IN ORDER TO Supply radioisotopes for Manhattan Project installations about the country during World War II, completely new chemical technology for handling large amounts of radioactive materials had to be developed. Many problems now easily handled then were major, complex matters. As new radioisotopes were discovered and new techniques found for separating and purifying them, better instruments for detection and measurement of radiation were developed. Research was done to develop ways to perform tasks never before attempted; and the work has continued, under the Commission with radioisotope separation techniques, equipment and instrument designs, and source fabrication technology improving steadily to yield increased production, greater safety, and higher quality at lower costs.

PRODUCTION

Research and development has increased the number of reactor-produced radioisotope products available from only two in 1946 (carbon 14 and iodine 131) to more than 100 in 1959. The techniques of manufacturing, handling, and shipping large amounts of highly purified radioisotopes have been developed to the point where most of the operations are as routine as those of other industries.

A primary objective of the Commission's isotope program is to devise techniques for producing all reactor-produced radioisotopes with half-lives of sufficient length to permit distribution. Continuing efforts are aimed at increased radiochemical purities and higher specific activity of radioistopes distributed.

Radioisotopes are produced in a reactor, then purified and prepared for shipment, usually in solution form. Fission products, processed radioisotopes, special products such as cobalt 60 and cesium 137 teletherapy and radiographic sources, zirconium-tritium targets, beta applicators, gamma irradiation devices, and specially compounded radioisotope preparations are available from Oak Ridge.

Multicurie Pilot Plant

Fission products. A multicurie fission products pilot plant at Oak Ridge, designed to demonstrate the processing of long-lived radioactive fission products, started preliminary operations on August 7, 1958. This facility is being used to isolate large quantities of radioisotopes for military and industrial applications.

The plant, costing some $2.2 million, is equipped for the separation, purification and sources fabrication of kilocurie quantities of such isotopes as cesium 137, strontium 90, promethium 147, cerium 144, and technetium 99. However, it is primarily a process development facility that is providing technology and operating experience for achieving higher recovery efficiencies and lower operational costs. It has been improved with additional shielding and equipment to expand the original design capacity because of the high demand for fission products in multicurie amounts. Further installation of equipment is under way.

Radiochemical processes related to fission product removal and recovery from reactor

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fuel process effluents are also being developed at Hanford, Savannah River and the National Reactor Testing Station at Idaho.

The following sections give a brief summary of the fission products available from Oak Ridge in kilocurie quantities.

One of the most important long-lived gamma emitting isotopes found in the byproducts of nuclear fission is cesium 137. It is chemically recovered as dry cesium chloride powder, then compressed to form a compact pellet with a density of 3.3 grams/cc that contains about 27 curies of cesium 137 per gram of solid. The plant has the potential capacity to produce 200,000 curies of cesium 137 annually.

The best long-lived, high energy beta emitter than can be made available in large quantities is strontium 90. Its 0.6 Mev beta radiation,

coupled with 2.2 Mev beta radiation from its yttrium 90 daughter, makes strontium 90 an extremely useful power source. The strontium 90 is recovered as a strontium fluoride, compressed into pellets having a density of 4.2 grams/cc that contain about 30 curies of strontium 90 per gram of solid. About 200,000 curies of strontium 90 can be produced annually.

A number of beta and gamma radiations make cerium 144 a potential power source. The high 2.97 Mev beta rays from the praseodymium 144 daughter are also suitable for radiography. The cerium 144 is recovered as cerium oxide and sintered at 1500° C. to get a dense 5.5 gram/cc ceramic pellet containing about 300 curies of cerium 144 per gram of solids. The production capacity for cerium 144 is about 2,000,000 curies a year.

Promethium 147 is a beta emitter with a maximum energy of 0.223 Mev, has a half-life of 2.6 years, and does not occur naturally on earth. It is available in the form of promethium oxide pellets having a density of approximately 5 grams/cc containing 400 curies per gram of solids. The plant can produce 400,000 curies of promethium 147 annually.

The low energy, pure beta emission of very low specific activity technetium 99 is not released at a rate sufficient to make it attractive for the conventional applications of radioactivity. However, it has the unique chemical property of remarkable inhibition of the corrosion of soft iron in neutral aqueous solutions. Mild carbon steels may be protected by as little as 5 parts/million of technetium (5 x 105M KT.O.) in aerated distilled water at temperatures up to at least 250° C. Technetium does not occur naturally on earth, but gram quantities are available from the plant.

The relatively long half-life, 10.27 years, and the decay to rubidium by emitting beta particles and gamma radiation enhances the usefulness of krypton 85. It is finding increasing use for activating phosphors in self-luminous light sources. It is cheaper, easier to work with, and causes less deterioration of the phosphor than naturally occurring alpha-emitting radium and polonium. In response to industrial requests for larger quantities of krypton 85, the Commission has increased the availability of this radioisotope for civilian uses to 100,000 curies a year.

SPECIAL MATERIALS AND SERVICES

Oak Ridge National Laboratory

In addition to making available processed radioisotopes and fission products, Oak Ridge National Laboratory performs service irradiations, neutron activation analyses, and handles some disposition of waste material for radioisotope customers.

