Page 1 of 67

DOE Review Release 09/26/2016

An Evaluation of Neptunium Operations at 

Savannah River Site

ORAUT-RPRT-0065 Rev. 00

Effective Date: 09/19/2016

Supersedes: None

Subject Expert(s): James M. Mahathy

Document Owner 

Approval: Signature on File

James M. Mahathy, Document Owner

Approval Date: 09/15/2016

Concurrence: Michael S. Kubiak Signature on File for

Daniel H. Stempfley, Objective 4 Representative

Concurrence Date: 09/15/2016

Concurrence: Vickie S. Short Signature on File for 

Kate Kimpan, Project Director

Concurrence Date: 09/15/2016

Approval: Signature on File

James W. Neton, Associate Director for Science

Approval Date: 09/19/2016

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-0065 Revision No. 00 Effective Date: 09/19/2016 Page 2 of 67

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

09/19/2016 00 New report for methods and models for reconstructing internal 

radiation doses to workers at the Savannah River Site who were 

potentially exposed to 237Np based on site records. Incorporates

formal internal and NIOSH review comments. Training

required: As determined by the Objective Manager. Initiated by

James M. Mahathy and Billy P. Smith.
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 3 of 67

TABLE OF CONTENTS

SECTION TITLE PAGE

Acronyms and Abbreviations ............................................................................................................... 5

1.0 Introduction .............................................................................................................................. 7

2.0 History of Neptunium Recovery................................................................................................ 7

2.1 Recovery from Irradiated Uranium................................................................................ 9

2.2 Recovery from Irradiated Neptunium Targets ............................................................. 10

2.3 Conversion to Neptunium Oxide ................................................................................. 11

3.0 Fabrication of Neptunium Targets .......................................................................................... 13

4.0 Neptunium Operations After 1984.......................................................................................... 18

5.0 Ancillary Work ........................................................................................................................ 19

6.0 Timeline ................................................................................................................................. 22

7.0 Inventory ................................................................................................................................ 22

8.0 Radiation Safety and Monitoring ............................................................................................ 24

8.1 Radiological Controls.................................................................................................. 24

8.2 Workplace controls ..................................................................................................... 27

8.3 Worker Monitoring ...................................................................................................... 31

8.4 Incidents..................................................................................................................... 38

9.0 Conclusion ............................................................................................................................. 41

References ........................................................................................................................................ 43

ATTACHMENT A HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS........................... 60

LIST OF TABLES

TABLE TITLE PAGE

3-1 Plutonium contamination from HB Line .................................................................................. 13

3-2 Alpha ratio..............................................................................................................................13

3-3 Comparison of tubes extruded in Building 321-M................................................................... 17

5-1 Ancillary work.........................................................................................................................21

8-1 Health physics surveys in Building 773-A............................................................................... 30

8-3 Neptunium urinalysis data...................................................................................................... 33

8-4 Number of 237Np samples by area.......................................................................................... 33

8-2 Neptunium intakes .................................................................................................................34

8-5 Special hazard incidents by location ...................................................................................... 39

A-1 Health physics monitoring of specific events .......................................................................... 60

A-2 Special hazards incidents....................................................................................................... 65
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LIST OF FIGURES

FIGURE TITLE PAGE

2-1 Neptunium material flow...........................................................................................................8

2-2 Modified PUREX process for recovery of neptunium source .................................................... 9

2-3 Neptunium recovered from PUREX waste, January 1963 ...................................................... 10

2-4 Process for neptunium recovery from enriched uranium ........................................................ 11

2-5 Process for recovery of neptunium from irradiated targets ..................................................... 12

3-1 Building 235-F layout .............................................................................................................14

3-2 Workers on the neptunium billet line, Building 235-F.............................................................. 14

3-3 Maintenance side of the neptunium billet line, Building 235-F ................................................ 15

3-4 Hot-press-bond furnace for fabrication of neptunium target slugs........................................... 15

3-5 Front entrance of extrusion press, Building 321-M ................................................................. 17

3-6 Front entrance and rear exit of extrusion press, Building 321-M............................................. 18

6-1 Neptunium process flowchart ................................................................................................. 22

6-2 Neptunium process timeline ................................................................................................... 23

7-1 Neptunium by activity by major process ................................................................................. 23

8-1 Neptunium-plutonium frame without ion exchange columns................................................... 25

8-2 Ion exchange column.............................................................................................................26

8-3 Routine air monitoring results, Building 235-F........................................................................ 27

8-4 Special air monitoring results, Building 235-F......................................................................... 28

8-5 Process air monitoring results, Building 235-F ....................................................................... 29

8-6 Daily control sheet, Building 235-F......................................................................................... 29

8-7 Survey of neptunium billets to be shipped to Building 321-M.................................................. 30

8-8 Survey of neptunium billets when received at Building 321-M ................................................ 30

8-9 Survey of freshly extruded neptunium tubes at Building 321-M .............................................. 31

8-10 Survey of neptunium billets when received at Building 321-M ................................................ 31

8-11 Survey of plutonium billets to be shipped to Building 321-M................................................... 32

8-12 Bioassay requirements, Construction Division........................................................................ 32

8-13 Pu:Np mass ratios..................................................................................................................36

8-14 Pu:Np activity ratios ...............................................................................................................36

8-15 Neptunium intake rates .......................................................................................................... 37

8-16 Neptunium excretion rates ..................................................................................................... 37
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 5 of 67

ACRONYMS AND ABBREVIATIONS

AEC U.S. Atomic Energy Commission

Ci curie

CFR Code of Federal Regulations

cm centimeter

CTW construction trade worker

D&D decontamination and decommissioning

DOE U.S. Department of Energy

dpm disintegrations per minute

ft feet

g gram

HAW high-activity waste

HPRED Savannah River Site Health Protection Radiation Exposure Database

hr hour

in. inch

kg kilogram

L liter

M molar

mCi millicurie

mg milligram

min minute

mm millimeter

mo month

mR milliroentgen

mrem millirem

n neutron

NIM nuclear incident monitor

NIOSH National Institute for Occupational Safety and Health

NMMSS Nuclear Materials Management and Safeguards System

NOCTS NIOSH-Division of Compensation Analysis and Support Claims Tracking System

ORAU Oak Ridge Associated Universities

ORNL Oak Ridge National Laboratory

ppm parts per million

PUFF Plutonium Fuel Form Fabrication Facility

PUREX plutonium-uranium extraction

R roentgen

R&D research and development

RCG radioactivity concentration guide
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 6 of 67

SHI Special Hazard Incident

SRDB Ref ID Site Research Database Reference Identification (number)

SRL Savannah River Laboratory

SRS Savannah River Site

WBC whole-body count

wt% weight percent

yr year

γ gamma particle

μCi microcurie

°C degrees Celsius
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 7 of 67

 

1.0 INTRODUCTION

Since reactor start up, 237 Np has been produced at Savannah River Site (SRS) as a byproduct, but it

was not removed from early radioactive waste streams during chemical processing of irradiated fuel

elements. Neptunium-237 was produced when depleted uranium (containing 238 U) or enriched

uranium (containing 235 U) was irradiated in one of the nuclear reactors (Driggers and St. John 1957). 

Neptunium targets were also irradiated for production of 238 Pu. In this report, the Oak Ridge

Associated Universities (ORAU) Team has provided (1) the history of neptunium recovery, fabrication, 

and other uses at SRS along with a detailed timeline; (2) information on the radiological design of

production processes; (3) information on the radiation monitoring of processes and workers; and (4)

methods and models for reconstructing internal radiation doses to workers who were potentially 

exposed to 237 Np.

2.0 HISTORY OF NEPTUNIUM RECOVERY

By 1957, with the beginning of the Space Race between the United States and the Soviet Union,

the U.S. Atomic Energy Commission (AEC) developed a serious interest in using 237 Np to produce

238 Pu. Plutonium-238 was thought to be useful as a heat source for thermoelectric generators for

powering satellites. SRS and other AEC sites began studying how 237 Np could be recovered from

reactor waste flows (Siddall 1957a; Colven 1957). SRS studied the behavior of neptunium in HArea (Siddall 1957b; DuPont 1957a). In 1958, the AEC tasked SRS to produce 238 Pu by irradiating

237 Np, provoking the following reaction:

237 238 238 Np (n,γ) Np Pu → (2-1)

An evaluation of the feasibility of interim separation of 238Pu from irradiated 237 Np resulted in a 

preliminary process outline, a high spot-cost estimate, and a review of the effects on other programs 

(DuPont 1958a). To use neptunium as a target for production of 238 Pu, methods were needed to 

recover neptunium from waste streams of irradiated depleted uranium and irradiated enriched 

uranium, and to separate and purify both neptunium and 238 Pu from irradiated neptunium (Poe, Joyce, 

and Martens 1963; DuPont 1962, 1963a). Tests of the anion exchange method for recovery of 

neptunium from high-activity waste (HAW) concentrate were performed at the TNX facility using 

thorium as a surrogate.

SRS designed a neptunium slug and bean pilot fabrication by October 1958. Of the 13 steps, 11 were 

to be performed in a glovebox. Fabrication was performed in Buildings 235-F and 773-A in October 

1958 in very small-scale demonstrations. The slugs were irradiated at the Materials Testing Reactor 

and the K Reactor. In November 1958, a 1/1,000-scale agitated-bed anion exchange resin system 

was set up in the laboratory. The process was satisfactorily demonstrated in the laboratory using one 

irradiated neptunium oxide slug (DuPont 1958a). The recovery of irradiated neptunium was tested in a 

high-level cave at Building 773-A (Burney and Karraker 1958; DuPont 1958a). To develop a 

procedure for preparing neptunium oxalate, experiments were conducted using 100 mg (-0.7 μCi) of 

"Oak Ridge" neptunium that contained small amounts of plutonium and iron (Pollock and Walz 1958). 

