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01030 Development of a false alarm free, Advanced Loose Parts Monitoring System (ALPS)
05 Nuclear fuels (economics, policy, supplies, forecasts) the project involves the design of a simple state of the art control system for the reactor and a surveillance system based on smart instrumentation and expert system logic. It is noted that there are some physical and experimental problems unique to the MPBR family. These problems are connected with long neutron lifetimes, the need for a new evaluation of kinetic parameters and reactivity effects, and the need for very high sensitivity counting channels.
05101024 Study of the MTC estimation by noise analysis in 2-D heterogeneous systems Demazi~re, C. and Pfizsit, I. Progress in Nuclear Energy, 2003, 43, (1 4), 313-319. The effect of a heterogeneous distribution of the temperature noise on the MTC estimation by noise analysis is investigated. This investigation relies on 2-group diffusion theory, and all the calculations are performed in a 2-D realistic heterogeneous core. It is shown, similarly to the 1-D case, that the main reason of the MTC underestimation by noise analysis compared to its design-predicted value lies with the fact that the temperature noise might not be homogeneous in the core, and therefore using the local temperature noise in the MTC noise estimation gives erroneous results. A new MTC estimator, which was previously proposed for 1-D 1-group homogeneous cases and which is able to take this heterogeneity into account, was extended to 2-D 2group heterogeneous cases. It was proven that this new estimator is always able to give a correct MTC estimation with an accuracy of 3%. This small discrepancy comes from the fact that the reactor does not behave in a point-kinetic way, contrary to the assumptions used in the noise estimators. This discrepancy is however quite small.
05101025 Testing the dynamics of shutdown systems instrumentation in reactor trip measurements GJ6ckler, O. Progress in Nuclear Energy, 2003, 43, (1--4), 91-96. Periodic testing of the dynamics of the shutdown systems and their instrumentation is performed in the C A N D U nuclear power plants of Ontario Power Generation (OPG) and Bruce Power. Measurements of in-core flux detector (ICFD) and ion chamber (I/C) signals responding to the insertion of shut-off rods (shutdown system No. 1, SDS1), or to the injection of neutron absorbing poison (shutdown system No.2, SDS2) are regularly carried out at the beginning of planned outages. A reactor trip is manually initiated at high power and the trip response signals of ICFDs and I/Cs are recorded by multi-channel high-speed high-resolution data acquisition systems set up temporarily at various locations in the station. The sampling of the seaprate data acquisition systems are synchronized through the headset communication systems of the station. A total of 120 station signals can be sampled simultaneously up to 2500 samples per second. The effective prompt fractions of the ICFDs are estimated from the measured trip response. Effectiveness and the timeline of the trip mechanism are assessed in the measurement as well. The measurement can identify ICFDs with abnormally slow response (under-prompt) or overshooting response (over-prompt) at the beginning of the outage. The time required for the signals to drop to predefined fractions of their pre-trip values (level crossing time) is plotted as a function of detector position and compared against safety requirements. The propagating effect of shutoff rod insertion or poison injection on the flux is monitored by the level crossing times of ICFDs and ion chambers.
05/01026 The attractor dimension determination applied to monitoring and surveillance in nuclear power plants Montesino Otero, M. E. et al. Progress in Nuclear Energy, 2003, 43, (14), 389-395. The introduction of non-linear tools in noise analysis has demonstrated its great potential in the surveillance of nuclear reactors and their fundamental equipment, as well as the early detection of anomalies or failures. This paper focuses on the Attractor Dimension Estimation, based on the correlation integral, which is calculated using the Proeaccia and Grassberger procedure. In order to introduce it in a real time monitoring system, a new practical method was suggested founded on the Automated Attractor Dimension Quantitative Estimation (A-AD-QE), using the second derivative of the correlation integral. Time series from the H o p f bifurcation simulation and experimental neutron signals were used for the test of the proposed methods. The applicability of the A-AD-QE method is demonstrated in dynamics which distinguishes periodic and quasi-periodic processes. The results reveal the potential of the A-AD-QE method to be used in systems of surveillance and monitoring in Nuclear Power Reactors.
