​Fukushima in 2016

Current condition of the Fukushima Daiichi plant
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Fukushima Daiichi in 2016:

Situation of the nuclear installations

​IRSN publishes on this page its information notes on the state of the facilities of the Fukushima Daiichi nuclear power plant, based on publicly available information.

Situation of the nuclear installations

Fukushima Daiichi in 2016:

Situation of the nuclear installations

​IRSN publishes on this page its information notes on the state of the facilities of the Fukushima Daiichi nuclear power plant, based on publicly available information.

Condition of the facilities

Facility control actions

Reactors 1, 2 and 3 are now maintained at a temperature between 20 and 50°C by continuous injection of fresh water (at a flow rate of the order of 5 m3/h per reactor). In addition, nitrogen is injected as required into the containment and the tanks of Reactors 1-3 to maintain their inerting and thus avoid any risk of hydrogen combustion. The fuel pools are cooled in a closed circuit; the temperatures in the pools are lower than 30°C.

IRSN emphasises the importance of the provisions implemented by TEPCO for the control of the facilities in a persistently difficult environment linked to a still limited knowledge of the condition of the facilities, reduced accessibility to the damaged buildings, restrictive intervention conditions and the current level of reliability of some of the resources implemented.

Plant control recovery plan​

In 2016, site clean-up actions continue to enable the completion of the control recovery plan in 3 stages:

Removal of the fuel from the pools – starting in 2017 for the pool of Reactor 3 and in 2020 for those of Reactors 1 and 2;Removal of the degraded fuel of Reactors 1, 2 and 3 between 2020 and 2025. This schedule remains highly dependent on the research programme and knowledge obtained about the condition of the facilities; Full dismantling of the facilities, with a goal of 30 to 40 years.

In 2015, TEPCO adjusted the schedule for the implementation of the first stage. For the pool of Reactor 3, the start of the fuel retrieval was postponed from late 2015 to late 2017. Beforehand, the operator has initiated the construction of a structure covering the reactor building. In 2015, a fuel handling crane - that has fallen during the accident - was removed from the pool, which was an important step to enable the future removal of the fuel.

TEPCO also postponed the fuel retrieval in the pools of Reactors 1 and 2 until 2020. Significant work still needs to be done on Reactor 1: the current protection building should be dismantled to allow the removal of debris; a new building will be built for the fuel retrieval.

IRSN emphasises that the deadlines announced should be considered as orders of magnitude and that significant operations to further characterise the state of the facilities, as well as research work, still need to be done.

IRSN notes, however, the importance of the means implemented by TEPCO to keep to the overall schedule announced.

 

Download "Situation of the facilities in March 2016" (PDF, 378 Ko)

 

​Fukushima Daiichi Nuclear Power Plant in March 2011. © DigitalGlobe

Condition of the facilities

Condition of the facilities

​Fukushima Daiichi Nuclear Power Plant in March 2011. © DigitalGlobe

Facility control actions

Reactors 1, 2 and 3 are now maintained at a temperature between 20 and 50°C by continuous injection of fresh water (at a flow rate of the order of 5 m3/h per reactor). In addition, nitrogen is injected as required into the containment and the tanks of Reactors 1-3 to maintain their inerting and thus avoid any risk of hydrogen combustion. The fuel pools are cooled in a closed circuit; the temperatures in the pools are lower than 30°C.

IRSN emphasises the importance of the provisions implemented by TEPCO for the control of the facilities in a persistently difficult environment linked to a still limited knowledge of the condition of the facilities, reduced accessibility to the damaged buildings, restrictive intervention conditions and the current level of reliability of some of the resources implemented.

Plant control recovery plan​

In 2016, site clean-up actions continue to enable the completion of the control recovery plan in 3 stages:

Removal of the fuel from the pools – starting in 2017 for the pool of Reactor 3 and in 2020 for those of Reactors 1 and 2;Removal of the degraded fuel of Reactors 1, 2 and 3 between 2020 and 2025. This schedule remains highly dependent on the research programme and knowledge obtained about the condition of the facilities; Full dismantling of the facilities, with a goal of 30 to 40 years.

