STANDARD OPERATING PROCEDURE:

Transcription

1 STANDARD OPERATING PROCEDURE: Handling sealed radiactive surces: alpha, beta and gamma Nte: T be undertaken nly by trained persnnel in cnjunctin with a site-specific risk assessment. Cntact yur state r territry radiatin regulatry authrity fr the interpretatin f regulatry matters. Fr cntact details see: 1. Intrductin It is desirable fr students t develp a respect fr the safe and prper use f radiatin. The mst cmmn radiactive materials used in schl science practical wrk are sealed radiactive surces. These surces are prvided as small sealed, circular clear plastic discs apprx. 2cm in diameter. Surces prvided t schls prduce inising radiatin and are generally supplied as an alpha-emitting americium-241 (Am-241) r plnium-210 (P-210), a beta-emitting strntium (Sr-90) and a gamma-emitting cbalt (C-60). The ptential fr harm frm these surces is very lw. The Australian Radiatin Prtectin and Nuclear Safety Agency (ARPANSA) is the Australian Gvernment's primary authrity n radiatin prtectin and nuclear safety. ARPANSA wrks with state and territry regulatrs t prmte natinal unifrmity f radiatin prtectin. Fr details f yur state/territry regulatr see 2. Cntext These instructins are fr the use f experienced science teachers, technicians and students ver the age f 16, wh are under the direct supervisin f a teacher. 3. Safety ntes All persns handling radiactive surces must be trained in their use. Class wrk with radiactive surces fr students in year 10 and under is restricted t teacher demnstratins. Students shuld be kept at least 2 metres away frm these surces during demnstratins. Fr detailed infrmatin regarding practice-specific guidance n best practice see the ARPANSA Safety Guide fr the Use f Radiatin in Schls (2012) see It is recmmended that persns handling sealed radiactive surces be familiar with this dcument and a printed hard cpy f this resurce is recmmended fr reference. Prtectin frm radiactive surces can be achieved by: reducing the time f expsure increasing the distance frm the surce increasing the shielding between persns and the surce. Page 1 f 10

2 Radiactive surces shuld therefre: be handled fr the shrtest time pssible (recmmended less than 2 minutes) never be picked up with fingers, but always with lng tngs be stred at least 2 metres (ignring walls) frm a place where anyne spends extended perids f time be stred within lead lining in a metal bx in a lcked secure area in the science department away frm highly flammable material See the supplementary infrmatin n strage f radiactive surces (see p5). 4. Regulatins, licences and permits The ARPANSA Safety Guide fr the Use f Radiatin in Schls (2012) sets ut the legal requirements fr schls t use inising radiatin surces. Fr detailed infrmatin regarding regulatins see the ARPANSA Safety Guide fr the Use f Radiatin in Schls (2012). T cmply with these regulatins yur schl will need: a respnsible persn wh ensures that all legal and safety requirements are met, usually the schl principal r the head f yur state/territry educatin department a schl radiatin supervisr wh will have respnsibility fr the safe strage, use and mnitring f radiatin surces. See the supplementary infrmatin n Radiatin supervisr appintment and respnsibilities (see p10) a set f lcal rules fr yur specific schl site that dcument where the radiatin surces are stred, where they can be used, wh can use them and where the use lg is kept. See the supplementary infrmatin n the use f sealed radiactive surces (see p6) t cntact yur state Radiatin Regulatry Authrity t ascertain whether yu need a radiactive licence. Cnsult the ARPANSA website ( fr the mst up t date list f regulatrs. 5. Equipment Radiactive surces, eg americium-241/plnium-210 (alpha); strntium-90 (beta); cbalt- 60 (gamma) Disc surce caesium-137 Disk surces in strage bx Geiger Müller (GM) Tube and Electrnic Cunter Lng frceps r tngs Varius radiactive absrptin materials such as paper, plastic, aluminium and lead in different thicknesses. Page 2 f 10

