inter-regional workshop on advanced nuclear reactor ... india inter-regional workshop on advanced...
TRANSCRIPT
U.C.Muktibodh NPCIL, India
Inter-regional workshop on
Advanced Nuclear Reactor Technology for
Near Term Deployment
July 4th – 8th , 2011
IAEA Headquarters,
Vienna, Austria
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL 2
Lecture Outline
Introduction to Indian PHWR designs
Nuclear Steam Supply Systems
Safety Systems and ESFs
Turbine Generator Systems
Electrical, Control & Instrumentation Systems
Safety concepts
Security (Physical protection aspects)
Performance of Indian PHWRs
In light of events at Fukushima
Design certification & near term plans
3
4
Developed 540 Mwe PHWRs
& operating experience
gained; Unit size scaled up
to 700 MWe
Developed Front End &
Back End Technologies of
Complete Fuel Cycle
Established Comprehensive
Indigenous Capabilities for
Designing, Equipment
Manufacturing, Constructing,
Commissioning, O&M of 220
MWe PHWRs
FIRST STAGE
Design for 500 MWe
PFBR developed.
Construction
commenced in 2004
SECOND STAGE
Fast Breeder Test Reactor
(40 MWt ) operational
THIRD STAGE
Experimental reactor with U233 fuel
in operation.
Thorium Bundles in PHWRs.
AHWR-300 MWe being developed in
BARC. Technology Demonstration
for electricity generation from
Thourium. Bridge between the I & III
Stages to be Launched in X plan
Indian Nuclear
Power Programme:
Current Status
Current Status
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
The Indian PHWR
18 PHWR units in operation - installed capacity of 4360
MWe
4 units of 700 MWe under construction.
More PHWRs of 700 MWe capacity planned in other
states of India.
Design of PHWRs in India has evolved over the years to
grow into a robust and a proven model
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Power Reactors in India
S. No.
Site/Station/Project Units Type Status Year of
commercial operation
Rated capacity (MWe)
1 Tarapur Maharashtra Site (TMS) TAPS-1&2 TAPS-3&4
BWR PHWR
Operating Operating
1969 2005, 2006
2 X 160 2 x 540
2 Rawatbhata Rajasthan Site (RRS)
RAPS-1&2 RAPS-3&4 RAPS-5&6 RAPP-7&8
PHWR PHWR PHWR PHWR
Operating Operating Operating Under construction
1973, 1981 2000 2009 2016
100, 200 2 x 220 2 x 220 2 x 700
3 Madras Atomic Power Station MAPS-1&2 PHWR Operating 1984, 1986 2 x 220
4 Narora Atomic Power Station NAPS-1&2 PHWR Operating 1991, 1992 2 x 220
5 Kakrapar Atomic Power Station KAPS-1&2 KAPP-3&4
PHWR PHWR
Operating Under construction
1993, 1995 2015
2 x 220 2 x 700
6 Kaiga Atomic Power Station KGS-1&2 KGS-3 KGS-4
PHWR PHWR PHWR
Operating Operating Operating
2000 2008 2010
2 x 220 220 220
7 Kudankulam Atomic Power Project
KKNPP-1&2 KKNPP-3&4
LWR LWR
Under construction Under construction
2011 2017
2 x 1000 2 x 1000
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Evolution of the Indian PHWR
RAPS-1 – AECL
RAPS-2 – Indigenous efforts
MAPS – Changes due to site conditions
NAPS-1&2 - Major modifications incorporated, design upgraded in
line with the internationally evolving safety standards and to cater to
the seismic environment at the site.
KAPS-1&2, KAIGA-1&2 and RAPS-3&4 saw further improvements
leading to standardisation in design and layout for 220 MWe
PHWRs.
2 units of 220 MWe each were constructed subsequently at KAIGA-
3&4 and RAPP-5&6.
2 units of 540 MWe have been constructed at TAPS-3&4 with
minimum import content.
4 units of 700 MWe are under construction and many more planned.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Evolution of the Indian PHWR
Indian PHWR design has come a long way right from
RAPS to current 700 MWe units.
Enormous amount of construction, operation &
maintenance experience and adoption of state of the art
technology for engineering and analysis has contributed
in development of a proven, robust, safe and reliable
model of the Indian PHWR, which will fulfil the energy
requirements of the country to a large extent.
Indian PHWR is a combination of inherent and
engineered safety features, incorporating defence in
depth through active and/or passive means to cope with
DBA.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Introduction to Indian PHWR design
Horizontal reactor vessel – Calandria
Pressure tube concept (306/392 channels)
Natural Uranium fuelled (Fuel pins; Bundles)
Heavy water cooled and moderated
Calandria surrounded by water enclosed in a
concrete structure – Calandria Vault
On-power refueling
Double containment
Suppression Pool (220 MWe, 540 MWe)
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Pressurised Heavy Water Reactor
11
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data
Description 220 MWe 540 MWe 700 MWe
Reactor Thermal Output 755 MWth 1730 MWth 2166 MWth
Power Plant Output (Gross) 235 MWe 540 MWe 700 MWe
Power Plant Output (Net) 210 MWe 485 MWe 630 MWe
Power Plant Efficiency (Net) 27.8% 28.08 % 29.08 %
Plant design life 40 yrs. 40 yrs. 40 yrs.
Primary Coolant material Heavy Water Heavy Water Heavy Water
Secondary Coolant material Light Water Light Water Light Water
Moderator material Heavy Water Heavy Water Heavy Water
General Plant Data
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data (Contd.)
