Laser surface melting of nickel-based alloy reduces nickel release in the primary cooling system of a nuclear power plant

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

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Application of TRACE and FRAPTRAN in the Spent Fuel Pool of Chinshan Nuclear Power Plant

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.479-480.543 ◽

2013 ◽

Vol 479-480 ◽

pp. 543-547

Author(s):

Jong Rong Wang ◽

Hao Tzu Lin ◽

Wan Yun Li ◽

Shao Wen Chen ◽

Chun Kuan Shih

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Nuclear Power ◽

Cooling System ◽

Safety Issue ◽

Water Injection ◽

Safety Analysis ◽

Spent Fuel ◽

Spent Fuel Pool ◽

Study Case

In the nuclear power plant (NPP) safety, the safety analysis of the NPP is very important work. In Fukushima NPP event, due to the earthquake and tsunami, the cooling system of the spent fuel pool failed and the safety issue of the spent fuel pool generated. In this study, the safety analysis of the Chinshan NPP spent fuel pool was performed by using TRACE and FRAPTRAN, which also assumed the cooling system of the spent fuel pool failed. There are two cases considered in this study. Case 1 is the no fire water injection in the spent fuel pool. Case 2 is the fire water injection while the water level of the spent fuel pool uncover the length of fuel rods over 1/3 full length. The analysis results of the case 1 show that the failure of cladding occurs in about 3.6 day. However, the results of case 2 indicate that the integrity of cladding is kept after the fire water injection.

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Bratislavia dadayi (Michaelsen 1905) (Annelida, Clitellata, Naididae): discovery of an alien oligochaete in a technogenic fresh water body in Ukraine

Zootaxa ◽

10.11646/zootaxa.4711.2.7 ◽

2019 ◽

Vol 4711 (2) ◽

pp. 349-365

Author(s):

VLADIMIR A. GUSAKOV ◽

ANZHELIKA A. SYLAIEVA

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Fresh Water ◽

Water Body ◽

Nuclear Power ◽

Potential Distribution ◽

Cooling System ◽

European Continent ◽

Previous Record ◽

Sexually Mature

A non-native oligochaete, Bratislavia dadayi (Michaelsen 1905), is recorded from a water body of the cooling system of the Khmelnitsky Nuclear Power Plant (Ukraine). This is the first registration of this species in the central part of the European continent, far from sea and river navigable waterways. The only previous record of B. dadayi in Europe had been from a Belgian estuary. The occurrence in samples taken over several years, and the presence of sexually mature individuals in the Ukrainian population indicate the worm’s successful naturalization in the new habitat. In this paper, we analyze the species’ morphology and abundance in the Ukrainian population and discuss its ecology, current and potential distribution.

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Dynamic Buckling of Axisymmetric Shells

Journal of Applied Mechanics ◽

10.1115/1.3423434 ◽

1974 ◽

Vol 41 (4) ◽

pp. 1063-1068 ◽

Cited By ~ 5

Author(s):

A. Kalnins

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Free Vibration ◽

Dynamic Stability ◽

Nuclear Power ◽

Cooling System ◽

Dynamic Buckling ◽

Reference Surface ◽

Long Duration ◽

Axisymmetric Shells

A procedure for the analysis of dynamic buckling of axisymmetric shells subjected to axisymmetric, periodic loads of long duration is proposed that is based on the calculation of the nonsymmetric modes of free vibration and associated mode integrals over the reference surface of the shell. Numerical results are presented for the evaluation of dynamic stability of an actual shell that is designed for the cooling system of a nuclear power plant.

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Invariant methods for an ensemble-based sensitivity analysis of a passive containment cooling system of an AP1000 nuclear power plant

Reliability Engineering & System Safety ◽

10.1016/j.ress.2015.10.006 ◽

2016 ◽

Vol 151 ◽

pp. 12-19 ◽

Cited By ~ 4

Author(s):

Francesco Di Maio ◽

Giancarlo Nicola ◽

Emanuele Borgonovo ◽

Enrico Zio

Keyword(s):

Sensitivity Analysis ◽

Power Plant ◽

Nuclear Power Plant ◽

Nuclear Power ◽

Cooling System

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Research on Operating Strategy of Total Loss of Essential Service Water System With RHR Not Connected in PWR Unit

Volume 2: Nuclear Policy; Nuclear Safety, Security, and Cyber Security; Operating Plant Experience; Probabilistic Risk Assessments; SMR and Advanced Reactors ◽

10.1115/icone2020-16145 ◽

2020 ◽

Author(s):

Shengtao Zhang ◽

Ke Yi

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Heat Sink ◽

Nuclear Power ◽

Cooling System ◽

Water System ◽

Total Loss ◽

Operating Strategy ◽

Service Water ◽

Essential Service

Abstract Essential Service Water System (WES) is part of the nuclear power plant cooling system which provides the final heat sink for nuclear power plants. Therefore, WES must operate stably, safely and reliably for a long time. The total loss of WES accident is a design extended condition and will result in the loss of the final heat sink of the unit. The consequences of the accident are severe. In order to deal with the accident quickly and effectively and ensure the safety and economics of the power plant in accident condition, it’s necessary to formulate corresponding treatment strategy to deal with the transient. This paper developed a strategy for dealing with the total loss of WES with Residual Heat Removal System (RHR) not connected condition in Generation III nuclear power plant. The structure of the WES system and the types of failures that may occur are analyzed, and thus the symptoms of the faults are obtained and the entry conditions for the operating strategy are determined. The effect of faults on unit equipment and safety functions and the impact on nuclear steam supply system (NSSS) control are analyzed in this paper. Combined with the unit design, the system and equipment for controlling and mitigating related safety functions are analyzed, and the mitigation method and the fallback strategy of the fault are determined. Thereby a complete operating strategy of total loss of WES with RHR not connected is obtained. In addition, this paper analyzes and evaluates the operating strategy by simulating thermal hydraulic calculation for the first time. The results show that without staff intervention Component Cooling System (WCC) temperature reached 55°C limits after running a few minutes. Based on the intervention of the operating strategy proposed in this paper, WCC temperature reached the 55°C limits when the unit was operated at about 4 hours and 55 minutes. The result shows that and the strategy can effectively alleviate the failure and provide sufficient intervention time for the operator to bring the unit to a safe state.

