1 / 23

ANGRA 1 E 2

Session V Overview of Fukushima Response Plan by ELETRONUCLEAR Paulo Carneiro Technical Advisor Technical Directorate. NOVAS USINAS. NOVAS USINAS. ANGRA 1 E 2. ANGRA 3. Angra Nuclear Power Station. ANGRA 1 PWR Power: 640 MW Technology: Westinghouse Operation start: Jan. 1985.

adonica
Download Presentation

ANGRA 1 E 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Session V Overview of Fukushima Response Plan by ELETRONUCLEAR Paulo Carneiro Technical Advisor Technical Directorate NOVAS USINAS NOVAS USINAS ANGRA 1 E 2 ANGRA 3

  2. Angra Nuclear Power Station ANGRA 1 PWR Power: 640 MW Technology: Westinghouse Operation start: Jan. 1985 ANGRA 2 PWR Power: 1,350 MW Technology: KWU/ Siemens Operation start: Jan. 2001 ANGRA 3 PWR Power: 1,405 MW Technology: KWU/ Siemens/ Areva Under construction Planned start of operation: June 2018 (illustrative view) RADIOACTIVE WASTE STORAGE CENTER 500kV Switchyard ANGRA 2 ANGRA 1

  3. Organizational Approach to Fukushima • Working groups of specialists under guidance of a • Fukushima Response Management Committee; • gathering and evaluation of information about the accident onset, development and consequences; • identification of lessons learned applicable to Brazilian NPPs; • safety assessments; • establishment and management of an executive plan (studies and projects consolidated in the ELETRONUCLEAR Fukushima Response Plan); • participation in national and international discussionforums about the lessons learned and safety initiatives.

  4. Full Integration with Nuclear Industry Initiatives Brazilian Nuclear Authority

  5. Response to Fukushima – Main Documents Fukushima Response Plan (submitted to CNEN in December, 2011) 5-years Executive Plan 56 Initiatives, Studies and Design Modifications Estimated US$ 150 million Investments Performance of Stress Test

  6. Response to Fukushima – Main Documents STRESS TEST submitted to CNEN in April, 2012 Basis: WENRA Specification for Stress Test Report

  7. Response to Fukushima – Main Safety Goals

  8. Protection from Hazard Events External Events Earthquakes; Rainfalls; Landslides; Tidal Waves; Tornadoes. Updating of data basis; Reevaluation by up-to-date methodologies; Probabilistic approach; Verification of safety margins. Internal Events Fire; Internal Flooding. Reevaluation considering up-to-date safety requirements; Identification of design gaps. (overall safety evaluation by extended PSA under development for Angra 1, 2 and 3)

  9. Protection from Hazard Events - Results Earthquakes • preliminary seismic reevaluation according to EPRI Report 1025287; • Angra characteirzed as “low seismicity site”; no special requirement for further evaluations; • estimated safety margins of 2.5 for Angra 1 and 3.0 for Angra 2; • ongoing extensive updating of geological and seismological database (three-years program); • preliminary GMRS determined for consideration in the Seismic PSA (results up to end 2015). Low seismicity site Largest earthquake 5.2 mb at 250 km (PGA 0.002g at site) Design PGA 0.10g (p< 10-4/yr)

  10. Protection from Hazard Events - Results Rainfalls and Landslides • Studies considering heavy rains and seismic induced landslides concluded; extreme case of full rupture of slope covering material evaluated. • Switchyard and discharge channels may be affected however no impact on Plants buildings; • Recommendation for enlargement of slope drainage system and reinforcement of some stabilization works (implementation planned to start until end of 2014); Slopes very steep around the site Residual and colluvial soils High rainfall rates Station protected by slope stabilization works and slope monitoring system

  11. Protection from Hazard Events - Results Rainfalls and External Flooding plant construction level Angra 1 and 2 access to safety buildings • Reevaluation of flooding level under more severe conditions concluded (rainfall rate higher than 10,000 years rainfall, blockage of site drainage channels and circulating water discharge tunnel due to landslides); • Current design flooding level includes sufficient safety margin (up to 75.000 years rainfall); checking and reinforcement of existing flooding barriers. + 5.60m + 5.15m 0 CNG

  12. Protection from Hazard Events - Results Tidal Waves • calculation of tidal waves for severe metereological conditions at Ilha Grande Bay; • evaluation of jetty stability through physical model; • expected recommendation of jetty strucutral reinforcement. Angra NP Station Bay area, natural protection from Atlantic Ocean Ilha Grande Bay

  13. Protection from Hazard Events - Results Tornadoes • Tornadoes were not originally considered for Angra 1 and 2 due to low probability (~10-7/y); • Tornado hazard study developed for Angra 3; • Impact on Angra 1 and 2 evaluated and actions plans issued for further evaluation and/or protection of selected structures and components. Fire Hazard of Angra 1 revised by EPR (risk based evaluation); design modification packages under evaluation. Internal Fire Internal Flooding Reevaluation of Angra 1 design against internal flloding; final report expected for September 2014.

