Radiation Safety Procedure

RADIATION SAFETY PROCEDURE IONISING RADIATION

Number:SOGEC-RT-BH-01 Issue : 0 Rev. : 0

SOGEC - NDT

Radiation Safety Procedure

Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad

Issue Date 13/07/2010

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Table of Contents Table of Contents..............................................................................................................2 1. Policy....................................................................................................................................3 Scope.........................................................................................................................................4 .................................................................................................................................................4 References.................................................................................................................................4 Radiological Units....................................................................................................................4 Personnel...................................................................................................................................5 Radiation Protection Supervisor (RPS)................................................................................5 Authorized Persons:..............................................................................................................5 Classified Persons:................................................................................................................6 Non Classified Persons:........................................................................................................6 1.Personnel Monitoring............................................................................................................7 Medical Examination............................................................................................................7 Monitoring............................................................................................................................7 Incident Reporting................................................................................................................7 Records.................................................................................................................................7 Equipment Inspection...............................................................................................................8 General..................................................................................................................................8 In Correct Delivery...............................................................................................................8 On Arrival at Work Location................................................................................................8 Daily Checks.........................................................................................................................8 Storage of Sealed Sources ....................................................................................................8 Control of Sealed Sources ....................................................................................................9 Loss / Mislaid of Sealed Sources .........................................................................................9 Radiation Operations................................................................................................................9 Site Radiography.....................................................................................................................11 Transportation of Sealed Sources: .........................................................................................12 General................................................................................................................................12 Road Transportation...........................................................................................................12 Annexure: 1.........................................................................................................................12 Introduction.....................................................................................................................12 Source struck out side of its projector............................................................................13 Loss / stolen of source....................................................................................................13 Vehicle Accident.............................................................................................................14 Equipment.......................................................................................................................14 Medical checks for personnel involved in emergency....................................................14 Calculating Intensity with the Inverse Square Law........................................................15



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1. Policy The SOGEC will ensure, as far as is reasonably practicable, the health and safe ty of members of the public, of its employees and of contractors working on the prem ises who may be exposed to the hazards arising from the use of ionizing radiations (e.g . xray, gamma rays etc .). The SOGEC is committed to a policy of keeping exposures to ionizing radiation as low as reasonably practicable, social and economic factors being take n into account. The SOGEC will maintain a Radiation Protection management structure to implement radiation safety requirements. Radiation Protection Supervisors will be appointed to cover each department using ionizing radiation (unless exempted by the Regulations) respectively to enable work with radiation to be carried out in a safe manner . All radiation facilities will be designed to meet the requirements of relevant Regulations, Codes of Practice and Guidance Notes and to ensure that doses to members of the public, and staff are below relevant nationally agreed dose constraints . Local Rules will be prepared to cover all procedures using ionizing radiation . The Rules will contain systems of work designed to minimize radiation doses to staff, and members of the public. Radiation doses to all radiographers work ing with ionizing radiation will be monitored by means of who le body dosimeters. Diagnostic medical examinations involving the use of ionizing radia tion will be carried within an overall management framework defined by Standard Operating Procedures and Protocols prepared by the SOGEC The minimizing of radiation doses to staff will be a prime factor in the selection and use of equipment. Quality Assurance tests will be carried out at regular intervals on all equipment involved in staff and public exposure with ionizing radiation. Staff working with ionizing radiation will be trained to a level commensurate with the work being performed and the degree of hazard involved and to satisfy legal requirements. The SOGEC will ensure that the radiation protection program is implemented and reviewed and that appropriate organizational arrangements are in place to facilitate it. Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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Scope This document is for the use of SOGEC personnel and its sub-contractors who are engaged in operations using ionizing radiation. The document covers the basic administrative, medical and operational requirements governing the control, storage, usage and transportation of radioactive sources.

References •

Radiation Safety for Site Radiography OCPCA 1986

•

Statutory Instrument No. 3232, Ionizing Radiation Regulations HMSO 1999

•

IAEA Regulations, Code of Practice Guides

Radiological Units •

Radioactivity :

S1 unit of radioactivity: Becquerel Old unit of radioactivity: Curie 1 Becquerel = 1 disintegration per second 1 Curie = 37 billion disintegrations per second 37 Giga Becquerel (GBq) = 1 Curie

•

Absorbed Dose:

S1 unit of Absorbed Dose: Gray(Gy) Old Unit of Absorbed Dose: Rad 1 Gray = 100 rads 1 Rad = l0 mGy

•

Dose Equivalent:

S1 unit of Dose Equivalent: Sievert(Sv) Old unit of Dose Equivalent: Rem 1 Sievert = 100 rem 1 Rem = 10 mSv

•

Radiation Output:

Gray Per Second (Gy/s) : 412.4 X 10 mR/hr Rontgen per hour (R/hr) : 2.425 ':::>JGy/s Units provided @ 1 Meter)



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Personnel Radiation Protection Supervisor (RPS) The SOGEC shall appoint in writing one or more suitably qualified employee(s) as Radiation Protection Supervisor (s). The above person shall be responsible for the supervision of all aspects of work involving the control, storage, use and transport of radioactive sources. His main role is to provide advice in the case of an emergency involving a radioactive source. His duties shall include overseeing safe work practices, dealing with the emergencies, investigation and reporting incidents. Name, location and telephone contact number of RPS shall be available at the work site where work involves ionizing radiation.

