#1REVIEW of INDIAN NRPS POST FUKUSHIMA EVENT#2Outline The Subsequent slides cover the following ➤ NPCIL Task Forces ➤ Review process at NPCIL. ➤Fukushima Event and its Progression ➤ Post Fukushima review of Indian NPPs. ➤ Summary of recommendations by Task Forces ➤ Action plan#3NPCIL TASK FORCES#4NPCIL Task Forces Accident at Fukushima Nuclear Power Plants (NPP) in Japan occurred on 11th March, 2011, due to Earth Quake followed by Tsunami. On 15th March, 2011, CMD NPCIL constituted four task forces to review consequences of occurrences of similar situations in INDIAN NPPs, which broadly fall in four categories. They are 1. Boiling Water Reactors (BWR) (TAPS 1&2) 2. Pressurized Heavy Water Reactors (PHW Rs) at RAPS 1&2 3. PHWRs at MAPS 1&2 4. Standard PHW Rs From NAPS onwards • These task force were asked to assess safety of Indian NPPs assuming non availability of motive power and design water supply routes. All the task forces submitted their reports based on the information available on Fukushima event at that time.#5NPCIL Task Forces Task Force Reactor Type Committee Members A1 TAPS 1&2 (BWR) A2 RAPS 2 (PHWR) S. Bhattacharjee (Retired Station Director) K.R.Anil Kumar (Chief Engineer) P.K.Malhotra (Chief Engineer) V.S.Daniel (Technical Services Superintend, TAPS 1&2) D.K.Goyal (Executive Director) S.C.Rawal (Chief Engineer) M.Singhal (Additional Chief Engineer) H.W.Pandey (Additional Chief Engineer) S.K.Jain (Technical Services Superintend, RAPS) S.Krishnamurthy (Executive Director) M.Ramasomayajulu (Technical Services Superintend, MAPS) N.R.K.Murthy (Additional Chief Engineer) A3 MAPS-1&2 (PHWR) R.R.Sahaya (Additional Chief Engineer) Standard A4 PHWR S.Chandramouli (Additional Chief Engineer) S.G.Ghadge (Executive Director) U.S.Khare (Associate Director) H.P.Rammohan (Additional Chief Engineer) S.K.Datir (Additional Chief Engineer),#6NPCIL Task Forces Later on two more task forces were formed by CMD NPCIL, to assess safety of Indian NPPs under construction, assuming non availability of motive power and design water supply routes. ➤ One task force for VVER, Pressurized Water Reactors (PWR) under construction at KKNPP. & One for 700 MWe, PHW Rs under construction at KAPP 3&4 and RAPP 7&8. Task Force Reactor Type A5 A6 KKN PP (PWR) 700MWe (PHWR) Committee Members S. Krishnamurthy (Executive Director) U. S. Khare (Associate Director) K. R. Anilkumar (Chief Engineer) Suresh Kumar Pillai, (Technical Services Superintendent, KKNPP) R. K. Gupta, (Deputy Chief Engineer) H.P.Rammohan (Additional Chief Engineer) S.Hajela (Additional Chief Engineer) K.K.De (Additional Chief Engineer) B.G.Baliga (Additional Chief Engineer) Ch. Srinivasa Rao (Additional Chief Engineer) S.D.Puneta (Additional Chief Engineer) Sanjeev Sharma(Sr. Executive Engineer) C.R.Kakde (Sr. Executive Engineer)#7SAFETY REVIEW PROCESS AT NPCIL#8• Continued Monitoring and Periodic Safety Assessment ➤ Safety is a moving target. ➤ Continued monitoring, periodic safety assessment and improvement of Indian nuclear power stations including national and international operating experience, are performed by NPCIL as well as by the Regulatory authority (AERB). • A variety of safety reviews and assessments are carried out as per the established requirement, which include the following: Routine reviews inclusive of review of Significant Event Reports Reviews of proposed modifications in design / operating procedures to assess their impact on plant safety Safety assessments for renewal of authorization Safety assessments in response to major incidents and operating experience both nationally and internationally Safety assessment related to major refurbishment Safety assessment for Plant life extension Details are covered in Section-2 of Report "Safety Evaluation of Indian Nuclear Power Plants, Post Fukushima Incident".