Pre-investigation results of X-6 penetration for the Unit 2 Primary Containment Vessel Investigation at Fukushima Daiichi Nuclear Power Station

Transcription

1 Reference January 26, 2017 Tokyo Electric Power Company Holdings, Inc. Pre-investigation results of for the Unit 2 Primary Containment Vessel Investigation at Fukushima Daiichi Nuclear Power Station

2 1. Unit 2 Primary Containment Vessel investigation The purpose of this investigation is to inspect the platform inside the pedestal, fuel debris fallen to the Control Rod Drive (CRD), and structures inside the pedestal. Today, preparatory investigation was conducted for and CRD exchange rail which the self-propelled Scorpion robot will take to the pedestal. opening Control Rod Drive (CRD) exchange rail Primary Containment Vessel (PCV) RPV Control Rod Drive (CRD) Today s investigation area About 7.2m Platform Basement floor Investigation area inside the pedestal 1

3 3. Work steps for Unit 2 PCV investigation Step 1. Drilling device carried in Step 2. Drilling device set up Step 3. Drilling on Drilling device Shielding Isolation Isolation unit * Drilling device Drilling device Hole saw Clamp The step taken today * Combination of isolation and shielding Step 4. Pre-investigation of and CRD rail using guide pipe Step 5. Pre-investigation inside pedestal using guide pipe Step 6. Obstacle removal device inserted * * The device may not be inserted depending on the obstacle conditions. Step 7. Investigation using selfpropelled investigation device Pan-tilt camera Pan-tilt camera Obstacle removal device 2 Self-propelled investigation device 2

4 3. Pre-investigation results for (1/3) Step 4 Isolation valve Pan-tilt camera and lights Radiation dose inside PCV: about 73 Sv/h (Maximum measurement value in March 2012) Guide pipe for re-investigation (Φ110mm) Alternative shielding Shooting range パンチルトカメラ 照明 Inside of Primary Containment Vessel Sling Platform Control Rod Drive (CRD) Outlie of pre-investigation for and using guide pipe Inside of isolation unit Surface of Inside of Inside of Cable 3

5 3. Pre-investigation results for (2/3) Step 4 Isolation valve Guide pipe for pre-investigation (Φ110mm) Radiation dose inside PCV: about 73 Sv/h (Maximum measurement value in March 2012) Pan-tilt camera and lights Sling Alternative 代替遮へい体 shielding パンチルトカメラ 照明 Platform Control Rod Drive (CRD) Inside of Primary Containment Vessel Shooting range Outlie of pre-investigation for and using guide pipe 4

6 3. Pre-investigation results for (3/3) Step 4 Isolation valve Guide pipe for pre-investigation (Φ110mm) Radiation dose inside PCV: about 73 Sv/h (Maximum measurement value in March 2012) 2.3m Sling Alternative shielding パンチルトカメラ 照明 Inside of Primary Containment Vessel Platform Control Rod Drive (CRD) Shooting range Outlie of pre-investigation for and using guide pipe 5

7 4. Summary Investigation results As an investigation result for, necessary space was found to insert the guide pipe (about Φ110 mm ) used in the next investigation steps. As an investigation result for, no obstacles were found in today s investigation area, which could prevent next pre-investigation for the pedestal. Although the image is not clear around the pedestal opening due to mist, the conditions will be inspected in the next pre-investigation for the pedestal, as planned. Future plans Pre-investigation will begin after necessary preparation is made, reflecting today s pre-investigation results to the next pre-investigation plan for the pedestal. 6

8 Reference: Work site scenes The pre-investigation was conducted by remotely operating the camera at the field headquarters and by inserting/pulling out the guide pipe inside the Unit 2 Reactor Building. Field headquarters Inside of Unit 2 Reactor Building Work site scenes 7