3 6. Operating prcedure 1. Fllw the lcal rules fr yur specific schl site. 2. Surces must nt be handled by persns with wunds n their hands 3. Refer t ARPANSA Safety Guide fr the Use f Radiatin in Schls (2012) page 22 fr cncerns regarding expectant mthers 4. Surces shuld nt be left unattended 5. Carry each surce in its strage cntainer and keep it there until it is required. D nt handle the cntainer fr lnger than necessary. 6. Use nly ne surce at a time in any ne investigatin. 7. Handle the surce with a lng tngs, which keep the fingers at least 10 cm away. 8. Keep the surce at least 20cm away frm yur eyes 9. Plug in GM-tube and electrnic cunter and perate reset switch t set cunter t zer. See manufacturer s instructins. 10. Measure backgrund radiatin away frm the surces fr at least 2 minutes. This is nrmal everyday radiatin which is always present. 11. Pick the surce up with the lng tngs. 12. Hld the GM-tube 5cm abve the surce and measure radiatin. 13. Place absrptin materials between the surce and the GM-tube t bserve the effects n the radiatin cunt. Alpha particles stpped by sheet f paper r surface layers f skin. Beta particles stpped by a few millimetres f aluminium r 1-2 centimetres f plastic. Gamma rays almst cmpletely stpped by abut 1 metre f cncrete r abut five centimetres f lead. Mst will pass thrugh the human bdy. 14. Cmplete the investigatin in the shrtest time pssible, cnsistent with gd results. 15. Return the surce t its nrmal cntainer immediately after cmpleting the investigatin. 16. The member f staff in charge is t check all surces fr signs f damage n return. 17. Immediately reprt t the member f staff in charge any event in which a surce cannt be accunted fr, is drpped r may have been damaged. 18. Always wash hands thrughly immediately after wrking with any radiactive surce. 7. Truble shting/emergencies Make sure that the Geiger cunter yu are using is set up and wrking prperly and will detect the radiatin being tested. Sme GM-tubes used in schls will nt detect alpha radiatin, as their end-windw is t thick. Am-241, which is rutinely used in schls, als emits a gamma particle as well as an alpha particle. The gamma particle will penetrate the thick-end windw f the GM-tube. The result frm the emissin f the gamma particle can Page 3 f 10

4 be interpreted as the emissin f an alpha particle if the GM tube nly respnds t beta and gamma radiatin. If any surce is drpped and damage t the surce is suspected, fllw the instructins in the supplementary infrmatin n cnducting an inspectin, wipe test and cntaminatin check (see p8) 8. Waste dispsal Radiactive surces can last fr many years depending upn their half-life. In the unlikely event that a surce is drpped and damaged r fails the wipe test, it will need t be dispsed f. See the supplementary infrmatin n dispsal f sealed radiactive surces (see p9) If yu are unsure f hw t dispse f yur radiactive surce, yu shuld cntact yur radiatin regulatry authrity fr advice abut dispsal 9. Related material Lcal rules fr yur specific schl site Risk assessment. Safety Guide fr the Use f Radiatin in Schls (2012). ARPANSA Part 1, Inising Radiatin : in particular see: Mdel Lcal Rules: Annex 5, pp Mdel Risk Assessment: Annex 4, pp Manufacturer s Instructins fr Electrnic Cunter and GM-Tube. (e.g. ) References: ARPANSA Safety Guide fr the Use f Radiatin in Schls (2012) CC BY NC 3.0 AU NSW Department f Educatin and Training (2013). Chemical Safety in Schls (CSIS) Sydney: NSW DET Intranet, (Lgin required. Accessed March 2014) Page 4 f 10

