Nuclear Energy After Major Accidents: Economics, Safety, Risk, Scale, Acceptance,.

Transcription

1 Nuclear Energy After Major Accidents: Economics, Safety, Risk, Scale, Acceptance,. Baldev Raj FTWAS, FNAE, FNA, FASc, FNASc.HM,IIM,HF,Blns.NDT,HF,ISNT Director, National Institute of Advanced Studies, Bangalore President, International Council of Academies of Engineering & Technological Sciences Member, German Academy of Sciences; JC Bose Fellow, DST Chairman, Board of Governors, IIT, Gandhinagar; Chairman, Board of Governors, NIT, Puducherry Special Lecture on Global Nuclear Politics and Strategy: Vth Annual Residential Workshop for Young Scholars, International Strategic and Security Studies Programme (ISSSP), NIAS, Bangalore 7 th May 2015

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6 Ref: Why it matters by Mike Orcutt

7 PHWR Evolution 2000s EXPANSION, COMMERCIALISATION & ECONOMY OF SCALES 700 MWe & above FUTURE PROJECTS 1980s 1970s INDIGENISATION TECHNOLOGY DEMONSTRATION Madras Atomic Power Station (2 220 MWe) 220 MWe 1990s CONSOLIDATION 1980s STANDARDISATION Design layout of 700MW plant 2000s COMMERCIALISATION RAPP-3&4 RAPS-1&2 MAPS-1&2 NAPS-1&2 KAPS-1&2 KGS-1&2 RAPP-5&6 KAIGA-3&4 540 MWe TAPS-3&4 Scalability, time schedule, safety record and structure, waste management, public and policy makers perspective and acceptance are key issues 7

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9 LWRs:Russian, U.S, French and others Kudankulam 1 has been commissioned and is producing full power. Kudankulam 1 & 2 9

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12 NUCLEAR REACTOR SAFETY 1. To match nuclear heat generation with heat removal. Heat generated should be within design (Reactivity Control) Heat removal to keep Fuel temperatures to be within design (Fuel Cooling) 2. Confinement of Radioactivity 12

13 Heat produced should be equal to heat removed at all times Including even when plant is not operating 13

14 Defense in Depth PREVENT ACCIDENTS MITIGATE THEIR IMPACT, IF THEY HAPPEN KEEP READY EMERGENCY PLAN 14

15 MULTIPLE BARRIERS TO PREVENT RADIOACTIVITY RELEASE Fuel Fuel Clad Primary Coolant Inventory Containment Exclusion Boundary 15

16 Fukushima Accident: An overview, Akira Omoto, Univ. of Tokyo, Japan, Icapp2011, 2 May 2011

17 Fukushima Accident: An overview, Akira Omoto, Univ. of Tokyo, Japan, Icapp2011, 2 May 2011

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24 Accident at Fukushima On March 11, 2011, Earthquake of Magnitude 9.0 hit the Fukushima Dai-ichi & Dai-ni About 1 Hour later Tsunami waves of height 15 meters above reference sea level followed At Fukushima Dai-ichi out of six, unit 1 to 3 were in operation, and unit 4 to 6 were in maintenance modes Units 1 to 3 automatically scrammed at the Earthquake, Tsunami caused loss of external power supplies and almost all in-house AC power supplies

25 Accident at Fukushima (effect) Reactors and spent fuel pools at the Fukushima Dai-ichi lost their cooling capabilities. Explosions in RB of units 1, 3 and 4 due to hydrogen released from possible core damage Unit 2 also suffered core damage with explosion inside containment Dai-ni units 1-4 survived because of off-site power remained available & efforts of plant staff to restore power to essential equipment Large scale release of radioactive material from Fukushima Dai-ichi NPS. The event rated at INES level-7

26 Emergency Measures at Fukushima 110,000 people within 20km of the site evacuated in four stages Continuous sampling of food, water and milk carried out in all prefectures Radioactivity monitoring in air and sea (as far as 10km from shore) Arrangements for taking care of patients evacuated from the said area Team of Psychiatrists posted to counsel evacuated people Many people are still not able to return to their home, and radioactive contamination has caused serious impact in extended areas. 26

27 Present Status of Fukushima Dai-ichi NPS All reactors are in cold shutdown condition Nitrogen gas is injected directly in to RPVs and PCVs Based on current release rates dose at site boundary <0.1 msv/yr Closed loop cooling of all spent fuel bays achieved Restoration measures Installation of reactor cover in Unit-1 completed Removal of debris from top of Unit 3 & 4 in progress Centralized monitoring system installed at main anti-eq building Construction of shield wall to prevent sea water contamination

28 Recovery Action: Ref: Fukushima Daiichi Accident: Recovery action, organization, environmental impact, Hideki Masui, Tokyo Electric Power Company, ICAPP2011, France, 3 May 2011

29 Ref: Remediation efforts in Japan, Masaru Moriya, Fukushima Decontamination Promotion Team, LENR Headquarters, Oct. 16, 2011

30 Response around the World Germany ordered immediate shutdown of 8 NPPs Switzerland and Italy put on hold their plans for new construction A large number of major players such as Canada, France, USA, Ukraine, UK supported the existing programme Countries with major expansion plans such as China, India, Russia, South Korea confirmed continuation of programme However, all countries decided to re-assess safety and strengthen if necessary

