Krko NPP

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Krko NPP
Operational and Safety Status of the Krko NPP
(1991 - 2007)
2
Topics

• General Plant Data
• Plant Status
• Electricity Production
• Nuclear Safety
• Fuel Management
• Protection of Environment
• Organization and Human Resources
• Continuous Plant Modernization
• Performance Indicators

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General Plant Data
4
General Plant Data
5
General Plant Data

• Westinghouse 2 loop PWR , turn-key contract
• Investment of two governments, utilities
• Gilbert architect engineer
• Plant history
• construction start in 1975
• September 1981 first criticality
• Januar 1983 commercial operation

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General Plant Data

• Power

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Plant Status

• Bilateral Agreement
• Agreement between the Government of the Republic
  of Slovenia and the Government of the Republic of
  Croatia on the Regulation of the Status and other
  Legal Relationships relating to Investments in
  the Krko Nucelar Power Plant, its Use and
  Decommissioning (valid since march 11th 2003)
  determines
• - ownership and capital,
• - company management,
• - the price and production costs,
• - employment and training,
• - contractors,
• - decomission financing,
• - investments protection and other.

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Plant Status
Plant Management Function
Nuclear Safety Oversight
Bilateral committee 4 (SLO) 4 (CRO)
Administration for Nuclear Safety (URSJV)
The Ministry of the Environment and Spatial
Planning
GEN-Energija 50
HEP Electric 50
Krko Safety Committee KSC
EU-WENRA IAEA WANO
Assembly 1 1
NEK d.o.o. Management Board 1 1
Supervisory Board 3 3
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Electricity SupplyProduction in Slovenia in 2007
and in Croatia in 2007
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Electricity ConsumptionConsumption in Slovenia
in 2006 and in Croatia in 2004
Consumption
Consumption
2007
2006
2007
2006
Increase 2,56 in Croatia
Increase 1,1 in Slovenia
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Electricity SupplyNet Electric Energy Production
Since Start of Commercial Operation of Krko NPP
Goal NEK for 2008gt5,89 TWh
By continously modernizing the plant from 2000 to
2007 its capacity has been increased equivalent
to 5 hydro-electric plants on Lower Sava ( 140
Gwh / plant )
Cumulative 116,41 TWh
Cumulative SLO 2007 13,3 TWh
Net import SLO 2,08 TWh
TWh
Year
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Nuclear SafetyScope of NPP Krko PSA Project
IPE Level 1
Assessment of core-melt frequency on the basis of
analyses of sequences of internal events
resulting from plant design configuration
Completed 1994
NPP Krko PSA Project
Assessment of radionuclide releases from the
reactor core into the environment made on the
basis of analyses of physical and chemical
phenomena of accidents and containment response
IPE Level 2
Completed 1995
IPEEE External Events
Analysis of the risk resulting from external
events (earthquakes, floods, transport accidents)
Completed 1996
Completed Ph. 11994 Ph. 21999
Analyses of shut-down risks resulting from
different conditions of the systems significant
for shut-down and from typical abnormal events
PSA for SDM
Model of decision-making about safety issues and
measures taken with respect to the set objectives
and requirements based on risk assessment
Living PSA
In use
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Nuclear Safety Comparison of contributors to CDF
CDF /reactor year
5,5
5,6
time
42,5
42,3
9,8
9,8
7,2
26,2
25,9
14,8
44,2
29,3
2,1
2,1
3,5
10,9
23,7
24,1
32,7
37,8
CDF2,3E-04
CDF2,2E-04
CDF1,28E-04
CDF8,65E-05
CDF Core Damage Frequendy IEInitiating Event
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Nuclear SafetyPSA risk assessment applications
of Krko NPP

• On-line maintenance activities and system
  configuration
• Plant outage activities and system configuration
  (Paragon)
• Plant modifications assessment
• Periodic plant safety review
• Risk Importance Assessments
• Support to various NEK programs (MOV, AOV,
  Maintenance Rule)

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Nuclear SafetyPSA risk assessment applications
of Krko NPP

• On-line maintenance activities and system
  configuration (example)

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Nuclear SafetyPSA risk assessment applications
of Krko NPP

• Plant outage activities and system configuration
  (Paragon example)

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Nuclear SafetyNPP Krko seismic design bases

• Long term investigation (domestic and
  international experts involved - starting 1964
  intensive from 1971 to 1975 - Geophysical,
  geomechanical, hydro-geological and engineering
  seismological investigations)
• Suggested SSE - 0.22g, at the end conservatively
  adopted SSE 0.3 g, OBE 0.15 g
• Free field response spectrum according to RG 1.60
• Soil structure interaction analysis - SAP IV (6
  blocks, soil springs and dumping values developed
  by - DAppolonia Consulting Engineers)
• All components and systems qualified based on US
  standards and regulations
• SSE Safe Shutdown Eartquake, OBEOperational
  Bases Earthquake, SAP IVstructural analyses
  program

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Fuel Management General Characteristics

