The case for improved HEPA-filter mechanical performance standards revisited
- New Mexico State Univ., Las Cruces, NM (United States)
Under benign operating conditions, High Efficiency Particulate Air (HEPA) filter units serve as reliable and relatively economical components in the air cleaning systems of nuclear facilities worldwide. Despite more than four decades of filter-unit evaluation and improvements, however, the material strength characteristics of the glass fiber filter medium continue to ultimately limit filter functional reliability. In worst-case scenarios involving fire suppression, loss-of-coolant accidents (LOCA`s), or exposure to shock waves or tornado induced flows, rupture of the filter medium of units meeting current qualification standards cannot be entirely ruled out. Even under so-called normal conditions of operation, instances of filter failure reported in the literature leave open questions of filter-unit reliability. Though developments of filter units with improved burst strengths have been pursued outside the United States, support for efforts in this country has been comparatively minimal. This despite user requests for filters with greater moisture resistance, for example. Or the fact that conventional filter designs result in not only the least robust component to be found in a nuclear air cleaning system, but also the one most sensitive to the adverse effects of conditions deviating from those of normal operation. Filter qualification-test specifications of current codes, standards, and regulatory guidelines in the United States are based primarily upon research performed in a 30-year period beginning in the 1950`s. They do not seem to reflect the benefits of the more significant developments and understanding of filter failure modes and mechanisms achieved since that time. One overseas design, based on such knowledge, has proven reliability under adverse operating conditions involving combined and serial challenges. Its widespread use, however, has faltered on a lack of consensus in upgrading filter performance standards. 34 refs., 2 figs., 3 tabs.
- Research Organization:
- Harvard Univ., Boston, MA (United States). Harvard Air Cleaning Lab.; USDOE Assistant Secretary for Environment, Safety, and Health, Washington, DC (United States). Office of Environmental Guidance; US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Office of Nuclear Regulatory Research; International Society of Nuclear Air Treatment Technologies, Inc., Batavia, OH (United States)
- OSTI ID:
- 567243
- Report Number(s):
- NUREG/CP-0153; CONF-960715-; ON: TI97008959; TRN: 98:003317
- Resource Relation:
- Conference: 24. nuclear air cleaning and treatment conference, Portland, OR (United States), 15-18 Jul 1996; Other Information: PBD: Aug 1997; Related Information: Is Part Of Proceedings of the 24. DOE/NRC nuclear air cleaning and treatment conference; First, M.W. [ed.] [Harvard Univ., Boston, MA (United States). Harvard Air Cleaning Lab.]; PB: 1022 p.
- Country of Publication:
- United States
- Language:
- English
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