STANDARDS

The standards and guides we use to control the release of radioactive materials from AEC installations are derived from recommendations of the Federal Radiation Council, the International Commission on Radiological Protection, and the National Committee on Radiation Protection and Measurement.

The Federal Radiation Council is a statutory body composed of Cabinet-level officers; it recommends to the President for approval guidance to be applied by all Federal agencies and their contractors. The recommendations of the other two organizations are stated as maximum permissible concentration-MPC-of radionuclides in both air and water. However, the primary standard is a radiation dose limit from which the secondary-standards MPC-are derived by calculation.

In general, no discard or dispersion of radionuclides is permitted solely on the grounds that the level of radioactivity is below existing guidelines and can therefore be considered harmless. On the contrary, a reasonable effort must first be made to remove as much radioactivity as can be accomplished within practical limits.

SOLID WASTES

Let me now describe briefly our operating experience in solid waste disposal. Prior to 1960, AEC licensees and other Government agencies used commercial sea-disposal services for their solid low-level wastes. In May 1960, the Commission began accepting solid low-level wastes for burial at Oak Ridge, Tenn., and the National Reactor Testing Station in Idaho.

This service was discontinued in August 1963, after commercially operated burial grounds had been established. Approximately 300,000 cubic feet of low-level wastes were buried at AEC sites under the interim burial program.

There are now five commercial burial grounds in the United States which are used for disposal of low-level solid radioactive waste; these are operated under license from either the AEC or an agreement State, depending on the location of the site.

An agreement State is one which assumes certain regulatory responsibility for the use of atomic energy materials by agreement with the Commission pursuant to section 274 of the Atomic Energy Act. Land used for the purpose of disposing of low-level waste received from others is required, by regulation, to be owned by either the Federal or a State Government so that it may be dedicated exclusively for burial of radioactive waste and maintained in perpetuity.

Commercial burial grounds are located at Richland, Wash.; Beatty, Nev.; Sheffield, Ill.; Morehead, Ky.; and West Valley, N.Y. Through June 1969 a total of approximately 3 million cubic feet of low-level wastes were buried. The volume of low-level solid wastes to be disposed of annually by burial is estimated to reach 1 million cubic feet by 1970, 3 million cubic feet by 1975, and 6 million cubic feet by 1980. One million cubic feet of solid waste requires about 15 to 20 acres of burial space.

Among the criteria for obtaining a license to operate a radioactive waste disposal site is the requirement that the geological and hydro

logical characteristics of the site be such that the radioactive waste will not enter potable water supplies or the biosphere.

Test wells are located around the site periphery to monitor against possible migration of radioactive materials. Trenches in which the radioactive material is placed are required to be backfilled, mounded, and marked to identify the completed trench and the quantities of materials contained therein. The commercial operator is required to maintain complete records of the quantities of radioactive materials buried.

AEC's solid wastes have been buried in unlined earthen trenches and backfilled. Wastes are sorted and are buried in separate locations according to the type of radioactivity involved. Sites are marked and records are maintained as to quantities and types of materials buried.

In most cases, wastes are packaged in cardboard, wood, or metal containers before burial. Very highly contaminated process equipment is decontaminated as much as practical before burial. Wastes containing greater than trace amounts of long-lived alpha activity are buried in wood, concrete, or steel containers.

Wells to the ground water table in and around the burial grounds are sampled routinely to detect any radioactivity which might migrate from buried waste. In no case has activity been found in the ground

water.

HIGH-LEVEL RADIOACTIVE WASTES

As indicated above, essentially all the radioactive wastes generated at nuclear power reactor sites fall into the low-level category. Highlevel wastes, on the other hand, are produced in the nuclear fuel reprocessing plants during chemical processing of used fuel elements to recover any remaining unused uranium for future use.

Nuclear fuel elements are designed to possess a high integrity and capability of retaining the fission products formed during reactor operation. They, of course, also retain any unused uranium (which has not undergone fission) and plutonium, a byproduct of the operation, which are the primary objects of the recovery operation at the reprocessing plant.

