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Agency: European Commission | Branch: H2020 | Program: RIA | Phase: NFRP-02-2014 | Award Amount: 4.57M | Year: 2015

When dealing with emergency, two issues with fully different time requirements and operational objectives, and thus different methods and tools, have to be considered: emergency preparedness and emergency response. This project will address both issues by combining the efforts of organizations active in these two areas to make already identified deterministic reference tools and methods a decisive step toward. In particular capabilities of these methods and tools will be extended to tackle main categories of accident scenarios in main types of operating or foreseen water-cooled NPPs in Europe, including Spent Fuel Pools. A first task will be the identification of these categories of scenario, the proposition of a methodology for their description and the development of a database of scenarios. Building this database will constitute a first important step in the harmonisation goal defended in this project. Promising probabilistic approaches based on Bayesian Belief Networks (BBN) are currently developed to complement operational deterministic methodologies and tools by contributing to diagnosis accidental situations. The development of the methodologies will be pursued in this project with the extension of the existing deterministic ones to European reactors. Both approaches will be assessed against the above mentioned database of scenarios. Finally a comprehensive set of emergency exercises will be developed and proposed to be run by a large set of partners. A first series of exercises will address source term evaluations that will be compared to the reference source terms from the scenarios database. Then a second series of exercises will be proposed on the same scenarios that will be used for the first series but accounting for the main emergency objective : to protect the populations. Progresses made by the methods and tools developed within this project will be notably assessed by comparing the results obtained in these two series of exercises.


Alpeev A.S.,Scientific and Engineering Center for Nuclear and Radiation Safety
Nuclear and Radiation Safety | Year: 2014

The paper discuses safety classification of process equipment and automation devices of nuclear power plants. It is indicated that safety classes are incorrectly transferred from safety functions to process equipment and automation devices that perform these functions. Three functional groups are proposed for equipment classification, which are the most crucial for NPP safety assurance and are the basis for developing any control system since no other control system component is characterized by such complete and unique requirements on quality indicators. A control system is just an aggregate of functional groups and their characteristics.


Lankin M.,Scientific and Engineering Center for Nuclear and Radiation Safety
11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012, PSAM11 ESREL 2012 | Year: 2012

The article sets forth algorithms, created in the process of developing Russian Risk-Informed Decision Making (RIDM) Guideline for NPPs: 1) algorithm of assessment of risk acceptability in conjunction with making a decision; 2) algorithm of assessment of decision acceptability from the point of view of its influence on the defence-indepth. he first algorithm takes into account such risk metrics as Base Severe Accident Frequency (SAF) and increase of SAF as a result of making a decision, instantaneous value of SAF, as well as Large Release Frequency (LRF) and its increase as a result of making a decision. Based on the combination of values of the abovementioned metrics and according to the developed algorithm, risk falls into one of the zones: acceptable risk (green zone), unacceptable risk (red zone) or zone of conditionally acceptable risk (yellow zone). This article describes and explains those criteria, on the basis of which borderlines between the aforementioned zones are being established. A nomenclature of threats to the defence-in-depth and of possible implementation mechanisms of the indicated threats have been proposed within the framework of the second algorithm. For the decision under analysis it is necessary to evaluate for each of the nomenclature implementation mechanisms of threats to the DiD whether the decision has influence on DiD according to the mechanism under consideration. The article presents rules of assessment of level of changes in DiD vulnerability, caused by the decision under analysis, contained in the described algorithm.


Lankin M.,Scientific and Engineering Center for Nuclear and Radiation Safety | Tokmachev G.,Atomenergo project
11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012, PSAM11 ESREL 2012 | Year: 2012

The paper considers organization, scope, issues and benefits related to interaction between industry and regulatory body in the PSA area using Russian national experience. Actually there are two main interaction points: • Regulatory reviews of safety substantiation which involves PSA or its applications; • Development of regulatory documents. Regulatory PSA review procedures are described. Interaction with industry experts in course of review process is discussed. Key issues raised during reviews and their impact on the PSA are summarized. Main PSA issues are included in the validity conditions of operational licence to be fixed within a prescribed period of time. A corpus of Russian regulatory guides in the field of PSA is described. The regulation trend in the area of PSA is discussed. PSA aspects to be additionally covered by new regulatory documents are outlined. Regulations on PSA for hazard-induced initiating events and risk informed decision making are the most recent ones. Impact and participation of the industry in development of regulatory guidelines are considered. Examples of PSA-induced proposals for changing regulatory documents (e.g., overhaul period extensions for NPPs) and associated discussion are presented. Although Fukushima like consequences are usually analysed based on deterministic stress tests initiated by the Regulatory Authority a probabilistic approach is also used for mapping this accident to Russian plants within a joint regulator-industry activity.


