scholarly journals Experiment for Justification the Reliability of Passive Safety System in NPP

2018 ◽  
Vol 3 (3) ◽  
pp. 1
Author(s):  
D.S. Samokhin ◽  
Mohammad Alslman ◽  
A. D. Vostrilova ◽  
O.Yu. Kochnov
Keyword(s):  
Power Systems ◽  
Nuclear Power ◽  
Critical Issue ◽  
Nuclear Industry ◽  
Passive Safety ◽  
Mathematical Methods ◽  
Mean Time Between Failures ◽  
Passive Safety Systems ◽  
Passive Safety System ◽  
Safety Systems

This article gives an overview of the formation of the global nuclear industry, highlighted a critical issue of ensuring safe operation of nuclear power systems in modern projects. Considering the use of passive safety systems in the design of a nuclear power plant, and discussed the different mathematical methods for assessing the reliability of passive systems. Also it considers the possibility of finding the mean time between failures, using these methods to assess the reliability of passive safety systems.

scholarly journals Onshore Nuclear Power Plant Concept with Enhanced Passive Safety System

2019 ◽  
Vol 4 (6) ◽  
pp. 155-159
Author(s):  
A.H.M. Iftekharul Ferdous ◽  
T. H. M Sumon Rashid ◽  
Md Asaduzzaman Shobug ◽  
Tanveer Ahmed ◽  
Nitol Kumar Dutta
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Water Source ◽  
Passive Safety ◽  
Electric Power Supply ◽  
Passive Safety Systems ◽  
Passive Safety System ◽  
Safety Systems

Bangladesh is a developing country and it’s increasing economy can be maintained by providing sufficient amount of electric power supply. Therefore government is initiating Rooppur nuclear power project is one of them which is needed to be sited beside a vast amount of water source, lowest populated area and away from the locality to reduce the damage caused by any nuclear accidents. In this thesis paper we have shown that, the the dangers of residing errors of Rooppur nuclear power plant and give a proposal to go for onshore nuclear power plant in Bangladesh with two proposed designs of passive safety systems PSS-I & PSS-II. These systems will give safety to the power plants in the case of plant blackout during accidents.

scholarly journals Reliability Assessment of Passive Safety Systems for Nuclear Energy Applications: State-of-the-Art and Open Issues

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4688
Author(s):  
Francesco Di Maio ◽  
Nicola Pedroni ◽  
Barnabás Tóth ◽  
Luciano Burgazzi ◽  
Enrico Zio
Keyword(s):  
Nuclear Power ◽  
Reliability Assessment ◽  
Nuclear Industry ◽  
Passive Safety ◽  
Passive Systems ◽  
Empirical Modelling ◽  
Energy Applications ◽  
Passive Safety Systems ◽  
Safety Systems ◽  
Open Issues

Passive systems are fundamental for the safe development of Nuclear Power Plant (NPP) technology. The accurate assessment of their reliability is crucial for their use in the nuclear industry. In this paper, we present a review of the approaches and procedures for the reliability assessment of passive systems. We complete the work by discussing the pending open issues, in particular with respect to the need of novel sensitivity analysis methods, the role of empirical modelling and the integration of passive safety systems assessment in the (static/dynamic) Probabilistic Safety Assessment (PSA) framework.

Design and Non-Proliferation Viability of Small Modular Reactors

2018 ◽  
Author(s):  
Zafar ullah Koreshi
Keyword(s):  
Power Systems ◽  
Nuclear Power ◽  
Nuclear Energy ◽  
Passive Safety ◽  
Fissile Material ◽  
High Power Density ◽  
Passive Safety Systems ◽  
Small Modular Reactors ◽  
Plutonium Production ◽  
Safety Systems

Small Modular Reactors (SMRs) are economically competitive nuclear power systems aimed to provide sustainable clean safe and reliable nuclear energy free from the risk of fissile material proliferation. They are smaller versions of the present-day large nuclear power reactors with additional design simplifications, improved and reliable passive safety systems incorporating innovative concepts. With the intrinsic advantage of high power density and carbon-free emissions, SMRs and especially their innovative features are the signals for a nuclear comeback, or in Dr Alvin Weinberg’s words “the second nuclear era” in many ways. According to some estimates, there could be up to 96 SMRs by 2030. This paper addresses three vital areas to the understanding of the SMR’s in emerging global environments: (i) design, (ii) production of plutonium during operation, and (iii) their scope of applications. A representative, though very small SMR, Toshiba’s innovative 4S design is used for presenting estimates of plutonium production which are applicable to other SMRs as well. To better understand the viability of SMRs, this work considers the emerging developers, exporters and markets where SMRs can make significant improvements to the overall socio-economic development of societies challenged with formidable barriers.

