Document 2R9YdDejXgBGwv9GdvJG7Dqb7

LIA0998 5 * LEAD IN DU SIT ! S3 ASSOCIATION am usxiucroH a v s mm MCW TOW IT, M. T. I i Aagnat 1( 1955 l ead amturw eouaa *>. a To tetin of tha Load InAiatrtea iModiUou Attached la a reprint of tha chapter oa radiation protection fron tha load Indaatrf.ee Aelation*a bock 'Land la Modern Induatry." 8ona rerfeiona and correction! hara boon nia on tha original pohMoa* tion, and tha raprint or* rapraaanta currant praotioa la radiation pro* tnotlon agalnat both warTear rndlatlon and x-rapa. Practical ocwtrac tion tnohnlqaan ara alao lnoladad la tha motion endar x-cap protection. AddlUonal qoaatltlaa ap to tan nx be obtained free of ohrga frcn tha AeeoeUtloa aa long aa our aupplp laata. Larger quantities nap be had at 10 oenta per ocpp. 1 li j Ra d ia t io n Pr o t e c t io n i i fcfX /W LEAD IN MODERN INDUSTRY NtUW V ImI IXaaliW I wariMI-- 4M Aiw m Nr. Trk IT. M. Y. o o N3072.01 L I 0Q9e 7 aumx iHatnxN Radiation Protection ] , Tai harneeaiag of atomic energy ha* brought with It the problem of controlling the powerful ray* emitted during dcnic dirintsgrwt'ca. Bairfeaily the problem of protection from tbme ray* h the tone m from X-njt and radium. Technician* have fee many year* knows the hazard* Urolred m4 they hers worked oat error*! methed* of protection. Bat while today** radiation problem* are riiatlar, they are far more tlgnlScant both became of the wider see of radioectir* material* and the pe> testiaUy greeter Utmeitlee to be worked with. The rarioue typee of rays--alpha, beta, gamma, neutron-- differ chiefly la their ability to penetrate and kmlxe matter. It ie the latter characterUtk which injure* tiring tiaaoe and which oat be guarded aiaiaet The alpha particle la a poaltirely charyod helium aoelece which ie completely (topped by S or 4 inch* of eir or a piece of paper. Beta particiee art high epeed electron* of earying energies. Ia general, they prodoce has ionliatton la matter then alpha particiee bat are more penetraitag. Moet common aobetaacee each ee 1 in. of wood will cec* pletely abeorb beta ray*. Camma rsdlatioa os the other hand baa treat power* of penetration. High energy camma win sot be wholly aheortied by rres a foot of lead while lower energy l*mma may be eafely abeorbed by A or Wee of lead. r*y* prodoce large ecale tooixatioa by a eecondary proceae, that I*, the gasurva rmy flret prodocee a hlgh-epeed alectroa aad thia, ia tarn, prodocee the ionisation. Neutron* emitted by the cyclotron and the atomic pile are uncharged particiee which will alee Ionian certain material indirectly. Neutron* are demised according ta their energy lode ae very feet, feet, alow and thermal, the laet haring the lowed energy level ft o o4 -w LI909989 M LCAO MODZtX IXDUmtT The dangers of txpceura to radiation in daaeifisd lato two separate categories: Internal and external The former U pri orihJy hygiene and medical problem and because It (Soot not Involve shielding u such It will not bo discussed bora. External radiation comoo from a eource outside tbo human body such ao an X-ray tube, cyclotron, radium or radioactive samples. Protoo- tlos against external radiation la a question of shielding tbo body from the raja, keeping a aafa dittaaca away from tbo raja, and limiting tbo timo of exposure to tbo raja In shielding against neotroeo metallic cadmium or a hydrog enous material such aa water or paraffin la general!/ used. How ever, bocauio gamma raja are omitted whoa tbo neutron* art aboorbrd, it is atill noceaaary to provide o protective ohleid of load. Tbo bo o of protective shielding la identical In all raim. regardless of tbo typo of ray, tbo thickness of tbo d*. ponding upon tbo penetrating power of tbo raya. Tbo first consideration In preventing penetration of raya It density. Lead enjo/s the advantage of being tbo densest of say common!