Page 1 of 26

DOE Review Release 05/22/2017

Evaluation of Method for Assessment of 

Thorium-232 Exposures at the Savannah 

River Site from 1972 to 1989

ORAUT-RPRT-0070 Rev. 00

Effective Date: 05/15/2017

Supersedes: None

Subject Expert(s): James M. Mahathy, Mutty M. Sharfi

Document Owner 

Approval: Signature on File

James M. Mahathy, Document Owner

Approval Date: 05/09/2017

Concurrence: Signature on File

Daniel H. Stempfley, Objective 4 Representative

Concurrence Date: 05/09/2017

Concurrence: Vickie S. Short Signature on File for

Kate Kimpan, Project Director

Concurrence Date: 05/09/2017

Approval: Signature on File

James W. Neton, Associate Director for Science

Approval Date: 05/15/2017

FOR DOCUMENTS MARKED AS A TOTAL REWRITE, REVISION, OR PAGE CHANGE, REPLACE THE PRIOR 

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.

New Total Rewrite Revision Page Change
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 2 of 26

 

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

05/15/2017 00 New document initiated to evaluate the method for assessment of 

doses from 232Th at the Savannah River Site from 1972 through 

1989. Incorporates formal internal and NIOSH review comments. 

Training required: As determined by the Objective Manager. 

Initiated by James M. Mahathy.
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 3 of 26

TABLE OF CONTENTS

SECTION TITLE PAGE

Acronyms and Abbreviations ............................................................................................................... 4

1.0 Purpose ................................................................................................................................... 5

2.0 Work with Thorium ................................................................................................................... 5

3.0 Analysis of Inventory Data To Bound Thorium Doses .............................................................. 7

3.1 NUREG-1400 Approach ............................................................................................... 7

3.2 Area Air Monitoring Data .............................................................................................. 9

4.0 Conclusion ............................................................................................................................. 11

References ........................................................................................................................................ 14

ATTACHMENT A EXAMPLE AIR SAMPLE REPORTS............................................................... 17

LIST OF TABLES

TABLE TITLE PAGE

2-1 232Th inventory, Building 773-A ................................................................................................ 7

3-1 Values of release fraction R ..................................................................................................... 8

3-2 Values of confinement factor C ................................................................................................ 8

3-3 Values of dispersibility factor D ................................................................................................ 8

3-4 Average airborne concentrations, surface contamination levels, and intake rate 

estimates using NUREG-1400 ................................................................................................. 9

4-1 Comparison of the 50-year organ dose associated with the various approaches for 

1-year chronic intake of 232Th ................................................................................................. 12

LIST OF FIGURES

FIGURE TITLE PAGE

3-1 Fraction of sample results expected over censoring level....................................................... 10

3-2 Percent of airborne concentration levels above the censoring level ....................................... 11

4-1 Comparison of various approaches to determine 232Th intake rate......................................... 12

A-1 Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A .................................................. 18

A-2 Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A (continued) ............................... 19

A-3 Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A (continued) ............................... 20

A-4 Air sample locations for E Section.......................................................................................... 21

A-5 Air sample locations for F Section.......................................................................................... 22

A-6 Air sample locations for F Section (continued) ....................................................................... 23

A-7 Air sample locations for E and F Section duct samples .......................................................... 24

A-8 Air sample locations for 773-A stacks..................................................................................... 25

A-9 Example of routine air sample results log sheet ..................................................................... 26
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 4 of 26

 

ACRONYMS AND ABBREVIATIONS 

d day

DAC derived air concentration

DDCP dibutyl N,N-diethylcarbamylphosphonate

DOE U.S. Department of Energy

dpm disintegrations per minute

g gram

hr hour

kg kilogram

mCi millicurie

mrem millirem

NIOSH National Institute for Occupational Safety and Health

ORAU Oak Ridge Associated Universities

pCi picocurie

PEF Plutonium Experimental Facility

PuFF 238PuO2 Fuel Form Facility

SC&A S. Cohen & Associates 

SRDB Ref ID Site Research Database Reference Identification (number)

SRS Savannah River Site

TIOA triisooctlyamine

TFCT Thorium Fuel Cycle Technology Program

THOREX thorium extraction

yr year

μCi microcurie
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 5 of 26

 

1.0 PURPOSE

In Addendum 3 to Savannah River Site (SEC-00103) Special Exposure Cohort Evaluation Report, 

NIOSH proposed methods to reconstruct potential internal doses from exposure to 232Th (NIOSH 

2012) at the Savannah River Site (SRS). These methods are summarized:

• Intakes based on coworker trivalent radionuclide urinalysis results will be used to bound doses 

for the period from 1973 through 1994 providing chronic intake rates of 0.599 pCi/d for type M 

material and 8.06 pCi/d for type S material.

