THE FUKUSHIMA ACCIDENT: CAUSES, RESULTS AND IMPLICATIONS FOR EUROPE

Transcription

1 THE FUKUSHIMA ACCIDENT: CAUSES, RESULTS AND IMPLICATIONS FOR EUROPE Steven C. Sholly, Senior Scientist Institute of Safety and Risk Sciences Department of Water, Atmosphere & Environment University of Natural Resources & Life Sciences Course (Winter 2011) 10 Oct-11 Lecture 1: Introduction & Background to 1

2 Introduction 2

3 My Background Steven C. Sholly, Senior Scientist, Institute of Safety & Risk Sciences. Expatriate American citizen, resident of Vienna since 1998 B.S. in Education, years of experience in deterministic & probabilistic safety assessment (PSA), safety analylsis and environmental impact assessment (EIA) of nuclear and chemical facilities. Member of IAEA Nuclear Safety Standards Committee (NUSSC) since Consultant to Austrian government (UBA & BMLFUW) on numerous occasions since Accident analyst for DOE EIA s of Rocky Flats & Los Alamos National Laboratory. 3

4 Course Rationale 1 On 11 March 2011, the Tōhoku megathrust earthquake (9.0 M W ) struck in the Pacific Ocean 72 km east of the Oshika Peninsula & 180 km from Fukushima Daiichi (lasting 6 minutes). There was an M W 7.2 foreshock about 40 km from the 11 March epicenter on 9 March Following the main shock, there were a number of large aftershocks, including M W quakes of 7.9 (29 minutes after the main shock) and 7.1 ten minutes after that. 4

5 Course Rationale 2 Fukushima Daiichi Units 1, 2 & 3 automatically shut down (scrammed) as designed at 0.138g PGA early during the main shock (Units 4, 5 & 6 were already in outages at the time). The earthquake (one of the five largest in recorded history) produced tsunami waves that reached the Fukushima Daiichi nuclear power plant less than an hour later. 5

6 Course Rationale 3 Although the Fukushima Daiichi plant survived the earthquake with minor damage and a loss of offsite power, the tsunami that struck the plant caused the failure of all but one diesel generator, resulting in station blackout for Units 1-4, and also resulted in Units 5 & 6 sharing the one remaining air-cooled diesel generator. This lecture course will examine the resulting accidents in detail, and explore the implications of the Fukushima accidents for nuclear power plants in Europe as well as advanced nuclear power plant designs. 6

7 Tsunami Wave Topping Seawall Tsunami wave topping the 5.7 meter high seawall at Fukushima Daiichi on 11 March 2011, in front of the two diesel generator fuel tanks. [Source: TEPCO Photo] 7

8 Tsunami Wave Topping Seawall Tsunami wave topping the 5.7 meter high seawall at Fukushima Daiichi on 11 March 2011, in front of the seawater pumps. [Source: TEPCO Photo] 8

9 Course Requirements 9

10 Course Requirements 1 The Lecture Course is open to all students. Lecture attendance is a requirement. Attendance at lectures will account for 50% of your grade. There will be Lecture Sessions 10 October, 24 October, 7 November, 21 November (needing an alternate, either 14 November or 28 November perhaps), 5 December, and 2 January. There will be Sessions on 16 January and 30 January at which presentations by lecture participants will be made and discussed (and at which attendance is also a requirement). 10

11 Course Requirements 2 Electronic copies of lecture viewgraphs will be available to class participants either at the lecture or on the following Monday by . Obtaining the viewgraphs is not a substitute for attending the lecture. Lecture participants are responsible for material covered in the viewgraphs as well as that covered orally and visually in the lectures. If you miss a lecture: (1) contact me for the viewgraphs; and (2) discuss the lecture with me and/or one or more classmates so you know what was covered orally and visually in the lectures. 11

12 Course Requirements 3 All lecture participants will make a 15- minute presentation, the quality of which represents 30% of your grade. A copy of your presentation must be submitted electronically to me not later than the day of the presentation. The topics of the presentations will be related to some aspect of the Fukushima accidents, to be proposed by the class participants and agreed to with me not later 5 December. 26-Aug-11 Lecture 1: Introduction to Course, Fukushima Précis 12