/ available material. Where space Is at a premium and utmost radistloa protectioa it paramoont lead la shra/s pro scribed. Another advantage, particularly la shielding Matrons and gamma raya, la that lead doaa not become contaminated. It may be uaed continuously without fear of Itself becoming radioactive and emitting lie own harmful raya. For tbia reason it ie Important that lead specified for ahietdlng purpoees be free of alloying element*, particularly those which may become radio- active upon exposure to high energy radiation. Being a metal, lead baa aa advantags over various aggregate materials such aa concrete la that a uniform density io guana* teed throughout. In addition, because Ha surface la smooth It cannot become contaminated with dirt or other material which, U turn, may become radioactive. Oftentimes where exception- aity high energy level* are beleg ahividvd and where the concen trated load of the quantity of lead required would bo prohibitive, a combination of concrete and lead has been employed. Tbo load may be sandwiched ae a shoot between layers of concrete or may be used on either side of the concrete. Lead cast or extruded lots bricks bat proven especially useful In atomic shielding because the bricks can be easily stored to areas where special temporary , m KAOUTIOM PPOTSCHOM hleldiny U aaodod *ad cu be WOt op to aay thlckama or piaeod la aay poaibea dmired. la atonic raactora or "pOaa" operated by the Atonic Eaergy Cornslaakm, cadmium, had. coocrote aad distance are need la proUct operatic* penoeaei from expoaart to all typm of daa<oreoa radlatioa, chief amtmg tbaac belay nootrooo and p---* raya Nntmi aacapiay from tba oranlom aectioa of reactor* ara abaorbod by a thla radmlaai ehieid. Thl* abaorptiow caaam the cadmiom to emit yamata ray* which aro la tara ftoppad by a had thield. Thue pcraonnrl durlnf the (oadioy aad uctiadioj of atomic fool arc protected from antroaa by the fadmhaw aad from yamaia raya by tba had. la o m typo of roactor a 4 la. ehieid of had-cadmiom ahoy *wrrooada tha reaction area and fit* easily Ineide a coocrota abhM ft thkh which aacama the entire reactor. The Ired radmlcm alloy protect* the coecrete from direct exposure to amtroac aad amove raya. Aa extra 1-ft- ehield of had brick* la located a* top of tha reactor to eompeeaata for tha abaaacc of cowerola Tba thick had thieid at tha aid* aad bottom h coeotrsctad with o T wwuww%wgpi^w^iit wyiMwwp.nju im m i ui>. i. m.i m LI AC9991 1M 1X10 tx MOOKJtN onom Internal eofper table* for circulating ooolln* witer to warn hca! *tn*r*!d ia tbo ehield Itself and th exterior of tbo reactor tbaUr. A ccbaa made of graphite bricks extend* Into tbo Wit of the reactor to proride path for thermal aad Mow cmtree*. The end of the oduma protradlnj through the ooter concrete ahield U covered with a cadmium curtain and a J-ft. Ic'd aad lroa ehlcM In which aa 4-la. aquara opening ia provided for erenm The fret uranium-graphite reactor, breeder of the original Atom Bomb, locked liie a windowkse two-etory equate ouotrrte building. SO ft. vida, S2 ft long and II ft. high. Oa the aides ef thie earl* reactor concrete ekie wee depended upon for proteo* tlca. The top ef the pile was pared with 9 la. of lead, totalHag about 14S tone. Oa top of the lead wae aa additional layer ef 4 ft. of solid wood. Resting on tbla ehWd waa enwO experi mental laboratory ia which operating pereonaal worked. eerara in the troet that the* ware beta* protected from the irmee> done enerc* beta* generated beeeeth then by the 4-ft. layer ef wood aad 44a. layer of lend. The table given below prepared by the National Buena ef Standard# me* be need to determine the required thickmaeoo for shitiding from gamma re* aoartea la the lahcralory. To see the table select the column for the energy reqalred (nee next higher if exact value le not gives). The entry given thickness la end meter* of lend for dilfenst eoaree etrvngthe at 1 meter for f hryda* te give M mHUroestgana. Thea add elgehrelreHy An correction term# for other working ranger or timer te oMaia the thield thickness required. Example: Shield ia reqalred for the manipulation of 404 miiUcuriea of radioactive material emitting 1J million electron volts (Her) gamma rays st a minimum working distance ef 40 cm* aad for 4 hr/day. Shield thickness-140+1.77-!.