Based on the Restoration Plan (submitted and published on January 31, 2012) prepared in accordance with the Nuclear Operator Emergency Action Plan, Fukushima Daini Nuclear Power Station is now proceeding with restoration of facilities for maintaining cold shutdown of the station. We report the restoration progress status at the end of May 2012 as shown below:
1. Progress Status of the Restoration Plan
On May 17, 2012, the restoration (permanent installation) of the equipments/facilities necessary to maintain cold shutdown state has been completed for Unit 4. The internal inspection after the permanent installation of equipments/facilities has also been completed. An interim progress report was created and submitted to the government on May 31 (As mentioned in the press release issued on May 31, 2012). The restoration work for Unit 1-3 is proceeding steadily.
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- % in the chart shows the progress rate of restoration work as per the Restoration Plan (Up to the
permanent installation) as of the end of May, 2012. % in ( ) shows the progress rate of the
previous monthly report. See Appendix 1 for details.
- At the internal inspection after the permanent installation, the equipments subject to the Restoration Plan will be tested (for each unit).
Note: For Units 2 and 3, the rate is the same as the previous month because there was no change in each step. However, the restoration tasks are proceeding steadily.
2. Major Progresses Based on the Restoration Plan (May)
Installation of the electric motor of Unit 1 residual heat removal cooling system (C system)
The electric motor of Unit 1 residual heat removal cooling system (C system) was fixed and temporarily placed on the second floor of Unit 3 Turbine Building to reduce the impact of recurrent Tsunami. After the water-tight work was completed for the Seawater Heat Exchanger Building on March 31, 2012 (as mentioned in the press release issued on the same day), the system was moved back to the first floor of Unit 1 Seawater Heat Exchanger Building on May 22 (Permanent installation completed). [See Appendix 1 & 2] A function check will be performed during the test operation and the power panel and the permanent cable will be installed.
Installation of the electric motor of Unit 1 residual heat removal cooling seawater system (C system)
The electric motor of Unit 1 residual heat removal cooling seawater system (C system) was fixed and temporarily placed on the second floor of Unit 1 Seawater Heat Exchanger Building to reduce the impact of recurrent Tsunami. After the water-tight work was completed for the Seawater Heat Exchanger Building on March 31, 2012, the system was moved back to the first floor of the building on May 15 (Permanent installation completed). [See Appendix 1 & 2] A function check will be performed during the test operation and the power panel and the permanent cable will be installed.
Permanent installation of Unit 4 reactor coolant filtering system purge line (A system, B system)
On May 17, 2012, the permanent installation of Unit 4 reactor coolant filtering system purge line*1 (A, B) was completed as the temporary hose was switched to the permanent pipes/valves and the test operation was done (in which no problem was found). [See Appendix 1 & 2]
3. Other Major Progresses (May)
Visual inspection of the inside of Unit 2 PCV
Visual inspection of the inside of Unit 2 PCV was completed on May 29, 2012. As we found no leakage of reactor coolant or deformation/damage of equipments and piping inside PCV, it has been concluded that there are no factors hindering the cold shutdown function. Though minor issues were found such as the paint inside PCV partially coming off (due to the temporary temperature rise after the plant shutdown) and rust on the surface of some equipments (due to humidity change), these do not have impact on the cold shutdown function (as informed on May 29, 2012). [See Appendix 3]
In accordance with the four points to consider*2 specified by the Nuclear Safety Commission when the cancellation of a nuclear emergency situation was declared, TEPCO is committed to continuously pursuing the measures for restoration from nuclear emergency and further reliability improvement.
As for the consideration point 4, the systems subject to the measures were selected at the end of March 2012. We are currently in the process of assessing impact on the selected systems.
End
Appendixes
1: Fukushima Daini Nuclear Power Station: Progress Status Based on the Restoration Plan (As of the End of May 2012)(PDF 57.7KB)
2: < Photos > Major Progress Statuses Based on the Restoration Plan (May)(PDF 90.2KB)
- Installation of the electric motor of Unit 1 residual heat removal cooling system (C system)
- Installation of the electric motor of Unit 1 residual heat removal cooling seawater system (C system)
- Permanent installation of Unit 4 reactor coolant filtering system purge line (A system, B system)
3: < Photos > Other Major Progresses (May)(PDF 119KB)
- Visual inspection of the inside of Unit 2 PCV
4: < Photos > Other Topics(PDF 192KB)
- The Impact of the Earthquake and the Tsunami on Unit 1-4 Turbine Buildings and the Current Statuses
*1 Purge line: Seal water line of reactor water cleanup system pump
*2 Four points to consider specified by Nuclear Safety Commission
On December 26, 2011, the Nuclear Safety Commission submitted a proposal to the Prime Minster that the cancellation of a nuclear emergency situation of the TEPCO Fukushima Daini Nuclear Power Station is allowed to be declared, along with four points to consider for the issuance of the declaration. On January 11, 2012, the Nuclear and Industrial Safety Agency at the Ministry of Economy, Trade and Industry issued instructions to observe the consideration points when preparing and implementing the Restoration Plan for Fukushima Daini Nuclear Power Station.
1. Part of the facilities at the Fukushima Daini Nuclear Power Station is temporary installation, to which appropriate maintenance should be provided. The dependence rate of the temporary installation should be reduced according to a plan.
2. The safety facilities for part of the residual heat removal systems have not yet been recovered, to which appropriate management should be provided according to the situation until the restoration of these facilities. In preparing for natural disasters and other incidents, all possible measures should be taken to ensure safety.
3. Thorough safety management including the safety of workers should be implemented.
4. Based on the past pressure and temperature records before cold shutdown that showed abnormal values different from those during a regular period, impacts of these elements on the facilities should be considered.
