TOKYO -- Japan's Nuclear Regulation Authority (NRA) did not include "complex disasters," a situation when nuclear accidents occur simultaneously with natural disasters, in its draft evacuation plans despite requests from local governments to consider the possibility, citing a lack of time to discuss all opinions.

An NRA review team is reassessing the "sheltering indoors" strategy for residents within 5 to 30 kilometers of a nuclear power plant. Six local bodies, including Ishikawa Prefecture, which was affected by the 2024 Noto Peninsula earthquake, had urged the panel to review its indoor sheltering plans on the presumption that complex disasters will occur, the Mainichi Shimbun learned through a request for information disclosure submitted to the regulatory authority.

During the Noto Peninsula quake, buildings collapsed and roads were severed around Hokuriku Electric Power Co.'s Shika Nuclear Power Station in Ishikawa Prefecture, shedding light on the potential difficulty of sheltering indoors. Although no severe accident occurred at the plant and safety was not compromised, the situation called into question the preparedness against complex disasters.

Despite these concerns, the review team compiled a draft report in February this year that did not include new measures for complex disasters, suggesting the possibility that the concerns of the local governments were not adequately reflected.

In October 2024, the panel presented an interim summary of the indoor sheltering review, including a "three-day benchmark" for staying indoors, and solicited opinions from prefectures and municipalities around nuclear power plants nationwide. About 200 comments were submitted by 38 local governments, which the NRA compiled and presented at the review team's meeting in November.

Among these, only two opinions about complex disasters were presented: one requesting mention of how residents should act, such as sheltering at schools or community centers, in cases of house collapses due to quakes, and the other asking for an easy-to-understand presentation of protective measures to residents, given that prioritizing responses to natural disasters is beneficial. No comments about the difficulty of sheltering indoors during complex disasters were presented.

However, upon obtaining all opinions through the freedom-of-information request, the Mainichi Shimbun found that six local governments had called for guidelines on evacuation during such disasters.

The Ishikawa Prefectural Government pointed out that if an earthquake or other disasters damage a nuclear plant, houses and evacuation centers could also be affected, making indoor sheltering impossible. It requested that the basic concept of sheltering indoors (including cases where building damage makes it difficult) and evacuation be reviewed and specific examples be provided.

The government of Nagaoka, Niigata Prefecture, located within 30 km of Tokyo Electric Power Company Holdings Inc.'s Kashiwazaki-Kariwa Nuclear Power Station, argued, "Without considering complex disasters, the plans would be disconnected from residents' and municipalities' concerns regarding increasingly severe and frequent natural disasters, throwing their feasibility into question. We want (the NRA) to review the possibility of a complex disaster, rather than treating it as a special case."

Although the team increased references to complex disasters in the February draft report, it maintained the conventional view of evacuating the area if indoor sheltering is not possible and did not include specific measures.

The NRA's Radiation Protection Policy Planning Division, which serves as the secretariat for the review team, revealed in an interview with the Mainichi Shimbun that only the same two opinions presented at the November 2024 open-door meeting were shown to individual team members, not all opinions.

They explained the reason for narrowing down the opinions, saying, "We created the presentation materials by organizing similar opinions and important content. There is no time to introduce and discuss all opinions. It wasn't done intentionally; it was about a matter of space."

The review team plans to finalize the report at a March 28 meeting. An Ishikawa Prefectural Government official told the Mainichi, "The regulation authority started discussions without assuming natural disasters, and it was quickly deemed unnecessary to consider indoor sheltering in the event of a catastrophe. We're not on the same page in this discussion."

(Japanese original by Harumi Kimoto, Lifestyle, Science & Environment News Department)