Temporary Increase in the Emergency Exposure Dose Limit in Response to the TEPCO Fukushima Daiichi NPP Accident

In response to the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant, the Japanese government declared a nuclear emergency on 11 March 2011 and implemented emergency operations to prevent the accident's expansion. For prompt implementation of the operation, the Ministry of Health, Labour and Welfare (MHLW) promulgated an exemption ordinance to increase radiation exposure dose limits from 100 mSv to 250 mSv during emergency work at the affected plant. After the settlement of early-stage confusion of the accident, the MHLW had reduced the emergency dose limit back to the original limit step by step. This paper explains the decision-making process and deliberation on temporarily raising the emergency dose limit and the key challenges that require further deliberation to resolve.