The effect of fuel temperature on the estimation of the moderator temperature coefficient in PWRs

The effect of fuel temperature on the estimation of the moderator temperatu re coefficient of reactivity (MTC) via noise analysis is investigated both theoretically and through numerical simulations. An analytical expression g iving the envelop of the effect is provided. The simulations show that alth ough for typical conditions the effect is small, it is characterized by a g reat deal of uncertainty and in certain occurrences it may become significa nt. The ranges of variation are quantified and the parametric effects are a ddressed. It is found that the induced bias is approximately uniform over a wide range of MTC values. This is supportive to the approach of calibratin g the MTC estimates to the actual MTC values through a constant calibration factor. (C) 1999 Elsevier Science Ltd. All rights reserved.