-Mi cm. ef lead () (b) (*) La wkieh a-basis entry. b-correctkw for danger raagaoH o l e-correction for 4 kr/dny. | . i I o W`wu' LI AC9992 L*ft- 1* ft n liftft^tl UWftlarf ftftftrtftl Wl Wv m >Wrt tt tadi unai4 Ka 4. w ^< kncfe "In*"' Um Ml #yH Ni|V> U- ha* ka +tpm*i o P4MP L I AC9993 ijwiu ui ii jiuinnuwimapiwmwiM m.uri'imiWJU^J 3 LI AC-9994 KE^UIttD LtAO i81KLt>U(0 THICK*E31 FOI QAMMA KAY* > ( A*J ttam. ..... M m*....... Mm........ 100 m........ KO ............ MO M........ U.......... .................... u................... t!o*................... 00*.................... 100*.................... 1 ft! .KM KM 4MT +0W +U1 +u 4141 + 14* 4 KOI 4Ht 4LU 4*M 404 ft -t*r 4*41 4141 4LM 4in 4147 444* 44.01 4*41 4*4* 4 7J* 4 KM 4K1* t - Kll 4- K7I 4- 14* + ITT 4 Ml 4 171 4 Ml 4 lit 4 TM 4 Ml 4 041 41044 4U4* 14 4 047 4 147 4 Kll 4 <44 4 144 4 7.11 4 Ml 4 Ml 41141 41KM 41M* 41*0* 41141 M 4 KTl 4 Kll 4 *4* 4 KM 4 KTT 4 MO + KM 4UJ7 41141 4U4* 4IKM 41741 41141 II + U* 4 KM + *47 + *o* 4 741 4 *07 4104* 4110 41*47 41141 41741 41*47 4*17* t*mm h 10 cm. ...... Mm ...... .......... U.......... l .............. . -4JI 10 m........... nm 4144 4KT1 KM --KT1 -144 -to* fto 411* 414* tM -14* -114 -in nm 4 1M 4 KTl KM - KTl - 44* - 114 nm 4 141 4 KM KM - KM _ KM - TA4 nm 4 1*4 4 KTT KM - KTt - K44 - KM nm 4 10* + KM KM - 1M - Mi - KM M + Ml 4 1*1 4 1M 4 Ml 4 74* 4 *41 4U-41 41KM 41*41 41M1 41741 41*41 + 1141 nm 4 14* 4 Ml 1M - Ml - 741 -1*41 .M M/m. 1 ......................... t ......................... ......................... ......................... M ......................... nm nm -104 --KTl -KM 4KM nm -KM --1-04 -KM KM 4VJM nm - KM - 171 - KIT KM + 147 fto - lit - KM - 141 IM 4 UK nm - Ill - in - 141 KM - KM - 141 - to* - 147 KM 4 1*4 >w town/ I* <Mini * mmmm m wmmm* to* t *to* 1* Vto< * -- i * to MM rf ft t * Moltf**t*mm M Mil IM HIM M IH| llrf M tto f*RM (<>!l tTWV* Im m--At MiMte*a*>Ktui*M*i**I***t nm - lit - Ml - 141 1M 4 KM u 4 LW 4 Ml 4 KM f KTl + Ml 41*41 41141 4 IMS 41**1 4U4I 41*4* 4*04* 4*1-71 nm 4 *41 Ml M - KOI - TM --1141 nm - 441 - 1M - 141 KM + UK If mmmm LIA0999 UAO iQcnrALKXT* or TAttooa tumuu S S I5sR ft8B&* Sb s b c s L I 409996 mm 'WW * iu d u t io m rtorecnoM im Some common pplle*tiona of I**d to th* deroktpmoot of aiomi* tatty and In tbo handling of radioeetie* cut*rial* lacfod*) lead brick* (Interlocking or ordinary racier.r-il*r), Uad plat** aad cartinga, "hot" laboratory tab!* and dak top*. torag% carrying and ahipping container*, lead rubber glove* aad apron*, load glau apron*, lead glut window*. Ctigv counter tub* ahieid*, load ahot. lead *b<*t sheathing, lead beaded sail*, load pi/wood, lead lined cinder block*, laad tafea, aad ao otf. 1 , X-RAT PROTECTION X-ra/s ar* wide!/ tmd both b/ th* medical pref***Soa aad by induftry. Sine* the** ray* can cause phy-skal damage to peracne cipoeed to them ft i* necessary to encloee X-r*y generating b b IU la chamben mad* of or lined with material which U reaistant to X-ray penetration. Sine* th* Impermeability of tb* ah!tiding material la a function of ita density, lead, which ia th* denaoet commonly available material, will gif* th* create* pro tection per salt of thlckne**. Lead ia the leaat bulky aad onally the Ugbteet and moat economical material for meh shielding Although certain type* of X-ray machine* Intended for pro duction line operation are *elf contained ia lead lined cabinet* with automatic controle to abut off th* eocra* at power before th* door* can be opened, genera) X-ray department usually re quire* th* provision at a lead lined room. Such a room mn*t bn carefully planned and conitrucled with th* lead Being of auf&cient thicknom to keep th* eapoeure of peroon* la Ita vicinity