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The AHTR for Grid Demands of the Future
by Mmeli Fipaza, Eskom - Nuclear Engineering
The AHTR for Grid Demands of the Future
• Enhanced Nuclear Safety
• Constructability and Modularity
• Flexibility of Utilization
• Scalability of Power
Drivers for Gen IV Reactors
The AHTR for Grid Demands of the Future
• Power to be Available WiFi
• Electricity Grids Smaller and Smart
• C02 Reductions Mandatory
• Provide for Cogeneration Power Plants
• Surrogate for Intermittent Renewable
Futuristic Outlook
The AHTR for Grid Demands of the Future
Challenges of Supply
Between the Poles – Blog http://geospatial.blogs.com/geospatial/2013/11/the-challenge-of-balancing-supply-and-demand-when-
intermittent-sources-exceed-20-of-total-power-dema.html
The AHTR for Grid Demands of the Future
• When the PBMR was defined in the mid 1990s it was based on the German industrially demonstrated technology
• The PBMR approach was to avoid any fundamentally new technologies and to move directly to the “demonstration” reactor which would by essentially a first of class of the commercial design
• One of the key elements of the PBMR work was the confirmation that fuel to the required specification could be built locally at NECSA
• Many lessons were learned from the development of the design of the PBMR. Given the South African fuel performance and the technological advances since the original German work, there is great potential to build on the PBMR technology base to achieve higher safety and economic performance.
PBMR Background
The AHTR for Grid Demands of the Future
Options for Development
The AHTR for Grid Demands of the Future
Design a nuclear reactor for the grid demands of the future:
• Plant should fit various size grids
• Flexible to follow load changes
• Adaptable to various demand side requirements
• Simplified construction and maintenance
• Safe without engineered safety systems
• Economic – maximise efficiency, reduce costs
Options for Development
POWER SOURCE & BASE LOAD
BATTERY (Energy storage )
ENERGY TRANSFER( heat exchangers)
BOTTOM CYCLE(Steam turbine-generator )
CYCLE COOLING(Heat rejection)
GEN 2
GEN 1
MSHT tank
(680 oC )
MSLT tank
(280 oC)
HPC
LPC
T
CORE
1200 oC
Steam Super heater
Steam Generator
Pre-heater1
Deaerator
Co
nd
ense
r
Pre-heater
Feed water make-up tank
HP ST
Dry Cooling Tower (2 MW)
Re-heater
Res
idu
al h
eat
rem
ova
l Hx
& b
low
er
Super heated steam 530 to 600 oC
LP ST
Cooling tower water make-up tank
AHTR100: Process Diagram with Direct He Brayton Cycle, Molten Salt, Energy Storage, Steam Turbine and Dry Cooling Towers
The AHTR for Grid Demands of the Future
Impact of a Molten Salt “Battery”
AHTR Operating Points Analyses
The AHTR for Grid Demands of the Future
Concept Layout
Layout based on the kaXu Solar 01 CSP Plant with 100MWe and 3 hour molten salt storage
AHTR would be a 55MW average, with 120MW and 6-hour MS storage (customer dependent)
18m
Admin Bldg
Rx Bldg
MS Tanks
100m
Turbine BldgAir Cooled Cond.
200m 300m0m
The AHTR for Grid Demands of the Future
Concept Guiding Principles– Combined cycle – use of He turbine to provide plant base-load,
bottoming HX-combination to provide secondary circuit load
following:
• Almost double efficiency
– Heat storage in secondary circuit for plant flexibility:
• Heat storage allows nominal 66% load following without
change in reactor power. Plant maintains full power output on
average – ideal for base and peak supply). Can be expanded.
• Modular for adapting to different grid demands
The AHTR for Grid Demands of the Future
Concept Guiding Principles
Achieved through:
– Use of pre-stressed concrete pressure vessel at proven at 9MPa
– He up flow allows deep burn-up with once-through fuel cycle
– Modular power conversion unit, allows 5 day maintenance outage
– Online refueling – no refueling outage.
– Increase efficiency, reduce capital costs.
– Ideally suited for heat applications – Desalination, Hydrogen
production, supports reducing carbon emissions in the fossil
fuel industry.
The AHTR for Grid Demands of the Future
Focus of the AHTR Work Since Inception (09/2016)
2016 focused on design concept:
1. System modelling
2. Physical design
3. Fuel Characterisation
4. Pre-stressed Concrete Pressure Vessel
development
5. Licensing Framework
6. Passive Cooling System
7. Cycle Optimisation
2017 will focus on material qualification and developing
design concept:
1. Material selection and qualification
2. Core physics design
3. Power Conversion Unit Design
4. Pressure Vessel Design
5. Control Systems Design
6. Heat pipes, Heat Exchangers and Turbine Design.
7. High Temperature Fuel performance analysis.
8. Manufacturing processes, including 3D printing.
9. Auxiliaries
10. Centre for High Performance Computing to
implement HTR codes
The AHTR for Grid Demands of the Future
END
Thank you !!!!
Questions??