Investigation of effects of nonavailability of passive safety systems on the reactor behaviour during LOCA Scenario in AP600

Kerntechnik ◽  
2021 ◽  
Vol 86 (3) ◽  
pp. 244-255
Author(s):  
S. H. Abdel-Latif ◽  
A. M. Refaey
Keyword(s):  
Passive Safety ◽  
Primary System ◽  
Water Storage Tank ◽  
The Core ◽  
Passive Safety Systems ◽  
Loss Of Coolant Accident ◽  
Passive Safety System ◽  
Stage 4 ◽  
Core Cooling ◽  
Safety Systems

Abstract The AP600 is a Westinghouse Advanced Passive PWR with a two–loop 1 940 MWt. This reactor is equipped with advanced passive safety systems which are designed to operate automatically at desired set-points. On the other hand, the failure or nonavailability to operate of any of the passive safety systems may affect reactor safety. In this study, modeling and nodalization of primary and secondary loops, and all passive reactor cooling systems are conducted and a 10-inch cold leg break LOCA is analyzed using ATHLET 3.1A Code. During loss of coolant accident in which the passive safety system failure or nonavailability are considered, four different scenarios are assumed. Scenario 1 with the availability of all passive systems, scenario 2 is failure of one of the accumulators to activate, scenario 3 is without actuation of the automatic depressurization system (ADS) stages 1–3, and scenario 4 is without actuation of ADS stage 4. Results indicated that the actuation of passive safety systems provide sufficient core cooling and thus could mitigate the accidental consequence of LOCAs. Failure of one accumulator during LOCA causes early actuation of ADS and In-Containment Refueling Water Storage Tank (IRWST). In scenario 3 where the LOCA without ADS stages 1–3 actuations, the depressurization of the primary system is relatively slow and the level of the core coolant drops much earlier than IRWST actuation. In scenario 4 where the accident without ADS stage-4 activation, results in slow depressurization and the level of the core coolant drops earlier than IRWST injection. During the accident process, the core uncovery and fuel heat up did not happen and as a result the safety of AP600 during a 10-in. cold leg MBLOCA was established. The relation between the cladding surface temperature and the primary pressure with the actuation signals of the passive safety systems are compared with that of RELAP5/Mode 3.4 code and a tolerable agreement was obtained.

Passive Safety Systems of Advanced Nuclear Power Plant: AP1000

2010 ◽  
Author(s):  
Guohua Yan ◽  
Chen Ye
Keyword(s):  
Nuclear Power ◽  
Human Error ◽  
Cooling System ◽  
Heat Removal ◽  
Injection System ◽  
Passive Safety ◽  
Human Errors ◽  
Power Sources ◽  
Passive Safety Systems ◽  
Safety Systems

In the entire history of commercial nuclear power so far, only two major accidents leading to damage of reactor core have taken place. One is Three Mile Island (TMT) accident (1979), which is caused by a series of human error, and the other is Chernobyl accident (1986), which is due to the combined reason of design defects and human errors. After TMI and Chernobyl accidents, in order to reduce manpower in operation and maintenance and influence of human errors on reactor safety, consideration is given to utilization of passive safety systems. According to the IAEA definition, passive safety systems are based on natural forces, such as convection and gravity, and stored energy, making safety functions less dependent on active systems and operators’ action. Recently, the technology of passive safety has been adopted in many reactor designs, such as AP1000, developed by Westinghouse and EP1000 developed by European vendor, and so on. AP1000 as the first so-called Generation III+ has received the final design approval from US NRC in September 2004, and now being under construction in Sanmen, China. In this paper, the major passive safety systems of AP1000, including passive safety injection system, automatic depressurization system passive residual heat removal system and passive containment cooling system, are described and their responses to a break loss-of-coolant accident (LOCA) are given. Just due to these passive systems’ adoption, the nuclear plant can be able to require no operator action and offsite or onsite AC power sources for at least 72h when one accident occurs, and the core melt and large release frequencies are significantly below the requirement of operating plants and the NRC safety goals.

Dependency Analysis of Critical Parameters Influencing the Reliability of Thermal-Hydraulic Nuclear Passive Systems

2017 ◽  
Author(s):  
Samuel Abiodun Olatubosun ◽  
Zhijian Zhang
Keyword(s):  
Nuclear Power ◽  
Critical Parameters ◽  
Passive Safety ◽  
Distribution Analysis ◽  
Passive Systems ◽  
Research Issues ◽  
Passive Safety Systems ◽  
Influencing Parameters ◽  
Safety Systems ◽  
Nuclear Applications

The deployment of passive safety systems in nuclear applications especially in advanced nuclear power reactors (both evolutionary and innovative designs) is on the rise. This can be linked to the simplicity, economic and less dependence on human interventions attributes of those passive systems. The reliability of nuclear passive systems especially the thermal-hydraulic ones is influenced by parameters which are interdependent in reality. As a result, the need to critically consider the synergetic effects of determinants of reliability of the thermal-hydraulic nuclear passive systems is of utmost importance. Reliability methodologies are now being modified by factoring the dependency nature of those determinants into reliability analysis to obtain more realistic and accurate results. This paper thus focused on the introduction of more influencing factors in parameters dependency consideration of phenomenological reliability using multivariate distribution analysis. A passively water cooled steam generator was used to demonstrate the interdependency effects of some selected critical parameters. The results obtained justified the need for considering the dependency effects of these parameters influencing the reliability of thermal-hydraulic passive systems. In addition, the research issues on dependency consideration of influencing parameters in evaluation of reliability of these nuclear passive systems were also discussed.