13 Course Requirements 4 There will be two examinations ("quizzes") covering materials presented in the lectures. The quizzes will account for 20% of your grade. The quizzes will take place in the Weeks of 7 November and 5 December. The quizzes will consist of multiple choice questions. The purpose of the quizzes is to ensure that you have understood the basic points presented. 13

14 Fukushima: Before the Accidents 14

15 Before the Accidents 1 Fukushima is a prefecture of Japan in the Tohoku region of the island of Honshu (Miyagi & Iwate prefectures are to the north; Ibaraki, Tochigi & Chiba are to the south). Fukushima city is the capital of the prefecture. The population of Fukushima prefecture is about 2.13 million persons. The Fukushima Daiichi nuclear plant includes six boiling water reactors, a common spent fuel storage facility, a radioactive waste processing facility, and various other associated buildings. 15

16 Before the Accidents 2 Tokyo Electric Power Company (TEPCO), the largest Japanese utility and the 4 th largest in the world, is the owner & operator of the Fukushima Daiichi nuclear station. 16

17 Before the Accidents 3 In 2002, the Japanese government revealed that TEPCO was guilty of filing false reports, and all seventeen of TEPCO's nuclear units (Fukushima Daiichi 1-6, Fukushima Daini 1-4 & Kashiwazaki- Kariwa 1-7) were shut down for inspection. In addition, TEPCO's Chairman, President, Vice- President, and two key advisers resigned. In July 2007, the 6.6 M W Chūetsu earthquake resulted in the shutdown of the Kashiwazaki-Kariwa nuclear station on Japan's west coast, only 19 km from the quake's epicenter. (There was no tsunami in this case.) (Units 2-4 have still not yet been restarted as of August 2011.) 17

18 Before the Accidents 4 Internal event PSAs were performed for accidents during power operation. Fukushima Daiichi Unit 4 was shut down on 29 November 2010, and subsequently defueled. All Unit 4 fuel was placed in the spent fuel pool. Unit 5 was shut down for inspection & planned maintenance on 3 January Unit 6 was shut down for inspection & planned on 14 August There were 6,415 people on site (5,500 were contractors). 18

19 Food for Thought "Human judges can show mercy. But against the laws of nature, there is no appeal." Sir Arthur C. Clarke ( , science fiction author & inventor) 19

20 Japan's Northeast Coast Nuclear Facilities Fukushima Daiichi is a 3.5 km 2 nuclear power station consisting of six units General Electric (GE) boiling water reactors (BWRs). Unit 1 is a 460 MWe BWR/3 Mark I design. Units 2-5 are 784 MWe BWR/4 Mark I units. Unit 6 is an 1100 MWe BWR/5 Mark II unit. The Onagawa (3 BWRs) nuclear station is 120 km to the north, and Higashidori (1 BWR) is farther north). The Fukushima Daini nuclear station (4 BWRs) is 11.5 km to the south, and Tokai (1 BWR) is farther south). The Rokkasho reprocessing plant, under construction, is also in the region. 20

21 BWR Basics 21

22 BWR Basics 1 As illustrated on the next slide, in a BWR light water coolant is directly boiled in the reactor vessel and sent to the turbine to produce electricity. The GE BWR employs demineralized water as a coolant and neutron moderator. The water flows upward through the core, boiling due to energy deposited in the water from the core which is at power. The coolant as it exits the core is about 12-15% saturated steam. 22

23 BWR Schematic 23

24 BWR Basics 2 The saturated steam exits the reactor core and goes through steam separators and then through steam dryers. The steam leaves the reactor pressure vessel through the vessel in four main steam lines to the turbine. Water separated from the steam is returned to the downcomer area which is separated from the reactor core area by the core shroud. 10-Oct-11 Lecture 1: Introduction & Background to 24

25 BWR Basics 3 The principal safety systems of these BWRs are: The steam-driven Reactor Core Isolation Cooling (RCIC) for emergency cooling at high pressure (except Unit 1 has an isolation condenser or IC for this purposes instead of RCIC). The steam-driven High Pressure Coolant Injection (HPCI) system for the same purpose. The motor-driven Low Pressure Core Spray (LPCS) system for emergency cooling at low pressure. The motor-driven Low Pressure Coolant Injection (LPCI) system for the same purpose. The motor-driven Residual Heat Removal (RHR) system, which removes heat from the reactor or the suppression pool and transfers it to the ultimate heat sink. 10-Oct-11 Lecture 1: Introduction & Background to 25

