Abstract and subjects
The moderator-temperature coefficient of reactivity (MTC) is an important parameter in safety analyses for thermal reactors. A positive MTC can exacerbate the severity of heatup transients, while a negative MTC can worsen the severity of cooldown transients. In particular, a strongly negative MTC is the major determinant of the severity of a steam-line break accident for pressurized water reactors (PWRs). Conversely, positive and negative MTCs can mitigate the severity of cooldown and heatup transients, respectively. Consequently, the accurate measurement and prediction of MTCs is an important factor in demonstrating that some reactors types, especially PWRs, can be operated safely.