Tritium Fuel Cycle Safety W Kirk Hollis 1, Craig MV Taylor 1, Scott Willms 2 1 Los Alamos National Laboratory, 2 ITER IAEA Workshop on Fusion Energy June 14 th, 2018 Slide 1
Overview What is a Tritium Plant? Examples of Designs (Fusion Reactors) Details of some major components Tritium Safety Tritium gas confinement HAZOP Process Slide 2
Overview of tritium processing for fusion energy science at LANL Historical Tritium Station Test Assembly (1976-late 1990 s) To serve as a flexible, full-scale pilot plant for the fusion fuel cycle testing: - Components - Integrated operation - Environmental and personnel protective systems With interest in: - Performance, Reliability, Response to off-normal conditions. And with particular interest in demonstrating that tritium can be handled safely Directly funded by DOE OS FES Slide 3
TSTA consisted of over 10 interconnected systems dedicated to various purposes Slide 4
Simplified LIFE Fuel Cycle Diagram Slide 5
ITER Fuel Cycle Overview DT loop fuel tokamak with T2 and D2 D2 loop supplies neutral beams with D2 (and some H2) Effluent detritiation oxidizes all hydrogen isotopes to water, recovers tritium from the water and exhausts the detritiated gases. Slide 6
Tritium Fuel Cycle Primary Component Vacuum Pumping Exhaust Processing Isotope Separation Storage and Delivery Fueling ITER Support Components Detritiation Systems Room Air Water detritiation Analytical System Controls Diagnostics Building Tokamak Building Tritium Plant Building Slide 7
Exhaust Processing Function Separate hydrogen isotopes (Q 2 ) from other gas impurities Convert other tritiated gas impurities (e.g. Q 2 O and CQ 4 ) to Q 2 Retain gamma emitters (e.g. 41 Ar) to provide time for radioactive decay CH 4 H 2 O CO Catalyst PMR CO 2, CH 4, H 2 O H 2 Detritiated Retentate Permeate (Product) Palladium Membrane Slide 8
Isotope Separation Function Process exhaust Q 2 into T 2, D 2 and H 2 and return T 2 and D 2 Storage and Fueling Recover T 2 from WDS and return H 2 to WDS Recover T 2 from neutral beam D 2 and HD, and return D 2 to neutral beams ITER Conceptual Design Reichert H., Nobile A. LANL 2014 Slide 9
Storage and Delivery Function Recycle DT for torus fueling Recycle D2 for neutral beams Medium-term storage of D and T Long-term storage of T Load-in/Load-out of T Q 2 assay / inventory Collect 3 He ITER Conceptual Design STACI CT Pre/Post Hydride LANL 2017 Slide 10
Integration of Safety Slide 11
Safety Parameters Confinement of tritium Physical state (g,l,s) Controls for gas have been developed and are accepted (SS, double wall, etc.) Inventory Facility will have a material at risk level (MAR) and defined authorization levels within the facility. Activation products Controls have been developed and are accepted (shielding, decay tanks, ALARA, etc.) but products need to be defined. Slide 12
Tritium Safety Tritium Gas confinement Tritium Gas (layers) Double Wall on process lines GB Building / Room air pressure cascade Detritiation system (DS) Diffusion is negligible in most assessments due to temperature Isolatable volumes Tritiated water Slide 13
Definition HAZOP Process- An analysis technique through which deviations from baseline operations or processes are systematically analyzed to identify potential consequences (hazards) used to define system design criteria and to develop detection and controls to ensure safe system operations. The HAZOP system relies on an interdisciplinary team of experts that examines every part of a process to determine how deviation from design intentions can occur, if these deviation result in a consequence of interest and associated hazard, develop detection and control to minimize the impact and then assess the residual risk of the deviation. The HAZOP process can be viewed as a reverse engineering process to identify design criteria needed to perform an operation safely. Slide 14
