Progress report

I. Confirmation of the reactor conditions

II. Progress status by each plan

I. Confirmation of the reactor conditions

1. Temperatures inside the reactors

Through continuous reactor cooling by water injection, the temperatures of the Reactor Pressure Vessel (RPV) bottom and the Primary Containment Vessel (PCV) gas phase have been maintained within the range of approx. 15 to 25°C for the past month, though they vary depending on the unit and location of the thermometer.

2. Release of radioactive materials from the Reactor Buildings

As of January 2017, the density of radioactive materials newly released from Reactor Building Units 1-4 in the air and measured at the site boundary was evaluated at approx. 3.5テ10-12 Bq/cm3 for Cs-134 and 1.1テ10-11 Bq/cm3 for Cs-137 at the site boundary. The radiation exposure dose due to the release of radioactive materials was less than 0.00029 mSv/year at the boundary.

Note: Different formulas and coefficients were used to evaluate the radiation dose in the facility operation plan and monthly report. The evaluation methods were integrated in September 2012. As the fuel removal from the spent fuel pool (SFP) commenced for Unit 4, the radiation exposure dose from Unit 4 was added to the items subject to evaluation since November 2013. The evaluation has been changed to a method considering the values of continuous dust monitors since FY2015, with data to be evaluated monthly and announced the following month.

3. Other indices

There was no significant change in indices, including the pressure in the PCV and the PCV radioactivity density (Xe-135) for monitoring criticality, nor was any abnormality in the cold shutdown condition or criticality sign detected.

Based on the above, it was confirmed that the comprehensive cold shutdown condition had been maintained and the reactors remained in a stabilized condition.

II. Progress status by each plan

1. Contaminated water countermeasures

To tackle the increase in accumulated water due to groundwater inflow, fundamental measures to prevent such inflow into the Reactor Buildings will be implemented, while improving the decontamination capability of water treatment and preparing facilities to control the contaminated water

Operation of groundwater bypass

Water treatment facility special for Subdrain& Groundwater drain

Figure1: Evaluation of inflow into buildings after the subdrains went into operation

Construction status of land-side impermeable walls

Figure2: Closure of part of the land-side impermeable walls(on the mountain side)

*1:Water amount with which water-level gauge indicates 0% or more
*2:Since September 10, 2015, the data collection method has been changed (Evaluation based on increased in storage: in buildings and tanks 竊 Evaluation based on increase/decrease in storage in buildings)
 窶廬nflow of groundwater/rainwater into buildings窶 = 窶廬ncrease/decrease of water held in buildings窶
 +窶弋ransfer from buildings to tanks窶 - 窶弋ransfer into buildings (water injection into reactors and transfer from well points, etc.)窶
*3:Since April 23, 2015, the data collection method has been changed. (Increase in storage (1)+(2) 竊 (1)+(2)+*)
*4:On February 4, 2016 and January 19, 2017, corrected by reviewing the water amount of remaining concentrated salt water
*5:窶廬ncrease/decrease of water held in buildings窶 used to evaluate 窶廬nflow of groundwater/rainwater into buildings窶 and 窶彜torage increase窶 is calculated based on the data from the water-level gauge.
 During the following evaluation periods, when the gauge was calibrated, these two values were evaluated lower than anticipated. (March 10-17, 2016: Main Process Building; March 17-24, 2016:
 High-Temperature Incinerator Building (HTI); September 22-29, 2016: Unit 3 Turbine Building)
*6:For rainfall, data of Namie (from data published by the Japan Meteorological Agency) is used. However, due to missing values, data of Tomioka (from data published by the Japan Meteorological Agency)
 is used alternatively (April 14-21, 2016)

Figure3: Status of accumulated water storage

Operation of multi-nuclide removal equipment

Toward reducing the risk of contaminated water stored in tanks

Measures in Tank Areas

Closure of Unit 2 seawater pipe trench vertical shaft C

Progress of accumulated water treatment in the Unit 1 T/B

2. Fuel removal from the spent fuel pools

Work to help remove spent fuel from the pool is progressing steadily while ensuring seismic capacity and safety. The removal of spent fuel from the Unit 4 pool commenced on November 18, 2013 and was completed on December 22, 2014

Main work to help remove spent fuel at Unit 1

Main work to help remove spent fuel at Unit 2

Main work to help remove spent fuel at Unit 3

3. Removal of fuel debris

Promoting the development of technology and collection of data required to prepare fuel debris removal, such as investigations and repair of PCV's leakage parts as well as decontamination and shielding to improve PCV accessibility.

Dose reduction on the Unit 1-3 Reactor Building 1st floors

Status toward investigation inside the Unit 1 PCV

Status toward an investigation inside the Unit 2 PCV

4. Plans to store, process and dispose of solid waste and decommission of reactor facilities

Promoting efforts to reduce and store waste generated appropriately and R&D to facilitate adequate and safe storage, processing and disposal of radioactive waste

Management status of rubble and trimmed trees

Management status of secondary waste from water treatment

5. Reactor cooling

The cold shutdown condition will be maintained by cooling the reactor by water injection and measures to complement the status monitoring will continue

Reduction of volume of water injected into the Unit 1-3 reactors

6. Reduction in radiation dose and mitigation of contamination

Effective dose-reduction at site boundaries and purification of port water to mitigate the impact of radiation on the external environment

Status of groundwater and seawater on the east side of Turbine Building Units 1 to 4

<Unit 1 intake north side, between Unit 1 and 2 intakes>

<Between Unit 2 and 3 intakes, between Unit 3 and 4 intakes>
Figure5: Groundwater density on the Turbine Building east side

Figure6: Seawater density around the port

7. Outlook of the number of staff required and efforts to improve the labor environment and conditions

Securing appropriate staff long-term while thoroughly implementing workers' exposure dose control. Improving the work environment and labor conditions continuously based on an understanding of workers' on-site needs

Staff management

Figure7: Changes in the average number of workers per weekday for each month since FY2014

Figure8: Changes in monthly individual worker exposure dose
(monthly average exposure dose since March 2011)

Measures to prevent infection and expansion of influenza and norovirus

Status of influenza and norovirus cases

Operation start of the partner company building

8. Status of Unit 5 and 6

Water level increase at mega float No. 5VOID (north side)