Estimation of the Moderator Temperature Coefficient (Analysis of an MTC measurement using boron dilution method)

Paper in proceeding, 2000

The boron dilution method is analyzed, which is widely used for Moderator Temperature Coefficient (MTC) measurement in Pressurized Water Reactors (PWRs). Data were taken from the measurement of the at-power MTC at the PWR Unit 4 of the Ringhals Nuclear Power Plant (Sweden) during fuel cycle 16 at 300 ppm. Detailed calculations were made to estimate all reactivity effects. Calculations were performed with the static code SIMULATE-3, and error limits were also estimated. The analysis showed that the contribution from the Doppler correction was almost negligible, whereas the reactivity correction due to effects other than the Doppler and the boron effects were surprisingly significant. It was found that the uncertainty associated with the boron dilution method could be larger than previously expected.