Millions of people in Japan are deeply troubled about the possibility of future cancers caused by the radioactive releases from the Fukushima Daiichi nuclear accident. Conclusions of no discernible future cancers made by the International Atomic Energy Agency, United Nations Scientific Committee on the Effects of Atomic Radiation, or the World Health Organization, have been largely ignored by this apprehensive demographic. The reason behind their rejection seems to be that the IAEA is a “promoter” of nuclear energy, and UNSCEAR and WHO are directly connected to the international watchdog. Japan’s government was a promoter of nukes before Fukushima, and a terrible accident ensued. This caused the public to lose trust in Tokyo, and by proxy distrust any international organization also assumed to promote nuclear energy.

Late in August, a prestigious expert organization not connected to the IAEA completed its assessment of the potential for cancers due to nuke accidents, including Fukushima. The Canadian Nuclear Safety Commission (CNSC) has concluded that there will be no evident increase in cancer for most of the population from radiation released in a worst-case nuclear accident. Their Study of Consequences of a Hypothetical Severe Nuclear Accident and Effectiveness of Mitigation Measures is the result of a collaborative effort to address concerns raised during public hearings on the environmental assessment for the refurbishment of Ontario Power Generation’s (OPG’s) Darlington nuclear power plant. Their hypothetical accident at Darlington included all four units at the site, making their conclusion directly applicable to the radiological aftermath of Fukushima’s four damaged units.

The study applied protective actions such as evacuation, sheltering indoors, and administration of potassium iodide pills that would be taken in the emergency situation. The exposures following protective actions were then used as inputs for a human health risk assessment. The CNSC said some evacuations would be needed in close proximity to Darlington, but evacuations beyond a 12 km zone from the station would not be required, even under the most extreme worst-case scenario.

The CNSC concluded that it would be nigh-impossible to distinguish radiation-induced cancers from those that would be expected to occur in the population. The worst case estimates revealed the increased risk of developing all cancers, leukemia, and adult thyroid cancer, from released contaminants would result in an additional 0.0004 % chance of development on top of the 49% baseline risk of developing such cancers. The only radiation-induced cancer that might be distinguished from baseline cancers was childhood thyroid cancer, with a slightly increased risk predicted for all scenarios. The estimated excess of future childhood thyroid cancers in close proximity to the plant was 0.3% above a baseline of about 1%.

Specific to Fukushima, the report says, “The overestimation resulting from [the government’s] preliminary modelling has been demonstrated following the Fukushima accident where doses estimated based on post release measurements were shown to be two to five times less than the preliminary estimated modelled doses. For additional perspective, the measured doses at Fukushima are comparable to the estimated doses in this [Darlington station] study, and international authorities have indicated an increased incidence in cancer (e.g. thyroid cancer) is unlikely to be observed in the future in Japan.” In other words, the estimated exposures used by Tokyo’s then-antinuclear Prime Minister and his cronies to justify their evacuation orders, were grossly exaggerated. In addition, claims of future cancer epidemics are not justifiable.

The CNSC notes that the lessons learned from Fukushima, including all mandated safety upgrades now being enforced by Japan’s Nuclear Regulation Authority, would further ease the worst-case predicted outcome of a four-unit accident at Darlington. The report states, “Had all of the plant-specific safety design features, operator actions and other Fukushima enhancements…been fully credited/realized, the likelihood of a severe accident would have been practically eliminated to the point where the release of radioactive material considered in this study and its impact on human health and the environment would have been significantly reduced.” The implication here is that all the safety upgrades required before restarting any nukes in Japan makes a future Fukushima-level accident very, very unlikely, if not just about impossible.

People of Japan…here are the bottom lines. An expert panel on nuclear safety, entirely independent of the IAEA, says that there will be no statistically-evident change in cancer incidence and death rates in Japan due to Fukushima Daiichi. In addition, much, if not most of the evacuated population of Fukushima Prefecture should not have been evacuated, in the first place. Finally, when all legally-required safety upgrades are made to Japanese nukes, there is no rational reason to expect another Fukushima-level accident to happen.

(Unfortunately the report itself will not be available for computer download until later this month. It will be posted on the CSNC website.)