Transcript CABABILITY OF APROS IN THE ANALYSES OF DIESEL …

CABABILITY OF APROS IN THE ANALYSES OF
DIESEL LOADING SEQUENCES
E. Raiko, H.Kontio, K.Porkholm, presented by A. Ahonen
Fortum Nuclear Services Ltd, Espoo, Finland
Generation
Aino Ahonen
31.5.2007
1
Contents of the presentation
• Loviisa NPP
• APROS simulation software
• Analysis of diesel loading sequences
Generation
Aino Ahonen
31.5.2007
2
Loviisa NPP
• Two VVER 440-type
pressurised-water
reactors. Commissioned
in 1977 and 1980
• After power upgrade the
total electric power of the
plant is now 1020 MW
• Load factors 88.6% and
93.3% in 2006
• Modernization and upgrading project finalised in year 2000
• Operation licensing extension project in years 2005-2007
• I&C renewal project in years 2005-2014
Generation
Aino Ahonen
31.5.2007
3
Advanced Process Simulator (APROS)
• The development was initiated 1986 in co-operation by
Fortum Nuclear Services Ltd and VTT Technical Research
Centre of Finland
• The thermal hydraulic
library contains 3- , 5- and
6-equation models for the
calculation of onedimensional two-phase flow
• The component library
includes an extensive set of
ready-made process
component models for the
simulation of different kind
of processes
Generation
Aino Ahonen
31.5.2007
4
Loviisa Modernization and Power upgrading project
• A modernization and power upgrading program of Loviisa VVER440 reactors was carried out in 1995-1997. As a result of this
program, the power levels of the reactors were upgraded by 9.1
%, from 1375 MWth to 1500 MWth
• The safety analyses included in the FSAR were renewed, and
APROS was the main tool in this analysis work
Generation
Aino Ahonen
31.5.2007
5
Events which were analyzed using APROS code
–
–
–
–
–
–
–
–
–
–
–
–
–
–
LBLOCA
SBLOCA
ATWS
PRISE
reactor coolant pump trips
reactor coolant pump seizure
main feed water pumps trip
feed water line break
loss of on and off-site AC power
overpressure protection analysis
decrease of feed water temperature
Fig. 1. LBLOCA hot rod cladding temperatures (BOC)
inadvertent closure of main steam line isolation valve
inadvertent opening of one steam generator safety valve
uncontrolled withdrawal of a control rod group during power operation
Generation
Aino Ahonen
31.5.2007
6
Loviisa operating license extension project
• The current operating license is
valid until the end of 2007 so an
application for a new operating
license for 20 years was
submitted 1 November 2006
• For the application FSAR
analyses were updated and
again APROS was the main tool
in the analysis work
• Because of improved capabilities
containment simulation the
containment pressure behavior
in LSLBLOCA and MSLB
analyses were calculated now
with APROS as well
Generation
Aino Ahonen
31.5.2007
7
Loviisa I&C Renewal Project
• The Loviisa I&C renewal project was started in 2005 and is
scheduled to be completed in 2014. The I&C system
modernization will cover all automation and control systems of the
power plant
WP 1
16
22
WP 2
31
38
WP 3
22
22
WP 4
31
38
2005
2006
W P : W o rk P a ckag e
2007
2008
U n it 1
U n it 2
Generation
Aino Ahonen
31.5.2007
8
2009
2010
2011
2012
2013
2014
1 6 = O u ta g e tim e in d a ys
A ll M o d e rn iz a tio n s te p s to b e p e r fo rm e d
w ith in th e re g u la rly o u ta g e s
Simulators in the I&C Renewal project
•
•
•
•
Development simulator
Testing simulator
Training simulator
Engineering simulator
Generation
Aino Ahonen
31.5.2007
9
Development simulator
• The HMI of the development simulator
has been implemented on a process
computer platform identical to the
existing Loviisa process computer
system
• The processes and
I&C are simulated
with APROS
application model of
Loviisa
Generation
Aino Ahonen
31.5.2007
10
Testing Simulator
• Based on the Apros model
of the development
simulator
• I&C systems to be
renewed are replaced by
real and virtual I&C
systems including HMI
• New simulation-aided
testing environment has
been developed to support
the testing
Generation
Aino Ahonen
31.5.2007
11
Training Simulator
VIRTUAL
I&C
Connector
APROS
Instructor's station
Generation
Aino Ahonen
31.5.2007
12
Engineering Simulator
• Engineering simulator is
APROS based application
model of Loviisa NPP
different from development
simulator, testing simulator
and training simulator
applications because of the
higher fidelity of the model
versus minor requirement of
real time calculation
Generation
Aino Ahonen
31.5.2007
13
Analyses of diesel loading sequences (1/6)
• In Loviisa NPP there are four emergency diesels to feed safety
related equipment in case of loss of power supply
• In addition one of the diesels can be replaced with connection to a
hydro power plant during maintenance
• In the second phase of Loviisa I&C renewal project changes will
be made to logics and to the total number of the diesel back-up
pumps and fans and also the time delays of the steps of the diesel
loading sequences will be changed
Generation
Aino Ahonen
31.5.2007
14
Analyses of diesel loading sequences (2/6)
• In the loss of the electricity an automation system will connect a
diesel generator in 15 s to the redundant 6 kV voltage grid. After
that the diesel loading sequence will start to reconnect the backup devices to the electricity network, each component group
according to the pre-designed time steps
• If the start command of the device (pump or fan) will come only
after the blackout the starting time of the device can be different
compared to the normal diesel loading sequence step time and
the individual device may start e.g. during the next sequence step
-> so it is possible that the temporary diesel generator load and
current through the transformers can be much higher than the
load and current values in the normal designed sequence step
Generation
Aino Ahonen
31.5.2007
15
Analyses of diesel loading sequences (3/6)
Generation
Aino Ahonen
31.5.2007
16
Analyses of diesel loading sequences (4/6)
• As an example an analysis of a LOCA including loss of on and off
site power is discussed -> aim of the analyses was to find out the
maximum momentary diesel generator load and transformer
current values in different accident situations
• In the simulated accident the high pressure safety injection pump,
low pressure safety injection pump, emergency feed water pump
and secondary side make-up water pump were started at the
unexpected sequence step
• In this case the maximum momentary diesel generator load value
in one redundancy was about 3120 kW and the maximum
momentary current value trough the transformer from 6 kV
network to 400 V network was about 4070 A
Generation
Aino Ahonen
31.5.2007
17
Analyses of diesel loading sequences (5/6)
Generation
Aino Ahonen
31.5.2007
18
Analyses of diesel loading sequences (6/6)
Generation
Aino Ahonen
31.5.2007
19
Conclusions
• APROS has been used extensively in the engineering, safety
analysis and training simulator applications
• The capability of APROS to simulate the whole power plant
including reactor, processes, automation and electrical systems
makes it very suitable for the best-estimate analyses of nuclear
power plants
• APROS is used today as the main safety analysis code at Loviisa
Nuclear Power Plant
• After the Loviisa I&C renewal project APROS will also be the
simulation environment of Loviisa full scope training simulator
Generation
Aino Ahonen
31.5.2007
20