31 International Organizations IAEA sent an International Experts Team to Fukushima on Fact Finding Mission OECD-NEA and IAEA convened Ministerial Conferences to discuss the impact of the event and proposed actions IAEA Action Plan Improve safety standards in areas such as defense in depth, beyond design basis considerations, severe accident management including at multiunit site Improve national, regional and international emergency preparedness and response Improve effectiveness of Internationally binding conventions Increase the rigour and frequency of international peer reviews of national programme

32 Global Trends Post Fukushima 1/2 NPPs connected to grids after the Fukushima accident Chashapp 2 (300 MWe, PWR, Pakistan) on 14th March Lingao 4 (1000 MWe, PWR, China) on 3rd May CEFR (20 MWe, FBR, China) on 21st July Bushehr 1 (915 MWe, VVER, Iran) on 3rd September Kalinin 4 (950MW,VVER,Russia) on 24 Nov.2011 Quinshan 2-4 (610 MW, PWR, China) on 25 Nov 2011 Shin-Wolsong 1 (960 MW, PWR, Korea on 27 Jan 2012 Shin-Kori 2 (960 MW, PWR, Korea) on 28 Jan 2012 Ohi-3 (1100 MW, PWR, Japan) restarted on 2 July 2012 Ohi-4 to restart soon

33 Global Trends Post Fukushima 2/2 NPPs Planned or being constructed China: 26 under construction & additional reactors are planned Russia: 11 under construction. 14 reactors planned. India :7 under construction, more planned Pakistan, Slovakia, Ukraine(2 each) under construction Argentina, Brazil, Finland, (1 each) under construction France: EPR at Flamenville being constructed & second to follow at Penly. USA: Proposals for over 20 new reactors. UK: Four 1600 MWe units planned for operation in Bangladesh, Vietnam, UAE and Turkey initiated action for setting up its first NPPs (VVER) A total of 62 NPPs ( MW) are being constructed in 13 countries.

34 Indian Response The Government immediately ordered review of the safety of NPPs to withstand severe natural events AERB directed NPPs to undertake immediate self assessment against external events NPCIL conducted safety assessment of its NPPs to deal with severe external events AERB carried out special regulatory inspections of all NPP sites to assess/review their capability to withstand Severe external events AERB constituted a high level committee to review safety of NPPs against external events AERB has reviewed the utility plans for safety enhancements and will monitor their progress.

35 Safety Enhancements in Indian NPPs Based on Special safety reviews after major events and PSRs Seismic re-evaluation and consequent strengthening of SSCs, where necessary Reassessment of DBFL with specific consideration of upstream dam failure for in-land sites Reassessment of Tsunami Hazard at all coastal sites Construction of 12.2 m high Tsunami protection wall at Kalpakkam Installation of additional DGs at higher elevation in old NPPs Re-location of UPS system and diesel driven fire water pumps to higher elevation Installation of Tsunami early warning system

36 Safety Enhancements in Indian NPPs Based on Special safety reviews after major events and PSRs Physical separation of redundant trains of safety systems (equipment and power & control cables) to avoid CCF Fire safety enhancement (Strengthening fire barriers, Diverse fire detection methods) Enhancement in ECCS by addition of high pressure core injection system and modification in ECCS pump suction strainers Diverse air intake to improve main control room habitability Incorporation of Supplementary Control Room Augmentation and hardening of communication systems

37 Addressing Fukushima Major recommendations of AERB committee Higher degree of conservatism in assessment of the intensity and combination of EE (Simultaneous severe EQ and Tsunami not possible) While safety systems design is governed by DB EE, any cliff edge effect to be avoided Enhancement of defense-in-depth by use of diverse, physically separated and environmentally hardened systems along with use of passive systems with atmosphere as ultimate heat sink Hook-up provisions to add water to further enhance cooling capability in primary system & SFSB Strengthening measures and procedures to deal with severe accidents Creation of environmentally hardened & well equipped emergency response facility with provisions to obtain plant information, communication with concerned agencies and to house essential personnel

38 New Generation Reactors Standardised designs to reduce capital cost & construction time Better fuel economy, higher availability & longer life Use of inherent & passive safety features Do not require AC power, external services or operator action for at least 72 hrs Reduced possibility of core melt accidents and radiological release in the public domain Provision for mitigation of severe accidents involving core damage Resistance to external damage including aircraft impact New reactors already incorporate most of the identified improvements

39 Safety Culture This cannot happen here syndrome Complacency Commercial pressures Safety culture Priority to safety, at all times, at all levels Continuous improvement in safety Constant vigilance This applies to both the utility and the regulator

40 Can we prevent an accident? What we know and what we can think of What we don t know and can t imagine We can only protect against what we can think of and perhaps a little beyond

41 Summing up : The most important lessons Continuous and proactive safety assessment and improvements based on Operating Experience : National / International, Nuclear/ Non-nuclear New Technical findings and results of R & D Interaction with International community Severe Accident Consideration In siting and design of NPPs Well conceived and rehearsed SAMG and Emergency Plans To ensure no long term impact in the public domain Improving Public Confidence Sustained communication with public based on facts and realistic perspective

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