IAEA Director General Yukiya Amano arrived in Japan on Sunday for extensive briefings by the Tokyo Electric Power Co. (TEPCO) officials and to visit the Fukushima Daiichi nuclear plant to see how the reactors are being cooled down.
Amano will identify ways for the IAEA to cooperate with Japan in containing the situation and will also check the progress of the "road map" drawn up by the Tokyo Electric Power Company.
He will also meet with Japanese Prime Minister Naoto Kan and other senior-level officials to discuss the outcomes of the June 2011 Ministerial Conference on Nuclear Safety, including the initiatives to improve global nuclear safety. In his meetings, Director General Amano will emphasize the IAEA's resolve to continue to offer support to Japan in mitigating the consequences of the Fukushima accident.
Stable cooling of reactors achieved at Fukushima-Daiichi
The Japan Atomic Industry Forum reports that temperatures at the bottom of Fukushima Daiichi reactor 1 have remained below 100 degrees Celsius for six consecutive days through July 24.
TEPCO says it achieved the lowered temperature by raising the amount of water injected into the reactor and that the company has begun implementing step 2 of its recovery plan for the reactors, which includes maintaining temperatures at the bottom of reactors 1, 2 and 3 below 100 degrees Celsius. TEPCO began using a new circulatory water injection system late last month and the stable operation of the circulatory water injection system is crucial to achieving that goal.
The main goal of the work being carried out at the plant, which was hit by an earthquake and tsunami on 11 March 2011, is establishing stable cooling and bringing the reactors to a state of cold shutdown.
Nuclear stress tests
To reassure the public of the safety of its nuclear power plants, Japan's nuclear regulator has instructed power utilities to carry out additional safety tests on their nuclear plants. The tests, divided into two stages, will involve simulations to gauge nuclear reactor resilience to earthquakes, tsunamis and other events beyond their current designed capacity, as well as to a loss of electricity and cooling systems.
The primary tests will assess main safety systems and whether they could be damaged or knocked out by natural disasters beyond the plant design basis. This should identify the magnitude of events that could cause damage to nuclear fuel, as well as any weak points in a reactor’s design.
The second stage will consider even more severe events and will center on a sequence of potential accidents that would make it impossible to avoid a serious accident. This stage will focus on the fundamental safety systems that were disabled by the March 11 tsunami, which lead to the Fukushima accident. This secondary analysis needs to be carried out by the end of the year and the results will be considered by the Nuclear and Industrial Safety Agency as well as the Nuclear Safety Commission.
Source:CNSC