Dissolving of Twenty Day Metal at Hanford - Development Division Health Instrument Divisions

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Operated for. the Atomic Energy C o ~ ssicq General Electric Company

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two ton batch loaded intoa clean dissolver on December 2, 1.949. Calculated amounts of activity evolved !#ere 4OOO curies o f 1-131 and 7900 curies o r Xe-133; masured values were higher tkan this by a factor of 2to 3. Preliminary calcul a t i o n s of the hazard were u.do by the method of 0. G. Sutton and attempts made t o check these values by rea?.ings on fixed and mobile instruments. The meteorological cocditlons-during the actual hours of dissolving were unsta61e rrith t.b winti veering from a southerly direction a t the start t o a northduring the run indica*Yed as b ll orr surface inversion with an unstable condition One ton of ir redir tc ? uranium with fifteen days cooling'was dissolved from a It i s postulated that much of the dilution occurred ahve the inversion., Readings a9 high as 2 x 10.4 uc/l.of 1-131 and 2000 t o 3ocO c/m on portable Geiger counters were obt2incd nith in a radius of 4to5 miles from the steck, Significant readings rppearcd inthe Aichlnnd - Pasco - Eentori City area abut ~. of Dec nber 3. filters. & Spokane on Docemkz 3 and Decrmbcr 5 , 1949. Aircraft measureents d o i n the direction of Spokaneaon acember 3, 1949, indicated peak activities fn the rroraing a t Ritzville and betzeen Richland and Connell, It is postulated that the peak closest t o t h e project ras due t 9 1-131 while the one at Ritz ville 183 due t o Xe-133. La tim ted maximum concentrations Fcre on the order cf Considerable deposition occurred particularly close tothe stacks. vegetation readings, above the pe-cmanent tolerance value of 9 m u c k occurred over a region extending frcm Tho Dalles, Oregon, t o Spokane, end from Y a w tothe Blue Uountains. vegetation decayed t o bockground with an eight Gay half-We, The rate of deposition in water was estimated at2x 104 Exposures of clean pokted plants in the area gave results comparable t o those found in other plants, Anizals collected from the region indicated that from tolerance t o 80 times tolerance daily.

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The request for this operatio smtatives of the Gene- a ect ric compsay and &he Atomic Dlorgy Cod sion on the bufldings and poesfble ez qo s tae of ponomrel, CrifxrLi decided upon for neather

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feet high 3attlesnake &untain t o the amtk of the area. (5). Conditions where@ the bdk of the stack effluent would stay aloft.A dilu-:ion factor of l5OO:l was decided upon aa the lowest permissible fector. A review of date from the past several years a t the HI7 Lleteorology Station showed t h a t during night hours a t this season of the year the "aloft" condition _orevailed 76% of the tine, and that th3 dq coverage amraged 6.7 on a scale o f 10. t o 10-ll qh a t the @G foot level. de rate &version u sud ly overlies the area a t night, forming near smaet 2nd ter - minating about one-half hour after scnrise. The prevailing d he c tion was northwest. A Norwally, precipitation is infrequent - .and the' probabilltp of its occurence during any particular 24 hour period i s d w ~ s The abova statistics indicate tht the chance of flndiag favorable neteorological conditions for the dissolution on q part im lar date mi&% be good. However, the month of November, 1949, was plagued nitin inclement weather which included two periods of recurrent storms with attendant whd and rain, interspersed by alO - day stagnant period during which c e u g were continuatf-1 low and fog was present on an average of nearly 19 hours each day. This inclement m a t h e r necessitated postponement of the run for 038 mek. 3n the mdrning of December 1, the United States Veather Bureau in a s p e c i a l ' forecast to this plant, predict* thst.the end of the a r r e n t series of frequent atoms waa in sight, and that conditions favbrable for the operatior: could be expected bp S a t e nigh$, December 3; The dissolver was t h 4 loaded sdi that operations could'begia Friday night, December 2, if conditions were favorable. The US" Division, in charge of the actual dissolving, elect a i to use the spare dissolver in the nTR plant (200 Ye3t kea) 90 that the "heelm resulting L%R tho dissolution of aalp a portion of the = t a l cbarged, could be stored B the d i s -

