Preparedness at PFBR Kalpakkam to meet the challenges due to Natural events Prabhat Kumar, Project Director, PFBR, Director construction BHAVINI

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1 BHARATIYA NABHIKIYA VIDYUT NIGAM LIMITED (A Government of India Enterprise) Preparedness at PFBR Kalpakkam to meet the challenges due to Natural events Prabhat Kumar, Project Director, PFBR, Director construction BHAVINI

2 PFBR REACTOR ASSEMBLY Item 1 Main Vessel 2 Core Support Structure 3 Core Catcher 4 Grid Plate 5 Core 6 Inner vessel 7 Roof slab 8 Large Rotatable Plug 9 Small Rotatable Plug 10 Control Plug 11 Absorber Rod Drive Mechanism 12 Transfer Arm 13 Intermediate Heat Exchanger 14 Primary Sodium Pump 15 Safety Vessel 16 Reactor Vault

3 PFBR Details No. of fuel Assemblies : 181 No. of pins in one Sub Assembly : :217 Refueling interval Pu enrichment Zone I/II Rx Coolant inlet /outlet : 185 EFPD : 20.7 / 27.7 wt % : 397 / 547 ºC Steam Temp. / Pressure : 490 ºC / 167 Kg/Cm 2

4 PFBR Flow Sheet

5 PFBR PFBR is being constructed near the coast of Bay of Bengal. Task Force has been constituted to review the issues related to the: safety of reactor, spent fuel storage facility Multiunit site and other related issues arising due to natural events.

6 Issues Public perception is very low Equipment failure Human error Matural Event

7 Public is affected Livelyhood Fear of new issue: Design? QA? Materials? Manufacturing? Terrorism? Insider Threat?-Even operator must not be able to damage the core

8 Public is not concerned of source of electricity- Several decades of effort of nuclear technology development is at risk if we can not win public confidence

9 Site Coastel- What if flooded due to cyclone Height of water during tsunami Effect of splash due to tsunami; Equipment Drainage

10 To be taken care Reactor Shutdown, maintaining core cooling and containment integrity Gravity drop Cooling in every scenario: Operational Grade Decay Heat Removal (OGDHR) 4 loops are provided, each loop having capacity of 8 MWTh. (Total decay heat 20 MWTh)

11 Safety assessment of external events leading to BDBA conditions to review and address the following parameters / issues : Capability for reactor shut down, maintaining shut down condition and core cooling Capability to maintain containment integrity under credible BDBA conditions

12 Review of DBA and BDBA conditions to assess the strengthening / upgradation of the systems required to ensure the containment integrity. Provision of reactor trip on seismic event

13 Guard pipe is provided around primary sodium piping Leak collection trays are provided for the secondary sodium piping. All pipe lines are of welded construction- No valves in primary main circuit Sodium fire fighting system is established

14 Support Systems Alernate Battery bank Spares Obstruction clearence Communication Large scale public movement Shelters

15 Storage of large quantity of Sodium in the Primary and Secondary systems Whether SGB could get flooded Can Sea water enter and affect the SS Whether fire fighting system is adequate Whether Cables have joints that can get affected Whether Adequate diesel supply can be ensured Water sources Can servive water, raw water and DM water get affected due to sea water ingress?

16 Spent fuel Storage Review of the spent fuel storage pool for seismic event higher than the design value. Review of possible cracks due to higher seismic, possible pipe line failure and provisions to make up the water level. Review of any possible fall of heavy object on storage pool during the seismic event.

17 Spent fuel Storage Spent fuel is kept in the spent fuel storage location in the reactor core for about two cycles. Hence decay heat of the spent fuel will be less when it is removed for storage in spent fuel storage pool. 45,000 Litres capacity demineralised water storage tank installed in the Fuel Building can supply water to spent fuel storage bay in case of failure of normal source. Yet provision planned for additional cooning facility

18 Effect on Spent Fuel and Fresh Fuel assemblies storage facilities to remain intact Analysis Water supply possibility

19 Availability of Diesel Generator beyond design basis scenario Possibility of hooking up back-up power supply system in the event of plant Diesel Generator unavailable Availability of Emergency Diesel Generators on wheel/ provision of backup power supply- Levels and Roads

20 Accident management strategy Emergency preparedness Emergency Crew Adequacy of the approaches to the plant site to handle emergency scenarios Accident management (site & off site-ndma, NDRF)

21 Preliminary review has indicated that we donot have much concern- many concerns were addressed after 2004 tsunami

22 PFBR plant is designed to be safe in all natural eventualities such as tsunami, earthquake, cyclone & flood. Kalpakkam comes in Seismic Category Zone III as per the seismic classification.

23 For PFBR, the Design Basis Flood Level is fixed as 6.45 metres above Mean Sea Level (MSL) based on 1000 years return period During the worst ever Tsunami that stuck Kalpakkam in Dec. 2004, the maximum water level rise was 4.71 metres above MSL.

24 After the Tsunami at Kalpakkam in Dec. 2004, shore protection and Tsunami bund made out of engineered boulders stacked at a height of 5.4 Meters above MSL was erected for breaking the intensity of sea waves during tsunami.

25 Shore protection Tsunami bund 25

26 The finished floor level of Safety related Buildings are at metres above Mean Sea Level (MSL) :

27 The finished floor levels of Safety related Buildings are 3.15 metres above Design Basis Flood Level (6.45M)and 4.9 metres above the maximum water level rise observed during Tsunami in Dec (4.71 M)) Hence operation of Emergency Diesel Generators, reactor safe shut down & cooling and spent fuel cooling will not be affected during a design basis Tsunami event.

28 Hydrogen Issue In PFBR water is not used as the coolant for reactor. This precludes any possibility of hydrogen generation/explosion in RCB. Fuel clad material is not Zirconium (it is Alloy D-9 an alloy of Cr, Ni, Mo, Ti & Si). Hence no metal water reaction & hydrogen generation in Spent fuel storage facility in case loss of cooling. However Hydrogen due to BSC water and sodium need to be studied

29 Emergency Diesel Power PFBR is provided with four diesel generators Two are sufficient to meet the station requirement All four DGs are in separate buildings 2 are in east. Remaining 2 are in the west side of Main plant building, away from sea side. Located at meters above MSL

30 An in-depth study by the Task Force is in progress to review & identify any weakness Based on the review and recommendations of Task Force, modifications will be carried out to address these issues.

31 Erection of steam generator

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34 Mock up work completed as per the guide lines of PDSC. Welding commenced

35 Sea water Intake 1. Sinking of caisson has reached beyond soft rock region. 2. Concreting of caisson completed for 12 m depth from cutting edge. 3. Inside caisson chiseling and grabbing work is in progress. 4. On top of jetty pipe line pedestal work is in progress.

36 Major TG equipment's at site Around 4000 Tons of material reached site in TG package

37 Thank you