Japanese Nuclear Accident And U.S. Response. Ellen Anderson Senior Project Manager Radiation Safety & Environmental Protection May 20, 2011

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1 Japanese Nuclear Accident And U.S. Response Ellen Anderson Senior Project Manager Radiation Safety & Environmental Protection May 20, 2011

2 Overview Introduction to NEI Fukushima Daiichi The Events Environmental Release Protective Actions U.S. Response NRC NEI Industry environmental sampling

3 Nuclear Energy Institute The Nuclear Energy Institute is the industry s policy organization. Its broad mission is to foster the beneficial uses of nuclear technology in its many forms. Accomplishing the Mission Advocacy and representation before the Congress, Executive Branch agencies, regulatory bodies, the courts, media and state policy agencies 3

4 350 Member Companies in 19 Countries 4

5 NEI Divisions Communications Nuclear Generation Member Relations and Corporate Services Policy Development Governmental Affairs Legal 5

6 Nuclear Generation Scope of Work Facilitate a safety-focused, performancebased regulatory framework Manage the NRC interface for existing plants on significant generic regulatory issues Support the licensing and deployment of new nuclear power plants 6

7 Nuclear Energy in Japan 54 operating nuclear reactors (49 gigawatts) Two nuclear plants under construction Tokyo Electric Power Co. produces 27% of Japan s electricity

8 Fukushima Daiichi Nuclear Power Plant Before the Accident Units 5, 6 Unit 2 Unit 1 Unit 3 Unit 4 At the time of the earthquake Reactors 1, 2 and 3 operating Reactors 4, 5 and 6 shutdown for maintenance, inspection, refueling

9 Fukushima Daiichi Nuclear Station Six BWR units at the Fukushima Nuclear Station: Unit 1: 439 MWe BWR, 1971 (unit was in operation prior to event) Unit 2: 760 MWe BWR, 1974 (unit was in operation prior to event) Unit 3: 760 MWe BWR, 1976 (unit was in operation prior to event) Unit 4: 760 MWe BWR, 1978 (unit was in outage prior to event) Unit 5: 760 MWe BWR, 1978 (unit was in outage prior to event) Unit 6: 1067 MWe BWR, 1979 (unit was in outage prior to event) 9

10 Event Initiation The Fukushima nuclear facilities were damaged in a magnitude 9.0 earthquake on March 11 th (00:46 EST), centered offshore of the Sendai region, which contains the capital Tokyo. Plant designed for magnitude 8.2 earthquake. Serious secondary effects followed including a significant tsunami, significant aftershocks and a major fire at a fossil fuel installation. 10

11 Webcam Picture of Tsunami Hitting Fukushima Daiichi Nuclear Station on March 11, 2011

12 Tsunami Damage Looking Toward the Nuclear Plant

13 Fukushima Daiichi Unit 1 13

14 Initial Response Nuclear reactors were shutdown automatically. Within seconds the control rods were inserted into core and nuclear chain reaction stopped. Cooling systems were placed in operation to remove the residual heat. The residual heat load is about 3% of the heat load under normal operating conditions. Earthquake resulted in the loss of offsite power which is the normal supply to plant. Emergency Diesel Generators started and powered station emergency cooling systems. One hour later, the station was struck by the tsunami. The tsunami was larger than what the plant was designed for. The tsunami took out all multiple sets of the backup Emergency Diesel generators. Reactor operators were able to utilize emergency battery power to provide power for cooling the core for 8 hours. Operators followed abnormal operating procedures and emergency operating procedures. 14

15 Loss of Makeup Unit 1 Offsite power could not be restored and delays occurred obtaining and connecting portable generators. After the batteries ran out, residual heat could not be carried away any more. Reactor temperatures increased and water levels in the reactor decreased, eventually uncovering and overheating the core. Hydrogen was produced from metal-water reactions in the reactor. Operators vented the reactor to relieve steam pressure - energy (and hydrogen) was released into the primary containment (drywell) causing primary containment temperatures and pressures to increase. Operators took actions to vent the primary containment to control containment pressure and hydrogen levels. Required to protect the primary containment from failure. Primary Containment venting is through a filtered path that travels through duct work in the secondary containment to an elevated release point on the refuel floor (on top of the reactor building). A hydrogen detonation subsequently occurred while venting the secondary containment on March 12 th (06:20 EDT). Occurred shortly after an aftershock at the station. Spark likely ignited hydrogen. 15

16 Hydrogen Detonation at Unit 1 Refuel Floor Reactor Building 16

17 Mitigating Actions Unit 1 The station was able to deploy portable generators and utilize a portable pump to inject sea water into the reactor and primary containment. Station was successful in flooding the primary containment to cool the reactor vessel and debris that may have been released into the primary containment. Boric acid was added to the seawater used for injection. Boric acid is liquid control rod. The boron captures neutrons and speeds up the cooling down of the core. Boron also reduces the release of iodine by buffering the containment water ph. Containment Flooding Effects 17

