ارزیابی و برنامه هوشمند از کد طراحی تجزیه و تحلیل سیستم،TASS / SMR-S برای SBLOCA
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|28107||2013||9 صفحه PDF||سفارش دهید||محاسبه نشده|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Nuclear Engineering and Design, Volume 254, January 2013, Pages 291–299
TASS/SMR-S is thermal-hydraulic design code for safety analysis of SMART plant. SBLOCA is considered as the design basis accident in the SMART. The capability of TASS/SMR-S for SBLOCA analysis was assessed using LOFT L3-7 as TMI action plan. Because TASS/SMR-S has been developed only for SMART, which is an integral reactor with helical steam generator heat exchanger, the steam generator model of TASS/SMR-S cannot be used directly for LOFT experiment that involves the use of U-tube steam generator. Therefore, the general heat structure model of TASS/SMR-S was used for modeling the SG heat exchanger. Nevertheless, TASS/SMR-S predicted important thermal-hydraulic parameters such as system pressure, fluid temperatures, and cladding temperature of reactor within reasonable error ranges. Further, TASS/SMR-S was applied to simulate SBLOCA in the SMART plant. In this simulation, thermal hydraulic parameters similar to those predicted in LOFT L3-7 were predicted.
Recently, advanced SMRs (small modular reactors) have garnered considerable attention globally. This is because SMRs have many advantages such as wide applicability; enhanced safety, owing to the adoption of inherent safety characteristics and passive features; and reasonable cost, because of simplification and modularization. An SMR has multiple purposes, such as electricity generation, water desalination, district heating, and hydrogen generation, among others. For this reason, SMRs have attracted attention in many countries that do not need a large conventional nuclear power plant owing to their population distribution, insufficient power supply networks, and limited finances. In response to the demand for SMRs, a number of these reactors have been actively developed, such as NuScale Power's NuScale; Babcock & Willcox's B&W mPower; Westinghouse's SMR; GE Hitachi's PRISM in the USA; Toshiba's 4S reactor and Mitsubishi's IMR in Japan; VBER-300, SVBR-100, and ABV6M in Russia; and KAERI's SMART in Korea. Among these SMRs, SMART (System-integrated Modular Advanced ReacTor) acquired Standard Design Approval (SDA) in July 2012. This is very meaningful to the development of SMRs worldwide, because it is the first SDA for an SMR plant (Kim et al., 2011 and Laina and Subki, 2011). SMART is one of the next-generation, integral-type SMRs developed by KAERI (Korea Atomic Energy Research Institute). The schematics of SMART are shown in Fig. 1. SMART can be used for various applications such as electricity generation, seawater desalination, and district heating. A single unit of SMART generates 330 MWth, which can provide 90 MWe of electricity and 40,000 tons of fresh water a day. Because SMART is an integral-type reactor, which houses all major components in a single vessel and eliminates the use of connecting pipes between the major components, the possibility of the occurrence of LBLOCA (large break loss of coolant accident) in SMART is eliminated (Kim et al., 2010).Further, TASS/SMR-S (transient and setpoint simulation/small and medium reactor-safety) has also been developed by KAERI; TASS/SMR-S is a thermal-hydraulic design code developed for the safety analysis of SMART. Moreover, TASS/SMR-S code uses several SMART specific models such as helical SG (steam generator) heat transfer model and PRHRS (passive residual heat removal system) model for the analysis. Furthermore, core heat transfer model, heat structure model, heat transfer model, and several critical flow models are also included in the TASS/SMR-S. The governing equations of TASS/SMR-S are homogeneous equilibrium conservation equations, which include mass, momentum, and energy equations for mixtures and a mass conservation equation for non-condensable gases. In addition, the drift-flux model can be used to simulate the two-phase flow condition that would occur during SBLOCA (small break loss of coolant accident) in SMART (Kim, 2010a). TASS/SMR-S ought to be validated using the experimental data obtained from the SET (separate effect test) and IET (integral effect test) facilities. In fact, TASS/SMR-S has already been validated on the basis of the results obtained by performing several SETs for determining the fuel heat transfer, helical SG heat transfer, PRHRS heat transfer, void distribution, critical flow, and so on (Chung et al., 2012). However, there are not many IET facilities that simulate the conditions occurring during SBLOCA. In addition, TASS/SMR-S must be assessed according to the requirements of the TMI action plan. As per this action plan, the computer codes used for the safety analysis of a reactor should be validated using the simulated-SBLOCA IET data, specifically that obtained in LOFT (loss of fluid test) (Mitsubishi, 2009) and semiscale test facilities (NRC, 1983). The L series of LOFT includes SBLOCA simulation experiments. Among these LOFT experiments, LOFT L3-7 was performed in this study to assess the safety analysis capability of TASS/SMR-S for SBLOCA in SMART. Additionally, SBLOCA scenario of SMART plant was predicted by TASS/SMR-S using same methodology.
نتیجه گیری انگلیسی
KAERI has developed the thermal-hydraulic design code TASS/SMR-S for the safety analysis of SMART. The TASS/SMR-S design code must be assessed according to the requirements of the TMI action plan for SBLOCA. As per the action plan, the computer codes used for the safety analysis of reactors should be validated using the simulated-SBLOCA IET data, specifically, that obtained in the LOFT and semiscale test facilities. Therefore, the capability of TASS/SMR-S to determine thermal-hydraulic parameters to maintain safety when SBLOCA occurs in SMART was assessed by performing the LOFT L3-7 experiment. Although TASS/SMR-S uses three homogeneous equilibrium equations for mixtures and has no specific model for a U-tube steam generator, the overall simulation results of the important thermal-hydraulic parameters such as break flow, pressure, and temperatures at important locations are found to be in good agreement with the experimental results. Thus, it is concluded that TASS/SMR-S can be applied for the safety analysis of SMART with respect to SBLOCA. Further, the SBLOCA phenomenon in the SMART plant was simulated using TASS/SMR-S. In this simulation, the lowest collapsed water level was found to be well above the active core top. In addition, as observed in the LOFT L3-7 experiment, the cladding temperature did not tend to increase rapidly.