SBLOCA

Pressure reduction by opening of pressurizer safety valves during hot leg/cold leg SBLOCA... 

ATHLET 1.2 A system code LBLOCA,SBLOCA experimental facility... 

ATHLET 1.2A performed continuously NPP PMK- Hungary ISB Loss of flow SBLOCA... 

In addition to the above design features, guidelines are provided to assist the owner-operator in preparing emergency operating procedures detailing the actions to be taken by the plant operators in the event of a SBLOCA, as contained in report CEN-152 (Reference 4). 

Furthermore, a Tech. Spec, for verifying overfill protection availability, and emergency procedure guidelines for a SBLOCA, are established. 

Installation of Feed and Bleed at secondary side, a preventive AM, which could be applied e.g. to transients, SBLOCA, containment bypass sequences and event sequences with a complete loss of SG feedwater injection ... 

Canned motor MCPs eliminate the need for an MCP seal, and basically eliminate a potential for SBLOCA associated with seal failure. The modular type once-through SGs is located relatively high above the core to provide a driving force for natural circulation flow. This design feature along with low flow resistance enables the capability of the system to have natural circulation with the maximum power of 25%. 

Large water inventory Slow transient SBLOCA Mitigation of accident consequence... 

After the incident at the Three Mile Island nuclear plant in 1979, the nuclear industry as a whole around the world intensified experimental and analytical investigations into all aspects of namral-circulation thermal-hydraulics. The small-break loss of coolant accident (SBLOCA) natore of the incident revealed the critical importance of natural circulation to understanding the response of such systems under these conditions. The entire industry worked to ensure that understanding of all aspects SBLOCAs, for existing and future systems, was correct and complete. 

The mathematical models and numerical solution methods used in the major systems-analysis computer codes used in the industry were the subjects of research relative to applications to SBLOCA and natural circulation. During this period of intensive research, the critical importance of the discretization of the continuous equations and the associated numerical solution methods used in systems-analysis computer codes for nonlinear analyses in the time domain was one area of primary focus. 

SBLOCA Small-Break Loss of Coolant Accident... 

Aksan, N., 2008. International standard problems and small break loss-of-coolant accident (SBLOCA). Science and Technology of Nuclear Installations, http //dx.doi.org/10.1155/ 2008/814572. Article ID 814572, 22 p. 

The passive safety injection experiments in Lappeenranta started already in 1992 with a series of five experiments. These experiments simulated hot leg SBLOCA s. The PSIS included a CMT and two PBL s. The second series included four cold leg SBLOCA experiments in 1993. These experiments used similar PSIS as in the first series. In 1996, a new project of passive safety injection experiments with a CMT and one PBL started. The new experiments... 

The first experiment series included five SBLOCA tests with break in one hot leg of PACTEL. Three break sizes were used. Three tests included secondary system depressurization as an accident management measure. In all tests, only PSIS provided ECC water to the core. The primary pressure used in the tests was lower than the nominal operation pressure of PACTEL. Maximum operation pressure of the passive accumulators determined the upper limit of the experiment pressure (3.8 MPa). 

The main objective of the third series was to investigate the influences of break size and the removal of the pressurizer PBL on the CMT behaviour in cold leg SBLOCA s. The tests run with four different break sizes (from 1 to 5 mm in diameter) including reproducibility studies. Like in the earlier tests the main objective of the tests was to simulate the PSIS behaviour and not to try to simulate any proposed ALWR reactor concept in particular. 

The passive safety injection experiments in Lappeenranta started already in 1992 with a series of five experiments. These experiments simulated hot leg SBLOCA s. The PSIS included a... 

The second experiment series included four SBLOCA tests with break in one cold leg of PACTEL. Two break sizes (2 and 4 mm or 0.5 and 2%, respectively) were used. The tests also included studies of primary system depressurization and reproducibility of the phenomena (one test was repeated twice with the same initial and boundary conditions). The PACTEL operators depressurized the primary system by opening a pressurizer relief valve. The core power in the tests was 80 kW corresponding to about 1.8% of the scaled thermal power of the reference reactor. In all tests, only the CMT provided ECC water to the primary loop. 

The last series of the EC funded project included additional five SBLOCA experiments. VTT Energy and LTKK ran the experiments in August and September, 1997. Based on the experiences from the previous series, the following new experiments were performed in the third and final series of the EC funded programme ... 

The PACTEL GDE-24 experiment was calculated with APROS 4.02 code [18], [19], [20], [21]. The models of the CMT, PBL and IL were included to the APROS model of PACTEL created for SBLOCA calculations. The CMT was modelled with a standard pipe module of APROS divided in 30 equal length nodes. 

VIHAVAINEN, J., TUUNANEN, J. "Passive Safety Injection during SBLOCA from a Core Make-up Tank with a Pressure Balancing Line to Pressurizer Experiment in... 

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