Thermal-hydraulics analyses of ELSY lead fast reactor with open square core option

Among the next generation of nuclear reactors, well-known as Gen-IV, the LFR (Lead Fast Reactor) is one of the most promising advanced reactor able to comply the principles of sustainability, economics, safety and proliferation resistance. The ELSY project (European Lead-cooled SYstem), funded by the 6th European Framework Programme, aims at investigating the technical/economical feasibility of a high power lead fast reactor with waste transmutation capability.Several innovative design solutions have been proposed at system level and some of them regard the core region with open-assemblies that represents the reference option. To support the design phase and the safety assessment of ELSY, the thermal-hydraulic code RELAP5, modified to treat heavy liquid metals, has been taken into account.The paper deals with the development of the ELSY thermal-hydraulic and point kinetic model for RELAP5 focusing the attention at core assembly level to verify that the temperatures at nominal power conditions stay within the safety limits both in Beginning-of-Cycle (BOC) and in End-of-Cycle (EOC) conditions. Moreover, in order to have a first evaluation of the system behavior in accidental conditions, an Unprotected Loss-of-Flow Accident (ULOF) simulation at BOC has been analysed and discussed.

List of acronyms

ADS

Accelerator Driven System

BOC

Beginning-of-Cycle

DEC

Design Extension Condition

EFIT

European Facility for Industrial Transmutation

ELSY

European Lead-cooled SYstem

EOC

End-of-Cycle

FA

Fuel Assembly

FP6

6th Framework Programme

Gen-IV

Generation IV (four)

GESA

Gepulste ElektronenStrahlanlage (Pulsed Electron Beam Facility)

HX

Heat eXchanger

IC

Isolation Condenser

LFR

Lead Fast Reactor

LMFR

Liquid Metal Fast Reactor

PDS-XADS

Preliminary Design Studies on eXperimental ADS

RVACS

Reactor Vessel Air Cooling System

ULOF

Unprotected Loss-of-Flow

W-DHR

Water Decay Heat Removal