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Nuclear powerpost-Fukushima
Dr Selena NgRegional Director, South-East Asia & OceaniaSIEW Electricity Roundtable – Singapore – November 2011
Copyright AREVA 2011 – All rights reservedAny reproduction, alteration, or transmission to any third party of any part of this document or its content is strictly prohibited except with AREVA's prior written consent
S.Ng – Singapore – November 2011 – p.3 Copyright AREVA 2011 – All rights reserved
Our response
International response
The Fukushima
accident
S.Ng – Singapore – November 2011 – p.4 Copyright AREVA 2011 – All rights reserved
Our current understanding of the events at Fukushima
Initiating events: earthquake and tsunami beyond design basis
AC power loss and consequential damage to cooling capability
H2Hydrogen generation & explosions
Reactor used fuel pools
Accident management: monitoring & control, emergency response
Radioactive release to the environment
External hazard
Damage to cooling
capability
Severe accident Loss of fuel integrity & containment breach
S.Ng – Singapore – November 2011 – p.5 Copyright AREVA 2011 – All rights reserved
Tōhoku earthquake*(Great East Japan Earthquake) on March 11, 2011 (14:46 JST)
Magnitude 9.0
Underwater depth 32km
177km from Fukushima
Most powerful known earthquake to hit Japan; 4th largest earthquake in the world since modern record-keeping began in 1900
Tsunami** wave height estimated at approximately +15 meters (O.P.: Onahama Port base tide level )
Source: *US Geological Society, **TEPCO
Initiating events: combination of natural hazards of exceptional magnitude
S.Ng – Singapore – November 2011 – p.6 Copyright AREVA 2011 – All rights reserved
Source: NISA, JNES, TEPCO
Beyond design basis earthquake
Measured accelerations up to 26% higherthan earthquake design basis values
Automatic shutdown of all operating reactor units (1-3) occurred within seconds
S.Ng – Singapore – November 2011 – p.7 Copyright AREVA 2011 – All rights reserved
Beyond design basis tsunami
Source: TEPCO
S.Ng – Singapore – November 2011 – p.8 Copyright AREVA 2011 – All rights reserved
► An accident at a unit should not impact the surrounding units
► On-site emergency means must be able to cope with several units
A multi-unit accident
Source: TEPCO
Hydrogen explosion at Unit 3 may have disabled some fire pumps used for seawater injection at Unit 2
TEPCO found evidence that the March 15 explosion at Unit 4 was caused by hydrogen that had flown from Unit 3
S.Ng – Singapore – November 2011 – p.9 Copyright AREVA 2011 – All rights reserved
► Loss of off-site power due to earthquake
► Emergency Diesel Generators (DGs) started and worked properly
► Tsunami 55 minutes later rendered DGsinoperable
► Station blackout: all motor-operated pumps rendered inoperable
► Batteries in units 1-2 unavailable (water-damaged) as located under ground level
Source: NISA, TEPCO, IAEA
1
2
3
4
4 lines off-site power supply 13 Diesel Generators (D/G)12 Residual Heat Removal (RHR) Sea Water Systems
(Heat Sink)
5
Loss of power and consequential damage to cooling capability
S.Ng – Singapore – November 2011 – p.10 Copyright AREVA 2011 – All rights reserved
Source: TEPCO
Damage to cooling capability
Power was secured in Unit 6 only (Unit 6 air-cooled diesel generator): combination of diversity in cooling technology (vs water-cooled), location (higher than water-cooled DGs) and hardened power distribution
S.Ng – Singapore – November 2011 – p.11 Copyright AREVA 2011 – All rights reserved
Other sites hit by the tsunami
Source: JAIF, IAEA
► Site ground level (13.8m) above tsunami local height
► Some external power supply lines and seawater pumps remained operational
► Site ground level (8m) above tsunami local height
► One of two bays (upgraded) and an emergency diesel generator remained operational
► External power maintained
S.Ng – Singapore – November 2011 – p.12 Copyright AREVA 2011 – All rights reserved
All assemblies were in Unit 4’s reactor pool on March 11 due to core shroud replacement
Pool water temperature of 84°C on 14 March
Fires on March 15 & 16
No confirmation of fuel damage today
Reactor used fuel pools
Source: NISA
►Need for pool monitoring and make-up water systems (NRC)
►Used fuel should be moved to dry storage as quickly as possible (MIT)
►Used-fuel pools could be housed in containment-like structures separate from the reactor building (MIT)
►The pools might have been fuller without the site central pool, making the situation more problematic
S.Ng – Singapore – November 2011 – p.13 Copyright AREVA 2011 – All rights reserved
Accident management:monitoring & control capabilities
Source: TEPCO
“As there was no power, work inside the building
was conducted in complete darkness, and temporary
instrument power had to be installed separately for
each instrument.”
