neutron counting techniques. Thus, it was possible to determine filter efficiencies for the various sizes of particles containing the stainless steel and the vog: The distribution of a smaller concentration of arc-generated particles in - - - . Dacron filters preceded and not preceded by a high efficiency absolute filter is shown in Fig. 9. In this experiment a U20g aerosol was used, and its concentration was made low by manipulation of the arc intensity. As mentioned above, it appears that particles are distributed through the ten Dacron filters in at least two distinct size distributions, A and B. Mathematical analysis of the data from the experiment showed that the Flanders absolute filter had a filtration efficiency of greater than 99.99% for component A and greater than 90% for component B under the conditions described. Because of the purposely low aerosol concentration, the filtration efficiency of the high efficiency filter for the B component could not be evaluated more precisely. Previous tests with higher aerosol concentrations indicated efficiencies of greater than 99.99% and greater than 99.91% for components A and B, respectively. -7- The same filtration efficiency was noted for fiber glass filter media samples received from four high efficiency filter manufacturers. Moist Atmosphere Recent experiments have shown that moist conditions can cause samples of high efficiency filter medium from different manufacturers to be reduced in their effectiveness for trapping particulate aerosols of the type expected from the melting of vo, fuels. Under ~ 95% relative humidity at room temperature, efficiencies as low as 93% have been noted but, on the average, efficiencies of 98 to 99% have been obtained. These efficiencies are to be compared with > 99.9% under a relative humidity of < 3%. EFFECT OF MOISTURE ON AEROSOL BEHAVIOR This behavior in the presence of moisture was not anticipated and because of the implications in filter design and operation some research effort was redirected in order to define the role moisture was playing in reducing the efficiency of particulate filters. The aerosol generator was redesigned and the electrodes were housed in a heavy glass "tee". The sweep gas entered the generator hy a silica sleeve around the top electrode. Downstream from the aerosol generator, the apparatus was such that it could be changed to the requirement of each experiment, but bascially, it was arranged so as to divide the aerosol stream equally in two legs permitting two variables to be compared in each experiment by imposing different conditions of environment on each leg. Analysis of the aerosol behavior was accomplished by passing the entire air flow from each leg through a fibrous filter analyzer (FFA). The experiments to date have demonstrated that different profiles are obtained with a FFA sampling dry and wet air environments and have produced some Information to aid in deciding whether the different flitering patterns in wet -8- atmospheres are due to moisture inhibiting an aerosols' tendency to agglomerate or to moisture interferring with the filtering mechanism of the Dacron mats of the FFA. In each instance a flat distribution of particles through the FFA would result. In dry air the deposition on the Dacron mats of the FFA was quite characteristic. Greater than 90% of the sampled aerosol was retained on the first Dacron mat, an indication that agglomeration has occurred to an extent that particles of a size were produced which were easily stopped on the relatively open structure of a Dacron filter. In moist air the large accumulation of particles on the first Dacron was not generally found, but instead a more even distribution of the aerosol was found through the successive Decron layers of the pack. A physical difference has also been noted in the physical characteristics of an aerosol produced under humid conditions and under dry conditions. Electron photomicrographs of an aerosol produced under high relative humidity reveal that the particles are covered with a thin film of unknown composition and that agglomerates