In-Place Testing of Multiple Stage Filter Systems Without Disruption of Plant Operations in the Plutonium Facility at Los Alamos

摘要

The Los Alamos National Laboratory Plutonium Facility has a number of multiple-stage air-cleaning systems. These systems operate on a continuous basis and economic considerations require that shutting down of the ventilation systems due to in-place testing be kept to a minimum. Earlier methods of testing multiple-stage filter systems required scheduled shut down of the filter system. Methods such as injecting the test aerosol between the stages have proven costly because of the need to install temporary injection ducts and completely close off the ventilation from the process area. Also, additional personnel were needed to install and move injection and bypass ducts from one system to another. After considering these costly methods, we improved our current methods of testing to prevent interrupting of plant operations. The modified procedure uses a laser particle size spectrometer that has the capability of counting single particles downstream of two filter stages where decontamination factors of the first stage and overall system effectiveness is established. This procedure is similar to that of Nuclear Standard NEF 3-4IT, In-Place Testing of HEPA filter systems by the Single-Particle, Particle-Size Spectrometer Method. Decontamination factors of 10 exp 9 are measured downstream of two stages. Particle size analyses of the challenge and the aerosol penetrating the first and second stages have been established. A cost estimation comparing two test methods shows considerable savings in operational costs. 6 references, 9 figures, 1 table. (ERA citation 09:039689)