[en] At the 'Joint Test Rig (PNS 4215) for Testing and Calibrating of Two-phase Mass Flow Measurement Techniques' roughly 250 tests were performed within the range of p = 5 - 100 bar with α = 0 - 1 und m = 0 - 4 kg/s. Velocities of 0,1 - 50 m/s for both phases and slip ratios of 1,0 - 7,0 were measured. A typical result has been represented as an example in the two diagrams. Until completion and installation in the test rig of the γ-absorption density measuring system the two-phase mass flow was calculated from the steam and water velocities measured by the radiotracer method as well as from the pressure, temperature, and superficial velocities. The values so determined showed good agreement with the balance mass flows evaluated by the IRB Institute. It was demonstrated in these two-phase velocity measurements that the gaseous and liquid tracers mix well with the related steam and liquid phase, respectively, and stay in this phase as a gas and liquid, respectively. Moreover, further knowledge was derived about the length of starting and measuring sections. Good results have been likewise obtained with the multiple beam γ-absorption density measuring system, which started operation in the fourth quarter of the year, so that it is possible now to determine the mass flow directly from the velocities of the two phase and from the density of the two-phase mixture. (orig.)

[en] The one and two phase velocity measurements performed at the water-air test section agree well with the control measurements and computations via the mass balance and have yielded the following essential results in addition: the starting sections can be reduced meanwhile to 0.1 m and the measurement sections to 0.25 m. This extends decisively the application of the method for short tubes (e.g. rupture connection of the superheated steam reactor). First two phase velocity measurements at the water-air system have been successful in the range from v = 12.5 up to 25 m/sec and with an air content of 0 to 50 vol.%. They yielded a slip factor S = 1. Selection of a specific photomultiplier and improvement of the amplifier and discriminator allow to reduce peak shifting from +- 15% to +- 3% with a variation of the counting rate from 1 to 100 kHz, which means a significant improvement of the measurement electronics. Another progress in measurement technology was achieved with the development of a new frequency voltage converter allowing to increase by a factor of four the time resolution and the sensitivity. Evaluation of tests results using the time series analyzer has already yielded good results. (orig.)

[en] The autoclave experiments carried out so far, the functional test at Battelle and the first experiments at the water-air test facility were successful. Here are the most important results: 1) The operability of the gas and liquid injection system was proved for the pressure and temperature range (p = 1 to 160 bar, t = 20 to 350⁰C) and, hence, for blowdown conditions. 2) Injection frequencies of up to 50 Hz were achieved for the two phases. 3) Although separate measurements of the velocities for the two phases, gaseous and liquid, were attained already in the first few experiments carried out at the water - air test facility, it is evident from the results that further improvements of the method, are possible by optimization of the injection and measuring techniques. (orig.)

[en] The installation of a gas velocity measurement device mounted at one of the four blowdown channels and of a two-phase velocity measurement device provided at the rupture pipe of the Marviken reactor was completed in January. The four first blowdown tests were performed from February until May. In the blowdown channels velocities from 0 to 60 m/s were measured during the four blowdowns. The maximum velocities in the individual blowdowns deviate slightly from each other. In the blowdowns 18 and 19 strong variations in velocity were found beginning some 70 seconds after the start of blowdown. In the rupture pipe the velocities ranged from 0 to 50 m/s. (orig./RW)

[en] In the blowdown channels a gas velocity of 0 to 100 m/s was measured. A comparison between the velocity of the gas phase (measured with the radiotracer measurement technique) and the liquid phase (measured with the infrared measurement technique developed in the frame of the PNS) yielded good agreement of results. This demonstrates that there was practically no slip in the blowdown channels between the gaseous and the liquid phases. First partial results are available of velocity and density measurements performed in the discharge pipe: 1. The velocity in the discharge pipe varies from 0 to 40 m/s. 2. For the void factor values from 0 to 0,5 were found. (orig./RW)

[en] The velocities measured in the blowdown channels during several blowdowns are on the order of 0 to 100 m/s. Comparison between the velocity of the gas phase, measured by the radionuclide technique, and the liquid phase, measured by infrared absorption (also developed within PNS) indicated good consistency of the measured results. This demonstrates that there was basically no slip between the gas phase and the liquid phase (smoke flow). The velocity and density measurements additionally performed at the discharge outlet proceeded successfully. It was possible to determine accurately the mass flow of the coolant at the discharge outlet. This was the first application of the radionuclide mass flow measuring technique under severe blowdown conditions. (orig./RW)