Tadeja Polach - Academia.edu (original) (raw)
Papers by Tadeja Polach
Journal of Energy - Energija
The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS - Advanced PROcess S... more The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS - Advanced PROcess Simulation environment. The basis for the this model was the RELAP5/MOD3.3 Engineering Handbook, the model was updated to the 26th cycle and also includes the upflow conversion modification. A detailed model nodalisation was created for each system and every system was separately validated. The current model covers the primary circuit with the core kinetics model, the secondary circuit and their control systems. The steady state of the APROS NEK model already having been validated, the plan now is to validate the model for some transients and design basis accidents. In this article the plant behaviour after the manual reactor trip is analysed in detail. Two scenarios of the manual reactor trip transient are performed, where either the Main Steam Isolation Valve (MSIV) closes after 60s – case A, or remains open – case B. After the manual reactor trip from the 100% power, the control system...
The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS Advanced PROcess Sim... more The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS Advanced PROcess Simulation environment. The basis for this model was the RELAP5/MOD3.3 Engineering Handbook, which was updated to the 26th cycle and also includes the upflow conversion modification. A detailed model nodalisation was created for each system and every system was separately validated. The current model covers the primary circuit with the core kinetics model, the secondary circuit and their control systems. The steady state model already having been validated, the plan is to validate it for some transients and design basis accidents. In this article the plant behaviour after the Main Steam Isolation Valve (MSIV) closure is presented. The scenario of the closure of both MSIVs at the full power operation is studied. Upon initiation of the of the MSIV closure the control system signal actuations and their times were followed and the responses of different affected systems were being observed. All...
The Krško Nuclear Power Plant-NEK in Slovenia has a two loop Westinghouse PWR nuclear steam suppl... more The Krško Nuclear Power Plant-NEK in Slovenia has a two loop Westinghouse PWR nuclear steam supply system with 1994 MW thermal output power. A model of NEK is being built using the APROS-Advanced PROcess Simulation environment [1]. The aim of the work presented in this paper is to build a computer model of the core and verify and validate it. The data used to describe the properties of the system modelled in APROS, were the data describing NEK and its operational properties after the uprating and the introduction of the 18-month cycle. Basis for data collection was NEK RELAP5\MOD3.3 Engineering Handbook (23rd cycle) [2] and associated steady state report [3].
Volume 2B: Thermal Hydraulics, 2014
A model of the primary circuit and part of the secondary circuit of the Slovenian Krsko NPP – NEK... more A model of the primary circuit and part of the secondary circuit of the Slovenian Krsko NPP – NEK was built using APROS - Advanced PROcess Simulation environment. The data used to describe the properties of the system modelled in APROS, were the data describing Krsko NPP and its operational properties after the uprating and the introduction of the 18-month cycle. Basis for data collections, nodalization, structure and simplifications was NEK RELAP5\MOD3.3 Engineering Handbook and the 23rd cycle.In order to build a model describing all the important parameters, the available elements in APROS environment were used as building blocks for each system. The goal was to create a detailed model nodalization, which would give accurate results and would run on reasonable processing power. Each submodel was checked to verify that the partial results are within the allowable limits and that the description of the physical parameters is consistent with the real components. The model includes reactor pressure vessel, reactor coolant pumps and primary piping, steam generator, part of main steam, part of feedwater, pressurizer and reactor core kinetics. The regulation of pressurizer level and pressure, steam generator level and control rod is also modelled. The model consists of more than 400 thermal hydraulic volumes. The aim of building this model was a through thermal hydraulic analysis of the PWR systems present in the NPP Krsko. Several simulations of the steady states at different power levels were performed. The resulting data describing the flow rates in steam generator feedwater, reactor pressure vessel, including bypass flows, heat transfer in reactor core and steam generator, thermal losses to containment, liquid level in pressurizer and steam generator, pressure drops in primary circuit and other parameters were then compared to the results of different types of calculation and to the testing data obtained from Krsko NPP. The next step was to identify variations in results and determine whether they are consequence of wrong parameters, measurement deviation or numerical error. In that manner the model was verified and validated (in the sense of comparison with available system surveillance plant test results) to ensure the correct setup, initial and boundary conditions were applied in order to get reliable steady state results.Copyright © 2014 by ASME
Journal of Energy - Energija
The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS - Advanced PROcess S... more The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS - Advanced PROcess Simulation environment. The basis for the this model was the RELAP5/MOD3.3 Engineering Handbook, the model was updated to the 26th cycle and also includes the upflow conversion modification. A detailed model nodalisation was created for each system and every system was separately validated. The current model covers the primary circuit with the core kinetics model, the secondary circuit and their control systems. The steady state of the APROS NEK model already having been validated, the plan now is to validate the model for some transients and design basis accidents. In this article the plant behaviour after the manual reactor trip is analysed in detail. Two scenarios of the manual reactor trip transient are performed, where either the Main Steam Isolation Valve (MSIV) closes after 60s – case A, or remains open – case B. After the manual reactor trip from the 100% power, the control system...
