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Confinement of airborne radioactivity. Progress report, January--December 1974

Description: Several commercial activated carbons, marketed for iodine removal in reactor off-gas cleanup systems, were evaluated for iodine penetration at elevated temperatures (4 hr at 180$sup 0$C), and the penetration data varied widely. Subsequent chemical analysis of the samples indicated a strong correlation between the atom ratio of iodine to potassium (I/K) in the carbon and the high-temperature performance data. Iodine penetration tests were also performed on several carbons in an intense gamma radiation field (greater than 10$sup 7$ rads/hr). Test data show that carbons intentionally exposed to high concentrations of DOP aerosol performed as well as unexposed carbons. Studies of the rate of evaporation of elemental iodine from aqueous solutions indicated that significant quantities of I$sub 2$ might be expected to become airborne within a short period of time (5 hr) after release to open ponds. Addition of sodium thiosulfate to the solution substantially reduced the evaporative loss of iodine; however, the effects of high-intensity radiation fields on iodine-thiosulfate solutions remain to be evaluated. Small HEPA filters containing filter media of the type used in the Savannah River confinement system were exposed to reactor building air and a high-intensity radiation field. Following this exposure, they were tested for flow performance under simulated accident conditions. Radiation exposure slightly impaired the performance of new filters and improved the performance of service-aged filters. Service aging effects on filter performance were far more significant than radiation effects. (auth)
Date: January 1, 1974
Creator: Dexter, A.H.; Evans, A.G. & Jones, L.R.
Partner: UNT Libraries Government Documents Department

Confinement of airborne radioactivity. Progress report: January--December 1975

Description: Efforts are underway at Savannah River Laboratory (SRL) and the Naval Research Laboratory (NRL) to develop new carbon-impregnant formulations suitable for use in nuclear power plants as well as in the SRP system. Emphasis has been placed on carbons derived from domestic raw materials and impregnated with an amine having lower vapor pressure, higher flash point, and lower cost than triethylenediamine (TEDA). Promising results have been obtained with carbons derived from coal, petroleum, wood, and coconut and impregnated with a combination of iodine salts and hexamethylenetetramine (HMTA). Service-aging of several of the HMTA-iodine salt carbons is also being studied. A separate study of the ability of sodium thiosulfate and potassium hydroxide to retain iodine in aqueous solutions in the presence of high-intensity gamma radiation show that concentrations of approximately 1 wt percent thiosulfate are required to reduce iodine evolution to less than 1 percent. A 0.05 wt percent addition of potassium hydroxide has about the same effect. These studies revealed that lower concentrations of thiosulfate actually appear to promote evolution of both iodine and an unidentified species of iodine that is capable of penetrating several inches of carbon adsorber. The unidentified iodine compounds are, however, efficiently retained by a HEPA filter. This result suggests that the penetrating iodine may exist in the form of a particulate or aerosol.
Date: January 1, 1975
Creator: Evans, A. G. & Dexter, A. H.
Partner: UNT Libraries Government Documents Department

Ventilation systems analysis during tornado conditions. Progress report, January--June 1975

Description: The principal concern of this investigation is to develop the capability to simulate the dynamic effects of a tornado depressurization on a ventilation system. The basic formulation and solution of the two-zone series model ventilation subsystem is based on lumped parameter component response equations, the isothermal compression of air, and the conservation of mass. Solutions based on these assumptions are also presented for the two-zone series model with natural bypass, the two-zone series model with recirculation, and the natural branching model. A parameter study is presented comparing the effects of changes in system resistance, system capacitance, and variable tornado depressurization rates. The adaptability of the basic formulation to adiabatic compression of air and the addition of duct resistance is examined. A quasi-steady formulation is introduced and preliminary considerations of the importance of inertia are presented. Preliminary conclusions in this area indicate that inertial effects can be neglected. For relatively long ducts slow shock development appears possible. Work on the effect of tornado depressurization rates as related to shock development and on the importance of inertia effects is continuing. (auth)
Date: November 1, 1975
Creator: Bennett, G.A.; Gregory, W.S. & Smith, P.R.
Partner: UNT Libraries Government Documents Department

