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2025 ANS Winter Conference & Expo
November 8–12, 2025
Washington, DC|Washington Hilton
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Latest News
DNFSB’s Summers ends board tenure, extending agency’s loss of quorum
Lee
Summers
The Defense Nuclear Facilities Safety Board, the independent agency responsible for ensuring that Department of Energy facilities are protective of public health and safety, announced that the board’s acting chairman, Thomas Summers, has concluded his service with the agency, having completed his second term as a board member on October 18.
Summers’ departure leaves Patricia Lee, who joined the DNFSB after being confirmed by the Senate in July 2024, as the board’s only remaining member and acting chair. Lee’s DNFSB board term ends in October 2027.
John Loberg, Michael Österlund, Klaes-Håkan Bejmer, Jan Blomgren, Jesper Kierkegaard, Sten-Örjan Lindahl
Nuclear Science and Engineering | Volume 167 | Number 3 | March 2011 | Pages 221-229
Technical Paper | doi.org/10.13182/NSE09-105
Articles are hosted by Taylor and Francis Online.
Models of the neutron flux shape in a withdrawn control rod in a boiling water reactor (BWR) bottom reflector have been constructed from simulations with the Monte Carlo code MCNP. These neutron flux models are intended for determining absorber depletion and fast fluence accumulation for withdrawn control rods with nodal codes.So-called G-factors are created for coupling the neutron flux models to a conventional nodal code via the core bottom neutron flux.The neutron flux models and G-factors are created for three different neutron energies, and their dependence on various parameters such as blanket enrichments, Hf and B4C control rod absorber, and depletion and reflector geometry is investigated.The neutron flux models and G-factors are found to be very insensitive; the neutron flux models predict the simulated neutron flux in the withdrawn control rod from MCNP over a variety of reflector configurations with an error < 3.0%. This implies that the neutron flux models constructed in this paper are generally applicable for BWR reflectors and control rods not fundamentally deviating from the designs investigated in this paper.
