Design of all critical systems, structures, components (SSCs) and equipment of nuclear power plant (NPP) must be qualified for seismic events. Such seismic evaluation is carried out typically using ASME Boiler & Pressure vessel -B&PV-code. A globe valve design was verified by finite element analysis (FEA), seismic evaluation was done as per ASME Section III Division-1, section NC. Design was optimised to achieve qualification of valve for various load combinations including design loads, normal loads, upset loads and emergency loads. Material properties for analysis for all items of the valve assembly including body bonnet, integral seat, gland bush, plug, stem, stem nut, bellow, bellow collar, gland flange, gland nut, etc., were taken as per ASME Section-II, Part-D, Subpart-1.
A floor response spectra (FRS) for the elevation at the plant site was provided by operator (nuclear power corporation – NPCIL). Residual response is calculated accounting for the missing mass as specified by operator (NPCIL) specified document PP-P-1819-R1. Analysis was carried out for both operating basis earth quake (OBE) and safe shut down earth quake (SSE) conditions using static equivalent method. Stress linearization (SCL) was carried out as per standard procedures at ProSIM, using membrane stresses and bending stresses. Stresses calculated by finite element analysis (FEA) were compared with the allowable stresses as per ASME code, to qualify various components of the globe valve.
A design qualification document of seismic analysis was submitted by ProSIM to the nuclear power plant operator NPCIL, on behalf of the vendor of valve.
ProSIM R&D Pvt Ltd, is a Bangalore based company providing collaborative engineering and R&D services. ProSIM provides seismic evaluation of structures, systems and components (SSCs) of nuclear power plants (NPPs) of various technologies as per ASME or RCC or PNAE or similar standards. Using variety of multi-physics simulation technologies including finite element analysis, (FEA), ProSIM provides design evaluation, design optimisation, design evaluation / qualification for seismic events. For more details, contact:
Dr S Shamasundar
Managing Director, ProSIM R&D Pvt Ltd