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wei% loaded into a clean dissolver on December 1, 194?, and the jackets dissolved on $he 12-8 shift on Deccmber 2, 1949. Tho actual length of the dissolving time CG’*Jd not be pmi!ictQi accurrtaly since nod opsrating pm cod ce calls for three~ f m 3 of metal per cherrga on tsp of (i one ton heel. h estinate of 12-16 hours f o r The am3unta of 1.131 and Xc-133 in the metal after 16 days cooling =re os”;imted a t 6150 end 6370 d - e s per ton mspectively. Assuming thct 5s of the ioai;le(2) remains in the dissolver a d that there is a 3G$ increaao over the avens in thc armunts of fission products in *.e outer portion of th6 slug, the dissolution of one ton nould l lber rte 4000 curies of 1-131 and 7900‘d e s of Xc-133, Slnc3 the off-gns scrubhem mre not operated, aU of this activity would be disThe rate of dh char ~mas os th ted from thrco evolution curvos mooswed In 1947 bp t h o Bo I, Divisions,. These, curpes indicated tbt dth e i & t hour dissolving poriod th8 Xc:133’rea&es a mndmua in 1 4 2 hours and t h e 1-131 reaches a indicated a xanon peak a t about throe hours and DD. iodin0 peak at a b u t seven hours after the start. The mnxinxum rate oE omission XBS estimated a t 0.Q curies/sec f o r Xc-133 and 0.14 ctt-ies/sec f o r 1-131. These values would =\art to about 28 u c / I of Xe-133 and 10uc/l of 1-131 in tho stack on the basis of an a i r f l o w of 25,000 cfm up the stack. . The st& wns p b e d for 2000 on Docember 2 aa a comprodso betwen the A&

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id*%t h e octivitp pattern found, . Xeoorts of forecasting End oh emt ion stations mer the No--thffes': we= u3-d -to-g etc clear pic- of the weather for weeks &fore the test. ~naddition, a mobile TLaninsonde station and two pi bsl M its were mvod into the dc UW of tbe

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Coefficient8 f o r Suttonfs Esmtions on Diffusion in tho laver Atmomhere coordinates I, y, z on e system Thore the origin i s at the. source and t h e x dinen - a pure number lying htrreen 0 and 1. The precise value is re poked cs a meah - the hoight of .the stack in meters. Values of the'cogfficients Cy, Cz end EJ we= abstraded from pcpers o f Subtan's 83 he used th cm for to sts in Porton, &gland. This i s one of the weak poMo In such a ccrlculation since tho conditions a t Hanford rre undoubtedly different with rogard t 7 gustiness, etc. would lx.vnluablo in foreseeing hazards a d 3n interpretfng redts. Hwover, it was folt t5at est bati ops by this mothod

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fn Figure j appear the calculated concentrations from a conthuous point source 200'. above t h e ground a t distances up t o 200 miles. These coccentrations are the rnexhm expecteti Long the d s of the cloud if it is assumed that ui for nse te on - logid conditions and flat terrain ere encountered throughout the entire path of the cloud. Two values are @yen f o r each distence: (1) the coefficient of t h e t h e Kind speed in meters/sec, and )r: is concentration In uc/l; and ( 2 ) the n c t u d concentration f o r an emission r a t e of 0.05 curiea/sec (close to the average expected f o r 1-131) and a wind speed of ll mph. Figuse 4 present's an es th te of the Tidth o f the cloud a t various distances -- it is assumed that the wind is'ateady in-one dir oct bn.In this case the cloud width is defined as the distance betwem the two points on the extremities that The xwdnmm activity expe-cted at the ground is presented i n Figure 5 &der the same conditione as f o r the air concentrations. steady moderate inversion condition rrith a wind s p e d of 3.l mph i s given in Figure 6 . The ground pattern expected fora Fixed instnrments were located a t strategic spots wkere power was available on the res e nation, The location of monitcring instruments duhg the run is ginn fa Pipre 7. All of the wu nth g rate metors and most of the ak. scnabbora were plrt out specislly for t h e operatfon end later removed, (I). TWOmen in fom wheel drive equipment wore to at tm pt to locate the point ~ k .concentration and make traverses across the cloud takfng wsdings out the followbg jobs were planned: on portable CM counters and muall scrutrbcre designed to puU one cubic foot of air (2). men were to operate a radio transmitting c11 WuIltor, m t the