Station blackout and DC power loss resulted in:
► Shutdown of instruments and control equipment
► Loss of main control room monitoring and operation functions (including communication)
S.Ng – Singapore – November 2011 – p.14 Copyright AREVA 2011 – All rights reserved
“During the initial response, there were several aftershocks, and work was conducted in extremely poor conditions, with uncovered manholes and cracks and depressions in the ground. There were also many obstacles blocking access routes.”
Source: TEPCO
Accident management:emergency response
No on-site mobile generators available
No containment venting procedures
Complete loss of power not tackled
Delays in implementation of alternate cooling functions caused a “cliff-edge”effect leading to the severe accident
S.Ng – Singapore – November 2011 – p.15 Copyright AREVA 2011 – All rights reserved
H2
Hydrogen generation & explosions
Source: RGB
► Include reliable hardened vent in BWR Mark I and Mark II containments (NRC)
►Risks and implications of hydrogen explosions should be revisited and necessary mitigating systems should be implemented (IAEA)
Mark I and Mark II type containments and modified versions of these BWR plants in Japan use inerted containment and wetwell for mitigation of Hydrogen hazards during normal operations
Vents were installed on Japanese BWR plant following Three Mile Island
Source: IAEA
S.Ng – Singapore – November 2011 – p.16 Copyright AREVA 2011 – All rights reserved
Exposure of more than 10,000 workers measured*
9 workers over emergency exposure dose limit of 250 mSv
500+ workers over 100 mSv
No radiation-induced casualty
Casualties at the Fukushima site were caused by the earthquake and tsunami
Fukushima Daiichi dose rate measurements (IAEA)
Radiation dose of workers
*Internal and external as of September 2011
Source: JAIF
S.Ng – Singapore – November 2011 – p.17 Copyright AREVA 2011 – All rights reserved
Reference radiation doses
Source: TEPCO
S.Ng – Singapore – November 2011 – p.18 Copyright AREVA 2011 – All rights reserved
Accident revised to Level 7(INES scale) on 12 April based on the “people and environment” criteria, as a result of radioactivity release estimation
Total release of radioactive material 300-600 PBq Iodine 131-equivalent – one tenth of the Chernobyl accident
Evacuation area of 20km radius on 12 March, with recommended evacuation within 30km radius and in “hot spots” beyond 30km north-west of the plant site
Environmental damage:volatile radioactive release
Source: IRSN
S.Ng – Singapore – November 2011 – p.19 Copyright AREVA 2011 – All rights reserved
Fukushima (IRSN)
2000Rare gas (Xe133)
Radiation impact:Fukushima versus Chernobyl
PBq(1015 Bq)
Iodine 131
Tellurium 132
Cesium 134
Cesium 137
Ruthenium, BariumStrontium
Chernobyl(UNSCEAR*)
Source: IRSN *United Nations Scientific Committee on the Effects of Atomic Radiation 2000 Report
90
60
10
10
<1
7000
1500
1100
60
85
>100
S.Ng – Singapore – November 2011 – p.20 Copyright AREVA 2011 – All rights reserved
On-site Water Contamination Sea Water
Environmental damage:water contamination
Source: TEPCO, WNA Source: NISA
About 110,000m3 of contaminated water
Most contamination from Unit 2 (20 MBq/cm3) versus Units 1 and 3 (0.4 MBq/cm3)
S.Ng – Singapore – November 2011 – p.21 Copyright AREVA 2011 – All rights reserved
Status as of October 27:containment breach and fuel melt
Source: JAIF
Progressive understanding and control of situation
except for core integrity*
*Extent of core melt and core vessel damage still under investigation
S.Ng – Singapore – November 2011 – p.22 Copyright AREVA 2011 – All rights reserved
Our response
International response
The Fukushima
accident
Our immediateresponse
S.Ng – Singapore – November 2011 – p.23 Copyright AREVA 2011 – All rights reserved
Emergency aid and relief supply
Mobilisation and supply of key equipment in record time due to our logistical capabilities
Protective equipment
Radioactivity measurement equipment
Shipment of all aid (including that provided by EDF and German utilities) using the world’s largest cargo aircraft, the Antonov
One million euro donation to Japan Red Cross
S.Ng – Singapore – November 2011 – p.24 Copyright AREVA 2011 – All rights reserved
TEPCO and Japanese government
call on 27 March
Experts dispatched only 48 hours later
Up to 200 people mobilized non-stop
Interdisciplinary skills
Decontamination of effluents
Radiation protection
Used fuel management
Clean up
20 experts dispatched to Japan within one week
Only a few hours to mobilise expertise from our international network
Immediate technical support to TEPCO