26 BWR Basics 4 The principal safety systems of these BWRs are (continued): RHR is an operating mode of the LPCI system. LPCI can also be used to spray water into the drywell atmosphere and into the air space above the suppression pool. The suppression pool is used to condense steam from the drywell and from the main steam lines, and also serves as a source of water for the RCIC, HPCI, LPCS, and LPCI when the condensate storage tank inventory is depleted. The next slide shows two General Arrangement drawings of Fukushima Unit Oct-11 Lecture 1: Introduction & Background to 26

27 Fukushima Unit 1 General Arrangement Drawing Note the Isolation Condensers on Section A-A at 31 meters above grade. Note also the location of the Spent Fuel Pool on Section B-B beginning at 23.1 meters above grade. 27

28 BWR Basics 5 The principal safety systems of these BWRs are (continued): Emergency diesel generators (EDGs) to supply electric power to plant systems when offsite power is not available. There are 10 water-cooled EDGs and 3 air-cooled EDGs at Fukushima Daiichi. Units 1, 3 & 5 have 2 water-cooled EDGs each. Units 2 & 4 each have 1 water-cooled EDG and 1 air-cooled EDG. Unit 6 has 2 water-cooled EDGs and 1 air-cooled EDG. The water-cooled EDGs are in the turbine hall basements; the air-cooled EDGs are behind the reactor building (Units 2 & 4) or in the reactor building (Unit 6). 10-Oct-11 Lecture 1: Introduction & Background to 28

29 BWR Basics 6 The principal safety systems of these BWRs are (continued): The Seawater Cooling System cools the water-cooled EDGs, the RHR heat exchangers, and other important systems. The primary containments at Units 1-5 consist of a pear-shaped drywell (containing the reactor pressure vessel) and a donut-shaped torus (containing the suppression pool). The torus is connected to the drywell by a series of vent pipes, which connect to a common header from which downcomers extend below the water surface. 10-Oct-11 Lecture 1: Introduction & Background to 29

30 BWR Mark I Containment 30

31 BWR Basics 7 The drywell is a steel shell (30 mm thick) backed in most areas by nearly two meters of reinforced concrete. The exceptions are the closure head at the top, the drywell vents leading to the torus, personnel and equipment hatches, and piping & electrical penetrations. There is one double door personnel airlock and two larger bolted equipment hatches provided for drywell access. 10-Oct-11 Lecture 1: Introduction & Background to 31

32 BWR Basics 8 The drywell closure head is constructed with a "double tongue and groove seal". Bolts secure the drywell head to the cylindrical section of the drywell. Shielding over the top of the closure head is provided by removable reinforced concrete shield plugs. The wetwell (torus) is not backed by reinforced concrete; it is strictly a steel structure. Access to the suppression chamber is provided by two manways with double gasketed bolted covers. 10-Oct-11 Lecture 1: Introduction & Background to 32

33 BWR Basics 9 The secondary containment surrounds the primary containment with a lightly reinforced concrete structure below the refueling deck, and a standard industrial building at the refueling deck and above. The area above the refueling deck is equipped with automatically opening louvers to equalize pressure (a tornado design feature). Both the compartments surrounding the primary containment and the refueling deck area are served by the Standby Gas Treatment System (SGTS) which filters and releases air from the secondary containment to the environment via the 120 m high exhaust stack. 10-Oct-11 Lecture 1: Introduction & Background to 33

34 BWR Basics 10 The four Main Steam Lines (MSLs) have Main Steam Isolation Valves (MSIVs) inside & outside containment. Inside containment, the MSLs are equipped with Safety/Relief Valves (SRVs) to relieve pressure to the suppression pool when the MSLs are isolated. The primary containment (both wetwell and drywell) are inerted with nitrogen (to an oxygen concentration of less than 4%) to prevent combustion within the primary containment. 10-Oct-11 Lecture 1: Introduction & Background to 34

35 BWR Basics 11 It should be noted that in the U.S. the NRC allows BWRs to begin de-inerting up to 24 hours before a planned outage, and allows BWRs a 24-hour grace period to complete inerting during restart. This presumably also applies to BWRs in Japan, but this is not known for certain. 10-Oct-11 Lecture 1: Introduction & Background to 35

