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