Testing continued in Building 773-A from January through April 1959. Staff training on the recovery 

procedure was performed at that time. By July, 70 g of 237 Np had been recovered from dilute 

solutions using the test set-up in Building 773-A (DuPont 1959a). The workflow for producing 238 Pu 

was developed using some of that recovered neptunium.

As discussed in the following sections, SRS recovered neptunium using different waste streams 

through 1984 and in the H-Canyon starting in the 2000s (DuPont 1980a; Fuller, Smith, and Goergen 

2013; Taylor and Phifer 2012). Between these dates, neptunium in reactor waste streams was sent to 

waste tanks. A diagram of the movement of neptunium material being processed at SRS is shown in 

Figure 2-1.
 

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Figure 2

-1. Neptunium material flow (DuPont 1984a).

67
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2.1 RECOVERY FROM IRRADIATED URANIUM

Experimental equipment for testing the feasibility of neptunium recovery from HAW was designed and 

ready for use by July 1958. In August 1958, small-scale experimental equipment to establish the 

feasibility of neptunium recovery from acidic HAW was installed in the H-Canyon. The first test in 

H-Canyon was performed in September 1958. Testing revealed that, with one modification to the 

plutonium-uranium (PUREX) process, nearly all neptunium in the irradiated depleted uranium feed 

appeared in the 1AW high-level waste from which it was recovered by ion exchange. Wastes from 

PUREX streams and from the neptunium purification steps were combined and concentrated and 

therefore represent essentially all of the neptunium present in the PUREX plant feed (Poe, Joyce, and 

Martens 1963). High-level waste streams containing neptunium were concentrated by evaporation in 

preparation for neptunium recovery via anion exchange using new modular equipment installed in FCanyon. Recovered 239Pu was returned to the second plutonium cycle (Poe, Joyce, and Martens 

1963; WSRC 2000).

A diagram of the PUREX process is provided in Figure 2-2. Production recovery of neptunium using 

the modified PUREX process was performed in the F-Canyon (WSRC 2000). Small modular units 

called “frames” were used in the canyons for the neptunium separation. Once an adequate 

neptunium inventory was accumulated by 1965, isolation and recovery of neptunium from the PUREX 

process was discontinued (WSRC 2000).

Figure 2-2. Modified PUREX process for recovery of neptunium source

(Poe, Joyce, and Martens 1963).
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Representative results for recovery in January 1963 for the modified PUREX process are shown in 

Figure 2-3 (DuPont 1963a). Less than 1% of the neptunium processed in the 221-HB Line came from 

the PUREX process in F-Canyon (Epperson 1996).

Figure 2-3. Neptunium recovered from PUREX waste, January 1963 (DuPont 1963a, p. 140).

SRS used a modified PUREX method (known as the HM Process) to process radioactive waste 

streams from enriched uranium irradiation. The HM Process was also modified (1) to recover 

neptunium by isolating most of the neptunium in a new 1BP (1BP Aqueous Product from 1B Bank in 

First Cycle Solvent Extraction) stream, and (2) to reduce the loss to the 1AW stream by adjusting the 

1AF stream with additional ferrous sulfamate. The flowsheet for recovering neptunium from enriched 

uranium is shown in Figure 2-4. The 1B mixer-settler was placed in service to partition the neptunium 

into a uranium-free 1BP stream. Production recovery of neptunium from enriched uranium was 

performed in the H-Canyon. The neptunium product solution was concentrated by evaporation in 

preparation for further processing in HB Line in Building 221-H (Poe, Joyce, and Martens 1963; 

WSRC 2000). On limited occasions, SRS shipped neptunium it recovered from the enriched stream 

to the Hanford site (Tetzlaff 1960a) and the Oak Ridge National Laboratory for further recovery 

(DuPont 1961a, 1963a; Tetzlaff 1960b).

2.2 RECOVERY FROM IRRADIATED NEPTUNIUM TARGETS

Irradiated neptunium oxide targets (originally in a slug design but later changed to a tube) contained 

unconverted 237 Np, reactor product 238 Pu, and fission products. Due to the fission product activity,

irradiated targets were cooled at least 45 days to allow decay of the short-lived fission products. 

Dissolution of targets required up to 48 hours and then only about 85% dissolution was obtained. 

The remaining dissolved target material was carried over and dissolved with the subsequent

batches of targets. Approximately 8 to 10 kg/mo of neptunium were recovered from dissolved

irradiated targets during the duration of the process (WSRC 1996ESH-HPT-96-0117). There was

significant plutonium contamination.

Anion exchange was used to separate aluminum, remaining fission products, and other impurities 

from the 238Pu product and residual 237Np. Plutonium and neptunium were absorbed by the resin 
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Figure 2-4. Process for neptunium recovery from enriched 

uranium (Poe, Joyce, and Martens 1963).

column to separate them from aluminum, fission products, and other cationic impurities. Plutonium

was separated from the neptunium by washing the column with nitric acid containing ferrous 

sulfamate and hydrazine to reduce the plutonium to the (Ill) valence state. The separated neptunium 

and plutonium were processed by one or more additional cycles of anion exchange, as needed, to 

obtain the required purity of 238Pu and 237 Np (WSRC 2000). The specification for 238Pu was a 

minimum of 2 g/L (Poe, Joyce, and Martens 1963).

Processing of irradiated neptunium targets was initially performed on a small scale in the high-level

caves at Building 773-A. Due to very high radioactivity levels associated with the neptunium and

plutonium, novel techniques of equipment installation were employed in the heavily shielded

separations processing areas, specifically in H-Canyon where irradiated targets were processed. A 

frame assembly similar to the ones used in F-Canyon was installed in H-Canyon for neptunium

recovery from irradiated targets. The flowchart for the recovery of neptunium and plutonium from

irradiated neptunium targets is shown in Figure 2-5. The HB Line was modified to provide facilities for 

converting purified 238Pu product and the recovered 237 Np to the final oxide forms.

2.3 CONVERSION TO NEPTUNIUM OXIDE

Nitric acid solutions of recovered neptunium were transferred to the HB Line, a lightly shielded, 

glovebox facility in Building 221-H. These solutions were converted to neptunium oxide (NpO2) to be 
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Figure 2-5. Process for recovery of neptunium from irradiated targets (Groh, Poe, and Porter 2000, p. 

181).

fabricated into targets for neutron irradiation to produce 238 Pu. Neptunium received directly from 

Hanford in roughly 1-kg quantities was also processed in the HB Line in 1967 through 1972 (Kelley 

1969). Neptunium was further purified and concentrated in the HB Line, if needed, by anion 

exchange (WSRC 2000).

The scrap recovery module consisted of two parallel lines of gloveboxes located over Section 2 and 

Section 3 of the canyon. They provided the capability for introducing different types of scrap 

materials and for the sorting, dissolution, filtration, and transfer of solutions to the canyon for actinide 

recovery and associated support capabilities. These lines were equipped with water jackets and lead 

shielding over the gloves along with leaded glass on the windows to shield the operating staff from 

gamma radiation (WSRC 2000).

In the HB Line, neptunium was finished in the old B-Line cabinets. A new HB Line facility was 

constructed in the early 1980s on top of Building 221-H. The new line had three subparts: one for 

neptunium, the second for 238Pu, and the third for neptunium and plutonium recovery from scrap. This 

new facility was located over Sections 2 through 6 of Building 221-H on the fifth and sixth levels. A 

new neptunium oxide line was constructed over Sections 4 and 5 of the 221-H-Canyon. The oxide

line consisted of two glovebox lines constructed with adjacent operating and maintenance rooms to 

minimize spread of contamination. Neptunium nitrate was decontaminated and converted to NpO2
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using the same technique described in the preceding paragraph (Fuller, Smith, and Goergen 2013). 

However, the new HB Line was not used to process 237 Np until 2004 (Koenig 2013).

3.0 FABRICATION OF NEPTUNIUM TARGETS

After finishing in HB Line, neptunium oxide was transferred to Building 235-F to be blended with

aluminum powder and fabricated into irradiation targets for SRS reactors. Neptunium oxide shipments

to Building 235-F would typically be in batches of about 1 kg each with total shipment weights ranging

between 2 and 25 kg (DuPont 1977a, 1977b, 1977c, 1977d). Batches of neptunium oxide from HB

Line were contaminated with 238 Pu. Representative assays by 238 Pu weight percent are provided in

Table 3-1.

Table 3-1. Plutonium contamination from HB Line. 

NpO2

(kg)

Minimum 

Pu wt%

Average 

Pu wt%

Maximum 

Pu wt% Reference

21.8 <0.05 0.16 0.6 DuPont 1974a

4.84 0.18 0.36 0.53 DuPont 1974b

12.65 0.02 0.18 0.42 DuPont 1974c

5.25 0.01 0.03 0.06 DuPont 1974d

2.25 0.25 0.28 0.32 DuPont 1974e

Such plutonium contamination is important to note because as the plutonium-to-neptunium ratio 

increases the plutonium becomes the alpha emitter of radiological concern as demonstrated in 

Table 3-2 assuming specific activities for 238Pu and 237Np of 17.1 Ci/g and 0.00069 Ci/g, respectively.

Table 3-2. Alpha ratio.

