KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association Institute for Neutron Physics and Reactor Technology LEADER: WP5 – Safety and Transient Analysis Status of WP5 activities as of May 2013 E. Bubelis, W. Hering (KIT) presented by G. Mueller

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis et. al. – LEADER PCC meeting, Genova LEADER WPs

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis et. al. – LEADER PCC meeting, Genova LEADER WP5 - Tasks Task 5.1 (Monica Frogheri Global safety approach re-assessment (ANSALDO, KIT-G, SCKCEN) Task 5.2 (Evaldas Bubelis Re-evaluation of consequences of representative accident (key transient) initiators within the DBC and DEC for the LFR reference plant (KIT-G, CIRTEN, ENEA, PSI) Task 5.3 (Konstantin Mikityuk Identification of representative DBC and DEC accident initiators of the ETDR (PSI, ANSALDO, CEA, ENEA, KIT-G, SCKCEN) Task 5.4 (Evaldas Bubelis Analyses of representative DBC events of the ETDR (KIT-G, CEA, CIRTEN, ENEA, JRC-IE, KTH, PSI) Task 5.5 (Giacomino Bandini Analyses of representative DEC events of the ETDR (ENEA, KIT-G, JRC-IE, KTH, NRG) Task 5.6 (Angela Cortes Containment and source term assessment for the ETDR (EA, KTH)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis et. al. – LEADER PCC meeting, Genova LEADER WP5 – Time Table & Milestones Milestones M05/D11 (WPL & T5.3, PSI) - Identification of representative DBC and DEC accident initiators for the ETDR (May 2012) M07/D15 (WPL / T5.4, KIT-G) - Analysis of DBC events for the ETDR (March 2013) M10/D22 (WPL & T5.5, ENEA) - Analysis of DEC events for the ETDR (April 2013) - Milestones; - Draft reports ; - Final reports ; - WP5 meetings. WP5 meetings M01 - LFR updated reference configuration – (TEC ) ; M04 - ETDR reference configuration – (TEC ).

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis et. al. – LEADER PCC meeting, Genova LEADER WP5 – Deliverables & Technical documents Deliverables D04 (T5.1, ANSALDO) - Safety approach for LFR plants (February 2011) D08 (T5.2, KIT-G) - Report on the results of analysis of DBC & DEC key transients for the LFR reference plant (October 2012) D11 (T5.3, PSI) - Identification of representative DBC and DEC accident initiators for the ETDR (May 2012) D15 (T5.4, KIT-G) - Report on the results of analysis of DBC events for the ETDR (March 2013) D18 (T5.6, EA) - Report on Containment Assessment for the ETDR (April 2013) D22 (T5.5, ENEA) - Report on the results of analysis of DEC events for the ETDR (April 2013) Technical Documents T68 (T5.2, KIT-G) - Plant data for the safety analysis of the industrial LFR (March 2012) T58 (T5.3, PSI) - Plant data for the safety analysis of the ETDR (May 2012) T64 (T5.6, EA) - Report on Source Term Assessment for the ETDR (March 2013)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis et. al. – LEADER PCC meeting, Genova Issues identified by WP5 that impacted the design (1/2) Safety issue: excessive amount of lead oxides and other impurities in the lead coolant could result in circuit fouling and slugging with reduction of flow cross sections, potentially causing coolant flow blockages in the FAs Design provisions:  Control of coolant parameters and quality,  Control of concentration of dissolved oxygen in the coolant,  Removal of lead oxide and other impurities from coolant (e.g. using hydrogen or coolant filtration),  Purification and control of cover gas,  Sudden and complete flow blockage prevented by the FAs design solution consisting of multiple inlet openings,  Gradual blockage caused by deposition of material can be monitored by detection of each FA outlet temperature increase (possible due to the adopted wrapped Hexagonal FAs). R&D activities:  Detailed design of the purification and control systems for ALFRED are currently under study.

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis et. al. – LEADER PCC meeting, Genova Issues identified by WP5 that impacted the design (2/2) Safety issue: the high melting point (327°C) can pose concerns related to the possibility of lead freezing/solidification. Is this a safety issue or an investment protection issue? Design provisions:  Feed Water Temperature Control (FWTC) to assure a feedwater temperature not lower than 335 ºC,  Design of DHR actuation logic to exclude the simultaneous operation of both DHRs systems,  Auxiliary heating system to ensure the minimum temperature of the lead by transmitting heat from the secondary system during long outages,  Preheating of surfaces having contact with the liquid lead during commissioning of the plant (without fuel assembly). R&D activities:  Dedicated experimental and computational analyses aimed to demonstrate the possibility of lead re-melting severe fuel damage,  Design changes to DHRs are under investigation in the MAXSIMA project in order to make the grace time infinite, avoiding freezing (eliminating the need of operator action),  The commissioning & start up procedures for ALFRED are under investigation.

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis et. al. – LEADER PCC meeting, Genova Other issues for future R&D activities  Structural erosion and corrosion issues, including components coating  Lead chemistry control related issues  SG tube rupture phenomenon experimental investigation  Possible core compaction issues and countermeasures

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis et. al. – LEADER PCC meeting, Genova Conclusion All foreseen work within WP5 of the LEADER project was successfully completed. WP5 activities are finished. WP5 is closed. Compliments: Our compliments to all LEADER project partners for their close cooperation with WP5. Our special compliments to all WP5 partners for their very nice work and excellent collaboration during all WP5 activities.