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November 9–12, 2025
Washington, DC|Washington Hilton
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House, Senate bills aim to improve nuclear decommissioning and waste disposal
Two bills were introduced in the last several weeks aiming to address nuclear power at the end of life—decommissioning plants and recycling used fuel.
Yasushi Seki
Nuclear Science and Engineering | Volume 51 | Number 2 | June 1973 | Pages 243-251
Technical Note | doi.org/10.13182/NSE51-243
Articles are hosted by Taylor and Francis Online.
The perturbation formula introduced by Gandini for calculation of a nuclear reactivity change in second-order accuracy is modified to permit its wide applicability. It is shown that the formula could give the second-order perturbation terms for the respective reaction components. Application of the formula and its calculation method are described.