[en] A second-order error analysis of the LOFT secondary calorimetric power equation was performed to determine a figure for system accuracy for use in safety analysis and program evaluation. A realistic figure of accuracy for the Secondary Coolant System (SCS) was developed reflecting the relative importance of each measured parameter. This analysis was performed using SOERP, a second-order error propagation computer code. The final 2sigma tolerance band on calculated calorimetric power was found to be 0.720% of the mean calculated power in the full power (55MW) range. The second order error analysis contained in this report is valid provided the following assumptions are met: (1) SCS is at steady state, and (2) errors in instruments are normally distributed