Np

wt%

Pu 

wt%

Pu:Np 

alpha ratio

99.0 1.0 250:1

99.5 0.5 125:1

99.9 0.1 25:1

99.95 0.05 12:1

99.99 0.01 2.5:1

99.995 0.005 1.2:1

99.999 0.001 0.25:1

The first target, in the form of a canned slug, was fabricated at SRS in 1961. The slug consisted of a 

compacted blend of neptunium oxide and clad in an aluminum can. Groh, Poe, and Porter (2000) 

reported:

“Green” compacts, 3 inches long and 0.86 inches in diameter, were formed by pressing 

the blended powder in a tool-steel die at 19.8 tons per square inch at ambient 

temperatures. These compacts were 90 to 92% of theoretical density. A double-acting 

press was used since it transmits equal force to both ends of the compact to give more 

uniform compaction. Complete densification during green compact fabrication was 

undesirable since some travel of the compact surface relative to the can wall during hot 

pressing is needed to provide a fresh metallic surface for bonding.

Figure 3-1 compares the sizes of the neptunium operations (one room) with plutonium fabrication

operations (Rooms 7, 8, 9, 11 and 13). Note the neptunium line, which is below Vault 100, is

divided. The top part was the maintenance side while the bottom was the operations side. The two

sides were separated by walls. A photograph of the production side of the neptunium billet line 

showing production operators and supervisors is shown in Figure 3-2. A view of the maintenance side 

of the line is shown in Figure 3-3.
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Figure 3-1. Building 235-F layout (Taylor and Phifer 2012).

Figure 3-2. Workers on the neptunium billet line, Building 235-F 

(DuPont ca. 1975a).

In Building 235-F, two compacts were loaded into an impact-extruded aluminum can and capped. 

These components made up a slug. The slug was then loaded into an industrial die that was placed in 

a vacuum furnace. This furnace, enclosed in a glovebox line, consisted of a floating back-up die inside 

a stainless-steel sheath wrapped with resistance heaters (Figure 3-4).
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Figure 3-3. Maintenance side of the neptunium billet line, 

Building 235-F (DuPont ca. 1975b).

Figure 3-4. Hot-press-bond furnace for fabrication of neptunium target 

slugs (WSRC 2000).

After hot pressing, slugs (with the flash intact) were cleaned in a hot caustic solution to remove any 

residual surface lubricant, then rinsed in cold water. Slugs were dipped in nitric acid to neutralize 

caustic agents and to remove surface smut left by the caustic etch, then given a final rinse in cold 

water. The entire procedure was repeated in a second set of baths to remove residual surface 
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contamination. Slugs were dried before the flash was trimmed. Slugs were trimmed to remove the 

flash and to prepare the top end for a weld. A gauging dimple was pressed into the top end caps 

during hot pressing so slugs could be trimmed and rewelded several times, if necessary. The welds 

served two purposes: they offered an inspection step for the soundness of the top end cap and also 

served as a final closure on the slug (Hill 1961). All of these operations were performed in gloveboxes 

with contained atmospheres for worker protection. The target slugs were irradiated between 1961 and 

1965 to produce 238Pu; the first 238Pu was produced at SRS in 1961 (WSRC 2000).

In the mid-1960s, the design of the neptunium target was changed to unalloyed tubular elements as 

more neptunium became available for irradiation (DuPont 1965a; WSRC 2000). The extrusion

process for neptunium-aluminum (Np-Al) tubes was developed in Building 773-A in 1966 (DuPont 

1967a). First, prototype elements containing thorium oxide were substituted for neptunium oxide and 

were fabricated with dimensions of the Mark VI-N element (DuPont 1984b). The tubular design 

improved heat transfer, which increased production and purity of the 238Pu by allowing operation at 

higher neutron fluxes. The exact designs of the tubular element were modified three times between 

1966 and 1978. The target designs used differing amounts of neptunium so that the final tubular 

targets varied from 120 to 190 g of neptunium per foot of active tube length, and the tube diameter 

varied between 3 and 3.7 in.

Starting by 1968, billets were also fabricated into alloyed tubes in Building 235-F. Billets consisted of 

cylindrical inner and outer sleeves welded to the bottom fitting. To create a contamination shield, 

billets were placed in the space between the two sleeves. A top fitting with a breather tube was 

welded in place. Starting in 1966, the use of the contamination shield allowed the billet to be removed 

from containment cabinets in Building 235-F and transported to Building 321-M for outgassing and 

extrusion (DuPont 1960a, 1961b, 1961c, 1962, 1966a, 1968a, 1969a, 1969b,c, 1971a, 1975a, 1976a, 

1976b, 1977e, 1977f, 1978a; Reed 1982; Roggenkamp 1987). Before extrusion, the billet assemblies 

were subjected to off-gassing in ovens. After extrusion, tubes would undergo fluoroscopic examination 

in 321-M using the fuel distribution analyzer and be re-extruded, if necessary (Osmond et al. 1984; 

DuPont 1977b, 1977c, 1977d, 1977g, 1977h; Reed and Swanson 2006). At times, neptunium fuel 

tubes underwent metallurgical testing in gloveboxes in Building 322-M (DuPont 1969d, 1974f); at other 

times, testing was performed in 773-A (DuPont 1974f). Fuel-density measurements were made with 

the fuel density analyzer in 321-M, and with the nuclear test gauge in 305-M (DuPont 1970b, 1974b; 

Reed and Swanson 2006). While not a normal part of the neptunium process, some of neptunium 

oxide tubes were sawed in 321-M (DuPont 1975a).

When neptunium was extruded in Building 321-M, the extrusion portion of the building was shut off 

from normal access and workers dressed in protective clothing (Reed and Swanson 2006). Billets 

were heated and stretched into reactor targets. Although this was a physical process, no machining 

such as cutting or grinding was done. If the billet maintained its integrity throughout the extrusion, no 

contamination would be present. However, because the Machining and Casting Area of 321-M was a 

known contamination area at SRS, it is plausible to assume that some failures occurred during the 

extrusion of materials, including those containing neptunium. Uranium and neptunium billets were 

processed with the same equipment and, in comparison with uranium, a relatively small amount of 

neptunium was processed through 321-M. Therefore, it is reasonable to assume that any neptunium 

contamination is not isolated from the uranium contamination. According to the Waste Information 

Tracking System database, in 321-M, the activity fraction for 237Np was less than 0.1 %; no 238Pu was 

listed (Epperson 1996).

The number of neptunium tubes extruded was only a small fraction of the tubes extruded in Building 

321-M. Table 3-3 compares the number of neptunium, depleted uranium, and enriched uranium tubes 

extruded from 1968 through 1975. Figure 3-5 shows a photo of the front of the extrusion press.
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Table 3-3. Comparison of tubes extruded in Building 321-M 

(Reed and Swanson 2006).

Year

Neptunium 

tubes

Depleted 

uranium tubes

Enriched 

uranium tubes

1968 28 67,739 11,944

1969 300 67,951 12,538

1970 0 144,631 17,735

1971 78 66,483 7,318

1972 87 119,170 5,433

1973 0 177,468 No data available

1974 66 96,344 3,422

1975 103 83,202 3,457

Figure 3-5. Front entrance of extrusion press, Building 321-M (Bebbington 

1990).

Fabrication of neptunium targets was suspended from October 1979 through April 1980 while SRS 

used the neptunium billet line and related processes to make plutonium targets for the 242Pu program 

(DuPont 1980b, 1980c). After being restarted, fabrication of neptunium targets was continued until 

1984 (DuPont 1980a; Rogers et al. 1989; Fuller, Smith, and Goergen 2013; Jordan, Watkins, and 

Hensel 2009). Twelve MK 53A billets (high NpO2 content) were extruded in December 1980 for testing 

neptunium loading (DuPont 1980a). 

Figures 3-6 shows two photos. On the left, a billet is forced into the extrusion die. On the right, a billet 

as it emerges from the press.
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Figure 3-6. Front entrance and rear exit of extrusion press, Building 321-M (Bebbington 1990).

Seven of the SRS fuel element designs included 237Np for irradiation: 

• Mark VII-A and VI-J (both briefly in 1961), 

• Mark VI-N, 

• Mark 52, 

• Mark 53, 

• Mark 53A (some), 

• Mark 53B, and 

• Mark 61 (DuPont 1961c, 1984b).

In 1987, SRS reported a 237Np inventory of about 400 kg with the capability to produce about 80 kg/yr 

(Roggenkamp 1987); however, active operations for separating and fabricating neptunium had been 

stopped in 1984 (Fuller, Smith, and Goergen 2013).

4.0 NEPTUNIUM OPERATIONS AFTER 1984

With the shutdown of neptunium and 238Pu separation and fabrication in 1984, the equipment used in 

H-Canyon was decontaminated, although other separations continued in H-Canyon until 1992. Once 

decontamination was completed, SRS conducted a project to upgrade the H-Canyon frames process 

equipment but ceased before completion. Most of the H-Canyon frames process services, 

instrumentation, and support equipment were upgraded, but the actual canyon frame modules were 

not installed. As of 2013, this equipment was still stored as spare equipment and is available for 

installation. The Building 235-F facilities were left in “enhanced production readiness” status from 

1985 through 1990 with maintenance activities being performed by just three operators. Varying levels 

of maintenance activity were carried out between 1985 and 1990, primarily on the building ventilation 

system (DOE 1991). Neptunium was stored in 235-F through 1998.

Building 321-M was removed from operation in 1992 (Reed and Swanson 2006). In 1995, it was 

decommissioned, and decontamination was started in 2000 (Dewberry 2004a). During 

decontamination operations, 237Np hold-up contamination was measured in the outgassing ovens. 

SRS staff indicated the appearance at the measured level of 237Np was not inconsistent with the 

designated solid waste stream for the facility, but the measurements were verified (Reed and Swanson 

2006) because furnace-heating of 237Np was not performed in 321-M (Dewberry 2004b). 
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However, outgassing of neptunium fuel was conducted in 321-M (Reed and Swanson 2006). A 

subsequent survey found low-level 237Np contamination on two saw bench components. The saw 

benches were used to cut process components, primarily U-Al product fuel tubes (Dewberry 2004c), 

but had also been used to cut neptunium tubes (DuPont 1975a).

