[en] It is currently accepted that plutonium must be recycled on a large scale in thermal power reactors in the period starting in 1974 even though the ultimate long term market for plutonium will be in breeder reactors. To meet this schedule, the economics and technology of plutonium recycle must be demonstrated on a commercial basis by 1971-1972 if fuel suppliers are to be in a position to supply warranted plutonium recycle assemblies for delivery in 1974. United Nuclear Corporation is conducting a research and development program to provide the base of analytical and experimental data, necessary for supplying plutoniumbearing reload assemblies in light water reactors. This program includes activities in the following areas: 1. Evaluations of plutonium recycle utilization strategy and core design. 2. Critical experiments on PuO₂-UO₂ lattices. 3. Demonstration of plutonium recycle in a utility power reactor. A summary of progress and plans in these areas is given in the following sections.

[en] The importance for Pu-recycle for Germany lies in the specific fuel supply-situation. Pu-containing fuel is still made under relatively severe cost penalties. By optimisation of fuel distribution in light water lattices and by optimised fabrication technique this problem can be solved. Different fabrication routes are compared in their relative merits. The present status of the recycle Program in Germany is outlined. (author)

[en] The paper is subdivided into four parts: the first considers the exploitation of the energy potential of nuclear fuel in proven-type reactors and in advanced converters; the second describes ENEL's program for plutonium recycle in thermal reactors; the third discusses the availability of plutonium from ENEL's reactors; and the fourth provides a few comments on the economics of plutonium utilization. The main interest in recycling plutonium in thermal reactors pending commercial operation of fast reactors undoubtedly lies in the possibility of using plutonium as an alternate fuel in lieu of enriched uranium and of increasing exploitation of the source material. The paper gives the natural uranium exploitation indexes expressed in MWYe/ton of U_nat for a few proven-type reactors and converter reactors. The comparison of these indexes indicates that if plutonium recycling in thermal reactors is applied on a large scale, it will reduce natural uranium requirements for enriched uranium production by 30-40%. ENEL's program for the utilization of plutonium in thermal reactors is based on a research contract executed with EURATOM in 1966.

[en] Without plutonium utilization, overseas expenditure by the United Kingdom on uranium at present prices is anticipated to reach cM 150 - 200 by the end of the century. Recycling plutonium in thermal reactors would reduce this expenditure by 15%. However, the 250 MW(e) prototype fast reactor will be on power in 1971 and the first civil fast reactor should come on-line from about 1976 onwards, backed by an initial stockpile of some 12 Te plutonium. The consequence is a six-fold reduction in annual uranium requirements, by the end of the century, together with a substantial reduction in the present worth of expenditure on the nuclear power programme. Plutonium bearing thermal reactor fuel has already been supplied for irradiation in the prototype AGR, and in certain European reactors. A fuel plant for the manufacture of the plutonium fuel for the prototype fast reactor is nearing completion at Windscale, and this plant will also be used for-making further, plutonium bearing thermal reactor fuel. Recent emphasis in the neutronics of fast reactors has been on the alpha-value for Pu 239. The work is not yet complete but preliminary estimates have been made of the consequent effects on plutonium inventory and breeding gain. Irradiation tests on complete sub-assemblies of fuel pins under civil fast reactor conditions are continuing and have already demonstrated the feasibility of maximum burn-ups of 7,5% whilst single pins Have been successfully taken to burn-ups of 10%.

[en] This paper presents recent results from the USAEC's Plutonium Utilization Program conducted by Battelle-Northwest. The information will be presented at the Panel on Plutonium Utilization to be held by the International Atomic Energy Agency, September 2-6, 1968. A second paper ''United States Programs on Plutonium Utilization in Thermal Reactors'' presents a review of the plans of the program being conducted and, therefore, this paper will be primarily a status report on the technology of plutonium. The large number of water reactors purchased by U.S. utilities in the past few years will be put in operation in the late 1960's and early 1970's. These reactors will produce large quantities of plutonium and a plutonium excess for the United States is predicted for around 1973. Today it appears unlikely that fast reactors will develop soon enough to use this plutonium. Storing of the plutonium until fast reactors are developed does not appear economically feasible. Since the fuel cycle cost of the water reactors reflect a plutonium credit of 0.2 to 0.4 mils/Kwh, economic utilization of plutonium must be realized in order to effect this fuel cycle cost reduction. In the United States, water reactors will probably be the only reactors available in the 1970's in sufficient numbers to utilize the large quantities of plutonium available. Some plutonium will be required in the development of fast reactors and for loadings of the prototypes, but this is projected to be a small fraction of the total plutonium available in the 1970's. On this basis, the AEC's Plutonium Utilization Program objective is to develop by 1973 the base technology for safe and economic recycle of plutonium in thermal reactors, and more specifically in light water power reactors. The remaining technical uncertainties for plutonium recycle are primarily in the areas of fuels and physics. Consequently, these are the areas where the major research and development effort is being applied. These programs receive input from utilization studies which identify potential problem areas and incentives. The following sections of the report present recent results in fuels and physics development and plutonium utilization studies.

[en] The Panel on Plutonium Utilization held in Vienna from 2-6 September 1968 was the second one of its kind to be organised by the Agency. The first one on the use of plutonium for power production took place in December 1964. The attendance at the present Panel by participants and observers from 12 countries was an indication of the growing interest in the subject and the rapid progress which is being made in the field of plutonium use. The proceedings of the Panel (which to save time are being issued informally for the information of engineers and scientists engaged in work connected with plutonium), include review and topical papers on the development of plutonium utilization in various countries, statements on national programmes prepared by the respective participants , and the summary reports and recommendations of three working parties - each led by a rapporteur, as well as the general summary by the Chairman.

[en] The Plutonium Utilization Program (PUP) of the USAEC is being carried out by the Pacific Northwest Laboratory of Battelle Memorial Institute. The basic mission of the program has been to develop the- base technology necessary for the implementation of plutonium recycle in commercial power reactors. Hie program scope has been quite broad in the past, including plutonium fuels development, chemical reprocessing studies, physics of plutonium-enriched systems, and technical and economic optimization studies of plutonium-enriched reactors. More recently, the major efforts have been directed toward solving the immediate problems of utilizing plutonium as enrichment in refueling cycles in the present generation of H₂O moderated and cooled power reactors. This report summarizes the current and planned program activities. Another report prepared for the panel meeting ''Results from USAEC Plutonium Utilization Program Conducted by Battelle-Northwest'' presents detailed results and conclusions from the programs and therefore these will not be presented here. The major emphasis of the program are on physics and fuels developments.

[en] Overview of the French program, in which the proposed fast reactor fully absorb the Plutonium produced by the reactors heat until 1978. However, problems concering U Pu elemtents, namely performance, manufacturing costs and reprocessing have been studied in France. For the moment a program for recycling plutonium in thermal reactors is premature.

[en] This paper summarises the work done in India in the field of physics and economics of plutonium utilization. Plutonium recycle was considered in Tarapur Atomic Power Project and Rajasthan Atomic Power Project and the results obtained are presented in this paper. A short description of the plutonium laboratory being constructed in India i s also presented. (author)

[en] This paper reports about the main activities performed or under way in Italy in the field of plutonium utilization by ENEL (Italian State Electricity Agency) and CNEN (National Committee for Nuclear Energy).