18 Emergency Response Unit 2 Safety relief values failed closed, increased pressure blocks seawater injection by fire pumps, uncovering fuel on March 14 th (by 11:00 EDT) Reactor building blowout panel opened to avoid hydrogen explosion post venting. JAEA reports explosion on March 15 th (17:14 EDT) near suppression pool tube following the total uncovering of the fuel in core. Primary containment pressure drops to atmospheric causing speculation that containment is compromised. Seawater injection at 1.4 tons/minute by March 16 th (0:400 EDT) determined to be sufficient to remove decay heat. 18

19 Unit 2

20 Emergency Response Unit 3 On March 13 th (02:00 EST) the RCIC shutdown when DC power was expended, uncovering some amount of the core. Seawater injection commenced along with periodic venting of containment. On March 13 th (10:01 EST) a hydrogen explosion injures some personnel and causes significant damage to secondary containment. The reactor status listed as stable with continuing seawater injection on March 15 th (10:00 EDT) Control room evacuated on March 15 th (21:45) based on concern that Unit 3 containment was breached. Staff returned 45 minutes later. Seawater pumped by fire engines at 1.4 tons per minute, sufficient to remove decay heat, by March 16 th (04:00 EDT) White smoke (large flume) observed. Causes not identified by boiling fuel pool or steam leak from containment suspected. Helicopters used to add water to fuel pool beginning March 16 th (20:48 EDT) High impact water cannon utilized to spray fuel pool to increase pool inventory. Unit 3 reactor water level is stabilized and seawater injection being maintained. 20

21 Unit 3

22 Emergency Response Unit 4 Very load sound/explosion noted in reactor building on March 14 th (17:00 EDT) deforming wall and roof panels. Speculated but not confirmed that fuel pool may have overheated leading to hydrogen release/explosion. At same time, radiation levels significantly increase on site. Fire occurred in the NW corner of the reactor building on March 14 th (20:38 EDT). The fire self-extinguishes. By March 15 th (06:58) spent fuel cooling unavailable. Second fire in same area observed and self extinguishes. Using high power spray pump to inject water on the operating floor to cool unit 4 fuel pool. 22

23 Units 3 & 4

24 Unit 4 Refuel Bridge

25 Big Picture Equivalent of General Emergency declared to the event at Unit 1. Control rooms at units 1, 2, and 3 evacuated due to radiation levels. Radiation levels between 3.2 and 40 Rem/hr in vicinity of units 1-4. March 14 th (22:30 EDT) 800 workers temporarily evacuated from site. Evacuation of public performed within 20 km (13 miles) of plant; approximately 200,000 people evacuated. Several fatalities occurred at the station along with numerous injured workers. Authorities distributed Potassium-iodide tablets to protect the public from potential health effects of radioactive isotopes of iodine that could potentially be released. This is quickly taken up by the body and its presence prevents the take-up of iodine-131 should people be exposed to it. Over 300 after shocks have occurred and continue to challenge station response. 25

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30 Protective Actions 3/11 Evacuation ordered within 3 km (1.8 miles) Remain indoors with in 10 km (6.2 miles) 0544hrs Evacuation within 10 km 1825hrs Evacuation within 20 km (12.5 miles) 3/25 Population should consider leaving from km ( miles)

31 Protective Actions - continued 4/21 No Entry Zone Established within 20 km (12.5 mile) radius 4/22 20 km evacuation zone is expanded to include the area where annual radiation exposure is expected to be > 20 msv (2 rem) People in the expanded zone are ordered to evacuate within a month or so. 31

32 Protective Actions - continued People living in the km area and other areas are asked to prepare for staying indoors or evacuate should an emergency occur. 32

33 U.S. Response NRC: dispatched a response team to Japan recommended that U.S. citizens evacuate within the 50-mile radius of Fukushima Daiichi established a task force to evaluated lessonslearned as a result of the event.

