National Institute for Occupational Safety and Health

Evaluation of INL Burial Ground/RWMC 

Post-1970 (SEC00219)

Timothy Taulbee

Mitch Findley

INL/ANL-W Work Group Teleconference Meeting | March 25, 2019
Overview

 Background

 Changesin Mission

 Waste Retrieval Projects

 Bioassay Monitoring

 Conclusion 

2
Burial Ground Evaluation (March 2017)

 Will continue to evaluate Burial Ground exposures 

outside current SEC00219 evaluation period (post 1970) 

 Why?

 Large scale drum retrieval operations in the later 1970s 

through present 

 If needed we will pursue expanding the class under the 

83.14 process.

3
Burial Ground Evaluation (1977)

Photos from INL Update Presentation to ABRWH on March 22, 2017 4
Radioactive Waste Management Complex

 New facility name in 1970s due to multiple 

operations

 RWMC composed of: 

1. Subsurface Disposal Area 

(old Burial Ground): buried waste

2. Transuranic Storage Area (TSA): 

“above” ground waste

3. Administration and operations area

 RWMC gets its own dosimetry designation 

(Area 815) in 4Q 1975

SRDB 172427, page 54

5

TSA Pad in 1973
Burial Ground in 1970 (end of SEC00219 evaluation period)

SRDB 151677, page 6

6
RWMC Buildings in 1976

SRDB 172427, page 102

7

Early Waste Retrieval (EWR)

Initial Drum Retrieval (IDR)

Transuranic Storage Area (TSA)
RWMC 1995

SRDB 172428, page 15

8
RWMC Today

Over 50 Buildings

Source: Google Images

SRDB 167963, page 29

9
Waste Retrieval Projects

From 1970 through 1978 INL conducted three waste retrieval 

investigations within the Burial Ground/RWMC:

1. Solid Waste Retrieval Test (1971)

2. Initial Drum Retrieval (1974-1978)

3. Early Waste Retrieval (1976-1978)

Production scale retrieval programs: Long-term stored waste retrieval 

project (waste on TSA pads) and buried waste retrieval projects (still 

active today) initiated after the above waste retrieval projects.

10
I. Solid Waste Retrieval Test

In 1971, the AEC requested a series of solid waste retrieval tests on Rocky 

Flats waste buried in the SDA to gain insight into problems that may arise 

from a large-scale retrieval operation. 

First phase: AEC requested retrieval of three specific drums that were 

suspected of containing excessive amounts of plutonium. 

 One of the three specific drums was located. 

 Several hundred drums moved looking for the specific drums. 

 Collected soil samples to determine soil contamination concentrations. 

Most samples were < 10 pCi/g however some were as high as 6 nCi/g. 

(SRDB# 150785, pg 41, 54)

11
Solid Waste Retrieval Test In-Ground Drums (1971)

12 SRDB 172427, page 42
I. Solid Waste Retrieval Test (cont.)

Second phase: Retrieval of multiple waste drums (16) for transport to the 

ARA-I Hot Cell for detailed sorting and sampling studies. All retrievals 

were focused on removing drums from: 

Pit 2 (12 year old stacked waste)

Pit 5 (7 year old dumped waste)

Pits 10 & 11 (18 month old stacked 

waste).

Collected soil samples to determine 

soil contamination concentrations. 

SRDB 150785, page 49

13
Solid Waste Retrieval Test Bagged Drums (1971)

SRDB 172427, page 52 14
Solid Waste Retrieval Test Monitoring

 Anti-C clothing (coveralls, shoe covers, and cotton gloves).

 Air samplers were utilized continuously with one sampler placed upwind 

and one downwind. The filters were changed daily and analyzed for gross 

alpha. 

– Only one excavation site (Pit 5) had airborne concentration of 

“detectable significance.” (SRDB# 150785, pg 51)

• 6.75 x 10-12 uCi Pu/cc (3.375 DAC) over the 3.75 hours worked

• Respirators worn by workers and “whole body counts of principal workers 

at the site showed no detectable Pu uptake.”

– Only site where detectable contamination was found on shoe covers 

(500cpm).

