PLANT TESTS ON THE DECOMPOSITION OF NITROUS OXIDE OVER A HEATED RHODIUM CATALYST

Plant scale tests were conducted to determine the feasibility of decomposing the nitrous oxide in dissolver off gases with a heated rhodium catalyst. The test results from two fixed bed reactors operating on off gases containing between 14.2 and 19.8 vol.% nitrous oxide show that the nitrous oxide content can be reduced to less than 0.05% with catalyst bed outlet at 1300 to 1500 deg F and space velocities at 472 to 700 hr/sup -//sup 1/. Rate constants appear to be comparable to those reported in the literature. Suggestions are made for the design of a permanent installation. (auth

PLANT TESTS ON THE DECOMPOSITION OF NITROUS OXIDE OVER A HEATED RHODIUM CATALYST

Plant scale tests were conducted to determine the feasibility of decomposing the nitrous oxide in dissolver off gases with a heated rhodium catalyst. The test results from two fixed bed reactors operating on off gases containing between 14.2 and 19.8 vol.% nitrous oxide show that the nitrous oxide content can be reduced to less than 0.05% with catalyst bed outlet at 1300 to 1500 deg F and space velocities at 472 to 700 hr/sup -//sup 1/. Rate constants appear to be comparable to those reported in the literature. Suggestions are made for the design of a permanent installation. (auth

International fuel cycle and waste management technology exchange activities sponsored by the United States Department of Energy: FY 1982 evaluation report

In FY 1982, DOE and DOE contractor personnel attended 40 international symposia and conferences on fuel reprocessing and waste management subjects. The treatment of high-level waste was the topic most often covered in the visits, with geologic disposal and general waste management also being covered in numerous visits. Topics discussed less frequently inlcude TRU/LLW treatment, airborne waste treatment, D and D, spent fuel handling, and transportation. The benefits accuring to the US from technology exchange activities with other countries are both tangible, e.g., design of equipment, and intangible, e.g., improved foreign relations. New concepts initiated in other countries, particularly those with sizable nuclear programs, are beginning to appear in US efforts in growing numbers. The spent fuel dry storage concept originating in the FRG is being considered at numerous sites. Similarly, the German handling and draining concepts for the joule-heated ceramic melter used to vitrify wastes are being incorporated in US designs. Other foreigh technologies applicable in the US include the slagging incinerator (Belgium), the SYNROC waste form (Australia), the decontamination experience gained in decommissioning the Eurochemic reprocessing plant (Belgium), the engineered surface storage of low- and intermediate-level waste (Belgium, FRG, France), the air-cooled storage of vitrified high-level waste (France, UK), waste packaging (Canada, FRG, Sweden), disposal in salt (FRG), disposal in granite (Canada, Sweden), and sea dumping (UK, Belgium, The Netherlands, Switzerland). These technologies did not necessarily originated or have been tried in the US but for various reasons are now being applied and extended in other countries. This growing nuclear technological base in other countires reduces the number of technology avenues the US need follow to develop a solid nuclear power program

Summary of national and international fuel cycle and radioactive waste management programs, 1984

Worldwide activities related to nuclear fuel cycle and radioactive waste management programs are summarized. Several trends have developed in waste management strategy: All countries having to dispose of reprocessing wastes plan on conversion of the high-level waste (HLW) stream to a borosilicate glass and eventual emplacement of the glass logs, suitably packaged, in a deep geologic repository. Countries that must deal with plutonium-contaminated waste emphasize pluonium recovery, volume reduction and fixation in cement or bitumen in their treatment plans and expect to use deep geologic repositories for final disposal. Commercially available, classical engineering processing are being used worldwide to treat and immobilize low- and intermediate-level wastes (LLW, ILW); disposal to surface structures, shallow-land burial and deep-underground repositories, such as played-out mines, is being done widely with no obvious technical problems. Many countries have established extensive programs to prepare for construction and operation of geologic repositories. Geologic media being studied fall into three main classes: argillites (clay or shale); crystalline rock (granite, basalt, gneiss or gabbro); and evaporates (salt formations). Most nations plan to allow 30 years or longer between discharge of fuel from the reactor and emplacement of HLW or spent fuel is a repository to permit thermal and radioactive decay. Most repository designs are based on the mined-gallery concept, placing waste or spent fuel packages into shallow holes in the floor of the gallery. Many countries have established extensive and costly programs of site evaluation, repository development and safety assessment. Two other waste management problems are the subject of major R and D programs in several countries: stabilization of uranium mill tailing piles; and immobilization or disposal of contaminated nuclear facilities, namely reactors, fuel cycle plants and R and D laboratories

