Usefulness of Brookhaven Reactor in Isotope Production Program

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USEFULNESS OF BROOKHAVEN REclCTOR IN Prepared by the Division of Technical Advisers New York Operations Office

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TABLE OF CONTEXTS I o ISOTOPES PRODUCIBLE IN THE BROOKHAVEN REACTOR, e o 4 D o Brookhaven Production of Cobalt 6 0 0 0 0 0 e 0 0 0 0 0 0 08 E, BNL Production of 8 Day Iodine 131e e 8 F. Isotopes of Higher Specific Activity than the Activity Specified bi the Isotopes

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The Brookhaven nuclear reactor is expected t o reach full power (about 30 megawatts) by Spring of this year; on January 24, the power level was 15 Brookhaven has offered its irradiation facilities as an adjunct t o those presently used by t h e Cormnission*s Isotope Division. Such services c m be provided without seriously handicapping the research activities at Since the power level of the reactor will be about 10 times that of the Oak Ridge reactor, it i s apparent that the use of a small part of its capacity can provide a substantial quantity of isotopes. advantage in the fact that the flux density available a t Brookhaven i s nearly five times that of the Oak Ridge reactor, thus developing substantially higher specific activities of short-lived isotopes, The small, continental., northeast area makes up a large fraction (45%) of the isotopes consumer market, and Brookhaven possesses marked geographic advantages i n supplying this market. convenient shipment t o most other parts of the country as well. It has the added advantage of fairly O f the 106 radioisotopes that are produced a t Oak Ridge, 59 require irradiation only, without chemical separation o f any sort. produce and distribute any of these isotopes that the Isotopes Division authorizes. Of this number, 1 9 isotopes have half-lives shorter than

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3-days; i n these cases Brookhaven has not only geographic advantage i n shipping t o most parts of the country, but 8' decided advantage i n permitting higher initial specific activity. The advantage i n having Brookhaven supply short-lived isotopes is illust rated by present arrangements for the production and distribution of ?.?a 24 and K 4 2 , which together constituted 8% of a l l isotope shipments of last year. Brookhaven can supply Na 24 at less than one-sixth the Oak Ridge cost per unit activity delivered a t N-ew York Hospitals; K 42 can be supplied a t one-tenth the Oak Ridge costo , * Phosphorous 32 (half - life 14.3 days) constitutes 28% of isotope shipments and can be produced conveniently by irradiation at Brookhaven and chemical Consideration i s now being given to this Iodine 131 constitutes 35% of isotope shipments. The separated form is obtained a t present by chemical separation from fission products. However, I 132 (2,4 hour half - life) produced i n the iodine generator now being developed a t Brookhaven may partially substitute for I 131 because ofits greater usefulness i n medical therapy. Brookhaven i s working on as at is - factory method o f supplying I 131 from irradiated tellurium t o New York 'customers i f the need should arise. The Brookhaven reactor offers 300 sample containers, conveniently arranged with endless conveyer t o external charging and discharging stations and the Brookhaven reactor and associated facilities offer flexibility and unusual research facilities to accommodate special irradiation SerPice,,

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The nuclear reactor a t Brookhaven will have a power level about 10 times that of the Oak Ridge reactor and can be used t o supplement neutron irradiation presently available t o the Isotopes Division. production cy a city is roughly a function of the available neutrons, Brookhaven would have t o .use only a small part of its total flux t o add substantially to the curie capacity- available t o the Isotope Division o r to relieve Oak Ridge of part of its present load thereby making available reactor flux for other uses a t Oak Ridge., ' Although, i n general, Brookhaven can make any reactor-produced isotope that Oak Ridge can make, there are specific isotopes mhich would be more advktageously produced a t Brookhaven. These are discussed below, A. Isotopes Not; Requiring Separation Table I lists isotopes xhich do not require chemical separation. Since Brookhaven's usable neutron flux density i s about 5 times the Oak Ridge usable flux and since Brookhaven has adequate target facilities, Brookhaven can supply all of these itemse Also, Brookhaven can supply higher specific activities than those listed in the catalog when required.

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Unsepareted Isotopes listed in Catalog Classif.ied i n Ranges of Half-Lives Ba 131 Ir 192 Ag 110 Users of fast-decaying isotopes want a s much of the original activity as possible to arrive at their laboratory, making it desirable to cut the transportation time between supplier and customer toa minimum. Sodium 24 (14,8 hr) and Potassium 42 (12.4 hr) will be supplied t o local New York Hospitals by Brookhaven beginning February 1. Ekamples given below compare Brookhaven a n d Oak Ridge as sources of supply f o r Na 24, K 42, and Au 198 (2,7 day) t o laboratories i n New York City. 6% of a l l isotope shipments were N a 24, and 2% were IC 42, and t h a t 45% of all shipments were t o the northeastern skates, it is clear that production? of these and other short-lived isotopes a t Brookhaven will offer very real Considering that last year, At t h e College (of Physicians and Surgeons, New York City, patients are treated with Na 24 atthe beginning of each week. Comparison o f costs per unit activity received a t the hospital give Brookhaven an advantage factor of 6,5 over the cost of N a received from Oak Ridge,