5 SUPPLEMENTARY INFORMATION: Strage f radiactive surces Radiactive surces must be stred t minimise the risk f expsure t peple in the surrunding area when nt in use, as well as t prvide a secure lcatin t reduce the risk f theft r vandalism. In cnsideratin f minimising the risk f expsure t peple in the surrunding area, the surces need t be shielded in lead t absrb the radiatin. Very ften they are delivered in a lead lined metal cntainer, which is a suitable ne fr radiactive surces t be stred. Sme f the gamma rays will still penetrate lead and fr this reasn the lcatin f the stre needs t be at least 2 metres in a straight line (ignring walls) frm a place where anyne spends extended perids f time. In cnsideratin f the pssibility f a fire, the surces need t be hused in a strng steel cntainer (such as a tl bx) that shuld be recgnisable after a fire r ther such majr incident and stred away frm flammable materials, s that firefighters d nt have t cntend with bth radiactive surces and flammables. This means that they shuld nt be stred in the chemical strerm, which will als reduce the likelihd f crrsin. Often they will be stred in the preparatin rm giving cnsideratin t relevant distances. In cnsideratin f the risk f theft r vandalism, the surces need t be in a secure stre, such as the steel cntainer being kept in a fixed, lcked cupbard r drawer, making sure there is n access via an adjacent cupbard r drawer, r in a lckable, steel cupbard that is securely fixed. Sme schls use wall safes fr this purpse. The key t this lcked stre shuld be unique and als kept secure. In rder t warn thers in the area f the presence f radiactive surces, the utside f the cntainers shuld be clearly labelled with the cntents and the internatinal radiatin symbl (als called a trefil sign) with the wrding radiactive materials. The utside f the cupbard, drawer, wall safe (and the separate metal cntainer, if used) shuld als be labelled with the trefil warning sign. The text is ptinal, but is useful fr thse unfamiliar with the symbl. Further signage f rm drs is nt required as it may draw unwanted attentin t their presence, hwever this can be a schl-based decisin. Summary fr strage f radiactive surces: Radiactive surces must be stred in a lead lined cntainer s that the utside f the cntainer is clearly labelled with Radiactive the cntents Materials a trefil warning sign and the wrding radiactive materials at least 2 metres in a straight line (ignring walls) frm a place where anyne spends extended perids f time in a strng steel cntainer away frm flammable materials and the chemical stre rm in a secure lcatin, with a unique key fr access Page 5 f 10

6 Use f sealed radiactive surces Rules must be established fr the use f radiactive surces t minimise the risk f expsure t peple using the surces. Recrds must be kept t ensure that the type and whereabuts f the surces is knwn at all times, and that inspectins, wipe tests, cntaminatin checks and dispsal f surces is dcumented. Rules Lcal rules shuld be written fr yur specific schl site. They are written t ensure that radiatin dses and risks f cntaminatin are minimised. Annex 4 f the Safety Guide fr the Use f Radiatin in Schls (2012) cntains example details f the mdel lcal rules that can be adapted t meet the needs f yur specific schl site: Lcal rules fr the use f radiactive surces must cntain: Name f schl Name f respnsible persn Name and cntact details f radiatin supervisr Lcatin f secure stre fr radiactive materials Labratries/rms where radiactive surces are used Lcatin f the fllwing dcumentatin Radiactive surce histry Use lg fr radiactive surces Mnitring recrd fr radiactive surces and stre Cntact details f yur Radiatin Regulatry Authrity Lcal rules fr science department staff which detail the safety prcedures and administrative requirements shuld be develped fr yur specific schl site: see example set in Safety Guide fr the Use f Radiatin in Schls (2012) pp Lcal rules fr staff and supervised students in years 11 and 12 see example set in Safety Guide fr the Use f Radiatin in Schls (2012) p 52 Recrd keeping: radiactive surce histry An inventry f all radiatin surces shuld be kept and the fllwing individual recrds need t be kept fr each radiactive surce: their purchase. a cpy f the purchase rder/invice/receipt the radiactive surce histry including, where pssible, the: unique name r reference number radinuclide r chemical name riginal activity delivery date, supplier and manufacturer. their use, inspectins, wipe tests and cntaminatin checks. their dispsal. Page 6 f 10

