ivan p. salati de almeida director of radiation protection and nuclear safety
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Ivan P. Salati de AlmeidaDirector of Radiation Protection and Nuclear Safety
Brazilian Nuclear Energy National Commission- CNEN
September 2012
Small Scale Post-Accident Remediation
Senior’s Regulator Meeting
Session II - Specific Challenges in Implementing Remediation
BrasiliaGoiania
The accident of Goiania - Brazil
R.Janeiro
S.Paulo
Goiania-Brasilia=173 km
Goiania-S.Paulo=937 kmGoiania-R.Janeiro=810 km
Distances
Location
• City: Goiania (Capital of the State of Goias)
• Population: ~1.000.000 inhabitants (at the time of
the accident)
• Teletherapy equipment with Cs-137 source
• Day of the accident: September 13th,1987
Impacted area
CS-137 source characteristics
• Source activity (Sept/87): 1375 Ci (50.9 TBq)
• Chemical composition: caesium chloride (CsCl)
• Physical condition: compacted powder
• Mass CsCl: 93 g
• Mass Cs-137: 19.3 g
Chronology• September 10th to 13th,1987: part of a teletherapy
equipment with a caesium-137 source was removed from an abandoned building and opened, breaching the caesium capsule.
• September 13th to 28th: the Cs-137 was distributed to other people and was spread through other places in the city. Several people were hospitalized with symptoms of high doses irradiation.
• September 28th to 29th: the accident was confirmed by a medical physicist and first actions were taken by local authorities.
• September 29th to 30th: CNEN was notified and sent experts to Goiania.
Main issues to be dealt with in the accident
• People monitoring and assessment of environmental
contamination
•Medical care for victims (irradiated and contaminated)
•Re-establishment of the source control
•Decontamination of the places
•Interim storage for the waste generated
•Definition and construction of a repository
Monitoring people
Olympic Stadium (112,800 persons monitored)
Data from the accident
Monitored persons = 112,800 Contaminated persons = 271
• clothes and shoes = 120• body contamination = 151
People with deterministic hazards = 28 Victims hospitalized= 20 Syndrome of acute radiation = 8 Hazards in bone marrow = 4 Deaths = 4
Main contamination foci
Data from the accident
7 main contaminated places
42 additional contaminated places
85 contaminated houses; 7 demolished
50 vehicles decontaminated
Aerial survey with helicopter equipped with
radiation detector (67 km2 monitored)
Terrestrial survey with a car equipped with radiation
detector
Data from the accident Equipment: 55 dose rate meters,
23 contamination monitors450 dosimetric pens
Professionals involved:250 technical staff300 support staff
TimeFirst period: September 29th to December 24th 1987Second period: January to end of March 1988
The main piece of the source
0.4 Sv/h at 1m (~120 Ci)Emergency shielding
Site isolated for decontamination
Decontamination work
57th Street Place where the source was
opened
Decontamination work
House and land contaminated Dose rate 1,1 Gy/h at 1m
Decontamination work
Decontamination work
Decontamination work
equipment equipment headhead
Decontamination work
Assignment of contaminated areas
Criteria (0.5 Sv/h)
Decontamination work
– 5 mSv first year
– 1 mSv/y dose for the whole life
– Critical path for exposition:
• Gama exposition inside home
• Gama exposition outside home
• Internal dose due to inalation and ingestion of fruits,
vegetables, domestic animals
Criteria for decontamination
Remediation actions
• Part of the soil was removed and covered with concrete
• Part of the soil was removed and substituted with non contaminated soil
Contaminated trees were cut
down
Waste resulted from the accident
• 3,500 m3 (6,000 Ton.)
• 1,343 metallic boxes
• 4,223 drums (200 liter each)
• 10 maritime containers
• 8 Concrete cylinders VBA type
Interim storage of waste
Interim storage of waste
Interim storage of waste
Final Repository
• Deposit 1 (common waste < 90 years)Store about 40% of waste (very low activity).
• Deposit 2 ( 300 years)
• Dimensions: – Wall thickness: 25 cm– Basis surface distance from the soil level: 80 cm– Length: 54 m– Width: 14 m– Height: 4 m
Final Repository
Final Repository
Final Repository
Final Repository
Final Repository
Final Repository
Final Repository
Regional Center for Nuclear Sciences Information Building
Final Repository
The end
Thank you
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