Houston, TX, United States
Houston, TX, United States

Integrated Electrical Services, Inc. is a national provider of electrical and communications "solutions" headquartered in Houston, Texas. The company offers "solutions" and project delivery of electrical and low-voltage services—including communications, network and security "solutions".Integrated Electrical Services has 114 locations with 7,000 employees across the continental United States of America and was formerly a Fortune 1000 company. Wikipedia.


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Liao J.,Integrated Electrical Services | Cao L.,Integrated Electrical Services | Ohkawa K.,Integrated Electrical Services | Frepoli C.,Integrated Electrical Services
International Congress on Advances in Nuclear Power Plants 2012, ICAPP 2012 | Year: 2012

The non-condensable gases condensation suppression model is important for a realistic LOCA safety analysis code. A condensation suppression model for direct contact condensation was previously developed by Westinghouse using first principles. The model is believed to be an accurate description of the direct contact condensation process in the presence of non-condensable gases. The Westinghouse condensation suppression model is further revised by applying a more physical model. The revised condensation suppression model is thus implemented into the WCOBRA/TRAC-TF2 LOCA safety evaluation code for both 3-D module (COBRA-TF) and 1-D module (TRAC-PF1). Parametric study using the revised Westinghouse condensation suppression model is conducted. Additionally, the performance of non-condensable gases condensation suppression model is examined in the ACHILLES (ISP-25) separate effects test and LOFT L2-5 (ISP-13) integral effects test.


Liao J.,Integrated Electrical Services
Annals of Nuclear Energy | Year: 2016

The development of the FULL SPECTRUM™ LOCA (FSLOCA™) evaluation model followed the Evaluation Model Development and Assessment Process (EMDAP). The EMDAP emphasizes the scaling analysis of the system code, the closure models, and the integral effects tests (IETs) and the separate effects tests. For the system level scaling perspective, the top-down scaling approach evaluates the global system behaviors and the system interactions from IETs, and addresses the similarity between the IETs and the prototype of PWR. In the FSLOCA evaluation model, the ROSA-IV/LSTF IET facility is selected as the key facility in the validation matrix of the WCOBRA/TRAC-TF2 system code, because it is the largest scaled (1/48 power to volume) and full height SBLOCA IET facility to a PWR. In this work, the system level scaling distortion between the ROSA-IV/LSTF integral effects test facility and a Westinghouse three-loop PWR is investigated. The top-down scaling in the blowdown, natural circulation, loop seal clearance, and boil-off phases in the ROSA-IV/LSTF SB-CL-02 test was investigated relative to the three-loop PWR SBLOCA transient. The top-down scaling analysis results indicated that there are small distortions originating from the atypical steady state and transient in the ROSA-IV/LSTF test. In general, the system scaling analysis demonstrated that the ROSA-IV/LSTF tests are well scaled IETs for examining the behavior of Westinghouse three-loop PWRs under the SBLOCA transient conditions, and are uniquely suited in the SBLOCA validation matrix of the FSLOCA evaluation model. © 2015 Elsevier Ltd.


Liao J.,Integrated Electrical Services | Ohkawa K.,Integrated Electrical Services
International Topical Meeting on Nuclear Reactor Thermal Hydraulics 2015, NURETH 2015 | Year: 2015

The FULL SPECTRUMTM LOCA (FSLOCATM) evaluation model, which utilized WCOBRA/TRAC-TF2 system code, is the latest Westinghouse LOCA evaluation model for analyzing both large break LOCA and small break LOCA in PWR. The ROSA-IV integral effects test (IF.T) facility is the key facility in validation matrix of the WCOBRA/TRAC-TF2 code. The ROSA-IV facility is a 1/48 power/volume scaled ILT facility to a four loop Westinghouse PWR, and the scaling factor and scaling distortion have been extensively studied. However, the pilot PWR in Full Spectrum LOCA evaluation model is a three-loop Westinghouse PWR, which leads to different scaling factor and distortions. Top-down scaling approach evaluates the global system behaviors and system interactions from IETs, and addresses the similarity between the IETs and the prototype PWR. The top-down scaling has been used to investigate scale distortion between the AP600 PWR and the APEX integral effects test facility and between US-APWR and the ROSA-IV integral effects test facility. In this work, the scaling distortion between the ROSA-IV integral effects test facility and a Westinghouse three-loop PWR is investigated using the top-down scaling analysis. The top-down scaling in the blowdown, natural circulation, loop seal clearing, and boil off phases in a ROSA-IV SB-CL-02 test was investigated relative to the three-loop PWR SBLOCA transient. The top-down scaling analysis results indicated that there are minor scale distortions originating from the atypical steady state and transient initiation of ROSA-IV test. The scale analysis demonstrated that the ROSA-IV tests are well scaled IETs for examining the behavior of Westinghouse three-loop PWRs under the SBLOCA transient conditions, and are uniquely suited for the validation of WCOBRA.TRAC-TF2 for the application to SBLOCA analysis.