• Intakes based on coworker chest count data will be used to bound doses for the period from 

1995 through 2007 providing chronic intake rates of 22.67 pCi/d for type M and 3.18 pCi/d for 

type S material. 

Since the publication of NIOSH (2012), NIOSH learned that the method used to analyze urine 

samples for trivalent radionuclides was changed in 1990 to alpha spectroscopy, which rendered the 

use of trivalent radionuclide bioassay coworker data impracticable. 

After publication of NIOSH 2012, Sanford Cohen and Associates (SC&A) published the draft white 

paper SC&A Review of Addendum 3 to the NIOSH Savannah River Site Special Exposure Cohort 

(SEC-103) Evaluation Report (SC&A 2013). SC&A questioned: 

1. The use of trivalent radionuclide bioassay coworker data as a surrogate for thorium

2. The use of chest count data to bound intakes of thorium. 

The National Institute for Occupational Safety and Health (NIOSH) responded to those questions in 

the Advisory Board SRS Work Group meeting held on February 5, 2014. NIOSH has proposed 

extending the use of chest count data back to 1990, as discussed in the NIOSH response (NIOSH 

2014) to SC&A issue 27. NIOSH also recently published a new coworker study for thorium based on 

urinalysis results that that were obtained using the triisooctlyamine (TIOA) followed by dibutyl N,Ndiethylcarbamylphosphonate (DDCP) technique. This approach is provided in ORAUT-OTIB-0081 

(ORAUT 2016). The results of the study are that intakes for type S thorium total alpha was 

determined to be 67.59 dpm/d at the 50th percentile and 626.2 dpm/d at the 95th percentile. 

Assuming natural thorium, these represent 232Th intake rates of 33.8 and 313.1 dpm/d, respectively. 

These coworker intakes are applicable from October 1972 through May 1980. There is no indication 

that there was any major work with thorium between in the May 1980 through 1989 time period

(Steimke 1980). 

This document discusses a new method for bounding potential internal doses from thorium for the

period from 1981 to 1989 using known inventories and routine air monitoring data. 

2.0 WORK WITH THORIUM

NIOSH discussed work at SRS using thorium in NIOSH (2012). Through information from interviews 

of former scientists (ORAUT 2013a, 2013b) at SRS, NIOSH has updated the history of the use of 

thorium.

The Alpha Materials Laboratory (in Building 773-A) was placed in operation in 1973; ThO2 was used 

as a surrogate for testing in gloveboxes with the 238Pu fuel form program (DuPont 1972). In 1973, 

gram-quantity ThO2 was again used as a surrogate for plutonium shards in 773-A hot cells to test 

chemical vapor deposition of molybdenum (DuPont 1973). The Team has found no documentation of 

significant production and research activities involving thorium for 1974, 1975, and 1976, although 
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 6 of 26

 

nominal uses of thorium as a surrogate were possible. In 1977, thorium (oxalate powder prepared in 

Building 773-A) was used as a surrogate for plutonium in testing of HB-Line exchange columns 

(DuPont 1978a).

In 1977, SRS began work in Building 773-A as part of the Thorium Fuel Cycle Technology (TFCT)

Program to develop processing technology for spent thorium fuel. The scope of the program included 

broad evaluations to “identify viable thorium/uranium recycle strategies; research and development 

programs to confirm the feasibility of the selected fuel cycle or cycles; a design integration study to 

identify development areas and safeguards and proliferation aspects; and the development and 

testing of key systems, equipment, and components” (DuPont 1984a ). By 1978, nine cells in the 

high-level caves of Building 773-A were prepared for the Alternate Fuel Cycle Technology Program of 

which TFCT was a part (DuPont 1984b). SRS received 4.5 kg (0.45 mCi) of unirradiated ThO2

reflector pellets and used them to test the effects of heat treatment on physical characteristics and 

dissolution (DOE 1978a; ORAUT 2013a, 2013b). This work, in the high-level caves, involved 

mechanical grinding of ThO2. Testing of a conceptual thorium extraction (THOREX) process was 

evaluated using some of that same ThO2 inventory (DOE 1978a). Testing of the conceptual THOREX 

flowsheets continued at SRS using irradiated thorium and uranium from spent fuels stored at the 

Receiving Basin for Offsite Fuel. SRS staff cut sections of irradiated Elk River O2/UO2 fuel rods to test 

off-gas removal characteristics (DOE 1978b).