Nine surplus 237Np targets were being stored in the Building 321-M vault in the 1990s, and 6,100 L of 

solution containing 237Np were being stored in H-Canyon holding tanks through 2003 (Brock and Craig 

undated; Watkins, Hensel, and Jordan 2010). The latter material represented the neptunium 

recovered and purified in the 1980s. The nine targets were moved to K-Area for storage until they 

were processed in H-Canyon for recovery of neptunium by 2004 and converted to oxide in the HB Line 

(Koenig 2013). Between 2004 and 2008, neptunium from the H-Canyon holding tanks was also 

separated in the H-Canyon and converted to an oxide in the HB Line. Fifty cans of neptunium oxide 

were produced and shipped to Idaho National Laboratory (Rudisill 2002; Jordan, Watkins, and Hensel 

2009). Additional small quantities of 237Np resulted from H-Canyon closure operations with the 

processing of irradiated uranium fuel (Walker et al. 2003). These solutions were also converted to 

oxide. These oxide materials were shipped to Idaho National Laboratory and Oak Ridge National 

Laboratory in the approved type 9975 shipping containers (Watkins, Hensel, and Jordan 2010).

5.0 ANCILLARY WORK

From the start of operations through 2007, SRS has performed laboratory analysis, experiments and 

tests, fuel prototype fabrication, and test irradiations using 237Np. These activities were conducted in 

several buildings including 773-A, 777-M, 305-M, CMX, TNX, and 772-F. Several of these operations 

were performed routinely throughout the course of reactor operation; others were research and 

development (R&D) tasks. An overview of work items, locations, and years of operation by building 

are provided later in Table 5-1. Some highlights of these items include:

• Experimental equipment for testing the feasibility of recovering neptunium from HAW in the 

canyons (Building 773-A, 1958) (DuPont 1958a).

• Testing of the use of agitated beds of anion exchange resins (Building 773-A, 1958) (DuPont 

1958a).

• Routine analyses for neptunium in process streams (Building 772-F, 1959) (DuPont 1959b).

• Evaluation of mechanical stirrers (Building 772-F, 1960) (DuPont 1960a).

• Laboratory-scale testing of neptunium separations (Building 773-A, 1961) (DuPont 1961b).

• Laboratory development and completion of a process for recovering about 90% of the 

neptunium from samples of stored plant wastes (Building 773-A, 1961) (DuPont 1961d).

• Measurements on 105 neptunium oxide slugs and 3,531 Mark V-B slugs (Building 773-A, 

1963) (DuPont 1963a).

• Tests in the Process Development Pile to determine the reactivities and power ratios for 

assemblies containing tubular neptunium target elements (Building 777-M, 1965) (DuPont 

1965b).

• Neptunium oxide slugs formed and fabricated into billets (Building 773-A, 1968) (Moyer 

1969a).
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• Requests by Separations Technology for laboratory assistance in studying possible causes of 

neptunium losses in the 2B bank of the second neptunium cycle (Building 772-F, 1969) 

(DuPont 1969d).

• Flow test of new tubular NpO2 assembly (CMX, 1969) (DuPont 1969e).

• Development techniques for fabricating aluminum-clad 237Np target tubes with cores of mixed 

Mg-NpO2 powders (Building 773-A, 1970) (DuPont 1970b).

• Testing of techniques for improving the purity of 238Pu from 237Np (Building 773-A, 1971) 

(DuPont 1971b).

• Completion of pressurized and unpressurized anion exchange tests with macroporous 15% 

cross-linked resin (Building 773-A, 1972) (DuPont 1972a).

• Nondestructive X-ray fluorescence testing of residual cladding thickness on two Mark SJA 

(NpO2) tubes (Building 773-A, 1978) (DuPont 1978b).

• Program begun to develop a method for removing NpO2 from waste rags from compact line 

cabinets in Building 235-F. This method reduced the amount of neptunium shipped to the 

burial ground. Over 1, 200 g of neptunium in Building 235-F solid waste had been buried from 

January 1973 through July 1975 (Building 772-F, 1975) (DuPont 1975a).

• The Building 321-M extrusion press was returned to service August 16, 1976, after a 5-week 

shutdown that included maintenance work to correct tooling misalignment that caused 

excessive tube eccentricity (DuPont 1976c). 

• Development of a solvent extraction flowchart for processing 237Np and 238Pu as a possible 

replacement for anion exchange processing (Building 773-A, 1977) (Thompson and 

Thompson 1977).

• Encapsulated neptunium tubes analyzed for fuel density at the Building 305-M nuclear test 

gage, a light-water moderated subcritical reactor (DuPont 1976a, 1977b, 1978e, 1979a).

• 69 g of neptunium oxide shipped from HB Line to Building 773-A in December 1980 for use by 

the Actinide Technology group in the evaluation of the proposed neptunium process for the 

new H-Area B-line facilities (HB to Building 773-A, 1980) (DuPont 1980d).

• Tests of fission product content, nuclides present, and the plutonium content in NpO2 to 

determine the shielding required to minimize personnel exposure in design of the new HB Line 

facility (Building 772-F, 1980) (DuPont 1980e). 

• Research performed in a mini-mixer settler to achieve adaptation of the uranium(IV) reductant 

to the SRS PUREX processes (Building 773-A, 1986) (Orebaugh 1986).

• The Analytical Development Section developed a method to measure 237Np holdup in "hot 

spots" in Building 235-F. The method was based on exposure readings in places where the 

background was too high to use gamma-pulse-height analysis [Savannah River Laboratory 

(SRL)], 1992) (Ferrell 1992).

• SRL researched methods for, and properties of, options for dissolution of neptunium oxide 

residues with the goal of running the method in H-Canyon (SRL, 2008) (Kyser 2009).
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• SRL performed a laboratory-scale experiment to test a method for dissolution of nine 

unirradiated targets with the actual dissolution to be performed in H-Canyon (SRL, 2002) 

(Rudisill 2002).

• 98 g of neptunium oxide were produced on a bench scale from the same feed solution source 

for the gas generation studies (Building 773-A, 2003) (Duffey 2003a, 2003b, 2003c). 

• SRL developed a dissolution flowchart for neptunium oxide residues (i.e., various NpO2

sources, HB Line glovebox sweepings, and SRL analysis samples). Samples of each type of 

material proposed for processing were dissolved in a closed laboratory apparatus; the rate and 

total quantity of offgas were measured (SRL, 2008) (Kyser 2009; Watkins, Hensel, and Jordan 

2009).

• Rapid separation method developed for 237Np and plutonium isotopes in large soil samples 

(Building 773-A, 2010) (Maxwell, Culligan, and Noyes 2013).

• SRL investigated the neutralization and transfer of neptunium slurry from canyon wastes to the 

tank farm (SRL, 2011) (Walker et al. 2003).

Table 5-1. Ancillary work. 

Building Work Year Reference

305-M 

(NTG)

Density analysis 1960–1984 DuPont 1974b, 1974d, 1976a, 

1977b, 1977c, 1977g, 1978c, 

1978d, 1979a; Reed and Swanson 

2006

736-A Calibration of 1.1 g neptunium source 1960 DuPont 1960b

772-F Routine analyses for neptunium in 

process streams

1953–2007 DuPont 1959b, 1978b; Weinheimer 

2012

772-F Analytical development work 1958–1984 DuPont 1958b, 1975a, 1980f, 

1980g; Ferrell 1992

773-A Cold runs of Pu-238 production using 

neptunium in high-level caves \

1959 DuPont 1957b

773-A Chemistry work; research 1955–2011 DuPont 1957c, 1965c; Pollock and 

Walz 1958; Moyer 1966a

773-A Shipping of neptunium to other sites 1960–1967 Tetzlaff 1960c; Moyer 1966a; 

DuPont 1967b

773-A Laboratory-scale testing of canyon 

equipment and processes

1958–2008 DuPont 1957b, 1958a, 1959a, 

1961b, 1961e, 1961f, 1965c, 

1968a, 1969f, 1971c, 1972a, 

1972c, 1974g, 1977b, 1978b, 

1980d; Rudisill 2002; Kyser 2009; 

Caracciolo 1961; Ice 1966; 

Thompson 1977; Orebaugh 1986; 

Duffey 2003c; Burney and Karraker 

1958; Walker et al. 2003

773-A Testing of Np fabrication 1961–1978 DuPont 1961c, 1962, 1963a, 

1970b, 1968e, 1971b, 1974f, 

1979a; Moyer 1969a; Marter 1961

777-M Procedure tested to use 20 mg Np-237 1955 Hyde 1955

777-M Irradiation of Np foils 1965–1968 DuPont 1965b; Copley and Moyer 

1968a

CMX Flow test of Np oxide fuel assembly 1969 DuPont 1969e

TNX Tests of recovery processes 1958–1960 DuPont 1957b, 1958b, 1960c, 

1960d
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6.0 TIMELINE

The major neptunium processes and associated ancillary activities are presented in Figure 6-1. The 

timeline of neptunium processes and ancillary tasks by area and building from 1960 through 2010 are 

presented in Figure 6-2.

Figure 6-1. Neptunium process flowchart. (based on DuPont 1984a).

7.0 INVENTORY

The ORAU Team obtained data on 237Np at SRS from DOE’s Nuclear Materials Management and 

Safeguards System (NMMSS). The data include neptunium inventories from 1966 through 2012. The 

data supplied by DOE was maintained by “compcode” rather than location. The ORAU Team 

analyzed the data by the compcode description to subjectively map each of codes to one of the 

particular SRS process categories: Canyon Feed, HB Line, Fabrication, Reactor, and Lab. These 

categories do not include waste processes, but do include neptunium storage.
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Figure 6-2. Neptunium process timeline. 

