July 2012

This Explanation of Significant Differences (ESD) was prepared to describe a change to the Brookhaven Graphite Research Reactor (BGRR)remedy described in the January 31, 2005 Final Record of Decision(ROD). The final remedy selected in the ROD included removal of the graphite pile (completed in 2010) and the bioshield, which would result in the removal of more than 99 percent of the radioactive material at the BGRR complex.

During the removal of the graphite pile and biological shield, the floor beneath the BGRR was modified. First, to cover the void spaces to prevent graphite pile debris from falling into the air intake plenums and later, to strengthen the floor to accommodate a larger excavator/hammer unit required to break the high-density concrete walls of the bioshield. As a result, a 3.25 foot section of the bioshield wall was embedded below floor level.

The change to the scope of work for the BGRR is that the bioshield wall will be removed to the existing Building 701 floor level leaving the portion of the wall below the floor in-place. The remaining wall will be encased beneath a reinforced concrete cover.

The radiological content that would remain as a result of this change was reviewed. It has been determined that there will not be a change to the overall radiological content remaining and the 99 percent removal of radioactive material will still be achieved. Also, long-term stewardship activities needed for the BGRR will not be affected.

The Final Area of Concern 9, Brookhaven Graphite Research Reactor Explanation of Significant Differences was approved by the U.S. DOE, the EPA with concurrence by the NYSDEC on July 13, 2012.

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