Reference February 16, 2017 Tokyo Electric Power Company Holdings, Inc.

Transcription

1 Reference February 16, 2017 Tokyo Electric Power Company Holdings, Inc. Unit 2 Primary Containment Vessel Investigation at Fukushima Daiichi Nuclear Power Station (Investigation results by the self-propelled investigation device)

2 1. 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 unit * Drilling device Drilling device Hole saw Clamp * Combination of isolation and shielding Step 4. Preinvestigation of X-6 penetration 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 CRD rail Pan-tilt camera CRD rail Pan-tilt camera Deposit removal device Self-propelled investigation device 1 Images provided from International Research Institute for Nuclear Decommissioning (IRID)

3 2. Investigation results by the self-propelled investigation device (digital images) Step 7 Guide pipe for pre-investigation (Φ110mm) 自走式調査装置による調査概要 Chamber unit Alternative shielding Platform Inside of PCV Self-propelled investigation device (cameras, dosimeter, thermometer) Shooting range Investigation by the self-propelled investigation device Hanging balance opening 画像提供 : 国際廃炉研究開発機構 (IRID) 2

4 2. Investigation results by the self-propelled investigation device (temperatures and radiation levels) * Calculated from integrating radiation dose for about four minutes. Estimated value from noise images: about 5-13Sv/h Note) Could be affected by the lighting Dose rate Step 7 Guide pipe for pre-investigation (Φ110mm) About 210Sv/h * 自走式調査装置による調査概要 Chamber unit Alternative shielding Inside of PCV Platform Temperature Investigation by the self-propelled investigation device 16.5 Reference: temperature inside the PCV: 18.6 (as of 8:00 a.m.) TE C Temperatures have been evaluated from the sequentially obtained data. 3

5 4. Summary Today s investigation results The self-propelled investigation device ran on the deposits of the CRD rail and reached the area toward the pedestal (the vicinity of hanging balance), further than the area where the deposit removal device reached. It tried to move further toward the pedestal but could not reach there because the crawler belt on the left side could not move any more. It investigated temperatures and radiation levels on the CRD rail as well as conditions of surrounding structures. The connection cable was cut and the device was left on the side of the CRD rail not to obstruct further investigations. Plans for further examination TEPCO will continue to evaluate the information, such as deposits on the CRD rail and conditions inside the pedestal, obtained from this entire investigation. 4

6 Reference: Location where the device was left Step 7 Guide pipe for pre-investigation (Φ110mm) 自走式調査装置による調査概要 Chamber unit Alternative shielding Platform Inside of PCV Self-propelled investigation device (cameras, dosimeter, thermometer) Shooting range Investigation by the self-propelled investigation device CRD rail End of CRD rail Guiding pipe slope Images provided from International Research Institute for Nuclear Decommissioning (IRID) Location where the device was left 5