The ORAU Team summed the quantity amounts (grams) across the code entries for each of the five 

process categories by the last month of each reported calendar quarter. Activities for each process 

category by month were calculated using the specific activity of 6.9 × 10-4 Ci/g (Plexus-IEM 2016). 

Figure 7-1 shows inventories by major process plotted by ending date of calendar quarter. A large 

spike is shown for recovery from 1993 through 2007, but much of that material was in feed storage. 

Neptunium assigned to conversion, fabrication, and reactors after 1988 was also in feed storage until 

2004 when the neptunium recovery and conversions were performed in H-Canyon and the new HB 

Line (Rudisill 2002). The activity amount of neptunium assigned to laboratories was quite small in 

relation to the feed and does not show in Figure 7-1.

0

50

100

150

200

250

300

19661969197119741976197819791981198319851987199119931995199719992000200220042006200720092011

Feed

HB Line

New HB Line

Fabrication

Reactors

Labs

Figure 7-1. Neptunium by activity (Ci) by major process. 

The NMMSS data cannot be used to determine specific amounts of 237Np by exact work location at a 

given time. However, it is apparent from other inventory data that some portions of neptunium 

inventories reported for dissolution and recovery and the HB Line were used in the actinide technology 

program at Building 773-A, Rooms B114, B115, and C155 (Brown 1983; Jowers 1984). Furthermore, 
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some portions reported for fabrication were used and stored at both Buildings 321-M and 773-A 

(Brown 1983). Actinide technology was largely involved with the chemistry of uranium, plutonium, and 

neptunium; ion exchange and solvent extraction development; mixing, filtration, and precipitation 

research; chemical and engineering studies of separation processes; process waste minimization; and 

power source development for space application.

8.0 RADIATION SAFETY AND MONITORING

SRS used radiological controls with the neptunium handling processes to reduce the potential for 

radiation exposure. The SRS Health Physics organization monitored neptunium work since its 

inception. The ORAU Team has reviewed SRS Works Technical Division monthly reports and health 

physics periodic reports to identify radiological controls and specific instances of occupational radiation 

monitoring. Routinely, highlights and summaries of information were included in such reports, while 

more detail and data from additional monitoring was provided on survey data forms. Radiological 

control of neptunium and other radionuclides was mandated by procedure DPSOP-40 and Special 

Hazards Bulletins (DuPont 1961h, 1972b).

8.1 RADIOLOGICAL CONTROLS 

All canyon maintenance work was designed to be done remotely (ORAUT 2013a, 2013b). New 

equipment was installed in F- and H-Canyon facilities. The original equipment and subsequent 

replacement parts were first tested in a nonradioactive mock-up shop section of each canyon 

(Fernandez 2000). Small modular units called “frames” were installed by skilled workers using novel 

techniques in a canyon space approximately 10 ft square by 17 ft high with a standard arrangement of 

pipe nozzles to supply services in both F- and H-Canyons to process waste streams and irradiated 

targets. Within the frames in F-Canyon, four ion exchange columns were installed.

In H-Canyon, five columns and a dissolver were installed for neptunium-plutonium separation from 

irradiated neptunium targets. The size of the ion exchange columns was small in comparison with 

regular canyon equipment; this permitted development of a concept in which a number of columns and 

tanks could be mounted in a frame that could be installed as one modular unit. The canyon frames 

were installed in modules 10 ft square by 17 ft high with standard services (i.e., inlet and outlet piping, 

steam, cooling water, electricity, sampling, and instruments). The modules were isolated by a low curb 

to contain liquid spills or leaks, and had a sump and a permanently installed transfer jet to move spilled 

liquids or leakage to a rework system. Installing multiple items in a frame was considered an 

economical use of canyon space, but it also entailed a burden when providing services to a module. 

Pipe and electrical connections were made to the frame using conventional canyon jumpers rather 

than to individual pieces of equipment. Electrical and other services were piped to equipment pieces 

as part of the permanent frame structure. Additional services were required though, primarily for 

pneumatic liquid level and specific gravity instrumentation for the several vessels in each frame. 

Bundles of up to six small, stainless-steel tubes were drawn through 3-in. pipes embedded in the 

canyon shielding walls. No significant problems were reported for the installation of these lines or their 

use (Poe, Joyce, and Martens 1963; WSRC 2000; Overbeck, Ice, and Dessauer 1965). In 2000, Groh, 

Poe, and Porter (2000) reported that the useful life of the frames was equivalent to the life of 

embedded piping. A photo of a canyon frame is shown in Figure 8-1.

The ion exchange columns used in neptunium recovery were either 12- or 24-in. in diameter and 

normally contained 25 or 100 L of resin. By design, they were used as conventional settled-bed ion 

exchange columns, but they could also be used as agitated ion exchange bed columns. One unit was 

used routinely as an agitated bed column. All maintenance operations were performed remotely 

without mechanical valves, including resin replacement. There were sometimes events that resulted in 

contamination. Those were resolved remotely. For example, in June 1962, solution from a 237Np238Pu 

raw metal process filter drained through an embedded line to a blanked flange on the outside canyon 
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Figure 8-1. Neptunium-plutonium 

frame without ion exchange 

columns (Groh, Poe, and Porter 

2000).

wall. A prefabricated 3-in. lead shield was remotely installed over the portion of the line, which 

extended 6 in. from the canyon wall. The shield reduced the radiation level from 5 R/hr to 30 mR/hr at 

2 ft from the flange. Equipment to permit remote decontamination of the embedded pipe from inside 

the hot canyon was used to clean up the contamination (DuPont 1980h).

Two weirs determined flow paths. Air pressure was applied to either or both to direct flow properly for 

feed, wash, elution, or resin removal depending on the task. Dowex 1 and Permutit SK anion 

exchange resins were used in the columns (Hill 1961). Dowex 1 resin provided higher

decontamination from fission products, while Permutit SK resin was more stable with alpha radiation. 

Selected use of smaller particle resins were used where fast kinetic absorption was required, such as 

in the ion exchange column used for separation of 238Pu from 237Np. A diagram of an ion exchange 

column used in the process is presented in Figure 8-2.

The original HB Line was also modified to provide facilities to convert the purified 238Pu product and the 

recovered 237Np to the final oxide forms. Neptunium-237 and 238Pu finishing operations were 

performed in HB Line gloveboxes. The 238Pu operations were performed in a new small glovebox line, 

but the neptunium was finished in the old B-Line cabinets and gloveboxes. A new HB Line, 

constructed over Sections 2 through 6 of H-Canyon, was designed with three functional areas: (1) 

purification of neptunium; (2) purification of 238Pu; and (3) recovery of neptunium and plutonium from 

scrap. The new neptunium oxide line, placed in use by 1984, was constructed over Sections 4 and 5 

of the 221-H-Canyon. All work with 237Np was performed in two glovebox lines constructed with 

adjacent operating and maintenance rooms to minimize spread of contamination. The gloveboxes 

contained ion exchange columns and equipment to precipitate, finish, and package neptunium oxide 

for shipment to Building 235-F for target fabrication.
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Figure 8-2. Ion exchange column (Groh, 

Poe, and Porter 2000).

A structure referred to as a cabinet (a small glovebox line) was used in Building 235-F to process 

neptunium oxide. A cabinet was a ventilated, walled, shielded glovebox. The neptunium billet room 

was posted as a Regulated Radiation Area. Shadow shielding was used due to high gamma dose 

rates. All process work in 235-F was done through glove ports. Workers donned anticontamination 

clothing in 235-F as shown in the example in Figure 3-2. Maintenance of the glovebox cabinets was 

performed on the reverse side of the process line in a room walled off from the process area.

Maintenance was performed inside cabinets, but contamination control huts were constructed and

used (DuPont 1974–1984). Workers dressed in protective clothing and gloves appropriate for the task 

to be conducted, as assigned by Health Physics (ORAUT 2013c). Job task analyses were done for all 

nonroutine work. Health Physics reviewed those analyses and added measures necessary to keep 

radiation exposures as low as possible. Measures included but were not limited to contamination huts, 

additional shielding, protective clothing, and health physics surveys of the job. Workers checked their 

hands and feet for contamination before exiting areas where such work was performed.

SRS continued to evaluate radiation exposures and make process and equipment upgrades over time. 

For example, additional shielding was installed on the lubricating cabinet in the neptunium billet line in 

Building 235-A in 1977. At that time only the adjacent die-press cabinet was still unshielded. The lead 

shield and leaded-glass viewing window reduced the body exposure dose rate from 35 to 5 mR/hr 

(DuPont 1977i). Access was controlled to each of the buildings where neptunium was processed 

(ORAUT 2013b, 2013c). Entry into canyon buildings and 235-F was by approved worker only. Special 

nuclear materials were stored and processed in both 235-F and 321-M; as such, those buildings had 

secured access. Workers were required to have Health Physics approval to enter specific neptunium 

work locations (ORAUT 2013b, 2013c).
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The Health Physics organization implemented a radiation work permit process in 1990. Job 

requirements and control of access to the job area were carried out with the use of radiation work 

permits. SRS implemented new radiation control practices in 1990 to comply with DOE Order 5480.11 

(DOE 1988), and updated them over time to comply with:

• 1992 DOE Radiological Control Manual, DOE N 5480.6 (DOE 1992), 

• 1994 DOE Radiological Control Manual, DOE/EH-0256T (DOE 1994), and

• 1995 Occupational Radiation Protection (10 CFR Part 835). 

