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ENVIRONMENTAL RADIATION

An array of thermoluminescent dosimeters (TLDs) is distributed throughout the Eastern Snake River Plain to monitor for environmental radiation (Figure 14). TLDs are changed out in May and again in November after six months in the field. The results of the spring sampling of TLDs exposed from November 2003 to May 2004) are discussed below.

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 Blue Dome to a high of 0.37 mR/day at Atomic City. The overall Boundary average was 0.34 mR/day. The Distant group had a high of 0.38 mR/day at the Rexburg CMS and a low of 0.27 mR/day at the Jackson, Wyoming location. The overall average Distant value was 0.33 mR/day. There was no statistical difference between Boundary and Distant locations.

Furthermore, 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 11.

Table 4. TLD Exposures from December 2003 to May 2004.

 

Total Exposurea

Location

Boundary

Distant

Average

61.1

59.6

Maximum

67.8

68.0

Minimum

52.5

49.3

a      All values shown are in milliRoentgens (mR).

 

Figure 14. TLD sampling locations.

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