Confinement of airborne radioactivity. Progress report: January--December 1976

Description: Service aging studies conducted at the Savannah River Laboratory (SRL) show that Type GX-176 carbon has a useful life of at least 30 months as a halogen absorbent in the airborne-activity confinement system for the Savannah River production reactors. The studies also show that elemental iodine retention by this carbon at high temperature (180/sup 0/C) is more a function of the pH of the service-aged carbon than of the length of time in service. Type GX-176 carbon is a 10 x 16 mesh coconut shell charcoal impregnated with potassium iodide and trietyhylenediamine. Studies of new absorbent formulations at SRL show that coal-, coconut-, and wood-base carbons can be impregnated with hexamethylenetetramine (HMTA) and combinations of iodine, iodine salts, potassium hydroxide, and phosphate salts to obtain methyl iodide penetration values of less than 1%. Consistent penetration values of less than 0.5% have been obtained with two coal-base carbons when the total iodine and HMTA were added at the 2% level. Three phosphate salts (NaH/sub 2/PO/sub 4/.H/sub 2/O, Na/sub 2/HPO/sub 4/.7H/sub 2/O, and Na/sub 3/PO/sub 4/.12 H/sub 2/O) have been used successfully as pH buffers and ignition retardants. Boric acid was found to be an unsatisfactory ignition retardant.
Date: January 1, 1976
Creator: Evans, A. G.
Partner: UNT Libraries Government Documents Department

Effects of explosion-generated shock waves in ducts

Description: An explosion in a space causes an increase in temperature and pressure. To quantify the challenge that will be presented to essential components in a ventilation system, it is necessary to analyze the dynamics of a shock wave generated by an explosion, with attention directed to the propagation of such a wave in a duct. Using the equations of unsteady flow and shock tube theory, a theoretical model has been formulated to provide flow properties behind moving shock waves that have interacted with various changes in duct geometry. Empirical equations have been derived to calculate air pressure, temperature, Mach number, and velocity in a duct following an explosion.
Date: January 1, 1976
Creator: Busby, M. R.; Kahn, J. E. & Belk, J. P.
Partner: UNT Libraries Government Documents Department

Inhomogeneous electric field air cleaner

Description: For applications requiring the filtration of air contaminated with enriched uranium, plutonium or other transuranium compounds, it appears desirable to collect the material in a fashion more amenable to recovery than is now practical when material is collected on HEPA filters. In some instances, it may also be desirable to use an air cleaner of this type to substantially reduce the loading to which HEPA filters are subjected. A theoretical evaluation of such an air cleaner considers the interaction between an electrically neutral particle, dielectric or conducting, with an inhomogeneous electric field. An expression is derived for the force exerted on a particle in an electrode configuration of two concentric cylinders. Equations of motion are obtained for a particle suspended in a laminar flow of air passing through this geometry. An electrical quadrupole geometry is also examined and shown to be inferior to the cylindrical one. The results of two separate configurations of the single cell prototypes of the proposed air cleaner are described. These tests were designed to evaluate collection efficiencies using mono-disperse polystyrene latex and polydisperse NaCl aerosols. The advantages and problems of such systems in terms of a large scale air cleaning facility will be discussed.
Date: January 1, 1976
Creator: Schuster, B. G.
Partner: UNT Libraries Government Documents Department

Nuclear air cleaning handbook. Design, construction, and testing of high-efficiency air cleaning systems for nuclear application

Description: The handbook is a revision of ORNL/NSIC-65. The purposes of the handbook are to summarize available information in a manner that is useful to the designer, to point out shortcomings in design and construction practice, and to provide guides and recommendations for the design of future systems. (TFD)
Date: January 1, 1976
Creator: Burchsted, C. A.; Kahn, J. E. & Fuller, A. B.
Partner: UNT Libraries Government Documents Department

Penetration of HEPA filters by alpha recoil aerosols

Description: Tests at Oak Ridge National Laboratory confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter medium, identical to that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.97 percent quoted for ordinary particulate matter have been observed with /sup 212/Pb, /sup 253/Es, and /sup 238/Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers, by the alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow. Dependence on the air flow velocity is slight. It appears that this phenomenon has not been observed in previous experiments with alpha-active aerosols because the tests did not continue for a sufficiently long time. A theoretical model of the process has been developed, amenable to computer handling, that should allow calculation of the rate constants associated with the transfer through and release of radioactive material from a filter system by this process.
Date: January 1, 1976
Creator: McDowell, W. J.; Seeley, F. G. & Ryan, M. T.
Partner: UNT Libraries Government Documents Department