Description 220 MWe 540 MWe 700 MWe
SAFETY GOALS
Core Damage Frequency 10-5 / Year 10-5 / Year 10-5 / Year
Large Early Release Frequency 10-6 / Year 10-6 / Year 10-6 / Year
Occupational radiation exposure 20 mSv/Yr * 20 mSv/Yr * 20 mSv/Yr *
Operator action time (in minutes) 30 30 30
* : Average in any 5 consecutive years
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data (Contd.)
Description 220 MWe 540 MWe 700 MWe
Steam flow rate nominal
conditions
1330 t/h 3078 t/h 3874 t/h
Steam pressure/temperature 4.03 MPA(a)
250.6 deg C
4.17 MPa(a)
/252.8 oC
4.5 MPA(a)
256.3 deg C
Feed Water flow rate at nominal
conditions
1261.7 t/h 3078 t/h 3874 t/h
Feed Water temperature 171 deg.C 180 deg.C 180 deg.C
Nuclear Steam Supply System
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data (Contd.)
Description 220 MWe 540 MWe 700 MWe
Primary coolant flow rate 13.26x106 kg/h 28.1x106 kg/h 28.9 x106 kg/h
Reactor operating pressure 87 kg/cm2g (nom.) 100 kg/cm2g
(nom.)
100 kg/cm2g
(nom.)
Mean temp. rise across core 44 deg. C 44 deg. C 44 deg. C
Average linear heat rate 28.6 kW/m 40.1 kW/m 50.2 kW/m
Fuel material Natural UO2 Natural UO2 Natural UO2
Fuel clad material Zircaloy - 4 Zircaloy - 4 Zircaloy - 4
Fuel assembly 19 elements 37 elements 37 elements
Average discharge burn up 6700 MWd/T 7500 MWd/T 7050 MWd/T
Reactor Core & Coolant System
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data (Contd.)
Description 220 MWe 540 MWe 700 MWe
Inner diameter of Calandria 5996 mm 7800 mm 7800 mm
Wall thickness 25 mm 32 mm 32 mm
Base material Austenitic SS
304 L
Austenitic
SS 304 L
Austenitic
SS 304 L
No of Coolant channels 306 392 392
Lattice pitch 22.86 sq
lattice
28.6 sq
lattice
28.6 sq
lattice
ID of coolant channel 82.6 mm 103.4 mm 103.4 mm
Core length 5.085 m 5.940 m 5.940 m
Coolant channel material Zr– 2.5% Nb Zr– 2.5% Nb Zr– 2.5% Nb
Reactor Pressure Vessel
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data (Contd.)
Description 220 MWe 540 MWe 700 MWe
Type Mushroom type
with integrated
steam drum and
preheater
Mushroom type
with integrated
steam drum
Mushroom type
with integrated
steam drum
Number of SGs 4 4 4
SG tube material Incoloy 800 Incoloy 800 Incoloy 800
Type of coolant pump Vertical,
Centrifugal,
single stage.
Vertical,
Centrifugal,
single stage.
Vertical,
Centrifugal,
single stage.
Pressurizer volume -- 30 Cub M 45 Cub M
Steam Generator, Coolant pumps & Pressuriser
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data (Contd.)
Description 220 MWe 540 MWe 700 MWe
Double Containment Prestressed ICW,
Reinforced OCW
Prestressed ICW,
Reinforced OCW
Prestressed ICW,
Reinforced OCW
PC dimensions 42.56 m dia
55.35 m ht
49.5 m dia
50.1 m ht
49.5 m dia
53.1 m ht
PC Design pressure 0.27 MPa (a) 0.24 MPa (a) 0.26 MPa(a)
Design leak rate of
Containment System
1 % V / day 1 % V / day 1 % V / day
Containment
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data (Contd.)
Description 220 MWe 540 MWe 700 MWe
Residual Heat
Removal (Active /
Passive systems)
Active- SD cooling
system
Passive – Thermo
syphon through SGs
Active- SD cooling
system
Passive – Thermo
syphon through SGs
Active- SD cooling
system
Passive – Thermo
syphon through SGs
Safety Injection
(Active / Passive
systems)
ECCS ECCS ECCS
Core Cooling Systems
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Summarised Technical Data (Contd.)
Description 220 MWe 540 MWe 700 MWe
Type of Turbine Tandem
compounded,
Horizontal
impulse reaction
type.
Tandem
compounded,
Horizontal
impulse reaction
type.
Tandem
compounded,
Horizontal
impulse reaction
type.
Number of turbine
sections
1 HP + 1 LP 1 HP + 2 LP 1 HP + 3 LP
Generator Direct coupled,
Hydrogen cooled
rotor
Direct coupled,
Hydrogen cooled
rotor
Direct coupled,
Hydrogen cooled
rotor
Turbine & Generator
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Inherent Safety Features of Indian PHWRs
Higher neutron generation time
Low fissile content
Short bundle length limits consequences in case of
single bundle failure.
Passive core cooling feature.
On power detection of failed fuel.
Online fuelling and low excess reactivity in the core.
Moderator as heat sink.
Reactivity Devices located in low pressure
moderator : Rod ejection ruled out
22
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
NSSS – PHT System
PHT System has been designed to ensure adequate
cooling of reactor core under all operational states and
during and following all postulated off normal conditions.
Normal Operation By Primary Coolant Pumps (PCPs)
Loss of power to
PCPs
Initially by pump flywheel inertia and later by
thermo syphoning.
