TO: Advisory Board on Radiation and Worker Health Work Group on TBD-6000 

FROM: Robert Anigstein and John Mauro, SC&A 

SUBJECT: Alternative Calculations of Resuspension at GSI 

DATE: October 22, 2013 

Alternative Calculations of Resuspension at GSI 

1 Background 

As stated in our earlier memo (Anigstein and Mauro 2013), we believe that inhaled activities of 

uranium during the residual period should be based on a resuspension factor (RF) of 10-5m

-1, 

rather than the RF of 10-6 m-1 used by NIOSH. In the course of a discussion of this issue during 

the October 11, 2013, teleconference meeting of the Work Group on TBD-6000, one of us (RA) 

cited two alternative methods of calculating airborne uranium dust concentration at the time of 

the 1993 FUSRAP cleanup of the Old Betatron Building that produced comparable results. The 

work group asked SC&A to document its findings. 

2 Methodology of Alternative Methods 

Our proposed method starts with the surface contamination of 1.34 × 105

 dpm/m2 during the 

period of AEC operations, as cited by Allen (2013). The FUSRAP cleanup of the Old Betatron 

Building took place in June 1993, at the end of the 27th year of the residual period. According to 

Sharfi (2012), “If no data are available for airborne radioactivity levels during the residual 

period, a source term depletion factor of 0.00067 d-1 . . . can be used in conjunction with the 

available operational period data.” Sharfi (2012, Table 4-2) recommends that the airborne 

activity concentration should be reduced by a factor of 1.73 × 10-3 during the 27th year. 

Applying this factor in the present case, and assuming our proposed RF of 10-5m

-1, yields an 

airborne uranium activity of 1.34 × 105 dpm/m2 × 10-5m

-1 × 1.73 × 10-3 = 2.32 × 10-3 dpm/m3

. 

Our alternative method is based on the results of the survey of the Old Betatron Building 

performed by the Oak Ridge National Laboratory (ORNL), starting on June 7, 1993, as reported 

by Murray and Brown (1994, Table 4). The authors list the α-radiation levels at 31 random 

locations on the first floor of this building. These random samples constitute the best available 

data for estimating the average contamination level on the floor of the shooting room of the Old 

Betatron Building. 

Figure 1 shows the locations of the measurements reported by Murray and Brown (1994), 

superimposed on a map of the first floor of the Old Betatron Building. The blue squares denote 

the random locations. In addition, the ORNL team scanned the entire floor using large-area floor 

monitors and G-M pancake probes. Red squares indicate locations that showed elevated ß/γ

activities. Since they represent biased samples, the activities at these locations were not used in 

the present calculations, but are shown to indicate the localized distribution of these “hot spots.” 

At 13 of the 25 random locations, the α-radiation levels were <MDA. Since Murray and Brown 

state that the MDA = 50 dpm/100 cm2

, we set readings of “<MDA” to one-half that value— 

Alternative Calculations of Resuspension at GSI -1- SC&A –October 22, 2013
 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker
 

Health for factual accuracy or applicability within the requirements of 42 CFR 82.
 
 

 

25 dpm/100 cm2, as shown in Table 1 of the present memo. The average of the 31 readings is 

equal to 26.2 dpm/100 cm2 or 2.62 × 103

 dpm/m2. 

Figure 1. Locations of α-Activity Measurements in Old Betatron Building 

Reviewing some of the resuspension factors cited by Sharfi (2012), we note that a factor of 

10-6 m

-1 is appropriate for a decommissioned facility in which surfaces were cleaned or washed, 

no fresh radioactive material had accumulated, and a facility in was a quiescent state. These 

conditions would apply to the Old Betatron Building at the time of the FUSRAP cleanup. 

Applying this RF to the average surface contamination level on the first floor of the Old Betatron 

Building results in an airborne activity concentration of 2.62 × 10-3 dpm/m3

, which is remarkably 

close to the value of 2.32 × 10-3 dpm/m3 obtained by using the NIOSH approach but with an RF 

of 10-5. 