S.Ng – Singapore – November 2011 – p.25 Copyright AREVA 2011 – All rights reserved
Construction in radioactive waste building (TEPCO © Copyright)
Our decontamination facility for highly radioactive water was essential in mitigating the crisis at Fukushima
No contaminated water overflow to the ocean
80,000 tons of highly radioactive water decontaminated by mid-September
Closed-circuit cooling of the reactors with decontaminated water made possible
A solution for water decontamination in operation in 2 months
S.Ng – Singapore – November 2011 – p.26 Copyright AREVA 2011 – All rights reserved
Rapid development & deployment of two food monitoring systems
Supply of whole body counters to TEPCO, Fukushima prefecture and hospitals
FoodScreenTM
Radiological Food Screening System
Radiological emergency response and environmental monitoring
FoodSpecTM
Radiological Food Analysis System
S.Ng – Singapore – November 2011 – p.27 Copyright AREVA 2011 – All rights reserved
Our response
International response
The Fukushima
accident
Our continuedresponse
S.Ng – Singapore – November 2011 – p.28 Copyright AREVA 2011 – All rights reserved
A rough idea of reactor generations
Generation I
Generation II
Generation III
Generation III+
Annual increment of nuclear power world wide
S.Ng – Singapore – November 2011 – p.29 Copyright AREVA 2011 – All rights reserved
Three major events influenced the design of our new reactor range
1979 - Three Mile Island :Accident with core melting1979 - Three Mile Island :Accident with core melting
1986 - Chernobyl : Radioactive dispersal1986 - Chernobyl : Radioactive dispersal
Reduce the probability of a severe accident
with core melting
Reduce the impact on the population
in case of asevere accident
Reinforcethe resistance to
any external attack(commercial airplanes)
A B C
2001 – 9/11: Terrorist attackwith commercial airplane2001 – 9/11: Terrorist attackwith commercial airplane
S.Ng – Singapore – November 2011 – p.30 Copyright AREVA 2011 – All rights reserved
Three major events influenced the design of our new reactor range
Reduce the impact on the population in case of
severe accident
Reinforce the resistance to any external attack
(commercial airplanes)
Physical separationRedundancy of critical
components for maintenance and diversity
Core catcherAnnulus and filtration
Airplane-crash-resistantcontainment
(double shell + liner)
A
B
C
Reduce the probability of a severe accident with core
melting
*no emergency evacuation beyond the industrial site, and no long-term relocation
Whatever happens inside or outside the nuclear power plant, no impact on the surroundings*
Main Goals Main Goals AREVA technical options AREVA technical options
S.Ng – Singapore – November 2011 – p.31 Copyright AREVA 2011 – All rights reserved
The defence-in-depth concept…
First line of defence
Second line of defence
Third line of defence
S.Ng – Singapore – November 2011 – p.32 Copyright AREVA 2011 – All rights reserved
…as applied to design safety
Prevention of abnormal
operation and failure
Control of abnormal
operation and detection
of failures
Control of accidents
within the design basis
Control of severe accidents
Mitigation of the
consequences of severe accidents
S.Ng – Singapore – November 2011 – p.33 Copyright AREVA 2011 – All rights reserved
An accident is a complex series of events…
Redundancy
against single failureComplementarity
using both active and passive systems
Diversity
against common cause failure
Emergency power sources
Four safeguard divisions
1
23 4
Core catcher &Containment spray
…so the design must provide the means to remain in control whatever happens
S.Ng – Singapore – November 2011 – p.34 Copyright AREVA 2011 – All rights reserved
These safety objectives werealready largely adopted worldwide
Safety Authorities
France, Finland, UK
WENRA
Utility requirements
EUR
Safety Authority
NRC
Utility requirements
URD
Political decision to move toward Gen III
Gen III requirements
Norms to set up, but political will for Gen III
No official position regarding Gen II or Gen III
Transition towards Gen III
Source: AREVA analysis
S.Ng – Singapore – November 2011 – p.35 Copyright AREVA 2011 – All rights reserved
Our vision of safety post-Fukushima
“What happens to the plant if there is an exceptional natural event?”
“Nuclear plants don’t just shut down. Can you ensure that the plant will continue to cool down?”
“If all else fails, can you guarantee our safety in the short- and long-term?”
ROBUSTNESS OF
COOLING
CAPABILITY
PREVENTION OF
ENVIRONMENTAL
DAMAGE
Imperative 2Imperative 3
RESISTANCE TO
MAJOR
HAZARDS
Imperative 1 But If..But If..