Pressure transients across HEPA filters

Description: Knowledge of HEPA filter effectiveness under various pressure transients is critical to maintaining and assuring nuclear plant safety. The facility now being constructed at New Mexico State University has been designed to provide information that can be used to predict the response of HEPA filters when subjected to various pressure transients.
Date: January 1, 1976
Creator: Gregory, W. S.; Smith, P. R.; Ricketts, C. & Reynolds, G.
Partner: UNT Libraries Government Documents Department

Tornado depressurization and air cleaning systems

Description: Results from analytical and experimental investigations of tornado depressurization effects on air cleaning systems are presented. Development and use of a computer code that simulates the internal pressures and flows within an arbitrary ventilation system is described. The formulation of fluid motion equations is based upon lumped component response, isothermal or adiabatic compression of air, and conservation of mass. A computer generated movie is shown illustrating the flows and pressures in a simple system. Also described are experimental investigations to determine air cleaning component response to high flow rates caused by tornado depressurization. HEPA filter is the principal component under investigation. A description of the experimental apparatus is given and preliminary test results presented.
Date: January 1, 1976
Creator: Gregory, W. S.; Duerre, K. H.; Smith, P. R. & Andrae, R. W.
Partner: UNT Libraries Government Documents Department

Use of a single particle intra-cavity laser particle spectrometer for measurements of HEPA filters and filter systems

Description: Current tests of HEPA filters and/or filter installations using DOP aerosols and conventional forward light-scatter photometers are limited to measuring protection factors of 10/sup 4/ to 10/sup 5/. In addition, forward light-scattering photometers have markedly decreased sensitivity to less than 0.3 ..mu..m particles and basically measure only a scattering signal which is not uniquely related to any given concentration or size distribution of scatterers. These limitations require that high efficiency systems, such as multiple stage HEPA filters, be evaluated one stage at a time, a procedure which is quite often impractical for many existing air cleaning systems and which may be in error. In order to obviate these difficulties, a single particle intracavity laser particle spectrometer has been used to measure protection factors of up to 2.4 x 10/sup 8/ for multiple HEPA systems and individual double ply HEPA filters. Because of the instrumental size resolution, protection factor as a function of particle size can be determined from .06 ..mu..m to 2.9 ..mu..m. The lack of background enables single counts to be statistically significant. Since coincidence errors occur at particle concentration greater than 10/sup 6//liter, a known dilution must be introduced to measure challenge concentrations greater than this. The dilution measurement may be accomplished with the aid of a forward light-scattering photometer.
Date: January 1, 1976
Creator: Schuster, B. G. & Osetek, D. J.
Partner: UNT Libraries Government Documents Department

Ventilation systems analysis during tornado conditions. Progress report, July--December 1975. [Depressurization effects]

Description: A review of some existing digital simulations of fluid systems, a brief description of the proposed generalized computer code, a description of, and results from, two solution techniques, and a sample test case ventilation system are presented. The review of some fluid system simulations covers methods and techniques for development of a more general digital solution technique than the successive substitution method used in previous analyses. The structure and organization of the computer code under development is discussed. A section dealing with the development of a user-oriented input to the code is also presented. Two solution techniques suitable for solving the simultaneous nonlinear algebraic and differential equations are presented. One of the techniques is based upon a loop method and employs Newton's method for obtaining simultaneous iterative corrections for the solution. The second approach is based upon a node orientation and employs Cross' method to arrive at successive iterative corrections for the solution. Graphical results using both methods are presented. The results are essentially identical. A ''test-case'' ventilation system is introduced. The test-case ventilation system model was developed primarily for ''debugging'' the proposed generalized code. The test case is a simple yet realistic representation of the types of subsystems which could be encountered in nuclear facilities.
Date: April 1, 1976
Creator: Gregory, W. S.; Duerre, K. H. & Bennett, G. A.
Partner: UNT Libraries Government Documents Department

Direct in-vessel applications experiments at Harvard Air Cleaning Laboratory. Progress report, January 1, 1976--March 31, 1976. [Removal of LMFBR sodium fire aerosols]