#9LATEST PERIODIC SAFETY REVIEW DONE on INDIAN NPPS Unit Commercial Operation Periodic safety review (PSR) Remarks TAPS-1&2 1969 (Unit-1) 2011 Authorisation up to Dec 2011 1969 (Unit-2) RAPS-1&2 1973 (Unit-1) 2009 Authorisation up to 2014 1981 (Unit-2) MAPS-1&2 1984 (Unit-1) 2005 Authorisation up to 2011 1986 (Unit-2) NAPS-1&2 1991 (Unit-1) 2003 Authorisation up to 2013 1992 (Unit-2) KAPS-1&2 1993 (Unit-1) 2004 Authorisation up to 2014 1995 (Unit-2) RAPS-3&4 2000 (Unit-1) Due on April-2012 Authorisation up to 2012 2000 (Unit-2) KGS-1&2 2000 (Unit-1) Due on November-2011 Authorisation up to 2012 2000 (Unit-2) 2007 (Unit-1) Due on -2017 KGS-3&4 2011 (Unit-2) Due on -2017 Permission to operate received from AERB 2010 (Unit-1) Due on -2020 RAPS-5&6 2010 (Unit-2) Due on -2020 TAPS-3&4 2005 (Unit-1) 2006 (Unit-2) Review under process Permission to operate received from AERB Authorization up to 2011#10• • Lessons Learnt from Events and Implementation Status In addition to regular safety reviews, NPCIL reviews all national and international nuclear events and implements the subsequent recommendations for safety up gradation. Some events at NPCIL operating stations, described includes Fire incident at Narora Atomic Power Station (NAPS), March 1993. Tsunami event at Madras Atomic Power Station (MAPS), December 2004. Some international events reviewed at NPCIL, given below ➤ Three Mile Island (TMI) accident in USA ➤ Chernobyl accident in Ukraine#11NAPS-1 FIRE INCIDENT#12NAPS-1 Fire Incident in March, 1993 Fire in Turbine Generator (TG) hall initiated by sudden failure of two turbine blades. This resulted in vibrations, leading to rupturing of hydrogen seals and lube oil lines, culminating in a fire. Fire spread to several cable trays, relay panels, etc., This resulted in complete failure of power supply (from grid + Diesel generator/batteries) within 7 minutes of incident. Reactor was shutdown by shutdown system (Fail safe design). Extended Station Blackout at NAPS 1 lasted for a period of 17 hours. Core cooling was maintained by natural circulation of coolant (Thermosyphoning ) by providing fire water to the steam generators as heat sink. (see next slide)#13B Passive core cooling by natural circulation A FUELLING MACHINE AIRLOCK REACTOR BUILDING STEAM GENERATOR PHT PUMP REACTIVITY MECHANISMS SRVS ASDVS H.P. TURBINE MSIVS MOISTURE SEPARATOR REHEATERS L.P. TURBINE GENERATOR CSDVS DEAERA TING HEATERS CONDENSER COOLING WATER GENERATOR TRANSFORMERS HP. HEATERS BFPs L.P. HEATERS CEPS COOLING WATER EQUIPMENT STEAM CONDENSATE FEED WATER PHT MODERATOR ELECTRICAL Schematic Diagram of Indian PHWR as Elevation difference between Steam Generators (B) and Reactor Core (A) provides driving force for natural circulation of coolant known Thermosyphoning. Through this phenomenon decay heat is removed by supplying fire water to steam generator.