A post-Ko study of parametric reactor NAA is described including the determination and applications of working KoS for non-1/V reactions151Eu(n,)152Eu and176Lu(n,)177Lu; parametric corrections for235U fission, threshold reaction and -spectral interferences; and parametric normalizations for different counting geometries. The analytical significance, the principles, the experimental confirmations, and the application examples of these methods are briefly introduced.