Shut down By shut down cooling pumps and heat
exchangers which are independent of SGs
Loss Of Coolant
Accident (LOCA)
By Emergency Core Cooling System (ECCS)
consisting of high pressure D2O / H2O injection
from accumulators and low pressure long term
recirculation by pumps.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
PHT System features
Different feeder sizes & orificing
Controlled pressure at ROH
Over pressure relief to PHT pressure boundary
Feed & Bleed / Pressuriser
Assist natural circulation – Layout
Small leak handling capability
Online purification & filtration
Accessibility during shutdown
Header level control for maintenance of SGs, PCPs etc.
Variable / constant pressure program for SG pressure
control
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
PHT System – Features (Contd.)
Total elimination of valves in PHT System
General reduction in the number of components has
helped to decongest the layout in the pump room
Better maintenance approachability, less
maintenance and lesser dose uptake
Two loop concept
Minimize the inventory loss
Minimize core positive void coefficient
Minimize the enthalpy release to the containment
under loss of coolant accident
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
PHT System – Features (Contd.)
In 540 MWe PHWR, a pressurizer was introduced
for pressure control, while feed and bleed is
retained for inventory control.
In 700MWe units, interleaving of feeders has
been adopted
Reduction in void coefficient
Minimise the reactor over-power during a LOCA
Passive Decay Heat Removal System (PDHRS)
has been introduced for the first time in 700 MWe
units to ensure removal of decay heat in Station
Blackout condition
STEAM GENERATOR
540 MWe
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reactor Core and Fuel design
Heavy Water moderator and coolant
Natural Uranium Dioxide – Fuel
The reactor is an integral assembly of two end shields
and a Calandria with the latter being submerged in the
water filled vault.
Fuel bundles are contained in 306 / 392 Zr-2.5%Nb
pressure tubes, arranged in a square lattice.
At each end, the pressure tubes are rolled in AISI 403
modified stainless steel end fittings, which penetrate the
end shields and extend into the fuelling machine vaults
so as to facilitate on power fuelling
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Calandria
Calandria is a horizontal vessel containing the coolant
channel assemblies, moderator and internal components
of various shutdown mechanisms and reactivity control
devices.
The Calandria structure is fabricated from Austenitic
stainless steel type 304 L.
The design, fabrication, inspection and testing is in
accordance with ASME Section III NB
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
End Shield
The end shield is a cylindrical box whose ends are closed
by the Calandria side tube sheet (CSTS) and the fueling
side tube sheet FSTS).
The box is pierced by 306 / 392 Stainless Steel Lattice tube
arranged in a square lattice. The box is filled with water and
carbon steel balls in the ration 47:53.
The End shields are designed, fabricated and tested as
class II components according to the ASME section III NC.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Calandria and End Shields
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reactor inside vault
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Fuel Bundle
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
37-element fuel bundle (540 MWe/700 MWe)
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Residual Heat Removal & Auxiliary Cooling
Shut down cooling system.
End shield cooling system.
Calandria Vault Cooling system.
Spent Fuel Storage Bay cooling system.
Active process water system.
Service Water system.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Fuel Handling Systems
Fuel Handling System has seen major evolutions in carriage design,
fuel transfer system and controls in progressive stations.
In RAPS/MAPS, FM head is supported on a mobile type carriage,
which moves on rails.
In the standardised design of 220 MWe PHWR, a seismically qualified
fixed column & moving bridge was introduced, which is better suited
for high intensity seismic events. Transit equipment called Transfer
Magazine was introduced in Fuel transfer system in place of Air Lock
and Transfer Arm used in RAPS / MAPS. This facilitates the parallel
simultaneous operation of refueling by FMs on the reactor and
transferring of irradiated fuel from the Transfer Magazine to the storage
pool through Shuttle Transport Tube .
While earlier fuel handling controls employed hard wired system, for
standard PHWRs, computerized control system has been provided.
This has resulted in flexibility and better man–machine interface.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Fuel Handling Systems (Contd.)
540 MWe PHWR, basic design of FT system is
similar to that in 220 MWe PHWRs. Additional
features :
FM design with rack & pinion based ram assembly.
Separate calibration and maintenance facility to
test various sub-assemblies like ram assembly,
separators, B-ram drive, various process devices and
control equipment was introduced . This is specifically
meant for performance testing after major
maintenance.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Fuel Handling Systems (Contd.)
FH system in 700 MWe PHWRs adopts the features of
220 & 540 MWe PHWRs. Based on operating
experience, Fuel Transfer system is based on a unique
concept of Mobile Transfer Machine, which receives
spent fuel from the Fuelling Machine & discharges it to
the spent fuel bay. Accordingly, shuttle transport system
has been eliminated.
There is a single Spent Fuel Storage Bay (SFSB) in 220
MWe PHWRs, whereas for the later 540 & 700 MWe
units, separate SFSB for each unit has been
incorporated.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
FM BRIDGE & CARRIAGE
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
FM Head
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
MOBILE TRANSFER MACHINE
FT
PORT
SWING TABLE
Z-
FRAME
INDEXER
SUPPORT FRAME
CYLINDER
CABLE DRAG CHAIN
BALL VALVE
NEW FUEL PORT
43
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reactor Shutdown Systems
Concept of two diverse and independent shut down
systems was introduced in standard 220 MWe reactors.
Primary Shutdown System (PSS) using gravity fall of
cadmium absorber elements, and
Secondary Shutdown System (SSS) injecting liquid
poison column in vertical tubes located inside the core.
Each of these systems is independently capable of
terminating all conceivable fast reactivity transients from
any state of the reactor. The reactivity transients
considered include those from a large loss of coolant
accident, which result in the fastest reactivity addition rate
in a PHWR due to coolant voiding in the core.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reactor Shutdown Systems (Contd.)
The design in 220 MWe units has additional system
called Liquid Poison Injection System (LPIS) to
augment the negative reactivity worth to take care of
xenon decay during long term shut down.