#14NAPS-1 FIRE INCIDENT There was no radiological impact of the incident either on the plant- workers or in the public domain. The incident was thoroughly recommendations reviewed and were implemented at all other stations. Implementation status of View of NAPS from river side recommendations for NAPS-1 fire event. N.B: Detailed reports are given as links to Bold Italics#15Tsunami Incident at Eastern Coastline of India On Dec 26, 2004 - Tsunami struck the eastern. coastline of India, where MAPS units are located. Prior to event MAPS-2 was operating at full power and MAPS-1 was under shutdown. Water level risen due to Tsunami causing submergence of low lying areas. Reactor brought to safe shutdown state and core cooling continued as per design. Power supply from grid was available but emergency power supplies from Diesel Generators (DG) started and kept running as precautionary measure. There was no radiological impact of the incident either on the plant-workers or in the public domain. Emergency Diesel Generator (EDG), located at 12.5 m elevation, which is 2m above the Tsunami height observed (See photograph in next slide). View of MAPS from sea side#16Emergency Diesel Generator-5 at MAPS DIESEL GENERATOR #5 EDG level = 12.518 m Flood Level observed in Tsunami event at MAPS = 10.5 m RVO 16#17Implementation of lessons learnt from International events For following international events in nuclear industry like Three Mile Island (TMI) in USA and Chernobyl in Ukraine, detailed independent safety reviews were conducted and key lessons learnt were implemented in all plants. Implementation status of Three Mile Island (TMI) recommendations for TAPS-1&2 and PHWR. Implementation status of Chernobyl recommendations for TAPS- 1&2 and PHWR. N.B: More information and detailed reports are given as links to Bold Italics#18FUKUSHIMA Event and its progression#19Fukushima Event On 11th March 2011, Earthquake of magnitude 9.0 struck near Fukushima, Japan. It was followed by Tsunami of ~15 meter high waves after an hour of earthquake. ■ Magnitude of earthquake and tsunami wave height were more than considered in the design. There were total 13 NPPs located in the affected zone, out of which 10 were operating and 3 were under maintenance outage. All 10 operating plants at the affected area automatically shutdown on sensing the earthquake. Out of 13 NPPS in the affected zone, 4 NPPs at Fukushima Daiichi got affected. Remaining 9 plants were safe. All the 6 plants located in Fukushima Daiichi were of BWR type.#20Reactors operating in Affected Zone Status of the Nuclear Power Plants after the Earthquake Every efforts and measures have been taken at Fukushima Daiichi nuclear power plants. Other nuclear power plants in Japan are in Tomari 123 normal operation or safely shutdown. Genkai Kashiwazaki Kartwa Onagawa XEPICENTER AFFECTED AREA of the quake Fukushima Daiichi In Operation : 54 Construction: 2 Affected Zone: 13 [Fukushima Daiichi (6),Fukushima Daiini(4) & Onagawa (3)] Shika Tohoku/Higashidori Turugo Mihama 123 Oh 1234 Takahama 1234 123456 Shimanel Tokyo Fukushima Daini Tokai kato Sendai 123 345 Hamaoka Accident with Nuclear Fuel Damage Suspected Accident without Nuclear Fuel Damage Suspected Safe Safe (Not affected by the quake) JAIF#21Status of Reactors located in the affected zone of Japan Location Units Status after Earthquake Unit 1 Automatic Shutdown Unit 2 Automatic Shutdown Unit 3 Automatic Shutdown Fukushima Daiichi Unit 4 Maintenance Outage Unit 5 Maintenance Outage Unit 6 Maintenance Outage Unit 1 Automatic Shutdown Unit 2 Automatic Shutdown Fukushima Daiini Unit 3 Automatic Shutdown Unit 4 Automatic Shutdown Unit 1 Automatic Shutdown Onagwa Unit 2 Automatic Shutdown Unit 3 Automatic Shutdown In spite of facing the similar magnitude of Earthquake/ Tsunami, only four (unit 1-4 of Fukushima Daiichi) out of thirteen plants were affected and remaining nine plants remained safe. There are lessons to be learned from both.