Hollow-Fiber Membrane Based Micro-Filtration Technology for the Treatment of Low Level Nuclear Laundry Waste and Floor Drain Water

Abstract

A commonly used treatment for laundry waste and floor drain water in a nuclear power plant (NPP) in China involves filtration, followed by passing through a mixed ion exchange bed or evaporator. Due to the presence of foam and suspended solid in the laundry waste, the treatment systems require frequent maintenance and have a short filter service life. Pall ARIA™ platform, a hollow-fiber membrane based Micro-Filtration (MF) technology, was recently used at a German nuclear power plant to upgrade the low level radioactive laundry waste treatment system. The MF system with 0.1 μm average pore size and totally automated backwashable design was able to successfully concentrate the low level radioactive waste before it was sent to the evaporator. An 18-month long pilot test of the MF system, with a flow capacity of 3–6 m3/hr, using 3 modules, was performed at the 1300 MW, Pressurized Water Reactor (PWR) nuclear power plant, at Phillipsburg, Germany, to substitute its legacy centrifuge separators in waste water treatment system. During the long pilot testing, the MF technology amply demonstrated its capability for consistent high particulate removal efficiency, safe & reliable operation and high availability with average recovery rate of 95%. An average activity of 17900 Bq/m3 was reported in the filtrate. The 20X concentrated stream from the MF system was processed by the evaporator. The paper discusses the current liquid radwaste treatment practices in China, and the details of 18-month long trial of the MF system at Phillipsburg NPP.