Influences of the covariance matrices over reactor neutron dosimetry

Present status and influences of three convariance matrices being used in reactor neutron dosimetry have been reviewed. Those are the uncertainties of the measured reaction-rate values, dosimeter reaction cross-section values and guess spectra, and are essential to the uncertainty analysis of the present dosimetry results. Immediate needs are stated to establish the evaluation method of covariance matrices of the cross-section curves and to decrease their uncertainties, which have rather low accuracies than the measured reaction-rate values although these two have the same influences to the final results. Conclusive remarks have been said that we can't go forward without covariance matrices of cross-section and guess-spectrum at least in the next 10 years, and interesting comments are given through numerical unfolding results that the covariance matrices of guess spectra have generally very favorable influences of dosimetry results which make larger the inititial error of the calculated reaction-rate and make lower the final uncertainty of integral dose values. (author)