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Hybrid heat pipe based passive in-core cooling system for advanced nuclear power plant

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2015.07.045 ◽

2015 ◽

Vol 90 ◽

pp. 609-618 ◽

Cited By ~ 19

Author(s):

Yeong Shin Jeong ◽

Kyung Mo Kim ◽

In Guk Kim ◽

In Cheol Bang

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Heat Pipe ◽

Nuclear Power ◽

Cooling System ◽

Core Cooling

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Accident Analysis of Fukushima Daiichi Nuclear Power Plant Unit 2 by the SAMPSON Severe Accident Code

Volume 2B: Thermal Hydraulics ◽

10.1115/icone22-30670 ◽

2014 ◽

Cited By ~ 1

Author(s):

Atsuo Takahashi ◽

Marco Pellegrini ◽

Hideo Mizouchi ◽

Hiroaki Suzuki ◽

Masanori Naitoh

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Nuclear Power ◽

Cooling System ◽

Severe Accident ◽

Accident Analysis ◽

Unknown Boundary ◽

Long Time ◽

Fukushima Daiichi ◽

Nuclear Power Plant Unit

The transient process of the accident at the Fukushima Daiichi Nuclear Power Plant Unit 2 was analyzed by the severe accident analysis code, SAMPSON. One of the characteristic phenomena in Unit 2 is that the reactor core isolation cooling system (RCIC) worked for an unexpectedly long time (about 70 h) without batteries and consequently core damage was delayed when compared to Units 1 and 3. The mechanism of how the RCIC worked such a long time is thought to be due to balance between injected water from the RCIC pump and the supplied mixture of steam and water sent to the RCIC turbine. To confirm the RCIC working conditions and reproduce the measured plant properties, such as pressure and water level in the pressure vessel, we introduced a two-phase turbine driven pump model into SAMPSON. In the model, mass flow rate of water injected by the RCIC was calculated through turbine efficiency degradation the originated from the mixture of steam and water flowing to the RCIC turbine. To reproduce the drywell pressure, we assumed that the torus room was flooded by the tsunami and heat was removed from the suppression chamber to the sea water. Although uncertainties, mainly regarding behavior of debris, still remain because of unknown boundary conditions, such as alternative water injection by fire trucks, simulation results by SAMPSON agreed well with the measured values for several days after the scram.

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G124 Possibility of Cooling System for Nuclear Power Plant without Power Supply

The Proceedings of the Thermal Engineering Conference ◽

10.1299/jsmeted.2011.167 ◽

2011 ◽

Vol 2011 (0) ◽

pp. 167-168

Author(s):

Shigenao Maruyama

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Power Supply ◽

Nuclear Power ◽

Cooling System

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Reliability of PCCS in AP1000 Based on Accident Development

Volume 4: Computational Fluid Dynamics (CFD) and Coupled Codes; Decontamination and Decommissioning, Radiation Protection, Shielding, and Waste Management; Workforce Development, Nuclear Education and Public Acceptance; Mitigation Strategies for Beyond Design Basis Events; Risk Management ◽

10.1115/icone24-60155 ◽

2016 ◽

Author(s):

Yu Yu ◽

Shengfei Wang ◽

Fenglei Niu

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Physical Process ◽

System Reliability ◽

Nuclear Power ◽

Cooling System ◽

Natural Circulation ◽

System Structure ◽

System Failure ◽

Process Failure

Passive containment cooling system (PCCS) is an important safety-related system in AP1000 nuclear power plant, by which heat produced in reactor is transferred to the heat sink – atmosphere – based on natural circulation, independent of human response or the operation of outside equipments, so the reactor capacity of resisting external hazards (earthquake, flood, etc.) is improved. However since the system operation based on natural circulation, many uncertainty factors such as temperatures of cold and heat sources will affect the system reliability, and physical process failure becomes one of the important contributors to system failure, which is not considered in the active system reliability analysis. That is, the system will lose its function since the natural circulation cannot be established or kept even when the equipments in the system can work well. The function of PCCS in AP1000 is to transfer the heat produced in the containment to the environment and to keep the pressure in the containment below its threshold. After accidents the steam is injected to the containment and can be cooled and condensed when it arrives at the containment wall, then the heat is transferred to the atmosphere through the steel vessel. So the peak value of the pressure is influenced by the steam situation which is injected into the containment and the heat transfer and condensate processes under the accidents. In this paper the dynamic thermal-hydraulic (T-H) model simulating the fluid performance in the containment is established, based on which the system reliability model is built. Here the total pressure in the containment is used as the success criteria. Apparently the system physical process failure may be related to the system working state, the outside conditions, the system structure parameters and so on, and it’s a heavy work to analyze the influences of all the factors, so only the effects of important ones are included in the model. Monte Carlo (MC) simulation is used to evaluate the system reliability, in which the input parameters such as air temperature are sampled based on their probabilistic density distributions. The pressure curves along with the accident development are gained and the system reliabilities under different accidents are gotten as well as the main contributors. The results illustrate that the system physical process failure probabilities are varied under different climate conditions, which result in the system reliability and the main contributors to system failure changing, so the different methods can be taken to improve the system reliability according to the local condition of the nuclear power plant.

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