For 540 Mwe / 700 MWe PHWRs, each of the two shut
down systems have adequate worth for long-term
shutdown. These systems are :
SDS#1 : Cadmium rods that fall under gravity
SDS#2 : Direct injection of poison in moderator inside
calandria
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Emergency Core Cooling
In earlier versions of Indian PHWRs (RAPS/MAPS), the cold
heavy water available in the moderator system is used for
emergency injection into the PHT system and long term
recirculation for postulated LOCA. Subsequently ECCS for
these plants were upgraded by retrofitting high pressure
injection system.
For standard 220 MWe units, the ECCS was modified to
delink the system from moderator system and it includes
High pressure heavy water injection
Intermediate pressure light water injection
Low pressure long-term recirculation
All actions up to and including the establishment of long-
term recirculation from suppression pool are automatic.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Emergency Core Cooling (Contd.)
In 540 MWe PHWR, the high pressure injection is from light
water accumulators. A simple scheme of injecting light water
into all reactor headers followed by low pressure long term
recirculation has been adopted.
In 700 MWe PHWR, there are two trains of ECCS injection
and long term recirculation
2x100% trains of high pressure light water injection system
followed by
2x100% trains of low pressure long term recirculation system by
ECCS pumps.
The equipment/components of two trains are located diversely to
avoid any common cause failure. Pump suction of each train has
got multiple strainers protected by coarse screen to assure
continued long term recirculation flow from ECCS sump.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reactor Containment Systems
The containment system of Indian PHWRs has seen several
modifications in successive projects.
The first Indian PHWR (RAPS) reactors have a single containment
envelope of reinforced concrete cylindrical section and a pre-
stressed concrete dome. In RAPS, pressure suppression in the
containment is provided by a dousing system where water stored in
a very large tank, at the topmost floor of the containment establishes
a curtain of water in the path of releasing steam during postulated
loss of coolant accident to limit the building pressure.
In MAPS and all standard 220/540 MWe reactors a pressure
suppression system is used where the released steam–air mixture
is led to a large body of water (suppression pool) stored at the
bottom of the containment.
In MAPS, a partial double containment was used with primary
containment of pre-stressed concrete, and secondary of rubble
masonry.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reactor Containment System (Contd.)
For standard 220 MWe/ 540 MWe/ 700 MWe PHWRs,
full double containment design has been adopted with
primary containment of pre stressed concrete and
Secondary containment of Reinforced concrete.
In 700 MWe PHWRs, a containment spray cooling
system is provided for dual functions of fission product
mop up and depressurisation of containment to reduce
ground level releases in place of pool-based vapour
suppression system.
The primary containment for 700 MWe units is lined with
steel for achieving better leak tightness
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL 50
Evolution of Indian PHWR Containments
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Engineered Safety Features
Reactor Building Cooling Systems.
Primary Containment Filtration and pump back
system (for 220 MWe and 540 MWe PHWRs)
Secondary Containment Recirculation and
Purge system.
Primary containment Controlled Discharge
system.
52
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
TG & Auxiliaries
Steam turbines for PHWRs are configured as follows :
One single flow high pressure (HP) turbine and one double flow low
pressure (LP) turbine tandem compounded and coupled to 2-pole
generator for 220 MWe PHWRs.
One single flow high pressure (HP) turbine and two double flow low
pressure (LP) turbine tandem compounded and coupled to 2-pole
generator for 540 MWe PHWRs
One double flow high pressure (HP) turbine and three double flow low
pressure (LP) turbine tandem compounded and coupled to 2-pole
generator for 700 MWe PHWRs
As the steam at the exhaust of HP turbine is around 12% wet, it is routed
through moisture separator and re-heater before it is led to LP turbines.
The TG sets for the latest plants are designed to operate on
continuous basis in the band of 47.5-51.5 Hz as against 48-51
Hz to improve availability of the units considering prevailing
variation in grid frequency.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
TG & Auxiliaries (Contd.)
Integral drain arrangement is provided in the turbine
casing to remove the excess moisture
Redundant turbine over speed protection systems
provided
Non-return valves are provided in almost all extraction
lines to close automatically
The generator is provided with hydrogen cooled rotor,
stator core & overhang and water cooled stator
conductors
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
TURBINE GENERATOR – 220 MWe
56
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
C&I in Indian PHWRs
Control and instrumentation is an area of nuclear reactor design,
which has undergone major changes during past 60 years.
Reactor control and protection system of RAPS-1&2 and MAPS-
1&2 was made using conventional discrete analog circuits.
Control room computer system was another step towards
centralization of acquisition of control room data with improved
human–machine interface. The introduction of digital systems
(computers) did away with the problems of analog circuit design.
For KAPS-1&2, more steps were taken towards utilizing the
flexibility of computer-based systems. The boldest of the steps
was to computerize the alarm and trip contact generation
function. The system was called Programmable Digital
Comparator System.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
C&I in Indian PHWRs (Contd.)
Computer Based Systems were further evolved and used for
standard 220 MWe, 540 MWe and 700 MWe PHWRs for
process and reactor control applications. For one of the
Reactor Protection Systems and other safety systems, hard-
wired logics are retained.
In 700 MWe PHWRs, Computer Based Systems are being
designed in clusters. This will ensure uniform architecture for
systems in a cluster.
Operator interface with menu driven screens for control action
and system information were also introduced.
Upgradation of old projects was started in decade of 1990s
and lot of old systems were re-engineered with computer-
based systems.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reactor Protection Systems
In order to protect the plant against „common mode‟
incidents such as fires that could affect many safety
systems at the same time, the I&C of safety systems are
located in distinct, physically separate rooms / panels in
control building (control equipment room).
