[en] To increase the device reliability and structural material economy the working section of the sample charging device for in-pile testing is produced in the form of a holder with a sloping sided cap fixed on it. A sample is placed to the cap. Under the chamber charging during the inpile irradiation testing the sample is placed to the cap and then supplied to the chamber through the charging well using a special rod. By means of rod rotation the cap with sample is placed between the punches and fixed. The charging device is fully with drawn from the unit and the charging well is sealed. The cap wall icline is chosen with regard to the sample non-overturning condition, therefore the sample always occupies the vertical position in the cap

No abstract available

No abstract available

[en] Published in summary form only

[en] Published in summary form only

[en] This paper describes the application of probabilistic safety assessment for the design of a heavy water isotope production research reactor in China. The study provided the basis for decisions on design changes and discovered deficiencies in the design and in basic parameters including the large equivalent reactivity of the shim control rod. Among the main insights it was found that the emergency ventilation system is a most important engineered safety system to control outside doses and that the shim control rod ejection is so serious that it has to be avoided in every possible way. (author). 1 fig., 1 tab

[en] Aimed at maximization of isotope production some optimization aspects of degenerated isotope irradiation modes in a nuclear reactor are analyzed under the circumstances of counteracting isotope burnup and production processes in different neutron spectra ranges in the case when the energy dependence of the cross sections differs substantially for different isotopes. The analysis is conducted in the two-group approximation (thermal and resonance neutrons). An optimal solution of the equation describing the time dependence of isotope concentration is obtained. The specific features of the optimization problem are demonstrated on the example of a simple three-link chain. The problem considered is characterized by the fact that at the optimal regime not absolute time dependences of each range of the neutron spectrum are determined, but only relative interdependence between different energy ranges

[en] We propose a method to improve the impact energy of ions implanted into the interior sidewalls of cylindrical specimens during plasma immersion ion implantation. Our idea is based on a zero potential conductive auxiliary electrode positioned at the axis of the implanted cylindrical bore. We calculate the structure of the ion-matrix sheath in an infinitely long cylindrical bore with an auxiliary electrode and analyze the dependence of the radius of the auxiliary electrode on the electric field in the bore. Our results show that the auxiliary electrode improves significantly the distributions of the potential and the electric field inside the cylindrical bore. In addition, because the auxiliary electrode improves the potential drop from axis to sidewalls of the bore and introduces an electric field component which does not vary when the ions are implanted into the sidewalls, the impact energy can be improved in a cylindrical bore during plasma immersion ion implantation. copyright 1996 American Institute of Physics

[en] The fabrication of the isotopes used in nuclear medicine is mainly made in research reactors. Furthermore reactors are necessary for the production of Mo⁹⁹ whose daughter nucleus Tc⁹⁹ is used in 80% of medical diagnostics worldwide. Today about 50 reactors produce medical radionuclides but only 15 of them, the most powerful ones, supply the international market. As soon as the fifties, CEA has been producing radionuclides, first in the Zoe reactor and then unceasingly in its successive experimental reactors: EL2, EL3 in Saclay, Melusine, Siloe in Grenoble and Osiris and Orphee again in Saclay. The Jules Horowitz reactor under construction in Cadarache will take over in a few years. Radiochemistry plays an important role in the extraction and purification of the radionuclide. (A.C.)

[en] The main tools for the production of radionuclides for medicine are nuclear reactors and accelerators especially cyclotrons and linear accelerators. About 30 reactors over the world share isotope production. Two types of reactors are used to produce radio-nuclides: experimental reactors and neutron source reactors. In a reactor, radionuclides are produced through either fission reactions or neutron activation reactions. For instance the Technetium-99 whose daughter isotope Molybdenum-99 is used in scintigraphy is produced through the fission of Uranium-235 target, its fission yield being over 6%. The most important experimental reactors having a radioisotope production program are HFR (45 MW, The Netherlands), BR2 (100 MW, Belgium), NRU (135 MW, Canada), MARIA (30 MW, Poland), LVR-15 (10 MW, Czech Republic), SAFARI-1 (20 MW, South-Africa) and FRM-II (20 MW, Germany). Neutron source reactors are less powerful a few MW and produce radionuclides through neutron activation reactions. In France 2 neutron source reactors produce radionuclides for medicine: the Orphee reactor (14 MW, at Saclay) and the RHF (58 MW at Grenoble). (A.C.)