7 Recrd keeping: use lg fr radiactive surces Each time a radiactive surce is accessed it needs t be recrded in a use lg. The fllwing events cnstitute a use: a security check fr the presence f the surces (required at apprpriate intervals ). In mst schls where they are used ver a perid f a few days, and then nt fr anther year, a year wuld be an apprpriate interval. when used in classrm investigatins inspectins, wipe tests and cntaminatin checks (see supplementary infrmatin Cnducting an inspectin, wipe test and cntaminatin check, p8) Nte: Managers and staff in schls and clleges shuld take all pssible steps t ensure that lss f a radiatin surce cannt happen. Hwever, in the event that a surce is missing, the radiatin supervisr shuld check that it has nt been: returned t the wrng stre left inside the piece f equipment within which it was last used temprarily remved t anther area, r placed with waste fr dispsal. All incidents r accidents invlving radiatin surces, such as a situatin where a radiatin surce cannt be fund, must be reprted t the relevant radiatin regulatry authrity. In the first instance, this will usually be the Principal. If yu suspect that smene has remved the surce unlawfully frm the premises, the Principal, in cnsultatin with the radiatin regulatry authrity, will need t infrm the plice. Recrd keeping: mnitring recrd fr radiactive surces and stre Regular inspectins and wipe tests shuld be cnducted and the results entered int the use lg. Instructins fr cnducting an inspectin, wipe test and cntaminatin check are n p8. Regular inspectins, wipe tests and cntaminatin checks ensure that the mechanisms fr preventing dispersal f radiactive materials are functining as intended. Yu shuld carry ut an inspectin and wipe test nce a year n each surce kept in the radiactive materials stre, including stck bttles f radi chemicals if applicable. A simple recrd such as pass r fail in the use lg will be necessary fr each surce. Cntaminatin checks shuld be cnducted anywhere that there is a pssibility that radiactive materials may have been depsited n surfaces, e.g. cntainers, radiactive stre r when a surce has been drpped. Summary f the use f sealed radiactive surces: Lcal rules shuld be written fr yur specific schl site An inventry f all radiatin surces shuld be kept Each time a radiactive surce is accessed it needs t be recrded in the use lg Regular inspectins, wipe tests and cntaminatin checks shuld be cnducted and the results entered int the use lg Page 7 f 10

8 Cnducting an inspectin, wipe test and cntaminatin check Gd light is needed t cnduct a regular, visual inspectin f a radiactive surce which shuld be held at least 20cm away frm yur eyes. All scratches and any signs f deteriratin particularly t the seals need t be recrded. A rutine check and wipe test shuld be carried ut annually. The wipe test is used t check fr the unlikely event f leaks f radiactive material frm a sealed radiactive surce. If there is any damage the surce shuld be withdrawn frm use and dispsed f apprpriately. A cntaminatin check shuld als be cnducted anywhere that there is a pssibility that radiactive materials may have been depsited n surfaces, e.g. cntainers, radiactive stre r when a surce has been drpped. Cnducting an inspectin, wipe test and cntaminatin check: An annual set f mnitring checks needs t be cnducted using the fllwing prcedure: Wear PPE: a dispsable aprn, safety glasses and dispsable glves. Carry ut the wrk n at least tw sheets f newspaper. With all surces at least 2 metres away and using the GM-tube, the backgrund radiatin shuld be measured fr 2 minutes. This backgrund cunt is recrded. Inspect and test ne surce at a time, keeping ther surces in their nrmal cntainers at least 2 metres away. Using lng tngs pick up the sealed surce and carry ut a visual inspectin keeping the surce at least 20cm away frm yur eyes. A mirrr culd be placed n the wrk surface s that the windw side can be viewed facing away frm the eyes. Recrd any small blemishes r scratches fr future reference. Wipe test: Using a clean, dry, paper tissue, gently wipe acrss the windw side f the surce. Mve the surce at least 2 metres away and measure the radiactivity 2mm frm the wipe area n the tissue paper with a GM-Tube fr 2 minutes. The cunt is recrded. Repeat this prcedure with ther surces using new tissue paper and recrd the results Prviding the tissue cunt was less than 1.5 times the backgrund cunt, the surce has passed the wipe test. A recrd f the annual results needs t be kept fr cmparisn and any nticeable changes need investigating fr leaks r expiry. Cntaminatin check: The GM-tube als needs t be passed ver the interir f the lead lined strage bx r metal bx t check fr any cntaminatin. If the cunt is 1.5 times higher than lcal backgrund radiatin then the strage areas need t be carefully and thrughly wiped ut with tissues saked in strng detergent. Shelves and cupbards need t be checked als. The rigin f the cntaminatin needs t be defined. If the surce appears t be damaged r fails its wipe test, nte the actin taken. Keep any such surce inside its nrmal cntainer and place it in a strng plastic bag. Seal and suitably label this bag and keep it in the usual stre. Cnsult the radiatin regulatry authrity as prfessinal dispsal may be required. When wrk is cmplete, place dispsable materials that were used in a strng plastic bag, which is tied fr dispsal with nrmal garbage. Always wash hands thrughly immediately after wrking with any radiactive surce. Page 8 f 10