• 12 Month Cycles until 2003
• 15 Month Cycle after outage may, 2003
• 18 Month Cycles after outage sept., 2004
• 121 fuel assemblies
• 16x16 pattern, 366 cm active core height
• 235 fuel rods per fuel assembly containing UO2
  pellets, ZIRLOTM (VANTAGE) clad
• 4.55 do 4.95 w/o enrichment for cycle 23
• 501 EFPD (cycle 23) / 335 EFPD (12M cycle)
• 48 56 feed fuel assemblies (18M cycle) / 32
  36 (12M cycle)
• 32 / 28 days outage R07/R09
• Enthalpy rise hot channel factor (F?H) 1.56

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Protection of EnvironmentRadioactive Waste
Material

• Strategy
• Temporary on-site storage of all radioactive
  waste materials within the existent capacity.
• Spent Nuclear Fuel
• The original spent fuel pool capacity was 828
  positions.
• Spent fuel pool was reracked in year 2003 by
  borated stainless steel racks and the capacity
  expanded to 1694 positions (end of life time
  operation -2023).
• Low - level and Intermediate - level Radioactive
  Waste
• Existent on-site storage was designed for 5 years
  of operation.
• By the end of 2007 2299,7 m3 of radioactive
  waste was generated.
• Volume reductions were achieved by modern waste
  processing (supercompaction, burning of waste,
  other).
• Decontamination building was put into operation
  in 2000 to store the replaced primary components
  (SGs, others).
• Low and Intermediate Radioactive Waste Storage
  limitations are critical (2010).

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Protection of EnvironmentRadiation Burden of the
Environment

• All monitored and quantitatively evaluated
  radiation burdens in the environment due to
  emissions from the Krko NPP have been below
  regulatory limits
• Estimated dose burdens received by members of
  critical population group in the year 2007
  amounted to the effective dose smaller than 2
  µSv/year
• Contribution of Krko NPP represents less than 1
  of annual dose received from natural and
  artificial sources

µSv/year
2500
1500
63
2
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Organization and Human Resources Internal
Organizational Structure
KSC (Krko Safety Committee)
President and Member of Management Board
KRVVO (Committee for Rad. Safety and Env.
Protection)
ADVISORS
QA Committee
Quality and
Generel
Purchasing
Financial Director
Engineering Director
Administration
Nuclear Oversight
Technical Director
Director
Director
Director
Engineering
Local
Production
QC
Support
Purchasing
Manager
Superintendent
Superintendent
Superintendent
International Purchasing Superintendent
QA
Maintenance
Design Changes
Manager
Superintendent
Superintendent
Analyses and
Training
Independent
Industrial Safety
Licensing
Manager
Safety
Superintendent
Superintendent
Engineering
Group Coordinator
Radiation
Security Manager
Nuclear Fuel
Protection
Superintendent
Superintendent
Business Information
System Manager
Process Information
Chemistry
Systems
Superintendent
Superintendent
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Organization and Human Resources Personnel
Turnover

• Turnover rate is stimulated by
  restructuring of organization
• Strengthening vital functions of organization
• Increasing competence and efficiency of personnel
• Reducing total number of employees - outsourcing

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Organization and Human Resources Personnel
Holding SRO and RO License

• License validity is 1 - 5 years
• 6 shifts, 5 (6) licensees per shift (2 SRO, 2
  (3) RO, 1 STA)
• 19 licensed engineers (SRO) are in the advisory
  function of shift engineer (STA)

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Electricity CostsKrko Generation Cost 2007

• Nuclear fuel 14
• Operation and maintenance 30
• (materials, services, goods)
• Labour costs 21
• (salaries and wages, social security)
• Nuclear insurance 1
• Depreciation 23
• Interests on bank loans 2
• (original investment, working capital)
• Taxes 6
• Others 3
• 100

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Business Results Cost structure comparison
2006/2007
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Continuous plant modernizationInvestments - Long
Term Investment Plan

• Long Term Investment Plan based on
• strategic internal goals for safe and reliable
• plant operation
• Slovenian Regulatory requirements
• Requirements of International institutions based
• original technology provider (USA NRC, EPRI,
  ASME,..)
• Main Equipment Suppliers recommendations
  (WOG,..)
• International nuclear industry experience (INPO,
• WANO,...)
• NEK internal operating experience programs
• Maintenance rule program

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Continuous plant modernizationInvestments - Long
Term Investment Plan

• Boundaries of long term plan
• Planning period of five years
• Yearly planning in the average amount of
• 20 mio EUR
• Consideration of the global impact on
• the price for kWh
• NEK and Supporting industry human
• resources availability

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Continuous plant modernizationMajor investment
projects

• Already performed
• Steam generator replacement
• Full Scope Simulator NEK
• Low Pressure turbine replacement
• Main transformer replacement
• Spent Fuel Pit Re-racking
• Process Computer Information system
• RCP motor replacement
• MSAR and FWCY heaters replacement

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Continuous plant modernizationMajor investment
projects

• Planned
• Main generator stator replacement
• Chiller units replacement
• Digital Electro Hydraulic Turbine control system
  replacement
• Reactor vessel head replacement
• Emergency AC power system enhancement
• Cooling Towers extension

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Performance Indicators
Unit Capability Factor
NPP Krko goal 2008?91 INPO goal 2010 92
Unplanned Capability Loss Factor
NPP Krko goal 2008 ?1 INPO goal 2005 2
after 2005 no new goals have been set by INPO
regarding this factor
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