Reactor service irradiations and special materials and services are available also from the

Argonne National Laboratory, Brookhaven National Laboratory, and the National Reactor Testing Station. These Commission-owned services are made available for private use if the desired work cannot be conducted in commercial facilities, and if it will not interfere unduly with Government programs. Charges cover full cost. Requests for the use of Commission facilities are made directly to operating contractors.

Argonne National Laboratory

The Argonne National Laboratory, operated for the Commission by the University of Chicago, provides facilities and services especially useful to Midwest institutions and enterprises requiring high specific activities, isotopes with short half-life, or irradiation of special objects. This service supplements isotope production activities at Oak Ridge.

Brookhaven National Laboratory

Brookhaven National Laboratory, operated for the Commission by Associated Universities, Inc., has several facilities for radioisotope production or research which can be made available under certain conditions to outside research organizations. These other facilities include a 60-inch Cyclotron, a gamma ray irradiation facility, and a hot chemistry laboratory.

Brookhaven National Laboratory produces special process radioisotopes, and is an alternate supplier in cases where short half-life radioisotopes are required, or where items are not available from Oak Ridge.

National Reactor Testing Station

The Materials Testing Reactor (MTR) operated for the Commission by Phillips Petroleum Co., at the National Reactor Testing Station is used by both Commission laboratories and private industry for irradiation work; however, emphasis is placed on experiments furthering the reactor development program. Priority is given to experiments sponsored by

PRICING

Commission prices for radioisotopes have decreased steadily since 1947. In calendar year 1958, total Oak Ridge sales revenues declined slightly while the quantity of radiation shipped increased by 37 percent. Price reductions were accomplished through improvements in processing methods as well as through efficiencies and a larger sales volume.15

The price for high specific activity cobalt, for example, has been reduced more than 50 per

cent.

When high specific activity cobalt 60 became available in 1953, the price was set at $75 per curie for the first two curies; and $7.50 per curie for each curie in excess of two. In October 1954, the price was reduced to $50 per curie for the first two curies, plus $9 or $10 per curie, depending upon the specific activity, for quantities in excess of two curies. In 1957, the prices on high specific activity cobalt again were reduced, to $4 or $5 per curie, depending on the activity, with 15 percent discounts on quantities between 5,000 and 25,000 curies and a discount of 30 percent for quantities greater than 25,000 curies. Today, high specific activity cobalt 60 can be obtained for as low as $3.50 per curie.

In the early 1950's, cesium 137 cost $500 per curie. This figure then was reduced in 1956 to a sliding schedule of $10 to $25 per curie depending on the quantity purchased. Today, cesium 137 prices range, depending on the quantities, from $1 to $2 per curie.

In April 1958, the Commission reduced prices. on other fission products available from the Fission Product Pilot Plant at Oak Ridge National Laboratory to an average of less than

15 Information on prices may be obtained on request as follows: Catalog and price list, radioisotopes, special materials and services, Radioisotopes Sales Department, Oak Ridge National Laboratory, Oak Ridge, Tenn.; polonium and plutonium sources, Mound Laboratory, P.O. Box 32, Miamisburg, Ohio; Research reactor facility, irradiation service, and radioisotopes, Isotopes and Special Materials Group, Brookhaven National Laboratory, Upton, Long Island, N.Y.; irradiation services, Special Materials Department, Argonne National Laboratory, Lemont, Ill.; irradiation services, Materials Testing Reactor. Atomic Energy Division, Phillips Petroleum Co., National Reactor Testing Station, Idaho Falls, Idaho.

10 percent of those formerly in effect for promethium 147, cerium 144, strontium 90 and technetium 99.

Also, in July 1953, a quantity discount was established for carbon 14. The price was reduced from $36 to $32 per millicurie on single shipments of 200 millicuries or more. For quantities of less than 200 millicuries the price remained the same. In July 1956, this schedule was further reduced to $28 per millicurie for quantities less than 200 millicuries and $22 per millicurie for 200 millicurie and greater quantities. The carbon 14 price was reduced June 1, 1959, to $13.00 per millicurie or fraction of a millicurie.

Between 1946 and 1952, isotopes for cancer research were distributed with payment only of shipping charges by the user. In 1952, isotopes for cancer research were made available at about 20 percent of list price, and in 1955, broader program was established under which isotopes were made available at about 20 percent of list prices for all life science research in the United States.

a

The Commission, in establishing prices took cognizance of the criteria in the Atomic Energy Act of 1954 that its prices shall be on such equitable basis as in its opinion: (a) will provide reasonable compensation to the Government for such material, (b) will not discourage the use of such material or the development of sources of supply of such material independent of the Commission, and (c) will encourage research and development.

DISTRIBUTION

When the radioisotope distribution program began, the Commission was the nation's primary agency for developing the availability of isotopes, isotope compounds, radiochemical services, special type of sources, instrumentation, and safe handling devices. The Commission through the years has encouraged private enterprise to supply these services.

The continuing growth of radioisotope utilization is demonstrated by table I. These data are based upon sales and on curies shipped