leak test with sealed source example.pptx

LEAK LEAK TEST TEST OF OF SEALED SEALED SOURCES SOURCES MOHD FAZLIE ABDUL RASHID Health Physics Group Radiation Safety & Health Division Malaysian Nuclear Agency [email protected] DEFINITION DEFINITION SEALED SOURCE  Any radioactive material permanently sealed in inactive container or capsule, b...

LEAK LEAK TEST TEST OF OF SEALED SEALED SOURCES SOURCES MOHD FAZLIE ABDUL RASHID Health Physics Group Radiation Safety & Health Division Malaysian Nuclear Agency [email protected] DEFINITION DEFINITION SEALED SOURCE  Any radioactive material permanently sealed in inactive container or capsule, bonded wholly within inactive material, so as to prevent dispersion of radioactive substance during routine use OR  Sealed radionuclide or sealed source is radiation source consisting of any radioactive material, nuclear material or prescribed substance firmly incorporated in solid and effectively inactive material, or sealed in an inactive container of sufficient strength to prevent, under normal conditions of use, any dispersion of its contents. Radioactive Sealed Sources Sealed source form include: Plated sources Capsules Activated metal Plated Sources In this form, the radioactive material coats a disk or planchette. This coating may be covered, depending upon the type of radiation, by mylar, aluminum, steel, or plastic. Capsules In this form, a capsule usually made of metal surrounds the radioactive material. These sources are often placed onto the end of metal or plastic handling rods. Another example of a capsule is when a mixture of radioactive compounds is placed into a container and welded or sealed closed. Co-60 Radiotherapy Device Co-60 Industrial Radiography Activated Metal In this form, a metal wire or foil has been exposed to a neutron flux to irradiate the metal and create a radioactive isotope from the original material. This form of sealed source may have a plastic or epoxy coating to protect the activated metal. Radium-226 Radioactive Needles for Brachytherapy Nuclear Gauge WHAT WHAT IS IS LEAK LEAK TEST TEST Physical test conducted on sealed source to ensure integrity of capsule by collecting leakage activity from the source ASPECTS OF LEAK TEST 1. 2. 3. 4. Authorized personnel Collect activity leaked out ALLOWABLE LEAKED ACTIVITY < 5 nci (185 bq) Cease use if leak is confirmed REQUIREMENTS FOR LEAK TEST Each sealed source, except as qualified exemption specified leakage test shall be performed :  when used continuously, leakage tests shall be conducted at least once a year;  when the sealed source or shielding (DU) stored more than a year, a leak test must be done before the sealed source reused or transferred;  when the sealed source or shielding (DU) stored and handled, leakage test shall be conducted once every two (2) years;  when a fault occurs on shielding (DU) or radioactive sources, leakage tests shall be performed immediately before the operation or the transfer carried out; and EXEMPTION FOR LEAK TEST Sealed sources which are exempted from leaktest: i. Tritium (3H) gas lamp including tritium with activity < 74 GBq ii. Sealed source with half life 30 days or less iii. Sealed source in form of gas eg. Krypton-90 (Kr90) iv. Sealed source of beta or gamma emitter with activity 3.7 MBq or less v. Sealed source of alpha or neutron emitter with activity 0.37 MBq or less CAUSE OF LEAKAGE 1. CHEMICAL FACTORS E.g : - Corrosion, leaching 2. PHYSICAL FACTORS E.g : - Atmosphere conditions, stress, pressure 3. MECHANICAL FACTORS E.g : Friction, vibration PRECAUTIONS    Not to damage thin window and capsule seal mechanically Not to use corrosive material Not to overexpose to worker and public METHOD OF LEAK TEST 1. Visual inspection  Physical damages  Cracks  Rupture, etc 2. Technical evaluation  Radioactive method  Non radioactive method LEAK LEAK TEST TEST METHOD METHOD RADIOACTIVE METHOD NON RADIOACTIVE METHOD 1. Wipe (Smear) test 1. Vacuum bubble test 2. Dry wipe test 2. Hot-liquid bubble 3. Immersion test 4. Bioling immersion test 3. Gas pressurisation bubble test 5. Gases emanation test 4. Helium test (For Ra-226) 5. Helium pressurisation 6. Liquid scintillant test emanatic test (For Ra226) 6. Water pressurisation test Potential Location  Swabs / wipes should be done at locations of potential leak or contamination. Among these locations arei. welded areas (connection) at source container ii. areas of cracks or physical damage; iii. window area of the source iv. any area with potential of leakage or contamination  For radiation equipment with DU shielding ie. gamma projector  S tube configuration shall be examined using the methods adopted by the AELB to ensure no DU contamination. Potential Location  A cotton swab, injection prep pad, filter paper, or tissue paper is suitable. Samples should be taken as follows: a) For small sealed sources,  wipe the entire accessible surface area. Pay particular attention to seams and joints. However, do not wipe the port of beta applicators. b) For larger sealed sources and devices (instrument calibrator, bone mineral analyzer source),  wipe near the radiation port and on the activating mechanism. c) For teletheraphy machines,  wipe with the source in the off position. Wipe the area near the shutter mechanism, Also wipe the primary and secondary collimators and trimmers. d) Radium sources  should also be checked for radon leakage. This can be WIPE (SMEAR) TEST (WET) 2. MOIST A SWAB OR SUITABLE MATERIAL OF HIGH ABSORBENT CAPACITY WITH A DISTILLED WATER 3. WIPE THE NEAREST ACCESSIBLE POINT TO THE SEALED SOURCE WHERE CONTAMINATION MIGHT ACCUMULATE THOROUGHLY WITH THE MOISTED SWAB 4. MEASURE USING SURVEY METER 5. LABEL THE SWAB AND KEEP INSIDE THE LEAK TEST KIT. 6. BRING BACK FOR COUNTING USING GROSS BETA GAMMA COUNTING SYSTEM Leak or not?? Leak if: ≥ 185 Bq @ 5 nCi *Cease use if leak is confirmed Record Keeping 3 years THANK YOU