chernobyl nuclear accident

of 12 /12
Chernobyl Nuclear Chernobyl Nuclear Disaster Disaster

Author: triptiverve

Post on 18-Jun-2015




3 download

Embed Size (px)


Chernobyl Nuclear Accident- ppt


Chernobyl Nuclear Disaster

Where is Chernobyl???

The V.I. Lenin Memorial Chernobyl Nuclear Power Station is a nuclear power plant near the city of Prypiat, Ukraine, 18 km northwest of the city of Chernobyl, 16 km from the border of Ukraine and Belarus, and about 110 km north of Kiev. It was the site of the Chernobyl disaster in 1986, but due to high power demand, continued to operate until December 2000. Workers remain at the site as the remaining three reactors at the Chernobyl plant, although no longer in operation, still contain nuclear fuel which needs to be monitored around the clock.

Chernobyl Nuclear PlantData Country Start of commercial operation Ceased Operation Reactors Reactors (Active) Reactors (Shut Down) Reactors (Canced) Power Capacity

Chernobyl Nuclear Reactor

Ukraine 1977 2000 0 (0 MW) 4 2 (2000 MW) 4000 MW 0 GWh 0 GWh

Total Power Generation (in 2008) Average Annual Generation (last 5 years)

Nuclear Accidents in ChernobylAccidents1982

In 1982, a partial core meltdown occurred in reactor no. 1 at the Chernobyl plant. Due to the secret policy of the Soviet Union, the extent of the accident was not made public until years later. The reactor was repaired and put back into operation within months. 1986

On April 26, 1986, a disaster occurred at reactor no. 4, which has been widely regarded as the worst accident in the history of nuclear power. As a result, reactor no. 4 was completely destroyed and has since been enclosed in a concrete sarcophagus to prevent further escape of radiation. 1991

In 1991, during a scheduled shutdown, a fire broke out in reactor no. 2's turbine, causing severe damage to the reactor building. It was then decided that reactor no. 2 would not be returned to operation because of the severity of the damage.

Chernobyl Nuclear Disaster:1986

Chernobyl Nuclear Disaster 1986

The Chernobyl accident in 1986 was the result of a flawed reactor design that was operated with inadequately trained personnel and without proper regard for safety. The resulting steam explosion and fire released at least five percent of the radioactive reactor core into the atmosphere and downwind. 28 people died within four months from radiation or thermal burns, 19 have subsequently died, and there have been around nine deaths from thyroid cancer apparently due to the accident: total 56 fatalities as of 2004. An authoritative UN report in 2000 concluded that there is no scientific evidence of any significant radiation-related health effects to most people exposed. This was confirmed in a very thorough 2005-06 study.

The Chernobyl disaster triggered the release of substantial amounts of radiation into the atmosphere in the form of both particle and gaseous radioisotopes, and is the most significant unintentional release of radiation into the environment to date. On 2-3 May, some 45,000 residents were evacuated from within a 10 km radius of the plant, notably from the plant operators' town of Pripyat. On 4 May, all those living within a 30 kilometer radius - a further 116 000 people from the more contaminated area were evacuated and later relocated. About 1,000 of these have since returned unofficially to live within the contaminated zone.

Effects on Environment and Health

In 1989 the World Health Organisation (WHO) first raised concerns that local medical scientists had incorrectly attributed various biological and health effects to radiation exposure. An International Atomic Energy Agency (IAEA) study involving more than 200 experts from 22 countries published in 1991 was more substantial. In the absence of pre-1986 data it compared a control population with those exposed to radiation. Significant health disorders were evident in both control and exposed groups, but, at that stage, none was radiation related. Subsequent studies in the Ukraine, Russia and Belarus were based on national registers of over one million people possibly affected by radiation. By 2000 about 4000 cases of thyroid cancer had been diagnosed in exposed children. Among these, nine deaths are attributed to radiation. People in the area have suffered a paralysing fatalism due to myths and misperceptions about the threat of radiation, which has contributed to a culture of chronic dependency. Some "took on the role of invalids. Mental health coupled with smoking and alcohol abuse is a very much greater problem than radiation.

Silent Screams

What happened after the disaster???

In the early 1990s some US$400 million was spent on improvements to the remaining reactors at Chernobyl, considerably enhancing their safety. Energy shortages necessitated the continued operation of one of them (unit 3) until December 2000. (Unit 2 was shut down after a turbine hall fire in 1991, and unit 1 at the end of 1997.) Workers and their families now live in a new town, Slavutich, 30 km from the plant. This was built following the evacuation of Pripyat, which was just 3 km away.

Chernobyl: Today

The Chernobyl unit 4 is now enclosed in a large concrete shelter (sacrophagus). The international Shelter Implementation Plan in the 1990s involved raising money for remedial work including removal of the fuelcontaining materials. Some major work on the shelter was carried out in 1998 and 1999. Some 200 tonnes of highly radioactive material remains deep within it, and this poses and environmental hazard until it is better contained. A New Safe Confinement structure will be built by the end of 2011, and then will be moved into place on rails. The 2005 Chernobyl Forum report said that some seven million people are now receiving or eligible for benefits as "Chernobyl victims", which means that resources are not targeting the needy few percent of them. Remedying this presents daunting political problems however. In January 2008 the Ukraine government announced a 4-stage decommissioning plan which incorporates the above waste activities and progresses towards a cleared site.

The Worst Disaster Of Its Kind