1.23 million tons of Fukushima nuclear sewage will be discharged into the sea?
Expert: Please slow down, wait for the pace of scientific research
◎Reporter Li He
Regarding the nuclear sewage stored in the Tokyo Electric Power Fukushima Daiichi Nuclear Power Plant, the Japanese government has basically determined to dispose of it in the form of putting it into the ocean, and it will hold a cabinet meeting and make a formal decision on April 13 at the earliest.
According to reports, Tokyo Electric Power has prepared a total of about 1,000 water storage tanks, 90% of which are currently full.
The total capacity of all water storage facilities is approximately 1.37 million tons, which is expected to reach its limit in the fall of 2022.
In this regard, the international environmental protection organization Greenpeace strongly condemned.
On April 12, Kazuki Suzuki, director of the Climate and Energy Program of the Greenpeace Japan Office, said in an interview with a reporter from the Science and Technology Daily that if the cabinet of the Japanese government makes a formal decision, more than 1.23 million tons of nuclear radiation wastewater will be stored at the Fukushima Daiichi Nuclear Power Plant. If it is discharged into the Pacific Ocean, this is a decision that ignores the ecological environment.
"It not only disappoints the residents of Fukushima again, but also exposes the residents living in the surrounding and Pacific Rim areas to the risk of nuclear radiation. Although Japan has the technology and conditions to build more unmanned areas where the Fukushima Daiichi nuclear power plant is located and the surrounding area. More long-term storage tanks can to a certain extent control the risk of nuclear radiation proliferation to a minimum. However, the government cabinet has chosen the most cost-effective way-dumping nuclear sewage into the Pacific."
In view of the large amount of waste water and high tritium concentration after the Fukushima nuclear accident, Liu Xinhua, chief expert of the Nuclear and Radiation Safety Center of the Ministry of Ecology and Environment, also said in an interview with a reporter from Science and Technology Daily that the Japanese government should consider further treatment measures, including increasing waste water. Storage tanks to avoid hasty discharge and allow sufficient time for the preparation of wastewater discharge after treatment.
There is no precedent in the world for the disposal of nuclear wastewater after treatment
In 2011, there was an accident at the Fukushima Daiichi Nuclear Power Plant. It has been 10 years since the nuclear reactor ceased operation.
Liu Xinhua said that there are three main sources of radioactive waste water from the Fukushima Nuclear Power Plant: the original coolant in the reactor, the water injected to continuously cool the core after the accident, the massive amount of groundwater and rainwater that infiltrated the reactor.
"After the Fukushima accident, Tokyo Electric Power Company set up the accident radioactive waste water purification treatment equipment, including strontium cesium adsorption equipment, reverse osmosis membrane desalination equipment and multi-nuclides removal equipment (ALPS), etc., used to remove the accident radioactive waste water. Most of the radionuclides. A large number of storage tanks have been set up to store the treated and purified wastewater." Liu Xinhua said that these treated wastewater still contains radionuclides such as tritium, strontium, cesium, and iodine.
Liu Xinhua pointed out that historical nuclear accidents, such as the Chernobyl and Three Mile Island nuclear accidents, were all released into the atmosphere. There has been no nuclear accident similar to the Fukushima nuclear accident that produced a large amount of waste water. Therefore, there has been no nuclear accident after treatment. A precedent for the discharge of wastewater into the ocean.
"Currently, there is no provision for an international third-party agency to inspect and discharge nuclear wastewater after treatment, and there are no relevant inspection procedures and standards." Liu Xinhua said.
Disposal methods of wastewater discharge to the sea still need further study
According to reports, it is impossible for radionuclides to decay in a short period of time. Storage in storage tanks is not a suitable way to solve the problem of nuclear waste water. The millions of cubic meters of treated waste water stored in the Fukushima Nuclear Power Plant is a source of major safety risks, and there are earthquakes, Huge risks that may be caused by factors such as tsunamis.
Therefore, how to properly dispose of wastewater has become an urgent problem for the Japanese government to solve.
In fact, there are other ways to discharge waste water into the Pacific Ocean.
Since 2013, the Japanese government has evaluated five post-treatment wastewater treatment options including formation injection, discharge into the ocean, steam release, hydrogen release, and underground burial, and examined the feasibility and possible limitations of each option, including the duration. , Cost, scale, secondary waste, radiation exposure of staff, etc.
In February 2020, the ALPS Purified Water Treatment Subcommittee released the evaluation report of the wastewater treatment program after the Fukushima nuclear accident in Japan. It concluded that both the discharge into the ocean and the release of steam are feasible solutions.
Among them, the operation of discharging into the ocean is more convenient, and other disposal schemes are poor in terms of economy, technical maturity or time.
"There is no precedent for the disposal of waste water after nuclear accident treatment, and further research is needed for the disposal method." Liu Xinhua said that the degree of impact of waste water discharge on the marine environment depends on the type, concentration, and total amount of radionuclides discharged, as well as the specific radionuclide and The interaction of key elements of the marine environment such as sediments and marine organisms.
However, after a large amount of Fukushima wastewater is discharged into the Pacific Ocean, radionuclides will inevitably accumulate in marine sediments and marine organisms in the sea near the discharge point, and some nuclides will migrate and diffuse with ocean currents and other sea areas.
Japan is a close neighbor of our country. Regardless of whether the wastewater discharged by Japan is discharged in nearshore or ocean-going public waters, radionuclides will diffuse along the ocean currents in the North Pacific waters, and the waters under our jurisdiction will inevitably be affected by the transboundary pollution of radioactive materials.
Liu Xinhua suggested that the Japanese government should adopt waste water treatment technologies and devices with high decontamination factors to further purify and treat the excess nuclides and reduce the radionuclide content in the treated waste water as much as possible; study the treatment technology of tritium, and promptly disclose the research progress and As a result, if feasible technology is available, it should be used for the treatment of tritium in wastewater immediately.
Greenpeace suggested that in order to avoid the continuous increase of nuclear radiation pollution of wastewater, air-conditioning should be used to replace the existing water cooling when cooling nuclear fuel rod fragments; in the face of the problem of continuous groundwater infiltration, a moat should be built at the current site of the Fukushima Daiichi Nuclear Power Plant to block groundwater.