Seismic Risk Mitigation and the Futrure of the Nuclear Power Programme in Nigeria

Abstract

Seismic Risk Mitigation and the future of the Nuclear Power Program in Nigeria The seminar is a concise attempt to emphasize the possibility of seismic fault activities in Nigeria in the face of favorable geography while attempting an overview of how seismic risk mitigation is central to the safety of the proposed Nuclear Power Program (NPP). It also highlights the urgent need for the NNRA to incorporate seismic isolation system or technology as part of the terms and conditions of power reactor operation license as well as underscoring the need for developing seismic design basis for critical infrastructures throughout the federation. Bilham, 1998 is quoted to have said that “Earthquakes don’t kill people…buildings do. Earthquake resistant construction costs only 10% more than nonresistant construction”. In Nigeria, previous seismic studies have shown that the geographical location of the country does not fall within the earthquake prone zones or that of any other natural hazards, but recently there has been renewed cause for alarm following various recorded earth tremors which has reawakened the debate about a possible earthquake within the Nigerian enclave, especially along the areas of Zungeru, Ijebu-Ode, Kanganye, and Abeokuta where in the past, either earthquakes or tremors occurred. Also, remote sensing in addition to geological and geophysical studies reveals the presence of a deep seated pre-Cambrian NNE-SSW lineament (Ifewara-Zungeru fault zone) which transcends the western half of the country and has been shown to have links with some fracture zones in the Atlantic fracture system. The dynamics of the Atlantic fracture zones have been suggested to be responsible for the seismic activities experienced in these areas. A cursory look at the history of earthquakes in Nigeria reveals that within a timeline of 76 years, from 1933 to 2009 that eleven earthquakes/earth tremors have occurred mostly within the Ibadan axis. Base isolation which is also known as seismic or base isolation system, is a collection of structural elements which should substantially decouple a superstructure from its substructure resting on a shaking ground thus protecting the structural integrity of a building or non-building structure. Base isolation or seismic isolation system (SIS) has been reckoned as the most powerful tool of earthquake engineering pertaining to the passive structural vibration control technologies. It is designed as a measure to protect a building or non-building structure from a potentially devastating seismic impact through a proper initial design or subsequent modifications. In most cases, application of base isolation can raise both a structure's seismic performance and its seismic sustainability considerably. Almost eighty structures around the world, most especially buildings, nuclear power plants and bridges have incorporated seismic isolation system within its structure. Going by way of recommendation to minimize possible risks, it would be prudent to train officers in the field of seismology while encouraging them to seek training at the ICTP.S. In addition, adequate study of the Crustal and Mantle structure beneath South western Nigeria should be carried out by Nigerian Geoscientists through the Nigerian Geological Survey Agency (NGSA) and Nigeria should commence the monitoring and prediction of earthquake hazards by proper documentation of the pathways through which they emanate, using seismological data. Seminar presented by, Godwin Omeje