Design Of Nuclear Power Plants Research Articles

Development of new ISO 4917 standard series for the design of nuclear power plants against seismic events

Abstract The first draft of the new developed ISO standard series ISO 4917 entitled “Design of Nuclear Power Plants against Seismic Events” comprises six parts where part 1 “Principles” represents the basis for the following five parts. Part 2 concentrates on “Geotechnical Aspects”, part 3 on “Civil Structures”, part 4 on “Components”, part 5 on “Seismic Instrumentation” and part 6 on “Post Seismic Measures”. All parts have been adapted to newly developed and existing IAEA guidelines. Many restrictive clauses have been opened to accommodate major relevant national guidelines and code of practices. Several new aspects from other newly developed seismic design guidelines and recent research results have been incorporated in the new drafts. In this paper the development and the corresponding scientific background of the new ISO standard series ISO 4917 is presented.

Assessing RELAP5 performances for the simulation of Containment Wall Condenser

Abstract The new designs of Nuclear Power Plants are increasingly emphasizing the implementation of passive systems to fulfill several safety functions. Such systems operate with low driving forces, and often employ components that require a “change state” signal for actuation. These features may lead to complete or partial actuation failures, altering the driving force conditions and consequently reducing the operational ranges and reliability of the systems themselves. However, even though the operational modes differ from those of active systems, the safety standards remain equivalent. To study these possible situations, the computer system codes must be able to simulate the phenomena related to the specific system, and they should be assessed using data both from separate and integral experimental facilities. Within the framework of the EU2020 PASTELS (Passive Systems: Simulating the Thermal hydraulics with Experimental Studies) project, a series of natural circulation experiments have been conducted in the PASI facility, an open loop Containment Wall Condenser (CWC), varying initial and boundary conditions to support the validation of system codes. As project partner, ENEA developed the PASI input deck for RELAP5/mod3.3 to assess the code’s capability in simulating complex loop components, such as the sparger, and related thermohydraulic phenomena like water flashing and geysering within the open loop. This paper presents the post-test calculations conducted with RELAP5 for test 2 (quasi-static test) and test 6 (replicating the drain phase of the water storage tank).

State-of-art review of beyond design basis evaluation approach of a generic nuclear power plant in the UK

Abstract The Fukushima accident prompted rapid development in the appreciation and codification of BDB methodology into regulatory guidance and this is still continuing, especially at IAEA, which has recently and is due to publish several new standards documents directly relevant to BDB analysis. The objective of this paper is to provide a state-of-art review on how BDB evaluations are undertaken in the UK nuclear industry. Then, using the work undertaken for the Generic Design Assessment (GDA) in the UK for UK HPR1000, this paper proposed a more systematic approach for “cliff-edge” evaluation based on a generic nuclear power plant design currently being developed in the UK.

Generation of artificial earthquake time histories and power spectral density for seismic analysis of nuclear power plants

Generation of artificial earthquake time histories and power spectral density for seismic analysis of nuclear power plants

The energy output equilibrium scheme with intermediate energy storage for tokamak fusion power plant

The energy output equilibrium scheme with intermediate energy storage for tokamak fusion power plant

Validation methods in modelling the PANDA IPSS experiment: A MELCOR 2.2 assessment of a passive isolation condenser

Validation methods in modelling the PANDA IPSS experiment: A MELCOR 2.2 assessment of a passive isolation condenser

Failure criterion and seismic fragility evaluation of isolated nuclear power plant piping system using BP neural network

Failure criterion and seismic fragility evaluation of isolated nuclear power plant piping system using BP neural network

Nonlinear seismic assessment for nuclear power plants with structural-geotechnical hybrid isolation strategy

Nonlinear seismic assessment for nuclear power plants with structural-geotechnical hybrid isolation strategy

