The Experts below are selected from a list of 13809 Experts worldwide ranked by ideXlab platform

S. F. Erpyleva - One of the best experts on this subject based on the ideXlab platform.

  • Water chemistry of the Secondary Circuit at a nuclear power station with a VVER power reactor
    Thermal Engineering, 2017
    Co-Authors: V. F. Tyapkov, S. F. Erpyleva
    Abstract:

    Results of implementation of the Secondary Circuit organic amine water chemistry at Russian nuclear power plant (NPP) with VVER-1000 reactors are presented. The requirements for improving the reliability, safety, and efficiency of NPPs and for prolonging the service life of main equipment items necessitate the implementation of new technologies, such as new water chemistries. Data are analyzed on the chemical control of power unit coolant for quality after the changeover to operation with the feed of higher amines, such as morpholine and ethanolamine. Power units having equipment containing copper alloy components were converted from the all-volatile water chemistry to the ethanolamine or morpholine water chemistry with no increase in pH of the steam generator feedwater. This enables the iron content in the steam generator feedwater to be decreased from 6–12 to 2.0–2.5 μg/dm^3. It is demonstrated that pH of high-temperature water is among the basic factors controlling erosion and corrosion wear of the piping and the ingress of corrosion products into NPP steam generators. For NPP power units having equipment whose construction material does not include copper alloys, the water chemistries with elevated pH of the Secondary coolant are adopted. Stable dosing of correction chemicals at these power units maintains рН_25 of 9.5 to 9.7 in the steam generator feedwater with a maximum iron content of 2 μg/dm^3 in the steam generator feedwater.

R S Mishra - One of the best experts on this subject based on the ideXlab platform.

  • Methods for Improving Thermodynamic Performance of Vapour Compression Refrigeration System Using Twelve Eco Friendly Refrigerants in Primary Circuit And Nanofluid (Water- Nano Particles Based) in Secondary Circuit
    2014
    Co-Authors: R S Mishra
    Abstract:

    This paper describes thermal modeling of Vapor Compression Refrigeration System using R134a in primary Circuit and AL2O3-Water based nanofluids in Secondary Circuit. The model uses information of the Secondary fluids input conditions geometric characteristics of the system, size of nanoparticles and the compressor speed to predict the Secondary fluids output temperatures, the operating pressures, the compressor power consumption and the system overall energy performance. Such an analysis can be conveniently useful to compare the thermal performance of different nano particles(i.e Al2o3,Tio2) based nano fluid as a Secondary fluid in a Vapor Compression Refrigeration System. The influence of input variables on the output of the system is presented. Such a model can also be used to design various Components viz. Evaporator, Compressor, Condenser and Throttle Valve for Vapor Compression Refrigeration Systems for any desired cooling capacity. The use of nanofluids as a Secondary fluid in vapour compression refrigeration systems was studied and computational simulation program was developed to solve the non linear equations of the system model. Simulation results have shown that for the same geometric characteristics of the system performance increased from 17% to 20% by application of nanofluid as a Secondary fluid in VCS.

  • Performance evaluation of Vapour Compression Refrigeration system using eco friendly refrigerants in primary Circuit and nanofluid (Water- nano particles based) in Secondary Circuit
    2014
    Co-Authors: Rahul Kumar, R S Mishra
    Abstract:

    This paper describes thermal modeling of Vapor Compression Refrigeration System using R134a in primary Circuit and AL2O3-Water based nanofluids in Secondary Circuit. The model uses information of the Secondary fluids input conditions geometric characteristics of the system, size of nanoparticles and the compressor speed to predict the Secondary fluids output temperatures, the operating pressures, the compressor power consumption and the system overall energy performance. Such an analysis can be conveniently useful to compare the thermal performance of different nano particles(Cu,Al2o3,Tio2,and CuO) based nano fluid as a Secondary fluid in a Vapor Compression Refrigeration System. The influence of input variables on the output of the system is presented. Such a model can also be used to design various Components viz. Evaporator, Compressor, Condenser and Throttle Valve for Vapor Compression Refrigeration Systems for any desired cooling capacity. The use of nanofluids as a Secondary fluid in vapour compression refrigeration systems was studied and computational simulation program was developed to solve the non linear equations of the system model. Simulation results have shown that for the same geometric characteristics of the system performance increased from 17% to 20% by application of nanofluid as a Secondary fluid in VCS.

