Fourth Quarter 2005
INL Quarterly Site Environmental Report
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An array of thermoluminescent dosimeters (TLDs) is distributed throughout the Eastern Snake River Plain to monitor for environmental radiation (Figure 13). TLDs are changed out in May and again in November after six months in the field. The results of the fall sampling of TLDs exposed from May to November 2005 are discussed below.
Figure 13. TLD sampling locations.
Similar to the low-volume air results the environmental dosimeter locations are also divided into Boundary and Distant groupings. Boundary average exposure rates ranged from a low of 0.29 mR/day at Birch Creek and Blue Dome to a high of 0.37 mR/day at Arco. The overall Boundary average was 0.33 mR/day. The Distant group had a high of 0.40 mR/day at Rexburg and a low of 0.29 mR/day at the Dubois location. The overall average Distant value was also 0.33 mR/day. There was no statistical difference between Boundary and Distant locations. In addition, all values are consistent with past readings. Table 4 lists the range and average for both groups over a six-month period. All results are listed in Appendix C, Table C‑12.
Table 4. TLD Exposures from May 2005 to November 2005.
|
|
Total Exposurea |
|
|
Location |
Boundary |
Distant |
|
Average |
59.9 |
61.1 |
|
Maximum |
67.1 |
75.1 |
|
Minimum |
52.5 |
53.3 |
|
a All values shown are in milliRoentgens (mR). |
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