below aafe tolerance limit*. The principal factor ia determining tb* proper thickneea of lead la, of course, the iatenaity of th* X-raya to be generated but conalderatio* muet aim b* given t* th* cumulative time of operation during th* working day, th* divtance of th* operator and other pereone outside th* room from th* X-ray tub* and th* generation of ecattered or secondary radiation given off by object* la th* path of th* naefu) beam. Tb* intensity of th* ray* 1* a function of th* voltage Lmpreeeed on th* tub* and therefore it ia customary t* nm voltage aa a primary guide in selecting th* proper thickneae of had required for X-ray protection. An accompanying chart give* th* thicks*** of aheet lead protection recommended for lntntton of rarloo* voltage* aad correlate* them recommendation* with commercial Oo LIA09997 1M ` UUD IX MODKXX IXDC*TXT TVhra tl 1m4 Wt X n^alrW to nM X rmjr mr> ru <> h M tm to W* Bimnaalftoto H < to4w*l4 -- <WI--i Q f r ad iat io n pr o t s c t t o n 1M thlelrao** of iWt lead. Having selected the proper thickness of sheet lead, the principal feature to watch la obtaining effective thick} Ing It to mo that oo otto minute space exposed to the rays li loft unshielded. Thus d o screw or nail holes, tritk or tcUkoat *cmt4 or nails in lin, or cracks around door* ut left without being completely abut off or ahlaldsd by load. LEAD 8H1ELDIN0 CONSTRUCTION There art a number of methods of applying lead for X-ray protection. Serrral special devices Incorporating lead art avail* able for wall construction. Theta Include sheet feed bonded at the factory to plywood, wall or other board materials oa one or bcth aides with special lead covered strip* for covering the Joint* and special lead beaded nails for securing the materia] la place. Aaothsr device le a concrete or gyp#urn Mock with aa unper forated sheet of lead anchored at lta center. The two halve* at this block oo tech side of the lead are about 1 in. off center so that their edges are offset by that amount. The sheet lead, how ever, extends to the outer edge all around. Thus when a wall Is built ap of these blocks, the lend la one block overlapa that la all adjoining block* by 1 in. and providea a continuous lead lin ing. Other special device* include lead-Uned doors and leadcovered windows filled with glass containing a high percentage at lead. If eoch special method* are not used, there are a number at way* of applying sheet lead linings, all of which art satisfactory and the choke of which may depend upon the type of construe tk* and other Installation condition*. Some of these method* are dmerited km. In one method sheet lead Is placed against the waB surface er stud* with the long dimensions of the sheets running vertically. Sheets should not exceed 3d in. la width for case of handling and should be of such width that Joints will occur over vertical sup port*. Such Joints should have 2-la. overlaps. At the top, sheets should turn out at least 2 la. onto a continuous horUontal sup port. Over the lead at Joints and at about Id in. Intervals, 2x4 la. wood strip* or steel angle* or channels are placed running from the floor to ceiling. These are secured top and bottom aad mrnvm LIA099Q9 IM 1XAO Of MODBSX WPCfTBT at latanaadiato potato, th* tpactof of which kywk e th* waiffct of th* load bat la m c o m thoald b non th*a 4 fV, by boltln#throujhth*l**dtotbw*H. Oa* or two horttontol bracta btlwocs *och pair of *tud* may b* a**d to (if* additional (ex port to thick Union. Laad patch** u* th& w*id*d or *oid*rd to th* k*d os tach aid* (nttr til boiU. Then patch** thoaid * toad Mf*r*l inch** la *och direction beroed th* boh hoi* to that ; rayi ctrikins at ta *n$l* cannot portrait th* bolt boUa. Utal ( : Uth can than b* fattened to th* support* aad th* wall ftnith*d j ta th* two*) way. Patch** should b* of th* mb * thicks*** of j t**d ** th* Unlnf to tilalnato aajr po**ibCJty of k*i*f*> j A zsftbod Mhabl* for 104*00(7 walk k to bOd