S.Ng – Singapore – November 2011 – p.36 Copyright AREVA 2011 – All rights reserved
Our response
The Fukushima
accident
International response
S.Ng – Singapore – November 2011 – p.37 Copyright AREVA 2011 – All rights reserved
2011 2012 2013
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Further lessons learnedUpdate of regulations
Preliminary inspectionsShort-term measures
Analysis of first lessons learnedSafety checks
Typical scheduleTypical schedule
~9-12 months
x years
~3-6 months
Short-term measures are necessarybut lessons-learned process may last over ten years
Regulatory authorities worldwide launched three kinds of measures
S.Ng – Singapore – November 2011 – p.38 Copyright AREVA 2011 – All rights reserved
Assessments undertaken by European operators before June 1, 2011
Process concerns 14 countries and 143 nuclear power reactors
Scope covers extreme natural hazards (earthquakes, flooding…) and their consequences
June 1 Sep 15
National progress reports
June 2012
EC consolidatedreport to Council
Dec 31
National final reports
Dec 9
EC progressreport to Council
Peer reviewson reports
April 30
A European framework…but safety remains a national prerogative
European agreement on safety checks
S.Ng – Singapore – November 2011 – p.39 Copyright AREVA 2011 – All rights reserved
ASN
STUK
RSK
HSE/ONR
Germany
France
UK
Finland
Status of safety checks in Europe
Results from complementary safety evaluations were sent to the ASN on 15 Sep for report to the government by the end of 2011
Final ONR report published on 11 October, pointing 38 areas where lessons can be learned, but revealing no fundamental safety weaknesses
Preliminary report issued 16 May concluded that there were no new threats nor gaps needing immediate upgrades although some issues requiring further surveys were identified; final report issued end of June
Report issued on 18 May concluded that the operating plants have a “high degree of robustness”, but a political decision was still taken to phase out all nuclear by 2022
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Status of safety checks in the US
First inspections of 104 operating plants issued 20 May concluded that “every plant has the capability” to respond to severe accidents
Near-term review issued 13 July gave 12 “overarching”recommendations and 35 detailed recommendations for near-term and longer-term actions associated with seismic and flooding events, station black out, beyond-design basis events
18-month review due to report at the end of 2012 based on the NRC’sfirst recommendations for development of a new regulatory framework
Recent natural disasters led to successful real-scale exercises
Fort Calhoun (flood), Brown Ferry (tornado) & North Anna (earthquake)
NRC
S.Ng – Singapore – November 2011 – p.41 Copyright AREVA 2011 – All rights reserved
NISA
AERB
Rostekh-nadzor
NNSA
Russia
Japan
China
India
Status of safety checks in Asia and Russia
Merging of NISA with NSC by April 2012; new “comprehensive safety assessments” based on European methodology to be achieved by the end of 2011
Initial survey of plants in operation and under construction completed on 5 August with results and proposed improvements to be made public by mid-2012
Decision taken to create an independent safety authority; a high-level committee report submitted to AERB on 31 August currently under review
Declared the “absence of gaps” following the audit of the Russian fleet on April 18
S.Ng – Singapore – November 2011 – p.42 Copyright AREVA 2011 – All rights reserved
ASN
STUK
NRC
HSE/ONR
US
France
UK
Finland
Position of safety authorities to date on EPR™ design and new build
Construction of Flamanville 3 ongoing during safety check with conclusions from ASN expected 15 November
UK EPRTM design certification ongoing with final design acceptance expected by end of 2012
No shortcomings have been identified on Olkiluoto 3’s resistance to extreme external hazards, and construction is proceeding normally
U.S. EPR™ design certification ongoing
NNSAChina
Approval of new reactor projects suspended since March but construction of Taishan 1&2 ongoing
S.Ng – Singapore – November 2011 – p.43 Copyright AREVA 2011 – All rights reserved
Safety regulation trends: more cooperation & more independence
Safety checks methodology adopted in various parts of the world EU approach adopted by 7 neighbouring countries, Japan, Brazil
International harmonisation to be enhanced IAEA to play a central role
Inspection missions & peer reviews will be further developed WANO to conduct peer reviews of safety in all NPPs within 3 years
Growing independence of safety authorities Positive recent evolution in Japan, South Korea, India
But the effectiveness of the IAEA depends on resources and political will: strengthened international oversight was refused by its board at the September 2011 conference
S.Ng – Singapore – November 2011 – p.44 Copyright AREVA 2011 – All rights reserved
Nuclear program / projects confirmed
New Build program frozen / construction halted
Decision to gradually exit nuclear power /New Build program cancelled
Most countries have not rushed decisions...
S.Ng – Singapore – November 2011 – p.45 Copyright AREVA 2011 – All rights reserved
…but public confidence must be regained
To earn and keep public confidence, there must be no compromise on safety and an imperative forcontinuous improvement
S.Ng – Singapore – November 2011 – p.46 Copyright AREVA 2011 – All rights reserved
Focus on South-East Asia
Source: Map from NIE website