A safe reinforcement learning algorithm for supervisory control of power plants

A safe reinforcement learning algorithm for supervisory control of power plants

External Hazard Analysis for Water-Based Nuclear Power Plants

Based on recent studies, Water-Based Nuclear Power Plants (NPPs) include onshore and offshore floating NPPs, gravity-based structure NPPs, and underwater NPPs. These NPPs are increasingly considered for their benefits, such as the floating NPPs ability to distribute energy to remote areas, offshore sites, and construction activities. Regarding safety, external hazards must be considered during the design phase as stated in the Head of Nuclear Energy Regulatory Agency Regulation Number 3 Year 2011 and Specific Safety Requirements-2/1 (Rev 1). The external hazards of Water- Based NPPs should differ from those of land-based NPPs. Several studies have outlined the external hazards that water-based NPPs only address, such as onshore floating NPPs, and have yet to discuss the impact on water-based NPPs' safety. This study reviews the external hazards that must be considered and their effects on all types of Water-Based NPPs. The study is conducted by reviewing national regulations and international references to identify specific external hazards for Water-Based NPPs, followed by examining scientific works related to marine safety and Water-Based NPP design information to understand the impact of external hazards on the facilities. The review indicates that the external hazards that need to be considered for Water-Based NPPs include weather hazards, human- induced external hazards, earthquakes, and tsunamis. Keywords: NPP, Floating NPP, External Hazard, nuclear safety

CREATION AND USE OF THE LOCAL COORDINATE SYSTEM AT THE INDUSTRIAL SITE Khmelnitsky NPP

Today, nuclear power plants make up the main part of electricity production in Ukraine, providing the needs of domestic and industrial consumers, and after the full-scale invasion of the Russian Federation, systematic shelling of critical infrastructure, distribution stations and generation facilities, they became, in fact, the basis of Ukraine's energy security. Today, four nuclear power plants are in operation on the territory of Ukraine: Zaporizhzhya NPP (occupied by the Russian Federation), South Ukrainian NPP, Rivne NPP and Khmelnytsky NPP. The total capacity of operating power units on the controlled territory of Ukraine is 7,835 MW. The Chernobyl NPP is in the decommissioning stage. An important element in the design, construction and operation of nuclear power plants is to ensure the safe and reliable operation of construction structures of buildings and structures. To ensure these conditions during NPP design, design organizations develop work programs for conducting geodetic monitoring of buildings and structures both during construction and operation. In this article, we will consider the method of use GNSS measurements with its own base station and the creation of a local coordinate system to ensure the performance of geodetic monitoring of NPP buildings and structures.

Consideration of quantitative risk reduction and risk achievement measures in safe NPP design

Abstract In the models developed by probabilistic safety analyses (PSA) and in their applications associated with nuclear power plants (NPPs), the risk importance of a particular feature can be, most generally, divided into two categories: importance with respect to the risk-increase potential and importance with respect to the risk-decrease potential. A representative measure of the first category is risk achievement worth (RAW), while a representative measure of the second category is risk reduction worth (RRW). The present paper discusses the use of RAW and RRW in achieving safe design and points out some implications of their mutual dependency on the selection of a risk-reduction strategy. A simple example is provided to illustrate the differences between the two basic strategies and point out to the main issues and conclusions.

Features of the Design and Construction of Nuclear Power Plants

Features of the Design and Construction of Nuclear Power Plants

Competitiveness of companies in the design, engineering and construction of nuclear power plants

Increasing electricity consumption in the modern world makes the unique nuclear power market. It provides growing secured demand, specific external development factors. However, only four companies involved in the design, engineering, and construction of nuclear power plants (NPPs). The competitiveness of those companies included into M. Porter’s theory framework, but has its own characteristics. The purpose of the study is to determine the specifics of companies competitiveness engaged in the design, engineering, and construction of nuclear power plants, and assess the factors and prospects for their development. Besides, we define the theoretical base of international competitiveness with regard to the specific features of this economic sector, characterise the companies operating on the market, and build a model of the competitiveness formation of four representatives under the domestic factors of development. In conclusion, we will present the prospects for ROSATOM development in an internationally competitive environment. The models of competitiveness formation show the positive impact of investments in human capital, ESG agenda implementation, and long-term prospects of R&D projects. The research provides information for developing the theory of competitiveness and improving the company’s activities in this economic sector.

