silo 3 - U.S. Department of Energy

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Silos Project Environmental Monitoring Plan
40000-PL-0010
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August 29, 2002
. construction activities, it may be necessary to re-locate air monitors. Changes in monitoring
locations will be documented and reviewed through the Design Change Notice (DCN) process.
The sampling and analysis program will consist of bi-weekly isotopic thorium, radium-226, and
total particulate analyses. Results from the isotopic thorium analysis (thorium-228, thorium-
230, and thorium-232) will be used to specifically monitor thorium-230, the primary isotope
of concern within the Silo 3 residues. The radium-226 analysis will be used to assess the
effectiveness of prosess-control measures during the Silo 3 and AWR projects. Total
particulate analysis will be used to determine if the results are indicative of project emissions
or reflect the measurement of fugitive emissions from other sources (e.g. dust from
construction vehicle traffic). The Project may evaluate the feasibility of changing the sample
frequency (from biweekly to weekly or monthly) based upon factors such as historical results,
the status of Silos Project activities, results from occupational particulate monitors, and the
frequency of other IEMP boundary monitors. Any proposed change to the particulate sample
analysis frequency will be documented and reviewed through the DCN process. .
Samples will be analyzed according to the requirements for Analytical Support Level (ASL) B
in the Sitewide CERCLA Quality (SCQ) assurance plan. The highest allowable minimal
detectable concentrations (HAMDCs) for ASL B are 9.0 pCi/filter for isotopic thorium analyses
and 4.0 pCi/filter for radium-226 analysis.
3.2 Direct Radiation Monitoring
In addition to airborne emissions, exposure to direct radiation is also a radiological hazard at
the FEMP, particularly in the vicinity of Silo 1 and Silo 2. Direct, (penetrating) radiation is
emitted from the radioactive materials stored onsite. The largest source of penetrating
radiation at the FEMP results from the transformation of radium-bearing materials stored in
Silos 1 and 2.
The existing IEMP environmental monitoring network includes five locations that monitor direct
radiation levels in the vicinity of Silos 1 and 2. The monitoring is conducted using
thermoluminescent dosimeters (TLDs). The monitoring network has been established and the
locations were strategically chosen to ensure a monitoring envelope for each radiation source.
During the AWR Project, major sources of direct radiation at the FEMP will undergo change.
For example, the operation of the Radon Control System (RCS) is expected to result in lower
direct radiation levels on top of the silos and elevated direct radiation levels adjacent to the
carbon beds. The removal of the berm surrounding Silos 1 and 2 will result in changes to
existing radiation shielding. These processes, together with the removal and relocation of the
silo wastes to the Transfer Tank Area (TTA) may require modification of the IEMP TLD network
to ensure adequate coverage of direct radiation sources.
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