Ivan P. Salati de Almeida

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Seniors 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
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The accident of Goiania - Brazil
Distances
Goiania-Brasilia173 km
Goiania-S.Paulo937 km
Goiania-R.Janeiro810 km
Brasilia
Goiania
R.Janeiro
S.Paulo
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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

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Impacted area
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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

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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.

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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

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Monitoring people
Olympic Stadium (112,800 persons monitored)
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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

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Main contamination foci
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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

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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

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The main piece of the source
0.4 Sv/h at 1m (120 Ci) Emergency shielding
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Decontamination work
Site isolated for decontamination
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Decontamination work

• 57th Street
• Place where the source was opened

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Decontamination work

• House and land contaminated
• Dose rate 1,1 Gy/h at 1m

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Decontamination work
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Decontamination work
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Decontamination work
equipment head
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Decontamination work

• Assignment of contaminated areas
• Criteria (0.5 ?Sv/h)

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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

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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
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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

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Interim storage of waste
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Interim storage of waste
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Interim storage of waste
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Final Repository
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Final Repository

• Deposit 1 (common waste lt 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

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Final Repository
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Final Repository
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Final Repository
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Final Repository
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Final Repository
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Final Repository
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Final Repository

• Regional Center for Nuclear Sciences Information
  Building

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The end
Thank you