Lankin M.,Scientific and Engineering Center for Nuclear and Radiation Safety
11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012, PSAM11 ESREL 2012 | Year: 2012

Russian national regulatory documents require an analysis of beyond design basis accidents to be carried out for NPPs for the scope of working out control strategies for such accidents, as well as strategies of sufficiency evaluation of the NPP's technical equipment, used in mitigating the consequences of such accidents. Since sheer quantity of possible beyond design basis accidents is limitless, we face a necessity of working out selection criteria for choosing scenarios of such accidents to be taken into consideration in developing technical equipment for accident-protection, mitigation and accident control at the new NPPs, as well as in evaluation of sufficiency of such equipment at the already operational NPPs. The article presents a regulatory body's experience in developing guidelines for defining a list of beyond design basis accidents that are to be taken into account at an NPP. Developing such a list is to include examination of the following criteria: 1) representativity (from the point of view of organizing emergency response operations) of phenomenology of the processes of the scenario under analysis with reference to protection of each of the physical barriers and critical safety functions. For severe accidents, in addition to all of the above, with reference to each of the aims of accident management; 2) evaluated occurrence possibility for the scenario under analysis, taking into account uncertainty of such evaluation; 3) necessity to take into account current national and international practices of selecting scenarios of beyond design basis accidents. On their approbation the developed methods are planned to be implemented as a Regulatory Safety Guideline.


Khamaza A.,Scientific and Engineering Center for Nuclear and Radiation Safety | Lankin M.,Scientific and Engineering Center for Nuclear and Radiation Safety
PSAM 2014 - Probabilistic Safety Assessment and Management | Year: 2014

Nuclear regulatory body can exercise supervision of a considerable number of different nuclear facilities: NPPs of different capacities, generations and types, research reactors, various fuel cycle facilities, radioactive sources etc. This article presents a methodology of ranking different nuclear facilities according to the potential hazard level they represent, for the scope of optimizing controlling and supervising practices of Regulatory Body. Four criteria are proposed to be used for ranking. The first criterion is the scale of a hypothetical accident in a situation of total inefficiency of safety barriers. Depending on whether maximum hypothetical accident leads to off-site consequences and what these consequences are, as well as depending on the A/D ratio, four categories have been identified, the third of which has been further divided into four subcategories. The second and the third criteria, used for ranking, are estimated values of probabilities that operational occurrences could take place at the facility and corresponding conditional probabilities that the said occurrences would not develop into an accident of a specific level of severity. And, finally, the fourth criterion is efficiency of defence in depth of the facility. This article sets forth an algorithm of assessment of the said efficiency. It also contains a nomenclature of threats to Defence in depth and algorithm of evaluation of Defence in Depth vulnerability of the facility in respect of each of the threats and to the mechanisms of their implementation. Based on the assessment results for defence in Depth efficiency, the facility under consideration is ranked as belonging to one of the four categories. According to the rules, described in the article, after the facility under consideration has been rated according to all of the four criteria (or only according to some of them if evaluation according to the others is not possible), it is being assigned a final resulting rating of potential hazard.


Glushko A.I.,Russian Academy of Sciences | Neshcheretov I.I.,Scientific and Engineering Center for Nuclear and Radiation Safety
Quarterly Journal of Mechanics and Applied Mathematics | Year: 2012

The article deals with nonlinear elastic media deformed differently under tension and compression that can accumulate microdefects. State of the medium is assumed to be uniquely determined by strain tensor, damage tensor and temperature. The strains are assumed to be small. The damage tensor is a second-rank symmetric positive definite tensor. With the damage tensor being equal to zero, the free energy is supposed to be represented as a homogeneous function of degree 2 that is twice differentiable with respect to the strain tensor for any non-zero values of the strain tensor. We propose an approach to approximate the free energy and the rate of damage tensor that enable to obtain the well-posed mathematical model. In addition, we give the constraints on the model parameters that guarantee, under the condition that temperature is constant, the system of differential equations of the model to be hyperbolic, with any solution of that satisfying the Clausius-Duhem inequality. © 2012 The Author. Published by Oxford University Press; all rights reserved.