Description: Experimental research on emergency direct in-vessel air cleaning systems for the LMFBR is described. Results which characterize the aerosol from 1 lb sodium pool fires made in a 90 m/sup 3/ chamber are presented. The effective use of turbulent agglomeration to enhance aerosol sedimentation is described. The composition of the aerosol as determined by atomic absorption and chemical tests is discussed. Results from small scale sodium aerosol scavenging tests are presented, anticipating large-scale powder dispersal tests to be conducted in the chamber. Plans for testing the sonic agglomeration characteristics of sodium aerosols are discussed.
Date: May 1, 1976
Creator: Mallove, E. F. & First, M. W.
Partner: UNT Libraries Government Documents Department

Direct in-vessel applications experiments at Harvard Air Cleaning Laboratory. Progress report, April 1, 1976--June 30, 1976. [Removal of LMFBR sodium fire aerosols]

Description: The goal of direct application in-vessel air cleaning systems is to reduce the two hour integrated dose leaking from a containment vessel after a design basis accident by rapidly reducing airborne sodium aerosol concentration within the vessel. This reduction in concentration is achieved by direct action on the entire containment volume rather than by a more conventional recirculating clean-up loop. Strategies that have been evaluated include: increased sedimentation by enhanced agglomeration using powder dispersal, acoustic energy, or turbulence, and powder scavenging. Experiments were conducted by burning metallic sodium in a 90 m/sup 3/ chamber to achieve aerosol concentrations up to 10 gm/m/sup 3/. The time decay of the airborne mass was measured by sequential filter sampling and the effectiveness of each enhancement method was evaluated by comparison with decay profiles of untreated aerosols. Experiments with induced turbulent agglomeration show 2-hour dose reduction factors (DRF's) up to 43. Under the same scale turbulence conditions it is likely that a similar DRF would be achieved in a 30 m high containment vessel. Powder dispersal scavenging tests in the same chamber showed 2-hour DRF's up to 7.2--a performance level which would also be duplicated in a 30 m high containment vessel.
Date: July 1, 1976
Creator: Mallove, E. F.; Hinds, W. C. & First, M. W.
Partner: UNT Libraries Government Documents Department

Particulate and iodine removal analysis for HTGR containments

Description: The removal of aerosol particles and iodine in the containment vessel of an HTGR following a loss-of-coolant accident was examined for two hypothetical accidents; the Design Basis Depressurization Accident (DBDA) and the Maximum Hypothetical Fission Product Release (MHFPR). Current containment cleanup system designs and others were evaluated. The HAARM-2 computer model was adapted to describe aerosol behavior and to predict the consequences of the postulated accidents and to predict the time dependent behavior (agglomeration, growth, deposition, and leakage) of the aerosol. Comparative hypothetical cases for the DBDA and MHFPR demonstrated the effect of concentration, filter removal, particle size distribution and temperature, and pressure on particle removal with the concentration level and filter removal mechanisms showing the most significant effect. For the reference containment system design, plateout on surfaces and the recirculating filter-absorber were the principal iodine removal mechanisms of those considered. Removal of airborne iodine from the containment vessel due to an air cleaning system and by surface deposition was modelled, and the time variation for the total iodine concentration in the reference plant was predicted. Surface deposition and operation of the air cleaning system rapidly lowers the airborne iodine concentration until about 0.3 percent of that released remains airborne. Beyond this point the model predicts a leveling in concentration due to desorption from surfaces.
Date: July 1, 1976
Creator: Gieseke, J. A.; Schmidt, E. W.; Baybutt, P.; Jordan, H. & Postma, A. K.
Partner: UNT Libraries Government Documents Department

Containment and recovery system for fuel-reprocessing plants

Description: Tritium containment and removal problems in a fuel-reprocessing plant are identified and conceptual process designs for reducing emissions to the environment to below 1 Ci/day are studied. The conceptual design recommended would allow an air atmosphere in the reprocessing-plant hall and would use a continuous-catalytic-oxidizer/molecular-sieve-adsorber cleanup system to maintain a 40-..mu..Ci/m/sup 3/ tritium level (5 ..mu..Ci/m/sup 3/ HTO) against 180 Ci/day leakage from components and process piping.
Date: August 25, 1976
Creator: Galloway, T. R.
Partner: UNT Libraries Government Documents Department