In 2015, TEPCO adjusted the schedule for the implementation of the first stage. For the pool of Reactor 3, the start of the fuel retrieval was postponed from late 2015 to late 2017. Beforehand, the operator has initiated the construction of a structure covering the reactor building. In 2015, a fuel handling crane - that has fallen during the accident - was removed from the pool, which was an important step to enable the future removal of the fuel.

TEPCO also postponed the fuel retrieval in the pools of Reactors 1 and 2 until 2020. Significant work still needs to be done on Reactor 1: the current protection building should be dismantled to allow the removal of debris; a new building will be built for the fuel retrieval.

IRSN emphasises that the deadlines announced should be considered as orders of magnitude and that significant operations to further characterise the state of the facilities, as well as research work, still need to be done.

IRSN notes, however, the importance of the means implemented by TEPCO to keep to the overall schedule announced.

 

Download "Situation of the facilities in March 2016" (PDF, 378 Ko)

 

Release control actions

Diffuse releases into the environment continue due to the very serious deterioration of the confinment barriers. TEPCO is continuing its actions to control these emissions, notably with the establishment of structures covering the buildings of the damaged reactors and underground barriers to manage groundwater.

The volume of water accumulated in the storage tanks and basements of the buildings reached nearly 900 000 m3 in early 2016.

Management of radioactive water

In 2015, a major milestone in the decontamination of water was completed. Since May 2015, around 600 000 m3 of water were treated with the ALPS radionuclide removal system and around 150 000 m3 were partially treated (removal of caesium and strontium, before complete treatment later on). The waste of the treatment processes have led to the filling of nearly 3 000 containers of radioactive waste, which are stored at the site.

Water treatment is only a first step towards managing the water accumulated on the site. Indeed, it is necessary for TEPCO to obtain authorisations for the release of treated water still containing residual radioactivity (mainly tritium). This situation forces TEPCO to store ever increasing volumes of water. The storage capacity has now reached about 1 000 000 m3.

Following the leakages found in the storage area, TEPCO decided to replace some types of tanks with welded tanks and initiated a vast retention area renovation and improvement programme. These developments, combined with the tightening of the surveillance, improved the management of the water storage facilities.

Download "Management of radioactive water from the damaged reactors" (PDF, 413 Ko)

 

Groundwater under the site

In early 2016, it appears that the provisions implemented by TEPCO enable the bulk of the groundwater contamination to be contained within the Fukushima Daiichi plant.

In order to understand the sources of radioactive contamination of the groundwater under the site, three different areas should be considered:

The inlet channel area

This area is located next to the harbour. Shortly after the accident, highly radioactive water from the reactors filled several trenches and passages and then spilled into the harbour.

With the draining of the trenches, the establishment of sealing barriers and pumping wells, TEPCO considers that it has managed to minimise the diffuse releases of contaminated groundwater into the ocean.

The nuclear buildings area 

The basements of these buildings are filled with highly radioactive reactor cooling water  (of the order of 70 000 m3). In addition, they receive significant inflows of groundwater (about 200 m3/day).

After a year of operation, TEPCO estimated in summer 2015 that the upstream pump wells - the "groundwater bypass wells" – had reduced seepage into the buildings from 400 to 300 m3/day. According to statements made by TEPCO in late 2015, the commissioning of the pumps in the drainage pits - the "subdrains" - around the buildings has also reduced seepage from 300 to 200 m3/day.

A test showed encouraging results with regard to freezing the ground. However, since August 2015 and the beginning of the rainy season, increased groundwater flows have led to a rise of soil temperature in most of the boreholes.

