Japan Fukushima Accident Investigation Commission Report 
Photos by: Air Photo Service Co. Ltd., Japan | Article by DAVE LOCHBAUM, FORMER DIRECTOR, NUCLEAR SAFETY PROJECT

1A – Unit 1 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

1B – Unit 2 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

1C – Unit 3 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

1D – Unit 4 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

1E – Offgas building shared by all four units containing equipment to process air pulled from the condensers and reduce radioactivity discharged from the offgas stack during normal reactor operation

1F – Unit 1 reactor building with extensive damage caused by hydrogen explosion

1G – Unit 2 reactor building

1H – Unit 3 reactor building with extensive damage caused by hydrogen explosion

1I – Unit 4 reactor building with extensive damage caused by hydrogen explosion

1J – Offgas stack discharging treated flow from Units 1-4 during normal operation

1K – Unit 1 intake where sea water is pumped via underground pipes into the condenser within the Unit 1 turbine building (A) to cool the steam exiting the main turbine. The warmed sea water flows through underground pipe to a common concrete culvert to the discharge point (N).

1L – Unit 2 intake where sea water is pumped via underground pipes into the condenser within the Unit 1 turbine building (B) to cool the steam exiting the main turbine. The warmed sea water flows through underground pipe to a common concrete culvert to the discharge point (N).

1M – Unit 3 intake where sea water is pumped via underground pipes into the condenser within the Unit 1 turbine building (C) to cool the steam exiting the main turbine. The warmed sea water flows through underground pipe to a common concrete culvert to the discharge point (N).

1N – Common discharge point used by Units 1, 2, 3, and 4 to return warmed sea water to the Pacific Ocean

1O – Stack shared by the Unit 1 and Unit 2 reactor building exhaust system. Air from the reactor buildings is discharged from this stack during normal operations. During accident conditions, a system within the reactor building routes air through a charcoal filter system before sending it to the stack for discharge. The primary containment is vented through the reactor building charcoal filter system before flowing through the lines to the stack.

 

1P – Stack shared by the Unit 3 and Unit 4 reactor building exhaust system. Air from the reactor buildings is discharged from this stack during normal operations. During accident conditions, a system within the reactor building routes air through a charcoal filter system before sending it to the stack for discharge. The primary containment is vented through the reactor building charcoal filter system before flowing through the lines to the stack.

2A – Unit 1 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

2B – Unit 2 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

2C – Unit 3 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

2D – Unit 4 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

2E – Unit 1 reactor building with extensive damage caused by hydrogen explosion

 

2F – Unit 2 reactor building showing blow-out panel opened to relief hydrogen and vapor buildups

 

2G – Unit 3 reactor building with extensive damage caused by hydrogen explosion

 

2H – Unit 4 reactor building with extensive damage caused by hydrogen explosion

 

2I – Stack shared by the Unit 1 and Unit 2 reactor building exhaust system. Air from the reactor buildings is discharged from this stack during normal operations. During accident conditions, a system within the reactor building routes air through a charcoal filter system before sending it to the stack for discharge. The primary containment is vented through the reactor building charcoal filter system before flowing through the lines to the stack.

 

2J – Stack shared by the Unit 3 and Unit 4 reactor building exhaust system. Air from the reactor buildings is discharged from this stack during normal operations. During accident conditions, a system within the reactor building routes air through a charcoal filter system before sending it to the stack for discharge. The primary containment is vented through the reactor building charcoal filter system before flowing through the lines to the stack.

3A – Unit 1 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

3B – Unit 2 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

3C – Unit 3 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

3D – Unit 1 reactor building with extensive damage caused by hydrogen explosion

 

3E – Unit 2 reactor building

 

3F – Unit 3 reactor building with extensive damage caused by hydrogen explosion

 

3G – Stack shared by the Unit 1 and Unit 2 reactor building exhaust system. Air from the reactor buildings is discharged from this stack during normal operations. During accident conditions, a system within the reactor building routes air through a charcoal filter system before sending it to the stack for discharge. The primary containment is vented through the reactor building charcoal filter system before flowing through the lines to the stack.