Management of intermediate-level radioactive wastes in the United States

While used extensively, the term intermediate-level waste is not a clearly defined waste category. Assuming the ILW includes all radioactive wastes requiring shielding but not ordinarily included in a high-level waste canister, its major sources include power plant operations, spent fuel storage, and spent fuel reprocessing. While the volume is approx. 10/sup 2/ greater than that of high-level waste, ILW contains only approx. 1% of the radioactivity. Power plant waste, constituting approx. 87% of the waste volume, is generally nontransuranic waste. The other approximately 13% from fuel reprocessing is generally transuranic. Intermediate-level wastes fall into the general categories of highly radioactive hardware, failed equipment, HEPA filters, wet wastes, and noncombustible solids. Within each category, however, the waste characteristics can vary widely, necessitating different treatments. The wet wastes, primarily power plant resins and sludges, contribute the largest volume; fuel hulls and core hardware represent the greatest activity. Numerous treatments for intermediate-level wastes are available and have been used successfully. Packaging and transportation systems are also available. Intermediate-level wastes from power plants are disposed of by shallow-land burial. However, the alpha-bearing wastes are being stored pending eventual disposal to a geologic repository or by other means, e.g., intermediate-depth burial, sea disposal. Problem areas associated with intermediate-level wastes include: disposal criteria need to be established; fixation of organic ion exchange resins from power plant operation needs improvement; and reprocessing of LWR fuels will produce ILW considerably different from power plant ILW and requiring different treatment

Survey of waste package designs for disposal of high-level waste/spent fuel in selected foreign countries

This report presents the results of a survey of the waste package strategies for seven western countries with active nuclear power programs that are pursuing disposal of spent nuclear fuel or high-level wastes in deep geologic rock formations. Information, current as of January 1989, is given on the leading waste package concepts for Belgium, Canada, France, Federal Republic of Germany, Sweden, Switzerland, and the United Kingdom. All but two of the countries surveyed (France and the UK) have developed design concepts for their repositories, but none of the countries has developed its final waste repository or package concept. Waste package concepts are under study in all the countries surveyed, except the UK. Most of the countries have not yet developed a reference concept and are considering several concepts. Most of the information presented in this report is for the current reference or leading concepts. All canisters for the wastes are cylindrical, and are made of metal (stainless steel, mild steel, titanium, or copper). The canister concepts have relatively thin walls, except those for spent fuel in Sweden and Germany. Diagrams are presented for the reference or leading concepts for canisters for the countries surveyed. The expected lifetimes of the conceptual canisters in their respective disposal environment are typically 500 to 1,000 years, with Sweden's copper canister expected to last as long as one million years. Overpack containers that would contain the canisters are being considered in some of the countries. All of the countries surveyed, except one (Germany) are currently planning to utilize a buffer material (typically bentonite) surrounding the disposal package in the repository. Most of the countries surveyed plan to limit the maximum temperature in the buffer material to about 100{degree}C. 52 refs., 9 figs

Management of low-level radioactive wastes around the world

This paper reviews the status of various practices used throughout the world for managing low-level radioactive wastes. Most of the information in this review was obtained through the DOE-sponsored International Program Support Office (IPSO) activities at Pacific Northwest Laboratory (PNL) at Richland, Washington. The objective of IPSO is to collect, evaluate, and disseminate information on international waste management and nuclear fuel cycle activities. The center's sources of information vary widely and include the proceedings of international symposia, papers presented at technical society meetings, published topical reports, foreign trip reports, and the news media. Periodically, the information is published in topical reports. Much of the information contained in this report was presented at the Fifth Annual Participants' Information Meeting sponsored by DOE's Low-Level Waste Management Program Office at Denver, Colorado, in September of 1983. Subsequent to that presentation, the information has been updated, particularly with information provided by Dr. P. Colombo of Brookhaven National Laboratory who corresponded with low-level waste management specialists in many countries. The practices reviewed in this paper generally represent actual operations. However, major R and D activities, along with future plans, are also discussed. 98 refs., 6 tabls

International nuclear fuel cycle fact book. Revision 4

This Fact Book has been compiled in an effort to provide (1) an overview of worldwide nuclear power and fuel cycle programs and (2) current data concerning fuel cycle and waste management facilities, R and D programs, and key personnel in countries other than the United States. Additional information on each country's program is available in the International Source Book: Nuclear Fuel Cycle Research and Development, PNL-2478, Rev. 2. The Fact Book is organized as follows: (1) Overview section - summary tables which indicate national involvement in nuclear reactor, fuel cycle, and waste management development activities; (2) national summaries - a section for each country which summarizes nuclear policy, describes organizational relationships and provides addresses, names of key personnel, and facilities information; (3) international agencies - a section for each of the international agencies which has significant fuel cycle involvement; (4) energy supply and demand - summary tables, including nuclear power projections; (5) fuel cycle - summary tables; and (6) travel aids - international dialing instructions, international standard time chart, passport and visa requirements, and currency exchange rate

Summary of nuclear fuel reprocessing activities around the world

This review of international practices for nuclear fuel reprocessing was prepared to provide a nontechnical summary of the current status of nuclear fuel reprocessing activities around the world. The sources of information are widely varied

International nuclear fuel cycle fact book. [Contains glossary]

As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need has developed for a ready source of information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book was compiled to meet that need. The information contained has been obtained from nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECD/NEA activities reports; proceedings of conferences and workshops; and so forth. Sources do not agree completely with each other, and the data listed herein does not reflect any one single source but frequently is a consolidation/combination of information. Lack of space as well as the intent and purpose of the Fact Book limit the given information to that pertaining to the Nuclear Fuel Cycle and to data considered of primary interest or most helpful to the majority of users