Heightened discharges as pump truck arrives

Heightened discharges as pump truck arrives

22 March 2011

ORIGINALLY PUBLISHED: 1.08pm GMT 
UPDATE 1: 4.01pm GMT, Connection of power to unit 3 
  
Discharges to sea from Fukushima Daiichi have shown increased levels of radioactivity, Tepco has reported, as it brings in a concrete pumping truck to secure water levels in used fuel ponds.

Tokyo Electric Power Company released the results of a half-litre sample of water taken 100 metres south of the discharge channel from damaged units 1 to 4.

Testing for a range of radionuclides showed amounts below regulatory limits for cobalt-58, iodine-132 and caesium-136. Detections were far above limits, however, for caesium-137, caesium-134 and iodine-131.

Local people began evacuation more than ten days ago and this is complete to a 20 kilometre radius. People in a further ten-kilometre zone have been warned to stay indoors. Pills to block the potential negative health effects of iodine-131 have been distributed to evacuation centres.

Iodine-131 has a half-life of eight days, so its potential danger reduces relatively quickly. Caesium-137 has a half life of 30 years, whereas the other isotope, caesium-134, has a half-life of two years. Additional monitoring at eight locations is to be carried out by the Japan Agency for Marine-Earth Science and Technology in conjunction with the Japan Atomic Energy Agency. Results from this are expected on 24 March.
  
Major pump begins work

At 5.17pm today efforts to refill fuel ponds at units 3 and 4 were upgraded significantly by the arrival of a concrete pumping truck of the kind usually used in construction. It will supply water at up to 160 tonnes per hour through a 58 metre flexible boom via remote control.

It is hoped that this extra reach, capacity and flexibility will enable Tepco to reduce issue of fuel pond levels and cooling until such time that normal systems can be brought back into operation.

External power connections have been made to units 1 and 2 and checks are underway to verify that systems will function when power is restored. A connection has been made for units 3 and 4 and cabling to the main power control centre has been completed.

Smoke

White smoke was seen rising from the broken reactor buildings of units 2 and 3 yesterday, causing a short-term evacuation of workers from around unit 3 to a safer area of the site.

Smoke at unit 2 has now reduced virtually to the point of invisibility, while at unit 3 it changed from grey to white and is dissipating. Tepco said that neither its monitoring of unit 3's reactor system or radiation in the area showed nothing unusual.

Casualties among power plant workers Two Tepco employees have minor injuries. Two contractors were injured when the quake struck and were taken to hospital, one suffering two broken legs. A Tepco worker was taken to hospital after collapsing and experiencing chest pains. A subcontract worker at an "important earthquake-proof building" was found unconscious and was taken to hospital. Two Tepco workers felt ill whilst working in the control rooms of Fukushima Daiichi units 1 and 2 and were taken to the medical centre at Fukushima Daini. Four workers were injured in the hydrogen explosion at Fukushima Daiichi 1. They were all taken to hospital. Eleven workers (four Tepco workers, three subcontract workers and four members of Self Defence Force) were hurt following a similar explosion at Fukushima Daiichi 3. They were transferred to the Fukushima Daini plant. One of the Tepco employees, complaining of pain in his side, was later transferred to hospital. The whereabouts of two Tepco workers, who had been in the turbine building of Fukushima Daiichi unit 4, is unknown.  Only one casualty has been reported at the Fukushima Daini plant. A worker in the crane operating console of the exhaust stack was seriously injured when the earthquake struck. He subsequently died. Contamination and radiation cases One Tepco worker working within the reactor building of Fukushima Daiichi unit 3 during "vent work" was taken to hospital after receiving radiation exposure exceeding 100 mSv, a level deemed acceptable in emergency situations by some national nuclear safety regulators. Another six Tepco workers have since received radiation doses in excess of the usual 100 mSv emergency allowance. One has received more than 150 mSv. Nine Tepco employees and eight subcontractors suffered facial exposure to low levels of radiation. They did not require hospital treatment. Two policemen were decontaminated. An unspecified number of firemen who were exposed to radiation are under investigation.

Researched and written
by World Nuclear News