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1. FUKUSHIMA CRISIS: UNMONITORED RELEASES Preliminary Assessment of Accident Sequences and Potential Atmospheric Radiation Releases

Author:
David Albright, Paul Brannan, and Christina Walrond
Publication Date:
03-2011
Content Type:
Special Report
Institution:
Institute for Science and International Security
Abstract:
instances of unmonitored radiation releases to the atmosphere from the Fukushima Daiichi nuclear reactors. The radiation readings and ground level wind directions are from the TEPCO web site. ISIS could not validate TEPCO’s information, but the data appear adequate to conduct some scoping analysis of the releases. Using this information, ISIS has sought to understand the fate of the releases and determine whether radiation monitoring stations intersected the plume of released radioactive material. We welcome any input. Since March 11, reactor units 1-4 at the Fukushima Daiichi nuclear plant have experienced hydrogen explosions, fires, partial melting of irradiated or “spent” fuel in the reactors, the uncovering and possible burning of irradiated fuel in spent fuel ponds at reactor 4 and perhaps other reactors. Table 1 lists several known accidents that occurred through March 18. These accidents, and perhaps ones that were not noticed or reported, released significant amounts of radiation into the atmosphere that the winds spread widely. They all require greater scrutiny. From an analysis of the limited data on atmospheric releases, ISIS has developed several key findings. The first is that the limited radiation detection capabilities at the Fukushima Daiichi plant following the earthquake and tsunami eliminated the ability to detect, characterize, or track a release of radiation. Many releases went partially or completely undetected by on-site monitoring. None of the releases from accidents were monitored as to their radioactive contents. Although the amount and type of radionuclides in these releases cannot be estimated from the existing on-site monitoring data, the existing data support that the potential for significant radiation doses to off-site population exists, particularly in sectors northwest and southwest of the reactors.
Topic:
Natural Disasters, Nuclear Power, Nuclear Safety, Disaster Management, Fukushima Disaster, and Earthquake
Political Geography:
Japan and Asia

2. Characterizing the Crisis at Fukushima Daiichi Nuclear Power Station

Author:
David Albright and Christina Walrond
Publication Date:
04-2011
Content Type:
Special Report
Institution:
Institute for Science and International Security
Abstract:
During the crisis at the Fukushima nuclear power reactors following the earthquake and tsunami on March 11, 2011, the Japanese Safety Authority issued ratings for the accident on the International Nuclear Events Scale (INES). Initially, it stated that the incident was a level 4, but it subsequently raised the levels assigned to each reactor, with the majority receiving a level 5. Table 1 indicates the latest ratings issued March 18 by the Japanese authority, where it has parsed the ratings based on accidents at individual reactors. Although the radioactivity is emitted from different reactor buildings, it represents a collective hazard to public health. As such, the accident should be judged comprehensively, not only in component parts. Simply because some aspects of the crisis were not as catastrophic as others does not lessen the overall severity of the accident. ISIS continues to assess that the accident is a level 6.
Topic:
Nuclear Power, Crisis Management, Disaster Management, Fukushima Disaster, and Earthquake
Political Geography:
Japan and Asia