Borodkin P.,Scientific and Engineering Center for Nuclear and Radiation Safety | Borodkin G.,Scientific and Engineering Center for Nuclear and Radiation Safety | Khrennikov N.,Scientific and Engineering Center for Nuclear and Radiation Safety
EPJ Web of Conferences | Year: 2016

Paper describes the new approach of fitting axial fuel burn-up patterns in peripheral fuel assemblies of VVER-1000 type reactors, on the base of ex-core neutron leakage measurements, neutron-physical calculations and in-core SPND measured data. The developed approach uses results of new ex-vessel measurements on different power units through different reactor cycles and their uncertainties to clear the influence of a fitted fuel burn-up profile to the RPV neutron fluence calculations. The new methodology may be recommended to be included in the routine fluence calculations used in RPV lifetime management and may be taken into account during VVER-1000 core burn-up pattern correction. © 2016 Owned by the authors, published by EDP Sciences.


Lankin M.,Scientific and Engineering Center for Nuclear and Radiation Safety
11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012, PSAM11 ESREL 2012 | Year: 2012

Russian regulatory body, Rostechnadzor, exercises supervision of a considerable number of different nuclear facilities: NPPs of different capacities, generations and types, research reactors, various fuel cycle facilities, radioactive sources, nuclear-powered fleet etc. This article presents a developed algorithm of ranking different nuclear facilities according to the potential hazard level they represent, for the scope of optimizing controlling and supervising practices of Rostechnadzor. Four criteria are used for ranking. The first criterion is the scale of a hypothetical accident in a situation of total inefficiency of safety barriers. Depending on whether maximum hypothetical accident leads to off-site consequences and what these consequences are, as well as depending on the A/D ratio, four categories have been identified, the third of which has been further divided into four subcategories. The second and the third criteria, used for ranking, are estimated values of probabilities that operational occurrences could take place at the facility and corresponding conditional probabilities that the said occurrences would not develop into an accident of a specific level of severity. And, finally, the fourth criterion is efficiency of defence-in-depth of the facility. This article sets forth a detailed algorithm of assessment of the said efficiency. It also contains a nomenclature of threats to DiD and algorithm of evaluation of DiD vulnerability of the facility in respect of each of the threats and to the mechanisms of their implementation. Based on the assessment results for DiD efficiency, the facility under consideration is ranked as belonging to one of the four categories. According to the rules, described in the article, after the facility under consideration has been rated according to all of the four criteria (or only according to some of them if evaluation according to the others is not possible), it is being assigned a final resulting rating of potential hazard.


Lankin M.,Scientific and Engineering Center for Nuclear and Radiation Safety
International Conference on Nuclear Engineering, Proceedings, ICONE | Year: 2012

The article sets forth algorithms, created in the process of developing Russian Risk-informed Decision Making (RiDM) Guideline for Nuclear Power Plants (NPPs): 1) algorithm of assessment of risk acceptability in conjunction with making a decision; 2) algorithm of assessment of decision acceptability from the point of view of its influence on the defence-in-depth. he first algorithm takes into account such risk metrics as Base Severe Accident Frequency (SAF) and increase of SAF as a result of making a decision, instantaneous value of SAF, as well as Large Release Frequency (LRF) and its increase as a result of making a decision. Based on the combination of values of the abovementioned metrics and according to the developed algorithm, risk falls into one of the zones: acceptable risk (green zone), unacceptable risk (red zone) or zone of conditionally acceptable risk (yellow zone). This article describes and explains those criteria, on the basis of which borderlines between the aforementioned zones are being established. A nomenclature of threats to the defence-in-depth and of possible implementation mechanisms of the indicated threats have been proposed within the framework of the second algorithm. For the decision under analysis it is necessary to evaluate for each of the nomenclature implementation mechanisms of threats to the Defence-in-Depth (DiD) whether the decision has influence on DiD according to the mechanism under consideration. The article presents rules of assessment of level of changes in DiD vulnerability, caused by the decision under analysis, contained in the described algorithm. Copyright © 2012 by ASME.

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