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Oak Ridge Brookhaven Activity when shipped 1 5 mc 15 mc Transportation time 36 hours 3 hours Activity at hospital 3 mc 13 mc portation, service charge) Cost per milli curie re- $ 25 Advantage factor in 1 ceived at hospital ,-The above calculations were made on the basis of the15 mc unit listed - i n the Isotopes Catalog. per milli curie would be less. Actually this hospital uses 50 mc units and the cost Other comparisons f o r K 42 and Au 198 follow: 12,4 hour IC 42 shipped t o New Pork City Oak Ridge B r ookhaven Activity at shipper 125 mc 125 mc Transpor 'tati on Time 36 hours 3 hours Approximate cost of unit

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2,7 day Au 198 shipped t o New York City Activity at Shipper Oak Ridge Brookhaven Approximate cost of unit $ 75 Cost per unit activity 82e15 C e Isotopes Requiring Separation 1, Brookhaven Production of 14.3 day Phosphorous 32 f o r Separation, P 32 i s supplied fin both unseparated and separated forms. P 32 shipments last year constituted about 28% of all isotope shipments, irradiation of sulfur to produce P 32 a t Brookhaven could substantially decrease the work load on the Oak Ridge reactor. has already indicated interest in having cans of S irradiated at Brookhaven; The Isotopes Division the irradiated csn s would be shipped toOak Ridge for chemical separation i n order t o prepare the separated form, Acm of S taken out o f the Oak Ridge reactor after a unit time of irradiation will have a certa:in activity ; a similar can taken out of the Brookhaven pile after the same irradiation time, will have approximately 5 times the activity of the cm irradiated at Oak Ridge. days transportation time to Oak Ridge for the 14,3 day P 32, about 85% of Then, assuming a maximum of 4 the initial activity would arrive a t Oak Ridge, This means that about 4,3

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times the activity-would be available for separation a t Oak Ridge, for equal irradiation times inthe two reactorss Another way t o look a t the sik ation would be t o recognize that Brookhaven could supply the same activity which Oak Ridge i s producing i n about 1/4 the time of irradiation required a t Oak Ridge. Ridge i s using a 30 day irradiation time. equal activity in one weeko A t the present time, Oak Brookhaven could supply an D. Brookhaven Production of Cobalt 60 With Co 60 (5,3 years) the activity lost in transportation between Brookhaven and Oak Ridge would be negligible. 1% of total shipments last year. Co 60 shipments constituted about The demand f o r more Co 60 and higher specific activity per shipment,will probably increase a s Co 60 i s made t o substitute for radium; -several hospitals either have switched t o Co 60 or are planning t h e switch. preparation of Kilocurie and Centicurie Co 60 sources. several hundred inhours for this purposee A t the present time Brookhaven i s working on the They have available E. BNL Production o f 8.0 day Iodine 131 Iodine 131 i s listled i n the Isotopes Catalog i n both separated and unseparated forms. Brookhaven can supply unseparated I 131. Since the separated form i s obtained ina purer state from fission products, and Brookhaven isnot set up t o perform this separation on a large scale, the separated.1 131 should usually be supplied from Oak Ridge. Brookhaven i s working on a I 132 (2.4 hour) generator which c m be very useful for nedical applications since sometimes the shorter half - lifeI 132

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i s preferred over 8,O day I 131, of a container of Te :132 obtrined from fission products; from the contained 77 hour Te 132, I 132 can be extracted by the customer, Briefly, the I 132 generator consists Since the fission product Te 132 i s obtained by chemical separation it w i l l be accompanie,c? by 30 hour Te 131 from which 8 day I 131 can be of I 131 to New York Hospitals were interrupted, Brookhaven could provide a temporary supply of' the 1 1 3 1 . radiation of TeO , producing the 30 hour Te 131 fromwhich 8 day I 131 could c m ,be obtained insufficient purity. (30 hour Te 131-325 min Te-8d I 131). If the Oak Ridge supply A larger supply would come from irBrookhaven i s continuing experiments to determine whether I 131 They are confident that they will be F, Isotopes of Higher Specific Activity than the Activity Specified in the Isotopes Catalon The Brookhaven reactor will permit higher specific activities by a factor of about 5 than i s possible in the Oak Ridge reactor. Still higher specific activities are available a t the Chalk River reactor A comgarison of production of Rb 86 inthe three reactors (Table 11) illustrates the advantages and limitations of each. Brookhaven can produce the standard Oak Ridge 100 mc per 6.5 g Rb2C03 activity in 1,4 days; O a k Ridge requires 6.2 days (calculated). The calculated saturation specific activity for 19,5 day Rb 86 i s 296 mc/gm Rb2C03 i n the Brookhaven reactor, witha neutron flux of 4 x 101~neutrons/cm'/sec.

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Production of 19,5 Day Rb 86 by Thermal Neutrons, Activities are Specified O a k Ridge Brookhaven Chalk River Activity per gram of Rb atoms f o r ir- 0.05 002 0 0 5radiation time equal 1 half-life Time required t o produce a 0,5 curie not at- not at- 1905 dqs Time required t o produce a 0.1 curie activTime required t o produce a 0.1- curie activactivity 0.015 cix-ie per gram Time t o transport sample t o Columbia U. 105 days 0012 days 1 2 days Activity arriving at Columbia U. 0.95 of 0.99 of 0.65 of original original original