FIRE SAFETY AT NUCLEAR POWER PLANT
Most of the time, we are inclined to think that fires only happen to other people...not to me, not to my home. Most people may not be concerned with fire safety until it is too late. The best way to fight fire is to prevent it in the first place
Before discussing about fire safety at NPP first of all we should understand what is fire and type of fire
What is fire?
Fire is a form of combustion. Most typically, the word fire refers to the combination of the brilliant glow and large amount of heat released during a rapid, self-sustaining exothermic oxidation process of combustible gases ejected from a fuel. The flames are a body of gas that releases heat and light. Fires start when a fuel is subjected to heat or another energy source, e.g. a match or lighter, and are sustained by the further release of heat energy until all the combustible fuel is consumed.
Type of fire
F Class A: Fires that involve flammable solids such as wood, cloth, rubber, paper, and some types of plastics.
F Class B: Fires that involve flammable liquids or liquifiable solids such as petrol/gasoline, oil, paint, some waxes & plastics, but not cooking fats or oils.
F Class C: Fires that involve flammable gases, such as natural gas, hydrogen, propane, butane.
F Class D: Fires that involve combustible metals, such as sodium, magnesium, and potassium.
F Class E: Fires that involve any of the materials found in Class A and B fires, but with the introduction of an electrical appliances, wiring, or other electrically energized objects in the vicinity of the fire, with a resultant electrical shock risk if a conductive agent is used to control the fire.
F Class F: Fires involving cooking fats and oils. The high temperature of the oils when on fire far exceeds that of other flammable liquids making normal extinguishing agents ineffective
What is fire safety and why it is important at NPP
Now let’s understand what Fire safety is and why it is important at NPP? Fire safety is a component of Building Safety. It concerns safety measures to prevent the effects of fires and is the result of proper use of fire protection measures.
Fire is an important concern at nuclear plants, because it has the potential to impact critical systems needed to safely maintain and shut down the reactor. Let’s discuss about one fire incident occurred at Browns Ferry NPP.
On March 22, 1975, workers at the Browns Ferry plant in northern
Workers tried to extinguish the fire and notified the control room. Shortly afterward, a municipal fire department arrived at the scene. Operators manually shut down both reactors and kept the plant in a safe condition throughout the incident. However, several factors hampered firefighting efforts, including a shortage of emergency breathing gear and plant operators’ reluctance to use water in electrical areas.
Four days later, the NRC(Nuclear regulatory control) appointed a panel to study the incident. Its February 1976 report identified a number of needed improvements in fire protection programs. Citing “the defense-in-depth” approach toward plant safety, however, the report found that public health and safety were protected during the incident, despite significant shortcomings in fire protection.
The report established that the three hallmarks of nuclear plant fire protection are to:
F prevent fires from starting
F quickly detect and extinguish fires to limit damage
F design plants to minimize damage to essential functions and ensure safe shutdown.
Fire safety at NPP: for preventing fire at Nuclear power plant we are following the defense in depth philosophy.
Defense-in-Depth philosophy: there are multiple approaches to fire protection at a nuclear plant. Prevention programs, such as plant design, administrative procedures, inspections and employee training, ensure the safe control of combustible materials and ignition sources. Detection and suppression systems and trained personnel are ready to control and extinguish quickly any fire that might occur..
Plant design: fire prevention program start from design stage it self.
Some examples are as follows:
F Providing proper fire exits and maintaining proper signage of them ( exit signs pointing to them that can function in a power failure)
F Placing fire extinguishers and fire alarms in easily accessible places.
F Providing sophisticated fire protection system for detecting the fire and extinguish the fire.
F Plant design such that it minimize the effect of fires on essential functions, using combustible-free separation, fire barrier, and fire detection and suppression systems between one set of systems and its back-up set.
Maintenance: Routinely inspection and preventing maintenance should be carried out to insure:
F Proper function of fire alarm control panels for quick detection and warning of fire.
F Properly storing/using of material , that may be needed inside the building for storage or operational requirements
F maintaining a complete inventory of fire stops
F Good condition of fire fighting system and equipments.
Administrative Controls for maintaining a facility and conducting oneself in accordance with the provisions of the fire code, from the moment that the plant construction started. This is based on thorough knowledge of the code by the administration and ensuring that the employees or operators of the plants are fully aware of the currently applicable regulations, including supplementary documents that may be applicable, which are referenced in the fire code.
Administration should limit the introduction of combustible materials into safety-related areas of the plant, strictly controlling their handling, and storage.
Training: Employees receive mandatory fire prevention training that begins with the administrative controls that govern their particular line of work. This includes training for:
F general fire protection
F fire watch
F fire department and brigade
F Maintenance.
Fire Watches Plants use fire watches when normal fire protection equipment is not functional—while being serviced, for example. Employees receive special training that includes the location and use of fire extinguishers and other fire protection equipment. Either fixed or roving fire watches are used, depending on the situation.
Sharing Industry Experience: The nuclear power industry places great value on sharing lessons learned from experience. Experience People share the knowledge on removing the bottle necks and solution to unseen emergency crises.
Conclusion: As we Know that “prevention is better than cure”, if we follow the defense in depth philosophy we will be able to prevent fire at nuclear power plant.
“INVEST IN FIRE SAFETY IT IS BLUE CHIP”
The End
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