Air Cleaning Systems
Safety-related air cleaning systems for nuclear power plants go beyond the normal role of air filters. These systems are used to prevent the release of radioactive airborne contaminants to the working environment of the nuclear plant and the outside atmosphere. As Engineered Safeguards Systems, they are used to remove particulates and radioactive iodine from contaminated air.
Components in an AAF air cleaning system, installed in a series of banks in a filter house, are built by AAF, designed with the experience gained by over 90 years in air filter manufacture. AAF’s unique integration as a system supplier and breadth of industrial experience in air cleaning systems have allowed us to apply effective and proven components to these nuclear filter systems through the years.
Filter System Design
Filter systems, when designed in an enclosed structure, are shop-fabricated housings of painted carbon steel or stainless steel with structural supports and internal framing members to support the components. These components typically include moisture separators, prefilters and HEPA filter banks, charcoal adsorbers in trays or rechargeable beds, and auxiliary components such as flow, temperature, humidity sensing instruments, fire detection/water deluge systems, electric heaters, cooling coils, and fan/motor sets.
Flow ranges are from several hundred to 30,000 cfm or more. In addition, filter banks alone are used in certain nuclear power plant applications. These are frame sections for mounting banks of filter cells, medium efficiency or HEPAs, in site assembled plenums or ducts.
Air Conditioning Systems
As with nuclear air cleaning systems, certain air cooling in nuclear power plants is vital to the safe operation of the plant in normal conditions and in providing cooling needed for safety shutdown should emergency conditions occur. Containment coolers, air handling units and other commercial or safety class air coolers are used to maintain atmospheric temperatures and as special area coolers for essential plant equipment or operating areas. At the centre of most applications will be an AAF heating or cooling coil. AAF’s nuclear coils are custom-designed to meet any application and can be supplied and tested to ASME “N” stamp requirements.
AAF NES can provide assistance in refitting, reconditioning or rebuilding existing heating, cooling or filtration equipment. We can supply safety-related components via commercial grade dedication utilising our NQA-1 programme and safety-related vendors.