  14. Reevaluation of Cooling Capacity under BDBE STRESS TEST REPORT (deterministic approach, no credit given to special design features or conditions at Angra site) • Event Initial Conditions • Loss of Offsite and Onsite Power (SBO) and Loss of Ultimate Heat Sink (LUHS) • no possibility of external support within 72h after the accident onset; • Plant in Power Operation • 100% reactor power; • Plant at Refueling (worst condition for fuel pool temperature) • full core transferred to fuel pool; • full utilization of fuel pool storage racks;

  15. Evaluation of Station Blackout Scenarios (SBO) 2x 4x M M G G M M M G G G 4x 2x M M M G G G M M M G G G Favorable power supply conditions in Angra 1 and Angra 2 Cachoeira Cachoeira São São Zona Zona Santa Santa Paulista Paulista Jos Jos é é Oeste Oeste Cruz Cruz SE SE SE SE “ “ Off Off - - Site Site 500kV 500kV 138kV 138kV Power Power ” ” Very conservative approach of considering loss of all AC power A2 A1 A2 A1 A2 A1 A2 A1 Angra 2 Angra 1 2 x 100% 2 x 100% 4 x 50% 4 x 50% normal design condition(2 diesel groups per reactor) 2x 2x 1st Emergency Power System 4x 4x M M G G M M G G EDE EDE – – 3/4 3/4 UBP UBP – – D1 D1 special design conditions for Angra 1 and 2 (12 diesel groups for 2 reactors !!!) 4x 4x 2x 2x 2ndEmergency Power System M M G G M M G G ULB ULB – – D2 D2 EAS EAS – – 1A/1B 1A/1B both meet NRC requirements for exclusion of SBO 2,5h 2,5h 4,0h 4,0h

  16. Evaluation of Station Blackout Scenarios (SBO) • possibility of SG feeding through mechanically driven pumps (Auxiliary Feedwater Turbine Pump AF-2 in Angra 1 and Diesel Driven Emergency Feedwater Pumps LAS in Angra 2); • at least 20 hours in Angra 1 and 33 hours in Angra 2 of feeding from, respectively, Auxiliary Feedwater Tank - AFT and Demineralized Water Pools - DWP; • possibility of AFT and DWP refilling from Fire Fighting Water Supply System - FFWS (5,000 m3 reservoir, located on an elevation 110 m above the site grade); • possibility of full passive secondary B&F from the FFWS reservoir (connection before SG becomes empty, in case AF-2 or LAS pump fails, about 50 minutes).

  17. Evaluation of Loss of Heat Sink Condition • Very conservative approach: • water intake structures in area of protected sea water (Ilha Grande Bay); • water intake structures protected by jetty 8.0 m high above average seawater level; • very low probability of water intake blockage to the extent of impairing minimum flow for residual heat removal; • Main implications for the plants: • failure of both Emergency Supply Diesel Generator Systems in Angra 1 (bunkered Emergency Feedwater Diesels in Angra 2 not dependent on Service Water); • impossibility of operating the RHR chain.

  18. Overview of Additional Emergency Supply Alternatives RF435: Mobile DG (Emergency Power Supply for essentialSafety Systems) RF435: Mobile DG (Emergency Power Supply for essentialSafety Systems) RF431: InterconnectionofEmergency Power Busbars Angra 1 and 2 (use of DG reserve capacity) RF411: Cross-tieofEmergency Power Busbars RF421: Interconnectionof Diesel Systems D1 and D2 RF413: alternativecoolingchain for Emergency Power DG ANGRA 1 ANGRA 2 RF422: Mobile DG (extensionofbatteriesautonomy) RF412: Mobile DG (extensionofbatteriesautonomy) under evaluation RF433: SmallHidropower Unit atMambucaba River

  19. Additional Alternatives for Reactor Cooling Alternatives for Reactor Cooling Via Steam Generators • Design Criteria (based on FLEX-approach); • Description of Cooling Alternatives; • Basic Design.

  20. Additional Alternatives for Reactor Cooling Mobile Pumps for SG Feeding Mobile Pumps for Refilling Water Reservoirs Mobile Ar Compressor for Remote Valve Actuation (Angra 1) Fire Hoses

  21. Loss of Fuel Pool Cooling Fuel Pool Temperature Increase after Loss of Cooling (*) limit condition, full core unloaded and full occupation of pool racks • Improvements in design phase: • Angra 1: external mobile coolingunit (Westinghousesolution for similar plants); • Angra 2: fuel pool coolingandrestoringof RHR chainusingfirefightingwater (AREVA solution for similar plants)

  22. Mitigation of Radiological Consequences Containment Protection: passive H2 catalytic recombiners already installed in Angra 1 and 2 filtered containment venting under design for Angra 1 and 2 • Severe Accident Management Guidelines (SAMGs): • pre-Fukushima WOG SAMGs are in the final process of validation, integration with the Emergency planning procedures and training in Angra 1; • post-Fukushima AREVA SAMGs in the final process of validation, integration with the Emergency planning procedures and training in Angra 2; (other improvements in the infrastructure for emergency planning are being planned and performed).

  23. Thanks for theattention!!! paucar@eletronuclear.gov.br

More Related