36 Spent Fuel Storage 36

37 Spent Fuel Storage 1 Spent fuel is fuel that has been used in the reactors and has been discharged and replaced by fresh fuel. The spent fuel still produces decay heat and is intensely radioactive, so it must be provided with cooling and shielding. This is accomplished, in the case of the GE BWRs with Mark I and Mark II reactors by placing the spent fuel in water-filled pools located high in the reactor buildings. The nominal capacities of the Units 1-4 pools are 900, 1240, 1220, and 1590 assemblies, respectively. At the time of the accident, the number of fuel assemblies in the pools at Units 1-4 were 292, 587, 514, and 1331, respectively. 10-Oct-11 Lecture 1: Introduction & Background to 37

38 Spent Fuel Storage 2 The spent fuel pools at Units 1-6 are all "reracked" that is, the original spent fuel storage racks have been removed and replaced by "highdensity" storage racks that permit storage of a greater number of spent fuel assemblies. The spent fuel pools at Units 1-4 are 12 m deep, with about 7 m of water normally covering the spent fuel racks. The Unit 1 pool is 12 7 m, and the pools for Units 2-4 are m. There are also a common spent fuel storage pool and a dry cask spent fuel storage facility at Fukushima Daiichi. 10-Oct-11 Lecture 1: Introduction & Background to 38

39 Spent Fuel Storage 4 The common pool is 12 m wide, 29 m long, and 11 m deep. It has a storage capacity of 6,840 assemblies (6,375 assemblies were stored on 11 March 2011). Seawater pumped through heat exchangers is used to remove decay heat. The dry cask storage facility is located in a separate building between Unit 1 and Unit 5. The facility has a capacity of 20 casks, and had 9 casks in storage at the time of the earthquake & tsunami. Casks are stored horizontally. Natural convection cooling is used to remove decay heat from the casks. 10-Oct-11 Lecture 1: Introduction & Background to 39

40 Pre-March 2011 Seismic, Tsunami & Risk Estimates 40

41 Seismic Estimates In presentations in 2009 and 2010, TEPCO stated that simultaneous seismic activity along the three tectonic plates in the sea east of Fukushima would not result in an earthquake exceeding magnitude 7.9 (M W ). In 2007, it was estimated that there was a 99% probability of an 7.5 M W earthquake in the area within the next 30 years. On 11 March 2011, the Tōhoku megathrust earthquake (9.0 M W ) struck in the Pacific Ocean 72 km east of the Oshika Peninsula & 180 km from Fukushima Daiichi (lasting 3-6 minutes). 10-Oct-11 Lecture 1: Introduction & Background to 41

42 Tsunami Estimates 1 A tsunami is a train of water waves generated by an impulsive disturbance of the water surface due to geophysical phenomena. The IAEA Safety Standard for tsunami design recommends use of "dry sites" sites not affected by tsunamis. If this option is not chosen, then the Standard recommends establishing a conservative maximum tsunami elevation, and designing safety-related structures, systems, and components accordingly. 10-Oct-11 Lecture 1: Introduction & Background to 42

43 Tsunami Estimates 2 Regardless of whether a "dry site" concept is employed, or whether permanent external barriers (levees, sea walls, and bulkheads) are constructed, as a redundant measure against flooding of the site, all plant buildings and all equipment important to safely shut down the reactor and maintain it in safe shutdown should be waterproofed. The next slide provides a historical display of tsunami sources from 1650 B.C. to 2010 A.D. As this portrayal makes clear, the ocean off the eastern coast of Japan is a major source of tsunamis. 10-Oct-11 Lecture 1: Introduction & Background to 43

44 Tsunami Sources 1650 B.C A.D. 44

45 Tsunami Estimates 3 There are three well-known earthquake/tsunami precursors in the Fukushima area: The 2 March 1933 Sanriku earthquake (8.4 M W ), which produced a tsunami with wave heights as high as 28.7 meters at Ofunato, Iwate Prefecture. The 15 June 1896 Meiji-Sanriku earthquake (7.2 M W ), which produced a tsunami with wave heights as high as 38.2 meters in Iwate & Miyagi Prefectures. The 13 July 869 Sanriku earthquake (8.1 to 8.3 M W ), which produced the Jōgan tsunami that caused flooding 4 km inland at Sendai. 10 Oct-11 Lecture 1: Introduction & Background to 45