8.2 WORKPLACE CONTROLS

SRS Health Physics routinely monitored F- and H-Canyons, HB-Line, the 235-F neptunium line, 321-M 

and 773-A for surface and airborne contamination, and they did special monitoring of certain jobs and 

monitoring of contamination incidents. Radiation survey and air monitoring data for each area where 

neptunium was processed are available. Primary areas of radiological concern were the neptunium 

billet line in 235-F, HB-Line, and the extrusion furnace in 321-M. There are extensive air monitoring 

data for Building 235-F. The data that includes results of fixed process, routine, and special samples 

shows that that air concentrations of neptunium were controlled to less than 2 × 10-13 μCi/cm3

, which 

was 5% of the Radioactivity Concentration Guide (RCG) for neptunium, 4 × 10-12 μCi/cm3 (DuPont 

1971–1974). Representative routine, special, and process examples of 235-F air monitoring are given 

in Figures 8-3, 8-4 and 8-5, respectively.

Figure 8-3. Routine air monitoring results, Building 235-F (DuPont 1973–1974).

Airborne activity in 235-F was generally controlled to <0.2 x 10-12 μC/cm3

. Routine and process 

samples were first counted 6 hours after collection and recounted at 24 hours to account for radon. 
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Figure 8-4. Special air monitoring results, Building 235-F (DuPont 

1973–1974).

Health Physics performed daily control surveys in the neptunium billet room. A representative survey 

log is shown in Figure 8-6. 

Representative dose rate surveys for 237Np exposures in Building 773A are provided in Table 8-1.

Completed billets were bagged for transfer to Building 321-M for extrusion. Billets were smeared and 

surveyed by Health Physics before the transfer. A representative billet survey is shown in Figure 8-7. 

The survey shows a high gamma dose rate with a neutron component of about 1%. 

Billets were also surveyed at 321-M when received. A representative survey of received billets shown 

in Figure 8-8.

Extruded tubes were surveyed for dose rate once they came from the oven; a representative survey is 

shown in Figure 8-9.

Tubes made from extrusion of neptunium billets were surveyed before being transferred to the reactors 

for irradiation. A representative survey of neptunium tubes is shown in Figure 8-10.
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Figure 8-5. Process air monitoring results, Building 235-F (Brown 2016).

Figure 8-6. Daily control sheet, Building 235-F (DuPont 1981–1984, p. 87).
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Table 8-1. Health physics surveys in Building 773-A (mrem/hr). 

Month Location

Gross exposure 

rate (γ) at 3 in.

Fast neutron 

exposure rate 

at 3 in. Reference

June 1968 B-130 glovebox 35 Not measured Copley and Moyer 1968b

July 1968 B-130 glovebox 15 Not measured Copley and Moyer 1968c

August 1968 B-130 glovebox 50 Not measured Copley and Moyer 1968d

September 1968 B-130 glovebox 50 Not measured Copley and Moyer 1968e

October 1968 B-130 glovebox 60 Not measured Copley and Moyer 1968g

November 1968 B-130 glovebox 60 Not measured Copley and Moyer 1968f

December 1968 B-130 glovebox 30 Not measured Copley and Moyer 1969a

January 1969 B-130 glovebox 40 Not measured Copley and Moyer 1969b

February 1969 B-130 glovebox 40 Not measured Copley and Moyer 1969c

April 1969 B-130 glovebox 40 5 Copley and Moyer 1969d

May 1969 B-130 glovebox 40 10 Copley and Moyer 1969e

June 1969 B-130 glovebox 30 <1 Moyer 1969b

June 1969 B-151 glovebox 40 Not measured Moyer 1969a

Figure 8-7. Survey of neptunium billets to be shipped to Building 321-M 

(Brown 2014, p. 22).

Figure 8-8. Survey of neptunium billets when received at Building 321-M 

(DuPont 1972d). 
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Figure 8-9. Survey of freshly extruded neptunium tubes at Building 321-M 

(DuPont 1972e). 

Figure 8-10. Survey of neptunium billets when received at Building 321-M (DuPont 

1972e). 

At times, the neptunium billet line was used to fabricate 242Pu billets using the same procedures and 

controls. These billets were also bagged for transfer. A representative survey of 242Pu (Mark-42) 

billets is shown in Figure 8-11. Those surveys reveal a lower gamma dose rate but a higher neutron 

component (about 25% of the total dose rate). Operators on the neptunium billet line wore white 

regulated clothing with both beta/gamma and neutron dosimeters (DuPont 1971–1974). Supervisors 

wore white laboratory coats with shoe covers; they were monitored by beta/gamma dosimetry.

SRS monitored the workplace, equipment, neptunium parts, and jobs to control exposures to 

neptunium. Additional representative examples are provided in Attachment A, Table A-1, for 1966 

through 1980.

8.3 WORKER MONITORING

Monitoring for potential intakes of radionuclides at SRS was mandated and controlled by DPSOL 

193-302 from 1971 through 1988 (DuPont 1971d) and DPSOL 193-211 through 1989 (DuPont 1989). 

Bioassay monitoring was prescribed by work area with sampling frequencies based on exposure 

potential. Twenty-four-hour urine samples were collected from workers for 237Np analysis when a 
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Figure 8-11. Survey of plutonium billets to be shipped to Building 321-M (Brown 2014, p. 19).

positive 238Pu result was obtained, or when requested by Health Physics. According to DuPont 

(1971d), DuPont workers in HB-Line and 235-F were sampled twice per year by plutonium urinalysis 

and annually by chest count. From 1978 through 1989, neptunium process workers in Building 235-F 

were sampled twice per year for plutonium and annually for neptunium intakes. During this period, 

workers in HB Line and radiation workers in Building 773-A were sampled four times per year for 

plutonium by urinalysis. Workers in Building 321 M were sampled annually by plutonium urinalysis. 

From 1990 forward, with SRS implementation of alpha spectroscopy, all F- and H-Area workers were 

sampled by urinalysis for neptunium intakes.

DuPont (1971d) prescribed bioassay requirements for Construction Division workers: one sample 

every year for plutonium and a sample when terminating. That requirement is shown in Figure 8-12.

Figure 8-12. Bioassay requirements, Construction Division (Dupont 1971d).
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While the bioassay control procedures in force from 1971 through 1989 required urine sampling, the 

ORAU Team has obtained data to demonstrate that neptunium workers were monitored for internal 

intakes of 237Np intakes since 1961 (DuPont 1963b, 1964, 1965d, 1966a, 1967a, 1968b, 1970c, 1971e, 

1974h, 1975b, 1980a, 1980h, 1980g, 1980e, 1980d, 1984c, 1985a, 1985b, 1985c, 1985d, 1985e; 

Reinig 1984; Reed 1982). The number of neptunium analyses reported by SRS in Works Technical 

Department reports and the number of results obtained by the ORAU Team from logbooks are listed in 

Table 8-3. The number of 237Np results by area provided in Table 8-4.

Table 8-3. Neptunium urinalysis data.

Year

No. of Np-237 samples identified 

in Works Technical Reports

No. of Np-237 Samples 

Identified in other Pu, Eu, and 

Am Logbooks

1972 22 20

1973 31 17

1974 42 18

1975 Not listed 0

1976 Not listed 0

1977 Not listed 0

1978 Not listed 0

1979 11 1

1980 48* 49

1981 57 19

1982 146 78

1983 22* 25

1984 37* 48

1985 13* 14

1986 No summary report 0

1987 No summary report 0

1988 No summary report 30

1989 No summary report 14

* Only partial data currently available for year.

Table 8-4. Number of 237Np samples by area.

Year 235-F HB Line 321-M 773-A/772-F Other

1972 20 0 0 0 0

1973 16 0 1 0 0

1974 17 0 0 1 0

1975 0 0 0 0 0

1976 0 0 0 0 0

1977 0 0 0 0 0

1978 0 0 0 0 0

1979 0 0 1 0 0

1980 36 0 8 3 2

1981 3 2 9 3 2

1982 36 32 6 3 1

1983 12 4 0 7 2

1984 23 5 16 4 0

1985 7 2 0 3 2

1986 0 0 0 0 0

1987 0 0 0 0 0

1988 5 5 0 16 4

1989 3 0 0 9 2

Totals 178 50 41 49 15
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 34 of 67

In addition to urinalysis data, the ORAU Team has obtained results of in vivo counting which may also 

be used to reconstruct potential 237Np doses.

Positive intakes of radionuclides at SRS were recorded and maintained over the years in an intake 

registry. Through 2002, the registry contained over 5,400 intakes. Of those 5,400 intakes, 14 workers 

received positive intakes of 237Np, with 2 workers receiving more than one neptunium intake. 

Information available for those intakes is presented in Table 8-2 (ORAUT 2008). The first intake was 

by wound in March 1960 by an operator in F-Area. The same worker received two other neptunium 

intakes by wound in Building 235-F. The last intake of neptunium recorded in the version of the intake 

database available to the ORAU Team was also from a wound in May 2000; the location of that 

incident is not available.

Table 8-2. Neptunium intakes (ORAUT 2008).

a

Worker Date

Type of 

Assimilation Area Job Title Comments

1 02/15/1972 Wound 235-F Separations Operator Exposed to Pu-238

1 07/05/1973 Inhalation 235-F Separations Operator Exposed to Pu-238

2 11/08/1974 Inhalation 235-F No information Exposed to Pu-238

3 11/1988 Wound CS Boilermaker Exposed to Pu-238

4 04/1989 Inhalation Old HB Line Carpenter Exposed to Pu-238

5 06/1968 Inhalation 235-F Separations Operator None

6 03/1968 Inhalation F Operator None

6 06/1967 Inhalation 235-F Separations Operator None

6 06/1968 Inhalation 235-F Separations Operator None

7 08/1991 Inhalation 235-F Operator Exposed to Pu-238 

8 10/1961 Inhalation F R&D Supervisor None

9 04/1967 Wound F Technician Possibly 772-F

10 03/1991 Inhalation No information No information D&D period

11 12/1998 Inhalation No information No information D&D period

12 08/1999 Inhalation No information No information D&D period

13 05/2000 Inhalation No information No information D&D period

14 09/1999 Inhalation No information No information D&D period

a. D&D = decontamination and decommissioning.

