Craft – Control Room Accident Filtration

Abstract

In the very unlikely case of severe accidents, radioactive noble gases will be released from nuclear power plant into the plant environment. Noble gases are a large part of the radioactivity released into the environment during containment venting activities or via potential containment bypass scenarios. To ensure that the workforce’s exposure to radiation doses does not exceed specified limits (according to OECD recommendation, doses within the control room should be kept below 100 mSv over a 7-day period), special measures need to be taken both during and after a severe accident to prevent activity from entering the control rooms.One of AREVA´s new innovative products is called CRAFT (Control Room Accident Filtration System), which is a control room noble gas retention unit. It ensures safe working conditions in habitable rooms during severe accidents through the reduction of dose exposure due to noble gas release. The CRAFT module can be used to protect:

• control rooms,
• emergency response centers,
• or other rooms designated for prolonged use during accidents

CRAFT retains noble gases by means of dynamic adsorption from the incoming fresh air. If not already implemented in existing air conditioning systems, the noble gas retention unit can be enhanced by an aerosol and iodine filtration unit.CRAFT’s operation time is unlimited. It is designed to operate through a complete accident progression and is suitable even in the case of multiple venting scenarios. Moreover, CRAFT covers scenarios on NPP sites with more than one unit.CRAFT can be used for all types of rooms requiring protection, independent of the type of NPP. The number of people inside the room is the main factor for the dimensioning of CRAFT. The system can be installed inside or outside existing buildings. It can also be provided as a mobile solution. Another important characteristic of CRAFT is its low maintenance.