DOE/ORO/2327 Oak Ridge Reservation Annual Site Environmental ...

Annual Site Environmental Report
Fig. 3.21. Relative levels of U-233/234 in discharges from outfalls 158, 160, 170 and the
K-1420 pad.
(Tables 3.13, 3.14, 3.15, and 3.16) indicates that total uranium results collected as part of the FY 2009
SWPP Program are within the range of historical results.
Gross alpha radiation was detected in the runoff from the K-1420 pad at levels greater than the MCL
of 15 pCi/L (Fig. 3.19). However, the levels of gross alpha radiation were, in almost all cases, much lower
than levels observed in the storm water outfalls associated with the pad. The acceptable dose rate in
surface water for piscivorous wildlife is 100 mrad per day. The total uranium activity on the slab that will
result in a 100 mrad per day dose in Mitchell Branch is 2600 pCi/L.
Analytical results collected since April 2007 (Table 3.16) indicate that
total uranium concentrations are two orders of magnitude below the 2600
pCi/L level. Therefore, it can be concluded that the K-1420 pad is no
longer a significant contributor of radioactive contaminants to the storm
drain system.
In April 2010, approval was granted by TDEC and EPA to
discontinue monitoring of the K-1420 pad.
3.5.1.4 Radiological Monitoring of Storm Water Discharges
The ETTP conducts radiological monitoring of storm water
discharges to determine compliance with applicable dose standards. It
also applies the ALARA process to minimize potential exposures to the
public. Sampling for gross alpha and gross beta radioactivity, as well as
specific radionuclides, is conducted periodically as part of the SWPPP sampling efforts. In 2009, new
radiological sampling results were obtained for four storm water outfalls (Table 3.17). These results were
used with radiological results for other storm water outfalls from other years, along with calculated flows
based on rain events in 2009, to
Table 3.17. Storm water
sampling for radiological
discharges, a 2009
Storm water
outfall
Date
sampled
100 06/29/09
292 06/10/09
350 07/13/09
430 06/10//09
a Including gross alpha,
gross beta, transuranics
( 237 Np, 238 Pu, and 239/240 Pu),
U isotopic, and 99 Tc.
Table 3.18. Radionuclides
East Tennessee Technology Park 3-39