Details

Autor(en) / Beteiligte

• Orlandi, Horus Ibrahim
• Rossi, Pedro Carlos Russo
• Braid, Adolfo Aguiar
• Moreira, João Manoel Losada

Titel

Fuel element microreactor integrating a square UO2 fuel rod with an internal heat pipe

Ist Teil von

• Nuclear engineering and design, 2024-07, Vol.423, p.113205, Article 113205

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2024

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• •Special fuel elements based on square fuel rods having an internal heat pipe.•Use of square lattice to increase the fuel content per fuel element, increase total core reactivity and keep the core compact.•Mercury heat pipe reactor to reduce overall core temperature.•Compact micro reactor core approximating an octahedron with 60 cm height by 60 cm equivalent diameter.•Ratio between thermal power and fuel mass of 2.46 kW/kgU. In this study we propose the Fuel Element Micro Reactor (FEMR), with 308 square UO2 fuel rods, each one containing inside a heat pipe. We selected Mercury as the working fluid for the heat pipes and operate the microreactor at average temperature around 900 K or 637 °C. Heat pipes introduce empty regions into the core that increase neutron leakage and severely reduce core reactivity. Square fuel lattices allow greater fuel volume fractions and favor increasing core reactivity. The adoption of a 20 cm BeO reflector and Zircaloy as fuel cladding further increases core reactivity. The FEMR core thermal power is 2.3 MW, the power density distribution is rather flat with peaks occurring at the core-reflector interface and the peak fuel temperature is 1160 K. The reactor has a negative temperature isothermal coefficient of reactivity. The reactivity control system with 8 rotational drums and a central cruciform absorber rod meets the criteria of stuck rod and diversity of engineering principles. The average fuel discharge burnup is 8.96 MWd/kgU and the fuel cycle length without refueling is 8.7 years. The ratio between thermal power and total Uranium mass at beginning of life is 2.46 kW/kgU.