NPP: Power Grid Mutual Safety Assessment

NPP: Power Grid Mutual Safety Assessment

Eugene Brezhnev (Centre for Safety Infrastructure-Oriented Research and Analysis, Ukraine) and Vyacheslav Kharchenko (National Aerospace University- KhAI, Ukraine and Centre for Safety Infrastructure-Oriented Research and Analysis, Ukraine)
Copyright: © 2015 |Pages: 35
DOI: 10.4018/978-1-4666-8200-9.ch037


The problem of the safe interaction between a Nuclear Power Plant (NPP) and a Power Grid (PG), considering the Fukushima nuclear accident, is becoming topical. There are a lot different types of influences between NPPs and PG, which stipulate NPPs' safety levels. To evaluate the influences, two metrics are proposed: linguistic and numerical. The approach to the NPP-PG safety assessment is based on the application of Bayesian Belief Network (BBN), where nodes represent different PG systems and links are stipulated by different types of influences (physical, informational, geographic, etc). It is suggested to evaluate criticality of the PG system considering the change of criticalities of all connected systems. The total criticality of each node in BBN is assessed considering particular criticalities caused by different types of influence. The complex nature of NPP and PG mutual interaction calls for the need for integration of different methods that use input data of different qualimetric nature (deterministic, stochastic, linguistic). Application of one specified group of risk methods might lead to loss and/or disregard of a part of safety-related information. BBN and Fuzzy Logic (FL) represent a basis for development of the hybrid approach to capture all information required for safety assessment of NPP – PG under uncertainties. Integration of FL-based methods and BBNs allows decreasing the amount of input information (measurements) required for safety assessment, when these methods are used independently outside from the proposed integration framework. An illustrative example for the NPP reactor safety assessment is considered in this chapter.
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All facts mentioned above are given to show the high complexity of Ukrainian energy sector and problem of its reliability assurance. Reliable operation of the NPP implies that PG, to which it is connected, is reliable. Disturbances in PG operation can originate from natural disasters, failures, human factors, terrorism, and so on.

If PG and NPP are considered together as SoS, we can conclude that PG reliability and safety are stipulated by the NPP safety. Outages and faults will cause serious problems and failures in the interconnected power systems. It means that unsafe power grid and NPP could be considered mutual risk factors undermining the safety of both facilities. In order to provide stable and safe operation of NPPs, a systematic way of formalization and evaluating these influences is needed.

The object of the chapter – is to introduce approaches and techniques, which allow to evaluate the mutual influences between NPP and PG, understand the dynamic risks nature caused by their interactions.

The techniques represented in the chapter can be considered an essential part of PG risk management and can serve as a base for decision-making to avoid disturbances or minimize the severity of their consequences considering the interaction between NPP and PG systems. These techniques allow understanding the risk proliferation and develop the recommendations and measures for NPP safety assurance.

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