[en] The research and development activities of the High Pressure Physics Division during the period October 1993-March 1996 are reported in the form of collection of papers presented in journals, conference proceedings and abstracts in conferences and Bhabha Atomic Research Centre (BARC) technical reports. The report is organised in two sections: (A) High Pressure Physics Division, and (B) Seismology Section. A list of staff members is enclosed at the end

[en] The first series of experiments at the FOBOS detector, using beams of the U-400M cyclotron of the Flerov Laboratory of Nuclear Reactions, was devoted to few-fragment decays of equilibrated systems. To exclude deep inelastic collisions or quasifission as sources of massive fragments, hot heavy nuclei were produced in the very asymmetric reactions ⁷Li(43 AMeV)+ ²³²Th, ¹⁴N(34 AMeV)+¹⁹⁷Au, and ¹⁴N(53 AMeV)+¹⁹⁷Au, ²³²Th. Two- and three-fragment events were analysed on the base of masses and velocity vectors measured independently for each fragment. Fragment mass distributions as well as total kinetic energies were studied for an excitation energy range of 100-500 MeV. For events with three fragments of comperable size neither the assumption of two sequential independent fission acts nor a multifragmentation-like scenario can reproduce the data. Agreement is achieved if these three-fragment decays are characterized by a collinear intermediate state followed by two scissions separated by no more than 200 fm/c, a very short time scale compared with usual saddle-to-scission intervals. (orig.)

[en] Reactor core surveillance is most often performed using analog processing approaches and signals from neutronic sensors (fission chambers, ionization chambers, SPND, etc.) or thermal sensors (thermocouples). The processing used is often extremely simplified. A significant improvement in the performance levels of these systems can be obtained by applying digital processing to these same signals. This paper presents the TRTC Core Temperature Processing System (''TRaitement des Temperatures Coeur or TRTC'') that ensures the thermal surveillance of a fast breeder reactor core, the Superphenix unit; we also present the ALPES system that is a development of this system and which significantly improves the performance of the surveillance and protection functions. We will show that these systems can be used in all types of reactors where surveillance systems use temperature measurements that are representative of core output temperatures. (author)

[en] The methods of synthesis of Hg based superconductors are reviewed along with their various properties including structural properties under different conditions

[en] The Chilean Nuclear Energy Commission is currently performing a previous feasibility study concerning possible utilization of electron-beam process for removal of SO₂ from different types of sulfurous streams from copper smelters. First part of the project was related to verify, in a experimental line at Institute of Nuclear Chemistry and Technology, INCT, Poland, the behaviour of the process for simulated off-gases with very high SO₂ content, between 5% to 15% by volume. Tests were performed at laboratory stage and with flowrate of 5 Nm³/hr, using an ILU-6 electron accelerator, with the following results: High removal efficiencies of SO₂, up to 90% were achieved for simulated off-gases containing up to 15% of SO₂; Required dose was in the range 5 to 8 kGy; Big influence of NH₃ stoichiometry and gas humidity on SO₂ removal efficiency; Rapid generation of sub-micron solid by-product, in great amount, that causes deposits on ducts and filtration units. This work presents the experimental results and discuss is technical projections in the field of interest. (author)

[en] The removal of hydrocarbon containing compounds using a barrier discharge at atmospheric pressure (air) as well as a capacitively coupled 13.56 MHz low-pressure rf-discharge has been examined. Al plates, Si-wafer and Al coated Si-wafer served as substrate materials. In the rf-discharge, power and gas pressure were varied. Argon, oxygen, and hydrogen were used as process gases. In the barrier discharge, power variation was investigated. Spectroscopic ellipsometry was used to determine thickness and optical properties of the contamination. The removal of the contamination layers was observed by means of in-situ kinetic ellipsometry. In the rf-discharge the thickness of the lubricant decreases linearly with the treatment time. The determined removal rates per discharge power are 0.1 nm/Ws for O₂ and about 0.01 nm/Ws for Ar and H₂. In the barrier discharge the etching rate decreases about exponentially with treatment time. This is due to a beginning polymerization shown by the increase of the optical constants of the lubricant. The etching rate reaches values up to 0. 1 mm/Ws. After the removal of the lubricant the thickness of the surface oxide increases significantly. (author)

[en] The reported research was devoted to the process of thin layer deposition in a discharge at atmospheric pressure stabilized by a dielectric barrier. Thin surface layers composed mainly of silicon dioxide were produced by polycondensation of tetraethoxysilane vapor in mixtures with helium gas with a small amount of oxygen. The influence was studied of the voltage applied and of the time elapsed in the deposition process, on the thickness of the layer, as were the changes of composition of the deposited layers during and after storage. It is shown that good passivating pinhole-free silicon oxide layers can be produced in surface barrier discharges. (J.U.)

[en] An investigation of optical and electrical characteristics of a pulsed corona discharge in pure nitrogen flowing in a coaxial wire-tube electrode geometry is reported. In addition to the typical waveforms of discharge voltage and of the total discharge current, also the waveform of current in an individual streamer (recorded with a wall current probe) was observed. The average streamer propagation velocity was estimated from the measured time delay between the light signals originating near the anode and the cathode. Emission spectroscopy measurements performed in the 200 to 450 nm range revealed nitrogen and NO vibronic bands with vibrational temperatures of 2540 K and 1600 K, respectively. The rather low value of rotational temperature estimated from the band profiles (approx. 300 K) and of the average electron energy estimated from the intensity ratio of nitrogen bands (9.5 eV), correspond well with the small energy deposit in the discharge. (J.U.)

[en] The heating and loss processes in carbon rods under the influence of a microwave discharge were studied. The experimental data presented suggest that the main loss channel in the heated carbon is not electronic cooling, but heat conduction or heat convection losses. Therefore, the temperature of the carbon rod in the reported experiment is supposed to be around 300 K at maximum. For the production of C60, the temperature of the carbon rod should exceed 4000 K. Such temperatures may be achieved by increasing the repetition rate of the microwave pulses. (J.U.)

[en] This paper describes the optimizing the fuel cycle, the uranium mining industry, the uranium enrichment industry, and the reprocessing recycling industry in France. 1 tab