[en] The aim of this work is to give a review of the methods and the problems encountered in measurements in 'input accountability tanks' of irradiated fuel treatment plants. This study was prompted by the conviction that more and more precise techniques and methods should be at the service of safeguards organizations and that ever greater efforts should be directed towards promoting knowledge of them among operators and all those general area of interest includes the nuclear fuel cycle. The overall intent is to show the necessity of selecting methods which produce measurements which are not only more precise but are absolutely reliable both for routine plant operation and for safety checks in the input area. A description and a critical evaluation of the most common physical and chemical methods are provided, together with an estimate of the precision and accuracy obtained in real operating conditions

[en] The normal operation releases from the most important fuel cycle facilities are assessed for an LMFBR fuel cycle, recycling or not recycling self generated by-product actinides in a 400 years lasting fast breeder power economy. The data compared are activity, inhalation and ingestion hazards and dose rates derived from the hazards

[en] Gamma ray buildup factors are calculated with the transport code PIPE for source energies from 0.5 to 4 MeV in a barytes concrete of density 3.3 gr/ccm. The results are compared with those of the moments' method interpolated with effective z-values

[en] Plane isotropic buildup factors are calculated for LiH, Li, Be, C, and H₂O, for source energies from 50 keV to 8 MeV and penetrations 1 to 20 mfp. The H₂O values are compared with those of other authors. Low source energies (<=100 keV) in Li and LiH lead to buildup factors of some millions at deep penetration. - In an annex, the B-factors for low source energies are given also for Al and Fe

[en] Gamma ray buildup factors are calculated with the transport code PIPE for source energies up to 4 MeV in different glass-plus-lead glass shields (densities 2.53 resp. 5.20 gr/ccm)

[en] The Fast Breeder Reactor fuel performance during normal operating conditions is analyzed in this paper by means of a semianalytical model making use of some physical simplifying assumptions. In particular the fuel densification process and the pin temperature distribution are treated by coupling a three constant density zones model with the analytical solution of the monodimentional heat conduction equation. Fuel and clad swelling, fuel thermal conductivity and fission gas release are obtained from given HEDL empirical correlations while a very simplified treatment of the fuel-clad gap conduction and no stress analysis calculations are performed. The fast running computer code developed from this model (RESTRUC) is adopted as 'module' of steady state pin performance in the European Accident Code (EAC), a large computer system developed for the analysis of Hypothetical Core Disruptive Accidents (HCDA) in Fast Breeder Reactors (FBR). Various test cases and in particular the calculation by means of the EAC adopting RESTRUC of the steady state of a BOEC core for a large FBR have shown satisfactory results in comparison with other codes performing the same type of calculations

[en] Second joint annual report of the work performed on the testing and evaluation of materials for immobilizing high activity waste under Community contracts. At Marcoule, active block samples containing HAW from the Marcoule reprocessing plant were cast to the specification of five of the six original reference samples and leach tested at ambient temperature. Phosphate glass -bead samples produced by the Gelsenberg/DWK PAMELA process- were included in the test programme at HMI-Berlin and UKAEA Harwell. Leaching tests of inactive samples with leachants of various pH-values, with ionized water and with natural water compositions representative of certain repository conditions (salt, clay and granite) were added to the Harwell programme. The studies of radiation and thermal effects and the investigation of devitrification phenomena, started in 1977, continued, as samples reached annealing times of 2400 h and doses 4 x 10¹⁷ dpg. The results achieved have so far confirmed most of the favourable preliminary assessments of glass based solidification products. At this stage the programme aims primarily at the understanding of physical and chemical phenomena rather that at verification under realistic waste storage and disposal conditions

[en] Major components of combustibles PCM arising from typical fuel reprocessing operations are: PVC, rubber, polyethylene and cellulosic materials. Small-scale studies of inert atmosphere pyrolysis and chemical analysis of products were effected. These chemical studies were supplemented by bench-scale process experiments. The programme confirmed the general process feasibility, but provided insufficient information for an engineering appraisal. Larger scale experimentation is necessary to determine the effects of heat and mass transfer within bulk waste upon reaction rate and properties of the products. Equipment and experimental pyrolysis runs are described. Reactor performance, off-gas properties, char properties and char oxidation are given and long term programmme is planned

[en] The increasing number of power station and of the total operating time has given new emphasis to the study of contamination mechanisms and decontamination methods. It seemed then worthwhile to prepare a review of the state of art. Two chapters are devoted to the contamination mechanisms and to the parameters of the water chemistry which influence the contamination. Two other chapters describe the composition and structure of the oxide films and their radioactivity content. The last four chapters are devoted to the different types of decontamination techniques and on the possible methods of contamination prevention

[en] STEAG Kernenergie GmbH is so far the only firm commercially to condition radioactive bead ion exchange resins by embedding in polystyrene resins. The objective of the work reported here was to study and develop methods for immobilization of other reactor wastes in plastic resins. Comparison studies on high quality cement however showed favourable results for cement with respect to process safety and economy. For this reason STEAG interrupted its work in the field of resin embedding after about one year. The work carried out during this period is surveyed in this report, which includes a comprehensive literature study on reactor wastes and their solidification in plastic resins as well as on regulations with regard to radioactive waste disposal in the member states of the European Communities