05101027 Theory of stochastic bifurcation in BWRs and applications Konno, H. et al. Progress in Nuclear Energy, 2003, 43, (t-4), 201-207. The study found that noise destroys the Hopf bifurcation in B W R so that the Lyapunov exponent takes negative values in any case near the onset of power oscillation. Consequently, the values of decay ratio (DR) always take a value less than 1. Theoretical prediction based on
the theory of stochastic bifurcation is verified with the use of practical time series data. A new method of the stochastic dynamics of phasedifference is also proposed, and its powerfulness is demonstrated.
05/01028 a BWR
Time dependence of linear stability parameters of
Navarro-Esbrf, J. et al. Progress in Nuclear Energy, 2003, 43, (l 4), 187-194. In this work several tools are presented to study the time dependence of the linear stability parameters of a B W R using neutron noise analysis. Particularly, the authors have studied the variation in time of the fundamental frequency of a signal using the short-time Fourier transform and compared this method with the calculation of a time dependent Power Spectral Density (PSD) function. The temporal variation of the decay ratio is analysed using a method based on an autoregressive model to fit the different blocks of the signal. The performance of the tools presented is compared analysing analytic signals and a real signal of Forsmark 1&2 Stability Benchmark.
Economics, policy, supplies, forecasts 05/01029 Assessment of human-machine interface design for a Chinese nuclear power plant Chen, X. et al. Reliability Engineering & System Safety, 2005, 87, (1), 37-44. A nuclear power plant (NPP) is a complex system but requires high reliability. The h u m a n - m a c h i n e interface (HMI) design plays very important role in reactor safety. This paper describes an assessment on HMI design of a Chinese NPP, using a software system named Dynamic Interaction Analysis Support (DIAS). DIAS can give not only quantitative indices for dynamically assessing the HMI design, but also allow modify the values of these indices by taking into account h u m a n error probability during specified emergent operation procedures. The operation procedures dealing with postulated accidents and transients recorded from a full-scale plant simulator in the training center of a Chinese NPP were selected as references. According to the results of simulation and analysis, the potential problems in the HMI design and the operation procedures were detected. Suggestions to improve the HMI design and the operation procedures were addressed.
05/01030 Development of a false alarm free, Advanced Loose Parts Monitoring System (ALPS) Pot, G. et al. Progress in Nuclear Energy, 2003, 43, (1-4), 243-251. An Advanced Loose Parts Monitoring System (ALPS) has been developed and installed on each unit of the Paks Nuclear Power Plant, Hungary. ALPS uses sophisticated methods to identify the events hidden in the quite extensive background noise of nuclear power plants. A classification algorithm based on an expert system, which is trained during the start-up period of each fuel cycle, helps to improve the false alarm rate. Thus the false alarm rate was reduced to a minimum, statistically below 1%. In practice, even the remaining 'false alarms' were identified to be originating from other noise sources using ALPS. The main principles of ALPS are presented. It is demonstrated, that even weak signals, comparable with the resolution of the analoguedigital board, i.e. comparable with detection noises, can be identified at high certainty. Other events like vibration of the shaft of motor operated isolating valves have been identified by ALPS. Furthermore, experiences gained during the installation period are also discussed.
05/01031 Development of advanced core noise monitoring system for BWRS Mori, M. et al. Progress in Nuclear Energy, 2003, 43, (1-4), 43-49. A B W R core noise monitoring system is developed for addressing core anomaly problems in future advanced core operation. In order to monitor in-core status from a limited number of signals, various up-todate signal processing algorithms are introduced to compensate for a lack of information. These algorithms, such as independent component analysis, factor analysis and model based parameter estimation, are demonstrated to be effective through real plant data analysis to evaluate core and regional stability index, reactivity coefficients and core flow rate. Through these practices, the study demonstrates that the core noise monitoring system is an effective general platform for providing a variety of monitoring tools to meet the requirements in future advanced core operation.
