C. Kharoua, Y. Kadi, Thierry Stora, J. Lettry, M. Lindroos (CERN) K. Samec(PSI & CERN) J-C. David, D. Ene(CEA Saclay) L. Tecchioet al. (INFN Legnaro), F. Negoita (NIPNE) European Organization for Nuclear Research, CERN CH-1211 Geneva 23, SWITZERLAND Project supported by the European Commission under the FP6 “Research Infrastructure Action-Structuring the European Research Area” EURISOL-DS Project Contract no RIDS The Risk register file of EURISOL facility

I.The goals of the EURISOL risk register 1.An Important input for the Full Engineering Study 2.How it is constructed 3.The methodology and the file II.Target operation related risks and design specifications 1.Mercury leakage for the Hg converter 2.Fission Target risk : Uranium fire 3.Main risks of the Direct Target station III.The decommissioning and radioactive disposal issue 1.Hg disposal and risk associated 2.A concrete example : the CNGS experiment at CERN Overview

Risk Register I.The goals of the EURISOL risk register It is an Important input for the safety report which is mandatory for the study towards the construction of the EURISOL facility. It will be required to build the specification of the “Full Engineering Study” What is it? The Risk Register serves to identify and rank the risk inherent to the installation, operation, maintenance, dismantling and disposal of each items of the facility and to propose the mitigation methods. How it is constructed? The EURISOL RISK Register is directly derived from the CERN-AB risk register elaborated by P. Bonnal (05/05/2003)

Risk Register The methodology used Object Operation phase 1 Failure type 1 Risk 1AssessmentMitigationAssesmentRisk2 Failure type 2 Risk 3... Operation phase 2 Failure type 3 EURISOL-DS RISK REGISTER EquipmentOperational phase and Risk RP [mSv/h] and intervention Risk assessment before mitigation Mitigation of Risk Risk assessment after mitigation OwnerName and location Acronym - Number Action typedesccription of failureDescription of associated riskDose rate Job duration ProbabilityImpactScoreComments - Needed actionsProbabilityImpactScore The file format

Risk Register The Multi Megawatt target station and its ancillary equipment The MMW target station Converter Safety Hull Mercury Hull Hg loop and services EM pump Heat exchanger PipesInstrumentation Hot-Cell and services Robots... Fission targets Confinement Remote handling of Fission target Robots...

Main risk for the Hg converter EURISOL-DS RISK REGISTER Task 2 EquipmentOperational phase and Risk RP [mSv/h] and intervention Risk assessment before mitigationMitigation of Risk Risk assessment after mitigation Owner Name and location Acronym - Number Action type desccription of failure Description of associated risk Dose rate Job duration Proba bility Impa ct ScoreComments - Needed actions Proba bility Impa ct Score T2CGS target vessel??? Operation Rupture of the vanes Loss of Hg flow, flow blockage and cavitation 224 Instrumentation to control Hg flowrates 212 Explosion by Hg boiling 155Containement of Hg (safety hull)111 Overheating of the window 339 Instrumentation to control Window temperature 313 Partial melting of the window 155Containement of Hg (safety hull)111 Let’s take the example of the loss of flow… what will happen?

Beam axis shifted 5 [mm] Example of a failure: Loss of flow study K. Samec

Time [ 1 / 100 s] Temperature [K] Vapor-pressure curve of liquid mercury For instance, to reach P=130 bar it takes 0.7s Estimation of the Temperature and pressure raise in the Hg vessel without flow Loss of flow study K. Samec

Example of barrier design (mitigation) Converter and connection to the beam pipe Mercury target Mercury Safety vessel

Mercury Safety vessel Mercury target Window Window support Example of barrier design (mitigation) Converter and connection to the beam pipe

Mercury Safety vessel Window Window support Beam line Example of barrier design (mitigation) Converter and connection to the beam pipe

Mercury Safety vessel Window Window support Beam line Example of barrier design (mitigation) Converter and connection to the beam pipe

Mercury Safety vessel Window support Beam line Example of barrier design (mitigation) Converter and connection to the beam pipe

EURISOL-DS RISK REGISTER Task 4 EquipmentOperational phase and Risk RP [mSv/h] and intervention Risk assessment before mitigation Mitigation of Risk Risk assessment after mitigation OwnerName and location Acronym - Number Action typedesccription of failureDescription of associated riskDose rate Job duration ProbabilityImpactScoreComments - Needed actionsProbabilityImpactScore T4 UC target/running RU-T- 06 runningfiring target stop of operation, target is lost, removal of target and replace with a new one, clean the pit region. The pit and beam line are highly contaminated. 1PBq avoid oxygen contamination, redondancy of safety valves. Neutral atmosphere during removal may be foreseen 155 Main risk for the Fission target Luigi Tecchio – Task 4

Major Risks: breaking of target container target firing Consequences : Dissemination of radioactivity in the environment fission fragments/sec per target (~ 3 x 10 4 Ci) 1 st container 2 nd container 1 st container 2 nd container Main risk for the Fission target Luigi Tecchio – Task 4

Final town meeting Pisa – 31 st Mar 2009 Risk register for 100kW target station The main feature of the direct targets is : – Risks associated with frequent target exchange, once every 3weeks on average – Risks associated with beam misteering The consequences might be : – Dispersion of radiological contaminant – Fire EURISOL-DS RISK REGISTER EquipmentOperational phase and Risk RP [mSv/h] and intervention Risk assessment before mitigation Mitigation of Risk Risk assessment after mitigation Owne r Name and location Acronym - Number Action typedesccription of failure Description of associated risk Dose rate Job duration Probabilit y ImpactScore Comments - Needed actions Probabilit y ImpactScore T3Target module target module maintenance/ exchange Bad target exchangecontamination 122 regular maintenance services 0 Thierry Stora – Task 3

Final town meeting Pisa – 31 st Mar 2009 Mitigation of the risks Triple confinement of radiological spills Inert (He) gas filling Integrity of confinment monitored (He leak detection)‏ Beam view Iron shielding (under vacuum)‏ He-filled vessel (2 nd containment)‏ Leak-tight penetrations Thierry Stora – Task 3

Final town meeting Pisa – 31 st Mar 2009 Mitigation /Containment Target pit Ancyllary Area A (Cooling)‏ Ancyllary Area B (Electric)‏ Sliding shield Hot cell enclosure (3 rd cont. )‏ Roof plug p. beam Leak-tight penetrations Irradiation Level Handling Level Surface Level Thierry Stora – Task 3

A schematic layout for liquid Hg-target disposal strategy What are the risks associated??? R. Moormann, Chiriki et al. (FZJ) Chemical stabilization of Hg as an inorganic compound, e.g. HgS, HgSe, HgO, Hg 2 Cl 2, HgCl 2 Disposal of liquid Hg 19

CNGS was a approximately 80-90MCHF project (The primary beam tunnel, the secondary beam including decay tube) Dismantling cost: Removal of material (~5% of the project cost) Elimination of material (~5% of the project cost) Removal and elimination of the ~1km decay tube (~100% to 250% of project cost) Overall cost could exceed 3 times the cost of the building phase! Risk assessment: contamination: dust, debris, etc. remote handling must be foreseen for ALL installed pieces from the beginning radiation to personnel – even little doses can add up to a large sum if workers have to cross hot area many times Dismantling MUST be included in the design The example of CNGS at CERN Ilias EFTHYMIOPOULOS CERN - EN/MEF

Conclusion Difficult exercise… Most probably not complete… But very valuable input for the next study towards the construction of the EURISOL facility

Thank you for your attention…