 

3H – Unit 1 reactor building (D) exhaust line to the stack (G)

 

3I – Unit 2 reactor building (E) exhaust line to the stack (G)

 

3J – Unit 1 truck bay used to deliver canisters of new fuel assemblies into the reactor building (D) and its refueling floor

 

3K – Unit 2 truck bay used to deliver canisters of new fuel assemblies into the reactor building (D) and its refueling floor

 

3L – Unit 3 truck bay used to deliver canisters of new fuel assemblies into the reactor building (D) and its refueling floor

4A – Unit 2 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

4B – Unit 3 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

4C – Unit 4 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

4D – Unit 3 reactor building with extensive damage caused by hydrogen explosion

 

4E – Unit 4 reactor building with extensive damage caused by hydrogen explosion

 

4F – Unit 3 reactor building (D) exhaust line to the stack (H) showing extensive damage

 

4G – Unit 4 reactor building (E) exhaust line to the stack (H)

 

4H – Stack shared by the Unit 3 and Unit 4 reactor building exhaust system. Air from the reactor buildings is discharged from this stack during normal operations. During accident conditions, a system within the reactor building routes air through a charcoal filter system before sending it to the stack for discharge. The primary containment is vented through the reactor building charcoal filter system before flowing through the lines to the stack.

 

4I – Offgas building shared by all four units containing equipment to process air pulled from the condensers and reduce radioactivity discharged from the offgas stack during normal reactor operation

 

4J – Offgas stack discharging treated flow from Units 1-4 during normal operation

5A – Unit 3 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

5B – Unit 4 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

5C – Unit 2 offgas line that transports air pulled from the condenser inside the Unit 2 turbine building during normal operation to the offgas building for treatment to reduce radioactivity levels before discharge to the atmosphere

 

5D – Unit 3 offgas line that transports air pulled from the condenser inside the Unit 2 turbine building during normal operation to the offgas building for treatment to reduce radioactivity levels before discharge to the atmosphere

 

5E – Unit 3 reactor building (H) exhaust line to the stack (G) showing extensive damage

 

5F – Unit 4 reactor building (I) exhaust line to the stack (G)

 

5G – Stack shared by the Unit 3 and Unit 4 reactor building exhaust system. Air from the reactor buildings is discharged from this stack during normal operations. During accident conditions, a system within the reactor building routes air through a charcoal filter system before sending it to the stack for discharge. The primary containment is vented through the reactor building charcoal filter system before flowing through the lines to the stack.

 

5H – Unit 3 reactor building with extensive damage caused by hydrogen explosion

 

5I – Unit 4 reactor building with extensive damage caused by hydrogen explosion

6A – Unit 3 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

6B – Unit 4 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps

 

6C – Unit 3 reactor building with extensive damage caused by hydrogen explosion

 

6D – Unit 4 reactor building with extensive damage caused by hydrogen explosion

 

6E – Unit 3 main transformer showing three parallel bus ducts connecting the main transformer to the Unit 3 turbine building (A) housing the main generator

 

6F – Unit 4 main transformer showing three parallel bus ducts connecting the main transformer to the Unit 3 turbine building (B) housing the main generator

 

6G – Unit 3 reactor building (C) exhaust line to the stack (I) showing extensive damage

 

6H – Unit 4 reactor building (D) exhaust line to the stack (I)

 

6I – Stack shared by the Unit 3 and Unit 4 reactor building exhaust system. Air from the reactor buildings is discharged from this stack during normal operations. During accident conditions, a system within the reactor building routes air through a charcoal filter system before sending it to the stack for discharge. The primary containment is vented through the reactor building charcoal filter system before flowing through the lines to the stack.

 

6J – Unit 3 truck bay used to deliver canisters of new fuel assemblies into the reactor building (D) and its refueling floor

 

6K – Unit 4 truck bay used to deliver canisters of new fuel assemblies into the reactor building (D) and its refueling floor

 

6L – Unit 3 access hatch connecting the truck bay elevation with the refueling floor elevation inside the Unit 3 reactor building (C)

 

6M – Unit 4 drywell head (yellow). Unit 4 was in a refueling shutdown at the time with the drywell head and reactor vessel head removed to allow access to the reactor core.

7A – Unit 3 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps. Roof damage possibly caused by debris from the Unit 3 reactor building (B) explosion

 

7B – Unit 3 reactor building with extensive damage caused by hydrogen explosion

 

7C – Unit 2 offgas line that transports air pulled from the condenser inside the Unit 2 turbine building during normal operation to the offgas building for treatment to reduce radioactivity levels before discharge to the atmosphere

 

7D – Unit 3 offgas line that transports air pulled from the condenser inside the Unit 2 turbine building during normal operation to the offgas building for treatment to reduce radioactivity levels before discharge to the atmosphere

 

7E – Unit 3 reactor building (B) exhaust line to the stack showing extensive damage

 

7F – Unit 3 truck bay used to deliver canisters of new fuel assemblies into the reactor building (B) and its refueling floor

 

7G – Unit 3 access hatch connecting the truck bay elevation with the refueling floor elevation inside the Unit 3 reactor building (B)

Roger Witherspoon

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