are in the form of chains (Fig. 10) rather than clusters as observed under dry conditions (Fig. 4). Evidently the stability and filtration characteristics of these two types of aerosols differ in some respects. To demonstrate moisture effect on the profile of a Dacron pack, an aerosol was generated in 1% relative humidity air; one stream continued under dry conditions, the other passed through a water bubbler before sampling. The deposition profiles are 1llustrated in Fig. 11. In another experiment the aerosol after passing the water bubbler was allowed to age before being sampled and, whereas in a dry environment this process would result in agglomeration, no -9- agglomeration with aging had occurred in the wet aerosol. Next, an aerosol was generatei in 80% relative humidity air, the steam divided, one-half being sampled in 80% relative humidity conditions, the other half passed through a water bubbler before sampling. Both fibrous filter analyzers gave similar flat profiles. The conclusion from these experiments was that just the presence of moisture is the governing factor and that it does not matter whether contact between the aerosol and moisture is established by bubbling through water or by mixing with forward water in the form of vapor in a high relative humidity atmosphere. The results also implied that the presence of moisture stabilized, the aerosol and inhibited agglomeration. In experiments where an aerosol was found in a dry a tmosphere, subsequent passage through a water bubbler was presumably destroying agglomerates Leurred; known by previous experience to have been found in the dry experiments. An alternative interpretation, of course, is that moisture was not affecting the physical size of the aerosol but was lowering the Dacron filtering efficiency. An attempt to resolve this question was made by generating in a wet atmosphere but sampling with a heated FFA to reduce the uptake of moisture by the Dacron fibers. In this experiment the aerosol formed in 80% relative humidity air was divided, one-half being sampled by the heated FFA, the other half, for comparison, was carried through a heated holdup vessel before sampling with a heated FFA. 1.12 this way the profile obtained by sampling a wet envirnment with a hot arullyzer was compared with that of one sampled from a dry atmosphere with a hot analyzer. The flat distribution obtained from earier experiments was not obtained and the conclusion drawn was that moisture must also reduce the efficiency of a Dacron filter; when the moisture content is reduced or eliminated by heating the analyzer, the Dacron filtering efficiency -10- increases. However,a complete comparison of the aerosol distribution through the * * • -. - . - - -- - - - -- two hot packs showed some differences. The FFA processing the wet aerosol showed a greater proportion of penetrating species on the final membrane filter of the analyzer and so tended towards a. somewhat flatter profile than the FFA on the other leg. Although moisture was shown to affect the performance of Dacron packs, it must also operate on the aerosol to a certain extent. In the niext experiment the aerosol concentration was reduced and again the difference between the two analyzers was apparent but not 8,8 pronounced. The results supported the conclusion of the previous experiment but also demonstrated thut - - . .- t- there is a concentration effect to be taken into account when considering the effect of moisture on the aerosol agglomeration mechanism. Study of this moisture effect upon aerosols of uranium oxide and stainless steel and upon the filtration of these aerosols by high efficiency filter, materials is continuing. FILTER TESTS IN THE NUCLEAR SAFETY PILOT PLANT A system has been designed and installed for the testing of high efficiency filter-charcoal bed combinations in the NSPP under accident conditions. Major components of the system include a demister, high efficiency filter, and a charcoal bed incorporated in a remotely removable canister (Fig. ll and Fig. 12), a sealed compressor for gas circulation, and three