introduction to gas fast reactors (gfr) branislav...
TRANSCRIPT
Introduction
to Gas Fast Reactors
(GFR)
Branislav Hatala
GFR Reference concept
The GFR system
is a high-temperature helium-cooled
fast-spectrum reactor with a closed fuel cycle.
The reference design for GFR is 2 400 MWth
The high outlet temperature of the helium coolant
makes it possible to deliver electricity, hydrogen,
or process heat with high conversion efficiency.
As a one of fast reactor would produce heat about 850°C,
which will be able to chemically produce hydrogen
GFR demonstrator ALLEGRO
3
Thermal power 2 400 MW The produced heat will be converted into electricity in the indirect cycle with three gas turbines and one steam turbine
3 x primary loops
3 x secondary loops + 3 x gas turbines (coolant mixture He-N2)
1 x tertiary loop with steam turbine
- Efficiency (~ 45%) ,
Overview of GFR Technology
4
The main parameters of the GFR system
100
Gas-cooled Fast Reactor
ALLEGRO Project
Technology demonstration as a first gas-cooled fast reactor
ALLEGRO
GFR 2400
6
• Sodium cooled fast reactors are the shortest route to fast reactors deployment, but the sodium coolant has some undesirable features:
- Chemical incompatibility with air and water
- Liquid metal reactors have a strong positive void coefficient of reactivity
- Avoiding sodium boiling places a restriction on achievable core outlet temperature.
• Gas cooled fast reactors do not suffer from any of the above:
- chemically inert, - very stable nucleus, - void coefficient is small (but still positive), - single phase coolant eliminates boiling - optically transparent.
• But …
- Gaseous coolants have little thermal inertia => rapid heat-up of the core following loss of forced cooling;
Gas-Cooled Fast Reactor System Why have gas cooled fast reactors ?
7
The technology base for the GFR includes a number of thermal spectrum gas reactor plants, as well as a few fast-spectrum gas-cooled reactor designs.
Ongoing demonstrations include the HTTR in Japan, which reached full power (30 MWt) using fuel compacts and the HTR-10 in China, using pebble fuel.
The GFR may benefit from development of these technologies, as well as development of innovative fuel and very-high-temperature materials for the VHTR.
Technology Base for the GFR
8
Technology Base for the GFR
9
Institute of Nuclear and New Energy Technology, Tsinghua University
HTR-10 (10-MW High Temperature Reactor)
10
O-Arai Research & Development Center, Japan Atomic Energy Agency
HTTR (High Temperature Test Reactor)
11
The test reactor
The reactor - operated since 1998 - thermal output of 30 MWt - gas outlet temperature of 850 - 950 °C. - Primary Coolant: Helium - Fuel: prismatic TRISO fuel
The Japan Atomic Energy Research institute (JAERI) has been building HTTR to develop and upgrade high temperature gas-cooled reactor technology and conduct research on high temperature engineering.
HTTR High Temperature Test Reactor (Japan)
12
HTGR fuel is ceramic-coated and graphite is used as structural material in its reactor core, thus there should be no accidental reactor meltdown.
The heat storage capacity of the core is huge, which minimizes temperature increases even under conditions of abnormal output.
If an accident should occur, core heat can be removed by natural release from the outer surface of the pressure vessel without the aid of the emergency cooling system.
HTTR High Temperature Test Reactor (Japan)
13
The purpose for HTR-10 was to demonstrate electric power generation.
The reactor - operated since 2000 - thermal output of 10 MWt - gas outlet temperature of 700°C. - Primary Coolant: Helium - Fuel: Pebble bed
HTR-10 provides both electric power to the grid and
district heating to the INET campus.
After long and continuous operation, the entire system and main components were checked.
The results show that all detected data are below safety values and all subsystems and main components, are under correct working conditions.
10-MW High Temperature Reactor (China)
14
HTR-10 reactor pressure vessel and steam generator pressure vessel layout
15
Designed by Tsinghua University, China is being built as two 250 MWth nuclear reactors connected to a single turbine.
Based on the technology and experiences of the HTR-10
The reactor
- under construction (first concrete December 2012)) - thermal output of 500 MWt ( 195 MWe) - gas outlet temperature of 750°C. - Primary Coolant: Helium - Fuel: coated particles in cylindrical bed
364 million euro
Construction is scheduled to take 50 months, 18 months for building, 18 months for installation 14 months for pre‐commissioning.
.
HTR-PM (China) High Temperature Gas-Cooled
Reactor-Pebble bed Module
16
.
HTR-PM High Temperature Gas-Cooled
Reactor-Pebble bed Module
17
The HTR-PM project in China will adopt pebble HTR fuel, 6 cm diameter spheres, in which on the order of 10,000 TRISO coated UO2 particles are embedded in a graphite matrix.
China has taken over the German technology for fuel fabrication, and has built its own HTR pebble fuel manufacturing lines.
The “safety” requirement means the HTR-PM will comply with the inherent safety principles, which must remove the decay heat passively from the core under any designed accident condition, and keep the maximum fuel temperature below 1600°C so as to contain nearly all fission products inside the SiC layer of TRISO coated fuel.
Therefore it eliminates the possibility of core melt and large release of radioactive into environment.
HTR-PM
18
Technology Base for the GFR
19
Gas Cooled Fast Reactors
The GFR base design is a fast reactor, but in other ways similar to a high temperature gas-cooled reactor.
It differs from the HTGR design in that the core has a higher fissile fuel content and of course there is no neutron moderator.
Due to the higher fissile fuel content, the design has a higher power density than the HTGR.
The GFR Reactor technologies are common with HTR
20
VUJE, a.s.
Okružná 5
918 64 Trnava
Slovak Republic
www.vuje.sk
VUJE, a. s. Okružná 5, 918 64 Trnava
Thank you
for your attention