To test the Plutonium Experimental Facility (PEF, Building 235-F) where 238Pu heat source 

development was to occur, SRS staff put about 300 g of ThO2 into the process line in March 1978 to 

functionally test the facility. The cited reference stated that no health physics problems were 

encountered (DuPont 1978b). By April 1978, all PEF equipment except for the hot press had been 

tested using ThO2 as a surrogate in gloveboxes (DOE 1978b).

In 1979, SRS and Hanford were planning and preparing a small number of 80% ThO2-20% UO2 rod 

assemblies for irradiation in fiscal year 1980 and subsequent postirradiation characterization (DuPont 

1984a). While 30 fuel rods (of varying thorium and uranium mixtures) were prepared at Hanford in 

1979 and shipped to SRS, the irradiation was canceled in May 1980 (Steimke, J. L., 1980). 

Laboratory analyses were performed to evaluate alternative chemical reagents in the dissolution of 

ThO2 (DOE 1978c; ORAUT 2013b). At CMX (a code designation for a facility), SRS performed longterm flow testing for 6 months using one of the Hanford 100% ThO2 fuel rods (DOE 1978c; ORAUT 

2013b). Thirty rods were prepared by Hanford for SRS flow experiments; 12 of the rods were 100% 

ThO2, and the remainder was a mixture of uranium and thorium. Nine of 12 100% ThO2 rods were 

used for the long-term flow tests. All 30 rods were stored in a cage in Building 773-A, Room C 070 

(Steimke 1980). Work with the Hanford thorium material was canceled in May 1980 (Steimke 1980; 

DuPont 1984a).

SRS investigated tritium removal and retention processes for ThO2 fuels including the associated 

evaluation of other volatile radioisotopes. Four types of mechanically blended ThO2-UO2 unirradiated 

fuel pellets were received from General Electric of Canada for use in ThO2 experiments (DOE 1978d). 

Two additional types of ThO2-UO2 unirradiated fuel pellets were received from General Electric of 

Canada (DOE 1978e). Work at SRS on these types of analyses continued through December 1978 

(DOE 1978e).

In November 1980, SRS began stocking thorium nitrate crystals in the 773-A “Chem Stores” for use in 

research and as surrogate material with an inventory of 3.4 kg (0.34 mCi) (Author unknown 2012). 

The quantity in the material accountability ledgers had decreased to 2.9 kg (0.29 mCi) in March 1982, 

to 2.7 kg (0.27 mCi) in May 1982, and to 1.2 kg (0.12 mCi) in August 1984. A notation denoted the 

latter entry as “inventory write-off.” The inventory was further decreased to 1.0 kg (0.1 mCi) in 

February 1986 and remained at that amount until February 1991, after which there were no further 

entries for thorium for 773-A Chem Stores (Author unknown 2012). SRS continued to use thorium in 
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 7 of 26

 

laboratory analyses in 1981 as a direct reagent and as a surrogate for other radionuclides (DuPont 

1987a, pp. 179, 183; Monson and Hall 1981).

The thorium inventory in 773-A steadily declined from 1981 when the TFCT Program ended through 

1987; most of the thorium was sent to the burial grounds. Less than 5 kg (0.5 mCi) thorium remained 

in 773-A during 1987. In 1988, SRS began acquiring 232Th for use in research of waste glass for the 

defense waste program. This research, using gram quantities, was likely performed in 1988 and 1989 

in laboratory-scale studies. Table 2-1 lists the 232Th inventory of Building 773-A by year from 1973 to 

1989. 

Table 2-1. 232Th inventory, Building 773-A. 

