Boccaccini, L.V.

Carloni, D.

Dongiovanni, D.

Jin, X.

Pinna, T.

Stieglitz, R.

English

Boccaccini, L. V.

KITopen

KIT – University of the State of Baden-Wuerttemberg andNational Research Center of the Helmholtz Association28th Symposium on Fusion Technology29th Sept. – 3rd October 2014, San Sebastian SpainPriority list of the event sequencesConfinement scheme* Safety risk approachList of Postulated Initiating Event (PIEs) from FFM EA Preliminary safety studies for the DEMO HCPB blanke t conceptX. Jina), D. Carlonia), L.V. Boccaccinia), R. Stieglitza), T. Pinnab), D. Dongiovannib)a) Institute of Neutron Physics and Reactor Technology (INR)P.O. Box 3640  D-76021 Karlsruhe, Germanyb) ENEA, Via Enrico Fermi 45, 00044 Frascati (Roma), ItalyP3.179Proposal of the most severe accidents affecting the  plant safetyPIE DescriptionFB1 Loss of flow in all FW-BK (first wall blanket) cooling channels of one section from total four coolant distribution sections for the outboard or inboard segments (48 or 32) because stop of circulators for CCF (common cause failure)FB2 Reduction of flow in all FW-BK cooling channels of one section of the outboard or inboard segments because stop of circulator in one SG (steam generator) lineFB3 Reduction of flow in cooling channels of one FW-BK module because internal cloggingAOP1 Loss of off-site power <1 hAOP2 Loss of off-site power from 1 h up to 32 hHB1 Loss of heat sink in all FW-BK primary cooling circuits because trip of both HP (high pressure) and LP (low pressure) turbines due to loss of condenser vacuumHB2 Loss of heat sink in one FW-BK cooling trainLBB1 Loss of FW-BK cooling circuit inside breeder blanket box: rupture of a sealing weldLBB2 Loss of FW-BK cooling circuit inside breeder blanket box: leak of a sealing weldLBO1 LOCA Out-VV because large rupture of He manifold feeder inside PHTS vault LBO2 LOCA Out-VV because small rupture of He manifold feeder inside PHTS vaultLBO3 LOCA Out-VV because rupture of tubes in a steam generator (SG)LBV1 Loss of FW-BK cooling circuit integrity inside VV: Rupture of FW-BK moduleLBV2 Loss of FW-BK cooling circuit integrity inside VV: Leak from FW-BK moduleTBO2 Small rupture from PHTS CPS process line inside the PHTS vault (Outside VV), i.e. significant amount of tritium released into buildingN/S Not Safety Relevant Loss of power: AOP2 LOFA inducing in -vessel LOCA: FB1 Ex-vessel LOCA inducing in -vessel LOCA: LBO1, LBO3 Loss of heat sink due to loss of condenser in the S WCS: HB1 In-box LOCA inducing in -vessel LOCA: LBB1Safety relevant sources Energy In operation: enthalpy in structure and coolant, plasma thermal energy, magnetic energy Decay heat after the plasma shutdown Energy from exothermal chemical reactions between materials (e.g. Be-air/steam etc.) Energy release due to postulated H2 explosion (H2 production due to possible Be-steam or W-steam reaction by water cooling) Tritium In the VV (PFC, blanket structure, Li4SiO4, Be, He coolant, He purge gas, armor W of divertor, divertor structural and heat sink materials, water coolant, Tokamak dust, etc.) Out of the VV (PHTSs, TES, tritium plant, hot cells, cryogenic system, etc.) Tritium losses into the environment Tritium decay Activation products in structures, Tokamak dust and coolant (corrosion) Activated structural materials constituting the in-vessel components are made of W alloys, copper alloys and EUROFER Dust aerosol particulate, broken flakes, globules, chunks, and other debris in the VV radio-toxicity due to the high activation of tungsten remove from the VV, if its inventory will approach the safety limit ACPs in the divertor, VV cooling loops and other cooling loops related to auxiliary heating or diagnostics equipment using water as coolant Neutron sputtering products neutron-induced sputtering as mechanism to produce radioactive inventories in the heat transfer system  Station Blackout (SBO)A total loss of all alternating current (AC) power as a result of complete failure of both off-site and on-site AC power sources ⇒ stop of all circulators, pumps and emergency diesel generators.  Bounding accidentNo active cooling, no active safety system operating, and no intervention for a prolonged period are foreseen − the worst consequences of an accident driven by in-plant energies.* The scheme will be updated in the on-going safety program of EUROfusion.Main safety systems VV and its extension (1 st barrier, 1 st confinement) VVPSS/EV (2nd barrier, 1 st confinement)  Cryostat (decay heat remove) FPSS (plasma termination) Emergency cooling (2 nd barrier, 1 st confinement)  Tokamak and Tritium Building (3 rd barrier, 2 nd confinement) HVAC, N-VDS and S-VDS (3rd barrier, 2 nd confinement) Common release point (3 rd barrier, 2 nd confinement) Nitrogen injection / PAR (Passive Autocatalytic Rec ombiner, avoid H 2 explosion) Coil fast discharge system (avoid arc in magnets, a void short in magnets) Emergency power supply (supply emergency safety sys tems) Fire barriers / suppression (prevent propagation of  fire)[W. Gulden]

Preliminary safety studies for the DEMO HCPB blanket concept

https://publikationen.bibliothek.kit.edu/220097174/3816624

Preliminary safety studies for the DEMO HCPB blanket concept

Abstract

Similar works

Full text

Available Versions

KITopen