46 Tsunami Estimates 4 In 2001, a research paper estimated the recurrence inverval for Sendai plain tsunamis at years. They stated, "More than 1100 years have passed since the Jōgan tsunami and, given the reoccurrence interval, the possibility of a large tsunami striking the Sendai plain is high." In 2007, researchers from the Geological Survey of Japan performed systematic field surveys in the Sendai and Ishinomaki plains in Japan, and found multiple sand layers indicating a tsunami recurrence interval of about 1,000 years, and concluded that such tsunamis resulted from large interplate earthquakes. A later paper (from 2009) estimated the recurrence interval at "a few hundred years". 10-Oct-11 Lecture 1: Introduction & Background to 46

47 Tsunami Estimates 5 The Fukushima Daiichi site was designed with a sea wall 5.7 meters above mean sea level (MSL). The reactor buildings and most other plant structures for Units 1-4 were designed with grade level at about 10 meters above MSL, except for the Seawater Pumps which were at 5.7 meters. For Units 5 & 6, this was increased to 13 meters above MSL. 10-Oct-11 Lecture 1: Introduction & Background to 47

48 Risk Estimates 1 The first Probabilistic Safety Assessments (PSAs) for nuclear power plants were performed in 1975 for the Surry (Westinghouse pressurized water reactor) and Peach Bottom (BWR/4 Mark I) plants in the U.S. The pre-accident core damage frequency (CDF) for the BWR/3 Mark I design was /a without accident management, and /a with accident management. The pre-accident CDF for the BWR/4 Mark I design was /a without accident management, and /a with accident management. These estimates ignored external hazards. 48

49 Risk Estimates 2 The U.S. Nuclear Regulatory Commission (NRC) required PSAs of all U.S. nuclear power plants. For the 21 BWR/3 and BWR/4 units, the internal events CDFs were 10-6 /a or higher, and all but three were /a or higher. TEPCO was thus predicting CDFs that were a factor of ten or more less than most similar American plants, but the Fukushima units had no additional systems or capabilities. The national reports of Japan for the Convention on Nuclear Safety (CNS) in 2001, 2004, 2007 and 2010 stated that a severe accident in a Japanese nuclear power plant was "technologically inconceivable". 49

50 The Fukushima Accidents 50

51 The Fukushima Accidents 1 At the time of the earthquake, Fukushima Daiichi Units 1-3 were at full power. Unit 4 was shut down and defueled (full core offloaded to spent fuel pool). Units 5 & 6 were shut down and refueled, awaiting restart. When the earthquake struck, Units 1-3 scrammed (shut down) automatically, and offsite power from six separate sources was lost (4 lines at 275 kv and 2 lines at 500 kv). The earthquake also damaged at transformer station 10 km from the site, so that even though the grid system was restored in 50 minutes, offsite power was still not able to be connected to the plant site. 51

52 The Fukushima Accidents 2 All of the 13 available EDGs (one additional EDG was out of service for maintenance) automatically started and provided emergency power. Plant safety systems functioned normally. When the tsunami waves struck the site 41 minutes after the earthquake, the waves reached more than 14 meters above MSL. The Fukushima Daiichi site was flooded (including all six units, a common spent fuel storage pool, and a dry spent fuel storage facility). 52

53 The Fukushima Accidents 3 Of the 13 available (one was out of service for maintenance) diesel generators on site, 9 were located in sub-basement levels of the turbine halls and were flooded by the tsunami (2 were at grade level behind Unit 4, and 2 were in the Unit 6 reactor building). In addition, sea water pumps providing cooling to the water-cooled diesels and other safety systems were destroyed or disabled by the tsunami waves. Two diesel fuel tanks were destroyed. Units 1-4 were in station blackout (total loss of AC power), with only battery (DC) power available. There was no cooling available to the spent fuel pools. Units 5 & 6 shared a single air-cooled EDG. 53

54 The Fukushima Accidents 4 The population living within 30 km of the site was relocated. Over the next three days, the cores of Units 1-3 melted (Unit 1 on 11 March, Unit 2 on 14 March, and Unit 3 on 13 March) due to failure of cooling systems, with core debris breaching the reactor vessels. After venting of the containments to relieve pressure, hydrogen explosions occurred at Units 1 (12 March), 3 (14 March) & 4 (15 March), destroying the reactor buildings. The containments at Units 1-3 failed, releasing (by TEPCO's estimate) 0.4% to 7% percent of the core inventories of radioactive iodine and cesium to the environment. 54