Liao J.,Integrated Electrical Services | Frepoli C.,Integrated Electrical Services | Frepoli C.,FPoliSolutions LLC | Ohkawa K.,Integrated Electrical Services
Nuclear Engineering and Design | Year: 2015

Direct contact condensation in the cold leg of pressurized water reactor is an important phenomenon during a postulated loss-of-coolant accident. The amount of condensation in the cold legs impacts the thermal hydraulic behavior of the reactor coolant system and eventually the integration of reactor nuclear core. A cold leg condensation model was developed for the WCOBRA/TRAC-TF2 safety analysis code. The model correlated the COSI test data and addressed the scaling issues with respect to geometry, pressure, and steam and water flow rates expected during a typical PWR LOCA. The correlation was found to be in good agreement with separate effects and integral effects experimental data and implemented in the WCOBRA/TRAC-TF2 safety analysis code. The cold leg condensation model was assessed against various small break and large break LOCA separate effects tests such as COSI experiments, ROSA experiments and UPTF experiments. Those experiments cover a wide range of cold leg dimensions, system pressures, mass flow rates, and fluid properties. All the predicted condensation results match reasonably well with the experimental data. Scalability discussions on the diameter, flow area, length, superficial velocity, Reynolds number of both cold leg and SI line, and Froude number of SI line in the Westinghouse COSI test facility were provided. The distortion of the SI jet Reynolds number is moderate. The scaling analysis together with the validation matrix covering a wide range of cold leg diameter, SI flow rate and SI Reynolds number support the scalability of the developed cold leg condensation model to the full scale PWR application. © 2015 Elsevier B.V. All rights reserved.


Liao J.,Integrated Electrical Services | Ohkawa K.,Integrated Electrical Services | Frepoli C.,Integrated Electrical Services | Frepoli C.,FPoliSolutions LLC
Nuclear Engineering and Design | Year: 2015

For the two-phase flow in a horizontal pipe, individual phases may separate because of gravity. This horizontal stratification significantly impacts interfacial drag, interfacial heat transfer and wall drag of the two-phase flow. Due to the low interfacial drag and the low interfacial heat transfer, the horizontal stratification in reactor coolant systems is a highly important phenomenon during a postulated loss-of-coolant accident in PWR. The horizontal stratification also impacts other SBLOCA phenomena such as the offtake phenomenon and the cold leg direct contact condensation phenomenon. For the two-fluid model in the WCOBRA/TRAC-TF2 LOCA safety analysis computer code, a horizontal stratification criterion was developed following the inviscid Kelvin-Helmholtz neutral stability analysis. The horizontal stratification criterion combines the Taitel-Dukler model and the Wallis-Dobson model and captures the test data better. The stratification criterion was assessed against various experimental data with a wide range of pressures and pipe sizes. The stratification criterion also matches well with the transition boundaries predicted by the viscous Kelvin-Helmholtz model. The adequacy of the horizontal stratification model is confirmed by examining the predicted flow regime in a horizontal pipe with the measured data of the high pressure TPTF two-phase flow experiments. The void fractions for the horizontal flow are predicted with a good accuracy, which indicates that the interfacial drag and the wall drag in the two-fluid model are properly modeled and the two-fluid momentum equations with the hydraulic slope term reasonably capture the influence of inlet and outlet boundary conditions expected in the PWR LOCA simulation. © 2015 Elsevier B.V. All rights reserved.


Hatua K.,North Carolina State University | Jain A.K.,General Electric | Banerjee D.,Integrated Electrical Services | Ranganathan V.T.,Indian Institute of Science
IEEE Transactions on Industrial Electronics | Year: 2012

For longer life of alternating-current (ac) machines, it is desirable to feed them by sinusoidal voltages. This can be achieved by connecting an LC filter between the voltage source inverter and the motor. However, the LC filter creates unwanted oscillation at system resonant frequency. A resistance connected in series with the capacitor is a solution to damp out the resonant-frequency oscillation, but this damping technique increases loss in the system. In this paper, a simple active damping technique is proposed for lossless damping of vector-controlled ac motor drives with an LC filter. In the proposed technique, the resistance drop is emulated in the control using the terminal motor voltages. The proposed technique is carried out in the three-phase domain for better accuracy of the control. The proposed technique neither affects the dynamic response of the drive nor changes the design of the standard vector control loops. Results from experimental ac motor drives are presented. © 2011 IEEE.


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