Analysis and Design of a 333 MWth Marine PWR Core using Mixed D₂O-H₂O Coolant and Thorium-Based Checkerboard Micro-Heterogeneous and All-Uranium Fuel


In this reactor physics study, we attempt to design a soluble-boron-free (SBF) PWR civil marine reactor core that can operate over a 20 effective-full-power-years life at 333 MWth using mixed D2O-H2O coolant. We use WIMS to develop subassembly designs and PANTHER to examine whole-core arrangements, optimizing: subassembly and core geometry; fuel enrichment; burnable and moveable poison design; and whole-core loading patterns. In this study, we use 15% U-235 enriched UO2 and 18% enriched micro-heterogeneous ThO2-UO2 duplex fuel arranged in a simple checkerboard configuration. Comparisons are made between the homogeneously mixed 15% U-235 enriched all-UO2 case and the checkerboard configuration with high thickness ZrB2 integral fuel burnable absorber pins for reactivity control. Taking advantage of self-shielding effects, the checkerboard option shows greater promise in the final burnable poison design while maintaining low, stable reactivity with minimal burnup penalty. For the final poison design with ZrB2, the checkerboard contributes 2.5% more initial reactivity suppression, although the all-UO2 design exhibits lower reactivity swing. All the candidate materials show greater rod worth for the checkerboard design. For both fuels, B4C has the highest reactivity worth, providing 3% higher control rod worth for checkerboard fuel than all-UO2 . Finally, optimized assemblies were loaded into a 3D reactor model in PANTHER. The PANTHER results show that the designed cores can achieve the target core lifetime of 20 years, confirming the fissile loading is well-designed.

Meeting Name

2016 International Congress on Advances in Nuclear Power Plants, ICAPP 2016 (2016: Apr. 17-20, San Francisco, CA)


Nuclear Engineering and Radiation Science

Keywords and Phrases

Coolants; Design; Nuclear energy; Nuclear power plants; Pressurized water reactors; Reactor shielding; Candidate materials; Control rod worth; Effective full power years; Loading patterns; Micro-heterogeneous; Reactivity control; Reactivity worth; Self shielding effect; Fuels

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Document Type

Article - Conference proceedings

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© 2016 American Nuclear Society (ANS), All rights reserved.

Publication Date

01 Apr 2016