Safety_Series_025_1968 - gnssn - International Atomic Energy ...

This publication is no longer validPlease see http://www.ns-iaea.org/standards/One o f the m ost striking exam ples in this connection is the useo f unsealed so u rce s fo r painting lum inous d ials, etc.2. 3. 2. 2. Use o f radiation gen era torsR a d ia tion -g en eratin g apparatus (X -r a y tubes and p a r tic le a c ­ce le ra to rs such as Van de G raaff m ach in es, betatrons and c o s m o -tron s) may involve w ork ers in exposure to: the direct particle beam(instances of occupational cataracts resulting from a cy clotron p a r­ticle beam are w ell known); o r the secon d a ry radiation em itted bythe ta rg ets, u su ally X -r a y s o r neutron b ea m s. The dan gers varya ccord in g to the m ode of operation o f the apparatus (the neutron e -m ission o c c u r s in the Van de G raaff a c ce le ra to r at a v ery highvoltage), and a lso a ccord in g to the target m aterial.Som e o f this apparatus is o cca sio n a lly u sed to p rod u ce ra d io ­nuclides, so som e contamination hazards a re a lso encountered. Howev er, the main hazard by far is external irradiation.2. 3. 3. Transport o f radioactive m aterialsT ra n sp o rte d m a te ria l can be d iv id ed into: ra d io a ctiv e o r e s ,typified by th eir v e ry g rea t w eight and th e ir low s p e c ific a ctiv ity ;irradiated fu els, typified by th eir sm all bulk and v e ry high sp e cificactivity; and activation and fissio n p rod u cts used as s o u rce s , alsotypified by th eir sm all bulk and high sp e cific activity.T h e re a re tw o kinds o f h azard a ris in g fr o m the tra n sp ort o fth ese m a te ria ls by roa d , r a il, ship o r a ir , e tc . : the r is k o f e x ­tern al irradiation when the radioa ctive m aterials are gam m a em itters o r en erg etic beta em itters; and the risk o f ra d ioactiv e con taminationonly in ca se of damage to the container or package, due forin stan ce to a tr a ffic a ccid en t. The s e r io u s n e s s o f the a ccid e n ta lh aza rd s depends on the nature and the am ount o f the m a te ria lstra n sp orted .2.4. CONCLUSIONSIn sum m ing up the re su lts o f occu p a tion a l e x p o su re h a za rd s,tw o types o f circu m s ta n c e s a re to be distin guish ed.The fir s t type co rre s p o n d s to n orm a l w ork ing co n d itio n s. Itentails the risk o f external irradiation o r radioactive contam ination61