Year Operation

Inventory

(kg)

1973 Storage, surrogate 154.0

1974 Storage, surrogate 104.0

1975 Storage, surrogate 104.0

1976 Dissolution studies, storage, surrogate 89.4

1977 Alternative fuels program, dissolution studies, storage, surrogate 85.4

1978 Alternative fuels program, dissolution studies, storage, surrogate 56.6

1979 Alternative fuels program, tritium studies, storage, surrogate 83.4

1980 Alternative fuels program, tritium studies, storage, surrogate 108.6

1981 Storage 110.9

1982 Storage 85.5

1983 Storage 32.5

1984 Storage 21.6

1985 Storage 17.9

1986 Storage 5.4

1987 Storage 4.9

1988 Storage, surrogate 17.0

1989 Storage, surrogate 41.7

3.0 ANALYSIS OF INVENTORY DATA TO BOUND THORIUM DOSES

3.1 NUREG-1400 APPROACH

NUREG-1400, Air Sampling in the Workplace (NRC 1993), provides an approach to evaluate the 

need for air sampling during work based on the amount of radioactive material included in the work 

process. The approach is influenced by the type of material, the release potential, and the 

confinement of the material. Equation 3-1 describes this relationship: 

6 I Q RCD p 10− = × ××× (3-1)

where

Ip = estimated intake.

Q = estimated quantity of unencapsulated radioactive material available for inhalation 

by a worker in a room or location. The estimate of the quantity of handled 

material was determined based on the change in inventory in any given month. If 

no change of inventory occurred, then it was assumed no work for that period of 

time was performed.

1 × 10-6 = a combination of the fraction of material that is released to the environment times 

the fraction of that material that is inhaled.
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 8 of 26

R = release fraction, based on the physical form of the material (Table 3-1). A 

release fraction value of 0.01, associated with nonvolatile powders, was 

assumed.

C = confinement factor, which takes into consideration the engineering controls in 

place (Table 3-2). During the period of interest it is reasonable to assume that 

any process associated with radioactive material would have routinely occurred in 

a fume hood or under some form of capture ventilation. Therefore a confinement 

factor value of 0.1 was assumed.

D = dispersibility factor, which takes into consideration energy that is added by the 

work process. This could be from heating, grinding, milling, boiling, or adding 

chemicals that cause an exothermic chemical reaction to occur (Table 3-3). It is 

assumed that the handling of this material would have inherently added chemical 

or mechanical energy. Therefore, a dispersibility factor value of 10 was

assumed.

Table 3-1. Values of release fraction R (NRC 1993).

Physical form

Release fraction

R

Gases or volatile material 1.0

Nonvolatile powders 0.01

Solids, (e.g., uranium fuel pellets, cobalt or iridium 

metal)

0.001

Liquids 0.01

Encapsulated material 0

Table 3-2. Values of confinement factor C (NRC 1993).

Work location

Confinement factor

C

Material handled in a glovebox 0.01

Material handled in a well-ventilated hood 0.1

Material handled in an open work area 1

Table 3-3. Values of dispersibility factor D (NRC 1993).

Added energy

Dispersibility factor

D

Cutting, grinding, heating, or chemical reactions 10

None 1

Based on the assumptions above, the NUREG-1400 approach (NRC 1993) was used to calculate a 

potential monthly intake based on the change of inventory between months (which represents the 

amount of processed material). Assuming all of the inventory was associated natural thorium. 

Therefore, 232Th would only represent 50% of the calculated activity. The estimated monthly intakes 

were converted to daily intake rates and averaged over the entire inventory data period (Table 3-4). 

Based on these estimated daily intake rates, an associated average air concentration was calculated. 

The expected surface contamination levels were calculated by determining that amount of activity that 

would build up due to the settling of the airborne particulate based on guidance in Battelle-TBD-6000, 

Technical Basis Document: Site Profiles for Atomic Weapons Employers That Worked Uranium 

Metals (NIOSH 2011).
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 9 of 26

Table 3-4. Average airborne concentrations, surface contamination levels, and intake rate estimates 

using NUREG-1400.

Location

Average thorium surface 

contamination estimates

(dpm/100 cm2)

Average thorium airborne 

concentrations

(μCi/cm3)

Th-232 inhalation intake rate

(dpm/calendar day)

Building 773-A 2.1 0.05 ×10-12

(2.4% DAC or 0.1 dpm/m3) 0.45

Stores 0.2 0.005 ×10-12

(0.2% DAC or 0.01 dpm/m3) 0.05

3.2 AREA AIR MONITORING DATA

During the 1970s and 1980s, SRS had a routine air monitoring program. These samples were 

generally collected daily and counted for gross alpha and beta activity. The calculated air 

concentrations from these air samples were only reported in the air sample data sheets if the air 

sample concentration was above 1 × 10-12 μCi alpha/cm3 (2.22 dpm/m3

), or 50% of the plutonium 

derived air concentration (DAC). Figure A-9 is an example air sample datasheet. These sheets also 

indicate when respiratory protect were worn in conjunction with the collection of the air sample.