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balloon t:, severel hundred feet SO thct tnverses ofthe cloud a t the axis could' (3). One man was to travel from the inter so dion of mutes 4S and 2s t o several des above Hdord reading detschable chmbers every mile and tddng sail scrubber rad portable GX readings, (4). %o Ipen were to travel fron: Pa koto ConneU witha recoreing CId counter, rind o 1 4 2 CFX d r scrubbar operated from a mobile generator. (5). C&e man was ta check all in stm kts durFnE the run and tc take s d scrubber sqles on the reservation. trol radio steaon, T ~ U Sit was possi ~ ot o mports from the fi ou. cars by radio, from dous ' smy groups by telephone, and moteorologicd. data from the apccial units set up by the Bir Forces bj tolephone. This b o aUmeC the use of the plotting mom facilities in conditions approdinating those of an actd emergency and was very valuable in gaining infomation on ts-es. The plotting mon was med bp Health mtnzmnt Personnel irom 1900 on 12/2 t o 1000 on l2/3 and by tm U r Forces rqreseatative from 0100 on l2/3 to lo00 an 4

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In jpnczd., a brisf discussion of the equipment and pnccdL-s used forQ parti cul sr reeding o r series of sadia gs is include2 in the section ?-seating the date. This s e c t i o n of the report is fntended'b dsscribe those items which der replace the vuuun-tube slectroi~etarcircnlt and Brown recorder.

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ischemntic diagram of thc monitron agp ess in Figure 8 and c photo p ph of I complzts W n it D ring set up iu Five 9. lect ing tube shorn here i s considerzbly shortcr than that used in tlle drcr - a . (The set- shown is for ground monitoring at 2 l o w velocity a i r flow.) Bowever, it nill bc noted the t the col- (7)This unit was described in reference 1and mre flrlly by the desi per s a iowcoer, because the "Cn chaMcl vent out just pd or to the nm, the setms used os a straigbt counting rat0 meter with no coincidenco canccllnfion. The tube bank wns differont fma thase arigFnaUy usod. Instead of t h o netid counters, gless countcr tubcs cere inserted into 1" bress sleeves the -*stnmcnt division t o give approxhikoly the tamc density as thom c td. counter. 3. AM: Filter Box A standard d)rl= filter bx is mounted on thc aircraft in the position shorn in Figure 10. 1% =omdates tm 8" x 18" filters and pc&sos a b u t 450 cubic foef of air per nlnuts through oach fil to rat 150 -os per hour indicated girspoed. 4. Externd Counter Tube For the first tinc on t h o project, nn external bata counter vas used. The assenbly consisted of a Tracerlab stahl oss s to cl counter tube mountcd thq the filter box on tno aluninum brackets, A defloctor cap shielded the tube fmn tho direct blast of the sUp-strcrrm and also coverod the CO-ndnlconnection. The coo- cable passed throu& the front munt and terminated a t a pro-anpllfior just insldo the cabin of tho &craft. N sos from this cat b de - fol lmr stc.go were fed into as der for munting. A sketch snd phohgnphs o f t h e asscnb@ follow in Figures U, 12, and 13. The Health %struneats Divlsion installed inthe aircraft a systen de-

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sip cd to l*scnab" b - e iodisle from the air pessing through it. tkrough the liquid from the bottom and sF1attered the caustic solution on tho filter. 3o'h the solution and the filters were enalyzed for iodine contmt. 9ifficulty mt encounterad when t h e system was In operatian. It was found t h a t by t&&g the air for the scrubber from t h e exhaust end of t h e conductivity tube, the head of solution roduced the airflow thro ub the conductivity tub0 t o suc!~ a low TLlue that much of the co6ductivity sensitivity vas lost, and the scrubber had to b disconnected during the flight in orde;. thet tha readings taken fmm the contiuctiA standard General Electric Leak Detcctor vas pu+ aboard and qd pd with a recorder. The probe wes t3ped toa rpindoi dth the tip. extending thou @ the Window into the supstream. Portable Geiger Counters used f x ficlld ma-purcmcnts were mstly t h e Tictomen Idodel #363A as ll s ted on page S G - 3 9 of the AEC Radiation k str ment Catalog #l. A few reailby wore nade listed on Sa-188 of the s ~ w 3 The counter used for the low voltagc thin md3. counter with,thc El-Tronics Portablo Counter b 2 e l #id3 as balloon asccnsions uas a modified mark II, M e 1 21 Counter Taboratorioe, Bc. This instrument uaes a and is horn 10- as t h e "atomic blink&. The case and all surplus parts were romved sr:d the circuit re heed on an alunimm rod framework with the tubs protruding unricraeafh so that all ps sib lo might would'be rcmvod. The wgb voltago was sq …