The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS Advanced PROcess Sim... more The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS Advanced PROcess Simulation environment. The basis for this model was the RELAP5/MOD3.3 Engineering Handbook, which was updated to the 26th cycle and also includes the upflow conversion modification. A detailed model nodalisation was created for each system and every system was separately validated. The current model covers the primary circuit with the core kinetics model, the secondary circuit and their control systems. The steady state model already having been validated, the plan is to validate it for some transients and design basis accidents. In this article the plant behaviour after the Main Steam Isolation Valve (MSIV) closure is presented. The scenario of the closure of both MSIVs at the full power operation is studied. Upon initiation of the of the MSIV closure the control system signal actuations and their times were followed and the responses of different affected systems were being observed. All...
The Krško Nuclear Power Plant-NEK in Slovenia has a two loop Westinghouse PWR nuclear steam suppl... more The Krško Nuclear Power Plant-NEK in Slovenia has a two loop Westinghouse PWR nuclear steam supply system with 1994 MW thermal output power. A model of NEK is being built using the APROS-Advanced PROcess Simulation environment [1]. The aim of the work presented in this paper is to build a computer model of the core and verify and validate it. The data used to describe the properties of the system modelled in APROS, were the data describing NEK and its operational properties after the uprating and the introduction of the 18-month cycle. Basis for data collection was NEK RELAP5\MOD3.3 Engineering Handbook (23rd cycle) [2] and associated steady state report [3].
Volume 2B: Thermal Hydraulics, 2014
A model of the primary circuit and part of the secondary circuit of the Slovenian Krsko NPP – NEK... more A model of the primary circuit and part of the secondary circuit of the Slovenian Krsko NPP – NEK was built using APROS - Advanced PROcess Simulation environment. The data used to describe the properties of the system modelled in APROS, were the data describing Krsko NPP and its operational properties after the uprating and the introduction of the 18-month cycle. Basis for data collections, nodalization, structure and simplifications was NEK RELAP5\MOD3.3 Engineering Handbook and the 23rd cycle.In order to build a model describing all the important parameters, the available elements in APROS environment were used as building blocks for each system. The goal was to create a detailed model nodalization, which would give accurate results and would run on reasonable processing power. Each submodel was checked to verify that the partial results are within the allowable limits and that the description of the physical parameters is consistent with the real components. The model includes reactor pressure vessel, reactor coolant pumps and primary piping, steam generator, part of main steam, part of feedwater, pressurizer and reactor core kinetics. The regulation of pressurizer level and pressure, steam generator level and control rod is also modelled. The model consists of more than 400 thermal hydraulic volumes. The aim of building this model was a through thermal hydraulic analysis of the PWR systems present in the NPP Krsko. Several simulations of the steady states at different power levels were performed. The resulting data describing the flow rates in steam generator feedwater, reactor pressure vessel, including bypass flows, heat transfer in reactor core and steam generator, thermal losses to containment, liquid level in pressurizer and steam generator, pressure drops in primary circuit and other parameters were then compared to the results of different types of calculation and to the testing data obtained from Krsko NPP. The next step was to identify variations in results and determine whether they are consequence of wrong parameters, measurement deviation or numerical error. In that manner the model was verified and validated (in the sense of comparison with available system surveillance plant test results) to ensure the correct setup, initial and boundary conditions were applied in order to get reliable steady state results.Copyright © 2014 by ASME