t a 4 la. wood tod* lata aad floth with th* wall at 14 la. totorrak. Sh**t laad with th* toes dimosaic* naalas vertically may tha b* acr*w*d LI AlOCOC mm mmmsmm m ----------- juDunox noracnox uv to these studs. A perforated (tool strip afalnst the toad under the screw heed* helps to distrfbata tbs load. Strip* at iood may tha bo pUaod over tbo servw hoed* or Moot strip tad votdod or sold*red to tho ohoota on oscb aids. Screw* should bo about I to. opart A silfht variation of tMo method to to screw tho odft of ontp eoo shoot to each stud. etiowtnf tho odjo of tho ad> Jotclap shoot to ovsrlap tho serrw beads and stool strip sad bo woidod or soidsrod to tho first sheet thos eoerlnf the screw boles. Still soother method Is to o m borisoetal wood atosparo boflt Into sad fiush with tho w&Q it 2 ft. Interval*. Tbs shoot lead Is thsa applied u in tho previous methods, bet with tho loaf dlmwisloas runnlsf borUoctally, Os screw beads beifif eorerod so before by overlapping. Another method sueeoesfolly nasd Is to employ boards screwed borlsoata!]/ to refolar stud*. Tbs lowest boards are applied first to s height of shoot 18 la. sad are then eooered with a ehest of teod which to turned beck ooer tho upper odfe of the top boerd and then turned epward aboet 1 la. afaiost tbo stada, wbero It to screwed. Another tier of boards 18 la. wide to than epplied In tbo tame way, fitted down orer tho setback of tho first sheet of toad, and covered with lead la the same manner. The joints between the lead sheets are then soldered or welded. Sheets la all caees should be best around corners end at Met* section* to thet they can be welded or soldered to the shoots on tbo adjoialaf waQ to make tbo Hals# continooua. Wall sheets shoold bo turned out several Inches on tbs floor to laser* ample lap between wall ahleldinf and floor shield!nf. Tbs toad Unlnf should also bo carried around tbo rabbet of door jambs so that It win overlap tbo Uaiaf of tbo door Itself when in tho ctoood position. Wbero pipe* or wins penetrate tbo toed Uniat they should be fitted with fianfsd toad elbows welded or soldered to tbs toad Unlnf and so deslfaed as to prevent paseafo of ray* throufh tbo openlnf. Pips* or wire* passlnf throufh tbo waU may bo offset so that tbo openlnf throufh tbo toad Unlnf can bo becked with a Ian* lead patch o# the outside. Electric switch basso shoold also bo backsd with toad patches mack larfer than the oponiaf a* that rays eaaeot pass throufh tvs* at an aafla. w .mil.mi nee LEAD tx MODESM tWDtJITET Protection on trillno may be accomplished moat easily by laying bad, with overlapped Joint*, on IS* Door abort of on l drop celling. la auch caw*, tht lining should bo extended well beyood tbo load walla balow It Tbla projection of tha floor Uniat ahould ba enough to prevent paaaaft of tha ray* through tha tap of tha floor construction batwaaa tha load walla aad tha load oa tha floor abort, aa tha raja trartl la a etraifht Una at aa angle to tha wall and retting. Load takaa paint wdl without apodal preparation, ae load flniaga may simply ba paiatad to prtaant a pbaalag appearance. If such treatment la intended, a baaaboard and a chair rail ahould ba providad to prevent danaga to tha land by baing (track by faat or furniture. If a plaster ftalah la desired, metal lath may ba applied to tbo aupporta previously daacrlbad and tha waB ptaatared la tha uaual manoar. Wall board may alio bo applied to thaaa aupportai Wood floor* to ba laid over load linings cither in (ha X-raj room or la roocai ovtrbaad ahould ba laid on floating alecpa re. care baing taken that no nafla panatrata tha lead. Co* meat floors may ba laid over lead Uninga but if tha bad la bft espoaed without Immediately pouring tha concrete, It ahould bo protected ogeinat mechanical damage by a layer of heavy buildlag paper or lS-tb. felt In either ease it la adviaabb to protect tha bad from (ha actioa of "green* concrete by coating M with a thin layer ef aphaltum.