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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.
Salman Alzahrani (Missouri S&T/KACST), Shoaib Usman (Missouri S&T)
Proceedings | Advances in Thermal Hydraulics 2018 | Orlando, FL, November 11-15, 2018 | Pages 1189-1201
Twisted-tape is one of the most important members of passive heat transfer augmentation techniques for forced convection in many applications. In this paper, a numerical investigation of the heat transfer, pressure drop and secondary flow under the normal operating conditions of the NuScale SMR reactor for sub-channel with and without twisted tape geometry are performed. 3D models for twisted tapes on 2 x 2 rod bundle inside spacer grid fitted was developed. Subsequently, a twisted tapes on 2 x 2 along the entire sub-channel, that spacer grid and the gap between spaces were evaluated through the comparison with no twist tapes and with several twist ratios (p/d = 4.2, 1.7 and 0.85). The results have revealed a strong effect of twist ratios on pressure drop and secondary flow (SF) increases with decreasing twist ratio. Moreover, the Nusselt number (Nu) is increased with Reynolds number (Re) and there is a significant improvement in the Nusselt number when a twisted tape is inserted into the entire sub-channel under the same Reynolds number. For p/d=0.85, heat transfer (Nu) enhancement of 25% and 101% was observed for twisted tapes inside spacer grid and the entire sub-channel respectively. Results showed that the pressure drop with twisted tapes inside spacer grid and the entire sub-channel are influenced by variation of twisted ratio. The highest pressure drop is achieved for the twist ratio of p/d =0.85 which is the lowest twist ratio in this study. Pressure drop showed an almost linear dependence on the twist ratios. Likewise, the secondary flow is observed to be much more pronounced when the entire channel length contained the twisted tape. Interestingly, SF seems to be peaking at the exit point of the spacer grid where the twisted tape ends. SF seems along the entire sub-channel when the entire length contained the tape. The highest SF is achieved for the twisted ratio (p/d =0.85) which is the lowest twist ratio in this study by about SF=.0.16.
