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Process Improvements in Control Rod Calibrations. P. M. Whaley Kansas State University. Excess reactivity Shutdown margin (reactive rod out) React. Addition Rate Pulse rod worth. $2.50 $1.10 $0.087/s $2.00 (nominal). Reactivity Limits. Rod calibration. Calibration methods.
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Process Improvements inControl Rod Calibrations P. M. Whaley Kansas State University
Excess reactivity Shutdown margin (reactive rod out) React. Addition Rate Pulse rod worth $2.50 $1.10 $0.087/s $2.00 (nominal) Reactivity Limits
Calibration methods • Positive Period • More accurate in differential worth • More likely to propagate in integral worth • Rod Drop • Accuracy satisfactory for additions < $2.00 • K-State uses either: • Both methods covering full scale, or • Verification of worth if rods > $2.00 full out
Calibration PROCESS Critical START Program Drop Rod • DAC collection • Coordinate manually • Coordinate in a VI • 6-second buffer loop Collect Data Write data to file (3) VI Senses Rod Drop (4) Stores Buffer & Subsequent Data STOP VI
Calibration PROCESS (2) Import to Excel Find Drop Normalize to pre-drop average Time Scale Select & plot points Average & Error analysis Extrapolate
Issues & Problems • Time • Analysis • Days to collect data • Followed by days to analyze data • Identifying erroneous data • Anomalous data cannot be corrected real-time • Human factors not optimal in the process • Plotting • Extrapolating • It’s going to get worse
Data Collection Critical START VI Drop Rod VI notes stability VI records continuously Write data to file VI Collects Data STOP recording
Pre-Analysis Specify File Find Drop Select Tolerance Normalize to pre-drop average Option Manual
Analysis Specify Analysis Start & Stop Interpolate Data Calculate Mean & Standard Dev
Matrix • Power fractions, ASCI II files Time Reactivity Fraction • Differential equations for inhour equation • Matlab solution • Parameters from Hazard Summary Report
For the Future • Evaluate sensitivity of measurement • Current measurements are satisfactory • HSR method uses β vice β-effective • HSR method uses l for aluminum fuel vice SS • Any changes subject to 10CFR50.59 • Measure kinetics parameters • White noise experiments • Pile oscillator • Determine if adjustments can be made to improve accuracy for large reactivity additions
Acknowledgement SMART Laboratory Personnel • Tyler Krehbiel (LabView Programming) • Mark Harrison (Calculations)