FIRE PROTECTION ISSUES IN THE HOT CELLS OF A NUCLEAR FACILITY Ovidiu ICHIM Institute for Nuclear Research Pitesti - ROMANIA
GENERAL OVERVIEW Romania's nuclear energy program foresees for the safe and competitive operation of Units 1 and 2 (CANDU technology 700 MW each) from Cernavoda NPP, completion of Units 3 and 4 (same technology), building a new nuclear power plant, promoting the Generation IV advanced reactors on medium and long term, the safe disposal of radioactive waste and spent fuel. INR Pitesti has as field of activity the scientific research, design, technological development and scientific and technical responsibility for the development of nuclear energy in Romania. The INR ensures the operation, development and use of the infrastructure required to carry-out the research and development programs, education and training of specialists, as well as a sustained international cooperation, as essential elements for a sustainable nuclear energy sector. Also, INR promotes the development and application of nuclear technologies in medicine, industry or agriculture adding an important contribution to increasing the citizens life standard.
Post-Irradiation Examination Laboratory (PIEL) ACITIVITIES Post-irradiation examination of nuclear fuel irradiated in nuclear power reactors (Cernavoda NPP) or in research nuclear reactors (INR - TRIGA SSR / ACPR). Examination of structural materials used for nuclear reactors. Manufacturing and sale of sealed nuclear radiation sources and radioisotopes used in industry, agriculture and medicine. Monitoring and maintenance of SENTINEL industrial radiography devices used for Se-75, Ir-192, Co-60, and Yb-169 sealed nuclear radiation sources. Characterization of radioactive waste.
HOT CELL CHARACTERISTICS
FIRE PROTECTION OVERVIEW The INR have a special department created for emergency situation which is according with a senior manager of site and Romanian authorities. This department creates a fire protection program where are presented the responsibilities of any person who work on this site. This department develop and update the legislation and procedure on this domain. This department provide training for all staff. This department maintains and ensure proper functioning of equipment intervention.
FIRE PROTECTION PROGRAM OBJECTIVES Realizing and implementing a fire protection program for HOT CELLS Integrating a fire protection program for HOT CELLS in the INR overall risk management system PRINCIPLES Minimize both the probability of fire occurrence and the consequences resulting from fire Fire protection is an essential part of a nuclear safety/risk management in the nuclear facility. The program should establish the fire protection policy for the protection of structures, systems, and components important to safety at each nuclear facility and the procedures, equipment, and personnel required to implement the program at the nuclear facility site.
APPROACHES The fire protection program for PIEL approaches the fire protection problem through a series of protection features based on the following: FIRE PREVENTION (reduction of probability) FIRE DETECTION (early stage detection helps limiting damage) MITIGATION AND CONTROL OF FIRE (fire fighting systems, fire confinement, fire suppression) EMERGENCY RESPONSE (on-site fire brigade)
FIRE PREVENTION To ensure fire prevention different procedures were elaborated regulating the operations in the hot cells In the designing stage of the hot cells different security studies for the safe removal of excess heat from the storage shaft were taken into account. Also the possibility of criticality was addressed. The complex furniture for the equipment in the hot cells was also designed with emphasis on fire prevention. The electrical wiring insulation is designed to withstand intense radiation and heat and to prevent short-circuit. The fire protection department schedules and perform exercises / simulations for various interventions in emergency situations.
FIRE DETECTION Early stage detection of fires is very important in order to limit the damage. The hot cells are equipped with a fire alarm system which is made up of smoke and heat detectors, video cameras, connected to a central warning unit. The central warning unit relays the alarm signal to the on-site fire brigade and also provides location information. The fire alarm system and the emergency lighting are operated on a separate redundant power supply. The fire alarms are easily accessible anywhere in the building. There is a procedure in order to test on a daily basis the functionality of the fire alarm system. There is a continuously manned control room for receiving and acting on reported incidents and emergencies.
MITIGATION AND CONTROL OF FIRE The hot cells windows, walls, floors, ceilings and their supports are fire proof, acting as fire barriers. The ventilation openings through these fire barriers are also fire proof and have fire dampers designed to shutdown the ventilation system in a specific area upon confirmation of fire. Openings through the fire barriers for pipes, cable trays and robotic arms are sealed and closed to provide a fire resistance rating at least equal to that of the barrier itself. The hot cells are equipped with a gaseous fire suppression system using nitrogen gas. The nitrogen gas usage inside the hot cells in case of a fire is pressure regulated as to prevent radioactive particles migration.
EMERGENCY RESPONSE Is represented by the efforts made by a coordinated group of personnel to assess, control and mitigate hazardous events. At our nuclear facility we have an on-site fire brigade specially prepared for emergency response actions. They fulfil the role of first responder and also have an arrangement with offsite fire services when it is necessary to augment fire fighting capabilities. The alarm from the central warning unit is signalled in real time at the fire brigade. The fire brigade coordinates with the hot cell personnel in charge of local emergency response, locating the fire, limiting the damage and evacuating. They use different fire fighting techniques according with the type and location of the fire. The safe closing of nuclear facilities is carried out by the relevant personnel.
FEEDBACK ON THE DRAFT IAEA PUBLICATION WITH FIRE PROTECTION GUIDELINES In our opinion the draft IAEA publication with fire protection guidelines represents a comprehensive fire protection guidance which will be a solid base in implementing and upgrading any fire protection program. Although this draft is very extensive it must be always revised as to keep it up to date with developing technology in the field of fire protection. Our own programme follows the same principles described here, which proved to be very effective as we haven't had any incident in the entire operational life of the hot cells lab. Taking this in to account, in our opinion, this draft covers very well all the problems regarding the fire protection program.
Thank you!