Martin Bojinov - One of the best experts on this subject based on the ideXlab platform.

  • Corrosion Behavior of Carbon Steel Coated with Octadecylamine in the Secondary Circuit of a Pressurized Water Reactor
    Journal of Materials Engineering and Performance, 2017
    Co-Authors: Essi Jäppinen, Tiina Ikäläinen, Sari Järvimäki, Timo Saario, Konsta Sipilä, Martin Bojinov
    Abstract:

    Corrosion and particle deposition in the Secondary Circuits of pressurized water reactors can be mitigated by alternative water chemistries featuring film-forming amines. In the present work, the corrosion of carbon steel in Secondary side water with or without octadecylamine (ODA) is studied by in situ electrochemical impedance spectroscopy, combined with weight loss/gain measurements, scanning electron microscopy and glow-discharge optical emission spectroscopy. The impedance spectra are interpreted using the mixed-conduction model to extract kinetic parameters of oxide growth and metal dissolution through it. From the experimental results, it can be concluded that ODA addition reduces the corrosion rate of both fresh and pre-oxidized carbon steel in Secondary Circuit significantly by slowing down both interfacial reactions and transport through the oxide layer.

V. F. Tyapkov - One of the best experts on this subject based on the ideXlab platform.

  • Water chemistry of the Secondary Circuit at a nuclear power station with a VVER power reactor
    Thermal Engineering, 2017
    Co-Authors: V. F. Tyapkov, S. F. Erpyleva
    Abstract:

    Results of implementation of the Secondary Circuit organic amine water chemistry at Russian nuclear power plant (NPP) with VVER-1000 reactors are presented. The requirements for improving the reliability, safety, and efficiency of NPPs and for prolonging the service life of main equipment items necessitate the implementation of new technologies, such as new water chemistries. Data are analyzed on the chemical control of power unit coolant for quality after the changeover to operation with the feed of higher amines, such as morpholine and ethanolamine. Power units having equipment containing copper alloy components were converted from the all-volatile water chemistry to the ethanolamine or morpholine water chemistry with no increase in pH of the steam generator feedwater. This enables the iron content in the steam generator feedwater to be decreased from 6–12 to 2.0–2.5 μg/dm^3. It is demonstrated that pH of high-temperature water is among the basic factors controlling erosion and corrosion wear of the piping and the ingress of corrosion products into NPP steam generators. For NPP power units having equipment whose construction material does not include copper alloys, the water chemistries with elevated pH of the Secondary coolant are adopted. Stable dosing of correction chemicals at these power units maintains рН_25 of 9.5 to 9.7 in the steam generator feedwater with a maximum iron content of 2 μg/dm^3 in the steam generator feedwater.

Essi Jäppinen - One of the best experts on this subject based on the ideXlab platform.

  • Corrosion Behavior of Carbon Steel Coated with Octadecylamine in the Secondary Circuit of a Pressurized Water Reactor
    Journal of Materials Engineering and Performance, 2017
    Co-Authors: Essi Jäppinen, Tiina Ikäläinen, Sari Järvimäki, Timo Saario, Konsta Sipilä, Martin Bojinov
    Abstract:

    Corrosion and particle deposition in the Secondary Circuits of pressurized water reactors can be mitigated by alternative water chemistries featuring film-forming amines. In the present work, the corrosion of carbon steel in Secondary side water with or without octadecylamine (ODA) is studied by in situ electrochemical impedance spectroscopy, combined with weight loss/gain measurements, scanning electron microscopy and glow-discharge optical emission spectroscopy. The impedance spectra are interpreted using the mixed-conduction model to extract kinetic parameters of oxide growth and metal dissolution through it. From the experimental results, it can be concluded that ODA addition reduces the corrosion rate of both fresh and pre-oxidized carbon steel in Secondary Circuit significantly by slowing down both interfacial reactions and transport through the oxide layer.