SCW Facilities Installed in JRC Petten - Past, Present and Future

Currently there are three SCW loops installed and operated in JRC IE Petten for different kind of tests such as SSRT (Slow Strain Rate Tests), Crack Growth Rate and CER (Contact Electric Resistance). In summer 2010, a new SCW loop built by Cormet was installed in JRC IE Petten. The main difference to first generation of SCW loops manufactured by Cormet consists in new two phase het exchanger and pre-heater system which allows reaching up to 20 l/h water flow even at the maximum parameters. First tests were focused on evaluation of the chemistry control at the maximum reachable parameters loop can achieve especially how effectively the oxygen dosed into the system can be controlled. Conclusions comparing the same conditions of the tests by using first generation of SCW loops and the new one are presented. By-pass system installed in high pressure part of the loop allows attachment of different loading devices based on pneumatic bellows technology. The first built prototype, which was developed during common JRC&VTT exploratory research project ¿Miniature Size Autoclave Bellows', is described in this paper.JRC.DDG.F.4-Safety of future nuclear reactor

Reliability of electrochemical noise measurements: Results of round-robin testing on electrochemical noise

Sixteen laboratories have performed electrochemical noise (EN) measurements based on two systems. The first uses a series of dummy cells consisting of a “star” arrangement of resistors in order to validate the EN measurement equipment and determine its baseline noise performance, while the second system, based on a previous round-robin in the literature, examines the corrosion of aluminium in three environments. All participants used the same measurement protocol and the data reporting and analysis were performed with automatic procedures to avoid errors. The measurement instruments used in the various laboratories include commercial general-purpose potentiostats and custom-built EN systems. The measurements on dummy cells have demonstrated that few systems are capable of achieving instrument noise levels comparable to the thermal noise of the resistors, because of its low level. However, it is of greater concern that some of the instruments exhibited significant artefacts in the measured data, mostly because of the absence of anti-aliasing filters in the equipment or because the way it is used. The measurements on the aluminium samples involve a much higher source noise level during pitting corrosion, and most (though not all) instruments were able to make reliable measurements. However, during passivation, the low level of noise could be measured by very few systems. The round-robin testing has clearly shown that improvements are necessary in the choice of EN measurement equipment and settings and in the way to validate EN data measured. The results emphasise the need to validate measurement systems by using dummy cells and the need to check systematically that the noise of the electrochemical cell to be measured is significantly higher than the instrument noise measured with dummy cells of similar impedance.JRC.F.4-Innovative Technologies for Nuclear Reactor Safet

Reliability of electrochemical noise measurements: Results of round-robin testing on electrochemical noise

Sixteen laboratories have performed electrochemical noise (EN) measurements based on two systems.The first uses a series of dummy cells consisting of a “star” arrangement of resistors in order to validatethe EN measurement equipment and determine its baseline noise performance, while the second sys-tem, based on a previous round-robin in the literature, examines the corrosion of aluminium in threeenvironments. All participants used the same measurement protocol and the data reporting and analysiswere performed with automatic procedures to avoid errors. The measurement instruments used in thevarious laboratories include commercial general-purpose potentiostats and custom-built EN systems.The measurements on dummy cells have demonstrated that few systems are capable of achieving instru-ment noise levels comparable to the thermal noise of the resistors, because of its low level. However, itis of greater concern that some of the instruments exhibited significant artefacts in the measured data,mostly because of the absence of anti-aliasing filters in the equipment or because the way it is used.The measurements on the aluminium samples involve a much higher source noise level during pittingcorrosion, and most (though not all) instruments were able to make reliable measurements. However,during passivation, the low level of noise could be measured by very few systems. The round-robin test-ing has clearly shown that improvements are necessary in the choice of EN measurement equipmentand settings and in the way to validate EN data measured. The results emphasise the need to validatemeasurement systems by using dummy cells and the need to check systematically that the noise of theelectrochemical cell to be measured is significantly higher than the instrument noise measured withdummy cells of similar impedance.JRC.F.4-Innovative Technologies for Nuclear Reactor Safet