#22Secondary Containment: Area of explosion at Fukushima Daiichi units 1 and 3 Steel Containment Vessel Primary Containment Boiling Water Reactor Design At Fukushima Daiichi Possible area of explosion at Fukushima Daiichi 2 Suppression Pool (Torus) • Spent Fuel Pool Status Unit-3&4 : Low water level :Fuel Rods Damaged • Unit-3 • Unit-5&6 : High Temperature Spent Fuel Pool Reactor Vessel Core and Fuel Damaged in Unit- 1,2 & 3 Seawater Is Being Pumped Into Reactor Vessels at Units 1, 3 and 4#23Units at Fukushima-Daiichi Capacity Unit Commercial Operation Construction Start (MWe) Supplier start No.1 460 April, 1967 March, 1971 GE No.2 784 Jan, 1969 July, 1974 GE/Toshiba No.3 784 Aug, 1970 March, 1976 Toshiba No.4 784 Sep, 1972 Oct, 1978 Hitachi No.5 784 Dec, 1971 April, 1978 Toshiba No.6 1100 May, 1973 Oct, 1979 GE/Toshiba Total Power: 4696 MWe#241. 2. 3. 4. Physical Causes of Fukushima Event In the accident of Fukushima Daiichi NPPs, huge Earth quake of magnitude 9 followed by Tsunami of Height 15m, caused serious situation common to units 1-3 such as Loss of external power supply from grid due to Earth quake. Emergency power sources like DG, Batteries continued for around 1 hr, and failed subsequently due to Tsunami. Loss of core cooling (Decay heat_removal function) due to unavailability of all sources of power supply. Loss of Reactor decay heat removal resulted in fuel over heating- Metal Water Reaction Hydrogen Generation & Explosion inside the outer Building. - N.B: More information given as links to Bold Italics.#25Fukushima Event As per initial analysis for Unit 4, the scenario was concluded as follows: > The unit was under refueling shut down, ➤ Entire core was stored in Spent Fuel Pool located on Reactor service floor. > The unavailability of motive power resulted in loss of Fuel Pool cooling and rise in pool water temperature. > Exposure of Spent Fuel to air resulted in metal water reaction which further heated up the fuel. > Hydrogen generated during the process formed an explosive mixture. and resulted in explosion, damaging the roof of the reactor building in which spent fuel pool is located. Typical BWR Spent Fuel Pool#26Fukushima Event ■ However, updated information received indicates that as a result of containment venting from other unit (Unit-3) and inter- connecting lines passing, hydrogen backed up and accumulated in Unit 4 also, and led to explosion. In spite of this, spent fuel cooling is still a concern in this kind of situations.#27Root Cause of the Event Note: -All operating units when earthquake occurred were automatically shut down. -Emergency D/Gs have worked properly until the Tsunami attack. ①Loss of offsite power due to the earthquake Tsunami (estimated more than 10m) Seawater level Seawater Pump Reactor Building Turbine Building Grid Line D/G D/G Inoperable due to Tsunami flood Elevation: about 10m 1+2 Station Block Out All Motor Operated pumps (including ECCS pumps) became inoperable#28Maximum Wave Height of tsunami considered at the Fukushima NPP site was 5.7 m. Maximum Maximum Ground Level Assumed Height Tidal Level 2011 East Tsunami 1960 at the site Height Chilean Tsunami 1965 Typhoon Japan Earthquake No.28 Unit 1, 2, 3 and 4 O.P.+10m 5.5 m 15 m (*4) O.P.+3.122 7.94m (Observed m Unit 5 and O.P.+13m 5.6 m by TEPCO) 6 Note: The level of seawater pump for cooling system was set at O.P. +5.6 m. Note: O.P.: ONAHAMA Peil (Average tidal level at Onahama is set as a referenced point. Onahama is about 50km south of the site, and the level of the observation point is -0.918 m above sea level.) Note(*4): TEPCO released the observation results on April 9, 2011. In the area of Units 1 to 4 most buildings were immersed in 4 to 5 m seawater. In the area of Units 5 and 6 building were immersed In 1 m seawater.