[en] Calculations were performed to estimate the maximum credible flow rates of pressurized air into Plutonium Process Support Laboratories gloveboxes. Classical equations for compressible fluids were used to estimate the flow rates. The calculated maxima were compared to another's estimates of glovebox exhaust flow rates and corresponding glovebox internal pressures. No credible pressurized air flow rate will pressurize a glovebox beyond normal operating limits. Unrestricted use of the pressurized air supply is recommended

[en] The purpose of this invention is to prevent the spread of the dusts emitted throughout the entire volume of a glove box, thereby preventing the walls from becoming opaque, the concentration of dusts which can be dangerous in certain places and allowing the recuperation of a product, the cost of which could be high. This is achieved by means of an efficient system of distribution and take-up of the air or gas from the glovebox

[en] A numerical investigation has been carried out for the flow characteristics after exchange of some filters from the original layer to the new low pressure loss layer with equal filtering efficiency. The solution domain includes upper plenum, filter layer, clean space, access panels, and lower plenum. The concept of the distributed pressure resistance was applied to describe the momentum loss in filter layer and access panels. The evolution of the flow field is simulated using the low Reynolds number k-ε turbulent model and SIMPLE algorithm based on the finite volume method. As a result, after the exchange of filter layer the power requirement can be reduced by 8 - 9 percent. The results also demonstrate that the perpendicularity of the flow near access panels may become worse at new filter layer than original filter layer. But the situation can be recovered by adjusting the jopening ratio of access panels. (Author)

[en] Each new HEPA filter installation presents a different physical configuration based on the system requirements, the available space and designer preference. Each different configuration can result in variations of air flow uniformity inside the filter housing across the filter banks. This paper presents the results of air flow uniformity testing for six different filter housing/ductwork configurations and discusses if any of those variations in air flow uniformity is attributable to the difference in the physical arrangements for the six cases

[en] Rev. 1 to N509 and Rev. 1 to N510, the equipment and test standards originally published in 1975 and 1976 have been approved, printed and are now available, 1980 edition. The need for certain changes became evident as a result of using the original documents. One thing of interest is that adsorbent qualification now follows ASTM Standards which became available during the revision period. Appendix B to N509 has been expanded to provide guidance in determining maximum test leakage for ducts and housings. Tables listing minimum instrumentation for both ESF and Non-ESF air cleaning units have been added. N510 has had both appendices expanded to provide more detail on the significance of in-place leak tests and leak test procedures. These editions will be the last for these two standards

[en] This invention concerns improved appliances enabling granules to be compressed, evenly on the whole, in a hopper, filter or any other component to be filled with such granules. This criterion is particularly important in the case of air filters using granulated adsorbing coal for separating the radioactive substances in the air should an ccident occur in a nuclear power station

[en] We have made further progress in developing a cleanable steel fiber HEPA filter. We fabricated a pleated cylindrical cartridge using commercially available steel fiber media that is made with 1 μm stainless steel fibers and sintered into a sheet form. Test results at the Department of Energy (DOE) Filter Test Station at Oak Ridge show the prototype filter cartridge has 99.99% efficiency for 0.3 μm dioctyl phthalate (DOP) aerosols and a pressure drop of 1.5 inches. Filter loading and cleaning tests using AC Fine dust showed the filter could be repeatedly cleaned using reverse air pulses. Our analysis of commercially optimized filters suggest that cleanable steel HEPA filters need to be made from steel fibers less than 1 μm, and preferably 0.5 μm, to meet the standard HEPA filter requirements in production units. We have demonstrated that 0.5 μm steel fibers can be produced using the fiber bundling and drawing process. The 0.5 μm steel fibers are then sintered into small filter samples and tested for efficiency and pressure drop. Test results on the sample showed a penetration of 0.0015% at 0.3 μm and a pressure drop of 1.15 inches at 6.9 ft/min (3.5 cm/s) velocity. Based on these results, steel fiber media can easily meet the requirements of 0.03% penetration and 1.0 inch of pressure drop by using less fibers in the media. A cost analysis of the cleanable steel HEPA filter shows that, although the steel HEPA filter costs much more than the standard glass fiber HEPA filter, it has the potential to be very cost effective because of the high disposal costs of contaminated HEPA filters. We estimate that the steel HEPA filter will save an average of $16,000 over its 30 year life. The additional savings from the clean-up costs resulting from ruptured glass HEPA filters during accidents was not included but makes the steel HEPA filter even more cost effective. We also present the results of our evaluation of competing technologies with metallic and ceramic powder filters, ceramic fiber falters, and reinforced glass fiber filters. In general, the metallic and ceramic powder filters have pressure drops in excess of 25 inches of water for HEPA grade efficiencies and are therefore not viable candidates. The ceramic fiber filters cannot meet the HEPA efficiency because the fiber diameters are too large. The reinforced glass fiber filter is a promising candidate for the cleanable HEPA filter but requires additional development and testing to confirm its potential to be repeatedly cleaned. This report is based upon material extracted from a DOE technical review of the Mixed Waste Integrated Program and from the final report of a systems analysis of cleanable steel HEPA filters

[en] For the exchange of the filter elements formed like hoses, pockets, or bags a frame is used that can be drawn in or out. Its upper seal forms a partition that can be pushed with the help of a lift table together with the filter elements into a break point between clean- and dust air side. The frame can be moved with the help of a transporter with a drive-on platform. (RW)

[en] Several types of clean rooms are commonly in use. They include the conventional clean room, the horizontal laminar flow clean room, the vertical laminar flow clean room and a fourth type that incorporates ideas from the previous types and is known as a clean air bench or hood. These clean rooms are briefly described. The origin of contamination and methods for controlling the contamination are discussed

[en] Experimental data related to C₂HCl₃ (TCE) removal in dry and humid (200-1000 ppm of H₂O) air, respectively, in ambient conditions under electron beam irradiation in the dose range of 1-40 kGy has been published in the literature. Based on the experimental results a theoretical model of C₂HCl₃ decomposition was proposed for the kinetic mechanism of such process. The active radicals of Cl, O and OH play an important role in the decomposition of TCE. According to the calculations performed, the Cl^- dissociative electron attachment predominates in the initial stage of C₂HCl₃ decomposition. Cl radical accelerates this degradation by chain process in both humid and dry air, respectively. The OH radical produced in humid air also enhances the decomposition process of TCE. (authors)