Technical Meeting on Radiation Safety in Industrial Radiography IAEA – Vienna 23 - 27 June 2014

1. Technical Meeting on Radiation Safety in Industrial Radiography IAEA – Vienna 23 - 27 June 2014 Brazilian Industrial Radiography Accident: Reconstructive Dosimetry and Lessons Learned Dr. Francisco Cesar Augusto Da Silva Instituto de Radioproteção e Dosimetria - IRD/CNEN Brasil

2. Brazilian Overview Nuclear and Radioactive Installations Nuclear Installations Nuclear Power Plant: 2 Nuclear Research Reator: 4 Nuclear Mining and Milling: 2 Fuel Cycle Industrial Complex : 2 units Navy Industrial Complex: 1 unit CNEN Research Institutes: 5 units (radioisotopes production, cyclotron accelerator; industrial irradiator, gammagraphy source production, metrology laboratory,...) Medical X Ray Devices: 100000 Radioactive Installations: 1574 Industry Area: 635 Medical Area - Radiotherapy and Nuclear Medicine: 680 Research: 228 Service: 31

3. Brazilian Overview Approved Laboratories 165000 Radiation Workers 12 Individual Monitoring Laboratories (Film Badge, TLD and OSL) 7 Calibration of Equipment Laboratories (1 SSDL) Medical Area: 75% Industry, Research & Other Areas: 25% Reference: CASEC/IRD/CNEN June 2014

4. Brazilian Overview Industrial Radiography • 92 Installations (Companies) • 276 Radiation Protection Officers • 1700 Radiographers (Operators) • 300 Gamma Devices with sources of 192Ir, 75Se, 60Co • 200 Daily On-site Radiographies Reference: CNEN´s Database – June 2014

5. Brazilian Overview CNEN Regulations • General Regulations: • NN-3.01-2014: BASIC SAFETY STANDARDS FOR RADIATION PROTECTION • NE-5.01-1988: SAFE TRANSPORT OF RADIOACTIVE MATERIAL CNEN National Commission of Nuclear Energy Brazilian Regulatory Authority • Specifics Regulations applied to Industrial Radiography: • Res 166-2014: Licensing Requirements for Radioactive Installations • NN-6.04-2013: Safety and Radiation Protection Requirements for Industrial Radiography Services • NE-3.02-1988: Requirements to Radiation Protection Services • NN-7.01-2013: Certification of Qualification for Radiation Protection Officer

6. Relevant Radiological Accidents Events with severe injuries 1997 -192Ir - 1.62 TBq (43Ci) Brazilian data include 5 serious radiological accidents affecting 7 radiation workers and 19 members of the public, resulting in the development of the Cutaneous Radiation Syndrome in hands and fingers. Wrong emergency rescue procedure: a trainee operator held the source holder with his the hand. 1985 -192Ir - 0.88 TBq (23Ci) A device was stolen from the transport vehicle and a truck driver found it. The radioactive source was removed and handled by members of the public. 2000 – 60Co - 2.11 TBq (57Ci) Due to a procedure failure, during routine maintenance work of a cobalt device, an operator kept his left hand very close to the radioactive source, during approximately 30 seconds. Reference: GADE/IRD

7. The Radiological Accident – May 2000 An industrial gamma radiographer was performing routine exposures with a 60Co Gammamat apparatus (model TK100, Isotopen-Technik Dr. Sauerwein) containing a 2.11 TBq (57 Ci) source. The operator was not bearing a personal monitor with alarm, and did no carry a survey meter. At the end of the tasks, when he tried to detach the guide tube from the exposure container - unaware that the source was not in the secured position - he kept his left hand very close to the radioactive source, for approximately 30 seconds. Noticing that it was impossible to detach the guide tube from the device, area monitoring was conducted, which showed that indeed the source was not in the secured position. The source was jammed in the internal tube near the guide tube.

8. Reconstructive Dosimetry Methods The effective and absorbed dose estimations of the Brazilian accident were performed using the following methods: Physical Method by film badge individual monitor and a simulator of a left hand with thermoluminescent dosimeters; Computational Methodby a Brazilian Monte Carlo calculation code, named “Visual Monte Carlo –VMC”, with human body voxel simulator Biological Dosimetry Method by cytogenetic analysis Clinical Observation of the signs of the lesion, particularly in the fingers and hand with radiation-induced necrosis.

