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The main criteria used in NEI 18–04 to define SSCs as risk-significant include (1) the SSC is required to keep all LBEs within the F–C target, and (2) the total frequency with the SSC failed exceeds 1% of the limit for at least one of the three cumulative risk metrics used for evaluating the integrated plant risk. The first one is a reasonable criterion in determining the risk significant SSCs. However, the second criterion may not be adequate to serve the purpose of determining the risk significance of SSCs. In the second criterion, the cumulative risk metric values representing the integrated plant risk (less the preventive and mitigative effects of the SSC being evaluated) are compared to a risk limit that represents a very small contribution to the overall integrated plant risk, which corresponds appropriately to the contributions from individual SSCs. The easiest approach to redefine the NEI 18-04 definition of risk-significant SSCs in relation to the integrated plant risk metrics is to compare the difference, between the risk metric value calculated with the SSC failed and the risk metric value calculated with the SSC credited, with 1% of the risk limit established for the integrated plant risk metrics.

The paper considers the risk management system of the operating organization in the process of maintenance and repair of nuclear power plants in Russia. The following main risks of the process are identified: an energy generation reduction due to extending outages and energy cost increase due to an increase in costs for repair and maintenance needs. The following measures for risk management of the process are considered: inspections of readiness for repair and repair quality, corporate support, development and revision of repair documentation, management of material and technical resources. The process efficiency indicators as indicators of risk tolerance are considered. An effectiveness assessment of the risk management system of the maintenance and repair process is presented. The key shortcomings are identified. The line of further research on shortcomings exclusion is formulated. [ABSTRACT FROM AUTHOR]

The main objective of the article is to present quantified and measurable risks likelihood appearance, impact and significance of inspected and monitored 48 commercial construction projects and their feasibility to be carried out. Original technical, financial and organisational feasibility studies in compliance with a rigorous Bank Investment Supervision requirements have been executed by the author in the period of 2005 – 2018. Methodology of construction project appraisal for financing and execution professional preparation have been laid out – technical documentation, arrangements, realisation. Analysis and assessment of Bank Investment Supervision consisted of project execution plan PEP, geotechnical and environmental conditions, permit design, agreements and decision impacts of local authorities, engineering contract for construction works, project insurance and performance bonds, schedule of execution tasks and their costs, payment plan, investment budget and project economical effectiveness, scope of monthly construction works execution assessed by Earned Value Method approach and handover procedure of construction project. An attempt was made to express numerically the relationship between risks impacts and their level of likelihood. Also, a method of associating the influence of projects risks impacts on the extent of the likelihood of project risk occurrence which makes possible to determine the direction and the strength of this relationship was presented. Finally, risks likelihood appearance, impact and significance variability of commercial construction projects within last two years of booming investment industry have been determined.

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