15
Solid Waste Retrieval Test Monitoring

 Health Physics noted in the summary report the following:

– Eberline instruments (PAC-1S) were inadequate to measure contamination 

in the field. Smears counted in a scintillation crystal detector were required 

for detection of most of the contamination encountered. Half-face 

respirators were satisfactory in preventing worker inhalation of Pu. Wholebody counting using special detectors for Pu showed no detectable Pu 

intake for the main workers. (SRDB# 150785, pg 59)

 Drums to ARA-I Hot Cell: highest smear outside drum was 100 cpm. 

 Concluded that best approach was to use dedicated teams. 

16
II. Initial Drum Retrieval Project

 IDR was designed and implemented to 

demonstrate safe retrieval, packaging, 

and transfer to interim storage of drums 

containing TRU waste buried from 1968 

to 1970. All drums from Pits 11 and 12.

 83-gal over-pack drums then changed to 

over-pack cargo containers that held 72 

drums. This change reduced costs and 

improved productivity.

 20,262 drums exhumed/retrieved SRDB 172427, page 104

Cargo containers (white) on TSA Pad

17
Inside ASWS During IDR (1976)

18 SRDB 172427, page 125
Health Physics Monitoring on IDR (1976)

SRDB 172427, page 97

19

SRDB 172427, page 121 (enlarged)
Initial Drum Retrieval Monitoring

 ASWS erected over all retrieval areas

 Anti-C clothing (coveralls, shoe covers, and 

gloves). Carried half-faced respirators. 

 Instrumentation included alpha and 

beta/gamma portable survey instruments, a 

portable gas-proportional counter, 

Stabilized Assay Meter (SAM-II), CAMs, and 

area radiation monitors. 

 All workers included in initial RWMC 

bioassay measurements.

20 SRDB 83907, page 22
III. Early Waste Retrieval Project

 Investigate problems associated with large scale removal of TRU waste 

from primarily Pits 1 and 2. Develop methods and equipment for safe 

retrieval of TRU waste, develop repackaging methods, and determine 

risks and hazards for long-term waste exhumation projects. 

 Pit 2 was chosen because it was open during the 1962 flood and was 

expected to reflect the worst possible conditions for retrieval. 306 drums 

retrieved with 205 (67%) being severely breached.

 “Although alpha-contamination levels greater than 2x106 cpm were 

frequently encountered, available equipment and established safety and 

operating procedures were effective in protecting personnel and the 

environment.” (SRDB 144000, page iii)

21
EWR Layout

 Air Support Weather Shield

(ASWS): inflated fabric building

 Operating Area Confinement

(OAC): modular metal building

within which actual waste

retrieval was performed

“three cell change booth system”

 10 CAMs operated continuously

• 6 inside OAC, 2 inside ASWS, 2 HEPA

22 SRDB 159596, page 16
Early Waste Retrieval Project (1977)

SRDB 172427, page 132

23
Backhoe Operation Inside OAC (1977)

SRDB 172427, page 76 24
Early Waste Retrieval Operation Inside OAC (1977)

SRDB 172427, page 135 25
Example of Waste Encountered on EWR Project (1977)

26 SRDB 172427, page 107
Movement of Operating Area Containment Building (1977)

SRDB 172427, page 88 27
EWR OAC Contamination Surveys

 The Operating Area Confinement (OAC) building was surveyed as 

conditions warranted and also when it was moved.

SRDB 172320

 Per personnel interviews it would take weeks to move the OAC to a new 

excavation area due to the time required to perform adequate 

contamination surveys on the building and equipment:

28
Conducted 12 Worker Interviews

29

 2 Heavy Equipment Operators (HEO)

 1 Laborer

 2 Health Physics Technicians

 1 Health Physicist

 3 Engineers

 2 Managers

 1 Scientist
Summary Of Interviews

 Consistent responses on questions on waste retrieval projects

 Small dedicated workforce

 Work performed with focus on safety

 PPE use and radiological monitoring modified based on anticipated 

hazards

 Continuous Health Physics coverage for any work activities at RWMC

 High reliance and confidence in Health Physics staff

 RWMC was actually a preferred facility to work 

30
RWMC Bioassay Program Implementation

 1977: “First round bioassay screening program” which lead to a 

second round eventually leading to a routine program.

