NUCLEAR CRISIS OF JAPAN (FUKUSHIMA – A DETAILED ANALYSIS) Presented by YATRA…
Types of Nuclear reactors• Pressurized water reactors• Pressurized heavy water reactors• Boiling water reactors• Advanced Boiling Water reactors• Pool water reactors• Liquid metal cooled reactors and so on
Generation of Nuclear Reactors
Fukushima Nuclear Plant• This Daiichi Nuclear Power Plant is a BWR type located in the town of Okuma in the Futaba District of Fukushima Prefecture, Japan, first commissioned in 1971.• It houses six reactors, all of same type falls under the Generation II• These reactors are capable of producing a power of 4.7Gwe.• Fukushima I is one of the 15 largest nuclear power stations in the world.• These reactors used Low Enriched Uranium as fuel.
Basic Diagram of a BWR
Model of Reactor In Fukushima
Timeline of Nuclear disaster• Friday, 11 March 14:46A 9.0 magnitude earthquake strikes off the coast of Honshu Island at a depth of about 24 kilometres (15 mi). Fukushima I power plants nuclear reactors 1, 2, and 3 are automatically shut down by the shake. Nuclear reactors 4, 5, and 6 were undergoing routine maintenance and were not operating, (reactor 4 was defueled Nov 2010). The tremor has the additional effect of causing the power plant to be cut off from the Japanese electricity grid, however, backup diesel generators kick in to continue cooling.• Saturday,12 March 15:36Unit 1 at Fukushima I: cameras document a massive hydrogen explosion on the outer structure of one of four buildings at the plant. It also documents the outer structure collapsing. TEPCO 3 hrs later announces that four persons who are employed at the power plant have been injured.
• Monday, 14 March 11:15The outer building surrounding Unit 3 of Fukushima I explodes• Tuesday 15 March 06:14 (approximate)A third explosion occurs at Fukushima I, unit 2 and damages the containment building
Overview of Reactors
Commendable Restoration of Japan Govt.• Soldiers from Japans Self Defense Force and Tokyo firefighters are helping to douse the reactors and fuel-rod pools, and the "Fukushima Fifty" have been joined by hundreds of other technicians apparently willing to risk death to prevent another Chernobyl. » Continued…………
• U.S. Energy Secretary Steven Chu said Sunday that while we have incomplete information, it appears that "with each passing hour, each passing day, things are more under control.“• Tepco has been able to restore electricity at three of the six reactors• Helicopter drops of seawater "appear to have created a modicum of stability,“
Current status of reactors• Reactor No. 1 Seawater did more damage to Reactor 1 than previously believed, and the unit will take longer to repair than expected• Reactor No. 2 Coolant pumps and electrical components were damaged at Reactor No. 2, and the earliest those parts can be replaced• Reactor No. 3 Officials say fuel inside the reactor has been partially exposed as temperatures rose and water levels dropped. Workers have injected seawater into the reactor. A pool containing spent fuel rods is a chief concern. Firefighters continued dousing the pool with water Tuesday to keep those rods, which contain radioactive material, cool. Continued…………
• Reactor No. 4 The reactor does not contain any fuel rods, but the pool that houses the spent fuel rods is a chief concern. Crews used cement pumps to spray water on the pool Tuesday to keep the fuel rods cool.• Reactor No. 5 , 6 Workers created vent holes in the buildings roof to avoid a hydrogen explosion. The cooling system is working and powered by a generator.
Harmful radiation spread zone
Conclusion• Here we conclude in a point of a engineering student, Being a second generation power reactor it has undergone some operation failure… But with just this we cant claim the nuclear power generation is a dangerous since it is the only better solution to overcome the power necessity in this machine world. In India we have almost all working nuclear powerstation falling under the catogory of Gen III or III+ with additional safety measures been employed. Also our seismic zone falls under the catogory of low possibilities for earthquake with such magnitude and hence low risk involved.