#29Aerial View of Fukushima Daiichi NPPs 1-4#30ACCIDENT PROGRESSION in FUKUSHIMA REACTORS#31Steam relief to Wet well following rise of pressure in the Pressure Vessel Drywell Wetwell (Torus) GRADE LEVEL Reactor Bldg H#32- Pressurisation of wetwell & Opening of drywell - Partial core uncovery metal water reaction - hydrogen - clad damage – steam, non- condensibles, fission gases come to dry well Drywell Wetwell (Torus) GRADE LEVEL Reactor Bldg H -#33Drywell Pressurization Drywell Wetwell (Torus) GRADE LEVEL Reactor Bldg H#34- Drywell pressurisation – venting - Accumulation of H₂ gas in secondary containment and pressure build-up Drywell Wetwell (Torus) GRADE LEVEL LEAK H₁₂+ Steam H#35Attainment of explosive H2 concentration in secondary containment - BURSTING & release (Units 1&3) ↑ Drywell Wetwell (Torus) GRADE LEVEL LEAK H₂+ Steam ##36- Attainment of explosive H2 concentration in Wetwell – BURSTING & release (Unit-2) ми Reactor Bldg Drywell Wetwell (Torus) GRADE LEVEL H#37TSUNAMI EVENT at Fukushima Daiichi Plants TEPCO#38TSUNAMI EVENT at Fukushima Daiichi Plants 11 19#39Aerial View of Fukushima Daiichi NPPS 1-4 Unit 1 heavy oil tank lost light oil tanks Seawater pumps Unit 2 light oil tank Seawater pumps light oil tank Unit 3 Unit 4 Seawater pumps#40POST FUKUSHIMA REVIEW OF INDIAN NPPS#41Status of Indian NPPs Operating plants: 2 Boiling Water Reactors (BWR) of 160 MWe each. • 16 Pressurized Heavy Water Reactors (PHWRs) of 220 MWe each. • 2 PHWRs of 540 MWe each. Plants Under Construction: ● • 4 units of 700 MWe PHWRs are under construction. 2 units of Russian WWERS- Pressurized Water Reactors (PWRs) of 1000 MWe each are under advanced stage of construction. The present total installed capacity of nuclear power in India is 4780 MWe. The accumulated experience of safe operation through these reactors is 330 reactor years.#42Operating Nuclear Power Plants in India TARAPUR-1&2 RAJASTHAN-1 to 6 MADRAS-1&2 KCS1 to 4 NARORA-1&2 TARAPUR 3&4 KAKRAPARA-1&2 KAIGA-1 to 4 Total Capacity 4780 MWe#43Reactors Under Construction KK 1&2 (2x1000 MWe) RAPP-7&8 (2x700 MWe) KAPP-3&4 (2x700 MWe) 01/07/20153 Total Capacity under construction 4800 MWe#44Safety in TAPS-1&2 Tarapur Atomic Power Station (TAPS-1&2) is the first 2x160 MWe Boiling Water Reactor (BWR), started Commercial Operation in October 1969. The plant is located in Tarapur, in the Arabian sea coast, North of Mumbai, India. Safety upgrades and renovation completed in year 2005. Details of safety upgrades covered in section 3 of TAPS 1&2 task force report. Salient Safety features of TAPS-1&2 Reactor are: View of TAPS from sea side TAPS-1&2 Primary Containment Volume to Power ratio is 10 times more than Fukushima NPP which means slow build up of pressure in containment Passive systems for decay heat removal (Emergency Condenser, can be valved in manually without any requirement of power supply) - Adequate to cool the core for 6 hours (Refer Schematic on Next Slide).