Systematic Analysis HAZOP relies on Guide Words and Process Variables to assess potential deviations Guide Word: No, More, Less, As Well As, Part of, Reverse, and Other Than Process Variables: Flow, Pressure, Temperature, Containment*, Shielding*, Magnetism*, Radiation*, etc. * Develop specifically for ITER Slide 15
HAZOP Deviation used at ITER PROCESS VARIABLES Flow Pressure GUIDE WORDS No, Not, None Less, Low, Short More, High, Long Part of No flow Open to surrounding environment Low rate Low integrated flow Low pressure High rate High integrated flow High pressure Missing feed, Condensation or adsorption As Well As Also Additional feed, Evaporation or desorption Other Than Wrong material Reverse Backflow Temperature Low temperature High temperature Phase change Auto-refrigeration Confinement Rapid failure Slow leaks No overpressure relief In-leakage Reaction No reaction Slow reaction Runaway reaction Partial reaction Side reaction Wrong reaction Decomposition Procedure Skipped step Partially-completed step Speed Stopped Too slow Too fast Out of sync Concentration Material not present Low concentration High concentration Extra action(s) (shortcuts) Additional material present Wrong action Disconnect (drive shaft or belt break) Wrong material present Out of order, Opposite Backward Magnetism No field Low field High field Opposite field Radiation No radiation Low levels of radiation High levels of radiation Additional rad type Different rad type Power Long power failure Short power failure Power surge Insufficient power Co-location / Adjacent ops Loss of co-located system Reduction in colocated system Excess from colocated system Access/Egress Cannot access Limited access Entrapment Other systems competing for colocated system Impact on colocated system Slide 16
Controls Hierarchy of Controls Elimination Substitution Engineering Administrative Personal Protective Equipment Slide 17
Detection and Controls affect on Residual Risk Slide 18
Risk Matrix Slide 19
ITER Hazard Analysis Phases Phase 1: High-Level system analysis Overall process (e.g. TEP) is treated as a black box Inputs and Outputs are define HAZOP method is applied Implementation of results into initial design Phase 2: Initial system design System segmented into defined units HAZOP method is applied Implementation of results into design Slide 20
ITER Hazard Analysis Process Phase 3: Failure Analysis Modified system undergoes a failure analysis review (e.g. FMEA) Implementation of results Final design developed Phase 4: Procedural Analysis Operational documentation developed HAZOP analysis applied Implementation of results Slide 21
Summary Overview of what a tritium plant would look like Application of Process Hazard Analysis (PHA) into design Questions Slide 22
Support Slides Slide 23
Conceptual Design for TEP System, ITER Integration of HPL experimental data with TEP modeling / sizing Ar/O2 CO Ar, N2, CO, CO2, He/Ne (O2, Q2, Q2O) System Evac* Q2 / Air-likes Test Blanket Ar(T2) LTEP Air-Like/Water-like Processing (ALP/WLP) HV I Storage Tank #1 H2O PMR 1 0.35 m 2 8 torr Spare PMR 0.35 m 2 Spare PMR 2 0.35 m 2 2 torr PMR 3 0.3 m 2 10-3 torr CR 2 AMSB 2 3 liters To ALP/WLP Ar Decay Vessels H2 (Q2) D2 DT DS ISS1 ISS2 ISS3 HTEP Storage Tank #2 From AMSB 1 and 2 Type 2 Diag Ar/DTO NB CP Ar/DTO Torus CP SRD 2.5 Ar/DTO CO AMSB 3 3 liters *System Evac: ISS (e.g., expansion tanks) SDS Long Term Storage Hot Cells Service Vacuum Fueling ANS WDS Roughing Pump System NBI TEP (including CMSB) DS DTO Hot Cell DTO CO AMSB 4 (External) Figure 4: ITER TEP system conceptual process flow diagram for processing. Slide 24
Tritium Processing Design / Safety LANL Capabilities HPL PMR / Permeator (Diffusers) U-bed tritium storage CH 4 H 2 O CO Catalyst Developing small scale isotope separation Conceptual Design TEP (collaboration with SRS) ITER tritium plant processing and facility safety design LM processes; LIFE, MAGLIFE, Industrial partners PMR CO 2, CH 4, H 2 O PMR Design H 2 Detritiated Retentate Permeate (Product) Palladium Membrane STACI Hydride Test STACI CT Pre/Post Hydride Slide 25
Vacuum / Roughing Torus Vacuum Cyropanel Mechanical Pumping Slide 26