Senior’s Regulator Meeting
Session II - Specific Challenges in
Implementing Remediation
Small Scale Post-Accident
Remediation
Ivan P. Salati de Almeida
Director of Radiation Protection and Nuclear Safety
Brazilian Nuclear Energy National Commission- CNEN
September 2012
The accident of Goiania - Brazil
Distances
Goiania-Brasilia=173 km
Goiania-S.Paulo=937 km
Goiania-R.Janeiro=810 km
Brasilia
Goiania
R.Janeiro
S.Paulo
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
Decontamination work
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
head
Decontamination work


Assignment of
contaminated areas
Criteria (0.5 Sv/h)
Criteria for decontamination
– 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
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
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
The end
Thank you