The tanks area

Created after the accident to manage the highly radioactive water pumped on the site, this tank installation area covers an area five times larger than that of the nuclear buildings. To date, around 750 000 m3 of radioactive water are stored there.

The implementation of the water treatment has reduced the radiological content of the water. Since the commissioning of the "groundwater bypass" in 2014, most of the contaminated groundwater from this area is captured by this device. Only the tritium remains detectable.

Download "Groundwater under the site" (PDF, 829 Ko)

 

Go to the next part : Environmental impact

​Metal tanks containing contaminated water at the Fukushima Daiichi plant. December 2013 © Guillaume Bression / Fabien Recoquillé / IRSN

Release control actions

Release control actions

​Metal tanks containing contaminated water at the Fukushima Daiichi plant. December 2013 © Guillaume Bression / Fabien Recoquillé / IRSN

Diffuse releases into the environment continue due to the very serious deterioration of the confinment barriers. TEPCO is continuing its actions to control these emissions, notably with the establishment of structures covering the buildings of the damaged reactors and underground barriers to manage groundwater.

The volume of water accumulated in the storage tanks and basements of the buildings reached nearly 900 000 m3 in early 2016.

Management of radioactive water

In 2015, a major milestone in the decontamination of water was completed. Since May 2015, around 600 000 m3 of water were treated with the ALPS radionuclide removal system and around 150 000 m3 were partially treated (removal of caesium and strontium, before complete treatment later on). The waste of the treatment processes have led to the filling of nearly 3 000 containers of radioactive waste, which are stored at the site.

Water treatment is only a first step towards managing the water accumulated on the site. Indeed, it is necessary for TEPCO to obtain authorisations for the release of treated water still containing residual radioactivity (mainly tritium). This situation forces TEPCO to store ever increasing volumes of water. The storage capacity has now reached about 1 000 000 m3.

Following the leakages found in the storage area, TEPCO decided to replace some types of tanks with welded tanks and initiated a vast retention area renovation and improvement programme. These developments, combined with the tightening of the surveillance, improved the management of the water storage facilities.

Download "Management of radioactive water from the damaged reactors" (PDF, 413 Ko)

 

Groundwater under the site

In early 2016, it appears that the provisions implemented by TEPCO enable the bulk of the groundwater contamination to be contained within the Fukushima Daiichi plant.

In order to understand the sources of radioactive contamination of the groundwater under the site, three different areas should be considered:

The inlet channel area

This area is located next to the harbour. Shortly after the accident, highly radioactive water from the reactors filled several trenches and passages and then spilled into the harbour.

With the draining of the trenches, the establishment of sealing barriers and pumping wells, TEPCO considers that it has managed to minimise the diffuse releases of contaminated groundwater into the ocean.

The nuclear buildings area 

The basements of these buildings are filled with highly radioactive reactor cooling water  (of the order of 70 000 m3). In addition, they receive significant inflows of groundwater (about 200 m3/day).

After a year of operation, TEPCO estimated in summer 2015 that the upstream pump wells - the "groundwater bypass wells" – had reduced seepage into the buildings from 400 to 300 m3/day. According to statements made by TEPCO in late 2015, the commissioning of the pumps in the drainage pits - the "subdrains" - around the buildings has also reduced seepage from 300 to 200 m3/day.

A test showed encouraging results with regard to freezing the ground. However, since August 2015 and the beginning of the rainy season, increased groundwater flows have led to a rise of soil temperature in most of the boreholes.

The tanks area

Created after the accident to manage the highly radioactive water pumped on the site, this tank installation area covers an area five times larger than that of the nuclear buildings. To date, around 750 000 m3 of radioactive water are stored there.

The implementation of the water treatment has reduced the radiological content of the water. Since the commissioning of the "groundwater bypass" in 2014, most of the contaminated groundwater from this area is captured by this device. Only the tritium remains detectable.

Download "Groundwater under the site" (PDF, 829 Ko)

 

Go to the next part : Environmental impact