Nuclear Energy Institute Report on Japan’s Nuclear Reactors, March 25, 2011 (1:30 PM EDT)

Washington, D.C.–(ENEWSPF)–March 25, 2011 – UPDATE AS OF 1:30 P.M. EDT. 
Workers have switched from sea water to fresh water to cool reactor 1 and were expected to make the same change for reactors 2 and 3 at the Fukushima Daiichi nuclear power plant by Saturday. Pressure and temperature inside reactor 1 were declining on Friday.

Lighting has been restored in the control rooms of reactors 1 through 4 at the plant, which lost electric power after the March 11 earthquake and tsunami, the Japan Atomic Industrial Forum said. With offsite electric service connected to all the units, workers are attempting to connect plant safety equipment. Some pumps and other equipment that were damaged in the earthquake and tsunami must be repaired or replaced.

Water spraying to maintain cooling of used uranium fuel rods in the reactor 3 used fuel storage pool was suspended because of high radiation levels near that building, but spraying into the reactor 1 and 4 storage pools continued.

Reactors 5 and 6 are safely shutdown and are being cooled with pumps using offsite electricity.

Radiation dose rates at the Fukushima Daiichi site boundary continue to range from 1 millirem to 3 millirem per hour.

Japanese officials are investigating the source of higher radiation readings at reactor 3 at the Fukushima Daiichi nuclear power plant after two workers were contaminated while laying cable in the turbine building. Tests of the water in which the workers were standing contained a concentration of radioactive material many times the level normally found in water circulating in the reactor, the Nuclear and Industrial Safety Agency said.

“When we looked into the composition of the water, the source…seems to be the reactor core,” said NISA’s Hidehiko Nishiyama. “Another possibility is the spent fuel, and we cannot rule out that possibility either.”

Several possibilities could account for the presence of radioactive materials in the turbine building. Seawater sprayed onto the fuel pool area may have washed over the floor of the fuel pool area onto the turbine building and leaked through the damaged roof into the basement of that building. Other possibilities include a problem with an interconnected system to the primary containment, such as the main steam system, or a small opening in the reactor containment structure.

Japanese authorities recommended residents within 30 kilometers of the plant evacuate voluntarily, extending the recommendation from 20 kilometers. Damage to infrastructure in the area from the earthquake severely limits the ability to provide water, food and other necessary supplies to people sheltering in their homes for the coming weeks.

Tokyo Electric Power Co. is stepping up efforts to switch from sea water to fresh water for cooling the reactors and used fuel storage pools. The United States government has urged the switch to fresh water as soon as possible and is providing two U.S. Navy barges, each of which can carry up to 1,000 tons of water. The ships are scheduled to reach port about 60 kilometers from the Daiichi plant in about three days. Japanese workers at the site will install pipes and hoses to carry the water to the plant.

New Web Page on ‘Health and Radiation’

NEI has created a new web page, “Health and Radiation Safety,” which provides information and links to additional resources.