[en] Experimental measurements of the uniform temperature coefficients of the NRX reactor, for both moderator and rod-assembly temperature changes are examined. The results of these are combined. The agreement of Calculated and Experimental values of the uniform temperature coefficient is better than the accuracy of the data used in the calculations would warrant. In Part B experimental measurements of the uniform temperature coefficient of a Zeep lattice are compared with the calculated values. There is good agreement between calculations and experiment. For lattices of this type, with relatively large values of K² , the leakage terms dominate the contributions to the temperature coefficient. Large corrections are required for changes of radial and vertical extrapolation lengths. (author)