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Fusion Science and Technology
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Getting back to yes: A local perspective on decommissioning, restart, and responsibility
For 45 years, Duane Arnold Energy Center operated in Linn County, Ia., near the town of Palo and just northwest of Cedar Rapids. The facility, owned by NextEra Energy, was the only nuclear power plant in the state.
In August 2020, a historic derecho swept across eastern Iowa with winds approaching 140 miles per hour. Damage to the plant’s cooling towers accelerated a shutdown that had already been planned, and the facility entered decommissioning soon after, with its fuel removed in October of that year. Iowa’s only nuclear plant had gone off line.
Today the national energy landscape looks very different than it did just six short years ago. Electricity demand is rising rapidly as data centers, artificial intelligence infrastructure, advanced manufacturing, and electrification expand across the country. Reliable, carbon-free baseload power has become increasingly valuable. In that context, Linn County has approved the rezoning necessary to support the recommissioning and restart of Duane Arnold and is actively supporting NextEra’s efforts to secure the remaining state and federal approvals.
W. J. Chen, D. L. Yu, L. W. Yan, B. S. Yuan, X. X. He, L. Liu, Y. L. Wei, N. Zhang, X. F. He, H. Wu, Z. B. Shi, Y. Liu, Q. W. Yang
Fusion Science and Technology | Volume 76 | Number 1 | January 2020 | Pages 37-44
Technical Paper | doi.org/10.1080/15361055.2019.1629251
Articles are hosted by Taylor and Francis Online.
In order to reconstruct the plasma current density, the Current Profile Fitting (CPF) code has been successfully developed on the HL-2A tokamak. A seven-channel motional Stark effect (MSE) diagnostic based on dual photoelastic modulators is installed to measure the pitch angle of the magnetic field, which can be used as an internal magnetic field constraint for the CPF code. Recently, the MSE polarimeter was upgraded with a real-time wavelength matching system to improve the signal-to-noise ratio. The magnetic field angle (γpitch) with a temporal resolution of 10 ms can be provided. In the CPF code, the plasma current density is described as a polynomial, and the Least-Squares method is used to determine the coefficients of the polynomial. The Finite Difference method and the Strongly Implicit Procedure method are used to solve the Grad-Shafranov equation. The code operation is stable. With the improved-quality MSE data, the CPF calculation result of shot 30782 suggests that the safety factor q profile is monotonic. The minimum q value is less than 1 on-axis during sawtooth oscillations in shot 30782. And, the position of the q = 1 surface is consistent with the sawtooth inversion radius measured by electron cyclotron emission and soft X-ray diagnostics.
