Conceptual design of ASTRID radial shielding sub-assemblies

Abstract

The French 600 MWe Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID) project reached in 2015 the end of its conceptual design phase. The core design studies are being conducted by the CEA with support from AREVA NP and EDF. Innovative design choices for the core have been made to comply with the GEN IV reactor objectives, marking a breakthrough with the former Phénix and SuperPhénix Sodium Fast Reactors. One of the biggest challenges of the last five years was to propose a consistent design for the reflectors and neutron shielding sub-assemblies surrounding the fuel core in order to fulfill ASTRID requirements of minimising the secondary sodium activity level. Heavy iterative studies on both core and sub-assemblies were necessary to propose and evaluate different solutions following a strict value analysis process considering neutron shielding performances, life duration, maturity levels, washing and manufacturing capability, and qualification needs. Evaluated options were reflectors sub-assemblies made of steel or MgO rods, and radial neutron shielding sub-assemblies made of B 4 C or borated steel, with different configurations in the design and in the core layout. This paper presents the iterative engineering studies, conducted by CEA and performed by AREVA NP, concerning the radial shielding sub-assemblies for ASTRID core, from the selection of possible solutions to a final consistent conceptual design.

A hybrid approach for neutronics calculations in the neutron shielding of sodium fast reactors

“…The rate of neutron damage on a full year is far lower than one displacement by atom. This figure is coherent with the conceptual studies for the ASTRID core shielding [18] that indicate that the number of displacements per atom is smaller that 5 DPA over the reactor's lifetime (60 years).…”

Nuclear waste from small modular reactors

“…Since fast-spectrum SMRs—cooled by gas or by molten sodium, lead, or salt—forego a neutron moderator, these designs employ neutron reflectors and shielding to mitigate damage to the reactor vessel caused by fast neutron bombardment ( Table 1 ) ( 30 , 31 ). Although neutron absorption cross-sections are, in general, lower for fast than for thermal neutrons, fast neutron fluxes in sodium-cooled SMRs will exceed 10 15 n/cm 2 -s ( 32 ).…”

VVUQ of a thermal-hydraulic multi-scale tool on unprotected loss of flow accident in SFR reactor

“…The nominal primary flow rate is around 8500 kg/s from which 7900 kg/s goes through the core. The latter is composed of an inner core, an outer core, neutronshielding and internal fuel storage [17,18]. Passive complementary safety devices such as hydraulically suspended absorber rod sub-assemblies (called RBH) are also part of the design [19].…”