Deficient nuclear evacuation planning

Fukushima Today

In September 2012, the government of Japan replaced the Nuclear and Industrial Safety Agency and the Nuclear Safety Commission with the Nuclear Regulation Authority. The NRA set about at once to formulate the Nuclear Emergency Preparedness and Response Guidelines (below, “the Guidelines”), which would serve as the country’s basis for nuclear emergency preparedness and response.

The previous guidelines had called for an Emergency Planning Zone (EPZ) with a radius of about 8 to 10 km, but that was replaced with the concept of the Precautionary Action Zone (PAZ, radius 5 km) and the Urgent Protective action planning Zone (UPZ, radius 30 km). Based on the new Guidelines, local governments in the 30 km UPZ are required to develop their own nuclear emergency preparedness and response plans, including wide-area evacuation plans.

Unfortunately, the Guidelines, and the local evacuation plans required therein, do not show that much had been learned from the Fukushima Daiichi power plant accident of 2011, and do not actually protect residents from radiation exposure. 

No assurances the plans will work

Evacuation plans should really be the last resort to protect residents in the event of a major accident when a nuclear plant’s cooling functions have failed and radioactive materials could be released. Despite this, nuclear power plants are not legally required to have an effective evacuation plan in place to get approval to operate, and no framework is in place for independent audits of plan effectiveness. When a nuclear plant operator applies for permission for changes in an installation in order to restart the reactors, one would expect that evacuation plans should be included in the review by the Nuclear Regulation Authority.

Currently the Nuclear Regulation Authority just writes the Guidelines, and the real work of developing evacuation plans is left completely up to local governments in the 30 km radius of a plant. As a result, the contradictions and impracticalities of the Guidelines end up being left for local governments to deal with, and they are forced to somehow cobble together their own evacuation plans.

Unable to handle complex disasters

The current Guidelines and evacuation plans do not address “complex disasters” that involve more than one disaster at a time. Examples could include a simultaneous nuclear and natural disaster, such as an earthquake, tsunami, typhoon, or heavy snowfall.

One thing is clear. The plans rely too much on sheltering in place (literally, “indoor evacuation”). Outside the 5 km radius, the instructions are to shelter in place as long as the airborne exposure is not too high. Even within the 5 km radius, persons who would need assistance due to higher potential health risk from evacuation are instructed to shelter in place. It is also easy to imagine cases in which sheltering in place is impossible. For example, if the home has collapsed in an earthquake, there are dangers from repeated aftershocks, or there is the risk of a tsunami, a typhoon, or flooding. Furthermore, some evacuation routes are along the shoreline, and others call for escape by boat, but these routes could be impractical in bad weather.

Scope of evacuation plan formulation

The requirement to write an evacuation plan rests with municipalities within 30 km of a nuclear plant. But is this distance appropriate? For example, in the Fukushima Daiichi accident the village of Iitate had to fully evacuate. It is located about 45 km from the nuclear plant. In Fukushima City as well, more than 50 km from the accident, air dosage rates of over 20 microsieverts per hour were measured, which is the level designated for evacuation within one week. This suggests that evacuation could be necessary even outside the 30 km radius.

The flow of the radioactive plume after the Fukushima Daiichi accident was affected by wind direction and land topography, covering an extensive area in eastern Japan. The impacts of radiation exposure depend not only on distance, but also other factors such as the scale of the nuclear disaster, and topography. There are some serious problems with the fact that a line was simply drawn at 30 km, ignoring those other factors.

When the Guidelines were being drafted, an early version mentioned that a Plume Protection Planning Area (PPA) would be considered, but somehow any further mention of it completely disappeared.

Criteria for evacuation too stringent

Under the Guidelines, even if a plant has a complete loss of power as a nuclear accident progresses or emergency cooling systems for the reactor core fail, only the PAZ residents (within 5 km) are expected to evacuate, while UPZ residents (5 to 30 km) are, in principle, expected to shelter in place. Residents in the UPZ are expected to evacuate (immediate evacuation) at over 500 microsieverts per hour (Operational Intervention Level, OIL 1), or at a continuous 20 microsieverts per hour (temporary relocation within one week).

However, those levels are too high. OIL 1 is a high level of exposure during normal times, reaching one millisievert per year, which is the limit for public exposure over the course of two hours.

During the Fukushima Daiichi nuclear accident, evacuation orders were issued the evening of March 12, the day after the accident, for a radius of 20 km. Had OIL 1 or OIL 2 been in place at the time, evacuation orders would probably not have been issued quickly.

In a situation where dosages are rising rapidly, is it certainly not appropriate to make residents shelter in place until their dosages are elevated and only then have them evacuate — at least, not from the perspective of protecting residents from radiation exposure.

Problems with distributing/administering stable iodine

Radioactive iodine released from a nuclear accident concentrates in the thyroid once it is absorbed into the body through inhalation or ingestion, and can potentially cause thyroid cancer. One effective way to prevent this is to administer stable iodine prophylaxis (typically in tablet form). For this to work, timing is of critical importance. Manuals by the Nuclear Regulation Authority say that by administering it between 24 hours prior to exposure and two hours after exposure, more than 90% of the accumulation of radioactive iodine in the thyroid can be prevented.[1]

However, while stable iodine prophylaxis is distributed in advance to people in the PAZ (within 5 km), for the UPZ it is stored in public facilities near evacuation routes. For the latter, the instructions are for municipal personnel to distribute the prophylaxis to residents as they are evacuating, and even then to do so only after receiving instructions from the Nuclear Regulation Authority.

