[en] The limiting factor of the service life of the WWER reactor pressure vessel is the radiation damage to material by fast neutrons escaping from the core. Radiation damage to the material is determined by tell-tale samples placed in a test reactor on which changes in mechanical properties due to radiation are periodically ascertained. Experimental reactor LR-0 is the testing reactor simulating conditions in the WWER 440 and WWER 1000 reactor cores. The arrangement of the experiment is described as are the measuring of neutron spectra and the distribution of neutron flux density, and detectors used for the experiment. The most frequent neutron detector was a hydroaen-filled proportional counter, a stilbene monocrystal and liquid scintillators. The result of theoretical studies and highly accurate experimental measurement is the determination of the radiation load of the pressure vessel walls. (M.D.)

[en] The sensor of the in-core instrument is designed for measuring radiation in the reactor core and belongs among thermal sensors. The basic shortfall of the thermal sensors used so far is the change in their response with time caused by the burnup of the fissile nuclide in the detector material. In the sensor the detection body consists of such a mixture of fissile and non-fissile actinide isotopes that the amounts of fissile and non-fissile nuclide are in direct proportion to the ratio of effective cross sections for neutron absorption in the non-fissile nuclide to the effective cross section for the fission of the fissile nuclide. It is thus achieved that the ratio of neutron flux density and the number of fissions in the detection body remain preserved and that the sensor data are not affected by burnup during its service life. (A.K.)

[en] The SR-O research programme also includes neutron radiography. For these purposes the reactor is equipped with a cone collimator whose design allows changes to be made in the collimation ratio, i.e., the ratio of the source-to-detection-plane distance and the source size, by changing the diameter of the cadmium diaphragm in the collimator inlet window. The maximum neutron flux density at the collimator outlet is 8x10⁹ m^-2s^-1. In order to reduce the level of accompanying gamma radiation a bismuth monocrystal of a thickness of 90 mm is placed at the collimator inlet. The advantage of the collimator is the relatively large diameter of the outlet window. As an example of tests which have been made, the determination is described of the hydrogen content of WWER type fuel element cladding. The SR-O reactor is also used for the development and testing of new instrumental methods of visualization designed for mobile isotope neutron sources. (Z.M.)

No abstract available

[en] The SR-O reactor is an experimental pool-type reactor with a maximum output of 1 MW and maximum thermal neutron flux density of 5.3x10¹³ m^-2s^-1. The reactor is described in detail and its specifications are given. The protection and control systems of the reactor permit both manual and automatic operation. The reactor is used for training courses for nuclear power plant operators and for post-graduate study courses for other specialists. Intensive courses for 4 to 6 persons take 15 to 20 days. The course is adjusted to the results of introductory theoretical tests. An optimal teaching method has been developed based on the flowchart algorithmic method, dividing activities into operations (manipulations with controls, issuing commands, making records, etc.) and decision making (information reception and processing). (M.D.)

[en] Momentary corrosion rate of Zr-1%Nb alloy during nonisothermal autoclave experiments at temperature up to 328 deg. C in various solutions was determined by T/R_p values (T - absolute temperature, R_p- polarization resistance), multiplied by temperature independent conversion factor. This factor was found by comparison of conventional corrosion loss evaluation with electrochemical measurements. Corrosion rate transients in boric acid solutions and in lithium hydroxide differed significantly. Great differences were also found in stabilized corrosion rates at the end of experiments. Temperature irregularities caused considerable changes in corrosion rate. (author). 5 refs, 5 figs, 1 tab

[en] The fuel assembly (type E-1, dia 112 mm) is described for the reactor of the first Czechoslovak nuclear power station, with in-core instrumentation involving calorimeters for measuring radiation-induced heating of uranium from which may be determined the neutron flux. In addition to the theoretical background data concerning the measurement itself, the technique of processing the data obtained, as well as the results used for the thermal analysis and evaluation of the reactor's operating safety are presented. (author)

No abstract available

[en] The program of determining the radiation load of the pressure vessel wall comprises physical calculations of the reactor core, calculations of neutron transport, the development of methods of neutron spectrometry, the design and construction of mock-ups of WWER-440 and WWER-1000 reactors, measurements on these mock-ups, supplementary measurements on the SR-O reactor and measurements in nuclear power plants. The arrangement of the model experiment for WWER-440 and WWER-1000 reactors is shown by diagrams. (E.S.)

[en] The SR-O reactor is a small tank type reactor with an output of about 2000 W. It is designed for work and measurements in applied reactor physics, for the development of measuring sensors and methods, for training nuclear power plant personnel, and as a source of intensive reactor radiation. Its core is variable depending on the requirements of the experiment, the IRTM type fuel is enriched to 80% ²³⁵U. The low fuel burn-up makes possible experiments in the deep subcriticality region, which is important for the initial stage of power reactor start-up. The reactor is also used for testing control assemblies for research and experimental reactors and in the development of neutron materials testing methods. (O.K.)