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 October 2011 E. Bubelis, M. Schikorr, W. Hering (KIT-G)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna 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 and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 – Time Table & Milestones Milestones M05/D11 (WPL & T5.3, PSI) - Identification of representative DBC and DEC accident initiators for the ETDR (March 2012) M07/D15 (WPL / T5.4, KIT-G) - Analysis of DBC events for the ETDR (September 2012) M10/D22 (WPL & T5.5, ENEA) - Analysis of DEC events for the ETDR (March 2013) - Milestones; - Draft reports ; - Final reports ; - WP5 meetings. WP5 meetings M01 - LFR updated reference configuration – end 2011 ; M04 - ETDR reference configuration – March WP5 T5.2 needs LFR updated (final design) reference configuration NOW !!! – end 2011 ???

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna 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 (Rev. 0 - May 2011, January 2012 Rev. 1 – September 2011, March 2012) D11 (T5.3, PSI) - Identification of representative DBC and DEC accident initiators for the ETDR (March 2012) D15 (T5.4, KIT-G) - Report on the results of analysis of DBC events for the ETDR (September 2012) D18 (T5.6, EA) - Report on Containment Assessment for the ETDR (Rev. 0 – November 2012, Rev. 1 – March 2013) D22 (T5.5, ENEA) - Report on the results of analysis of DEC events for the ETDR (March 2013) Technical Documents T08 (T5.3, PSI) - Plant data for the safety analysis of the ETDR (March 2012) T14 (T5.6, EA) - Report on Source Term Assessment for the ETDR (Rev. 0 – November 2012, Rev. 1 - March 2013) Foreseen June 2012 ??? Foreseen April 2012 ??? A “must” condition – final updated LFR design ASAP !!!

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 The objective of this task is the re-evaluation of the global safety approach for the LFR reference plant and the development of the safety strategy and approach for the ETDR. The specification of the operational and safety limits, as well as the acceptance criteria for the safety performance in order to facilitate the licensing of the ETDR plant will be developed. Safety system recommendations of the GEN IV Risk and Safety Working Group (RSWG) need to be considered appropriately and differences to other projects as the CP-ESFR for the sodium cooled system should be clearly identified. Task 5.1 Global safety approach re-assessment (ANSALDO, KIT-G, SCKCEN) D04 (T5.1, ANSALDO) - Safety approach for LFR plants (February 2011)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 The main objective of this task is to re-evaluate the consequences of accident (key transient) initiators within the DBC and DEC for the updated LFR reference configuration, as defined by WP3, in order to confirm the safety performance of the plant and to resolve previously identified potential safety issues. Task 5.2 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) D08 (T5.2, KIT-G) - Report on the results of analysis of DBC & DEC key transients for the LFR reference plant (Rev. 0 - May 2011, January 2012 Rev. 1 – September 2011, March 2012) Rev.0 - Foreseen April 2012 ??? Rev.1 - Foreseen June 2012 ??? A “must” condition – final updated LFR design NOW !!! – end 2011 ???

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 Task 5.2 Transient analysis – work load distribution (1)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 Task 5.2 Transient analysis – work load distribution (2)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 Task 5.2 Transient analysis – work load distribution (3)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 Task 5.2 Important: Organizations need at least 6 months to select the strategy of activities in between the partners and with the project leader (qualitative evaluation versus detailed analyses), check whether all information for transient analyses is available, set the needed input decks, test them (benchmark) and do the work. We have 4 organizations (KIT-G, CIRTEN, ENEA, PSI) and 12 MM for the work. WP5 Task 5.2 needs new experimental information from KALLA facility as regards SGTR experiments. Dedicated report “Final report on the SGTR- experiments at the KIT performed 2009/2010” needs to be released by JRC to Task 5.2 ASAP.

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5  The objective of this task is to identify representative accident initiators for Design Basis Conditions (DBC), Design Extension Conditions (DEC) including complex sequences, severe accidents and limiting events. In addition initiating events or accident sequences allocated to the “practically excluded” event category should be identified.  On the basis of the design solution for the ETDR a simplified line-of-defense strategy will be applied to identify accident initiators.  The identified event initiators will be categorized and the more representative for each category will be selected for safety analysis to be carried out in Tasks 5.4 and 5.5.  Impact of specific design solution especially for the heat conversion system will be taken into account appropriately. Task 5.3 Identification of representative DBC and DEC accident initiators of the ETDR (PSI, ANSALDO, CEA, ENEA, KIT-G, SCKCEN)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna The following documents will be used in preparation of D11: D28 : Identification of representative accident initiators (by J. Carlsson and L. Amirabile). ELSY deliverable. March available D02 : Design options for the ETDR (M06) – issued D04 : Safety approach fo LFR plants – issued D07 : Definition of the ETDR core and neutronic characterization (M18) – end of 2011 ??? These documents can be very important for D11 (but will not be available till M24 or M30) : D10 : Conceptual design of the DHR system of the ETDR ( M24 : March 2012) D09 : Secondary cooling concept & feasibility study of heat recovery of the ETDR ( M24 : March 2012) D13 : Plant layout and description of the containment system of the ETDR ( M30 : Sep 2012) Task 5.3: Data to be used K. Mikityuk

