The evaluation of TRACE/PARCS model for BWR-4 nuclear power plant by startup test transient analyses

Generally, the thermal hydraulic (TH) codes need the results of Neutron Kinetics (NK) codes providing the reactivity properties to calculate neutron flux. Then the TH codes perform the safety analyses obtaining the responses of pressure, temperature, or water level. Two kinds of different codes calculate different physical behaviors sequentially and separately. Simultaneously computing thermal hydraulic and neutron kinetics behaviors can enhance the accuracy of the analysis. Hence, it is crucial to develop the TH-NK coupled model. This study presents the capability of the TH-NK coupled model, developed by TRACE (TRAC/RELAP Advanced Computational Engine) and PARCS (Purdue Advanced Reactor Core Simulator), for the BWR-4 nuclear power plant. The establishment of the TRACE/PARCS model presented the nodal and component modeling methodologies. This model was used to simulate two startup tests of high power level system transients. Principal system responses, calculated by the TRACE/PARCS model, were compared with the measured data in startup tests and the results of the point kinetic calculation of the TRACE (TRACE/PK) to evaluate the model. The evaluation shows that the TRACE/PARCS model can simulate the interaction between thermal hydraulic and neutron kinetics phenomena and predict the transients suitably. Through the comparison, the TRACE/PARCS model can be confident doing the analyses of normal and abnormal operational transients to predict the transient responses.

Novel Cascade Diode Lasers Based on Type-I Quantum Wells

A novel approach for cascade diode lasers was developed based on type-I quantum wells (QWs). This design adopted the leaky window effect in the GaSb / InAs band alignment for cascade pumping, and exploits the carriers recycling by the cascade pumping and the high optical gain of the type-I QWs. Two-stage cascade lasers were designed and fabricated for 2.45 and 3.0 μm, demonstrating twofold improvement in the internal efficiency. Record continuous-wave (CW) output power of 1.2 W for 2.45 um and 590 mW for 3.0 um were achieved in room temperature (RT), and the devices operate with higher power conversion efficiency at high power level, compared to conventional single-stage diode lasers.

Enzymatic Inactivation of Oil Palm Fruits: Comparison of Microwave Irradiation and Steam Bath Process

The study on microwave irradiation and steam batch process to sterilize oil palm fruits is carried out to investigate their effectiveness on lipase inactivation. The inactivation parameters, palm oil quality, and stripping efficiency were evaluated. Evaluation on the inactivation parameters, such as decimal reduction time (D-value) and kinetic constant (k), were conducted to study the sterilization dependency on time and temperature. Microwave sterilization required only 14.085 to 16.949 minutes to inactivate lipase at temperature of 76.5°C (max), while steam batch sterilization required more than 90 minutes to obtained similar level of free fatty acid (FFA) at higher temperature (80 to 105°C). The quality of palm oil was indicated by the concentration of FFA in palm oil. Sterilization of either by microwave irradiation or steam batch sterilization reduced lipase’s activity significantly, which is indicated by FFA concentration of below 1%. Stripping efficiency from microwave sterilization at various power level after 16 minutes were 27% (medium power level), 58.5% (medium high power level), and 61% (high power level), respectively.

Research on High-Power Power Factor Corrector of Power Electronic Transformer

Power electronic transformer (PET) which has a big potential application value in smart grid is an electrical power transformer device adopting power electronic converter and high frequency switch transformer. A new PET with power factor correctors (PFC) is proposed in this paper. Due to high power level of PET, PFC should have a high power level as well. Therefore, the multi-phase interleaved PFC is employed. The paper describes the one cycle control principle, proposes a current synthesis method based on IGBT current, and then analyses the relationship between ripple current and duty cycle of IGBT. In addition, the whole PFC system is simulated completely by means of Matlab/Simulink. In order to verify the theoretical analysis and simulation analysis, a four-phase interleaved PFC with a rated output power of 8.0kW is designed and implemented based on the an analog control chip. The obtained results show that the interleaved PFC by means of one cycle control and current synthesis is feasible, capable of reaching a good suppression effect of ripple current.