Each of the safety systems viz. reactor shutdown
systems, emergency core cooling system, containment
isolation system are provided with a triplicate channel
philosophy with 2 out of 3 coincidence logic. This permits
one channel to be tested without affecting normal plant
operation. It also allows one faulty channel to be put in a
safe state. It facilitates inter-channel comparison among
the signals
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Control Room
The main control rooms (MCR) have conventional control
room design, which has evolved from plant to plant with
incremental improvements based on the plant design and
technology available.
Hybrid control rooms, wherein computer based operator
information displays and parameter selection and settings
facilities have been provided.
The normal operations are mostly carried out from discrete
hardwired controls at the panels.
The operator consoles located in the center of these control
rooms provide facilities for detailed presentation of data in
various formats and also provide capabilities for changing
operational parameters using Visual Display Unit (VDU)
consoles of individual systems.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Control Room (Contd.)
The control panels are organized in a plant system-wise
manner, with systems associated with various
associated functions suitably located nearby for ease of
operations.
Control Room is located in the seismically qualified
control building (CB).
CB location is such that it is not affected from internal
missiles from turbine.
Unitized Control Room concept is followed.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Control Room (Contd.)
The MCR panels are placed behind the OICs so that the
operator can view the indications & annunciations on the
MCR panels from his seat.
The MCR panels and OICs of both the units are arranged in
“L” shape having linear image with the other unit. The use of
computerized systems has reduced the density of
components on Main Control Room panels.
A separate Back up Control Room (BCR) has been provided
for each unit. Essential safety functions can be carried out
from BCR to bring the unit under safe cold shut down state in
case of unavailability of MCR.
BCR has been back-fitted in older units.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Control Room (Contd.)
In 700 MWe, compact computerized Main Control Room
(MCR) is provided.
MCR comprises of sitting console based operations with
computerized operating procedure, advance fault
diagnostics and intelligent alarm system.
Plant over view panels and limited hardwired back up
control panels are provided.
Separate Back up Control Room (BCR) is provided for
each unit.
Essential safety functions can be carried out from BCR
to bring the unit under cold shut down state in case of
unavailability of MCR.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
KGS-2 Control Room
TAPS -4 Control Room
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
KAPP-3&4 MCR
66
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Electrical Systems
Offsite Power System
400 kV and
220 kV switchyards,
400kV and 220kV grids.
Start up power for each reactor unit is derived from 220
kV switchyard through one start-up transformer (SUT)
having two secondary windings. Two main cum transfer
switching is adopted for 220 kV switchyard.
Station Auxiliary Power Supply System (SAPSS)
Normal Power Supplies and
Emergency Power supplies
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Electric Power Supplies
Normal Power Supply
This system has two voltage levels at
6.6 kV, 3 phase supply and
415 V, 3 phase supply.
Emergency Power Supply
Emergency Power Supply System consists of three tier
power supply classes i.e.
Class III,
Class-II and
Class-I power supplies.
These Power Supplies feed all the safety / safety related system
loads of the unit and also some of the non-safety system loads.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Control Power Supplies
Main Control Power Supply (MCPS) system
Class-I 48 VDC MCPS system (220 & 540 MWe)
Class-I 24 VDC / 220 VDC MCPS System (700 MWe)
Class-II 240 VAC MCPS system
Supplementary Control Power Supply (SCPS)
system
Class-I 48 VDC SCPS system (220 & 540 MWe)
Class-I 24 VDC / 220 VDC SCPS System (700 MWe)
Class-II 240 VAC SCPS system
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Operating Modes
Normal operation
Operation within specified operational limits and
conditions.
Hot shutdown state
Shutdown state of the reactor with primary coolant
temperature (inlet to reactor) and pressure close to
normal operating condition and the primary coolant
pumps (PCPs) running is defined as hot shutdown state.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Operating Modes (Contd.)
Cold shutdown state
Reactor maintained sub-critical with specified sub-
criticality margin and temperature of the PHT system at
inlet to the core is less than 550C.
Guaranteed shutdown state(GSS)
A specified shutdown state of the reactor with sufficiently
large reactivity shutdown margin, established by the
addition of liquid poison into the moderator to provide
positive assurance that an inadvertent increase in
reactivity by withdrawal of all other reactivity devices
cannot lead to criticality.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Standard Fuel Cycle
PHWRs use 'Natural' uranium in dioxide form as fuel.
Closed end fuel cycle - based on availability of fissile and
fertile fuel resources in the country.
The spent fuel bundles from PHWRs are reprocessed and the
depleted uranium and plutonium is planned to be used in fast
breeder reactors.
A small quantity of reprocessed depleted uranium is also
recycled in PHWRs.
The Front-End of this cycle like mineral exploration, mining
and processing of ore and fuel fabrication; and back end of
the cycle, which includes fuel reprocessing, re-fabrication and
nuclear waste management are carried out by different units
of Department of Atomic Energy (DAE), Government of India.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Alternative Fuel Options
To achieve fuel burn up beyond 15000 MWd/TeU, fissile
materials like slightly enriched uranium and Mixed Oxide fuel
elements have been studied for use in 220 MWe PHWRs.
Studies showed that burn-up can be increased up to 30000
MWd/ TeU.
Studies on reactor physics characteristics like reactor control,
shut down margin, fuel, systems thermal-hydraulics and
material compatibility have been carried out for each fuel type
before taking up actual loading in the reactor.
