Periodic evaluation of operational experience

Periodic evaluation of operational experience should be performed, including periodic review and analysis of operations, surveillance, testing and maintenance records and reports. This is to ensure that all data which has been collected will be taken into account during analysis of the safety state of the facility. Also the operation and maintenance procedures should be modified to compensate for changes due to ageing. 

The periodic evaluation of operating experience should be done systematically. It is advisable to have a permanent forum of experts (e.g. the safety conunittee) to do these evaluations on a prescribed schedule. 

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Operating conditions (or modes) have already been defined as part of service conditions which affect ageing processes. Periodic evaluation of operational experience may reveal the need to change operating conditions such as operation mode, core arrangements and chemical parameters of fluid. 

The desired purity for the experiment reported below was set to 55.0% and the controller was started at the 60th period. Figure 7.47 shows the evaluation of the product purity as well as of the controlled variables. In the open loop mode where the operating point was calculated based on the initial model, the... 

Such calibrations can also be performed on temperature ramps or while chemical reactions are still in progress, provided that the correct, generally valid unsteady-state heat balance corresponding to the mode of operation is used for their evaluation. In these cases, however, it becomes crucial that in the period of time shortly before and shortly after the calibration heater is in use no significant dynamic effects occur, as these times are used to determine initial and final state of the system. The course of a typical experiment including the calibration phases is shown in Figure 4-68. 

Owing to the periodic monitoring of valves including actuators and the evaluation of the measured data by ADAM the actual conditions of the valve can be determined to ensure the readiness for function. Based on the information obtained from ADAM and operational experience over a longer time period a condition-based maintenance can be performed in order to extend the maintenance periods. That means, preventive measures as inspections and replacement of parts can be reduced. 

In the meantime, the operational experience could be significantly expanded. The operational experience of the operating 17 nuclear power plants in Germany for the period up to the end of December 2010 has been completely evaluated. Since the amount of data has increased the use of foreign operating experience in the determination of CCF probabilities is no longer necessary. 

The annual radiation exposure of nuclear workers is limited to 5rem, and sites for nuclear operations are selected so that in the event of the maximum credible accident the exposure of the public will be less than 25 rem. The levels of radiation exposure were first established on the basis of historical data, and since then they have been periodically evaluated by the International Commission on the basis of continuing experience. 

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