Мухаммад Нур Rashidi бен ми росли (Muhammad Nur Rashidi Rosli)
Physics, PPST, UMS
The worst manmade disaster in human history
"This is the one place where you could understand how the world would be after a nuclear war,"
(Dr. Vladimir Chernousenko)
Saturday, 26 April 1986:
The accident at reactor 4 occurred during an experiment to test a potential safety emergency core cooling feature. Chernobyl nuclear power plant located 100 km to the north of Kiev, in Ukraine and 20 km south of the border with Belarus, which was under the direct jurisdiction of the central authorities of the Soviet Union
• 3 workers died on the night of the accident
• 28 people died within a few weeks
• Radiation injuries to over a hundred
• 115,000 people evacuated
• 220,000 people relocated
• 6,000 cases of thyroid cancer
• Large areas were contaminated
The Chernobyl disaster is the worst nuclear power plant accident in history in terms of cost and resulting deaths and is one of only two classified as a level 7 event (the maximum classification) on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster in 2011)
введення
RBMK Reactor
(Reaktor Bolshoy Moshehnosty Kipyashiy)
Reactor plant scenario
1. As the reaction occurs, the uranium fuel becomes hot
2. The water pumped through the core in pressure tubes removes the heat from the fuel
3. The water is then boiled into steam
4. The steam turns the turbines
5. The water is then cooled
6. Then the process repeats
The occurrence of the accident
Reactor crew preparing for a test to
determine how long turbines would spin and supply power following a loss of main
electrical power supply
Plants known to be very unstable at low power settings
Disabling of automatic shutdown
mechanisms, preceded the attempted test
early on 26 April
As flow of coolant water diminished, power output increased
When the operator moved to shutdown the reactor from its unstable condition arising from previous errors, a peculiarity of the design
caused a dramatic power surge
The fuel elements ruptured and the resultant explosive force of steam lifted off the cover plate of the reactor
Releasing fission products to the atmosphere
Second explosion threw out fragments of burning fuel and graphite from the core and allowed air to rush in
Causing the graphite moderator to burst into flames
Over 1200 tones of graphite- burned for 9 days, causing the main release of
radioactivity into the environment
A total of about 14 Ebq (10^18 Bq) of
radioactivity was released, half of it
being biologically-innert noble gases
Radionuclide release
• Iodine-131 and caesium-137 are responsible for most of the radiation exposure received
• All the noble gases, including krypton and xenon, contained within the reactor were released immediately into the atmosphere by the first steam explosion
• 50 to 60% of all core radio-iodine in the reactor, containing about 1760 PBq, which in mass units is 0.4 kg of iodine-131, was released, as a mixture of sublimed vapor, solid particles, and organic iodine compounds
• 20 to 40% of all core caesium-137 was released, 85 PBq in all
• Cesium was released in aerosol form; caesium-137, along with isotopes of strontium, are the two primary elements preventing the Chernobyl exclusion zone being re-inhabited
• The caesium-137 activity represented by 85 PBq would be produced by 24 kilograms of caesium-137. Cs-137 has a half life of 30 years
• Tellurium-132, half life 78 hours, an estimated 1150 PBq was released.
• Xenon-133, the total radioactivity atmospheric release is estimated at 5200 PBq, Xe-133 has a half-life of 5 days
Extent of the release
• The explosions that ruptured the Chernobyl reactor vessel and the consequent fire that continued for 10 days
• The greatest deposits of radionuclides occurred over large areas of the Soviet Union surrounding the reactor in what are now the countries of Belarus, the Russian Federation and Ukraine
• Estimated 350,000 emergency and recovery operation workers, including army, power plant staff, local police and fire services, were initially involved in containing and cleaning up the accident in 1986-1987
• More than five million people live in areas of Belarus, Russia and Ukraine that are classified as "contaminated" with radionuclides due to the Chernobyl accident (above 37 kBq m2 of 137Cs)
• Amongst them, about 400 000 people lived in more contaminated areas - classified by Soviet authorities as areas of strict radiation control (above 555 kBq m-2 of 137Cs)
• Of this population, 116 000 people were evacuated in the spring and summer of 1986 from the area surrounding the Chernobyl power plant (designated the "Exclusion Zone") to non-contaminated areas. Another 220 000 people were relocated in subsequent years.
