[en] This report documents the construction of a 0.914-m (36-in.)-dia. shock tube on the New Mexico State University caompus. Highly variable low-grade explosions can be simulated with the shock tube. We plan to investigate the response of nuclear facility ventilation system components to low-grade explosions. Components of particular interest are high-capacity, high efficiency paticulate air (HEPA) filters. Shock tube construction details, operating principles, firing sequence, and preliminary results are reported

[en] Problems associated with the removal of dust in working environments include the access of air to a suction plant, the ducting to a central pumping unit, filtering out of toxic constituents and the discharge to the atmosphere. With large installations, sound proofing, heat emission and cost effectiveness are additional factors. In the course of time, filters become clogged which reduces their effectiveness and increases the power requirements. A pressure manometer method is illustrated which enables an electrical contact to be activated to signal when filters need cleaning. For effective suction, the pipe entry must be as near as possible to the source of the dust. Some concentration and flow direction isometric patterns are illustrated to show the effect of distance on suction effects. (G.C.)

[en] Process for changing the filters of ventilation systems in a radioactive substances processing plant, by means of an ensemble comprising (a) a filtration chamber with an opening that can be closed by a first removable cover, (b) a box with an opening and a second removable cover, (c) a device for overlapping the first and second cover, (d) a device placed in the box for holding the overlapping covers when removed from the corresponding openings and (e) a mobile stand, in the box moving from a first position in which it can house a filter from the filtration chamber and transferred to the case, to a second position in which the overlapping covers can be placed back over the openings when a filter is in position

[en] The aim of the present work is to investigate the capability of a Wire-to-Square Tube Electrostatic Precipitator (or WST-ESP) to collect submicron particles using a Dielectric Barrier Discharge (DBD). A parametric study is carried out to evaluate the effects of four control variables that might affect the collection efficiency of the WST-ESP: diameter of the corona wire electrode, width of the ground electrode and the area of the tube section. The experimental data show that the wire diameter has a negligible effect on the WST-ESP collection characteristics. However, better overall performances can be obtained by putting in parallel several WST-ESPs with reduced section. The extension of the ground electrode and its discretization increase the collection efficiency.

[en] As the parameters of expressing the severity of back discharge, the degraded value of the field intensity, E, and the positive and negative ionic current densities, J+ and J-, are proposed, based on the charging and charge-neutralization processes in the bi-ionized field. Then, a bipolar current probe for measuring J+ and J- is described with its probe theory and some of the measuring results. Finally, the experimental verifications of the relationships holding between the charge and performance degradation factors and the probe-measured values of J+ and J- are presented. Although the laboratory results cannot immediately be extended to the practical plants, the bipolar current probe seems to provide one of the useful means for diagnosis of back discharge severity. (orig.)

[en] The charging of 10-nm-class nanoparticles in an electrostatic precipitator (ESP) according to particle charging ratio has been investigated and compared to the diffusion effect of the nanoparticles. The competition between the charging probability and the diffusion loss effect determines the collection efficiency of nanoparticles in the ESP. The collection efficiency of nanoparticles decreased continuously with decreasing particle diameter. This indicates that the partial charging effect of 10-nm-class nanoparticles is more dominant than their diffusion loss effect in the ESP for nanoparticles in the particle size range of less than 10 nm. The charging ratios based on unipolar diffusion charging calculations were in good agreement with the experimental collection efficiencies for nanoparticles less than 10 nm in diameter

[en] The results of the remote handling and remote maintenance testing at the Remote Maintenance Test Facility (RMTF) from July 1, 1978, through June 30, 1979, are presented. Specific test arrangements and test results from the RMTF of such items as high-efficiency particulate air (HEPA) filter disposal, solids removal equipment, and sample transfer container capper/decapper in support of several projects are discussed

[en] The filter device consists of filter chambers having got the cross-sectional shape of a polygon, the angle of which is adepted to the angle of repose of the filling material, e.g. charcoal, and which is horizontally blown against by the gas flow to be cleaned. Each chamber consists of two subchambers which may be filled with different filling material and which are separated laterally resp. from one another by means of partition walls permeable to gas. The filter material can be changed independently in both subchambers, no direct connection between the sides for supply air and purified air being created, thus increasing the economy. In addition, neighboring filter chambers on their front sides are provided with a common supply or discharge chamber. By this means inlet and outlet nozzles are saved. (DG)

[en] The aim of this experimental standard is the determination of the general characteristics of air or gas filtration equipment for limiting enclosures in application of the standard M 62-202. Application are made on enclosures or enclosure lines used for works on radioactive materials, toxic or dangerous chemicals, materials sensitive to atmospheric components or requiring a steril atmosphere

[en] A structure design program was developed for Venturi scrubber working at the self-priming mode. This program proposed a complete logic for thermal parameters calculation and structure design of the throat. A revised calculation for resistance relationship was carried out based on experimental study. The relative error between revised results and experimental values is within 8.6%. (authors)