Reliability Analysis and Availability Enhancements for Redundant Systems With Reparable Components

2016 ◽  
Author(s):  
Shuqiao Zhou ◽  
Duo Li ◽  
Chao Guo
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Markov Chain Model ◽  
Life Time ◽  
Theoretical Models ◽  
Chain Model ◽  
Monitoring And Control ◽  
Monitoring Methods ◽  
Under Construction ◽  
Redundant Systems

Redundancy is widely used for enhancing a system’s overall availability. As an HTR demonstrated plant, a high temperature gas-cooled reactor pebble-bed module (HTR-PM) now is under construction in China and the construction will be completed around 2017. In HTR-PM, there are many devices and device groups used in a redundant way to guarantee the high availability of the related functions, especially the functions shared by two reactors during the entire life time. It is very important and necessary to determine their reliabilities as well as how to make a decision about the related maintenance policies to enhance their availabilities. In this paper, typical redundant styles in the HTR-PM are summarized and demonstrated. Accordingly, the theoretical models, which are able to describe the reliabilities of the redundant systems, are proposed based on Markov chain model. Moreover, for a specific redundant structure, the relationship between the availability and the maintenance period is analytically addressed. Based on the model, we address that: as the digital monitoring and control technologies are widely used in nuclear power plants, monitoring methods targeting for decreasing maintenance costs and meanwhile increasing the availabilities for different redundant styles are very beneficial.

Reliability and redundancy allocation analysis applied to a nuclear protection system

2021 ◽  
Vol 9 (2B) ◽  
Author(s):  
Alexander Lucas Busse ◽  
João Manoel Losada Moreira
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Nuclear Reactors ◽  
Block Diagram ◽  
Thermal Power ◽  
Life Time ◽  
Spare Parts ◽  
Protection System ◽  
Under Construction

Brazil is constructing with national technology two small nuclear reactors for propulsion and for radioisotope production with thermal power levels between 20 and 50 MW. These nuclear reactors fit more in the class of small modular reactors (SMR) than in the class of large nuclear power plants. In this article we apply the design approach of SMRs to propose an architecture of reactor protection systems for the small reactor under construction in the country. To do that the probabilistic analysis of the architecture of a nuclear reactor protection system is evaluated to determine the sensitivity of the components through an Reliability Block Diagram modeling. It was evaluated the modification of the architecture and the addition of redundancies when using components with lower life time than the components usually used for this purpose. The results showed that after one year of operation, the reference RPS system presents a failure probability of 0.17 %. The modified system, with components with lower life time, presents a point reliability value only 0.070 % lower than the reference one, but this difference grows exponentially over time, and in 10 years of operation it can reach values above 95%. Using equipment with lower life time characteristics implies a greater number of redundancies and, additionally, a greater number of maintenance procedures and spare parts. Therefore, this technical feasibility analysis should consider a RAM simulation as well.

Information Technology and the Development of a Global Safety Culture

2011 ◽  
pp. 558-581
Author(s):  
Susan L. Rothwell
Keyword(s):  
Information Technology ◽  
Safety Culture ◽  
Nuclear Power ◽  
Power Plants ◽  
Health And Safety ◽  
Lessons Learned ◽  
Energy Independence ◽  
Power Safety ◽  
Under Construction ◽  
Culture Development

A nuclear power plant is one of the most complex sociotechnical systems ever created, with operation requiring multiple organizations, extensive interaction, and a mission to protect public health and safety. A strong global nuclear power safety culture is important, with over 400 nuclear power plants worldwide and more under construction to reduce fossil fuel dependency. We increasingly rely on technology, stressing our need for energy independence, security, reliability, education, and safety. Lessons learned from nuclear power safety culture development have a large potential audience. Unfortunately, the complexity of nuclear power and restricted access to operational data have limited outside research on and understanding of nuclear power safety culture. This chapter provides a conceptual, methodological, empirical, and operational perspective on the development of commercial nuclear power safety culture, focusing on the role of information technology (IT) in building, maintaining, and expanding global nuclear power safety culture.

Computational Study of Conjugate Heat Transfer in T-Junctions

2009 ◽  
Author(s):  
Simon Kuhn ◽  
Bojan Nicˇeno ◽  
Horst-Michael Prasser
Keyword(s):  
Thermal Fatigue ◽  
Nuclear Power ◽  
Power Plants ◽  
Cold Water ◽  
Computational Study ◽  
Solid Wall ◽  
Turbulent Viscosity ◽  
Life Time ◽  
Scale Model ◽  
Piping Systems

Thermal fatigue is a relevant problem in the context of life-time extension of nuclear power plants (NPP). In many piping systems in NPPs hot and cold water is mixed, which leads to high temperature fluctuations in the region close to the solid wall and resulting thermal loads on the pipe walls that can cause fatigue. One of the relevant geometric test cases for thermal fatigue is the mixing in T-junctions. In this study we apply large–eddy simulations (LES) to the mixing of hot and cold water in a T-junction. We perform a set of simulations by using different formulations of the LES subgrid scale model, i.e. standard Smagorinsky and dynamic procedure, to identify the influence of the modelled subgrid scales on the simulation results. The results exhibit a large difference between the models, which is caused by the use of turbulent viscosity wall–damping functions when applying the standard model.