#45TAPS-1&2 Safety vis-a-vis Fukushima Emergency condenser in TAPS 1&2 can be valved in manually (without any power supply). to remove decay heat passively (in case of Fukushima like event). It is adequate to cool the core for 6 hours. REACTOR BUILDGING REACTOR BUILDGING REACTOR BUILDING TURBINE DRIVEN PUMP 白口 RCIC SYSTEM REACTOR Ground Elevation EMERGENCY CONDENSER COMMON CHAMBER (390000 cu.ft) EMERGENCY CONDENSER DRYWELL CORE SUPPRESION POOLS (110000 Cu.ft Air Volume in Each) CORE (53000 Cu.ft of water in each supression pool) TAPS 1&2 Reactor REACTOR ECCS SYSTEM SEAWATER COOLED Hs SPRAY RHR RPV RCP RCP STEAM TO TURBINE FEED WATER HIRE ENGINE BOCS PUMP CONTAINMENT WATER SUPPLY SEA WATER SUPPRESSION POOL SUPPRESSION Fukushima Reactor#46Safe Shutdown Safety in Indian PHWRS Reactor Safety Decay Heat Removal Containment Systems & Features • Fast Acting • Independent • Passive (Shut off Rods, Control Rods and Poison Injection for Long term shutdown) Systems & Features Active & Passive • Backup Systems [Emergency Core Cooling System (ECCS), Suppression Pool, Inventory in Calandria & Calandria Vault, Fire water injection into Steam Generators] Systems & Features • Double Containment •Inner Containment design for Design Basis Accident (DBA) pressure • Secondary Containment under negative pressure •Engineered Safety Features (ESF)#47Shutdown systems in Indian PHWRs There are two fast acting, independent shutdown systems known as Primary Shutdown System (PSS) and Secondary Shutdown System (SSS). SHIELDING PLUC ELEMENT DRIVE UNIT CALANDRIA VAULT FAST ACTING SOLENOID VALVES HELIUM TANK TOP HATCH BEAM GUIDE TUBE POISON TANK CALANDRIA NOZZLE CALANDRIA GUIDE TUBE LOCATOR ASSEMBLY LLITHUM PENTABORAN SOLUTION FIG. 10.3.4 SHUT-OFF ROD MECHANISM GENERAL ARRANGEMENT (500 MWe) SCHEMATIC OF PSS ROD FIG. 10.3.5: LIQUID SHUT-OFF SYSTEM (220 MWe) SCHEMATIC OF SSS LIQUID POISON TUBE#48Heat Sinks in Indian PHWRs In standard PHWRs, in case of loss of all sources of power supplies, the time available to restore heat sinks is shown below. 625 tons water in Calandria Vault which takes 36 hours to boil off. O O O O OOOO OOOO 260 tons water as moderator which takes 13 hours to boil off. OOOO 48#49EARTHQUAKE- TSUNAMI MAKARAN FAULT 900 KMS TARAPUR KALPAKKAM ➤Tsunamigenic locations for Indian coast are far away, so more time will be available for operator action. So plants which see Tsunami will not get affected by Earthquake. Those plants which Earthquake, wont see Tsunami. Tsunamigenic locations are far away, Tsunami intensity seen by Indian NPPs is also small. 1300 KMS ONLY KUDANKULAM FAR SUNDA ARC FIELD SOUR ➤ As CES 1500KMS TECTONIC PLATE BOUNDARIES CHAGOS RIDGE 49#50Comparative Seismic Hazard None of Indian NPPs see the magnitude of Earthquake as seen in Japan RUSSIA Islamabad Lahore Delhi NAPS Vladivostok N. KOREA Karachi Onagawa S. KOREA Sendai Earthquake $9H, 11 March, 2011 RAPS NagoyFukushima Dai-ichi Fukushima Daini Seoul Pusan Tokai KAPS 0000 Osaka Tokyo Yokohama TAPS Bombay Kathmandu Calcutta Thimphu Shanghai CHINA SEISMIC ZONES AND LOCATIONS OF 9M, MARCH 2011 EARTHQUAKE AND AFFECTED NPPS BY TSUNAMI 0 PEAK GROUND ACCELERATION (ms) 10% PROBABILITY OF EXCEEDANCE IN 50 YEARS, 475-year return period Hyderabad KGS Bargalore. Madras MAPS Yangon KK Colombo SEISMIC ZONES AND LOCATIONS OF INDIAN NPPS PEAK GROUND ACCELERATION (mys') 10% PROBABILITY OF EXCEEDANCE IN 50 YEARS. 475-year return period 0.2 0.4 0.8 1.6 2.4 3.2 4.0 4.8 0 0.2 0.4 LOW HAZARD MODERATE HAZARD HIGH HAZARD VERY HIGH LOW HAZARD MODERATE HAZARD 0.8 1.6 2.4 3.2 HIGH HAZARD 4.0 HAZARD 4.8 VERY HIGH HAZARD#5140° 30° 120° TSUNAMIGENIC LOCATIONS JAPAN vs. INDIA 130 km from Fukushima 130 140° DISTANCE OF 9.0 EQ IS 130 KMS EAST FROM SENDAI USGE 120° 130 TOKYO 150° 900-1600 km away from Indian coast 40° BOUNDARY BETWEEN PACIFIC 30 PLATE & ASIAN PLATE 140° 150° MAKARAN FAULT 900 KMS TARAPUR 1300 KMS SUNDA AR 1500KMS TECTONIC PLATE CHAGOS RIDGE BOUNDARIES NEAR EAST COAST OF HONSHU, JAPAN 2011 03 11 05:46:23 UTC 38.32N 142.36E Depth: 24.4 km Earthquake Location From the above, it can