3 Conclusion 

We observe that the depletion factors cited by Sharfi (2012, Table 4-2) reflect both a decrease in 

the surface contamination level due to removal and a decrease in the RF, a result of the surficial 

contamination becoming less available for resuspension. We thus conclude that the estimated 

airborne activity concentrations in 1993, calculated from the FUSRAP survey measurements and 

an RF of 10-6 m

-1, validate the proposed methodology of using the surficial activity concentration 

calculated by NIOSH for the operational period, coupled with the depletion rate recommended 

by Sharfi (2012) and a constant RF of 10-5m-1. 

Alternative Calculations of Resuspension at GSI -2- SC&A – October 22, 2013
 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker
 

Health for factual accuracy or applicability within the requirements of 42 CFR 82.
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 1. Alpha Activity Concentrations on Floor of Old Betatron Building 

Sample location Alpha (dpm/100 cm2)
 

North East Reported Assumeda
 

0 4 <MDA 25 
 

Average 26.2
 

0 8 <MDA 25 
 

0 14 <MDA 25 
 

1 6 <MDA 25 
 

1 10 <MDA 25
 

1 17 <MDA 25 
 

2 2 <MDA 25 
 

2 4 <MDA 25 
 

2 11 21 21 
 

3 3 <MDA 25 
 

3 7 35 35
 

3 9 <MDA 25 
 

4 12 <MDA 25 
 

4 15 <MDA 25 
 

5 6 <MDA 25 
 

6 7 <MDA 25 
 

6 10 <MDA 25 
 

7 8 <MDA 25 
 

7 13 35 35 
 

7 17 <MDA 25 
 

8 1 <MDA 25 
 

9 5 <MDA 25 
 

9 14 <MDA 25 
 

10 17 42 42
 

11 1 <MDA 25
 

14 5 28 28
 

18 3 <MDA 25
 

20 1 <MDA 25
 

21 3 <MDA 25
 

21 5 <MDA 25
 

22 4 <MDA 25
 

Source: Murray and Brown (1994, Table 4) 

a

 Assuming “<MDA” = 25 dpm/100 cm2 

Alternative Calculations of Resuspension at GSI -3- SC&A – October 22, 2013
 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker
 

Health for factual accuracy or applicability within the requirements of 42 CFR 82.
 
 

 

References 

Allen, D. 2013. “GSI White Paper: Issues Raised in February 21, 2013 Work Group Meeting.” 

http://www.cdc.gov/niosh/ocas/pdfs/dps/dc-gsiwgiss-0413.pdf 

Anigstein, R., and J. Mauro. 2013. “SC&A Response to NIOSH White Paper: ‘Summary Dose 

Estimates for GSI’.” Memo to Advisory Board on Radiation and Worker Health Work Group on 

TBD-6000. http://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/sca-gsisde-100613.pdf 

Murray, M. E., and K. S. Brown. 1994. “Results of the Independent Verification Survey at the 

Old Betatron Building, Granite City, Illinois (GSG001),” ORNL/RASA-94/2. Oak Ridge, TN: 

Oak Ridge National Laboratory. 

Murray, M. E., and M. S. Uziel. 1992. “Results of the Radiological Survey at the New Betatron 

Building, Granite City Steel Facility, Granite City, Illinois (GSG002),” ORNL/RASA-91/8. Oak 

Ridge, TN: Oak Ridge National Laboratory. 

Sharfi, M. M. 2012. “Dose Reconstruction During Residual Radioactivity Periods at Atomic 

Weapons Employer Facilities,” ORAUT-OTIB-0070, Rev. 01. 

http://www.cdc.gov/niosh/ocas/pdfs/tibs/or-t70-r1.pdf. 

Alternative Calculations of Resuspension at GSI -4- SC&A – October 22, 2013
 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker
 

Health for factual accuracy or applicability within the requirements of 42 CFR 82.