Adding context to Japan’s (correct) decision to dispose of Fukushima wastewater

April 13, 2021, 6:28AMNuclear News
A current picture of the Fukushima nuclear power station with the more than 1,000 water storage tanks on site. Photo: Courtesy of TEPCO.

The Japanese government will soon announce the decision to dispose of stockpiled Fukushima wastewater into the Pacific Ocean, according to an AP News story published last Friday. The decision is years in the making and follows the guidelines from a panel of government-appointed experts named the Subcommittee on Handling of the ALPS-Treated Water (ALPS Subcommittee).

The dilemma: Plant owner Tokyo Electric Power Company (TEPCO) is currently storing around 1.2 million cubic meters of treated wastewater in more than 1,000 large storage tanks at the Fukushima site. This wastewater has been in the spotlight for the past few years since current projections show that storage capacity will run out by 2022. The spotlight has intensified over the past year partly because the ALPS Subcommittee issued a comprehensive report reviewing the best options to dispose of the wastewater. The ALPS Subcommittee noted that “the topic of how to handle the treated water is one of the most important decommissioning tasks, which has been discussed since 2013.”

This issue continues to plague the clean-up efforts for one reason: a failure to effectively communicate about the low risk involved with processing, diluting, and discharging the water over a period of several years—a problem exacerbated by articles published by news organizations without providing the context behind these decisions.

News coverage: Communication of the issue has left many in the community discouraged, fighting an uphill battle against misinformation and half-truths. Friday’s AP story does not state anything incorrectly, but leaving out certain context (like the timeline for the disposal and the treatment processes in place) provides the reader with an incomplete picture of the decision recommended by the ALPS Subcommittee and endorsed by the International Atomic Energy Agency and ANS. The opening is a clear example, “The Japanese government has decided to dispose of massive amounts of treated but still radioactive water stored in tanks at the wrecked Fukushima nuclear plant by releasing it into the Pacific Ocean.” The article does not clearly state that this release will take many years to complete in order to sufficiently dilute the water to keep the radiation exposure to well below background radiation levels.

Further, AP’s reporting gives only barest mention of the sophisticated water treatment processes in place at the Fukushima nuclear power station, calling the water “treated” but misleadingly stating that “radionuclides selected for treatment” can be removed. In truth, multiple treatment processes remove over 60 radionuclides and leave only tritium at levels above current regulations. As discussed in the March issue of Nuclear News, TEPCO has managed millions of tons of water either from groundwater accumulating in buildings or from the coolant water continuously injected into the three damaged cores in the decade since the accident occurred.

A depiction of the multiple water treatment facilities on the Fukushima Daiichi site. Image: Courtesy of TEPCO

Wastewater treatment at Fukushima: The water requires constant processing to remove contaminants like cesium and strontium, along with other radioactive nuclides. To complete this process, TEPCO uses two initial cesium-removal systems named Kurion and SARRY, which remove 99.99 percent of cesium, followed by a desalination system that purifies the water to be reused as coolant. The waste from the desalination process is then moved to storage tanks to be processed by a further system, the advanced liquid waste processing system (which is where “ALPS-treated water” gets its name).

Overall, these advanced systems remove 62 radionuclides such as cesium-134, cesium-137, strontium-90, and iodine-129 from the highly radioactive water. The process is so effective that the resulting levels of these radionuclides in the water are well below international regulatory standards.

Although the ALPS process removes most of the dangerous isotopes, it cannot remove one: tritium. However, tritium is “considered one of the least harmful radionuclides,” according to the Health Physics Society. Tritium levels in the treated storage tank water, according to TEPCO, are at levels higher than regulatory limits allow. However, operating nuclear power plants all over the world dilute and discharge tritiated water into the environment over a period of time as a matter of course—all under the strict supervision of regulatory bodies.

Paul Dickman, an ANS member and the study director for the ANS Special Committee on the Fukushima Daiichi accident, said that the level of radioactivity is a lot, but “the United States discharges almost double that amount from our nuclear reactor fleet every year, and South Korea annually discharges an amount equal to about 40 percent of the stored tritium at Fukushima.”

ANS’s position: Back in March 2020, ANS expressed support for the Japanese strategy, which includes a step to re-treat the wastewater before dilution and release into the ocean—further nuance omitted from the recent AP report. The ANS statement said, “If the current recommendations are followed, then the public exposure from the release of the repurified and diluted water would be many orders of magnitude less than the exposure from natural radiation per year.”

The safest option for dealing with Fukushima’s wastewater problem is clear: continue with the recommendations from the ALPS Subcommittee (and many other professionals and nongovernmental organizations) to re-treat, dilute, and discharge the treated wastewater.

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