As stated above, UPZ residents will be doing immediate evacuation only when air dose reaches 500 microsieverts per hour, so they will be evacuating in the midst of exposure levels that are already quite high. It is impossible to “administer prior to exposure.” And in the confusion during evacuation, it is questionable whether residents will be sure of receiving the prophylaxis, and even then, whether verification and explanations will be done properly.

There is also some debate about the suitable age for distributing stable iodine prophylaxis. Prior to the Fukushima Daiichi accident, it was not being distributed to persons aged 40 years and over as it was not believed to be effective above that age. However, it was reported at the Subcommittee on Radiation Medicine at the Nuclear Safety Commission that research[2] had identified a significant increase in thyroid cancer risk even for persons aged 40 and above in Hiroshima, Nagasaki, and Chernobyl, so that age limit was temporarily removed. When the manual was revised in July 2019, the draft text said “There is no need to administer stable iodine prophylaxis to persons aged 40 and over.” However, citizens’ groups pointed out that the wording of the referenced documents had been changed.[3] After the public comment process, the manual’s final version was revised to say “There is little need to administer stable iodine prophylaxis to persons aged 40 and over.”

Sheltering in place does not prevent internal radiation exposure

The government directs attention to sheltering in place rather than evacuation, asserting that “indoor evacuation” can prevent radiation exposure and advertising that “sheltering in place is the first step to safety.”

However, estimates about sheltering in place published in March 2021 by the Minister of State for Nuclear Emergency Preparedness and the Japan Atomic Energy Agency suggest that staying in a typical home in a nuclear emergency will not prevent internal radiation exposure.[4] These estimates state that “based on assessments of the exposure dosage reduction effects of sheltering in place, indoor evacuation in a room in a reinforced concrete building with positive internal air pressure can reduce exposure by more than 90%.” Having positive pressure involves injecting air into the building using systems equipped with filters to increase the air pressure indoors, thereby reducing intrusion by radioactive substances. This could reportedly cost about 200 million yen (just under two million U.S. dollars) per facility.

However, if the body’s internal radiation exposure is rated a value of 1 while outdoors, in a typical house without positive air pressure the exposure is only reduced to 0.67, even in an airtight house. In other words, this means that sheltering in place really only reduces exposure by about 30%.

Petition submitted to Ibaraki Prefecture and Mito City about wide-area evacuation plan for Tokai Daini nuclear plant  

In October and November 2020, FoE Japan jointly submitted a petition to Ibaraki Prefecture and Mito City about the wide area evacuation plan for the Tokai Daini Nuclear Power Plant. It was submitted jointly with citizens’ groups from Ibaraki Prefecture, including the Ibaraki Group on Nuclear Disaster Preparedness and Prevention and the Citizen’s Group to Monitor Nuclear Power Regulations.

The petition said that to facilitate wide-area evacuation during a pandemic, it is crucial to have extra measures in place to avoid crowding, such as testing centers, evacuation centers, and vehicles for evacuation. The petition stated that until plans are revised to incorporate such matters and their effectiveness is confirmed, there should be no discussions about the restart of nuclear reactors.

The authorities in Ibaraki Prefecture acknowledged that current evacuation plans to not address pandemic concerns, and said that going forward, they will promote the necessary changes and listen to citizen concerns.

In Mito, Mayor Takahashi Yasushi received the petition, acknowledged that “new issues have arisen due to COVID-19,” and said “I cannot agree to the restart of nuclear reactors unless we get citizen support for the evacuation plans.”  

Misawa Michiko, representing the Ibaraki Group on Nuclear Disaster Preparedness and Prevention, presenting petition to Mayor Takahashi Yasushi of Mito City.

[1]Nuclear Regulation Authority, “Distributing and administering stable iodine prophylaxis” (revised 3-Jul-2019) (in Japanese).

[2] Yoshio Hosoi, Research Institute for Radiation Biology and Medicine, Hiroshima University (January 12, 2011), “The risk of thyroid cancer when the age at exposure is 40 years or older,” Subcommittee on Radiation Medicine, Nuclear Safety Commission.

[3]The WHO 2017 guidelines stated that “children, adolescents and pregnant and lactating women are most likely to benefit from stable iodine, but the benefit may be lower for those over 40 years of age,” but this was incorrectly quoted as “little benefit is expected from taking stable iodine for those over 40 years of age.” Pointed out by citizens’ groups such as the Kansai Network Concerned about Evacuation Plans and the Citizens’ Group to Monitor Nuclear Regulations.

[4] Radiation Protection Policy Planning Division, Nuclear Regulation Authority (March 2020), “Protection measures during a nuclear disaster: Sheltering in place in facilities equipped for radiation protection measures” (provisional version) (in Japanese).