Much of the air monitoring data collected for 773-A was censored (reported) at less than 

1 × 10-

12 μCi alpha/cm3

. The Team analyzed available air sample data to determine if there was a 

systematic nature to routine air concentrations that exceeded the censoring level. Due to the large 

number of air samples SRS collected between 1972 and 1989, it was determined that a random 

number of samples would be analyzed to estimate the true population percentage of air samples that 

exceeded the censoring level. The analysis used a sample of results selected from 1975, 1981, 1984, 

and 1987 to determine if a more detail analysis was needed. For each year, a random list of 

workdays (weekends and holidays were excluded) were created to provide a means to collect a 

random sample from the large set of available data. Air sample results were recorded, based on the 

random list of workdays, until a minimum number of air samples results were compiled.

The Team used a set of gross alpha air monitoring obtained from 1974 through 1977 at the 238PuO2

Fuel Form Facility (PuFF) data (ORAUT 2017). The PuFF data was sampled and analyzed for the 

effect of the number of samples versus the variability in ability to determine the number of samples 

over a set limit. For each of the years 1974 through 1977, 10,000 PuFF air concentration results were 

simulated in groups of random 20 days. The sampling was continued in increments of 5 days up to 

80 days. 

Summary statistics for 1974, 1975, 1976, and 1977 were plotted for each 5-day sample and are 

provided in Figure 3-1. The dot at 20 days, and subsequent samples, represent the median of the 

fraction of results over the censoring level for the 10,000 samples (y-axis). The error bars are the 

uncertainty in that fraction (95% confidence interval). The black horizontal line represents the actual 

median for all of the PuFF data in year. The PuFF data does not contain exactly the same number of 

rooms sampled each day such that the 10,000 simulations of the number of days drew a variety of 

actual number of results. The numbers on the top x-axis are the median number of results pulled for 

the 10,000 simulations of 20 days. As the numbers of days and results increase, the uncertainty in 

the median narrows and the sampled median approaches the population median. The number of 

random results to pull per year from 773-A air concentration data was determined by visually 

identifying the point on all of the plots, using the top x-axis (number of results), at which there is little 

change in the sample median. Using this analysis, the Team selected a sample size of 750 randomly 

selected air concentrations to provide acceptable confidence in the determination that the limit was 

considered bounding.
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 10 of 26

 

Figure 3-1. Fraction of sample results expected over censoring level. Censoring level for this dataset 

was 0.1 DAC.

Based on the determinations above, 750 air sample results for each year sampled were compiled and 

analyzed to determine the percent of the sample group (and its approximate 95% confidence interval) 

that exceeded the censoring level (50% DAC). Only air concentrations associated with the 773-A 

laboratories were considered. Each result was categorized as either less than the bounding value or 

not. All of the reported results were converted to the percentage of total results that are not bounded 

by censoring level. The intervals were computed using a bootstrapping technique. Figure 3-2 

summarizes the results. 
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 11 of 26

 

Figure 3-2. Percent of airborne concentration levels above the censoring level. (DuPont 1975a to 

1975e, 1981a to 1981f, 1984c to 1984g, 1987b to 1987d). 

High, 3.73%

Median, 2.52%

Low, 1.47%

High, 4.40%

Median, 3.06%

Low, 1.87%

High, 2.67%

Median, 1.73%

Low, 0.80%

High, 4.67%

Median, 3.30%

Low, 2.13%

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

1974 1976 1978 1980 1982 1984 1986 1988

Year

Percent above the censoring level.

Based on the statistical confidence intervals themselves and the consistency between them, there is

no indication that additional sampling is necessary in order to draw a conclusion from this data. With 

indications that more than 95% of the air samples SRS collected in thorium work areas were below 

the censoring level of 1 × 10-12 μCi alpha/cm3 (2.22 dpm/m3

), the censoring level is considered to be a 

bounding estimate of the potential airborne concentration to which a worker might have been 

exposed. 

