fukushima: swiss action plan - nucleus · strategy for coping with total sbo mobile am equipment am...
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IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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N. Cordua IAEA Technical Meeting on Evaluation of NPP Design Safety in the Aftermath of the Fukushima Daiichi Accident Vienna, 26-29 August 2013
Fukushima: Swiss Action Plan
Schweizerische Eidgenossenschaft
Confédération suisse
Condederazione Svizzera
Confederaziun svizra
Swiss Federal Nuclear Safety Inspectorate ENSI
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Swiss actions after Fukushima
Immediate measures
Event analyses
Design re-evaluation
Topical inspections
Backfits
Planning
Tracing
Reporting
Feb 2012
Feb 2013
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Immediate measures: Reitnau
External storage
Reitnau
(1. Juni 2011)
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Immediate measures: SFP
External AM-injection for SFP
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Event analysis
Fukushima team published four ENSI-reports
in 2011 about
Causes and consequences of the events
Analyses of the contributory HOF
Lessons Learned and specific checkpoints
radiological consequences
Action Plan
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Key issues 2012 Natural external events
Loss of safety functions
Venting and H2 Management
Emergency preparedness
Safety culture
Operating experience feedback
International activities
Central Emergency Storage Facility Reitnau
Loss of SFP cooling
Total SBO
Seismic and
flooding design
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Loss of SFP cooling
All NPPs
Backfit of alternative level and temperature
instrumentation
External hook-up points
Beznau and Mühleberg NPPs
Backfit of an alternative SFP cooling system
(designed against DBE and DBF)
Hydrogen production in SFPs
Overrated Fukushima issue
Preventive instead of mitigation measures
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Total SBO
Topical inspections (Nov - Dec 2012)
Strategy for coping with total SBO
Mobile AM equipment
AM procedures
Hook-up points
Main inspection findings
Current strategy: adequate
AM procedures: further improvement
Improvements:
○ Personal for mobile equipment
○ Storage and redundancy of mobile equipment
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Seismic and flooding
safety case
Most updated hazard profiles
Loss of offsite power
Affected dams near the plant
Safety case demonstration for 72h without
external help
Earthquake 1E-4/y
Affected SSCs
Dispersion Dose
limit
100 mSv 1 10 100
Frequenz [Hz]
0
0.4
0.8
1.2
Beschle
unig
ung [
g]
NP 1523-hor KKG
NP 1523-x SPI
NP 1523-y SPI
NP 1523-z KKG
NP 1523-z SPI
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Seismic and flooding safety:
conclusions ENSI confirmed that:
analyzed scenarios correct
dose limits observed
Backfits performed
Seismic safety demonstration to be
repeated with final hazard out of the
PEGASOS Refinement Project (PRP)
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Key issues 2013
Natural external events
Increase of safety margins
Hydrogen Management
Severe accident management
Emergency preparedness
EU stress tests’ follow-up
Operating experience feedback
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Increase of safety margins
Analysis of EU-stresstest will be extended
for all shutdown paths
External (earthquake, flooding, etc.) and
internal events (flooding, fire, etc.) with high
probabilistic importance will be reassessed.
International study of safety improvements
Definition of requirements for accident
management equipment (quality, testing,
redundancy, storage etc.)
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Hydrogen Management
Review of robustness and scope of
measuring equipment in connection with
the assessment of the H2 hazard
Updating of analyses regarding the H2
hazard and investigation of the propagation
of hydrogen from the containment into other
nuclear power plant buildings
Review of the measures and procedures in
place for protection against the H2 hazard
Review of the containment venting path in
respect of the H2 hazard.
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Schedule: Fukushima actions
2011 2012 2013 2014 2015 2016 2017 Actions
Reitnau
Flooding
Earthquakes
Extreme weather
Ext. hookup points
SFP-Instrument.
Add. SFP cooling
Diverse UHS
Licensees ENSI
KKM
KKM incl. LTO KKB
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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International actions
EU stress tests (incl. Follow-up)
IAEA IRRS Mission at ENSI’s
(Nov-Dec 2011)
IAEA action plan
IAEA OSART Mission at Mühleberg-KKW
(October 2012)
WENRA
5 new Technical Working Groups
Update of Reference Levels
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Operators & Regulators
National Progress Reports
Operators & Regulators
Final
National Reports
Peers
Country Reports
xxxxxxxxxxxx
Peers
Peer Review
Summary Report
European Commission
Report to the European Council
EU stress tests and follow-up
31
.12
.20
11
31.12.2012
Peers
Additional site visits
xxxx
Regulators
National Action Plan
Peers
Peer Review
Workshop
WENRA Technical Groups 3
1.0
3.2
01
2
30.0
4.2
012
26.04.2013
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Fukushima actions: insights
Nuclear safety is a process of continuous
improvements enshrined in the Swiss law
Safety case for the Swiss NPPs:
State-of-the-art hazards
State-of-the-art det. and prob. analyses
Compliance with regulatory requirements
Margins are available
Several backfits implemented resp. on-going
IAEA Technical Meeting
26-29 August 2013 – N. Cordua (ENSI)
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Thank you for listening!
Any questions