34 U.S. Response Nuclear Energy Institute: Established an Emergency Response Center Industry focal point for communications Coordinated response with INPO/EPRI/WANO Coordinated response with NRC/EPA/OSTP/CRCPD Interfaced with the media significant support from industry executives Development of communication tools Dedicated webpage Continuous updates to members Established a web-based platform to report results of U.S. voluntary supplemental environmental samples

35 U.S. Industry Response Ensure Safety at Nuclear Power Plants The U.S. nuclear energy industry commenced an assessment of the events in Japan and is taking steps to ensure that U.S. reactors could respond to events that may challenge safe operation of the facilities. These actions include: Verify each plant's capability to manage major challenges, such as aircraft impacts and losses of large areas of the plant due to natural events, fires or explosions. Verify each plant's capability to manage a total loss of off-site power. Verify the capability to mitigate flooding and the impact of floods on systems inside and outside the plant. Perform walk-downs and inspection of important equipment needed to respond successfully to extreme events like fires and floods. In addition, INPO is acting as a collection point for emergency response materials being donated by the U.S. nuclear industry.. 35

36 U.S. Environmental Data 3/17 Radiation detectors at O Hare identify contamination on luggage and ventilation system from plane originating from Japan 3/18 SONGS (CA) identifies an air sample containing 6.00E-13uCi/cc I-131 3/19 Diablo Canyon (CA) sees 5.64E-13uCi/cc I /21 Several sites identify 6-7E-13uCi/cc Cs-137 Most, if not all U.S. plants have identified low levels of I-131 and Cs-137

37 U.S. Environmental Data 3/29 NEI launched the Fukushima Environmental Data Collection System Website available to NRC, EPA, INPO, EPRI, ANI and CRCPD Approximately 2000 data points have been placed on the website. Since April 8 th, U.S. plants have reported less than detectable readings Highest environmental reading recorded on the website was a rain water sample at 10.2 miles from the Diablo Canyon NPP (CA) on 3/ pci/l

38 U.S. Industry s Response U.S. Radiation Protection Managers: Met on April 4, 2011 and identified equipment, procedures/processes and personnel issues that could affect U.S. nuclear power plants in a severe accident similar to Fukushima Daiichi Will assess, prioritize and implement changes as necessary

39 Status of Fukushima Daiichi Nuclear Plant (May 2011) Unit 1 Hydrogen explosion, fuel damage, seawater cooling the reactor vessel, status of spent fuel pool unclear Unit 2 Fuel damage, seawater cooling the reactor vessel, cooling water restored to spent fuel pool Unit 3 Hydrogen explosion, fuel damage, seawater cooling the reactor vessel, water sprayed into spent fuel pool Unit 4 Reactor core offloaded, fire and possible hydrogen explosion, damage to spent fuel in fuel pool Units 5 and 6 Stable with power and cooling water circulation restored

40 Emergency Planning for U.S. Nuclear Energy Facilities 10-mile emergency planning zone (evacuation or sheltering); 50-mile monitoring zone for environment and food. Radiation monitoring by plant site, Nuclear Regulatory Commission (NRC) and state and local personnel from the site and surrounding areas Decisions on public precautionary measures made by state or local authorities based on recommendations from plant operator and NRC Emergency plan exercises in coordination with state, local, and federal officials, evaluated by the NRC and FEMA

41 Information Sources Nuclear Energy Institute ( U.S. Nuclear Regulatory Commission ( U.S. Department of Energy ( International Atomic Energy Agency ( American Nuclear Society ( Health Physics Society ( Japanese Nuclear and Industrial Safety Agency ( Japan Atomic Industrial Forum ( Tokyo Electric Power Company (

42 Backup Slides

43 Fukushima Nuclear Workers In the media: Fukushima Fifty NY Times: Day Laborers Brave Risks at Japan s Nuclear Plants Asia Pacific Journal: Dying For TEPCO? Fukushima s Contract Workers ScienceInsider: Should Japan Bank Stem Cells From Fukushima Nuclear Workers? The Japan Times: Worker Found Overexposed to Radiation Etc

44 Fukushima Nuclear Workers Japan Radiation Dose Limits: Occupational dose limit: 50 msv (5 rem) in one year and no more than 100 msv (10 rem) over five years. Emergency dose limit: 100 msv (10 rem) Revised for the Fukushima Accident (Special Measure) on 15 March 2011: 250 msv (25 rem) Legal effective dose limit for females - 5mSv (500 mrem) over 3 months even in an emergency situation Extremity dose limit msv (50 rem) in a year

45 Fukushima Nuclear Workers As of April 28, 2011: workers (est. 27 TEPCO, 3 Contractor) >100 msv (10 rem) 2 workers exposed to >170 msv (17 rem) on 24 March laying cables in unit 3 basement. WB dose < legal limit but dose to legs and feet far beyond the limit for extremities.

46 Fukushima Nuclear Workers Maximum external whole body exposure is: msv (20.18 rem) Maximum internal exposure is: 39 msv (3.9 rem) Maximum combined dose is: msv (24.08 rem)

47 Fukushima Female Nuclear Workers 2 Female Employees Exceeded Japan Regulatory Limit Employee A: msv (1.7 rem) Internal: msv (1.36 rem) External: 3.95 msv (0.395 rem) Employee B: 7.49 msv (0.75 rem) Internal: 6.71 msv (0.671 rem) External: 0.78 msv (0.078 rem) Medical assessment indicates no impact on health

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