scholarly journals Application of REPAS Methodology to Assess the Reliability of Passive Safety Systems

2009 ◽  
Vol 2009 ◽  
pp. 1-18 ◽  
Author(s):  
Franco Pierro ◽  
Dino Araneo ◽  
Giorgio Galassi ◽  
Francesco D'Auria
Keyword(s):  
Monte Carlo ◽  
Safety Assessment ◽  
Probability Distributions ◽  
Passive Safety ◽  
Passive System ◽  
Passive Systems ◽  
Passive Safety Systems ◽  
Passive Safety System ◽  
Uncertain Input ◽  
Safety Systems

The paper deals with the presentation of the Reliability Evaluation of Passive Safety System (REPAS) methodology developed by University of Pisa. The general objective of the REPAS is to characterize in an analytical way the performance of a passive system in order to increase the confidence toward its operation and to compare the performances of active and passive systems and the performances of different passive systems. The REPAS can be used in the design of the passive safety systems to assess their goodness and to optimize their costs. It may also provide numerical values that can be used in more complex safety assessment studies and it can be seen as a support to Probabilistic Safety Analysis studies. With regard to this, some examples in the application of the methodology are reported in the paper. A best-estimate thermal-hydraulic code, RELAP5, has been used to support the analyses and to model the selected systems. Probability distributions have been assigned to the uncertain input parameters through engineering judgment. Monte Carlo method has been used to propagate uncertainties and Wilks' formula has been taken into account to select sample size. Failure criterions are defined in terms of nonfulfillment of the defined design targets.

scholarly journals Role of Passive Safety Systems in Chinese Nuclear Power Development

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
X. Cheng ◽  
Y. H. Yang ◽  
Y. Ouyang ◽  
H. X. Miao
Keyword(s):  
Nuclear Power ◽  
Passive Safety ◽  
Pressurized Water Reactors ◽  
Chinese Government ◽  
Power Development ◽  
Pressurized Water ◽  
Passive Safety Systems ◽  
Nuclear Power Development ◽  
Water Reactors ◽  
Safety Systems

Passive safety systems have been widely applied to advanced water-cooled reactors, to enhance the safety of nuclear power plants. The ambitious program of the nuclear power development in China requires reactor concepts with high safety level. For the near-term and medium-term, the Chinese government decided for advanced pressurized water reactors with an extensive usage of passive safety systems. This paper describes some important criteria and the development program of the Chinese large-scale pressurized water reactors. An overview on representative research activities and results achieved so far on passive safety systems in various institutions is presented.

AP1000™ Breaking the Dependence on Site Characteristics: Electrical Grid and Cooling Water

2009 ◽  
Author(s):  
Richard G. Anderson ◽  
Terry L. Schulz ◽  
Daniel T. McLaughlin
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Cooling Water ◽  
Passive Safety ◽  
Small Contribution ◽  
Passive Safety Systems ◽  
Design Basis ◽  
Site Characteristics ◽  
Diesel Generators ◽  
Safety Systems

The AP1000™ has been developed to use passive safety systems to address design basis and beyond design basis accidents to minimize impact on calculated plant Core Damage Frequency (CDF) and Large Release Frequency (LRF). Passive safety cases are supplemented with accident mitigation strategy using highly reliable non-safety grade systems. AP1000™ non-safety systems that resemble the safety systems of conventional plants are designed to mitigate accidents, when available. In addition, a number of mitigation schemes make use of non-safety systems together with select passive system features. This design approach has resulted in a small dependence on site characteristics and has minimized their contribution to CDF and LRF. Conventional nuclear power plants are designed to use motor driven safety grade equipment to address design basis accidents. Safety grade diesel generators are used to provide power to safety grade equipment in the event of a loss of offsite power. The contribution to CDF and LRF from Loss of Offsite Power (LOSP) or loss of cooling water events is significantly lower for the AP1000™ than that for conventional plants. The AP1000™ uses passive safety systems in conjunction with non-safety systems to reduce plant CDF and LRF sensitivity to site specific characteristics. Non-safety systems used for accident mitigation make use of high grade commercial components and are provided power from non-safety grade diesel generators upon LOSP. These components are well maintained to increase system reliability and to increase availability for accident mitigation. The effect of the non-safety systems is further enhanced by partial use of features of the passive safety systems for accident mitigation. In this way, events with initiating event frequencies often driven by site characteristics are mitigated with small contribution to CDF or LRF, often without the need to activate any, or some of the passive plant features.

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