May pack samplers. The system is designed for a flow of 20 cfm of steam and gas at 300°F and 50 psig pressure. The demister design is based on the work of Peters(5), It contains a 2-in. thick style 321 SR York Demister(4) of Teflon (5) fibers (0.8 m11 diam.) woven together with stainless steel wires (6 mil dian.). Velocities through the demişter are up to 8 fps and the pressu • drop is less than 1.0 in. Ho. The -11- high efficiency filter 18 a circular Flanders style 7061R-q filter with aluminum separators and glass fiber filter media containing a binder to provide high wet strength. The pressure drop across a clean filter 18 about 1.8 in. Hgo. Two Flanders 11-in. square charcoal beds packed with Pittsburgh -12 + 30 mesh type PCB coconut-shell activated carbon are used for the final cleanup stage in the canister. To date, the loop has been operated in NSPP runs 10, 11, . 12 and 14; Runs 10 and 11 were primarily for deposition and transport studies in the containment vessel, with the filter loop operated as a secondary objective late in the runs to test the loopequipment and obtain fission-product removal data from long-aged containment atmospheres. Run 12 was made primarily to test filter loop operation under conditions prevailing soon after an accident. Run 14 utilized actual irradiated fuel specimens for fission-product release and was operated under reducing conditions. Briefly the runs have demonstrated that when fuel meltdown occurs under reducing conditions (steam and H, present) a large fraction of the iodine (~ 70%) is collected on the absolute filter. However, if fuel meltdown occurs under reducing conditions and moisture condensation is allowed to occur within the canister, then the iodine penetrates to the charcoal. Run 10 - Furnace Atmosphere Reducing (He, H2, H2O), Steam-Air Mixture in Containment Vessel Run 10 was the first run in which the filter loop was operated and was primarily a shakedown of the loop equipment and operation. The filter loop was therefore not used until very late in the run (12 h) and was operated for 8 hr. The loop was operated without a demister sincethe demisters had to be returned to the manufacturer for repacking because of a deficiency in packing density. This did not compromise the performance of the loop, since at the end of 12 hr -12- there was not appreciable moisture in the atmosphere. Because of the low initial level of activity and the rapid decrease after the start of the loop, the May pack samples taken around the filter loop were essentially background. A better index of loop effectiveness is the May pack data from inside the containment vessel. The +5+ I activity from the May pack samplers in the vessel is shown in Fig. 53. The A level (top) 1s at the same elevation as the nozzle to the filter loop; the B level (middle) is about half-way between the levels of the nozzles to an from the filter loop. The removal of activity from the vessel atmosphere was surprisingly rapid. The dashed line in Fig. 14 shows the removal that would be expected if the vessel atmosphere were completely mixed during loop operation. The more rapid removal leads to the conclusion that flow in the vessel during loop operation 18 a combination of mixed and slug flow. After the run, samples of the high efficiency filter and charcoal bed were analyzed, and a material balance was made. This showed that at the time of loop operation approximately 70% of the S-I and 100% of the 194Cs were removed by the high efficiency filter. Ruthenium-106, strontium-85, and cerium- 144, the other simulants in the run, did not show up in the filters. Considering that the loop material balance is based on spot samples from the chərcoal beds and filter and that the vessel content is based on limited sampling (two May packs locations) in the vessel, there is good agreement (within a factor of 2.2). All samples in the containment vessel were essentially background after 2 hr of loop operation and the loop was shut down after 8 hr of operation. Steam-Air Mixture in Containment Run 11 - Furnace Atmosphere Oxidizing Vessel During run 11 