Integrated System Level Simulation and Analysis of DEMO with Apros. Sami Kiviluoto

Transcription

1 Integrated System Level Simulation and Analysis of DEMO with Apros Sami Kiviluoto

2 DEMO modelling project Fortum joined FinnFusion consortium in the fall 2015 EUROfusion WPPMI project (Plant Level System Engineering, Design Integration and Physics Integration) with VTT and Fortum Sergio Ciattaglia (EUROfusion), Sixten Norrman and Pekka Urhonen (VTT) In this presentation: Overview of the project and DEMO Model structure and operating concept of DEMO Modelling / simulation cases (as time allows) 2

3 Long-term goals of the modelling task A second Apros modelling task (after balance of plant simulations) Coupled behavior of: Thermal hydraulics Automation Electrical systems Scope of the model To cover normal operation and small transients Include all necessary systems Aims to provide information for: Analysis and optimization of the process Defining constraints Testing alternative concepts (limited data available) E.g. the control methods presented here 3

4 DEMO plant operational principles Fusion reaction: 1 2 D T 2 4 He n + 17,6 MeV Plasma ~ C Pressure in the vacuum vessel < 10-5 Pa (even 10-7 Pa) Tokamak is the primary design concept. Pulsed operation Two-hour-long pulse and 30-minute dwell time Three circuits Primary heat transfer system: helium or water Intermediate circuit: molten salt (energy storage) Secondary steam cycle 4

5 Tokamak Structure (ITER) Central solenoid Blanket Vacuum vessel Divertor Poloidal field coils Toroidal field coils Cryostat 5

6 DEMO Aims to demonstrate commercial viability and produce electricity to grid by 2050 JET: Major radius 3 m Top power output 16 MW (< 1 s) ITER: Major radius 6,2 m Fusion power 500 MW ( s) DEMO: Major radius 9 m Fusion power > 2000 MW (2 hours) Output to grid several hundreds MW Self-sufficient with tritium 6

7 DEMO operation (plasma pulse) 7

8 DEMO operation (dwell time) 8

9 Fission power plant vs. DEMO With a fission power plant the technology is well understood and proven From modelling point of view design documents, measurements and even operational data are in general well available A fusion power plant requires technology that has not been used before outside experimental facilities The design of the systems is ongoing Challenges of the industrial scale are being worked on (load factor, profitability...) Apros is not yet mature for modelling all parts of a fusion plant Reactor model is not included but it will be possible in the future Certain specific types of components in the pulsed power network Not an issue at the moment for the scope of this work 9

10 Task in 2015 (1) Large electrical consumers: Central solenoid, poloidal field coils, cryogenics Full power operation, dwell time operation and transition between them Dwell time optimization with respect to: Re-establishing the vacuum Recharging the central solenoid Other technological restrictions 10

11 Power flow chart Steady Pulsed DT fusion power 20% α, 80% n option TBA Charged particle power and radiation Neutrons and nuclear reactions in shield & blanket Neutron energy not absorbed by shield and blanket Environment Primary heat option Gross electrical Net electrical Low-grade heat option Heat transport system pump power Recirculating power H&CD systems PF coils and CS TF coils Facilities Tritium plant Vacuum pumps Cryoplant Remainder of plant MW 100 MW? 7,4 MW 52 MW 15 MW 0,5 MW 26 MW 11

12 Steady state electrical network 400 kv --- To external grid 400 kv 6 kv --- Emergency safety relevant and investment protection 0,4 kv

13 Pulsed power electrical network 400 kv --- To external grid 400 kv 66 kv kv

14 External grid Turbine shaft Grid Main bus bars Steady State Electrical Network Pulsed Power Electrical Network 14

15 Power consumption profile of CS and PF Dwell time 15 A. Ferro et al., RFX, DEMO input power profiles,eurofusion report for task PMI T01-D01, December 15th, 2015.

16 Gross and net power with added loads 16

17 Task in 2015 (2) Dwell time optimization with respect to: Re-establishing the vacuum Recharging the central solenoid Other technological restrictions Benefits Higher mass flow Higher power production Less molten salt 30 min 25 min 20 min 15 min unit time of one cycle s mass flow of hot molten salt kg/s minimum molten salt tank capacity 9, , , , kg 17 Pekka Urhonen, VTT

18 Shorter dwell time (net power) 18 Pekka Urhonen, VTT

19 Shorter dwell time (cold tank input temperature) 19 Pekka Urhonen, VTT

20 Feed water control Case C P Case B T Case A F T Base 20 Pekka Urhonen, VTT

21 Feed water control (net power) Base case: Molten salt temperature Case A: Feed water flow Case B: With 2 steam pressures Case C: Temperature before turbine 21 Pekka Urhonen, VTT

22 Feed water control (cold molten salt temperature) Base case: Molten salt temperature Case A: Feed water flow Case B: With 2 steam pressures Case C: Temperature before turbine 22 Pekka Urhonen, VTT

23 Conclusion Two modelling task has been initiated early in the design of DEMO power plant Optimizing the heat transfer systems for electricity production Analyzing the interaction of different systems to design a robust plant Although the base assumption and goals are slightly different there is close cooperation between the tasks to maximize synergy Within the scope of this presentation Electrical systems and large consumers were modelled Effects of reduced dwell time on the process were analyzed Three methods to control feed water flow were studied Power production level vs. process stability in transients 23

24 Year 2016 Including blanket model and updating the model with the most recent information from other work packages and industry Identifying operational transients and evaluate control capability to recover the steady state of the plant avoiding the fast plasma shut down Transient analysis to avoid molten salt solidification Avoiding loss of blanket, divertor and vacuum vessel cooling Setting common targets to the two simulation tasks (e.g. turbine control during dwell time) Much focus is still on keeping the process steady during normal operation 24

25 25 Thank you!