Reprocessed depleted uranium dioxide fuel bundles, Slightly
Enriched Uranium Bundles (SEU), MOX bundles and thorium
dioxide bundles were designed, developed and successfully
irradiated in different 220 MWe reactors.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Alternative Fuel Options (Contd.)
Thorium bundles and reprocessed depleted uranium dioxide
bundles were used for flux flattening in the initial core such
that the reactor can be operated at rated full power in the
initial phase.
MOX-7 bundle design evolved is a 19-element cluster, with
inner seven elements having MOX pellets consisting of
plutonium dioxide mixed in natural uranium dioxide and outer
12 elements having only natural uranium dioxide pellets.
75
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Defence in Depth
Multiple barriers to radioactivity release
Prevention – is priority and Mitigation – if
deviations or accidentt happens
To achieve defence in depth - SSCs at first four
levels
Elaborate emergency plans at the fifth level
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Defence in Depth (Contd.)
Prevention Seismic design of SSCs
Consideration of possible flood mechanisms to decide safe
grade elevation
Consideration of internal flood in design
Quality requirements for design, fabrication, plant
construction and operation
Safety Classification of SSCs
Assignment of SSCs at various levels of defence in depth
Environmental qualification
Redundancy and diversity at system and function level
Physical and functional separation between process and
safety systems
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Defence in Depth (Contd.)
Prevention (contd.) Single failure criteria
In service inspection and regular surveillance
Operation within defined limits in technical specifications for operation
Licensing and periodic relicensing of operating personnel
Single point vulnerability assessment
Balanced design, quantification of reliability, absence of cliff edge effects, permissible down time of equipment etc. are overseen by PSA
Adherence to normal operating procedures
Regular and multi tier review by utility and regulators
Operating experience feedback
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Defence in Depth (Contd.)
Mitigation – AOOs and DBAs Control systems and protection systems
Safety systems
Multiple means to achieve three fundamental safety
functions
Passive features and systems
Reliable safety support services
Procedures for off normal and emergency conditions
Rehearsing these procedures on plant simulators
Safety analysis to show compliance to acceptable dose
limits and PSA targets
Regular and multi tier review by utility and regulators
Operating experience feedback
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Defence in Depth (Contd.)
Mitigation – BDBAs and severe accidents
Available plant systems
Severe accident management provisions
Severe accident management guidelines
Hydrogen management
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Defence in Depth (Contd.)
Emergency Plans and Preparedness
Hierarchy of emergency plans (Plant, Site and Offsite)
These plans are regularly rehearsed with a defined
frequency
Participation of local government authorities in
emergency exercises
Participation of nearby population in public awareness
programme and emergency exercises
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Licensing
Identified stages (Siting, Construction, Operation)
As per requirements specified by regulators in
codes and guides
Periodic safety review at every 10 years
Review at the time of renewal of license at every 5
years
Internal review within utility
Multi tier review by regulators
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Licensing Approach - Projects
The regulatory body adopts a multi-tier review process for safety
review and assessment of NPP
First level of review and assessment
Site evaluation Committee (SEC),
Project Design Safety Committee (PDSC)
Civil Engineering Safety Committee (CESC).
These Committees as a body are comprised of experts in various
aspects of NPP safety.
The next level of review is conducted through an Advisory
Committee on Project Safety Review (ACPSR)
Members drawn from the regulatory body, reputed national laboratories
and academic institutions.
Representation from other governmental organizations and ministries.
After considering the recommendations of ACPSR and the first level
committee, the regulatory board decides on the authorization.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Licensing
Safety Review Process for Nuclear Power Projects
APPLICATION FOR
SITE CONSENT
APPLICATION FOR
CONSTRUCTION CONSENT
LEGEND: SEC - SITE EVALUATION COMMITTEE
PDSC - PROJECT DESIGN SAFETY COMMITTEE
ACPSR- ADVISORY COMMITTEE FOR PROJECT
SAFETY REVIEW
Governing Document “Regulation of
Nuclear and Radiation Facilities”
(AERB-SC-G)
• Siting
• Construction
• Commissioning
• First Criticality / Tests
• Power Operation (In stages)
Consenting Stages: REGULATORY
BOARD
NPC-SRC HQ
ACPSR
PDSC SEC
Reg
ula
tory
Bo
dy
Uti
lity
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Licensing Approach - Stations
First tier of safety review is carried out by the „Unit Safety
Committee‟
Representatives from the regulatory body
Representatives from NPP under review and
Experts in various aspects of nuclear technology
drawn from different institutions.
The second-tier of safety review of Indian NPPs is by
Safety Review committee for Operating Plants
(SARCOP), which is Apex body to decide on the matters
of nuclear safety pertaining to NPPs.
The third-tier is the regulatory board, which based on the
recommendations of SARCOP, considers the major
safety issues pertaining to operation of NPPs.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Licensing
Safety Review Process for Operating NPPs
Regulatory Board
EXPERT GROUPS
-REACTOR PHYSICS
-REACTOR CHEMISTRY
-CONTROL & INST.
-ISI
-COOLANT CHANNEL SAFETY
REGULATORY STAFF
-INPUTS
-INTERNAL REVIEW
-CONTINUITY
-CO-ORDINATION
-ENFORCEMENT
-FOLLOW-UP
-INSPECTION
Safety Review
Committee for
Operating Plants
(SARCOP)
Unit Safety
Committee
NPC –SRC HQ
Station Operation Review
Committee (SORC)
Reg
ula
tory
Bo
dy
Uti
lity
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Seismic Design Considerations
The seismic design is incorporated by classifying SSC under three
categories
SSE Category : SSE category incorporates all systems, components,
instruments and structures conforming to safety classes 1, 2 and 3 and
are designed for the maximum seismic ground motion potential at site
(i.e. SSE) obtained through appropriate seismic evaluations based on
regional and local geology, seismology and soil characteristics.