the filter loop was operated for two short periods, from the 12th to the 13th hour and from the 21st to the 25th hour. In this run the flow through the loop was inadvertently reversed. The flow was through the charcoal bed, then the high efficiency filter and the demister, with suction from the bottom of the containment vessel and discharge into the top. This run 18 considered to simulate the efficiency of a charcoal bed not preceded by a demister and a high efficiency filter. The calculated efficiency of the l-in. charcoal bed based on six sets of samples taken upstream and downstream of the bed ranged from greater than 98.68% to greater than 99.87%. Actual efficiencies were probably in excess of the calculated values because all the downstream sampleswere close to sample "zero" which is a significant figure. Run 12 - Furnace Atmosphere Reducing (He, H2, H20), Steam-Air Mixture in Containment Vessel The objective of run 12 was to demonstrate filter performance under steam conditions. To accomplish this the filter loop was started 2 hr after the start of the run while the vessel was at 98°C and 21.5 psig. Very adverse conditions on the high efficiency and charcoal filters (maximum entrainment) were imposed by not heating the filter canister. The loop was operated continuously for 6 hr. There were 0.92 liters of dark-colored condensate found in the canister upstream of the high efficiency filter and 1.8 liters of clear condensate found downstream of the high efficiency filter. There appeared to be no damage to the high efficiency filter due to the condensing steam conditions. -14- The condensing steam conditions did interfere with the operation of the May pack samplers and no sat:18factory sampling data were obtained. Therefore, the total amount of radioactivity in the filter, charcoal, and condensate was determined. Of the +5*C8 entering the loop canister, 0.7% was found on the demister, and 98.5% on the high efficiency filter; and 0.8% of the 0.92 liters of condensate between the demister and the filter; none was found in the charcoal. of the +11 entering the loop canister none was found on the demister or high efficiency filter; 7.3% was found in the 0.92 liters of condensate between the demister and the filter, 9.7% was found in the 1.8 liters of condensate between the filter and the charcoal filter, and 83.0% was found in the charcoal filter. Run 14 - Furnace Atmosphere Reducing (He, H2, 120), Steam-Air Mixture in Containment Vessel This was the first of the NSPP runs with actual f18sion products from irradiated fuel specimens. Analytical results are not yet available from the samplers of the filter loop system. IV. COMMENTS The effect of moisture on filtration efficiency has beca demonstrated only in the laboratory thus far in this study. The low level of particulate radio- activity and the resultant loss of analytical sampling efficiency preclude such observations in the NSPP experiments. Primarily these NSPP experiments have been made to observe iodine behavior in a filter loop system. Other means will be sought to permit the study of the behavior of particulate aerosols to be performed on a somewhat larger scale. -15- 1. 2. REFERENCES M. D. Silverman and W. E. Browning, Jr., Science 143, 572 (1964), F. Dyer, J. F. Energy, and G. W. Leddicotte, "A Comparative Study of the Neutron Activation Analysis of Uranium by Delayed-Neutron Counting," ORNL-3342 (1962). A H. Peters, "Application of Moisture Separators and Particulate Filters in Reactor Containment, " DP-812 (December 1962). Registered trademark, O. H. York Company, Inc. 3. 4. 5. Registered trademark, E. I. duPont de Nemours and Company, Inc. -16- FIGURE CAPTIONS Aerosol Generator Which Simulates a Reactor Accident by Arc-Heating Electrodes of Uranium Oxide and Stainless Steel Packed with voz. Components in Typical Dacron Fibrous-Filter Analyzer; Complete Assembly Contains Ten Dacron Fliters in Teflon Sleeve. 