New safety measures

January 21, 2012

NRA drafts tightened nuke plant safety rules

http://www.japantimes.co.jp/text/nn20130121x3.html

Kyodo

The Nuclear Regulation Authority presented a draft outline Monday of new safety measures to prevent or minimize the consequences of severe atomic plant crises.

Among other features, the NRA said utilities will be required to build a special safety facility housing a secondary control room for reactor operations to protect reactors against natural disasters and acts of terrorism, such as the intentional crashing of an aircraft into a nuclear plant.

The new safety standards are expected to come into force in July, replacing the current ones, which the triple-meltdown disaster that erupted in March 2011 at the Fukushima No. 1 plant proved were insufficient.

Adopting the new safety standards is a major precondition in order for utilities to apply for government permits to restart their idled reactors.

In the Fukushima crisis, triggered by a huge earthquake and tsunami on March 11, 2011, three reactors suffered core meltdowns because their key cooling systems failed due to complete station blackout.

A series of hydrogen explosions followed, resulting in massive radioactive fallout.

Before Fukushima, authorities left it up to each utility whether to take steps against the possibility of a major calamity, based on the assumption such disasters are extremely unlikely.

But new safety measures will become mandatory under the forthcoming standards.

The draft also calls for the installation of vents with filters that are able to reduce the amount of radioactive substances ejected in the event the reactors must undergo emergency venting. The Fukushima complex had venting systems but not with radiation-screening filters.

Utilities will also be told to prepare emergency power sources to ensure reactors stay cool, even during a prolonged blackout.

In addition to these new measures, the NRA is crafting new safety criteria to deal with natural disasters such as earthquakes and tsunami.

Requirements to be included in the new regulations are drawing attention because they could affect unpopular plans to restart the idled reactors.

Only two reactors are currently online, at Kansai Electric's Oi power plant in Fukui Prefecture.

See also:

Japanese nuclear regulators present new safety measures

http://mainichi.jp/english/english/newsselect/news/20130121p2g00m0dm055000c.html

Gist of new safety standards proposed for reactors

      http://www3.nhk.or.jp/daily/english/20130121_23.html

Japan's Nuclear Regulation Authority has drafted an outline of new safety standards for nuclear power plants. The new rules are expected to ensure that the country's nuclear power plants can withstand severe accidents like the one at the Fukushima Daiichi plant.

One of the proposed measures is a vent system equipped with filters to reduce levels of radioactive exhaust in case of an accident. The lack of such a system led to a massive radioactive leak at the Fukushima plant.

Another requirement being considered is a powerful water injection facility that could cool a damaged reactor from a safe distance. Such a system would be helpful in the event the reactor's building is heavily damaged by a plane crash, for instance.

The authority has also proposed that alternative control rooms to monitor reactors be built away from the reactor buildings. This would reduce the risk of plant workers being irradiated in an emergency.

Some of these measures would involve a major revamp. The panel has yet to discuss the urgency of each measure or decide on how long certain measures can wait.

Part of the new standards will be used as criteria from July for restarting nuclear plants that are currently off-line.

The nuclear regulatory body presented the outline to a panel on Monday. It will compile the final draft by the end of this month which will then be reviewed by the public. The authority is expected to announce the new standards by July.