Authorities and IAEA have deemed process safe, but plan has faced opposition from fishing industry and neighbouring countries
Japan’s Tokyo Electric Power Company (Tepco) on Thursday (24 August) started discharging treated water stored at the Fukushima-Daiichi nuclear power station into the sea, International Atomic Energy Agency (IAEA) experts at the site confirmed.
The discharge began 13.00 local time (06.00 Central European Time), according to Tepco, the state-owned owner and operator of Fukushima-Daiichi.
The company said it expects to discharge only around 200 or 210 cubic meters of treated wastewater. From Friday, it plans to then continuously release 456 cubic meters of treated wastewater over a 24-hour period and a total of 7,800 cubic meters over a 17-day period.
Tepco said the operation would be suspended immediately and an investigation conducted if any abnormalities are detected in the discharge equipment or the dilution levels of the treated wastewater.
The start of the operation comes weeks after the IAEA approved the discharge, saying that the radiological impact on people and the environment would be “negligible”.
Over 1.3 million tonnes of water – cleansed of all its radioactive material except tritium – will be gradually poured into the ocean through an underwater tunnel.
Tritium levels will be thinned down to 1/40 of the concentration allowed by Japanese standards. Japan said tritium levels in the water will be below those considered safe for drinking under World Health Organisation (WHO) standards.
The IAEA concluded the plan for “controlled, gradual discharges of the treated water to the sea,” would have a “negligible radiological impact” on people and the environment.
Japanese prime minister Fumio Kishida pledged earlier this week that the treated water release would be conducted safely and its impact monitored closely.
Experts point out that nuclear plants around the world use a similar process to dispose of wastewater containing low-level concentrations of tritium and other radionuclides.
‘No Evidence Of Detrimental Effects’
“Tritium has been released [by nuclear power plants] for decades with no evidential detrimental environmental or health effects,” said Tony Hooker, a nuclear expert from the University of Adelaide.
“At any other nuclear site in the world, this would be considered a ‘routine’ release of treated wastewater with very low levels of radioactivity,” said Jim Smith, an environmental science professor at University of Portsmouth in the UK.
The water was largely used to cool the three damaged reactor cores, which remain highly radioactive. Some of it has since leaked into basements of the reactor buildings but was collected and stored in tanks.
Over the past two years the IAEA has conducted a review of the safety related aspects of handling and discharge of the treated water at Fukushima-Daiichi. An IAEA report concluded that the wastewater discharge is consistent with international safety standards.
IAEA experts this week took samples from the first batch of diluted water prepared for discharge.
Analysis confirmed that the tritium concentration in the diluted water that is being discharged is far below the operational limit of 1,500 becquerels per litre (Bq/l). Becquerels are a measure of radioactivity.
IAEA director-general Rafael Grossi has said the agency will continue its “impartial, independent and objective” safety review during the discharge phase.
The IAEA and Japan agreed that the IAEA will maintain a presence at Fukushima-Daiichi. The IAEA opened an office onsite in July.
The IAEA launched a webpage to provide live data from Japan on the water discharge. The data includes water flow rates, radiation monitoring data and the concentration of tritium after dilution.
Japanese authorities have described it as a necessary step in decommissioning Fukushima Daiichi some 12 years after a massive earthquake and ensuing tsunami led to a meltdown of three nuclear reactors in March 2011.
Tepco said the hundreds of tanks storing the treated water are nearly full and will reach their capacity of 1.37 million tonnes in early 2024.
How Is The Water Treated, And What Is Tritium?
The water goes through a filtration system known as Alps meant to remove radioactive elements. To reduce concentrations of tritium, a radioactive material that is difficult to separate from water, authorities will also dilute the wastewater before discharging it into the ocean.
Japanese authorities say the concentration of tritium will drop to background ocean levels after the dilution. The plan involves discharging the treated water at a maximum rate of 132,000 gallons (499,000 litres) per day.
The amount of tritium in the wastewater release is expected to be about seven times lower than the WHO drinking water limit for tritium. People are exposed to tritium in small amounts in tap water and in rain.
Tritium is a radioactive by-product of the operation of nuclear plants. It is regularly released into waterways and emits very weak radiation. It is difficult to remove from water, which is why the treated water at Fukushima-Daiichi contains tritium.
Tritium exists naturally in rainwater, tap water and the human body. Then tritium being released at Fukushima has been diluted to reduce radioactivity levels to 1,500 Bq/l. Japan’s regulatory standards allow for a maximum of 60,000 Bq/l.
Japanese authorities and the IAEA have deemed the process safe. But the plan has faced opposition from Japan’s fishing industry and neighbouring countries.
China announced on Thursday it was banning all seafood from Japan in response to Tokyo’s decision to begin releasing treated radioactive wastewater from Fukushima-Daiichi.
The water goes through a filtration system known as Alps meant to remove radioactive elements. Courtesy IAEA.
The Fukushima-Daiichi nuclear power station was destroyed by an earthquake and tsunami in 2011. Courtesy IAEA.
