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New laws offer nuclear industry incentives for existing power plant uprates
This year, the U.S. nuclear industry received a much-needed economic boost that could help preserve operating nuclear power plants and incentivize upgrades that extend their lifespan and power output.
Signed into law in 2022, the Inflation Reduction Act offers production tax credits (PTCs) for existing nuclear power plants and either PTCs or investment tax credits (ITCs) for new carbon-free generation. These credits could make power uprates—increasing the maximum power level at which a commercial plant may operate—a much more appealing option for utilities.
A. Alapour, R. A. Karam
Nuclear Science and Engineering | Volume 79 | Number 3 | November 1981 | Pages 278-298
Technical Paper | doi.org/10.13182/NSE81-A19405
Articles are hosted by Taylor and Francis Online.
It is commonly accepted that the resonance reaction rate of any material increases when the temperature is raised. Using an exact Doppler-broadening kernel based on the Maxwellian distribution of nuclear velocities and an accurate integral transport method, we have shown that in a nuclear reactor the increase in resonance reaction rates with temperature at relatively high energy shifts the fine structure neutron spectrum in such a way that a net decrease in the neutron flux results at lower energies. In fast reactors, the decrease in the neutron flux at lower energy becomes more than the decrease in the self-shielding due to Doppler broadening and the net effect is a decrease in the resonance reaction rates. The quantification of the various components of the Doppler coefficient, T(dk/dT), in the liquid-metal fast breeder reactor benchmark (zero power reactor-6 Assembly 7) reveals that the spectral shift induced primarily by the broadening of 238U resonances causes the fissile material, 239Pu, to have a large negative (not positive) Doppler effect, which is 38% of the total. This prompt negative feedback indicates that prorating the Doppler signal by summing the Doppler contribution from each isotope based on first-order perturbation can lead to an error in the transient analysis. Calculation of the natural UO2 sample Doppler worth in this assembly, in which the spectral shift effects are included, gives good agreement with the measured value.