After their useful life, these fuel elements are removed from the reactor and shipped intact to the reprocessing plant where chemical separation of the radioactive wastes from the valuable uranium and plutonium takes place.

Considering that nuclear material costs represent about 15 percent of the total nuclear fuel cycle cost, it is not difficult to understand why the Commission and the nuclear power industry have invested millions of dollars to fuel reprocessing plants. As a general rule, whether it be nuclear fuel used in an AEC-owned production reactor or a commercial power reactor, economics will usually justify recovery of the unconsumed uranium or other fissile material that may be present.

RECOVERY

It should be recognized that after recovery of these valuable materials there is still a need for the safe and permanent storage of the remaining fission products which are generated as radioactive by

The Atomic Energy Commission is also recovering certain specific radioactive isotopes from the collected fission products in the high-level radioactive wastes in storage at our Hanford site in Washington. These high-level wastes are processed to remove approximately 90 percent of the contained cesium and strontium.

This is done so that the wastes can be concentrated from liquids to "salt cakes" in the waste tanks. If the cesium and strontium were not removed prior to concentration, it would probably entail greater expense and longer periods of time before solidification could be effectively carried out. The cesium and strontium removed from the wastes will be converted to a safe form for long-term storage.

Processes have been developed and tested for the recovery of large amounts of cesium, strontium, cerium, and promethium. At least one commercial firm is considering the recovery of the nonradioactive rhodium from the aged stored liquid wastes. The palladium and technetium fractions which are separated along with the rhodium may also find some applications.

Most of the applications which would make use of large quantities of recovered fission products can be satisfied by other methods, in most cases at less cost. Thus, there is no strong economic incentive to recover the fission products at this time. In 1965, Isochem, a company owned by U.S. Rubber and Martin Marietta, applied for a license to construct and operate a plant at Hanford for converting fission products to usable forms. However, due to delays in the development of a market, this plant was not built.

These special radioactive materials are removed from waste solutions by such techniques as ion exchange, solvent extraction, and precipitation as insoluble salts. For example, at Hanford, cesium is removed from the wastes by passing it through a tank filled with a special zeolite. After the zeolite bed is loaded with cesium during the course of operations, it is regenerated and reused to recover more cesium.

Generally speaking, this recovery equipment is similar to a home water softener but, because of the complications due to radioactivity, its design, installation, and operation is much more complex and costly than that of a water softener. Because of the radioactivity in the wastes, special precautions are taken to protect operating personnel from radiation and to preclude accidental releases of radioactivity to the environment.

Except under special circumstances, such as the current recovery operation at Hanford, removing the radioactive materials from stored wastes is not a promising waste management technique. It is not feasible, either technically or economically, to remove enough of the radioactive products from the waste to allow the direct release of the remainder to the environment.

Thus, instead of a single highly radioactive waste to manage, there would be, after separation, several highly radioactive fission product fractions plus the original waste, each requiring special attention.

The high-level wastes, which are generated at present at AEC production sites and at the Nuclear Fuels Services site, a commercial facility located in New York State, have concentrations of radioactivity in the range of hundreds up to tens of thousands of curies per gallon of solution.

TANK STORAGE

The high-level wastes which have been generated since the beginning of the atomic energy program have resulted in a stored volume of about 80 million gallons, all of which is stored in specially designed underground tanks and intensively monitored. These tanks have been made of carbon or stainless steel.

More than 20 years' experience with the present method of handling highly radioactive liquid wastes from fuel reprocessing by storage in such tanks has shown it to be a practicable means of interim handling. Nearly 200 such underground tanks have been used throughout the Atomic Energy Commission complex.

While current tank storage practices have been successful in preventing significant quantities of radioactive materials from escaping to the environment, these operations require continual surveillance and periodic tank replacement.

This need for surveillance, as well as the necessity of transfer of liquid wastes from tank to tank over periods of hundreds of years, has been a compelling factor for our extensive research and development programs directed at the conversion of high-level liquid waste to a solid form and the ultimate storage of the solid-waste materials in selected geologic environments.

