Probabilistic seismic hazard analysis for a nuclear power plant site in southeast Brazil

Souza

Rev. IBRACON Estrut. Mater.

2021

Although Brazilian seismic activity is defined as low to moderate, it is known that intraplate earthquakes can also be associated to high intensities. In Brazil, the state of Rio Grande do Norte (RN) is one of the most seismically active areas, but there is no specific study to evaluate the seismic hazard in this region. This paper presents analyses towards improving the seismic hazard map, the peak ground acceleration value and the response spectrum of RN. The methodology is based on Probabilistic Seismic Hazard Analysis, comparing the results to the design criteria defined in the Brazilian code NBR 15421:2006 (Design of seismic resistant structures – Procedure). The analyses show that, in general, the code sets conservative values for the peak ground acceleration and for the design response spectrum; however, related to this last one, the shape is quite different.

Section: The Psha and The Acceleration Map Of The Nbr 15421 Codementioning

confidence: 99%

Section: Seismic Source Characterizationmentioning

confidence: 99%

Towards improving the seismic hazard map and the response spectrum for the state of RN/Brazil

Souza

Rev. IBRACON Estrut. Mater.

2021

“…Intensity scale (MMI)as the Brazilian territory, which is located in an intraplate area, waves reflections and refractions originated from great distances may be experienced [7].…”

Section: In Low To Moderate Seismicity Regionsclassified With Degree VI -Vii In the Modified Mercallimentioning

confidence: 99%

Overview of the seismic probabilistic safety assessment applied to a nuclear installation located in a low seismicity zone

Oliveira

Neto

et al. 2021

Braz. J. Rad. Sci.

Deterministic and probabilistic nuclear safety analysis methodologies have been developed and updated based on operational experience, investigation of past incidents or accidents, and analysis of postulated initiating events in order to maintain the protection of workers, the public and the environment. The evaluation of accident sequences and the total radiological risk resulting from off-site releases are general objectives addressed by these methodologies. There are hazards that continually challenge the safety of a nuclear facility or its nearby area. In particular, seismic events represent a major contributor to the risk of a nuclear facility. Different levels of ground motion induced by earthquakes may be experienced by the structures, systems and components (SSCs) of the installation. In this context, a seismic hazard analysis, seismic demand analysis and seismic fragility analysis must be carried out in order to characterize the local seismic hazard and what are the seismic demands on SSCs, allowing an adequate seismic classification of SSCs, even in installations located in sites with low seismicity. In this article, a general description of the Seismic Probabilistic Safety Assessment (Seismic PSA) methodology is presented, with emphasis on their support studies, aiming at applying the methodology described in this article to an experimental nuclear installation containing a PWR reactor designed for naval propulsion to be installed in a low seismicity zone in Brazil.

“…Early instrumental data in the Brazilian earthquake catalog were obtained from international agencies (USGS and ISC) and using stations from other countries. Only in the late 1960s with the installation and in the 1970s instrumental records begin in earnest [12]. Further details related to the history of the seismological stations in Brazil can be found in [13].…”

Section: Selection Of Earthquake Ground Motion Accelerogramsmentioning

confidence: 99%

Selection of earthquake ground motion accelerograms for the continental margin of Southeastern Brazil

Camelo

Tarazona

Almeida

et al. 2021

DYNA

Brazil is in an intraplate area of low to moderate seismicity, this means that few or no records of strong ground motions are available. Part of the site response analysis and seismic design of structures require the use of acceleration time-histories compatible with a specified target response spectrum. This study aims to utilize methodologies based on the use of existing earthquake records from a well-known database and synthetic accelerograms to obtain ground motions representative of the Brazilian Southeast Region, particularly in the offshore Campos Basin. Information from a probabilistic seismic hazard assessment performed in the interest area was employed as input to the methodologies applied in terms of target response spectrum and the dominant earthquake scenarios. Besides, the acceleration time-histories of two relatively recent earthquakes that occurred in the Brazilian Southeast were used to apply one of the approaches to obtain a synthetic spectrum compatible accelerogram.