[en] The NEMO collaboration started the construction of the NEMO 3 detector heaving as objective reaching a 0.1 eV limit on mass of the Majorana type neutrino. The project has been accepted by IN2P3 in 1994 and the construction started in 1995, with the planned completion date 1998. The chosen project was similar to that of NEMO 2 up to a scale factor of about 10; it is this scale factor as well as a calorimetric enclosure of almost 4 π and measuring times of the order of several years that will permit reaching the necessary sensitivity. It is provided for studies of enriched simples of up to 10 kg in the emitting isotopes. NEMO 3 will allow investigation of the different processes ββ0ν, ββ0νm and ββ2ν up to lifetimes of 10²⁵, 10²³ and 10²² years. Such long lifetimes impose a severe selection on all the materials used in the construction of the detector to avoid that the expected signal be polluted from spurious signals induced by the own radioactivity of the detector. Also, a perfect knowledge of the radiation background of the laboratory and its effects on the detector is required. The paper gives a general layout of the NEMO 3 detector and presents the CENBG contribution to the construction of calorimetric wells, to the measurements of radioactive materials purity by γ spectroscopy and the computation by simulation of the effect of neutrons on the detector

[en] The interest accorded to the decay of the sd shell nuclei is due to the high accuracy of the shell model calculations which allow by comparison between experiment and theory to obtain information on the weak and strong interactions and on the nuclear structure. In an experiment at the LISE3 facility of GANIL we produced the proton-rich isotope ²²Si by the fragmentation of a ³⁶Ar primary beam at 95 MeV/nucleon. After implantation in a detector telescope we studied the decay of ²²Si via a measurement of charged particles emitted during the decay. The most important β-delayed proton activity is observed at an energy of E_p = (1.99 ± 0.05) MeV with a branching ratio of (20 ± 2)%. The spectra allow also to determine the half-life of ²²Si to be T_1/2 (29 ± 2) ms. This results are compared with theoretical estimates and model predictions

[en] The predictions of neutron production induced by deuterons and protons with the LAHET code system are presented and compared. The incident energy of the projectiles, averaged neutron multiplicities, angular and energy distributions of emitted neutrons from different target materials and their further multiplication in the multiplying medium are considered as the most important parameters of our interest. The energy gain in the simplified sub-critical target assembly is estimated and compared for both of the incident particles as a function of their kinetic energy. (K.A.)

[en] An entirely new discrete levels segment has been created by the Budapest group according to the recommended principles, using the Evaluated Nuclear Structure Data File, ENSDF as a source. The resulting segment contains 96,834 levels and 105,423 gamma rays for 2,585 nuclei, with their characteristics such as energy, spin, parity, half-life as well as gamma-ray energy and branching percentage. Isomer flags for half-lives longer than 1 s have been introduced. For those 1,277 nuclei having at least ten known levels the cutoff level numbers N_m have been determined from fits to the cumulative number of levels. The level numbers N_c associated with the cutoff energies U_c, corresponding to the upper energy limit of levels with unique spin and parity, have been included for each nuclide. The segment has the form of an ASCII file which follows the extended ENEA Bologna convention. For the RIPL Starter File the new Budapest file is recommended as a Discrete Level Schemes Segment because it is most complete, up-to-date, and also well documented. Moreover, the cutoff energies have been determined in a consistent way, giving also hints about basic level density parameters. The recommended files are budapest-levels.dat and budapest-cumulative.dat. As alternative choices, the libraries from Beijing, Bologna, JAERI, Obninsk and Livermore may also be used for special applications. (author)

No abstract available

[en] The IAEA has recently completed two co-ordinated Research Programmes (CRPs) on The Development of Computer Models for Fuel Element Behaviour in Water Reactors, and on Fuel Modelling at Extended Burnup. Through these CRPs it became evident that there was a need to obtain data on fuel behaviour at high burnup. Data related o thermal behaviour, fission gas release and pellet to clad mechanical interaction were obtained and presented at the Technical Committee Meeting on Advances in Fuel Pellet Technology for Improved Performance at High Burnup which was recommended by the International Working Group on Fuel Performance and Technology (IWGFPT). The 34 papers from 10 countries are published in this proceedings and presented by a separate abstract. The papers were grouped in 6 sessions. First two sessions covered the fabrication of both UO₂ fuel and additives and MOX fuel. Sessions 3 and 4 covered the thermal behaviour of both types of fuel. The remaining two sessions dealt with fission gas release and the mechanical aspects of pellet to clad interaction