Authorized Persons: SOGEC shall appoint in writing, suitable qualified employees as authorized persons. Such persons shall be trained, qualified and certified minimum Level I in accordance with SOGEC Written practice for personnel qualification and certification in Non-destructive testing, meeting the requirements of SNT-TC1A of ASNT. The individual shall be fully conversant to undertake the following specific duties: 1. Safe use, control and transportation of Ionizing radiation Establishing the shielding for the protection of the personnel where ionizing radiation is present 2. Use of radiation equipment containing radioactive source, radiation survey instruments and personnel monitoring instruments Other duties specified by the Competent Person regarding all aspects of safety involved in ionizing radiation Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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Authorized personnel shall be registered by SOGEC with a recognized radiological body such as British National Radiological Protection Board that monitors the persons' radiation dose equivalent on a monthly basis with film badges. The personnel shall be provided with film badges for personnel monitoring when entering to the radiation area where the radiation level exceeds 7.5 micro Sv/hr(O.75mR/hr). They shall also be equipped with dosimeter.

Classified Persons: SOGEC shall appoint suitably trained employees to work as assistant under the guidance of authorized persons. Their duties require knowledge of safe operation of ionizing radiation sources, use radiation monitoring instruments, provide shielding and observe shielding parameters. They shall not undertake radiation source operation and other duties involving ionizing radiation unless so authorized in writing by SOGEC RPS.

Non Classified Persons: Persons who are not classified in the clause A through C, are called nonclassified persons, may be general public, contract personnel or others who are not connected with radiography activity. They are prohibited to involve in work or passage where ionizing radiation is present. They shall be excluded or away from restricted areas where the radiation level exceeds 7.5µSv (O.75mR/hr). Suitable warning signs and/or barriers shall be provided.

MAXIMUM PERMISSIBLE DOSE RATE: Considering the recommendations of the International Commission on radiological protection (ICRP), the maximum permissible dose rates for the personnel categories shall be as specified in Table I as follows: Category

msv/yr

(Rem/yr)

mSv/13wks (Rem/13wks)

RPSs

20

(2)

15

( 1.5 )

Authorized Persons

20

(2)

15

( 1.5 )

Classified Persons

20

(2)

15

( 1.5 )

Non Classified Persons

20

(2)

15

( 1.5 )



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1. Personnel Monitoring Medical Examination All Radiological personnel in the clause A through C shall undergo medical examination at once in a year, arranged by SOGEC. Whenever, the RPSs deems necessary or circumstances require, a special medical examination shall be arranged.

Monitoring All classified personnel shall be provided with a monitoring film badge as supplied by an approved organization like NRPB, UK/Nuclear Department @ Ministry of Health Kingdom of Bahrain. The film badge shall be worn on the body outside clothing and shall be replaced on every month and the used (exposed) film returned to the organization for assessment. The classified persons shall be responsible for the proper use and safe keeping on his badge and film.

Incident Reporting Any incident involving ionizing radiation where a dose rate in excess of that permitted is suspected shall be reported immediately with full details to the Radiation Protection Supervisor (RPS).

Records SOGEC shall maintain records of issue and return of monitoring film in respect of individual personnel together with doses registered on same and as reported by the laboratory by the each individual film. On occasion of employment, personnel shall receive a transfer record containing a summary of the individual radiation dose records.



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Equipment Inspection General The isotope shall not be examined physically. Instead, the isotope delivery note from the manufacturer and the decay chart are to be inspected to check that the isotope is of the correct type, size and source strength. The serial number on the decay chart shall match that of tag attached to the source container. An equipment check list shall accompany the radiographic source that provided a record of inspections carried out on the radiographic equipment.

In Correct Delivery If the incorrect source type, size or type has been delivered, this shall be immediately notified to the RPS for appropriate action.

On Arrival at Work Location The source and its accessories shall be checked for damage by radiographer upon arrival to work location and back.

Daily Checks Whenever the radiographic equipment is in use it shall be examined for external damage on a daily basis by the radiographer.