05•01032 Dynamic reliability and risk assessment of the accident localization system of the Ignalina NPP RBMK-1500 reactor Kopustinskas, V. et al. Reliability Engineering & System Safety, 2005, 87, (1), 77-87.
Fuel and Energy Abstracts May 2005
157
05101024 Study of the MTC estimation by noise analysis in 2-D heterogeneous systems Demazi~re, C. and Pfizsit, I. Progress in Nuclear Energy, 2003, 43, (1 4), 313-319. The effect of a heterogeneous distribution of the temperature noise on the MTC estimation by noise analysis is investigated. This investigation relies on 2-group diffusion theory, and all the calculations are performed in a 2-D realistic heterogeneous core. It is shown, similarly to the 1-D case, that the main reason of the MTC underestimation by noise analysis compared to its design-predicted value lies with the fact that the temperature noise might not be homogeneous in the core, and therefore using the local temperature noise in the MTC noise estimation gives erroneous results. A new MTC estimator, which was previously proposed for 1-D 1-group homogeneous cases and which is able to take this heterogeneity into account, was extended to 2-D 2group heterogeneous cases. It was proven that this new estimator is always able to give a correct MTC estimation with an accuracy of 3%. This small discrepancy comes from the fact that the reactor does not behave in a point-kinetic way, contrary to the assumptions used in the noise estimators. This discrepancy is however quite small.
05101025 Testing the dynamics of shutdown systems instrumentation in reactor trip measurements GJ6ckler, O. Progress in Nuclear Energy, 2003, 43, (1--4), 91-96. Periodic testing of the dynamics of the shutdown systems and their instrumentation is performed in the C A N D U nuclear power plants of Ontario Power Generation (OPG) and Bruce Power. Measurements of in-core flux detector (ICFD) and ion chamber (I/C) signals responding to the insertion of shut-off rods (shutdown system No. 1, SDS1), or to the injection of neutron absorbing poison (shutdown system No.2, SDS2) are regularly carried out at the beginning of planned outages. A reactor trip is manually initiated at high power and the trip response signals of ICFDs and I/Cs are recorded by multi-channel high-speed high-resolution data acquisition systems set up temporarily at various locations in the station. The sampling of the seaprate data acquisition systems are synchronized through the headset communication systems of the station. A total of 120 station signals can be sampled simultaneously up to 2500 samples per second. The effective prompt fractions of the ICFDs are estimated from the measured trip response. Effectiveness and the timeline of the trip mechanism are assessed in the measurement as well. The measurement can identify ICFDs with abnormally slow response (under-prompt) or overshooting response (over-prompt) at the beginning of the outage. The time required for the signals to drop to predefined fractions of their pre-trip values (level crossing time) is plotted as a function of detector position and compared against safety requirements. The propagating effect of shutoff rod insertion or poison injection on the flux is monitored by the level crossing times of ICFDs and ion chambers.
05/01026 The attractor dimension determination applied to monitoring and surveillance in nuclear power plants Montesino Otero, M. E. et al. Progress in Nuclear Energy, 2003, 43, (14), 389-395. The introduction of non-linear tools in noise analysis has demonstrated its great potential in the surveillance of nuclear reactors and their fundamental equipment, as well as the early detection of anomalies or failures. This paper focuses on the Attractor Dimension Estimation, based on the correlation integral, which is calculated using the Proeaccia and Grassberger procedure. In order to introduce it in a real time monitoring system, a new practical method was suggested founded on the Automated Attractor Dimension Quantitative Estimation (A-AD-QE), using the second derivative of the correlation integral. Time series from the H o p f bifurcation simulation and experimental neutron signals were used for the test of the proposed methods. The applicability of the A-AD-QE method is demonstrated in dynamics which distinguishes periodic and quasi-periodic processes. The results reveal the potential of the A-AD-QE method to be used in systems of surveillance and monitoring in Nuclear Power Reactors.
