PA.15-6 - Document Request - U.S. Department of Energy

Vicinity Property No. CA-401
Outdoor gamma readings in the excavated area ranged from 11
to 13 micro R/hr. The readings are given in Table 3.2.
Drawings CA-401-020, CA-401-021, and CA-401-022 show the
actual areas of excavation.
These results confirm that exterior contamination has been
reduced to levels below the EPA standards for radium in
soil. Background for the Canonsburg site is 8 to 11 micro
R/hr and 1.2 pCi/g.
Interior:
Remedial action was performed indoors only in Building 14A
on this property. A gamma scan in the excavated regions
showed gamma levels up to a maximum of 12 micro R/hr, which
is less than the EPA standard of background plus 20 micro
R/hr. These results are described in Table 3.2.
"Grab" radon daughter concentration (RDC) measurements were
made in 4 locations, as described in Table 3.4. These
measurements were made under standard conditions as
described in the VPMIM. Measurements were not made in
Building 14A as close-up conditions cannot be met.
3.2 Recommendation for Certification
3.2.1 Exterior:
3.2.2 Interior:
Fourteen areas of contamination were identified and
removed. Soil samples after excavation and prior to
backfilling indicate that the limits of 5 pCi/g in the
surface 15 cm. and 15 pCi/g in any 15 cm. layer below the
surface are not exceeded. Based on this information, we
recommend that the exterior of this vicinity property be
certified to be in compliance with EPA standards for the
UNTRA Project.
Remedial action was conducted in the structure. All gammu
readings taken in the structure following remedial action
were less than the 20 micro R/hr above background limit.
Radon daughter concentrations are below the 0.01 WL limit
for grab samples. Based on this information, we reconmend
that the interior be certified to be within the limits of
the EPA standards for the UNTRA Project.
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