PROBABILISTIC RISK ASSESSMENT FOR INTEGRATING SURVIVABILITY AND SAFETY MEASURES ON NAVAL SHIPS

Conflicts of today are characterized by both traditional and irregular tactics and by non-state actors making innovative use of modern technologies. These conditions set new demands on naval ships. The aim of this investigation is to describe how, based on probabilistic risk assessment, the concept of operation for a naval ship can be turned into safety scenarios to be used in the evaluation of risk. In this investigation, civilian state-of-the-art methods for probabilistic risk assessment are merged with the specific demands of naval ships. Relevant aspects of safety culture, codes, regulations and rules are analysed with respect to requirements on safety scenarios, and military operational research with respect to modelling military systems. The results show that the scenarios must have calculable probability and must be adapted to the vessel in question. Results from simulations show that modelling operational tasks is one way to support experts in the definition of safety scenarios.

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Probabilistic Risk Assessment for Integrating Survivability and Safety Measures on Naval Ships

10.3940/rina.ijme.2012.a1.219 ◽

2012 ◽

Vol 154 (A1) ◽

Keyword(s):

Risk Assessment ◽

Safety Culture ◽

Operational Research ◽

State Of The Art ◽

Probabilistic Risk Assessment ◽

Safety Measures ◽

Military Systems ◽

Definition Of ◽

Modern Technologies ◽

Probabilistic Risk

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Bayesian inference in probabilistic risk assessment—The current state of the art

Reliability Engineering & System Safety ◽

10.1016/j.ress.2008.07.002 ◽

2009 ◽

Vol 94 (2) ◽

pp. 628-643 ◽

Cited By ~ 106

Author(s):

Dana L. Kelly ◽

Curtis L. Smith

Keyword(s):

Risk Assessment ◽

Bayesian Inference ◽

State Of The Art ◽

Probabilistic Risk Assessment ◽

Current State ◽

Probabilistic Risk

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Seismic Qualification of Equipment: A PRA-Consistent Framework

Volume 1: Operations and Maintenance, Aging Management and Plant Upgrades; Nuclear Fuel, Fuel Cycle, Reactor Physics and Transport Theory; Plant Systems, Structures, Components and Materials; I&C, Digital Controls, and Influence of Human Factors ◽

10.1115/icone24-60674 ◽

2016 ◽

Author(s):

Payel Chatterjee ◽

Abhinav Gupta

Keyword(s):

Risk Assessment ◽

Correction Factor ◽

Response Spectrum ◽

Ground Motions ◽

Spectral Response ◽

Probabilistic Risk Assessment ◽

Modal Interaction ◽

Test Response ◽

Definition Of ◽

Probabilistic Risk

The seismic probabilistic risk assessment (SPRA) for a nuclear power plant involves the estimation of fragility curves for plant equipment. The seismic qualification of an equipment based on testing requires the equipment to continue to function when subjected to a specific test response spectrum (TRS). Broad banded ground motions have been found to cause more damage to equipment than the filtered narrow banded excitations. As a result, the definition of acceleration capacity used in the fragility models use clipped response spectra for both test response spectrum (TRS) and required response spectrum (RRS). The main purpose of the clipping factors is to convert a narrow banded response spectrum to a broad banded spectrum. The broadband correction factor and the modal interaction correction factors together contribute to the definition of clipping factor. The current study involves reconciliation with previous research by generating the mean response factor for different waveforms and subsequently the root-mean-square (RMS) severity ratio as a function of bandwidth. This ratio can be estimated for real earthquakes from their peak-to-rms values and the peak spectral values. In addition it can be shown that in case of real narrow banded earthquakes, this ratio is even lower and therefore the clipping would be greater. The modal interaction correction factor which considers the effect of interaction between different modes in case of broad banded time histories has also been investigated. The primary objective of this work is to study the existing Conservative Deterministic Failure Margin (CDFM) and Probabilistic approaches for estimating these factors as per the guidelines of EPRI [2] and apply the same to real life ground motions. It has been observed that the recommended practices are based on studying the behavior of random ground motions generated artificially for different bandwidths and center frequencies. The present study aims towards a more realistic fragility estimation of equipment by studying the spectral response of equipment based on actual ground motions. The purpose is to evaluate clipping factors that are consistent with Seismic Probabilistic Risk Assessment.

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