CONSULTING

around 4.4 m 3 /hour. 270 Therefore, five years after the beginning of the accident, every day, over
300 m 3 of water have to be injected into the three reactor cores.
At unit 1, the building cover for preventing radioactive material diffusion is being dismantled to
enable the removal of spent fuel from the storage pool. According to current planning, debris
removal work will continue until FY2018, and then cranes and handling equipment will be installed
for spent fuel removal by FY2020.
At unit 2, preparation for dismantling the building roof began in April 2016. The method of spent
fuel removal has not been determined yet.
At unit 3, debris is being removed from the building roof and spent fuel pool. Similar to unit 1,
cranes and handling equipment will be installed for spent fuel removal.
The spent fuel removed from unit 1 through 3 will be stored in the common storage pool as in the
case of unit 4. The long-term storage method is planned to be determined around FY2020.
A large number of workers had been exposed to radiation in order to get video footage of the
conditions in the containment vessels. 271 However, from April 2015, radiation surveys using robots
began. For example, 9.7 Sv/h was measured in unit 1 during the first survey. 272 Several of these
robots have only lasted for a few minutes before their electronics including computer chips were
destroyed by the intense radiation fluxes.
As for the measurement of fuel debris, the data obtained from the survey implemented in
March 2015 at unit 1 revealed that there is no significant volume of fuel material in the reactor core
and no progress has been made in collecting detailed data of the fuel debris.
In other words, it remains unknown where the fuel is.
Contaminated Water Management
A dedicated bypass system has been operational since 2014 with pumps underground water into
the sea after analyzing its quality subsequent to storage in temporary storage tanks. 273 As of
March 2016, the inflow of underground water to the reactor building was reduced from around
400 m 3 /day to about 150 to 200 m 3 /day. 274
Since 2 September 2015, Tokyo Electric Power Company (TEPCO) has also started pumping
groundwater using subdrains—41 wells around the buildings and 5 wells on the sea side. Similarly,
270 TEPCO, “The parameters related to the plants in Fukushima Daiichi Nuclear Power Station”, see
http://www.tepco.co.jp/en/nu/fukushima-np/f1/pla/2016/images/table_summary-e.pdf, accessed 23 June 2016.
271 For example, 51 workers were needed for the approx. 3-hour video-taping carried out in 2012. This is
most likely because a large number of workers were required to reduce the radiation dose per person amidst
implementing the task involving high-level exposures to radiation. Source: TEPCO, (in Japanese), see
http://www.tepco.co.jp/nu/fukushima-np/images/handouts_121011_08-j.pdf, accessed 12 April 2016.
272 TEPCO, “The development of the reactor containment vessel interior investigation technology”,
30 April 2015, (in Japanese), see http://www.tepco.co.jp/nu/fukushimanp/handouts/2015/images/handouts_150430_01-j.pdf,
accessed 12 April 2016.
273 For example, following are the results of the pre-discharge storage tank samples collected on 5 April 2016:
ND for caesium 134 and caesium 137 and 180Bq/l for tritium. See TEPCO, “The sampling results regarding the
groundwater bypass drainage”, 7 April 2016, (in Japanese), see http://www.tepco.co.jp/nu/fukushimanp/f1/smp/2016/images2/pump_well_16040701-j.pdf,
accessed 12 April 2016.
274 TEPCO, “Current conditions of subdrain and other water treatment facilities”, 31 March 2016, (in Japanese),
see http://www.meti.go.jp/earthquake/nuclear/decommissioning/committee/osensuitaisakuteam/2016/pdf/0331_3_1h.pdf,
accessed 12 April 2016.
Mycle Schneider, Antony Froggatt et al. 90 World Nuclear Industry Status Report 2016