Tepco Releases Details Of Latest Radiation Readings
Written by NucNet
Wednesday, 03 August 2011
The operator of the Fukushima-Daiichi nuclear power plant in Japan says it has detected hot spots with the highest confirmed indoor level of radioactivity at the facility since the March 2011 accident.
Tokyo Electric Power Company (Tepco) said yesterday that the level near the entrance to a room forming part of the Standby Gas Treatment System (SGTS) for units 1 and 2 was more than 5,000 millisieverts per hour (mSv/hr) at 11:19 local time on 2 August 2011.
The day before at 16:00 local time, Tepco had measured a dose rate of “more than 10,000 mSv/hr” at the bottom of the common ventilation exhaust stack of units 1 and 2.
It would take only a few minutes for a person staying in such an environment to be exposed to more than 250 mSv of radiation – the legal limit for nuclear workers in emergency situations.
The SGTS moves air from the reactor buildings to the environment through a series of filters, ultimately releasing it through the exhaust stack. It also provides a route from which excess pressure can be released by venting.
Tepco restricted access to the areas, saying it will consider measures to reduce the radioactivity and that it has no immediate plans for any operations there.
Tepco said the radioactivity was the result of pipes running through the SGTS room that were used to vent air containing radioactive substances from the reactor on 12 March 2011.
Tepco had previously detected a maximum of 1,000 mSv/h outdoors in debris, and a maximum of 4,000 mSv/hr indoors in one of the reactor buildings.
