4th CNS Review Meeting, Vienna, 15 April 2008. 4 th Review Meeting of the Convention on Nuclear Safety SLOVENIA Country Group 6 Vienna, NH Hotel, 1 5 April 200 8. Outline. Nuclear Safety 2005-2008 Legislative arrangements Regulatory supervision Issues from 2005 (Follow-up)
4th CNS Review Meeting, Vienna, 15 April 2008 4th Review Meeting of theConvention on Nuclear Safety SLOVENIA Country Group 6 Vienna, NH Hotel, 15 April 2008
Outline • Nuclear Safety 2005-2008 • Legislative arrangements • Regulatory supervision • Issues from 2005 (Follow-up) • Questions 2008
NPP Krško Nuclear Slovenia TRIGA Mine
Slovenia, the smallest nuclear country We have everything the big country has … … but we have to manage it with less resources!
Highlights/Themes of 2008 Report Nuclear Facilities
Westinghouse PWR 2 loop 700 MWe Commercial operation since 1983 Ownership 50:50 Slovenia-Croatia Highlights/Themes of 2008 Report Krško NPP
Highlights/Themes of 2008 Report Krško NPP: Operation • Without major problems • Last reactor trip in 2005 • 18 month fuel cycle
Highlights/Themes of 2008 Report Krško NPP: Performance Indicators Load Factor
Highlights/Themes of 2008 Report Krško NPP: Performance Indicators Electrical Energy Production
Krško NPP: Performance Indicators Number of Reactor Trips
Highlights/Themes of 2008 Report Krško NPP: Performance Indicators Collective Dose
Highlights/Themes of 2008 Report Krško NPP: Performance Indicators Unavailability of Auxiliary Feedwater
Highlights/Themes of 2008 Report Krško NPP: International Reviews • OSART Follow-up (November 2005) • Overall impression was positive. • Majority of issues fully resolved. • Commitment for improvements, • Priority remains on nuclear safety at all levels, • Effective use of computer technology. • Areas for improvement: • Industrial safety should be improved. • Volume and storage of low level waste. • Enhancing the use and adherence to procedures in the field.
Highlights/Themes of 2008 Report Krško NPP: Issues • Extension to 18-month fuel cycle • Foreseen already in 2000 during SG replacement • New fuel with 1.4X IFBA burnable absorbers • 2004 – first extended cycle was 19 months long • Only few operational problems with fuel leaks • Increase in tritium production • Emergency preparedness exercises: • Annual exercises in the Krško NPP with the participation of the SNSA • Slovenia participated in “CONVEX-3” exercise in May 2005 organized in the Cernavoda NPP
Highlights/Themes of 2008 Report Krško NPP: Finances • Operator must ensure sufficient financial resources throughout the operating lifetime. • Owners of Krško NPP are approving 5 years investment plan • No problems with any delayed payments in recent years.
Highlights/Themes of 2008 Report Krško NPP: Human Resources • Krško NPP staffing • Approaching the period of retirements • Active employment policy • Currently 570staff members • No plans for bigger reductions
Highlights/Themes of 2008 Report Krško NPP: Human Resources • Systematic Approach to Training • Retraining of licensed personnel (typically 4 per year), two-year cycle of requalification training • Full-scope replica simulator: • Abnormal Operating Procedures validation • Unusual events analysed, corrective actions proposed • Validation of some scenarios in the scope of the Periodic Safety Review recommendations in 2006 • Training for subcontractors (General Employee and Radiation Protection)
Highlights/Themes of 2008 Report Krško NPP: Human Resources • Training for specific areas: Refuelling Operations, Maintenance, Engineering, Radiation Protection, Chemistry, Security, Emergency Preparedness • Maintenance training centre • SNSA and TSO training: • two months of initial training on nuclear technology in Ljubljana, • the US NRC Training Center in Chattanooga, USA, • the Krško NPP - classroom training and simulator training, • international courses and workshops
Highlights/Themes of 2008 Report Krško NPP: QA and Safety Culture • QA and ISEG merged • “Quality and Nuclear Oversight Division” responsible for : • Design Modification Control, Procurement documents control, QA review of Plant Procedures, Document Control, Procurement control, Control of special processes, Inspection control, Audits, • Self-assessment program, Safety culture oversight, Human performance oversight, Operating experience oversight, Corrective Action Program • Safety Culture review
Highlights/Themes of 2008 Report Krško NPP: Major modifications • Computer program PAD 4.0 for fuel elements design basis calculation. • Beacon-TSM application as a Power Distribution Monitoring System (PDMS). • Replacement of a traveling screen for the service water pump suction. • Replacement of fire alarm annunciators, pipelines, isolation valves and the hydrant on the fire protection system. • Replacement of the central alarm system. • Old 10 kV distribution grid replaced by a 6.3 kV house grid.
Highlights/Themes of 2008 Report Krško NPP: Major modifications • Replacement of the water pre-treatment and the water treatment system. • Installation of a super compactor, • Installation of a preheating and pressure side venting of heater drain system, • Replacement of two low pressure turbine rotors, stators and bearings with better thermo-hydraulic efficiency (about 3%), • Installation of seismic protection equipment on the polar crane in the reactor containment building. • Chilled Water System Chiller Replacement, • Reactor building recirculation sump strainer replacement, • Replacement of thermal insulation inside the containment.