AFCEN RCC-F: A New Standard for the Fire Protection Design of New Built Light Water Nuclear Power Plants

2018 ◽  
Author(s):  
Bernard Gautier ◽  
Mickael Cesbron ◽  
Richard Tulinski
Keyword(s):  
Fire Protection ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Fire Hazard ◽  
Pressurized Water ◽  
Light Water ◽  
Protection Scheme ◽  
Safety Case ◽  
Under Construction

Fire hazard is an important issue for the safety of nuclear power plants: the main internal hazard in terms of frequency, and probably one the most significant with regards to the design costs. AFCEN is publishing in 2018 a new code for fire protection of new built PWR nuclear plants, so-called RCC-F. This code is an evolution of the former ETC-F code which has been applied to different EPR plants under construction (Flamanville 3 (FA3, France), Hinkley Point C (HPC, United Kingdom), Taïshan (TSN, China)). The RCC-F code presents significant enhancement and evolutions resulting from eight years of work by the AFCEN dedicated sub-committee, involving a panel of contributors from the nuclear field. It is now opened to any type of PWR (Pressurized Water Reactor) type of nuclear power plants and not any longer limited to EPR (European Pressurized Reactor) plants. It can potentially be adapted to other light water concepts. Its objective is to help engineers design the fire prevention and protection scheme, systems and equipment with regards to the safety case and the defense in depth taking into account the French and European experience in the field. It deals also with the national regulations, with two appendices dedicated to French and British regulations respectively. The presentation gives an overview of the code specifications and focuses on the significant improvements.

scholarly journals Small Modular Reactor Human-System Interface and Control Room Layout Design

2019 ◽  
Vol 63 (1) ◽  
pp. 516-520
Author(s):  
Kevin LaFerriere ◽  
Jessica Stevens ◽  
Ryan Flamand NuScale
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Monitoring And Control ◽  
Control Room ◽  
Operating Characteristics ◽  
Human System ◽  
Small Modular Reactor ◽  
Room Design ◽  
Safety Features ◽  
And Control

The NuScale Small Modular Reactor (SMR) is premised on well-established nuclear technology principles with a focus on integration of components, simplification or elimination of systems, automation, and use of passive safety features. Traditional nuclear power plants have in some cases operated up to four modules from a single control room. Due to the unique nontraditional operating characteristics of this technology a state-of-the art control room design was needed to ensure proper staffing totals for monitoring and control of multiple modules (twelve) from a single control room. To accomplish this, the human system interface and control room layout must translate the functional and task requirements needed for safe operation of the plant into the detailed design of workstations, alarms, controls, navigation, and other needs of the control room operations staff.

scholarly journals IEEE Human Factors Standards for Nuclear Facilities: The Development Process, Available Standards, Current Activities, and the Future

2019 ◽  
Vol 63 (1) ◽  
pp. 587-591
Author(s):  
David R Desaulniers ◽  
Stephen Fleger
Keyword(s):  
Human Factors ◽  
Interface Design ◽  
Nuclear Power ◽  
Power Plants ◽  
Human Performance ◽  
Development Process ◽  
Monitoring And Control ◽  
Nuclear Facilities ◽  
Computer Based ◽  
And Control

Since 1980 the Institute of Electrical and Electronics Engineers (IEEE) has supported development of human factors (HF) standards. Within IEEE, Subcommittee 5 (SC5) of the Nuclear Power Engineering Committee develops and maintains HF standards applicable to nuclear facilities. These standards are structured in a hierarchical fashion. The top-level standard (IEEE Std. 1023) defines the HF tasks required to support the integration of human performance into the design process. Five lower tier documents (IEEE Std. 845, 1082, 1289, 1786 and 1707) expand upon the upper tier standard. Presently, two new HF standards projects are underway; one to provide HF guidance for the validation of the system interface design and integrated systems operation and another for designing and developing computer-based displays for monitoring and control of nuclear facilities. SC5 is also involved in outreach activities, including sponsorship of a series of conferences on human factors and nuclear power plants.

Conceptual Design of a 4 × 300 MW Modular Nuclear Plant

2011 ◽  
Author(s):  
Asko Vuorinen
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Plant ◽  
Medium Size ◽  
Modular Construction ◽  
Construction Costs ◽  
University Of Technology ◽  
Nuclear Plants ◽  
Original Estimate ◽  
Under Construction

The Finnish companies have built four medium size nuclear power plants. In addition they have constructed two nuclear icebreakers and several floating power plants. The latest 1650 MWe nuclear power plant under construction Olkiluoto-3 has had many problems, which have raised the costs of the plant to €3500/kWe from its original estimate of €2000/kWe and constriction schedule from four to eight years. It is possible to keep the costs down and schedule short by making the plant in shipyard and transport it to site by sea. The plant could be then lifted to its place by pumping seawater into the channel. This kind of concept was developed by the author in 1991, when he was making his thesis of modular gas fired power plants in Helsinki University of Technology. The modular construction of nuclear plants has made in a form of two nuclear icebreakers, which Wa¨rtsila¨ Marine has built in Helsinki Shipyard. The latest modular nuclear plant was launched in 2010 in St Petersburg shipyard. One of the benefits of modular construction is a possibility to locate the plant under rock by making the transportation channels in tunnels. This will give the plant external protection for aircraft crash and make the outer containment unnecessary. The water channels could also be used as pressure suppression pools in case of venting steam from the containment. This could reduce the radioactive releases in case of possible reactor accidents. The two 440 MW VVER plants build in Finland had construction costs of €1600 /kWe at 2011 money. The author believes that a 1200 MW nuclear plant with four 300 MW units can be constructed in five years and with €3300/kW costs, where the first plant could be generating power within 40 months and next units with 6 month intervals.

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