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Ivan P. Salati de Almeida
Director 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 km
Goiania-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 monitors
450 dosimetric pens
Professionals involved:
250 technical staff
300 support staff
Time
First period: September 29th to December 24th 1987
Second 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
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
Regional Center for Nuclear Sciences Information Building
Final Repository
The end
Thank you