Highlights/Themes of 2008 Report Krško NPP: Major future modifications • Under construction: A new cooling tower • Announced: Digital Electro-Hydraulic Control System – DEH • In preparation: Installation of the third emergency Diesel Generator DG3
Highlights/Themes of 2008 Report Krško NPP: Problems • Disintegration of an AF flow distributer in SG • Increased AF and IB room temperature • Warming of Ultimate Heat Sink - Sava river
Highlights/Themes of 2008 Report Disintegration of AF flow distributer in SG • Two loose partsfound during outage 2007 in the secondary side of steam generator • Disintegrated AFW flow distributor (vanes, 150x70x20mm) • ~50 U tubes had marks of mechanical damage, 16 U tubes were plugged • AF flow vanes also exhibited cracks also in another steam generator • Both flow distributors replaced
Highlights/Themes of 2008 Report Increased AFW Room Temperature • In summer temperature in turbine drive auxiliary feedwater pump raises above maximum allowed. • Four times between 2002 and 2005 • Special analysis established that equipment can withstand 46°C. • Maximum allowed temperature increased from 40 to 46°C • Issue will be addressed through Aging Program and Maintenance Procedures
Highlights/Themes of 2008 Report Sava River high temperature • River Sava temperature is warmer every summer! • Approaching ultimate heat sink limit temperature! • Actions: • improved Service Water System pumps characteristics in 2002 and 2004 • temporary Justification for Continuous Operation up to 27,4oC • modification of Chilled Water System underway (air cooled) • Remains an open issue
Highlights/Themes of 2008 Report Resolution of sump clogging issue • Slovenia closely followed US NRC GL 2004-02 requirements • Isolation at lower levels and critical points replaced with metal reflecting isolation • Sump screen/strainer replaced – new one with 300+m2 area, 1.6 mm diameter mesh • Procedure for control of materials in containment in place
Highlights/Themes of 2008 Report Krško NPP: Tritium issue • Tritium releases problem after introduction of 18-month fuel cycle. • In 2006 the quarterly release limit of 8 TBq exceeded. • Tritium contributes to annual effective dose <10 nSv. • SNSA increased annual limit from 20 to 45 TBq and halved the limit for other liquid discharges
Highlights/Themes of 2008 Report Krško NPP: Issues from outside • Hydro Plants • Airport
Highlights/Themes of 2008 Report Krško NPP: Issues from outside – Hydro Plants • Chain of HPPs under construction on river Sava up and downstream of NPP • SNSA is setting conditions for these constructions • Reassessment of external flooding hazard to the Krško NPP: • probabilistic assessment of floods – Q(10.000) values higher by 12% • some deficiencies in flood protection dikes identified • probable maximum flood (PMF) analysis according to ANSI/ANS-2.8-1992 underway - PMF values higher for 35-50% • flood analysis for HPPs dam failures according to ANSI/ANS-2.8-1992 is underway • Krško NPP protection against flooding needs to be upgraded • At the same site are planned radwaste repository and a new NPP
Highlights/Themes of 2008 Report Krško NPP: Issues from outside – Airport Cerklje • Airport Cerklje in the vicinity of NPP Krško will be expanded • In- and out-going air traffic will increase • Air exclusion zone (r=1km, h=5000ft) around NPP remains in force • Military facilities at the airport will be refurbished and expanded with civil aviation • A study into possible effects to NPP Krško is underway • Decrease in nuclear safety will not be allowed
Highlights/Themes of 2008 Report The second NPP unit • Planned since July 2006 • Should go on-line 2017 • Project has not started yet • It will most probably be a PWR at the same site • The GEN-energija utility will be the investor
Highlights/Themes of 2008 Report Siting of new NPP
Highlights/Themes of 2008 Report Licenses, legal procedures Facility type “Simplicity” of the process Many players: • Government • Ministry of Environment • Ministry of Economy • SNSA • … NPP Several Laws: • Spatial Planning • Protection of Nature • Construction • Mining • Nuclear Safety
Highlights/Themes of 2008 Report SNSA’s role Siting Construction Trial operation Operation End of operation Decommissioning
Other facilities • TRIGA research reactor • Central Interim RW Storage • Former Uranium Mine • Looking for the LILW Repository • >1000 sources of ionizing radiation
Low and Intermediate Level Repository • Three repository options studied for a site close to the Krško NPP. • Site is not perfect – problem of floods • Underground silos proposed • ~55 m deep and 30 m diameter built from the surface, • Public hearing and acceptance process is underway • Should be finally accepted by the Government. • Possible expansion for Croatian half of waste
Legislative and Regulatory Framework • Act on nuclear safety from 2002 • 22 decrees and regulations • Several older still valid • Intensive involvement in WENRA process • Two regulations will harmonize with WENRA • On nuclear safety design bases, documentation and licensing • On operational nuclear safety • Being discussed, adopted 2008 or 2009.
Slovenian Nuclear Safety Administration SNSA • SNSA - within the Ministry of the Environment and Spatial Planning
SNSA: 46 staff positions. 9 Ph.D. 14 Master of Science 20 Graduated Engineers 3 Technical Staff Annual budget about 2,7 mio EUR Independent in its professional decisions. Licensees may appeal to the Ministry of Environment Drafts regulations or decrees Issues individual legal acts - decisions to the licensees. Independent inspection SNSA ID
SNSA Management System SNSA: • December 2007: ISO 9001:2000 certified
SNSA Management Meeting (daily) SNSA Integrated Assessment System Feeling about the Climate in the NPP BAD Third Party News Inspections OEF Analyses Licensing of Changes Reporting Managementmeetings Rumors NPP Safety Indicators Outages
Highlights/Themes of 2008 Report SNSA System of Safety Indicators
Highlights/Themes of 2008 Report SNSA Risk Based Regulatory Oversight
Highlights/Themes of 2008 Report SNSA Risk Based Regulatory Oversight