be seen that Tsunamigenic locations are far away from Indian Coast in comparison with Fukushima#52Assessment of Seismic Margins Station Seismic Magnitude Zone (Richter Scale) Epicentral Distance (km) Design PGA (g) Conservative Margin (PGA) (g) TAPS 1,2 III 5.7 16 0.2g 0.337 to 1.83 @ RAPS-1,2 II 6.0 40 0.1g 0.233 to 2.26 @ MAPS-1,2 || 6.0 20 0.156 g 0.233 to 2.26 @ NAPS-1,2 IV 6.7 12 0.3g 0.6 # KAPS-1,2 III 6.5 30 0.2g 0.6 # KGS-1,2,3,4 III 5.7 12 0.2g 0.6 # RAPS-3,4,5,6 II 6.0 40 0.1g 0.6 # TAPS-3,4 III 5.7 16 0.2g 0.337 to 1.83 @ KK 1&2 II 6.0 33 0.15 0.6# @: These values are based on analysis conducted during the seismic re-evaluation of the plants based on permissible stress values. Very few components are close to the low Peak Ground Acceleration (PGA) values, majority are close to 0.6g PGA. #: Design of new plants from NAPS onwards was done for allowable stress values However, the actual stress values are much less than the allowable values. Based on the analytical values calculated for TAPS 1&2, RAPS 1&2 and MAPS 1&2 and performance of Kasiwaziki Kariwa and Shika NPP's in Japan, GSECL's plant at Jamnagar and Panendhro, IFFCO plant at Kandla, the Seismic Margin Assessment PGA will be about two to three times those of the analytical values.#53Pictorial View of Flood Margin at Coastal Sites Finished Floor Level Wave Run-up Tsunami Height Max High Tide Mean Sea Level SEA Sea Bed Reactor Building TAPS MAPS KKNPP 32.3 m 10.668 m 8.0 m 31.81 m 10.5 m 5.42 m 28.81 m 6.896 m 0.94 m 25.97 m 6.096 m 0.0 m # Reference Level#54Flood levels and margins for inland sites Station Original designed flood level Revised levels taken for assessment (in meter) Emergency power DGs elevation (in meter) Margin available (in meter) # (in meter) RAPS-1&2 354.20 359.60* 356.6 (Original DGs) 366.6 (Retrofitted DG) 7.00 NAPS-1&2 180.80 187.30 6.50 KAPS-1&2 50.30 51.30 1.00 RAPS-3&4 359.60 384.30 24.70 Design is adequate- revision not required RAPS-5&6 359.60 393.30 33.70 KGS-1&2 38.90 41.30 2.40 KGS-3&4 38.90 41.60 2.70 •For RAPS-1&2, Upstream dam break is considered for revision of flood level for assessment. # Even though margins are available, Task forces assumed no margin and recommended various measures. Beyond this margins, core cooling can be maintained through hook up arrangements as recommended by task forces.#55Pictorial View of RAPS 1-6 from lake side RAPP-7&8 RAPS-5&6 RAPS-3&4 RAPS-1&2 NORMAL LAKE LEVEL All RAPS Plants (RAPS 1-8) are at higher elevation w.r.t normal lake level#56Location of DG in RAPS 1&2 for supplying power in design flood Incase of upstream dam break, normal and emergency power supplies will not be available. However additional DG was added in 1998 as an safety upgrade is located 7m above the flood level to cater emergency power requirement. ELEVATION 359.6 m, Service Building Floor ELEVATION 366.6 m, DG-5 feet DG-5 Floor#57Summary of Recommendations Made By Task Forces#58Recommendations Made By The Task Forces Present review indicate that adequate provisions exist to handle Station Blackout situation and maintaining continuous cooling of reactor core. However, to further augment the safety levels and improve defense in- depth, salient recommendations have been made like Hook up provisions for addition of water, improvement improvement in management in containment etc. Hydrogen specific Common recommendations made and additional recommendations for the TAPS 1&2, RAPS-1&2, MAPS-1&2 Standard PHWRs stations are also made and details are given in section-4 of Report "Safety Evaluation Of Indian Nuclear Power Plants Post Fukushima Incident". Recommendations for under construction plants KKNPP and 700MWe PHWRs are available in KKNPP task force report and 700 MWe task force report. N.B: More information given as links to Bold Italics.