Cellules solaires photovoltaïques plastiques enjeux et perspectives

Après avoir détaillé le fonctionnement d'une cellule photovoltaïque plastique et les paramètres photovoltaïques permettant de caractéiser son efficacité, un état de l'art des technologies de fabrication des cellules est présenté. Des moyens d'amélioration des performances des cellules photovoltaïques organiques sont ensuite illustrés par l'étude de dispositifs développés au Laboratoire Composants Organiques (LCO) du CEA Saclay

Sodium fast reactor power monitoring using fluorine 20 tagging agent

International audienceThis work deals with the use of gamma spectrometry to monitor the fourth generation of sodium fast reactor (SFR) power. Simulation part has shown that power monitoring in short response time and with good accuracy is possible measuring liquid sodium delayed gamma emitters produced in-core. An experimental test is under preparation at French SFR Phénix experimental reactor to validate simulation studies. Physical calculations have been done to correlate gamma activity to the released thermal power. Gamma emitter production rate in the reactor core was calculated with technical and nuclear data as sodium velocity, atomic densities, neutron spectra and incident neutron cross-sections of reactions producing gamma emitters. Then, a thermal hydraulic transfer function was used for taking into account primary sodium flow in our calculations and gamma spectra were determined by Monte-Carlo simulations. For power monitoring problematic, use of a short decay period gamma emitter will allowed to obtain a very fast response system without cumulative and flow distortion effects. The experiment will be set during the reactor "end of life testing". The Delayed Neutron Detection (DND) system cell has been chosen as the best available primary sodium sample for gamma power monitoring on Phénix reactor due to its short transit time from reactor core to measurement sample and homogenized sampling in the reactor hot pool. The main gamma spectrometer is composed of a coaxial high purity germanium diode (HPGe) coupled with a transistor reset preamplifier. The signal will be then processed by a digital signal processing system (called Adonis) which is optimum for high count rate and various time activity measurements. To limit statistical problems of the signal, an analytical pileup correction method using duration variable given by our spectrometry system Adonis) and a nonparametric Bayesian inference for photopeack deconvolution will be used

Sodium fast reactor power monitoring using fluorine 20 tagging agent

International audienceThis work deals with the use of gamma spectrometry to monitor the fourth generation of sodium fast reactor (SFR) power. Simulation part has shown that power monitoring in short response time and with good accuracy is possible measuring liquid sodium delayed gamma emitters produced in-core. An experimental test is under preparation at French SFR Phénix experimental reactor to validate simulation studies. Physical calculations have been done to correlate gamma activity to the released thermal power. Gamma emitter production rate in the reactor core was calculated with technical and nuclear data as sodium velocity, atomic densities, neutron spectra and incident neutron cross-sections of reactions producing gamma emitters. Then, a thermal hydraulic transfer function was used for taking into account primary sodium flow in our calculations and gamma spectra were determined by Monte-Carlo simulations. For power monitoring problematic, use of a short decay period gamma emitter will allowed to obtain a very fast response system without cumulative and flow distortion effects. The experiment will be set during the reactor "end of life testing". The Delayed Neutron Detection (DND) system cell has been chosen as the best available primary sodium sample for gamma power monitoring on Phénix reactor due to its short transit time from reactor core to measurement sample and homogenized sampling in the reactor hot pool. The main gamma spectrometer is composed of a coaxial high purity germanium diode (HPGe) coupled with a transistor reset preamplifier. The signal will be then processed by a digital signal processing system (called Adonis) which is optimum for high count rate and various time activity measurements. To limit statistical problems of the signal, an analytical pileup correction method using duration variable given by our spectrometry system Adonis) and a nonparametric Bayesian inference for photopeack deconvolution will be used

Sodium Fast Reactor Power Monitoring and Clad Failure Detection using Adonis System

On sodium fast reactors, power is usually measured by heat balance on water to vapor heat exchangers which is correlated with the ex-core neutron flux measurements. The ex-core neutron power measurement is done by fission chambers (five on the French SFR Phnix reactor) with several activity ranges settled at the bottom of the primary vessel to cover the whole neutron flux range of more than 11 decades. This measurement instantly estimates the neutron power but induces some shift problems. The clad failure detection is done by gamma measurement on argon cover gas sampling and neutron measurement on primary sodium sample. This work deals with the use of gamma spectrometry for fourth generation SFR power monitoring and clad failure detection. Usually gamma spectrometers could not manage on-line application but recent improvements in this research field may improve it. The Adonis digital signal processing prototype gives a time function response and is able to do spectrometry measurement with metrological grade under high gamma flux impinging the HPGe detector, with also high and fast activity transient. Previous works on Pressurized Water Reactors (PWR) show that gamma emitter concentration in primary coolant is also directly correlated with reactor neutron power. On SFR, the use of short decay period gamma emitters as the 20F and 23Ne tagging agent will allow a very fast response system without thermal hydraulic distortion effects. The study is divided in two parts. First part deals with a simulation study based on physical calculations and MCNP simulations to predict sensor signal as a function of neutron power. The second part is an experimental test under preparation at the French SFR Phnix. Measuring activation and fission products contained in primary sodium, the adaptive Adonis system set on primary coolant sample could be an innovating neutron power monitoring and clad failure detection system for SFR

20F Power Measurement for Generation IV Sodium Fast Reactors

International audienceThe Phénix nuclear power plant has been a French Sodium Fast Reactor (SFR) prototype producing electrical power between 1973 and 2010. The power was monitored using ex-core neutron measurements. This kind of measurement instantly estimates the power but needs to be often calibrated with the heat balance thermodynamic measurement. Large safety and security margins have then been set not to derive above the nominal operating point. It is important for future SFR to reduce this margin and working closer to the nominal operating point. This work deals with the use of delayed gamma to measure the power. The main activation product contained in the primary sodium coolant is the 24Na which is not convenient for neutron flux measurement due to its long decay period. The experimental study done at the Phénix reactor shows that the use of 20F as power tagging agent gives a fast and accurate power measurement closed to the thermal balance measurement thanks to its high energy photon emission (1.634 MeV) and its short decay period (11 s)

Delayed gamma power measurement for sodium-cooled fast reactors

Previous works on pressurized water reactors show that the nitrogen 16 activation product can be used to measure thermal power. Power monitoring using a more stable indicator than ex-core neutron measurements is required for operational sodium-cooled fast reactors, in order to improve their economic efficiency at the nominal operating point. The fluorine 20 and neon 23 produced by (n,α) and (n,p) capture in the sodium coolant have this type of convenient characteristic, suitable for power measurements with low build-up effects and a potentially limited temperature, flow rate, burn-up and breeding dependence. This method was tested for the first time during the final tests program of the French Phénix sodium-cooled fast reactor at CEA Marcoule, using the ADONIS gamma pulse analyzer. Despite a non-optimal experimental configuration for this application, the delayed gamma power measurement was pre-validated, and found to provide promising results