The daily inhalation intake rate associated with an air concentration of 1 × 10-12 μCi alpha/cm3 was 

calculated (assuming a breathing rate of 1.2 m3

/hr for 8 hr/workday and 250 workdays/yr) to be 

14.6 dpm alpha/calendar day (assuming natural thorium, this results in a 232Th inhalation intake rate of 

4.87 dpm/d). Based on guidance in OCAS-TIB-009, Estimation of Ingestion Intakes (NIOSH 2004), 

this air concentration would also be associated with an ingestion intake rate of 0.30 dpm alpha per 

calendar day (assuming natural thorium, this results in a 232Th ingestion intake rate of 0.1 dpm/d). 

4.0 CONCLUSION

Based on a source term analysis, NUREG-1400, the average air concentration that a worker could 

have been exposed to would likely not exceed 1 × 10-13 μCi/cm3

. However, available air concentration 

data was censored at a level that could not validate this low level of exposure. In addition, the 

analysis of the urinalysis data extracted via the TIOA-DDCP technique could not validate this low level 

of exposure. Figure 4-1 is a comparison of the intake rates using the three different approaches.
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 12 of 26

 

Figure 4-1. Comparison of various approaches to determine 232Th intake rate. 

0

5

10

15

20

25

30

35

1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989

NUREG-1400 Air Monitoring 50% Co-Worker (1973-1980) 50% Co-Worker (1981-1989)

Year

Thorium-232 Type S Intake Rate (dpm/day)

In addition, a comparison of the 50-year organ dose was made for a chronic 1-year exposure to each 

of four target organs (lung, bone surface, colon, and prostate). This comparison is provided in 

Table 4-1.

Table 4-1. Comparison of the 50-year organ dose associated with the various approaches 

for 1-year chronic intake of 232Th. 

Organ NUREG-1400 Air monitoring 50% coworker dose Units

Lung 0.021 0.228 1.583 rem

Bone Surface 0.038 0.415 2.879 rem

Colon <0.001 0.001 0.009 rem

Prostate <0.001 0.001 0.008 rem

The NUREG-1400 approach likely gives the most realistic exposure estimate for thorium from 1981 to

1989. However, given the limitations of the air data, since it results in an estimated air concentration 

below the reporting level, it is difficult to draw any conclusions on how bounding of an estimate it 

would be. The coworker intakes presented in ORAUT (2016) are considered bounding but result in 

estimated exposures that are not supported by the air data during the same time period. If routine air 
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 13 of 26

 

concentrations were at the levels associated with the coworker intake rates, there should have been a 

systemic air concentration 6 to 7 times the reporting level. There is no indication of a systemic air 

concentration above the reporting level; therefore, after 1980, the intake rate based on the reporting 

level of the air data is considered the best estimate of routine thorium exposure and represents a 

sufficiently accurate bounding scenario. 
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 14 of 26

REFERENCES

Author unknown, 2012, SRS thorium inventory accountability data, 1976 through 1998. [SRDB Ref 

ID: 110849]

DOE (U.S. Department of Energy), 1978a, Monthly Status and Progress Report February 1978, 

Savannah River Operations Office, Aiken, South Carolina, February. [SRDB Ref ID: 104981]

DOE (U.S. Department of Energy), 1978b, Monthly Status and Progress Report April 1978, Savannah 

River Operations Office, Aiken, South Carolina, April. [SRDB Ref ID: 104983]

DOE (U.S. Department of Energy), 1978c, Monthly Status and Progress Report May 1978, Savannah 

River Operations Office, Aiken, South Carolina, May. [SRDB Ref ID: 104984]

DOE (U.S. Department of Energy), 1978d, Monthly Status and Progress Report July 1978, Savannah 

River Operations Office, Aiken, South Carolina, July. [SRDB Ref ID: 104986]

DOE (U.S. Department of Energy), 1978e, Monthly Status and Progress Report September 1978, 

Savannah River Operations Office, Aiken, South Carolina, September. [SRDB Ref ID: 

104989]

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Carolina, October. [SRDB Ref ID: 112082]

DuPont (E. I. du Pont de Nemours and Company), 1973, Savannah River Laboratory Monthly Report 

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Carolina, July. [SRDB Ref ID: 45961]

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results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 159318]

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results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 159806]

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results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 159807]

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results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 159808]

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results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 161020]

DuPont (E. I. du Pont de Nemours and Company), 1978a, Works Technical Department, Report for 

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68279]

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68060] 
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 15 of 26

DuPont (E. I. du Pont de Nemours and Company), 1978d, Savannah River Laboratory Monthly Report 

December 1978, DP-78-1-12, Savannah River Laboratory, Aiken, South Carolina, December. 

