Degradation of HEPA filters exposed to DMSO
- Lawrence Livermore National Laboratory, CA (United States); and others
Dimethyl sulfoxide (DMSO) sprays are being used to remove the high explosive (HE) from nuclear weapons in the process of their dismantlement. A boxed 50 cmf HEPA filter with an integral prefilter was exposed to DMSO vapor and aerosols that were generated by a spray nozzle to simulate conditions expected in the HE dissolution operation. After 198 hours of operation, the pressure drop of the filter had increased form 1.15 inches to 2,85 inches, and the efficiency for 0.3 {mu}m dioctyl sebacate (DOS) aerosols decreased form 99.992% to 98.6%. Most of the DMSO aerosols had collected as a liquid pool inside the boxed HEPA. The liquid was blown out of the filter exit with 100 cmf air flow at the end of the test. Since the filter still met the minimum allowed efficiency of 99.97% after 166 hours of exposure, we recommend replacing the filter every 160 hours of operation or sooner if the pressure drop increases by 50%. Examination of the filter showed that visible cracks appeared at the joints of the wooden frame and a portion of the sealant had pulled away from the frame. Since all of the DMSO will be trapped in the first HEPA filter, the second HEPA filter should not suffer from DMSO degradation. Thus the combined efficiency for the first filter (98.6%) and the second filter (99.97%) is 99.99996% for 0.3 {mu}m particles. If the first filter is replaced prior to its degradation, each of the filters will have 99.97% efficiency, and the combined efficiency will be 99.999991%. The collection efficiency for DMSO/HE aerosols will be much higher because the particle size is much greater.
- Research Organization:
- USDOE Assistant Secretary for Environment, Safety, and Health, Washington, DC (United States). Office of Environmental Guidance; Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research; International Society of Nuclear Air Treatment Technologies, Inc., Batavia, OH (United States); Harvard Univ., Boston, MA (United States). Harvard Air Cleaning Lab.
- OSTI ID:
- 95689
- Report Number(s):
- NUREG/CP--0141; CONF-940738--; ON: TI95007828
- Country of Publication:
- United States
- Language:
- English
Similar Records
Development of an air cleaning system for dissolving high explosives from nuclear warheads
Development of an air cleaning system for dissolving high explosives from nuclear warheads