Japan orders extra nuclear safety step as aftershocks jolt

TOKYO, April 11 (Reuters) – Japan has ordered nuclear plant
operators to put in place new safety measures by April
28 in addition to steps imposed late last month that are soon
due for checks by authorities to confirm implementation, the
trade ministry said, as another series of aftershocks
on Monday jolted the eastern region.

There has so far been no serious damage reported at five
nuclear plants in northeast Japan, including the crippled
Fukushima Daiichi plant, as a result of Monday’s magnitude-6.6
earthquake. [ID:nL3E7FA058]

The order came after a 7.4 magnitude aftershock on Thursday,
the biggest since the deadly March 11 quake, had temporarily
disabled all three power lines supplying offsite power to Tohoku
Electric Power Co’s Higashidori plant, which has been
shut for regular maintenance since February.

The ministry’s Nuclear and Industrial Safety
Agency (NISA) on Saturday ordered nuclear power companies to
install at least two emergency diesel engines even at reactors
that are not in operation and are kept at low temperatures, such
as at the Higashidori plant.

Previously, one emergency power source had been required to
be ready for use at reactors under such conditions, while only
reactors that are in operation or are shut but not fully cooled
down had been required to have two or more power sources.

All reactors, whether being operated or shut for
maintenance or other reasons, need power to run their cooling
functions for fuel rods located in pressure vessels and
spent-fuel pools.

Aiming to avoid a repeat of the tsunami-triggered crisis at
the Fukushima Daiichi plant, the ministry on March 30 ordered
nuclear plant operators to take immediate steps to improve
emergency preparedness. [ID:nL3E7EU110]

NISA by Friday accepted their reports marking the completion
of the March 30 safety requirements at their plants except for
the Fukushima complex.

(Reporting by Risa Maeda; Editing by Chris Gallagher)

Japan orders extra nuclear safety step as aftershocks jolt