Simulated safety analysis of a total loss of feedwater accident in the steam generator of CPR1000 nuclear power plant

As M310 series units, CPR1000 Nuclear Power Plant in China is also the first batch of demonstration nuclear power plants in China to try out SOP(the state-oriented procedure) accident procedures. The establishment of SOP accident regulations is an important work to mitigate the consequences of radioactive accidents in the design of nuclear power plants, and it is also the embodiment of the defense-in-depth requirements in the implementation of nuclear safety regulations. It can handle superimposed accidents, human errors in program implementation and events not considered in the primary cause sequence. In order to study the efficiency of its upgraded SOP procedure and its ability to deal with severe accidents, the typical primary cause event of severe accidents in nuclear power plants–such as the total loss of feedwater accident of steam generators has been adopted for research. The initial state of the simulation is the full power operation of the nuclear power plant, the simulation process is from the loss of all the water supply accidents to the whole accident processing. A total of 30 simulation experiments were carried out. The temperature and pressure of the key parameters obtained are the average values of 30 simulation experiments. The stability and efficiency of the updated SOP are evaluated by the treatment time of the water supply loss accident and the changes of reactor temperature and pressure after the accident. The results show that the upgraded SOP procedure is more stable and efficient. The upgraded SOP procedure, when dealing with other types of accidents, has improved the treatment of residual heat conduction in the core, increased the efficiency of accident treatment, and enhanced the safety of the reactor. At the same time, based on the weaknesses of the upgraded SOP procedure, constructive suggestions on changing the setting value of the steam generator bypass valve have also been put forward accordingly. Furthermore, it can be concluded from many simulated accidents that this change will win about 5% more of the disposal time for nuclear power plants under accidents, which provides references for the subsequent upgrading of M310 series power plant procedures.

Dynamics optimization of small branch pipes in nuclear power plants based on machine learning algorithms

Dynamics optimization of small branch pipes in nuclear power plants based on machine learning algorithms

Numerical investigations of transient thermal loading of steam turbines for SMR plants

One of the well-known technologies that fit well into the goal of reduction of greenhouse gas emissions is nuclear energy. In particular, the change in approach to the design and construction of nuclear power plants led to the development of small modular reactors (SMRs), which are characterized by a broader range of possible applications than large nuclear reactors and the ability to flexibly operate as per load demand. This paper presents an analysis of the thermal loads of a steam turbine rotor operating in a power plant with SMR. Steam-water cycle and turbine train of a 300 MW unit are presented. High-pressure steam turbine rotor and its thermal loading due to varying steam conditions are investigated for a cold startup designed with consideration of the thermal characteristics of nuclear reactors. It was shown by numerical simulations that steam condensation on rotor surfaces plays a crucial role in determining its thermal behaviour. Comparison with conventional rotors has shown that the thermal loading of nuclear turbine rotors is lower and more stable than that of conventional turbines.

Convolutional neural network-based pattern recognition in natural circulation instability images

Heat removal systems employing natural circulation are key in new nuclear power plant designs for mitigating accidents. This study applies Convolutional Neural Networks (CNNs) to classify 'chugging' instability phases, analyzing 1152 two-phase flow images from a Natural Circulation Circuit. Three CNN models, including one incorporating transfer learning from the ImageNet database, were trained via five-fold cross-validation to fine-tune hyperparameters. This involved comparing models with and without transfer learning against a baseline linear model. A model using a pre-trained Resnet50 with transfer learning accurately classified all 230 samples, outperforming the baseline linear model with an F1-Score of 0.859. The results endorse the use of CNNs with transfer learning for thermohydraulic image analysis in identifying natural circulation instability stages.

The Reactor Monte Carlo code RMC: The state-of-the-art technologies, advancements, applications, and next

Based on academic research and industrial applications over more than 20 years, the Reactor Monte Carlo code (RMC) developed by the REAL (Reactor Engineering Analysis Laboratory) team at Tsinghua University since 2000 has become a powerful, innovative, and versatile simulation platform for nuclear reactor analysis, shielding simulations, criticality safety calculations, fusion neutronics analysis and beyond. Utilizing collaborative and agile development technology, advanced methods and the most cutting-edge algorithms can be tested and implemented in RMC quickly and efficiently. RMC has been deployed on many world-class supercomputers in China and played an irreplaceable role in the design and analysis of commercial nuclear power plants and newly designed types of advanced nuclear reactors. This paper reviews the state-of-the-art technologies developed in RMC in recent years, such as stochastic and continuous-varying media modeling, advanced transient simulation capability, more accurate energy deposition model, etc. Parallel acceleration on heterogeneous architecture supercomputers and machine learning algorithms would be incorporated in ongoing research and future development plans.

Dynamic soil-structure interaction analysis for base-isolated nuclear island building based on the method of external source wave motion

Dynamic soil-structure interaction analysis for base-isolated nuclear island building based on the method of external source wave motion