Storage of Sealed Sources The radiography source, when not in use, shall always be stored in a separate storage room/pit under lock and key. It shall never be left at site unattended. It is important to note that there shall not be any chance of water seepage into the room where the radiation source is stored. Radiation warning signs shall be conspicuously posted on the entrance door of the storage room. Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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The isotope storage room shall be suitably provided with adequate lighting and ventilation. The storage room shall preferably be located in an isolated area of minimum occupancy.

Control of Sealed Sources All gamma ray sources shall be of remote control type. Each projector shall have a unique number to facilitate record keeping in respect of movement, location and maintenance purposes. The sealed source shall also have unique number for record purposed and shall be accompanied by a decay chart at all times. All equipments shall be checked prior to use and shall be maintained in a clean and safe working conditions. All sealed sources shall be purchased from the approved suppliers and shall be supplied with test forms indicating that full testing has been performed in all respects. As the company operates within the maximum recommended working life of the nuclide (or Ir. 192 - 1 year) there is no statutory requirement for leak or swap test to be performed on the sealed sources or projectors in use.

Loss / Mislaid of Sealed Sources Daily movement of the sources shall be recorded in the store/site log book and shall be signed in and out by the responsible person as stated in clause A through C All Personnel should inform immediately to RPS if there is lost or misplace the sealed source. The RPS shall be investigating circumstances and then report to those with a need to know informed at all times.

Radiation Operations Radiation source shall only be operated by the personnel as stated clause A through C. The full length of the driving cable shall be made use of during panoramic exposures so that maximum possible distance is maintained between the radiation source and the operator. Larger the distance lesser will be the radiation source received. Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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The source shall always be operated from behind the projector thereby making use of the shielding provided by the body of the projector. The radiography personnel shall always position him as far away from the source as possible during exposures. In addition, he may make use of the shielding provided by huge objects usually present in the radiography area. All the exposures shall be planned in advance and executed in the minimum possible time. The shorter period of time the spent near the radiation source, the lesser the radiation dose received. Demarcation barrier tape (of a bright colour e.g. yellow or orange) and radiation signs in Arabic and English shall be used to cordon off unsafe areas where the radiation level is above 7.5 microSv/hr (0.75mR/hr). This area is called restricted area. The safe working distance shall be calculated based on the source Strength being used and the demarcation barriers shall be positioned accordingly prior to exposing the source. The position of the barrier may be altered after exposure subject to monitoring radiation level by survey meter. During operation, the radiation survey meter duly calibrated shall be used for monitoring the radiation level. The dose rate at the barrier of any radiation area shall not exceed 7.5micro Sv (0.75 mR/hr). When using gamma ray source, after termination of the each exposure, proper storage of the source inside the projector shall be verified with a radiation survey meter. Wherever practicable, collimators shall be used with isotope since shielded source is less hazardous and the primary beam of the Collimated exposure shall be directed towards areas of minimum occupancy. To prevent access to any radiation area, the area shall be closed with warning signs, barriers and flashing lights to warn hazard to radiation. During radiography operation, apart from film badge, the personnel shall be provided with quartz fiber dosimeter or audible alarm which gives instant assessment of the cumulative dose received. After completion of the radiography work, the projector and the source shall be securely locked to avoid accidental exposure due to opening of the shutter and also to avoid the source dropping out of the projector. Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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General Directorates for the Protection of Environment and Wild Life Bahrain shall be advised in writing of all radioactive material (Iridium 192) imported for use under contract to construction projects. The Following Information shall be in corporate. 1. Source Reference Code or type Identification 2. Radioactive Nuclide and Activity 3. Transport Index in designated Transport Shield 4. Purpose of Use 5. Date of Receipt 6. Storage Location

Site Radiography Upon receipt of written instruction to proceed to site for work involving the use of ionizing radiation, the authorized person shall adopt the following procedures: Proper radiography source shall be selected (gamma ray or X- ray) ensuring that the projector and source is correct in all respects. For safe working conditions, it ensure that all radiography safety accessories are fully operable, the accessories include radiation survey meter, dosimeter, audible alarm monitor, flash light with warning sign, barrier and collimator. Ensure that a tag displaying radiation warning sign and nature and strength of source is attached to the projector. All accessories required for the safe use of the radiographic source such as its handling tong shall be taken along with the projector. Radiography personnel shall report to the responsible person on site and shall briefly explain the requirements of safe operational area, highlighting the hazards associated with ionizing radiation. Warning signs, barriers and the flashing lights shall be established around the restricted area of exposure. If necessary, trial exposure shall be performed to monitor and adjust the barrier. In gamma radiography, the source shall be monitored both during exposure and retraction to ensure accurate location into the collimator and safe return to the projector. Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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During exposure, barriers shall be monitored particularly for any change in location in orientation of the source. After completion of the radiographic work, the gamma ray projector and source shall be monitored to ensure that the source has reached its safe place inside the projector and the projector is locked. If X-ray is used, The X-ray equipment shall be disconnected from its power source and the operating key removed from the control panel after completion of the radiography work. If any emergency situation arises involving ionizing radiation, the authorized personnel incharge shall observe the procedure stated in Annexure - I Radiation Emergency Procedure