Internal doses from potential exposure to 237Np may be reconstructed using results of neptunium 

bioassay available for the worker. For unmonitored internal dose, coworker neptunium intakes may be 

used to derive internal dose. The methods for derivation of the initial neptunium coworker data models 

are discussed in ORAUT-OTIB-0081, Internal Coworker Dosimetry Data for the Savannah River Site

(ORAUT 2013d). The ORAU Team used several data sources for the neptunium coworker models. 

For years before 1970, some neptunium urinalysis bioassay data were obtained from SRS laboratory 

notebooks (DuPont 1961–1969, 1969g). These data were assumed to be a complete dataset for this 

period. Neptunium bioassay results available in HPRED were used for 1991 through 1995. The 

ORAU Team has no neptunium bioassay data for the year 1990. Four data sources were available to 

develop a coworker model for use in estimating neptunium exposures for the period from 1970 through 

1990: (1) limited neptunium bioassay, (2) ratio of neptunium from the plutonium bioassay, given that 

plutonium activity is between 2 and 10 times greater than the neptunium activity, (3) interpolation, and 

(4) whole-body count (WBC) data. 

For the analysis of the ratio of neptunium from plutonium bioassay, the ORAU Team reviewed monthly 

issues of SRS Works Technical Reports available for 1968 through 1982. In each monthly report, 238Pu by weight or weight percent was reported as a primary contaminant in 237

Np feeds from the 

frames from HB Line and in the product from 235-F. By procedure, SRS considered 237

Np to be 

contaminated with 238Pu, generally at 0.01 wt% (100 ppm) or greater. The available records indicate 

only one instance where SRS produced 237

Np with less than 0.01 wt% 238Pu. SRS reported that one 
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 35 of 67

 

special product of 200 g 237Np with about 10 ppm (0.001%) 238Pu contamination was produced in 

September 1974 (DuPont 1974i). By July 1973, SRS mostly reported the minimum weight percent of 

238Pu as less than 0.05% in monthly Works Technical Reports. The concentration of 238Pu 

contamination found in 237

Np feeds was reduced starting in spring 1974 with the gradual 

implementation of a new macroporous resin for anion exchange into 1975 (DuPont 1974c, DuPont

1974e). The use of the new resin resulted in less 238Pu contamination in the final 237

Np product.

To establish Pu:Np ratios and the plutonium isotopic composition, the ORAU Team collated the

information on plutonium contamination in the neptunium product from the Works Technical

Department reports (see the DuPont section of the References list). The Pu:Np ratios for 1968

through 1982 (excluding 1971) were analyzed on an annual basis. The plutonium isotopic 

composition data was evaluated for the entire period. The annual Pu:Np ratios were evaluated to

determine the 5th percentile of the ratio (favorable to claimants as is use of a 95th-percentile intake 

rate) and converted from a mass ratio to an activity ratio using the isotopic composition of the

plutonium mixture and the isotopic specific activities.

For each year, random values were drawn from the fitted monthly truncated normal distributions

(proportionately to the estimated sample size in each month) to create an annual distribution. The

empirical 5th percentiles of the annual distributions of the ratios were used in subsequent analyses

(see Figures 8-13 and 8-14). The calculated Pu:Np ratio for 1982 was used for all years after 1982.

The coworker study plutonium intake rates (ORAUT 2013d) were divided by the Pu:Np ratios to

determine neptunium intake rates for the period from 1968 through 1990 (see Figure 8-15). There

are two plutonium intake rates in the coworker study, one each for types M and S. The

corresponding neptunium intake rates for each solubility type are shown, although neptunium itself is

only evaluated as a type M material. For comparison, the coworker study intake rates are also

shown. During the 1970 to 1990 period when WBC data were used, intake rates based on

interpolation of the urinalysis- based coworker intake rates before and after this period are also

presented for comparison. The 1980 to 1984 period has more neptunium urinalysis data available

than any other portion of the 1970s or 1980s. A neptunium intake rate was calculated in

accordance with the normal internal coworker study methodology (ORAUT 2013d, ORAUT 2014). 

That intake rate is also shown in Figure 8-15 and falls directly along the interpolation line of the

neptunium urinalysis-based coworker study intake rates.. Urinalyses data available for 1970, 1972,

1973, 1974, 1985, and 1988 was insufficient to permit calculation of intake rates with sufficient

confidence in the calculated excretion rate. The measured excretion rates from these years were

included for comparison purposes only. Figure 8-16 shows a plot of these values along with the

predicted excretion rates from all the neptunium urinalysis-based intake rates and the individual data

points used to calculate these intake rates. The coworker study intake rate for 1968 to 1969 was

extrapolated through 1979, and the 1980 to 1984 intake rate calculated above was extrapolated 

through 1989 to generate the predicted excretion rates. As can be seen, the excretion rates are 

generally consistent.

The use of neptunium in ratio to plutonium reported in plutonium bioassay results in calculated intake 

rates substantially lower than the intake rates before and after that time period which are based on 

actual neptunium urinalysis data. 

WBC data was selected as the source data for the coworker model as detailed in ORAUT-RPRT-0056, 

A Comparison of Neptunium Coworker Models at the SRS (ORAUT 2012). The ORAU Team has 

confirmed that workers in neptunium processing areas were required to have WBCs. Neptunium 

doses calculated using in vivo data are favorable to claimants but not so unreasonably high as to be 

deemed insufficiently accurate. While WBC data was selected as the source of neptunium coworker 

intake distributions, another reasonable approach – and one directly based on neptunium bioassay 

data – would be to extend the 1968 to 1969 intake rate through 1979, use the calculated 1980 to 1984 
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 36 of 67

 

Figure 8-13. Pu:Np mass ratios. 

Figure 8-14. Pu:Np activity ratios.
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Figure 8-15. Neptunium intake rates. 

Figure 8-16. Neptunium excretion rates. 
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 38 of 67

 

neptunium intake rate for that period, then extend the 1980 to 1984 intake rate through 1990. This 

approach would provide an approximation of the interpolation line that is favorable to claimants, is 

consistent with gradual improvement in contamination control and worker safety and dose limitation, 

and is more favorable to claimants in comparison with using intakes based on the Pu:Np ratios.

The ORAU Team analyzed the neptunium coworker data from 1961 through 1989 to determine if

there was a statistical difference in stratum from construction trade workers (CTWs) versus nonCTWs. The analysis revealed that the CTW strata did not differ from the strata for all monitored

workers between 1961 and 1989 (ORAUT 2012). Final stratified neptunium coworker statistics will

be generated using time-weighted one-person, one-sample (TWOPOS) calculation methods

documented in ORAUT-RPRT-0053, Analysis of Stratified Coworker Datasets (ORAUT 2014), and

Draft Criteria for the Evaluation and Use of Coworker Datasets (Neton 2015).ln summary, doses from

neptunium can be bounded using bioassay available for the claimant and from coworker distributions

generated for CTWs and non-CTWs using WBC results for 1971 through 1990 and sufficient

neptunium urinalysis results for 1991 through 1995.

8.4 INCIDENTS

Some incidents involving work with radioactive materials were categorized for official review and 

tracked in the Special Hazard Incidents (SHI) reports available through 1989 (DuPont 1954–1959, 

1962–1974, 1974–1984, 1983–1989). Reports of these incidents were retained in SRS Dosimetry SHI 

files. In addition to SHIs, SRS investigated incidents resulting from any of the following, as required by 

DPSOP-40, Special Hazards Bulletin 2 (DuPont 1972b, p. 183):

• Acts or conditions that caused or could have caused radiation or contamination hazards;

• Incidents of contamination that required costly clean-up or that concerned the Health Physics 

group,

• Incidents that caused internal body contamination or that concerned the Health Physics or 

Medical groups, and 

• Incidents exceeding criticality control limits given in Technical Standards, Operating 

Procedures, or Test Authorizations.

Bulletin 2 required investigations to be conducted (1) to determine pertinent facts and conditions about 

unsafe practices or unusual incidents involving radiation or contamination and (2) to recommend 

measures to prevent to prevent recurrence. The bulletin required any individual who was aware of a 

circumstance like one of those listed to promptly report it to supervision or Health Physics supervision.

Selected incidents occurring when neptunium was processed are listed in Attachment A, Table A-2. 

While none of the incidents involved the use of neptunium, they help demonstrate management and 

Health Physics support and monitoring of locations where neptunium tasks were performed. 

The numbers of incidents recorded by location where neptunium was processed or handled, 

regardless of incident type, are presented in Table 8-5. Several of the incidents recorded for M-Area 

(Buildings 305-M and 321-M) involved storage and criticality issues. No incidents of the level requiring 

inclusion in the SRS dosimetry SHI files involved the use of neptunium.
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Table 8-5. Special hazard incidents by location. 

Location 1960s 1970s 1980s

Building 305-M 2 2 0

Building 321-M 3 10 10

Building 773-A 14 13 5

Building 235-F 1 0 2

Building 772-F 5 3 12

HB Line 1 3 6

F-Canyon 10 2 5

H-Canyon 8 5 6

The ORAU Team examined a sampling of records in the NIOSH-Division of Compensation Analysis 

and Support Claims Tracking System (NOCTS) for SRS workers to determine if personal incident 

records were available where workers received contamination in areas where neptunium was 

processed.

• April 1966: A technician working in C-155, Building 773-A was not properly wearing rubber 

gloves while working in a glovebox, resulting in personal contamination. The worker’s hand 

was contaminated, but nasal smears were negative (NOCTS).

