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Ivan P. Salati de Almeida Director of Radiation Protection and Nuclear Safety

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.

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Ivan P. Salati de Almeida Director of Radiation Protection and Nuclear Safety

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  1. 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

  2. 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

  3. 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

  4. Impacted area

  5. 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

  6. 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.

  7. 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

  8. Monitoring people Olympic Stadium (112,800 persons monitored)

  9. 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

  10. Main contamination foci

  11. 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

  12. 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 29thto December 24th 1987 • Second period: January to end of March 1988

  13. The main piece of the source 0.4 Sv/h at 1m (~120 Ci) Emergency shielding

  14. Decontamination work Site isolated for decontamination

  15. Decontamination work • 57th Street • Place where the source was opened

  16. Decontamination work • House and land contaminated • Dose rate 1,1 Gy/h at 1m

  17. Decontamination work

  18. Decontamination work

  19. Decontamination work equipment head

  20. Decontamination work • Assignment of contaminated areas • Criteria (0.5 Sv/h)

  21. 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

  22. 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

  23. 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

  24. Interim storage of waste

  25. Interim storage of waste

  26. Interim storage of waste

  27. Final Repository

  28. 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

  29. Final Repository

  30. Final Repository

  31. Final Repository

  32. Final Repository

  33. Final Repository

  34. Final Repository

  35. Final Repository • Regional Center for Nuclear Sciences Information Building

  36. The end Thank you

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