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna Task 5.3: Proposed structure of D11 and work distribution 1.Introduction ( PSI, KIT) 2.Brief description of the “frozen” ALFRED design ( PSI, KIT) -- Core design -- Heat conversion system -- Containment 3.Revision and possible extension of the master logic diagrams (MLD) of main challenges for the three physical barriers (based on OPT performed in D04) ( ANN, SCKCEN, ENEA; reviewers KIT, CEA, PSI) -- Fuel cladding -- Reactor cooling system boundary -- Containment 4.List of initiating events categorized according to their probability (based on the list provided in D04, but with more detailed specifications). ( ENEA, ANN, SCKCEN; reviewers KIT, CEA, PSI) 5.Final list of transients (DBC & DEC) to be analyzed by Tasks 5.4 and 5.5 ( SCKCEN, ANN, ENEA; reviewers KIT, CEA, PSI) 6.Conclusions ( PSI, KIT) K. Mikityuk End Dec 2011 End Feb 2012

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 The main objective of this task is to evaluate the consequences of representative accident initiators within the DBC. Specific attention will be given to the consequence evaluation of partial and/or total blockages in a fuel assembly and to consequences of steam generator tube ruptures (SGTR). An input data set representing the plant in sufficient detail will be established on the basis of a specific deliverable developed in strict collaboration with WP3. Several suitable computer codes (i.e. SIM-LFR, SAS-LFR, RELAP, TRACE, CFX) available among the partners will be used to analyze transients behavior within design basis conditions (DBC) including those requiring 3-dimensional neutron kinetics. The DBC accidents to be analyzed will be specified within Task 5.3. Consequences of SGTR will be analyzed with special attention. The SGTR could potentially lead to a rapid pressurization and shock waves in the heat exchanger (HX). By analyzing a section of a full bundle HX it will be possible to evaluate the generated pressure waves. The other important aspect is to investigate whether the steam bubble or bubbles can be dragged downwards towards the core inlet region. Task 5.4 Analyses of representative DBC events of the ETDR (KIT-G, CEA, CIRTEN, ENEA, JRC-IE, KTH, PSI) D15 (T5.4, KIT-G) - Report on the results of analysis of DBC events for the ETDR (Sept 2012)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 The main objective of this task is to evaluate the impact of the core and plant design features on the Design Extended Conditions (DEC) including complex sequences. Several computer codes (i.e. SIM-LFR, SAS-LFR, RELAP, TRACE, CFX, SIMMER, SPECTRA) principally available among the partners will be applied to evaluate consequences of selected un-protected accidents scenarios such as Loss-of-Flow, Loss-of- Heat Sink, and Reactivity initiated accidents. Additionally consequences of SGTR events allocated to DEC are to be evaluated within this Task. However, priority will be given to those representative accident initiators identified and selected in Task 5.3. It will be analyzed qualitatively what specific problems might occur when part of the core materials should become mobile and become relocated within the reactor vessel. Task 5.5 Analyses of representative DEC events of the ETDR (ENEA, KIT-G, JRC-IE, KTH, NRG) D22 (T5.5, ENEA) - Report on the results of analysis of DEC events for the ETDR (March 2013)

Institute for Neutron Physics and Reactor Technology (INR) E. Bubelis and W. Hering – LEADER PCC meeting, Bologna LEADER WP5 The objective of this task is to provide a scoping assessment of the Source Term that may be available for release to the environment through containment leakage at some assumed rate. The Source Term assessment would include thermodynamic calculations to assess what fission products and which Polonium compounds may be formed. This task will also provide an assessment of the adequacy of the containment systems. The activity will consider the scenarios in which there may be thermal and pressure loadings of the containment due to the release of secondary coolant and fission product release from the primary system to the containment. Another activity will be that of the transport of airborne radio-nuclides in the containment and their potential release to the environment. Task 5.6 Containment and source term assessment for the ETDR (EA, KTH) T14 (T5.6, EA) - Report on Source Term Assessment for the ETDR (Rev. 0 – November 2012, Rev. 1 - March 2013) D18 (T5.6, EA) - Report on Containment Assessment for the ETDR (Rev. 0 – November 2012, Rev. 1 – March 2013)