Evaluation of air cleaning system concepts for emergency use in LMFBR plants

Description: Nineteen different air cleaning concepts are arranged into twenty-four systems and evaluated for use as accident mitigating systems in LMFBR plants. Both single, low-leakage containment plants and once-through operation applicable to containment/confinement plants are considered. Plant characteristics affecting air cleaning requirements are defined for 1000 MW(e) plants and a sodium and radiological release term is postulated. The accident conditions under which the emergency air cleaning system (EACS) must function is established by use of SOFIRE-II and HAA-3B computer codes. Criteria are developed for evaluating the various systems and for assigning comparative ratings. The numerical ratings are combined with information on cost and development potential to arrive at recommendations for the most promising systems. The conclusion is made that reliable and effective systems are feasible for use as engineered safety features for LMFBR plants, but that development effort is required for all the air cleaning concepts evaluated.
Date: December 1, 1976
Creator: Hilliard, R. K.; McCormack, J. D. & Postma, A. K.
Partner: UNT Libraries Government Documents Department

Direct in-vessel applications experiments at Harvard Air Cleaning Laboratory. Annual report, October 1, 1975--January 31, 1977. [Removal of LMFBR sodium fire aerosols]

Description: Prototypes of direct in-vessel emergency air cleaning systems were evaluated for possible application in an LMFBR containment vessel after a hypothetical core disruptive accident. These were turbulence enhanced sedimentation, powder dispersal scavenging, acoustic agglomeration enhanced sedimentation, and combinations of turbulence with powder dispersal. The effect of turbulent agglomeration in enhancing the sedimentation of a sodum pool fire aerosol was experimentally demonstrated in a 90 m/sup 3/ test chamber, 4 meters high. Two hour dose reduction factors (DRF(2 hr)) from 7 to 56 were achieved in the 4 meter high chamber using fan-induced turbulent agglomeration on aerosols that varied in initial mass concentration from 1 to 12 gm/m/sup 3/. In the same chamber, a prototype limestone powder dispersal scavenging system was tested and achieved DRF(2 hr)'s up to 10. The beneficial effect of combining turbulence with powder dispersal in a single system was demonstrated in a test which yielded a DRF(2 hr) of 20. This was greater than for either mechanism separately applied when initial aerosol mass concentration was 2 gm/m3. Acoustic agglomeration of sodium pool fire aerosols was tested in a smaller 0.65 m/sup 3/, 75 cm high settling chamber, using an electronic siren which produced a sound pressure level of 145 dB in the reverberant chamber. The DRF(2 hr) in the small chamber with the siren operating was found to be from 17 to 31, 2 to 3 times greater than the DRF(2 hr) for unperturbed settling. Pulse-jet engines were found to be unsuitable for generating high sound levels for this application. Scaling each of the systems tested to a 30 m high containment vessel indicated no reason why one or more of the systems investigated could not be applied successfully as an emergency air cleaning system.
Date: February 1, 1977
Creator: Mallove, E.; Hinds, W. & First, M. W.
Partner: UNT Libraries Government Documents Department

Acoustic and turbulent agglomeration of sodium aerosols. Quarterly report, January 1, 1977--March 31, 1977

Description: Tests of turbulent and acoustic agglomeration of captive sodium fire aerosols at concentrations of 0.1 to 20 gm/m/sup 3/ were conducted in 90 m/sup 3/ and 0.65 m/sup 3/ vessels to evaluate these mechanisms for direct application air cleaning systems. Aerosol mass concentration decay with time was monitored by sequential filter samples. Turbulence was generated mechanically with a 51 cm diameter centrifugal fan impeller and a reverberant acoustic field was created with an electronic siren. The effectiveness of each method over a range of particle concentrations and power densities was evaluated by an agglomeration index, a measurement of particle growth based on sedimentation characteristics. Both turbulent and acoustic treatment markedly enhanced sedimentation rate compared to undisturbed settling. The effectiveness of both methods increased with increasing aerosol mass concentration and increasing power input per unit volume of aerosol. The agglomeration index reached 20 for turbulent agglomeration at an aerosol mass concentration of 3 gm/m/sup 3/ and 7 for acoustic agglomeration at 14 gm/m/sup 3/ when using an acoustic intensity of 145 dB. Turbulent agglomeration was more effective than acoustic agglomeration for the same mass concentration and power density conditions.
Date: April 1, 1977
Creator: Hinds, W.; Mallove, E. F. & First, M. W.
Partner: UNT Libraries Government Documents Department