• Initial 16 of 59 analyses (9 workers) statistically positive at 3σ. INL concluded 

the results “do not indicate any cause for alarm or need for further 

modification of the program. There are insufficient data to make meaningful 

assessments of dose or a judgement of the effectiveness of contamination 

controls.”

 1978: 3 month “data gathering program” recommended based on 

initial low-level positive results. Sample all 18 RWMC workers: The 

12 EWR/IDR workers were the top priority. 

SRDB 160667, page 8-9

31
Bioassay Data for 18 RWMC Workers

 Results of “first round bioassay screening” (9 workers)(SRDB 160667, page 8)

• Highest urine result: 0.24 ± 0.06 dpm/sample (Am-241)

• Highest fecal result: 6.22 ± 0.44 dpm/sample (Am-241)

 Fecal bioassay as high as 30 dpm (Pu239/240) from April 1978

(SRDB 160933, page 2)

32

Pu-238 Pu-239 Am-241

Urine Feces Urine Feces Urine Feces Total

# Analysis 8 11 8 12 8 12 59

#>DL 1 3 0 5 1 6 16
Assumptions for Calculation of Intakes

 Highest activities detected via in-vitro bioassay was Am-241.

 Intakes calculated using Am-241 as indicator radionuclide with an 8:1 α

Pu:Am-241 ratio per Table 5 of ORAUT-TKBS-0006-5 (actual ratio 7.62)

 Ratio of Pu-239/240 to Am-241 in highest activity fecal sample for largest 

intake was 7:1 which substantiates ratio assumption

 Assume chronic inhalation of Type S, 5 μm AMAD material from 1/1/1971 

to 12/31/1980

 Five intakes calculated but the top two were clearly larger than the rest. 

Both were HPs during the drum retrieval projects. 

– Highest urine result: 0.24 ± 0.06 dpm/sample (Am-241)

33
Top Five Internal Doses

 Internal Doses for Type S 10-year 

old Weapons Grade Plutonium 

(WGPu) material vs. Type S 20-

year old WGPu provided for 

comparison purposes

 Less than 100 mrem Total 

Effective Dose for all workers 

except top two. 

Worker #1 10 yr WGPu (mrem) 20 yr WGPu (mrem)

1971-1980 Total Eff Dose 303 202

Equivalent Dose – Bone Surface 3414 2294

Equivalent Dose – Lung 1697 1138

Worker #2 10 yr WGPu (mrem) 20 yr WGPu (mrem)

1971-1980 Total Eff Dose 246 164

Equivalent Dose – Bone Surface 2776 1856

Equivalent Dose – Lung 1378 923

Worker #3 10 yr WGPu (mrem) 20 yr WGPu (mrem)

1971-1980 Total Eff Dose 32 22

Equivalent Dose – Bone Surface 360 242

Equivalent Dose – Lung 180 120

Worker #4 10 yr WGPu (mrem) 20 yr WGPu (mrem)

1971-1980 Total Eff Dose 28 19

Equivalent Dose – Bone Surface 313 210

Equivalent Dose – Lung 155 104

Worker #5 10 yr WGPu (mrem) 20 yr WGPu (mrem)

1971-1980 Total Eff Dose 24 16

Equivalent Dose – Bone Surface 272 183

Equivalent Dose - Lung 135 91

34
Summary

 Solid Waste Retrieval Tests (SWRT)

• No bioassay but air monitoring indicating a few DAC in one area

• Project conducted during current SEC class

All externally monitored workers (1970-1974)

 Initial Drum Retrieval (IDR) and Early Waste Retrieval (EWR)

• Small dedicated workforce 

• Bioassay monitoring of workforce for (Pu, Am)

• Low internal doses 

35
Conclusion of RWMC 83.14 Determination Evaluation

 NIOSH does NOT plan to pursue an 83.14 evaluation for the 

Burial Ground/RWMC post-1970. This conclusion was drawn 

after exhaustive document review, bioassay data review, 

personnel interviews, and a review of photographic images 

which clearly demonstrate that the waste retrieval projects 

were performed with a heightened sense of awareness of 

internal exposure potential due to the nature of the work.

 With bioassay data available, we believe internal dose 

reconstruction is feasible. 

36