Industrial Radiography (IR) General overview. R. Berden

Transcription

1 Industrial Radiography (IR) General overview R. Berden

2 IR IN BELGIUM

3 What is industrial radiography (IR) Industrial radiography (IR) is a type of non-destructive testing (NDT) of welds using radiation from a radioactive source or an X-ray machine. Other NDT methods include visual, ultrasonic (TOFD), penetrant, acoustic emission, More radiation-related accidents occur in this industry than in any other.

4 Different possibilities in IR Use of: different radiation methods: X-ray equipment (panoramic, directional) Radioactive sources ( 192 Ir, 75 Se) in different installation types: fully shielded enclosure (failsafe) bunker fixed enclosure free on site

5 Different possibilities in IR Choice depending on: Available infrastructure in NDT company and/or client company; Equipment / materials to be checked; Demands client Applicable standards

6 Advantages and drawback X-ray equipment + No Power = no radiation Easy (electrical) connexion with safety equipment (interlocks, ambient dose meters, warning lamps) in a bunker (or on site) Better contrast Higher dose rates (several Gy s/min) Need of external power supply of hundreds of kv s Unsuitable for working on field especially with items of small dimensions or irregular shape The penetration ability of X-Ray s is limited to a few mm of steel due to low energy of emitted photons (up to 300KVp which means a mean energy about KeV ( MeV) Radioactive sources + Thicker wall thickness Easy deployment in installations Risk of blocked source (radiation exposure when safety equipment is not properly used, intervention team) Permanent risk of radiation (additional attention for transport and storage) (Mechanical) connexion between source container and safety equipment only possible with automatic wind-out (expensive, not always available)

7 Advantages and drawback Failsafe bunker + Optimal protection of operators and public Expensive Additional manipulations of equipment Difficult to achieve with source containers (only ambient dose meters) Not yet a clear legislation for implementation Fixed enclosure / site + A fixed enclosure reduces dose for operators in normal condition and for the public Protection of operators (and public for site work)

8 Radioactive sources Isotope Half-life Typical Thickness Range steel (m m) Typical activities TBq (Ci) Used In Belgium Iridium days ,5 (40) X Cobalt years ,7 (100) X Ytterbium days < 10 Thulium days < 10 Selenium days (80) X Caesium years 20-80

9 Radioactive sources Classification at least C (ISO 2919)

10 ISO 3999 Category II Class P exposure containers Exposure Device Outlet Port Source Guide Tubes Remote Control Crank

11 Old source containers Techops 660 Others: GammaMat S301, Teletron SU GammaMat TI (F)(F)

12 New source containers GammaMat TSI3 GammaMat SE

13 New source containers QSA SENTINEL 880 OSERIX DUAL 120

14 Portable X-ray equipment High voltage range (kv) Tube Current range (ma) 0,5 5 Beam Angle (º) 40 Inherent filtration (mm Be) 1 Settings 200kV/5mA: 300 msv/sec at 30 cm empirical data using radprocalculator Balteau Baltospot CERAM35

15 Main NDT-companies operating in Belgium Company Operators Source containers AIB VINCOTTE INTERNATIONAL SGS Apragaz Bytest 5 5 WMI 2 2 MISTRAS 8 3

16 Other NDT-companies operating in Belgium COPPENRATH D. SCMITT ZERSTÖRUNGFREIE MATERIALPRÜFUNG GMBH MATERIAAL METINGEN TESTGROEP Quality Inspection Services STORK Technical Services

17 Regulations Belgian Regulation (Royal Decree) is very general and is not written specifically for industrial radiography. 1 st renewal of licenses in December 2010 based on SSG-11: Radiation Safety in Industrial Radiography 2 nd renewal in April 2013 to implement the use of a radiation meter and active measurement.

18 License Conditions (1) Justification At least 2 operators (except for fixed installation in a shielded irradiation vault). Management system for safety Missions & responsibilities of all persons (including customers) Operational electronic dosimetry Accident prevention and safety culture (risk analysis, site audits, ) Notification to FANC of events significant for safety and/or radiation protection

19 License Conditions (2) Radiation protection training of personnel Approval by FANC Radiography equipment (ISO 3999) Site activities annual dose limit (300 µsv/an), dose rate limit (10µSv/h -> 40 µsv/h) Intervention team Temporary storage of the source on site Radiation meter and active measurement

20 Regulatory developments Mandatory use of failsafe bunkers Clients: shared responsibility Certification of operators by the FANC

21 Difficulty for legal framework Theory Reality

22 INCIDENTS

23 Incident Magotteaux April 2015 Magotteaux : metal casting company Use of a 60 Co (3,7 TBq) source for quality control of pieces New type of container SENTRY 330 (QSA Global) which replaces the previous GammaMat TK 100 container

24 Incident Magotteaux Fixed installation (in irradiation vault, approved by inspection organisation) Automated manipulation of the source

25 Incident Magotteaux 10 april 2015: significant event 10h30: source blocked outside the container 15h22: Notification AFCN No exposure of operators. Several attempts to retrieve the source under supervision of inspection organisation and with the help of manufacturer Decoupling of automated system and manual system (remote handling) Not successful

26 Incident Magotteaux 13 april2015: Visualisation by means of endoscopic camera to find the exact location of the source. Additional attempts to remotely retrieve the source were not successful Further interventions not allowed by inspection organisation and FANC

27 Incident Magotteaux Need to establish a unique protocol to retrieve the source Intervention team : licensee and inspection organisation, QSA Global, Military, Civil Protection, FANC Use of military grade robot, used for mine clearing purposes Cold test on real size mock-up of irradiation vault

28 Mock-up of inner part of irradiation vault

29 Robot moving the container that will house the source - Container needed to be modified

30 Cold testing of robot manipulations

31 Positioning of the cable by the robot

32 Source entered in container safely interlocked success of the operation

33 Cold testing Image of on-board camera

34 Dose cartography with shielded doors open: 5 µsv/h

35 Preparation of retrieval

36 Intervention Removal of command cable of source holder: source intact and safely retrieved and stored in Techops 680

37 Human error: ejection hoses not properly connected (Images from irradiation vault)

38 Put back into service on 18 may 2015 after extensive testing (including cold tests). Reparation of cable and micro balls

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43 Incidents October 2014: Exposure of members of public (airport handlers) during radiography (bad coordination of work programme) October 2014: Failure of source retraction 192 Ir (TSI3) November 2014: Exposure of 4 members of public (bad coordination of work programme) January 2015: Operators declare difficulties in source retraction of DUAL 60 source container March 2015: Wrong manipulation during source transfer of 192 Ir source from DUAL 60 to UKI4 container, leading to exposure of a worker and a FANC inspector (INES 1) March 2015: Legal dose limit exceeded during radiography (65 msv registered on dosimeter, INES 2)

44 SITE INSPECTIONS

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63 Difficult sector Low-skilled operators (secondary school) Clients of NDT company IR = essential quality assurance in work flow Pressure by client on operators: execute work in between, at night or after hours Last minute changes Responsibility: link FPS ELS No clear legislation for bunkers: postpone investments

64 Difficult sector Competition between companies (foreign companies) Habituation to radiation risk (Multiple) subcontractors Interference with other radioactive measurements Work at heights (heavy containers) Irregular working times Language