[SRDB Ref ID: 104954]

DuPont (E. I. du Pont de Nemours and Company), 1981a, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 159272]

DuPont (E. I. du Pont de Nemours and Company), 1981b, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 159285]

DuPont (E. I. du Pont de Nemours and Company), 1981c, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 159291]

DuPont (E. I. du Pont de Nemours and Company), 1981d, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 161029]

DuPont (E. I. du Pont de Nemours and Company), 1981e, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 161030]

DuPont (E. I. du Pont de Nemours and Company), 1981f, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 161031]

DuPont (E. I. du Pont de Nemours and Company), 1984a, History of the Savannah River Laboratory, 

Volume IV – General, DPST-62-200-IV, Savannah River Laboratory, Aiken, South Carolina, 

August. [SRDB Ref ID: 49497]

DuPont (E. I. du Pont de Nemours and Company), 1984b, History of the Savannah River Laboratory 

Volume III – Power Reactor and Fuel Technology, DPST-62-200-III, Savannah River Plant, 

Aiken, South Carolina, June. [SRDB Ref ID: 90054]

DuPont (E. I. du Pont de Nemours and Company), 1984c, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 108678]

DuPont (E. I. du Pont de Nemours and Company), 1984d, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 108685]

DuPont (E. I. du Pont de Nemours and Company), 1984e, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 108687]

DuPont (E. I. du Pont de Nemours and Company), 1984f, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 108691]

DuPont (E. I. du Pont de Nemours and Company), 1984g, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 108692]

DuPont (E. I. du Pont de Nemours and Company), 1987a, Savannah River Scientific and Technical 

Documents, 1975–1986, DOE/TIC-3407, Savannah River Site, Aiken, South Carolina, August. 

[SRDB Ref ID: 49392]

DuPont (E. I. du Pont de Nemours and Company), 1987b, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 108585]

DuPont (E. I. du Pont de Nemours and Company), 1987c, collection of air sampling information and 

results, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 108592]
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 16 of 26

DuPont (E. I. du Pont de Nemours and Company), 1987d, collection of routine air samples and stack 

calculations, Savannah River Site, Aiken, South Carolina. [SRDB Ref ID: 108651]

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Site (SEC-00103) Special Exposure Cohort Evaluation Report, Division of Compensation 

Analysis and Support, Cincinnati, Ohio, November 20. [SRDB Ref ID: 158744]

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Review of Addendum 3 to the NIOSH Savannah River Site Special Exposure Cohort (SEC00103) Evaluation Report, Division of Compensation Analysis and Support, Cincinnati, Ohio, 

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NUREG-1400, Washington, D.C., September. [SRDB Ref ID: 20129]

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Plutonium Fuel Facility Construction Workers in Building 235-F at the Savannah River Site, 

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ATTACHMENT A 

EXAMPLE AIR SAMPLE REPORTS

LIST OF FIGURES

FIGURE TITLE PAGE

A-1 Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A .................................................. 18

A-2 Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A (continued) ............................... 19

A-3 Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A (continued) ............................... 20

A-4 Air sample locations for E Section.......................................................................................... 21

A-5 Air sample locations for F Section.......................................................................................... 22

A-6 Air sample locations for F Section (continued) ....................................................................... 23

A-7 Air sample locations for E and F Section duct samples .......................................................... 24

A-8 Air sample locations for 773-A stacks..................................................................................... 25

A-9 Example of routine air sample results log sheet ..................................................................... 26
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 18 of 26

ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-1. Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A 

(DuPont 1981e). 
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ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-2. Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A 

(continued) (DuPont 1981e). 
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ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-3. Air sample locations for 773-A, 735-A, 774-A, 776-A, 779-A 

(continued) (DuPont 1981e). 
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ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-4. Air sample locations for E Section (DuPont 1981e). 
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ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-5. Air sample locations for F Section (DuPont 1981e). 
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ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-6. Air sample locations for F Section (continued) (DuPont 1981e). 
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ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-7. Air sample locations for E and F Section duct samples (DuPont 1975d). 
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ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-8. Air sample locations for 773-A stacks (DuPont 1975d). 
Document No. ORAUT-RPRT-0070 Revision No. 00 Effective Date: 05/15/2017 Page 26 of 26

ATTACHMENT A

EXAMPLE AIR SAMPLE REPORTS (continued)

Figure A-9. Example of routine air sample results log sheet (DuPont 1981a).