The principal objectives of the Atomic Energy Commission's continuing research and development program is to improve our technology to engineer systems for the control of radioactive wastes. In general terms, AEC's waste management R. & D. program falls into two categories: the control of low-level and high-level wastes.

The large volumes of low-level gaseous and liquid wastes which evolve during the course of operating reactors and other nuclear facilities are treated and discharged; the large volumes of low-level solid waste are stored in controlled areas as described earlier. The much smaller volumes of high-activity wastes generated during the reprocessing of irradiated nuclear fuels are treated and placed in interim storage.

Significant progress and accomplishments have been achieved during the past 15 years in developing satisfactory waste management systems for both categories of waste. Many alternate waste treatment and disposal methods have been studied on a laboratory and engineeringdevelopment scale.

Since the middle 1950's several processes for conversion of liquid waste to stable solids have been investigated. These processes include the use of fluidized beds, a rotary ball kiln, ceramic sponges, heated pots, and radiant-heated spray columns.

The addition of glass-forming materials for the purpose of providing a relatively insoluble final product has also been intensively studied. The fluidized-bed, pot, spray, and phosphate-glass processes have undergone extensive engineering development during the past several years, and the fluidized-bed process has been in routine use at the National Reactor Testing Station in Idaho since 1963 for the reduction to solid of fuel reprocessing waste.

The success, over the years, of the Commission's waste management program is illustrated by the excellent effluent control record which has been achieved by the industry and AEC contractors. AEC produc

tion and research facilities and large commercial nuclear powerplants generally limit releases of radioactive materials to the environment to concentrations which are only a small fraction of internationally accepted radiation protection standards.

RESEARCH AND DEVELOPMENT

Highlights of the R. & D. program may be summarized in the following general way:

1. Advanced low-level waste treatment and disposal technology involving the use of evaporation, ion exchange, foam separation, electrodialysis, water recycle, and asphalt solidification has been developed. This technology is now being used in the design of commerical power reactor and fuel reprocessing waste management facilities.

2. The disposal of radioactive waste slurries by hydraulic fracturing of shale has been demonstrated with an engineering-scale pilot plant at Oak Ridge National Laboratories. This technique, which has been used by the petroleum industry, consists of injecting a waste-cementclay mixture under high pressure through a slotted well casing into an impermeable formation at depths of, in the case of ORNL, 700 to 1,000 feet.

A hydrofracturing plant was placed in operation at Oak Ridge during 1966 for the disposal of evaporator concentrates; the use of this disposal method at other sites is now under study.

3. The Waste Calcining Facility at the National Reactor Testing Station in Idaho became the world's first plant-scale facility for converting actual high-level radioactive wastes to a safer, solid form in December 1963. This plant has demonstrated the use of the fluidizedbed process during the past 6 years, and has processed approximately 1.4 million gallons of aluminum nitrate waste and about 320,000 gallons of zirconium-type waste.

Through July 1, 1969, the volumes of solid waste are about 18,000 cubic feet of alumina solids and 5,800 cubic feet of zirconium-type solids, respectively. An average volume reduction of approximately 10 has been obtained since plant startup, and the resulting solids are being stored in stainless steel bins in underground concrete vaults.

4. Additional technology suitable for solidification of power reactor fuel reprocessing high-level waste has reached the engineering-scale demonstration phase with a "hot"-pilot plant placed in operation at the Commission's Laboratories in Hanford, Wash., in November 1966. Approximately 29 million curies of high-activity waste have been solidified in 24 process runs to date, with a maximum of 3.6 megacuries-3.6 million curies-being converted and deposited in a single pot.

The pilot-plant program is now in its culminating phase with the solidification processes being demonstrated on simulated waste compositions from advanced, high-radiation exposure fuels. Results of these R. & D. programs are being provided to industry on a continuing basis for use in the design and construction of solidification systems for commercial processing plants.

5. Extensive laboratory and field research has been carried out on the disposal of different types of radioactive waste effluents-solids, liquids, and gases in various shallow and deep geologic media, such as shales, sandstones, crystalline rock, and salt formations.

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