Main Basic information of the centre Certification rus/eng
Â-213

        The BC V-213 test facility is a large-scale integrated facility modeling the vacuum pressure suppression pool of the accident localization system and the leak-tight compartments of the NPP with VVER -440/V-213 reactors. The volumetric scaling factor of the facility is 1:100. BC V-213 is designed for the conduct of thermo-hydraulic experiments to investigate operability and reliability of the vacuum pressure bubbler condenser of the NPP with VVER-440/V-213 reactors under the conditions of ultimate design basis accidents, small primary and secondary LOCA and secondary steam pipeline breaks.
        The test facility consists of the bubbler condenser (BC) model, leak-tight compartment models and water preparation module (system of pressure vessels). The BC model is a full-scale fragment of an NPP bubbler condenser, composed of 18 full-scale «tube – end cup» components in two rows, nine in a row. The elevation scale of the BC model is 1:1.
        The models of the leak-tight compartments (steam generator compartments, accident localization pit with the full-size BC fragment, air trap and dead volumes) are made to 1:100 scales. The outer walls and floor structures are rated for 0.2 MPa pressure excess.
Specially designed system of water preparatory devices, which consists of high pressure vessels and pipelines, allows modeling of the steam-water mix efflux from the primary and secondary circuit of a reactor unit during loss of coolant accidents.
        The test facility is equipped with the state of the art research automation and instrumentation and control systems. The research automation system includes more than 300 measurement channels with the sampling frequencies of 10–50 Hz. Both standard and non-standard tools are used for measurements, including pressure transmitters, temperature detectors, flow- and level meters, pressure differential, velocity, pressure oscillation detectors, instrumentation for determining air concentration in the steam-water mix, conductivity-based and ultrasonic devices for detection of the physical water level in the bubbler condenser. Video recording is used for visual monitoring of the process of water swelling in the BC plates and of the operation of cross-over and check valves. 
       In 2005, in the steam generator housing with the line of the steam-water mix discharge, a new tested core has been installed to study hydro-dynamic effect on the equipment during the break of high pressure pipelines. The high-frequency measurement system enables to determine characteristics of shock waves and coolant jets produced when breaking for different configurations of break point and equipment location.

The specifics of the design of the test facility enable it to be used for the following experimental studies
  • modeling accidents, associated with single failures of the components of the vacuum pressure suppression pool
  • assessment of leak-tightness of the containment, experimental justification of the methods for assessment of the credibility of the results of the integral containment tests
  • investigation of the structural integrity problems
  • tests of the relief valves of the steam generator compartment of a power unit with VVER-440/
    V-213 reactor;
  • modeling of BC operation in the BDBA conditions;
  • investigation of the effects of hydro-dynamical impacts upon equipment in case of pipe break accidents. 
Full-scale fragment of bubble-condenser
BC V-213

Modeling scale of volumes of the leak-tight compartments and coolant flow rates – 1:100
Number of the leak-tight compartments – 5
Number of the pressure vessels – 5
Total volume of the leak-tight compartments – 520 m3
Pressure vessel volume – 7 m3
Maximal coolant operating pressure – 12,5 MPa
Maximal coolant operating temperature – 327,5 °C
Maximal pressure in the leak-tight compartments – 0,3 MPa
   1 – air trap; 2 – WTI vessels; 3 – steam generator compartment section ¹2; 4 – bubble-condenser;
   5 – BC pit; 6 – steam generator compartment section ¹1; 7 – dead volume.

Results

       In 1999, the experimental program of the international project TACIS/PHARE No.PH2.13/95 «Bubble Condenser Experimental Qualification Project» aimed to model the operation of the vacuum pressure suppression system in case of the ultimate design basis accident (guillotine break of the cold leg of the primary circuit) at the VVER -440/213 reactor was carried out at the test facility.
       In 2002, the following experimental studies were performed at the BC V-213 test facility:

  • under an agreement with GRS (Germany), two experiments aimed at the investigation of operation of the vacuum pressure suppression system of the NPP with VVER-440/213 in the case of steam pipe break accident were performed;
  • under a contract with Paksh NPP (Hungary), three experiments modeling the operation of the vacuum pressure suppression system of NPP with VVER-440/213 in case of LOCA were performed:
    - main pipe break;
    - primary circuit leak with the equivalent diameter of 200 mm;
    - primary circuit leak with the equivalent diameter of 90 mm.

       In 2003, 6 experiments were conducted at the BC V-213 test facility in the frame of the Tacis project R2.01/99. This project was aimed at experimental qualification of the suppression pool of the accident localization system (ALS) of Kola NPP Unit 3. The test facility was preliminarily modernized in order to take into account the specifics of ALS of this unit, thereafter the 6 experiments were made, modeling the ALS behavior in case of large LOCA, small LOCA and steam pipe break. The experiment scenarios were developed based on pre-test calculations with ATHLET and COCOSYS codes. The results were applied to the NPP conditions through the computational code verification process and subsequent application of the codes for the NPP accident scenarios.
       As a result of the completed analytical and experimental studies, it was justified that the bubble-condenser ALS ensures, in hypothetical accident conditions, compliance of the design limits of pressure in the leak-tight compartments, and of pressure difference at the bubble-condenser elements for all NPPs with VVER-440 /213.
       On the figure there is shown the dependence of pressure difference (at the suppression pool) on time. This dependence was obtained in the experiment of simulation of maximum design accident (maximum design value of this parameter for NPP is 30 kPa).
       In 2005, within the framework of the contract awarded with FSUE OKB «Gidropress», two experiments on investigation of dynamic steam-water jet and shock wave effects on the equipment in the case of the pipeline break at NPP were carried out at the BC V-213 test facility. The experimental data on nonsteady-state distribution of the jet pressure of boiling coolant and shock wave at the barriers installed at different distances from the discharge nozzle were obtained as the results of the experiments. The resultant data enable to enrich substantially the results of the investigations performed by OKB «Gidropress» and Institute of Thermo-physics RAS, and to develop the program for further experimental study of the problem.