05101027 Theory of stochastic bifurcation in BWRs and applications Konno, H. et al. Progress in Nuclear Energy, 2003, 43, (t-4), 201-207. The study found that noise destroys the Hopf bifurcation in B W R so that the Lyapunov exponent takes negative values in any case near the onset of power oscillation. Consequently, the values of decay ratio (DR) always take a value less than 1. Theoretical prediction based on
the theory of stochastic bifurcation is verified with the use of practical time series data. A new method of the stochastic dynamics of phasedifference is also proposed, and its powerfulness is demonstrated.
05/01028 a BWR
Time dependence of linear stability parameters of
Navarro-Esbrf, J. et al. Progress in Nuclear Energy, 2003, 43, (l 4), 187-194. In this work several tools are presented to study the time dependence of the linear stability parameters of a B W R using neutron noise analysis. Particularly, the authors have studied the variation in time of the fundamental frequency of a signal using the short-time Fourier transform and compared this method with the calculation of a time dependent Power Spectral Density (PSD) function. The temporal variation of the decay ratio is analysed using a method based on an autoregressive model to fit the different blocks of the signal. The performance of the tools presented is compared analysing analytic signals and a real signal of Forsmark 1&2 Stability Benchmark.
Economics, policy, supplies, forecasts 05/01029 Assessment of human-machine interface design for a Chinese nuclear power plant Chen, X. et al. Reliability Engineering & System Safety, 2005, 87, (1), 37-44. A nuclear power plant (NPP) is a complex system but requires high reliability. The h u m a n - m a c h i n e interface (HMI) design plays very important role in reactor safety. This paper describes an assessment on HMI design of a Chinese NPP, using a software system named Dynamic Interaction Analysis Support (DIAS). DIAS can give not only quantitative indices for dynamically assessing the HMI design, but also allow modify the values of these indices by taking into account h u m a n error probability during specified emergent operation procedures. The operation procedures dealing with postulated accidents and transients recorded from a full-scale plant simulator in the training center of a Chinese NPP were selected as references. According to the results of simulation and analysis, the potential problems in the HMI design and the operation procedures were detected. Suggestions to improve the HMI design and the operation procedures were addressed.
05/01030 Development of a false alarm free, Advanced Loose Parts Monitoring System (ALPS) Pot, G. et al. Progress in Nuclear Energy, 2003, 43, (1-4), 243-251. An Advanced Loose Parts Monitoring System (ALPS) has been developed and installed on each unit of the Paks Nuclear Power Plant, Hungary. ALPS uses sophisticated methods to identify the events hidden in the quite extensive background noise of nuclear power plants. A classification algorithm based on an expert system, which is trained during the start-up period of each fuel cycle, helps to improve the false alarm rate. Thus the false alarm rate was reduced to a minimum, statistically below 1%. In practice, even the remaining 'false alarms' were identified to be originating from other noise sources using ALPS. The main principles of ALPS are presented. It is demonstrated, that even weak signals, comparable with the resolution of the analoguedigital board, i.e. comparable with detection noises, can be identified at high certainty. Other events like vibration of the shaft of motor operated isolating valves have been identified by ALPS. Furthermore, experiences gained during the installation period are also discussed.
05/01031 Development of advanced core noise monitoring system for BWRS Mori, M. et al. Progress in Nuclear Energy, 2003, 43, (1-4), 43-49. A B W R core noise monitoring system is developed for addressing core anomaly problems in future advanced core operation. In order to monitor in-core status from a limited number of signals, various up-todate signal processing algorithms are introduced to compensate for a lack of information. These algorithms, such as independent component analysis, factor analysis and model based parameter estimation, are demonstrated to be effective through real plant data analysis to evaluate core and regional stability index, reactivity coefficients and core flow rate. Through these practices, the study demonstrates that the core noise monitoring system is an effective general platform for providing a variety of monitoring tools to meet the requirements in future advanced core operation.
05•01032 Dynamic reliability and risk assessment of the accident localization system of the Ignalina NPP RBMK-1500 reactor Kopustinskas, V. et al. Reliability Engineering & System Safety, 2005, 87, (1), 77-87.
Fuel and Energy Abstracts May 2005
157