Stricter standards for evacuation discussed

December 28, 2012

Evacuation standards toughened

Kyodo

http://www.japantimes.co.jp/text/nn20121228a7.html

A Nuclear Regulation Authority panel introduced new criteria Thursday for issuing atomic crisis evacuation orders that are twice as stringent as current international benchmarks.

The new standards will be reflected in a government guideline for nuclear disaster steps.

Under the new standards, in the event of a fallout crisis involving a nuclear plant, residents outside a 5-km radius of the facility will be told to evacuate within several hours if the radiation level reaches 500 microsieverts per hour. This compares with the figure set by the Vienna-based International Atomic Energy Agency: 1,000 microsieverts.

A restriction on the consumption of food produced near a disaster-hit power plant must be issued within a few days if radiation levels hit 0.5 microsievert per hour, compared with 1 microsievert set by the IAEA.

New criteria also call for issuing temporary evacuation orders to residents in areas where the radiation level reaches 20 microsieverts per hour. The figure is lower than the international standard of 100 microsieverts.

The government will begin collecting information to gauge the effects of a powerful earthquake — intensity of lower 6 or stronger on the Japanese scale to 7 — on municipalities where nuclear plants are located.

Residents within a 5-km radius of a nuclear plant will be asked to prepare to evacuate if all power at the plant goes out for more than five minutes or if the reactor cooling system cannot be run from the control room.

The panel calls for immediate evacuation of residents when a plant operator loses the ability to shut down reactors or when pressure in reactor containers reaches the maximum allowable limit.

The NRA debuted in September as a highly independent body to replace the Nuclear and Industrial Safety Agency and Nuclear Safety Commission. NISA was hit for failing to improve the defenses of Tokyo Electric Power Co.'s Fukushima No. 1 nuclear plant, which suffered three meltdowns last year after being overrun by tsunami.

December 27, 2012

New nuclear evacuation standard to be delayed

http://www3.nhk.or.jp/daily/english/20121227_23.html

A decision on a new evacuation guideline for nuclear accidents in Japan will be delayed after experts questioned the basis of the draft guideline proposed by the country's nuclear regulatory body.

The Nuclear Regulation Authority had commissioned a panel of experts to draw up new standards based on its secretariat proposal.

The authority's draft calls for the immediate evacuation of residents within 5 to 30 kilometers of a nuclear power plant when radiation levels reach 500 microsieverts per hour. It also calls for temporary evacuation within a week in areas with radiation levels of 20 microsieverts per hour or more.

The figures are far stricter than the IAEA standards, which set 1,000 microsieverts for immediate evacuation and 100 microsieverts for evacuation within a week.
The Nuclear Regulation Authority says it proposed the stricter standards to be on the safe side.

But in a meeting on Thursday, experts voiced questions. Some said the authority had simply decided on a level half of that of international standard and this lacks a scientific basis. Others said the authority should adopt the international standard for the time being, while continuing discussions to set Japan's own standards.

As a result, the authority decided to start fresh discussions on the new standards.

The authority decided to set new rules based on actual radiation readings after authorities failed to make use of a radiation forecast system and could not evacuate residents promptly in last year's nuclear accident.