[en] Composite fuels or targets are considered as possible candidates for use in various applications (advanced fuels, burnable poisons, minor actinide incineration, increased plutonium consumption...). This paper summarizes the results of studies performed on UO₂/Gd₂O₃ composite fuels. The use of a burnable poison present within the fuel is being considered in order to increase the length of irradiation cycles beyond 12 months in French PWRs without increasing the concentration of soluble boron in the coolant. Furthermore, to extend the efficiency of the poison by slowing its gadolinium consumption down, a study was led using gadolinia in the shape of 300 μm diameter macro spheres, dispersed within the UO₂ fuel. The first stage of the studies involved manufacturing and characterizing the microstructure and sinterability of a UO₂ matrix 12 wt% gadolinia composite, with Gd₂O₃ macro spheres 300 μm in diameter. The second state consisted in comparing the conductivity of the composite to that of stoichiometric UO₂ and a godolinia-doped UO₂ containing the same proportion of gadolinium. Furthermore, composite reaction with water under PWR conditions has been studied. (author)

[en] In order to make a proper assessment of candidate materials for advanced high-burnup fuels, thermochemical studies of fuel materials have been performed. Using data from the ECN thermochemical database (TBASE), which has been updated and extended for the present work, the suitability of various advanced fuel materials and inert matrices is studied. Detailed thermodynamic equilibrium calculations are performed for Pu_0.42U_0.58O₂ and Pu_0.40U_0.60N for values of the burnup up to 200 MWd/kgHM. The formation of metallic phases, the pressure buildup and the stability of nitride or oxide phases is studied for each fuel type. The results for the chemical form of the solid fission products are given. The chemical aspects of the use of the inert matrix spinel (MgAl₂O₄) in combination with oxide fuel will be discussed. Experimental research on the compatibility of various types of inert matrices (nitrides, spinel) is in progress at ECN. (author)

[en] In this report, the Advisory Committee on Nuclear Safety (ACNS) presents the results of its study on how the system of the transport of radioactive material (TRM) in Canada is regulated, how it operates, and how it performs. The report deals with the transport of packages, including Type B packages which are used to carry large quantities of radioactive material, but not with the transport of spent nuclear fuel or with the transport of low-level historical waste. The ACNS has examined the Canadian experience in the TRM area, the regulatory framework in Canada with respect to the TRM some relevant aspects of training workers and monitoring compliance with regulatory requirements, the state of the emergency preparedness of organizations involved in the TRM and the process of updating present regulations by the Atomic Energy Control Board (AECB). As a result of this study, the ACNS concludes that the current Canadian regulatory system in the TRM is sound and that the TRM is, for the most part, conducted safely. However, improvements can be made in a number of areas, such as: determining the exposures of workers who transport radioactive material; rewording the proposed Transport Regulations in plain language; training all appropriate personnel regarding the AECB and Transport Canada (TC) Regulations; enforcing compliance with the regulations; and increasing the level of cooperation between the federal agencies and provincial authorities involved in the inspection and emergency preparedness aspects of the TRM. It is also noted that Bill C-23, the Nuclear Safety and Control Act, imposes a new requirement, subject to the Regulations, for a licence for a carrier to transport some types of radioactive material

[en] An inspection program for the detection of wall thinning due to erosion-corrosion (E-C), also known as flow accelerated corrosion (FAC), has been in place at Bruce B since 1 987. The purpose of this program is to prevent injuries to personnel or losses in production by monitoring the integrity of secondary side system- piping susceptible to this damage mechanism. Bruce B is a four unit CANDU Station, each unit 860 Mw net output with in-service dates of March 1985, September 1984, April 1986 and May 1987 for Units 5, 6, 7 and 8 respectively. To date two inspections have been completed in all units, with a third inspection performed in Units 5, 6 and 7. There have been few occurrences of significant wall thinning requiring the replacement of components or of system failures. This is an evolving program, and as it has matured it has been modified to reflect improvements in the inspection methods and the processing of the inspection results. (author)