9. Computational Simulation to Hand Dose Physical and Computacional Methods The dose reconstruction used for assessment of the distribution of doses on the worker’s left hand and organs were made using two methods: physical and computational techniques. For the first technique a physical hand simulator was built and it was also used the Alderson Rando phantom for organs doses. The computational method was performed using microcomputer software for external dose calculations, named ‘Visual Monte-Carlo - VMC’, together with a hand voxel simulator and Alderson Rando phantom. The values obtained through both methods for the distribution of absorbed doses on the operator’s left hand and organs doses were compared. Computational Simulation to Organ Dose

10. Results of Dose Estimations • Effective dose of 88.1 mSv using film badge individual monitor. • Effective dose of 60 mGy based on observation of none dicentrics observed at one thousand cells scored using the cytogenetic analysis. • Absorbed doses of 7.41 Gy and 17.56 Gy in the thumb and index fingers using a left hand physical simulator. • Absorbed doses between 10 Gy and 20 Gy in the thumb and index fingers based on the clinical observation of oedema and erythema in operator`s hands after 8 days; appearance of blisters on his left hand, mainly on the thumb and index finger after 21 days and dry desquamation on both hands after 23 days. • Absorbed doses of 7.80 Gy and 15.90 Gy in the thumb and index fingers using Visual Monte Carlo computational dosimetry method Absorbed doses (mGy)

11. Main Causes Operator Consequences • The radioactive source had stuck inside the exposure container, but not in the secured position due to corrosion inside the container and poor maintenance of the equipment. • The operator was not carrying his personal alarm. • The operator did not perform the proper and necessary radiation monitoring of the gamma device with a portable radiation monitor. • The operator failed to follow the safety procedures. Erythema, oedema and blisters on the operator’s hands (Day 30). Regulatory Authority Enforcement • Formal reprimand to the Company’s Director. • Temporary suspension of the facility operation. • Restriction of using of the 60Co gamma device. • Permanent removal of the operator from radiation job.

12. Lessons Learned • To assess periodically the gamma device internal channel with an industrial borescope. • To perform periodically the smear test inside the gamma device internal channel. • To provide the use of individual monitor with audible and vibrating alarms for all operators permanently. • To maintain continuous education and training in radiation protection and safety in industrial radiography.

13. Lessons Learned Education and Training in Radiation Protection and Safety in Industrial Radiography

14. Lessons Learned Education and Training in Radiation Protection and Safety in Industrial Radiography

15. Lessons Learned Education and Training in Radiation Protection and Safety in Industrial Radiography Evaluation of Eye Lens Doses on Industrial Gamma Radiography Workers using Monte Carlo Method Portable Gamma Devices Radioactive Source: Iridium-192 – gamma radiation Activity Max. 3.7 TBq

16. Lessons Learned Education and Training in Radiation Protection and Safety in Industrial Radiography Safety Evaluation of Gamma Radiography Devices Portable Gamma Devices Radioactive Source: Iridium-192 – gamma radiation Activity Max. 3.7 TBq In Industrial Radiography were recorded more than 40 radiological accidents involving 37 workers, 110 members of public and 12 deaths, around the world. Industrial radiography is used throughout the world to examine the structural integrity of materials in a non-destructive manner.

17. ANALYSIS OF RADIOLOGICAL ANALYSIS OF RADIOLOGICAL ACCIDENTS IN INDUSTRIAL ACCIDENTS IN INDUSTRIAL RADIOGRAPHY RADIOGRAPHY LESSONS LESSONS IDENTIFIED IDENTIFIED LESSONS LESSONS LESSONS LESSONS LEARNED LEARNED Lessons Learned Education and Training in Radiation Protection and Safety in Industrial Radiography

18. Main Objectives: • To investigate all radiation overexposure cases recorded by personnel dosimetry. • To evaluate the worker dose and, if necessary, to give information for medical actions. • To find out the real causes of the event and to emit recommendations to avoid other radiation overexposure cases. • To modify or to ratify the exposure recorded on the personnel monitoring register. • To publish scientific information about all radiation overexposure cases. • To maintain a database of radiation overexposure cases. Radiation Overexposure Analysis Group Main Activities: • Technical and scientific analysis of the accident. • Dose investigation and accident reconstruction • Dose calculation • Cytogenetic dosimetry • Technical report with recommendations to avoid other radiation overexposure cases From 1985 to 2012, 560 persons were investigated of having been overexposed.

19. Thanks Francisco Cesar Augusto Da Silva dasilva@ird.gov.br - Brasil