nuclear-news

Getting rid of Fukushima’s nuclear reactors a tortuous and dangerous task

Tepco also needs to find ways to prevent any new nuclear reaction, which could happen if the fuel is not adequately cooled during the entire process…

Japan Atomic Energy Body Sees Technical Hurdles Ahead, WSJ, By MITSURU OBE, 14 Sept 11, TOKYO—Japan’s efforts to safely dismantle the stricken Fukushima Daiichi nuclear complex is expected to be fraught with technical challenges and take more than a decade to complete, the government’s Atomic Energy Commission said Wednesday.

Removing the fuel from the spent-fuel pools and the reactors is vital to ensuring there will be no radiation leakage from the quake-ravaged facility. Experts fear that their structures might have been weakened by the heat and radiation from the damaged fuel and the large amount of seawater that was poured into them as an emergency measure to cool down the fuel.

The commission, an independent body tasked to formulate the nation’s nuclear policy, will explain to other countries about a decommissioning plan during the annual general meeting of the International Atomic Energy Agency, to be held in Vienna next Monday.

Commission chairman Shunsuke Kondo previously offered his view that it would take at least 10 years before the plant operator, Tokyo Electric Power Co., becomes ready to remove the fuel from the three damaged reactors…..

The most difficult challenge facing Tepco is how to plug leakages in the primary containment structures of the damaged reactors.

The primary containment vessels, the main shield against radiation leaks, and the reactor buildings that house them, have been damaged in part by the impact of the magnitude-9 earthquake on March 11, and also by the subsequent breakdown of the cooling systems and the overheating of the reactors. As a result, water used for cooling down the reactors has leaked out and has flooded the connecting facilities, leading to contamination of groundwater and some incidents of leakage into the Pacific Ocean.

The leakage means that the containment vessels are largely empty of water, further complicating the efforts. “Without filling up the containment vessel with water, it will be difficult to take out the toxic fuel from the reactors safely,” said Hirofumi Nakamura, senior official of the Japan Atomic Energy Agency, a government research affiliate, at the commission meeting.

Numerous technical challenges need to be solved before Tepco begins the fuel removal, Nakamura said. New robots have to be built capable of undertaking operations to probe the conditions inside the containment vessels, identify and plug the leakages, and remove the fuel, he said. Tepco also needs to find ways to prevent any new nuclear reaction, which could happen if the fuel is not adequately cooled during the entire process….

http://online.wsj.com/article/SB10001424053111904060604576570283480045452.html

September 15, 2011 - Posted by Christina Macpherson | decommission reactor, Japan