Approved 10/27/97 REQUIREMENT H. Operations Off-Normal (4) Loss of any process ventilation system serving a confinement function which does not result in the loss of confinement. INTERPRETATION Do we declare an Off-Normal Occurrence every time we lose ventilation on a vessel or tank containing radioactive waste? Intent: The intent was to report the loss of a ventilation system that was designed to prevent a release to the environment. Additional Information: An OffNormal Occurrence is declared under this criteria only if the ventilation system serves as a confinement function. This depends on the design function of the tank or vessel and the attached ventilation system. On some tanks and vessels, the design function of the ventilation system is to prevent the buildup of hydrogen and organic vapors, not confinement, although it does provide an inherent measure of confinement capability. On other tanks or vessels, the design function may also be to maintain a negative pressure in the tank or vessel with an exhaust through a ventilation high efficiency air particulate (HEPA) filter which is the function of confinement. In this case, a loss of ventilation causing the negative pressure or differential pressure to decrease below allowable limits (loss of confinement) is reportable. |
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