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The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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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.
Anil Kumar, M. Srinivasan, K. Subba Rao
Nuclear Science and Engineering | Volume 84 | Number 2 | June 1983 | Pages 155-164
Technical Note | doi.org/10.13182/NSE83-A17722
Articles are hosted by Taylor and Francis Online.
The Trombay criticality formula (TCF) has been derived by incorporating a number of well-known concepts of criticality physics to enable prediction of changes in critical size or keff following alterations in geometrical and physical parameters of uniformly reflected small reactor assemblies characterized by large neutron leakage from the core. The variant parameters considered are size, shape, density and diluent concentration of the core, and density and thickness of the reflector. The mass-to-surface-area ratio of the core, is essentially a measure of the product ρr extended to nonspherical systems and plays a dominant role in the TCF. The functional dependence of keff on σ/σc, the system size relative to critical, is expressed in the TCF through two alternative representations, namely the modified Wigner rational form and the exponential form as follows: where is the k∞ of the critical system. The quantity in the square brackets is close to unity and Z is a parameter weakly dependent on both the physical and geometrical properties of the core, where θ = ln[/( - 1)] and ε is a parameter introduced to account for the steep rise in the net leakage probability for highly subcritical cores. The applications of the TCF range from the quick computation of the keff of a lump of fissile fuel having arbitrary shape and density through the study of keff of highly enriched fissile materials during transportation accidents to an estimation of the void and fuel expansion coeffficients of reactivity in high leakage systems.