55 The Fukushima Accidents 5 At 3 a.m. on 15 March 2011, TEPCO informed the industry ministry (METI) that it was proposing to withdraw from the Fukushima facility. The Prime Minister, when informed of this, summoned the TEPCO President to his office. The discussion led to the formation of a joint Government/TEPCO integrated response office. It is estimated that along the fault the earth's crust moved upwards meters, and slipped over an area 300 km long by 150 km wide in the down dip direction. The earthquake moved the island of Honshu 2.4 meters to the east, and shifted the Earth on its axis by estimates of between 10 cm and 25 cm. 55

56 Fukushima: The Aftermath 56

57 The Aftermath 1 On 4 April 2011, TEPCO announced that it would not build the proposed Units 7 & 8 (planned ABWRs) at Fukushima Daiichi. On 12 April 2011, the Nuclear and Industrial Safety Agency (NISA, the nuclear regulatory authority) rated the accidents at INES Level 7 (the same rating as the Chornobyl accident in On 6 May, the Japanese government requested the shutdown of Hamaoka Units 3-5 until tsunami safety improvements could be implemented. 57

58 The Aftermath 2 On 20 May 2011, TEPCO's Board of Directors voted to decommission Fukushima Daiichi Units 1-4. No decision has yet been made concerning future operation of Fukushima Daiichi Units 5 & 6 or Fukushima Daini Units 1-4. On 25 May, the Swiss government ended an approval process for three new nuclear power plants, and announced that the five operating units would all be closed between 2019 and

59 The Aftermath 3 On 30 May 2011, the German government permanently closed 7 operating nuclear units as well as an 8 th unit that had been shut down at the time. The remaining 9 units are now scheduled to be shut down between 2015 and On 12 June 2011 voters in Italy rejected a government proposal to build a new generation of nuclear power plants. 59

60 The Aftermath 4 On 7 June, the Japanese government submitted a report to the IAEA concerning the Fukushima Daiichi accidents. On 16 June, the IAEA's Fact Finding Mission report on Fukushima was published. From June, the IAEA hosted a Ministerial Conference on Nuclear Safety, focused on the Fukushima accidents. 60

61 The Aftermath 5 In mid-september 2011, Siemens withdrew from the nuclear business. TEPCO faces damages of at least $59 billion for the Fukushima accidents (cleanup, decommissioning, etc.). This is the estimate of a government panel reviewing TEPCO s finances. TEPCO may face another $52 billion in compensation claims according to Bank of America Corp. TEPCO shares are down nearly 90% in value since the day before the accidents. In May 2011, TEPCO reported a full year loss of $16.3 billion, the largest loss in Japanese history for a nonfinancial company. 61

62 The Aftermath 6 The average radiation exposure in Japan before the accident was 3.91 msv/a (about 0.43 μsv/hr). On 16 March 2011, Japan's Science Ministry measured a radiation exposure level of 0.33 msv/hr at a location 20 km northwest of the Fukushima Daiichi site. This is 767,000 times the normal background rate, and this was at the edge of the area that was evacuated. TEPCO's "Nuclear Power" publication cites the normal exposure from a nuclear power plant at less than msv/a, and the legal limit at 0.05 msv/a. 62

63 The Aftermath 7 On 22 March 2011, seawater contamination was detected near the Fukushima Daiichi plant discharge. The level of Iodine-131 was found to be more than 3,300 times the legal Japanese limit, and Cesium-134 and Cesium-137 were found to be more than 100 times the limit. According to Ken Buesseler of the Woods Hole Oceanographic Institution, radioactivity in the Black Sea peaked at about 1,000 Bq/m 3 after the 1986 Chornobyl accident. By contrast, the radioactivity in the Pacific Ocean off the coast from Fukushima peaked at 100,000 Bq/m 3 in early April times greater. Before the Fukushima accident, water off the coast measured only 1.5 Bq/m 3. 63

64 Next Lecture 64

65 Next Lecture Block Lecture 2 will take place on 24 October from 18:30 20:00. We will discuss the details of the Fukushima accidents, and also discuss similarities (and differences) between the Fukushima units and nuclear power plants in Europe. 65

66 Contact Information 66

67 Contact Information Direct line: Secretariat: Institute URL (Deutsch): Course URL (English): &cperson_nr=&sprache=2 Course URL (Deutsch):