• Unfortunately, reliable information about the accident and the resulting dispersion of radioactive material was initially unavailable to the affected people in what was then the Soviet Union and remained inadequate for years following the accident
• This failure and delay led to widespread distrust of official information and the mistaken attribution of many ill health conditions to radiation exposure
• An area originally extending 30 kilometers (19 mi) in all directions from the plant is officially called the "zone of alienation“
• It is largely uninhabited, except for about 300 residents who have refused to leave
• The area has largely reverted to forest, and has been overrun by wildlife because of a lack of competition with humans for space and resources
• Even today, radiation levels are so high that the workers responsible for rebuilding the sarcophagus are only allowed to work five hours a day for one month before taking 15 days of rest. Ukrainian officials estimate the area will not be safe for human life again for another 20,000 years
Short &
Long term effect
International spread of radioactivity
Residual radioactivity in the environment
•Rivers, lakes and reservoirs
•Groundwater
•Flora and fauna
Fauna and vegetation Socio
economical impact Health effect
•Thyroid cancer
•Leukemia
•Cataracts
•Cardiovascular disease
•Mental health and psychological effects
•Reproductive and hereditary effects
bodies &
individuals involved
Soviet Union
Chernobyl Power Station
fire fighter
Institute of Atomic
Energy
UN
IAEA UNSCEAR
Past 27 years
Chernobyl Humanitarian Assistance and Rehabilitation Programme (CHARP)
• Program running since 1990 by International Federation of Red Cross and Red Crescent Societies with local societies
• address basic health needs of those living in the regions of the 3 countries affected (Belarus, Russia, Ukraine)
• core activity is cancer screening, provide psychosocial support, distribute multivitamins to children living in radiation
contaminated areas
Chernobyl Recovery and Development Programme (CRDP)
– developed by the United Nations Development Program, initiated 2002
– Aim: return to normal life by providing support to the government of Ukraine for elaboration and
implementation of development-oriented solutions for the regions, mitigate long-term social, economic and environmental consequences and create more favorable living conditions and to promote sustainable human development in affected regions
International Atomic Energy Agency (IAEA)
– employs a safeguards system which is among the most advanced at any safeguarded nuclear facility – remote monitoring, on-site inspections, seals to ensure the non-diversion of nuclear material
Chernobyl Forum
• The Chernobyl Forum is the name of a group of UN agencies, founded on 3–5 February 2003 at the IAEA (International Atomic Energy Agency) Headquarters in Vienna, to scientifically assess the health effects and environmental consequences of the Chernobyl accident and to issue factual, authoritative reports on its environmental and health effects
• Nine UN organizations are involved in the Chernobyl Forum:
– the IAEA (International Atomic Energy Agency) – the FAO (Food and Agriculture Organization)
– the OCHA (United Nations Office for the Coordination of Humanitarian Affairs) – the UNDP (United Nations Development Programme)
– the UNEP (United Nations Environment Programme)
– the UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation)
– the WHO (World Health Organization) – the World Bank
• The Chernobyl Forum also comprises the governments of Belarus, Russia and Ukraine.
Mitigation & Action
• Construction of the Shelter between May and November
1986, aiming at environmental containment of the damaged reactor, reduced radiation levels on-site and prevented
further release of radionuclides off-site.
• The construction of the New Safe Confinement (NSC) is expected to allow for the dismantlement of the current
Shelter, removal of highly radioactive Fuel Containing Mass
(FCM) from Unit 4, and eventual decommissioning of the
damaged reactor
• Construction and operation of the NSC and relevant engineering infrastructure;
• Defueling, decommissioning and dismantling of Units 1, 2 and 3 of the nuclear power plant and the Shelter;
• Construction of facilities for processing and
management of radioactive waste, in particular
• a deep geological repository for high-activity and long-lived radioactive material;
• Development of natural reserves in the area that remains closed to human habitation; and
• Maintenance of environmental monitoring and
research activities.
Lesson Learnt
Chernobyl a steppingstone for a new philosophy – new term in nuclear energy “safety culture”
• Nuclear power plants (NPPs) as units of national importance
• Safety first-Priority given to people’s safety and preservation of the environment rather than productivity
• Overhaul of current and future projects with focus on risk minimization
• Emergency preparedness and safety measures
• Understand, respect and minimize risk
• International and national emergency response systems, highly involving the community
• Adequate radiation measuring technology in place
• NPP community for knowledge exchange (WANO) and international scientific co-operation
• Constant quality and safety control and measurement
• Continuous improvement of technology and safety measures
• Communication is key
