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60 Years of U: Perspectives on resources, demand, and the evolving role of nuclear energy
Recent years have seen growing global interest in nuclear energy and rising confidence in the sector. For the first time since the early 2000s, there is renewed optimism about the industry’s future. This change is driven by several major factors: geopolitical developments that highlight the need for secure energy supplies, a stronger focus on resilient energy systems, national commitments to decarbonization, and rising demand for clean and reliable electricity.
O. E. Dwyer
Nuclear Science and Engineering | Volume 25 | Number 4 | August 1966 | Pages 343-358
Technical Paper | doi.org/10.13182/NSE66-A18553
Articles are hosted by Taylor and Francis Online.
Circumferential variations of temperature and local heat transfer coefficients were obtained for sodium flowing in-line through a staggered rod bundle. The conditions of the study were: turbulent flow, uniform heat flux from the surfaces of all rods, and fully developed velocity and temperature profiles. The rods were spaced in an equilateral triangular array, and the pitch:diameter (P:D) ratio was varied down to 1.10. It was shown that the annulus model is satisfactory for estimating average heat transfer coefficients for P:D ratios down to about 1.3, but below this, it gives increasingly high results, e.g., at P:D = 1.10, an annulus-model coefficient can be high by about a factor of 2. It was found that circumferential temperature variations are not large, e.g., at P:D = 1.10, this variation is about twice the average temperature drop from the rod surface to flowing metal. Compared to the P:D ratio, the Peclet number has little influence on the reduction in the average heat transfer coefficient, or the circumferential variation of the surface temperature. At a P:D ratio of 1.40, the local coefficient is estimated to vary by a factor of only 1.2; at 1.20, by a factor of 1.7; and at 1.10, by a factor of ≈ 100.