Upgrade of Nuclear Power Plant Laundry Waste Floor drain Water Treatment System Utilizing Microfiltration

摘要

Conventional nuclear power plant laundry waste and floor drain treatment systems are based on decanting, followed by centrifuge separators and evaporators. They have limited removal efficiency for fine particles, resulting in poor reduction in radioactivity levels in the treated water. Separators suffer from foaming issues due to the presence of detergents and require frequent maintenance, exposing the workers to radiation. The 1468 MW Pressurized Water Reactor (PWR) nuclear power plant at KKP Phillipsburg, Germany evaluated a hollow-fiber membrane based Microfiltration (MF) technology for the concentration of the waste before it was sent to the evaporator. Following an 18-month long pilot test, the plant decided to purchase the totally automated, turn-key MF system based on a Pall's Aria platform. The MF system, with flow capacity of 3-6 m~3/hr, consists of 3 MF modules, associated pumps, tanks, valves and controls, all mounted on a compact skid. Over the 18-month long pilot testing, the MF technology amply demonstrated its capability for consistently high particulate removal efficiency, safe and reliable operation and high availability with an average recovery rate of 95%. Filtrate flux rates of up to 50 Liters/m~2/hr (LMH) were achieved during the trial, with only one chemical cleaning required during the period. The plant reported an average activity in the filtrate of 17,900 Bq/m~3, which meets the local requirement of 4,000 Bq/m~3 (as reported by the plant) for its release into the environment. The 20X concentrate stream from the MF system was processed by the evaporator. This presentation discusses the details of the MF system and its performance during the pilot test.