Improvements in Measuring Equipment

Summary

The three years of operational experience with the measurement equipment of the SSPS-CRS has demonstrated that three main areas need improvement:

• 1. The measurement sensors should be calibrated periodically to guarantee the availability and accuracy of the measurements.

• 2. Additional measurement equipment should be installed to separate the measurement sensors from the control sensors and to allow measurement of the beam quality of all the heliostats, optical power into the cavity, spillage losses, and the stair-step of the circumsolar factor by hand.

• 3. The control and measuring systems should be separated completely, and control and data evaluation programs installed in their own computers. The data acquisition system should have its own front-end computer to receive the data evaluation of the measurements.

The appendix of the report contains the results of two calibration campaigns on the thermocouples and flowmeters. The examination of 12 relevant thermocouples resulted in deviations somewhat above the guaranteed tolerance of the NiCr-Ni sensors used. But with the help of the described polynominal and special coefficients for every thermocouple, these deviations can be corrected. The examination of the most important flowmeter, LK01CF01 of the sodium circuit, resulted in deviations in the range of 2.79% up to 11.29% less displayed. The deviation depends on the absolute value of the flow in m³/hr.

The deviations stated are much higher than the expected inaccuracy of ± 2.5% over the whole measuring range. This flowmeter has been exchanged for a new, exact calibrated one.