Nuclear Facilities fire prevention
Oxygen reduction can reduce the risk of a catastrophic fire accident in a nuclear station dramatically
To achieve optimum safety, nuclear plants in the western world presently operate using a ‘defense-in-depth’ approach. This method employs a series of physical barriers between the radioactive reactor core and the environment, and utilizes multiple safety systems, each with backup and designed to accommodate human error. Safety systems account for about one quarter of the capital cost of such reactors.
The terrorist attack on the World Trade center in New York focused attention on the safety of nuclear power plants. In fact, the possibility of such a scenario has always been considered, and nuclear reactors are therefore more resistant to such assaults than virtually any other civil installations. However, since the attacks on 11 September, many countries have admitted that few nuclear reactors could cope with large aircraft crashes. Perhaps the clearest statement came on 21 September from the US nuclear Regulatory Commission, which is responsible for 103 reactors. “The NRC did not specifically contemplate attacks by aircrafts such as Boeing 757s or 767s, and nuclear power plants were not designed to withstand such crashes,” it said.
No one can be sure what would happen if a hijacked airliner plunged into a nuclear power station. The impact would almost certainly break open active circle tubing. The accompanying explosion would fling a plume of radioactivity into the atmosphere, initiating multiple fires. Afterwards, both burning fuel and structural elements would continue to pump radioactivity into the air. Putting this fire out wouldn’t be easy; fire crews struggled to dampen down the fire after the Pentagon crash on September 11th-and they didn’t have to contend with deadly radiation.
What should be done in the face of such a threat, except measures already in place to prevent planes from being hijacked, and to ensure that any plane that gets hijacked is shot down before it reaches the intended target? A catastrophic fire accident in a nuclear station could cause unimaginable damage with many of fatalities and significant long-term health hazards. FirePASS® can reduce this risk dramatically.
A combination of the fire-preventive normobaric hypoxic environment and fire suppression system (FirePASS-PS) provides the ultimate solution of the fire safety problem in nuclear power plants and installations.
Let us follow up the scenario of a major accident in a nuclear power plant considering what would differ if the reactor building was protected by FirePASS®. In this case the building would be constantly ventilated with FirePASS-PA agent, regenerated inside the building in order to maintain a comfortable atmosphere for personnel, and an additional amount of the compressed FirePASS-SA agent would be available for instant release. With FirePASS® installed the fire could by no means ignite or sustain itself inside the building.
In the case of a direct impact of a large plane the structural damage is inevitable. Depending on the size of the opening, caused by explosion, a significant amount of fuel could be injected inside the building. No currently available fire safety system could prevent ignition of this fuel.
However, FirePASS® would completely prevent and suppress propagation of flame inside the building, in spite of the abundance of jet fuel available for combustion. Due to the large amount of agent inside the building the flame could not initiate, and certainly could not persist and propagate, because fuel could not burn in this environment. On the other hand, additional release of FirePASS-SA would ventilate the inner room of the damaged building, thus maintaining the breathable fire-suppressive atmosphere at a slightly positive pressure and preventing a secondary ignition from electric short circuits or from any other source. Personnel could have immediate access to the damaged equipment in order to minimize radioactive pollution.
As an additional benefit, the inhalation of hypoxic air with oxygen concentration of about 10% is proven to induce radioprotective effect against X-rays and Gamma-rays. This effect is applied in cancer radiotherapy to protect healthy tissues and can help the nuclear facility personnel for short-time radioprotection in urgent situations.