TEMAS RELACIONADOS COM O
ACIDENTE NUCLEAR DO JAPÃO
Funcionamento de uma usina nuclear
Aspectos de segurança
Geração de energia elétrica
Movimentação de turbina
Variação de fluxo magnético em
Térmoelétrica
Hidroelétrica
http://fisicaemseislicoes.blogspot.com
Gasto de elemento combustível
Variação de fluxo magnético em
espiras
Combustível
Fissão induzida por neutron
Urânio (235/238) ou Plutônio (239)
Partículas pesadas + neutrons (>1)
(reação em cadeia)
Controle
Limitar número fissões
Absorção de neutros (barras de Cd)
Fissão induzida por neutron
Moderador
Melhorar eficiência
Ajustar energia neutrons
Urânio (235) – neutrons térmicos
Água ou grafite (baixar energia)
Nuclear power plants in commercial operation
Reactor type Main Countries Num GWe Fuel Coolant Moderator
Pressurised Water Reactor (PWR)
US, France, Japan, Russia,
China 265 251.6 enriched UO2 water water
Boiling Water Reactor (BWR) US, Japan, Sweden 94 86.4 enriched UO2 water water Pressurised Heavy Water Reactor 'CANDU'
(PHWR) Canada 44 24.3 natural UO2 heavy water
heavy water
Gas-cooled Reactor (AGR & Magnox) UK 18 10.8
natural U (metal), enriched UO2
CO2 graphite
Light Water Graphite Reactor (RBMK) Russia 12 12.3 enriched UO2 water graphite Fast Neutron Reactor (FBR) Japan, Russia 2 1.0 PuO2and UO2 sodiumliquid none
Other Russia 4 0.05 enriched UO2 water graphite
Name Type Capacity (MWe), net/gross Status
Angra-1 PWR 626MWe Net CNAA-Central Commercial Operation 1985-01
Angra-2 PWR 1275MWe Net CNAA-Central Commercial Operation 2001-02
Usinas no Brasil
wikipedia
Research Reactors
•São Paulo– IEA-R1 –Pool-type reactor, 5MW – IPEN-Instituto de Pesquisas Energéticas e
Nucleares, São Paulo, SP (criticality 1957-09-16)
•Belo Horizonte– IPR-R1 – TRIGAMark I, 250 kW - CDTN-Centro de Desenvolvimento de Tecnologia
Nuclear,Belo Horizonte, MG (criticality 1960-11-06)
•Rio de Janeiro– ARGONAUTA –Argonaut class reactor, 100 kW – IEN-Instituto de Engenharia
Nuclear,Rio de Janeiro, RJ (criticality 1965-02-20)
•São Paulo– IPEN/MB-01 –Critical assembly, 0.1 kW – IPEN-Instituto de Pesquisas Energéticas e
Aspectos de segurança
Usinas nucleares usam uma proporção de 3 - 4% de U-235 e 96 - 97%
de U-238. Reatores nucleares para pesquisa, como os do Instituto de
Pesquisas Energéticas e Nucleares (
Ipen
), usam cerca de 20% de
U-235. Já as bombas atômicas usam 90% de U-U-235. O urânio natural
possui somente 0,7% de U-235.
When a meltdown occurs in a reactor, the reactor "melts". That is, the
temperature rises in the core so much that the fuel rods actually turn
temperature rises in the core so much that the fuel rods actually turn
to liquid, like ice turns into water when heated. If the core continued to
heat, the reactor would get so hot that the steel walls of the core would
also melt. In a complete reactor meltdown, the extremely hot (about
2700 Celsius) molten uranium fuel rods would melt through the bottom
of the reactor and actually sink about 50 feet into the earth beneath the
power plant. The molten uranium would react with groundwater,
producing large explosions of radioactive steam and debris that would
affect nearby towns and population centers.
Combustível acondicionado em discos cerâmicos
dentro de tubos de Zircônio (1400 C para danificar)
Fusão do elemento cerâmico + urânio (2800 C)
•
International Nuclear and
Radiological Event Scale (INES)
was introduced in 1990 by
the
International Atomic Energy
Agency
(IAEA) in order to
enable prompt communication
of
safety
significance
information in case of
nuclear
accidents
.
accidents
.
•
logarithmic
•
INES level of an incident is
assigned well after the incident
occurs
•
Radiation accidents
• Serious radiation accidents include:
• 1959, 1964, 1969 -Santa Susana Field Laboratory,Los Angeles,California. Partialmeltdowns. • September 1957 –Mayak nuclear wastestorage tank explosion atChelyabinsk. Two hundred plus
fatalities, believed to be a conservative estimate; 270,000 people were exposed to
dangerousradiationlevels. Over thirty small communities had been removed from Soviet maps between 1958 and 1991. (INES level 6).
• July 1961 –Soviet submarine K-19 accident. Eight fatalities and more than 30 people were
over-exposed to radiation.
• 1962 –Radiation accident in Mexico City, four fatalities.
• January 1969 –Lucens reactorin Switzerland undergoes partial core meltdown leading to massive
radioactive contamination of a cavern.
• 1979 -Church Rock uranium mill spillin New Mexico, USA. • March 1984 –Radiation accident in Morocco, eight fatalities.
• August 1985 –Soviet submarine K-431accident. Ten fatalities and 49 other people suffered radiation • August 1985 –Soviet submarine K-431accident. Ten fatalities and 49 other people suffered radiation
injuries.
• September 1987 –Goiania accident. Four fatalities and 249 other people received serious radiation
contamination.
• December 1990 –Radiotherapy accident in Zaragoza. Eleven fatalities and 27 other patients were
injured.
• April 1993 - accident at theTomsk-7 Reprocessing Complex, when a tank exploded while being
cleaned withnitric acid. The explosion released a cloud of radioactive gas. (INES level 4).
• 1996 –Radiotherapy accident in Costa Rica. Thirteen fatalities and 114 other patients received an
overdose of radiation.
• February 2000 - Three deaths and ten injuries resulted inSamut Prakarn when a radiation-therapy
unit was dismantled.
• April 2010 -Mayapuri radiological accident, India, one fatality. • March 2011-Fukushima I nuclear accidents, Japan (current event).
Dose Absorvida (D)
Massa
Energia
Dose
=
=
=
=
depositada
Gy =J/kg
Dose Equivalente (H
eq
) = D x Qualidade
(Sv) (Gy)
Tipo de radiação
Fator de Qualidade
Raios X, gama e elétrons
1
Raios X, gama e elétrons
1
Neutrons térmicos
2,3
Neutrons e prótons de energia
desconhecida
10
Partículas com carga unitária e
massa > 1 e energia desconhecida
10
Partículas alfa e partículas com
carga múltiplas
20
Fragmentos de fissão
20
Dose Efetiva (H
ef
) = ∑ H
eq
x W
i
Fatores Peso (W)
0,20 – gonadas
0,12 – médula óssea, pulmão,cólon, estomago
0,05 – bexiga, mama, fígado, esôfago, tireóide
0,01 – pele, superfícies ósseas
0,05 - outros
Limites
Trabalhadores População Dose Efetiva (Corpo int) 20 mSv/ano [1] 1 mSv/ano [2]
Dose Equivalente
Cristalino 150 mSv/ano 15 mSv/ano Pele 500 mSv/ano 150 mSv/ano Extremidades 500 mSv/ano 50 mSv/ano