3. Distribution of Mixed Uoz and Stainless Steel Aerosol Within Fibrous-Filter .. R - - - - 4. - . . . . Analyzer. Arc-Source Aerosol from Electrodes of vo, and Stainless Steel-Clad to, in Helium Atmosphere; Particle Size, 0.012 to 0.075 m; Median Size, 0.018m. (Magnification 132,000x). Particle Size Distribution of a 102-Stainless Steel Aerosol. Response of a Fibrous Filter Analyzer to +57Cs in an Aerosol from In-Pile Melting of voz: Experimental Setup for Generation and Filtration of Simulant Arc-Source Aerosols. 8. Determination of Filter Efficiency - Response of Fibrous Filter Analyzer Preceded and not Preceded by a High-Efficiency Filter. Determination of Filter Efficiency at Lower Concentration - Response of Fibrous Filter Analyzers Preceded and not Preceded by a High-Efficiency : - 9. - - - - - . - . . . Filter. - - - - - - 10. Appearance of Aerosol Formed in a High Humidity Atmosphere; note thin film covering the particles (Magnification 165,000x). ll. Response of Fibrous Filter Analyzer to Identical Aerosol Under Wet and Dry Conditions. 12. Schematic Flow Diagram for NSPP Filter Tests. 13. Filter Canister for NSPP Filter Tests. 14. Behavior of 15I Activity in NSPP Containment Vessel - Run 10. - -- - MOTO 6789 w UO, ELECTRODE STAINLESS STEEL CL AODING VO2 FUEL die Fig. 1. Aerosol Generator which Simulates a Reactor Accident by Arc-Heating Electrodes of Uranium Oxide and Stainless Steel Packed with voc. - - ORNL-DWG 65-8013 STAINLESS STEEL SPACER ABSOLUTE FILTER (IF USED; ---- STAINLESS STEEL SCREEN STAINLESS STEEL SPACER DACRON FILTER TEFLON SLEEVE AIR FLOW W Fig. 2. Components in Typical Dacron Fibrous-Filter Analyzer; Complete Asserably contains Ten Dacron Filters in Teflon Sleeve. ORNL-OWO 66 - 8014 HELIUM SWEEP: 500 cc/min . .: 235U OR STAINLESS STEEL ON DACRON FILTER (g! TYPE 304 STAINLESS STEEL . 235 U 10-8 .. 1 2 3 8 9 10 4 5 6 7 DACRON FILTER NUMBER Fig. 3. Distribution of Mixed Uo, and Stainless Steel Aerosol Within Fibrous- Filter Analyzer. " M + *.** . . - wwe -o .. ...... ...-- . ... . ..... . .. ... . ..:.:. .. --- -- H..:.. · - - ---- = PARTICLE SIZE, microns . .. ,•1. .".0; 1000 i .::" . Fig. 4. Arc-Source Aerosol from Electrodes of vo, and Stainless Steel-Clad vo, in Helium Atmosphere; Particle Size, 0.012 to 0.075 m; Median Size, 0.018 4. (Magnification 132,000x). . . ..- in.:73-77under :-- orisn . • • :. . ... .. .. .. . :.: :::.:. ... . Z .:- · .... :: ::........::* ?* :-:- ::: ...-:. .. , ...imami ..? ;!; 66 66 ao .-7.* . :* 1 ?%.. ." ... hacer . .. 99.95 99.9 99.8 outcasino a wid.coothies in this is in. di 99.7. 99.5 Solid Een milli man that conditie liet . . Words omet.- to be . . ; PARTICLES OF SIZE LESS THAN'THAT INDICATED, -% Fig. 5. Particle Size Distribution of 'a vog-Stainless Steel Aerosól. Subotom hidtimes the hearts and (99/"VI OISIA JN) 196-X ... 2° 0 tables dedica a thanks the wild 05 0. 0.01 .. .03 .025 .02 .048 .046 DIO 2100 .010 600 800 .007 .006 .005 000* e rna 7 .' !' O PARTICLE SIZE, microns . - - . -. - •.-.. --- - Fig. 6. Response of a Fibrous Filter Analyzer to *Cs in an Aerosol from In-Pile Melting of vog. Pro v1.) . . when coda ali.misal .. FILTER PACKS ABSOLUTE FILTER ARC-POWERsning RED AEROSOL GEHEF::.: rinnarai marresh Fig. Fx Experimental Setup for Generofion ond Filtration of Simulons Arc Sourco Aerosols. ORAL-OWO 65.1314 TT 1 um. : r O NO ABSOLUTE FILTER • ABSOLUTE FILTER PRECEDING DACRON FILTER AIR FLOW: 1400 cm3/min .......;" 1003 .. GRAMS OF 2350 ON DACRON :ILTER A TO 1009 10.10LL 9 2 9 3 4 5 6 7 8 DACRON FILTER NUMBER Fig. 8. Determination of Filter Efficiency - Response of Fibrous Filter Analyzer Preceded and not Preceded by a High-Efficiency Filter. ORNL - Owo 65 - 6015 O NO ABSOLUTE FILTER PRECEDING DACRON FILTER PACK ACSOLUTE FILTER PRECEDING DACRON FILTER PACK . AIR FLOW: 930 cc/min . . . . . . . . ... COMPONENT A .. 235, ON EACH DACRON FILTER (9) COMPONENT 8 . .. ... . . 1 2 3 4 5 6 © DACRON FILTER NUMBER 8 9 10 Fig. 9. Determination of Filter Efficiency at Lower Concentration - Response of Fibrous Filter Analyzers Preceded and not Preceded by a High-Efficiency Filter. i w bio Tome . Fig. 10. Appearance of Aerosol Formed in a High Hunidity Atmosphere; note thin film covering the particles (Magnification 165,000x). i . . ...... .. :. :.:.:.:.. *.: .:. ::... ........... ..... ... ........ ........ .. . : i '. "* • -. - • • . . . :.. ... : -... لللنلنناننلالالالا :.: httie MTHITTIMAN T TTTT ::!HINUHUN 1:::::..14!!!LUD II. biililolill !!:1:ill . :i: !!!!!!TIITIN MITIHITI 1 . .. .... : dari Oi!ii! ilipood i : 1 PRIS 1. RE " ni WINTIMURIT MUHITIMI !! liilillllllllllIIlId. NWUUT litullil!! !!! !!BILIULUI WHIT i WIN :- Mini PAMU:1 1 milli 1: !!!! ! :: !!!! : WWWUWULUI wkollu ..: C . * MlllllllNIM lelonil TITTA mpwUUTUU. Ī PHHHWIUDILO WWW l. !- : HBACKUPTILTE HOU KAN ::III QULL pinili lullll|TTTI UNIT. DANOIDUDINI 114.lit : HlllllU Di v innuligM 10. min MUNWIN Hill Humil 1::::llulil ALKA ;::.. V i. !!!;gono .).. !:!18!! . . : . : : : : ::Will TUNUT HUNNIUI 1000WII U :. oliniul TOUTUMIillll BARONI WINNI KUULU UTTITUDUNDI :1: TH DOMIIN.wmonITIN DMINIBIDIIN IllIINNI Wanili Wii DIII HD turbiumMU Mit HHHumn MMR WilliamHIWUTLU •11:11!!1 .! !!";.! . . . SERBIA IBRO .: 1 BROK ! Innmu SMITHDIHIIIII 100MM ndani ... Inna... HOM111111 .: . LMHTOIT: minihin DODHI HUNII CRIA NIUA N TI CAMPWONDU DURITOETmniniu MIL Llull::: WAIULIUDI M inderhuillilm DEHRADU HUL E:BEEEE 1 BREED Wii ,#!HAI .:T, 1:10 RPM Vinil L !!!iiul ATARINNAR BH MILLI DICUNT onim i t . . ! HULIHIII weil wuwuwi. MORIB MNIM Ririman BERID il DA . .0. 3:1 tayyorgar! is a . This on!!!: TINTE in :.81.:.it: :11 HIHI WIND ONUNUI, 7:12 :1:1:1EEEEEE 13 till! IKHT:1:: ni . 8. ll. Response of Florous' Filter Analyzer to identical Aerosol Under Wet and Dri randitions 1 . WIHHUMI Unit TOT) MillUWT mnininha Hnumin ETUIENIS MINIMU!!, Hihihiilid B inntil 100 UTTI MATHILTONIOMISINI B: DWUOINTII LAIMIILI HALLIT millj MORulli. H. DACRON LAYER. NOMRON 1 F V nmann 111!! ! WHOH PREDAMINI KALORInANDI HARD Damamull ULTRAPANI HIM MUH. 17 WHILSW1l ننناننن II .11111 VER HDHIHI 400 ml 2012! :1:: . 69EEEEEEEEEEEEEEEEEEEEEEEE ... : DDD MIHHAILOlulu Bohumllll und OLUR!!!IUNUL iiiiii 1 Mandi goml;1:... in l.1..6 ,... HIBURT till HI MWINNI HORIHANNINI ETHNINIIMIINI AMHIIIIHIN HHuml WIDTWI Hin; 1.1.1 NIMIT ... AWI ANIMLJANI WHIHIHIRAN.willal H illon Liliw Will W h o 'll t:1:1:1:1 HIP dildi LOORHITE ARABU THUN DUMMUTIH QRAMIIIMIIIIIHIIHD HULLWIDT ili . .. 1 BUMNIUM HINTIMMHILI OMIHODMOINONIUMINIUM wilkuthILMHINJINI OH WALDWIlllllllll wwwili Walllllll UNIWI Will Anlllll - WIL t 1 1111111 TRIIIIII l lii ET DORMIOIIIII... . Plan Ini OPT:V12 LOTUTT MUUD H ullum WINKL . MOIlllllMHII INT: Mihil UKRI HAMDULI H OMINIIW KUWWER er h ill W ! IT Liliki SRBIA WW:Hill 1 :10 SEBB Will: HIHNINI DIMINT WWMUURIITTI Ultime ; ;:. .Colletwage?? !!! My now for more negarçon of $ l.n.; ! i. in. ...".. .. . ADEIRA WHIMUM Sum olum II HUIMMUUT RHOD11907m0UMINT 1:1010010...Donmhuinn BIllIIlIIT RHUMUNUDI 1:41.ili Illu - + 11 ill ..:: W W !!! 1 KIWI WNBMUI OOONOD ♡ Till TAU!! IIIIRI LIMIT Billig wil nilliil !T17:15 Til I II TIMMTUDITII @uno ºn THUM: O vwO. Ludmill I.!. A o N Radioactivity (counts/min.) AOC IN U. 1.A EUGENE OIETZGEN CO. 5 CYCLES X 12 O!VISIONS PER INCH SEMI-LOGARITHMIC ,. NO. 340.1512 DICTZGEN GRAPH PAPER . . .. ... .... : . .:ico .... .... . . ....... .... .. - •• - -- ---- ..... . . . ........ . - . .. ORNL-OWO 65-1315 SEQUENCE VALVE 6-ELEMENT SAMPLER 6-ELEMENT SAMPLER SAMPLER TO VACUUM ABSOLUTE FILTER CHARCOAL FILTER DEMISTER FILTER CANISTER :. MODEL CONTAINMENT VESSEL COMPRESSOR .... .... ........ : : Fig. 12. Schematic Flow Diagram for NSPP Filter Tests. :::....:: : :: OANL-OWO 65.1646 SAMPLE BAFFLE SAMPLE Rogeaaaa .999 29.0990090.co. costa Q90922., So 20-cim FLOW - - .. . - .* i * : 22 STEAM TRACE : ಓಂರಿರಿರಿಲಕಕರರರರರರರರರರರರರರರರರರರರರರರರರೆ 12 a la alin. CHARCOAL FILTER - 1 ABSOLUTE FILTER DEMISTER Fig. 13. Filter Canister for NSPP Fllter Tests. ORNL-DWG 66-585 10,000 RECYCLE FILTER KOOP OPERATING BII ACTIVITY IN CONTAINMENT VESSEL (dis/min.liter) 1 REMOVAL WITH PERFECT MIXING A A-LEVEL MAY-PACK DATA • B-LEVEL MAY-PACK DATA K DATA 100 200 300 400 500 TIME (min) 600 700 800 900 - - - - * - - Fig. 14. Behavior of SI Activity in NSPP Containment Vessel - Run 10. . - :* * - * - - - - - - - * - . 1.1. MAN HA T " END DATE FILMED 10/21 / 66 sta .. All . . CUMA! INT " N