Turbine technology
Efficiency improvement Technology
Feature
Apply high efficiency technologies to get greater generator output with no thermal power change
(1) AFP (Advanced Flow Pattern) Blades & nozzles
Shift the mass flow distribution to more efficient mid-span area
(2) Longer LSB (Last Stage Blade)
High Performance by reducing exhaust loss
(3) Leakage Reduction and Control
Application
○ AFP will be adopted at the appropriate stages in high & low pressure turbines.
○ Outer casing can be reused to reduce radioactive waste.
○ Optimum approach will be proposed after detailed measurement of actual equipment has
been taken.
© 2013 Toshiba Corporation
Toshiba Turbine Technology
Toshiba has substantial manufacturing
experience of turbines since 1927 for
nuclear and thermal power plants in the world.
Total production exceeds 1800 units and total
output is over 150 GW. Toshiba’s business
is not only to deliver equipment but also to
retrofit equipment for the improvement of
performance and the prevention of
deterioration.
1) Advanced Flow Pattern (AFP)
In general, the blade has a high efficiency region in
middle passage. AFP nozzles let the middle
passage flow increase and both ends of the passage
flow reduce as shown in the following figures. As the
efficiency of AFP stages increase, the electrical
output can be increased.
Toshiba technology for turbine replacement
contributes to the improvement of electrical
output without changing reactor thermal
power.
Toshiba will supply high reliability & high
performance turbine to maintain safe and
reliable operation, and reduce the inspection
work in the outage.
Benefit
Conventional stage
High efficiency region
AFP Stage
Nozzle Height →
Toshiba has advanced technology for high
performance. It contributes to increase the
electrical output. Refer to the next section
for details.
2. Improvement in Reliability & Maintainability
Nozzle
(Stationary Blade)
The knowledge contributes to reduction of
the maintenance cost and extension of its
life.
For example, Toshiba adopts flame
hardening LP-T blades. It helps you by
eliminating the work to check & replace
stellite plates on blades.
Advanced Design
- Compound lean nozzle
- Mass Flow Optimization
- Profile optimization
- Straight Blade Design
- No intentional control of
mass flow rate
Bucket
(Rotating Blade)
Conventional AFP
Stage
stage
Nozzle Height →
Conventional Design
The benefits of upgrading to Toshiba
turbines are as follows.
1. Increase of the Electrical Output
Toshiba designs the inner casing of LP
turbine based on past experience to resist
deterioration.
Mass flow →
High Performance technology
Stage loss →
Background
2) Longer LSB (Last Stage Blade)
LSB is the important element for improving the turbine
efficiency. Longer LSB contributes to reduce
the exhaust loss which is major loss in steam turbine.
3) Reduction of Leak Loss around Sealing
There are two features to reduce the leak loss around fins.
a) Increase of the number of fins and adoption of
high-low fins
b) Adoption of the high-low labyrinth packing
Snubber Blades & Fins
3. Reducing Radioactive Waste
Toshiba reuses the existing outer casing
with modifications. It contributes to
reduce the radioactive waste.
Blade
Existing
Nozzle
High and Low Fins for
Low Wetness Stages
Rotor
High and low labyrinth packing
© 2013 Toshiba Corporation