#59ACTION PLAN#60Action Plan ➤ Action plans for the recommendations have been worked out based on the information available on the event as on date. ➤ Broad road map is finalized and details are given in Section-5 of Report "Safety Evaluation of Indian Nuclear Power Plants Post Fukushima Incident". AERB is also reviewing the event. Recommendations and Action Plan is being revisited and changes, if any, will be incorporated as and when ■ Event at Fukushima further unfolds ■ ◉ Better understanding and analysis of event completes Review of international community, their findings and lessons learnt ■ Review and deliberation by AERB#61Typical Actions Planned for PHWR Reactor trip on seismic event. ➤ New switches to be procured. Procurement of diesel operated portable pumps. ➤ Specifications completed. Procurement of trolley mounted air cooled DG and switch gear. ➤ Specifications being finalized. Procurement of hoses. Procurement of miners head lamps. Provision of bore wells in operating island. ➤ Feasibility study done. Additional hook up points for various systems. ܀ ܀ ܀ * ܀ ܀#62Typical Actions Planned for PHWR A A Emergency Operating procedures (EOP) modified/prepared. The off-site emergency preparedness plans reviewed. Readiness to implement the emergency preparedness plans is verified during periodic emergency exercises. This plan is being reviewed in the backdrop of the Fukushima accident and required additions will be appended suitably.#63ACTIONS ALREADY IMPLEMENTED#64Reactor Pressure Vessel Common fill point at TAPS 1&2 Common Hook up points provided in north and south side of Reactor Building. These hook up points can be used to inject water directly to Reactor Pressure Vessel (RPV) of Unit-1&2 manually from external water source. This is in addition to existing design provision assuming loss of all sources of Power. This scheme has already been Implemented in April-2011. FROM RB (NORTH SIDE) EXTERNAL FIRE TENDER CONNECTION FOR PEACTOR PRESSURE VESSEL #188 FILL FROM RB (SOUTH SIDE) EXTERNAL FIRE TENDED CONNECTION FOR REACTOR PRESSURE SEL #182 FILLING#65Emergency Condenser Common Fill Point at TAPS 1&2 in Hook up points provided. south side of Reactor Building. These hook up points can be used to inject water directly to Emergency Condenser shell side of Unit-1&2 manually from external water source. This is in addition to existing design provision assuming loss of all sources of Power. This scheme has already been Implemented in April- 2011. EXTERNAL FIRE TENDER CONNECTION FOR EMERGENCY CONDENSER SHELL #182 FILLING 131.1 LLY STORAGE FOR av.#66Spent Fuel Pool Fill Point at TAPS 1&2 Hook up point provided in waste management Building. This hook up point can be used to inject water to spent fuel pools in Reactor Building manually from external water source. This is in addition to existing design provision assuming loss of all sources of Power. This scheme has already been Implemented in April- 2011. EXTERNAL FIRE TENCE FOR FUEL POOL 182 FILLING#67Present Scenario ➤Latest information suggests there was core melt down in units 1,2,3 of Fukushima Daiichi. ➤ Following International Reports on Fukushima events are available at NPCIL website. ■IAEA Report ▪Japanese Government report ➤Based on above information, further assessment and evaluation are being carried out.#68NPCIL Working towards Green Future Thank You