OBE Category : All systems, components, instruments and structures
which are to remain functional for continued operation of the plant
without undue risk fall under OBE category and the design basis is a
lower level seismic ground motion than SSE which may reasonably be
expected during the plant life. Exceeding of OBE level seismic event
requires a shutdown of the plant and carry out detailed inspection of
entire plant prior to startup.
General : Seismic design by relevant Indian standards
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Safety Systems to cope with Severe Accidents
An accident sequence involving loss of coolant with failure
of emergency core cooling can lead to a severe accident
with failure of maintaining moderator and Calandria Vault
water heat sink. Fire water injection into SGs.
Fire water injection into Calandria.
Fire water injection into Calandria Vault.
Fire water injection into End Shields.
Provision for passive/active mixing of containment atmosphere to
limit hydrogen concentration.
Fire water back-up is provided to moderator heat exchangers and
ECCS heat exchangers.
Provision for manual interconnection of Class-III emergency power
supplies between units (700 MWe).
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Safety Assessment
A comprehensive safety analysis by rigorous
deterministic and complementary probabilistic methods
is carried out covering the following plant states
Normal operational modes of plant
Anticipated operational occurrences
Design basis accidents
During combination of events leading to beyond
design basis scenarios including severe accidents
The deterministic safety analysis is available up to the
severe accident and is being utilized in conjunction with
probabilistic safety assessment in preparation of severe
accident management programme
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Emergency Planning
In accordance with different degrees of severity
of the potential consequences, emergency
situations are graded as:
1. Plant emergency
2. Site emergency and
3. Off-site emergency.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Emergency Measures
The emergency measures consist of the following
Notification
Assessment action during Emergency
Corrective actions
Protective measures (countermeasures)
Contamination control measures
Infrastructure for Emergency Response
Plant Control Room
Emergency Control Centre
Communication System
Assessment Facilities
Protective Facilities
92
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Security & Physical Protection
Security systems have under gone several changes based on
changing threat perceptions and the technological
developments.
NPCIL has established the environment to create and foster
characteristics and attitudes in organization and individuals so
that physical protection issues receive attention as warranted
by their significance. A multi pronged approach is in place to
ensure security of the country‟s NPPs, which includes the
following :
Screening/ongoing intelligence about employees
Physical Protection System
National Security Force
Defence coverage
Regulatory Frame work
94
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant Operation
The commencement of operation of a Nuclear Power
Plant (NPP) begins with approach to the first criticality
of the station.
Before the start of commissioning activities, the station
prepares a comprehensive programme for the
commissioning of plant components and submits the
same for review and acceptance of Regulatory body.
The Operation and Maintenance (O&M) department at
the station prepares the Technical specification for
operation in consultation with the plant designers before
the approach to first criticality, based on the inputs from
the design and safety analysis.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant Operation (Contd.)
Once the commissioning activities are completed, the entire
plant is handed over for regular operation and
maintenance, to the O&M department which already exists
at the Site.
To ensure a high degree of quality in operation, all
operation persons who are at or above the position of
Assistant Shift Charge Engineer (ASCE) are qualified
graduate engineers who are trained and licensed as per
the licensing procedures approved by Regulatory body.
All activities including surveillance testing are performed
with approved procedures to minimize errors due to human
factors.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant Operation (Contd.)
The station has a well defined organization chart. The chart clearly defines the lines of responsibility and authority to ensure smooth operation as well as safety during start up, normal and abnormal operations.
Station Director is the Chief of Station O&M management at site. He has the overall responsibility for the safe operation of the plant and in implementing all relevant policies and radiation protection rules and other instructions and procedures laid down by the operating organization for plant management, and the statutory / regulatory requirements.
The performance of operating Indian PHWRs has improved significantly and an overall availability factor of greater than 90% has been achieved.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reliability & Availability Targets
Contributing factors :
Successful and proven technology
Extensive use of vast experience available from
Indian PHWR and similar plants elsewhere
High degree of automation to minimize human error
Functionally and physically independent safety
systems
Basic safety functions carried out by multiple means
Online testing and maintenance of a protection
channel without affecting reactor operation
Use of fire-retardant materials
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reliability & Availability Targets (Contd.)
Contributing factors :
Fuel reliability
Elimination of human error
Extensive training
Earthquake resistant design
Adequate defences have been built in the design against
flooding, externally or internally generated missiles, fire, etc.
Highly reliable safety systems with very low unavailability
targets
Defence in Depth
Periodic testing and inspection of active components in safety
systems - Online
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reliability & Availability Targets (Contd.)
Designed for an average annual availability factor of
greater than 90%, averaged over the life of the plant
Targets for different types of outages are planned
accordingly.
Indian PHWRs are normally designed to have one planned
biennial shut down for about one month duration
The maintenance programme is put in place to ensure that
Safety Status of the Plant is not adversely affected due to
aging, deterioration, degradation or defects of plant structures,
systems or components since commencement of operation
and
their functional reliability is maintained in accordance with the
design assumptions and intent over the operational life span
of the plant
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Reliability & Availability Targets (Contd.)
