Seismic Qualification (by FEA) of Emergency DG Set of Nuclear Power Plants (NPP) of NPCIL
Background:
Emergency Diesel Generator (EDG) sets are used in nuclear power plant to enable safe shut down. In emergency events, back up power is provided by emergency DG sets, and hence are very important from nuclear power plant safety. Regulatory agencies such AERB (in India) give out detailed guidelines on making the design of emergency DG sets, safe. NRC document 0420-E111 discusses the regulatory framework and regulatory framework for redundant independent emergency power systems. IAEA Safety Standards Series Safety Guide NS-G-1.6 gives an overview guideline for “Seismic Design and Qualification for Nuclear Power Plants”.
Design, Design verification, seismic evaluation as per ASME B&PV nuclear codes are mandatory for the DG sets and all auxiliaries, before they can be installed in nuclear power plants.
ProSIM (www.pro-sim.com) is an engineering consultancy company providing seismic evaluation of variety of structures, systems and components (SSCs) of NPPs. ProSIM uses its expertise in engineering, design, computer simulation (finite element analysis – FEA) for qualification of systems and optimization. ProSIM has conducted seismic evaluation of emergency DG sets for Kakrapar (KAPP) and Rawatbhata (RAPP) sites of Nuclear Power Corporation of India (NPCIL)
Figure: a finite element analysis model of the emergency DG set
ProSIM work included evaluation for safe shut down earthquake (SSE) and operational basis earthquake (OBE) of DG set and its auxiliaries such as strainers, pre-heating module, thermowells, heat exchangers, expansion tanks, HSD tanks, compressors, skid, ducting, cable trays, etc. Pipe stress analysis was performed for all associating pipelines of the auxiliaries. ProSIM has used ASME B&PV codes (Sec 3 – subsection NB, ND, NF, as needed). Entire DG set assembly – along with engine, coupling and alternator on common skid frame was qualified along with welds, anchorage/bolts.
ProSIM delivered the report of seismic evaluation using FEA, to the satisfaction of the system integrator and operator (NPCIL), in a timely manner.
For more details of ProSIM engineering, design consultancy services involving seismic design, analysis and qualification contact enquiry@pro-sim.com