9 Dispsal f sealed radiactive surces A sealed radiactive surce with an activity belw the exemptin level as specified in Table 3 in the Safety Guide fr the Use f Radiatin in Schls (2012) may be dispsed f withut regard t its radiactive prperties. Hwever it is imprtant t check the current requirements in yur jurisdictin with yur radiatin regulatry authrity. Radinuclide Max activity f sealed radiactive surces in NDRP fr use in schls (kbq) Cbalt Strntium Caesium Plnium Radium Americium Table 3: Sealed radiactive surces fr use in schls and clleges Exempt activity in NDRP (kbq) Exempt radiactive surces d nt need t be treated as radiactive fr dispsal and can therefre g ut with general garbage when they are n lnger needed. There may hwever, be requirements fr its chemical prperties. If yu are dispsing f a surce that has decayed t an activity belw the exemptin level fr regulatry cntrl, yu shuld permanently remve r bscure all markings relating t its previus radiactive status. If yu wish t dispse f a radiactive surce with an activity abve the exempt level, r if yu wish t dispse f any ther type f radiatin surce, such as an X-ray unit r a Crkes tube r if yu are unsure f hw t dispse f yur radiactive surce, yu shuld cntact yur radiatin regulatry authrity fr advice abut dispsal. Summary f dispsal f sealed radiactive surces: A radiactive surce with an activity belw the exemptin level: Shuld have all markings relating t its previus radiactive status permanently remved r bscured and then Can be dispsed f with the general garbage A radiactive surce with an activity abve the exemptin level: Cntact yur radiatin regulatry authrity fr advice abut dispsal Page 9 f 10

10 Radiatin supervisr appintment and respnsibilities Each science department shuld have a named radiatin supervisr nminated by the Principal. The radiatin supervisr wuld prbably be a member f the teaching staff such as the Head f the science department r the Head f Physics. The Principal/educatin department shuld ensure that the Radiatin Supervisr is cmpetent and is fully aware f his r her duties. The radiatin supervisr shuld understand the basic principles f radiatin prtectin and the relevant requirements f the lcal radiatin prtectin legislatin. They shuld be fully aware f the hazards and cntrl measures assciated with each radiatin surce in his r her care. A schl radiatin supervisr has respnsibility fr the safe strage, use and mnitring f radiatin surces. The radiatin supervisr shuld liaise with the Principal/educatin department regarding the develpment and agreement f written lcal rules fr yur specific schl site and ensure that all staff and permitted students wh handle radiactive materials shuld be familiar with, and have easy access t, the lcal rules. The Radiatin Supervisr shuld be satisfied that all persns invlved are infrmed and trained t a level which enables them t carry ut prcedures safely. Summary f Radiatin supervisr appintment and respnsibilities: The radiatin supervisr shuld ensure that: they are fully aware f the hazards and cntrl measures assciated with each radiatin surce in his r her care all such wrk is carried ut in accrdance with the lcal rules regular mnitring is carried ut n radiactive surces and their cntainers all recrds required are accurate and kept up t date they knw what t d in an emergency there are written standard perating prcedures fr wrk with radiactive materials all radiatin surces have been replaced in the stre after use relevant checks have been cnducted crrect dispsal prcedures are fllwed The radiatin supervisr shuld prvide apprpriate instructin and training in: security and strage arrangements recrd keeping (inventry f surces and the use lg) safe handling f each type f radiatin surce crrect use f assciated equipment, particularly that used fr mnitring purpses actin t take if a radiactive surce is drpped r a spill ccurs when t seek help and advice frm the radiatin supervisr Other aspects This dcument summarises the main requirements fr the safe strage, use and dispsal f sealed radiactive surces. There are many ther aspects that are addressed in the Safety Guide fr the Use f Radiatin in Schls (2012) such as radiatin and its prperties, chices f radiatin surces; cleaning up a spill and example Risk Assessments. References ARPANSA Safety Guide fr the Use f Radiatin in Schls (2012) CC BY NC 3.0 AU Page 10 f 10