Preventive maintenance schedule for systems,
structures and components
In Service Inspection (ISI) programme
Performance Review Programme to identify and rectify
gradual degradation, chronic deficiencies, potential
problem areas or causes
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Capacity Factors of Operating Units
102
84.89 89.66
81.1 76.29 74.4
63.04
53.72 49.61
60.8
71.37
0
10
20
30
40
50
60
70
80
90
100
2001-02 2002-03 2003-04 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL 103
Availability Factors of Operating Units
86 90 91
88 89 85 83 82
92 88
0
10
20
30
40
50
60
70
80
90
100
2001-02 2002-03 2003-04 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11*
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL 104
Longest Continuous Reactor Operation
289
590
404 394
346
432
250
371
414 407
486
529
0
100
200
300
400
500
600
700
TAPS-1 TAPS-2 RAPS-3 RAPS-4 MAPS-1 MAPS-2 NAPS-1 NAPS-2 KAPS-1 KAPS-2 KGS-1 KGS-2
Day
s
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL 105
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
2007 2008 2009
Pe
rso
n S
ieve
rt
Collective Dose/Unit in Indian NPPs for Routine O&M activities (Older units)
TAPS-1&2 RAPS-2 MAPS NAPS
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
2007 2008 2009
Pe
rso
n S
ieve
rt
Collective Dose/Unit in Indian NPPs for Routine O&M activities (New units)
KAPS KGS-1&2 RAPS-3&4 TAPS-3&4 KGS-3
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
P -
Sv
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Construction Management
Setting up of nuclear power projects in India in about 5 years has
been demonstrated with the help of developments in construction
technology, mechanization, parallel civil works and equipment
erection, computerized project monitoring and accounting systems
Further reduction of construction time is being aimed at
The design of 700 MWe is being carried out in an Integrated
Engineering Environment using state of art tools like 3D plant
modeling, Prodok etc.
The Plant Design, Construction, Operation and Maintenance
organizations together develop a detailed overall Project Master
Plan prior to the start of construction. This encompasses :
Design
Procurement
Construction
Commissioning activities up to the commercial operation
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Construction Management (Contd.)
All schedules are regularly reviewed and monitored to check for
compliance with the overall project plan and to identify any
deviation requiring corrective action.
The project is monitored using quantitative methods appropriate
to the particular activity. Schedules are maintained using modern
technology (Primavera software, etc.) and methods, and updated
as work progresses to realistically reflect the actual work status
Regular interaction between the construction engineers and the
design engineers as well as interdisciplinary design reviews are
periodically carried out to successfully implement the
constructability requirements at the design stage itself.
Standardized component sizes, types and installation details are
provided to improve productivity and reduce material inventories
111
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant Layout considerations
The main plant layout of Indian PHWRs has been
developed on the basis of twin unit concept.
The principal features of plant layout
Concept of independent operation of each unit. Only
some of the common facilities are shared for reasons
of economy.
The buildings have been grouped according to their
seismic classification in consonance with the
classification of the system/ equipment contained.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant Layout considerations (Contd.)
Mirror images in equipment layout are avoided to the
maximum extent possible for O & M convenience
A separate Control Building has been provided as a
common facility. However, the control room and control
equipment rooms located in this building are provided to
cater for unitized operation.
A separate backup Control Room has been provided for
each unit
Emergency power supply systems such as Diesel
Generators, UPS systems and Batteries are separately
housed in safety related structures, for each unit.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant Layout considerations (Contd.)
Proper access control measures are provided by
means of Central Alarm Station (CAS), physical
protection fencing and manned gates.
The two unit module in the nuclear island has been so
chosen that it is possible to :
Enforce single point entry in the radiation zones.
Follow radiation zoning philosophy without undue
inconvenience to the operating personnel.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant layout – 220 MWe PHWR
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant layout – 540 MWe PHWR
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Plant
Layout
(700 MWe)
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
119
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Fukushima Accident - Implications
In depth review by utility and regulators
Extreme natural events
Loss of on site power sources and supply
Loss of water storage and supply
Safety of spent fuel
More than one unit getting affected
Severe accident management
Issues related to emergency handling
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Fukushima Accident – Implications (Contd.)
Extreme natural events
Confirmation of design basis
Evaluating margins
Strengthening as required (like water proofing,
raising levels, additional shore protection measures)
More than one unit getting affected
Revision of procedures
Training and defining roles and responsibilities
Mitigation provisions to take into account this situation
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Fukushima Accident – Implications (Contd.)
Safety of spent fuel
Evaluating existing capabilities (before fuel is
exposed following loss of cooling)
External water make up provisions
Loss of power and water sources/ supplies
Alternate power sources
Augmenting on site water storage
Arranging water from nearby sources
„Hook up‟ schemes to various systems
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Fukushima Accident – Implications (Contd.)
Severe accident management
Enhancing severe accident management programme
with post Fukushima recommended provisions
Incorporation of severe accident management
guidelines
Hydrogen management
Containment safety
Issues related to emergency handling
Accessibility and communication enhancement
Further improving emergency preparedness
124
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Regulatory review
All 220 MWe and 540 MWe units are operating
successfully.
Conceptual design review of 700 MWe PHWRs
completed and detailed design review is in
progress.
Regulatory consent for construction of KAPP
3&4 obtained and construction is in progress.
Regulatory consent for construction of RAPP
7&8 is expected shortly.
Design, Safety and Operability performances of 220 MWe, 540 MWe
and 700 MWe PHWRs in India - U.C.Muktibodh, NPCIL
Deployment schedule
Sr No.
Project Units Expected criticality /
Remarks
1. Kakrapar Atomic Power Project 2 X 700 MWe KAPP-3: December 2014 KAPP-4: June 2015
2. Rajasthan Atomic Power Project 2 X 700 MWe RAPP-7: December 2015 RAPP-8: June 2016
3. Haryana Atomic Power Project 4 X 700 MWe Approved in principle
4. MP Atomic Power Project 2 X 700 MWe Approved in principle
127