The Westinghouse Nuclear Safety Advisory Letter NSAL-09-8 investigated the possibility of presence of vapor in RHR （residual heat removal） system in modes 3/4 LOCA （loss-of-coolant accident） conditions. This conce...The Westinghouse Nuclear Safety Advisory Letter NSAL-09-8 investigated the possibility of presence of vapor in RHR （residual heat removal） system in modes 3/4 LOCA （loss-of-coolant accident） conditions. This concerns the Westinghouse standard three-loops plant for which the RHR is the low pressure part of the St （safety injection）. In some cases one or both RHR trains may become inoperable for SI function. As a response to this letter, Westinghouse Electric Belgium is providing RELAP5 analyzes for Westinghouse NSSS （nuclear steam supply system） European plants to assess the thermal hydraulic behavior of the RHR suction piping system for ECCS （emergency core cooling system） initiation events postulated to occur during startup/shutdown operations. Several concerns including condensation induced water hammer and voiding at the RHR pump have been investigated. As a conclusion, the analysis allowed to define the bounding hot leg temperature conditions under which both RHR trains remain safely operable. These bounding conditions are then implemented by the customer in their OPs （operating procedures） to achieve safe operations and successful accident management.展开更多
This paper introduces the conception of seismic fragility, gives the model of seismic fragility analysis, and places emphasis on discussing quantization process of seismic fragility parameters. Then, establishes 3D mo...This paper introduces the conception of seismic fragility, gives the model of seismic fragility analysis, and places emphasis on discussing quantization process of seismic fragility parameters. Then, establishes 3D model of pipes of Chinese Experimental Fast Reactor (CEFR) accident residual heat removal system, and obtains the stresses which are essential for calculating seismic fragility parameters. Finally, combined with quantitative methods of seismic fragility, calculates the safety factors and uncertainties of CEFR pipeline, and obtains the system seismic fragility parameters: Am = 2.42 g, βr = 0.36, βu = 0.44, HCLPF = 0.65 g. The results show that: the pipeline of CEFR accident residual heat removal system has high seismic capacity.展开更多
文摘The Westinghouse Nuclear Safety Advisory Letter NSAL-09-8 investigated the possibility of presence of vapor in RHR （residual heat removal） system in modes 3/4 LOCA （loss-of-coolant accident） conditions. This concerns the Westinghouse standard three-loops plant for which the RHR is the low pressure part of the St （safety injection）. In some cases one or both RHR trains may become inoperable for SI function. As a response to this letter, Westinghouse Electric Belgium is providing RELAP5 analyzes for Westinghouse NSSS （nuclear steam supply system） European plants to assess the thermal hydraulic behavior of the RHR suction piping system for ECCS （emergency core cooling system） initiation events postulated to occur during startup/shutdown operations. Several concerns including condensation induced water hammer and voiding at the RHR pump have been investigated. As a conclusion, the analysis allowed to define the bounding hot leg temperature conditions under which both RHR trains remain safely operable. These bounding conditions are then implemented by the customer in their OPs （operating procedures） to achieve safe operations and successful accident management.
文摘This paper introduces the conception of seismic fragility, gives the model of seismic fragility analysis, and places emphasis on discussing quantization process of seismic fragility parameters. Then, establishes 3D model of pipes of Chinese Experimental Fast Reactor (CEFR) accident residual heat removal system, and obtains the stresses which are essential for calculating seismic fragility parameters. Finally, combined with quantitative methods of seismic fragility, calculates the safety factors and uncertainties of CEFR pipeline, and obtains the system seismic fragility parameters: Am = 2.42 g, βr = 0.36, βu = 0.44, HCLPF = 0.65 g. The results show that: the pipeline of CEFR accident residual heat removal system has high seismic capacity.