Transportation of Sealed Sources: General Transpiration of sealed sources shall be in vehicles specifically licenses and registered by Bahrain Radiation Environment department. These vehicles should have warning notices front and rear indicating relevant information. The transportation shall be above mentioned clause A Classified personnel only.

Road Transportation The classified personnel only can transport sealed sources. The sealed sources container shall be monitored for safe lock and the proper sign to be labeled and proper records to be submitted to concern authority. The radiation warning sign boards should be displayed on the vehicle. The vehicle should not be left unattended by any person unless the vehicle must lock.

Annexure: 1 Introduction Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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This procedure defines a practical plan for handling an emergency situation that may arise involving ionized radiation from sealed sources other than those occurring under the normal circumstances. It describes the initial remedial action to be taken in different emergency situations such as loss damage to source, improper functioning or damage of container during site radiography resulting the source being left in an unknown / unshielded position.

Source struck out side of its projector When the source stuck outside the projector, the following procedure shall be followed. Stop all the operations and inform to the Radiation Protection Supervisor (RPS)/Site -In charge about the incident. Cordon-off the radiation area using survey meter and move the barrier and warning signs to the new restricted area where radiation level less than 7.5m Sv/hr. Try to retract the source or provide radiation shielding such as lead, steel sheets around the source if possible. If shielding is not available, dig a hole in the ground and put the pencil, Guide tube, camera etc., in the hole and cover it with earth. The Radiation Protection Supervisor (RPS/Site In-charge will access the nature of incident and plan for further action considering the source strength, shielding, Dose rates, location and other related factors.

Loss / stolen of source For any reason a sealed source is lost or mislaid, the following course of action shall be taken: Inform to the SOGEC Main Office /Site In-charge immediately about the incident. If the source is separated from the projector, search using survey meters from last known position of the lost source. Once the source been located, try to put the source in lead pot using manipulator rod considering the radiation lead. The lead pot with source shall place in the radiation pit. Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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Radiation Protection Supervisor (RPS)/Site In-charge shall decide the further course of action to reload in the projector. When a sealed source is believed to have been stolen, the Site Incharge/operator shall immediately inform to SOGEC Main Office, who will in turn inform to relevant authorities to investigate the incident.

Vehicle Accident Where a vehicle transporting a radioactive source is involve in an accident. The Civil defense authorities and the Police shall be informed immediately. Radiation level shall be monitored to ensure that the source is still inside the transport container or projector. The location of the source has been ascertained, the Authorized Person or RPS shall proceed to retrieve the source and container. All reports to be completed in accordance with local rules.

Equipment The following accessories should be used for the rescue operation. a) b) c) d) e) f) g) h) i) j) k) l)

Lead shot Handling tongs Recovery container Bolt cutter Hacksaw Screwdrivers Pliers Warning Signs Barrier tape Flash Lights Radiation Survey Meter Dosimeter and film badge

Medical checks for personnel involved in emergency An emergency involving a radiation hazard, the personal monitoring badges of the personnel involved shall be immediately sent to the appropriate radiological body (NRPB, Prepared and Reviewed by: Approved By SOGEC Radiation Safety Officer NDT Manager Vaidhiya G Ziad Mohdad


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U.K)/Ministry of Health Nuclide Dept. for assessments. The above person(s) shall go for a Medical Examination, to check whether there is excessively received dose or not. If there is any excess dosage found in the medical examination, they should consult a medical Practitioner and follow his advice.

Calculating Intensity with the Inverse Square Law Safe Distance for Unshielded Source Constant Out Put from Iridium 192 Source = 0.49 R/h @ 1 Meter (490mR/hr) Maximum Permissible Dose Rate: 0.75mR/hr I1 / I2 = D2 ² / D1 ² Where: I1 = Intensity 1 at D1 I2 = Intensity 2 at D2 (7. 5 μSv/hr) D1 = Distance 1 from source D2 = Distance 2 from source For 10 Ci Iridium 192 Source Using: 0.49 R/hr X 10 Ci = 4.9 R/hr 49000 mSv/7.5mSv = (D2)2/ (1m)' 49000mSv/7.5mSv = (D2)2 D2 = √6533 D2 = 80meter



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Radiation Safety Procedure

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