• June 1967: Air activity increased to 2 × 10-12 μCi/cm3 237Np while a worker was changing 

glovebox cabinet glove ports in Room 160, Building 235-F. Personnel were wearing assault 

mask (NOCTS). One Separations Operator received neptunium intake (ORAUT 2008).

• March 1968: A glove ruptured during slug line work in Room 107A, Building 235-F (NOCTS). 

One Separations Operator received a neptunium intake (ORAUT 2008).

• April 1968: A Separations Operator was contaminated when a process cabinet glove failed in 

Room 107A, Building 235-F. The operator’s coveralls were contaminated. Bioassay did not 

detect an intake of radioactivity (NOCTS).

• June 1968: A Separations Operator was contaminated when a process cabinet glove failed in 

Room 107A, Building 235-F (NOCTS). Bioassay indicated operator received an intake of 

237Np (ORAUT 2008).

• July 1968: A Separations Operator received a puncture wound on the left ring finger during 

cabinet glove work in Room 107A, Building 235-F. The wound monitor showed either 

621 dpm 238Pu or 42 dpm 237Np. The wound was excised by the plant doctor and no intake 

was detected (NOCTS).

• February 1970: A Separations Operator without respiratory protection erected a containment 

hut over an area already contaminated in HB Line (NOCTS). The worker received an 

inhalation intake of 237Np (ORAUT 2008).

• August 1971: A technician working in L-136, Building 772-F was contaminated while handling 

contaminated equipment. Bioassay revealed an intake of 238Pu (NOCTS; ORAUT 2008).

• January 1972: One construction worker continued installation of Pu-Np partitioning equipment 

in the JT·3 process cabinet in Room 311. Transferable contamination was measured up to 

108 dpm/ft2

. Gamma radiation exposure rates up to 100 mR/hr were measured in the cabinet. 

Plastic suits were worn for personnel protection and containment huts were used for 

contamination control. Even with these precautions, as one employee undressed after work 

he contaminated his hair to 80,000 dpm and his right cheek to 30,000 dpm. A second 
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employee contaminated his coveralls to 40,000 dpm when a seam in his plastic suit failed. 

Bioassay analyses indicated that neither employee assimilated radioactive materials 

(DuPont 1972f).

• December 1972: A Separations Operator received a puncture wound while attempting to 

remove a prefilter from the filter housing in the H & V Room, Building 235-F (NOCTS). The 

worker received a 237Np intake via the wound.

• July 1973: A Separations Operator was contaminated while welding and decontamination of 

uranium and neptunium billets in Room 107D, Building 235-F (NOCTS). Follow-up bioassay 

indicated the worker received an intake of 237Np (ORAUT 2008).

• November 1974: While working in the Neptunium Compact Operating Room, two 

Maintenance Mechanics and a Separations Operator received nasal contamination (to 

420 dpm, 25 dpm, and 30 dpm, respectively) due to a process cabinet glove failure. The 

Maintenance Mechanic with the highest nasal contamination also had contamination to 

10,000 dpm on his wrist. There were five other persons in the room at the time; their nasal 

smears were negative. Bioassay sampling for the three persons with positive nasal smears 

was initiated. A survey of the room identified 1 failed glove and 14 contaminated gloves. The 

failed glove was contaminated to 8 × 106 dpm alpha; the other 14 gloves were contaminated 

with levels to 1 × 105 dpm. The floor was contaminated up to 10,000 dpm/ft2 (DuPont 1974h).

• August 1975: A maintenance worker was contaminated with plutonium in L-130, Building 

772-F. Contamination was measured on the worker’s glove. Bioassay for internal intakes was 

negative (NOCTS).

• November 1978: An airborne release occurred in Building 235-F, room not given. No intakes 

were detected by bioassay (NOCTS).

• July 1979: A maintenance worker’s right forearm was contaminated to 20,000 dpm alpha after 

a glove failed in Cell 2 in the east maintenance room, Building 235-F. Nasal smears for intake 

of radioactivity were negative (NOCTS).

• June 1980: After completion of neptunium billet outgassing, transferable contamination to 

3 × 106 dpm alpha/1,000 cm2 was detected on the hood, furnace floor, valves, and manifold 

fittings. No particulate airborne radioactivity was detected in the work area. Employees wore 

appropriate respiratory protection. All equipment was decontaminated to less than 500 dpm 

alpha/1,000 cm2 (DuPont 1980f).

• November 1979: The cladding on an extruded neptunium tube cracked in 321-M. Alpha 

contamination to 2.0 × 105 dpm was detected. No transferable or airborne contamination was 

detected. Radiation exposure rates to 200 mR/hr were measured 45 cm from the tube

(DuPont 1979d).

• July 1981: A technician was contaminated after spilling a sample of plutonium in L-127, 

Building 772-F. Bioassay revealed an inhalation intake of 238Pu (ORAUT 2008; NOCTS).

• October 1981: A maintenance worker’s left wrist was contaminated to 40,000 dpm alpha after 

tape came from glove in the east maintenance room, Building 235-F. Nasal smears for intake 

of radioactivity were negative (NOCTS).

• March 1982: A technician working in L-147, Building 772-F was exposed to high airborne 

radioactivity. Bioassay revealed intakes of 238Pu, 239Pu, and 241Pu (NOCTS).
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• April 1982: A technician working in L-126, Building 772-A was contaminated. Bioassay 

detected an intake of 238Pu (ORAUT 2008; NOCTS).

• July 1983: A construction worker was contaminated while drilling through a wall in High-Level 

Cell 16, Building 773-A. Bioassay for intakes was negative (NOCTS).

• January 1984: A technician working in B-142-146, Building 773-A was contaminated after a 

glovebox glove ruptured. Contamination was detected on the worker’s laboratory coat, pants, 

and hands. Bioassay indicated an intake of 244Cm (ORAUT 2008; NOCTS).

• February 1988: A maintenance worker was exposed to airborne plutonium in Building 235-F 

when exhaust fans stopped. Follow-up bioassay did not detect an intake of radioactivity 

(NOCTS).

• June 1988: A technician working in L-123, Building 772-F was contaminated while mixing a 

solution as the top came off. Bioassay revealed the worker sustained an intake of 238Pu 

(ORAUT 2008; NOCTS).

• February 1989: A maintenance worker was exposed to airborne plutonium in Building 235-F 

when exhaust fans stopped. Follow-up bioassay did not detect an intake of radioactivity 

(NOCTS).

• April 1989: A carpenter was briefly exposed to 238Pu and 237Np in Room 307 of the old HB 

Line when the fresh air suit failed momentarily. The worker took off the suit top and shell 

before he could be stopped. Health Physics quickly intervened putting on a new suit. The 

worker was placed on fecal and in vivo bioassay, which noted intakes of both 238Pu and 237Np

(ORAUT 2008; NOCTS).

• August 1989: An operator was exposed to high airborne activity in the old HB Line. Bioassay 

did not detect an intake of radioactivity (NOCTS).

• April 1990: A construction worker was contaminated while trying to break through the floor in 

L-143, Building 772F. Bioassay for internal intakes was negative (NOCTS).

• August 1991: Workers were erecting a contamination hut when a plug fell out of the cabinet 

exhaust duct in Building 235-F neptunium billet maintenance. Bioassay confirmed that one of 

the workers received intakes of 238Pu and 237Np (NOCTS).

• March 1992: A Separations Operator was exposed to airborne plutonium when an airflow 

reversal occurred in Room 308, old HB Line. Bioassay did not detect an intake of radioactivity 

(NOCTS).

• September 1992: An operator received 20,000 dpm alpha-beta contamination on his shoe 

cover in the old HB Line. Bioassay did not detect an intake of radioactivity (NOCTS).

Contamination incidents did occur in neptunium processing areas, some with worker intakes of 

neptunium or plutonium. However, the available evidence shows that such incidents were monitored 

by Health Physics with follow-up surveys and bioassay when appropriate. 

9.0 CONCLUSION

In this report, the ORAU Team details primary and ancillary processes SRS used to separate 

neptunium from process flows into a nitrate, purify the nitrate product to neptunium oxide, and fabricate 
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 42 of 67

 

NpO2 into reactor-ready components. Using the available records, the ORAU Team demonstrates that 

Health Physics provided workplace monitoring of all areas where primary and ancillary work tasks 

were performed, using data from neptunium and other processes. The preponderance of 

documentation demonstrates that work with neptunium was designed and planned to prevent or 

reduce exposures to radiation but that when such exposures occurred health Physics was there to 

monitor and remediate contamination events. Routine air concentrations were effectively controlled to 

5% RCG for neptunium, or less than 2 × 10-13 μCi/cm3

. When off-normal occurrences occurred SRS 

took appropriate action with follow-up bioassay. Access to areas where neptunium work was 

conducted was controlled and required Health Physics approval before entry. In the report, the ORAU 

Team shows there were no incidents with 237Np significant enough to be included in the SRS 

Dosimetry Special Hazards Investigations files.

SRS has routinely monitored neptunium workers for radiation exposure. Potential intakes and internal 

doses of 237Np to neptunium workers, those that would have been exposed to neptunium in F- and 

H-Canyons, HB Line, 235-F, 321-M, 772-F, 773-A, and ancillary locations, can be reconstructed using 

actual worker data and coworker intakes when monitoring data is missing. Final sets of stratified 

coworker intakes will be derived using neptunium urinalysis through 1969 and 1990 through 1995, and 

WBC data through 1989 using TWOPOS calculation methods (ORAUT 2014; Neton 2015). ORAUTOTIB-0081, Internal Coworker Dosimetry Data for the Savannah River Site (ORAUT 2013d), will be 

revised once the final stratified coworker models are generated.
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 43 of 67

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DOE (U.S. Department of Energy, 1991, Report of an Investigation into Deterioration of the Plutonium 

Fuel Form Fabrication Facility (PuFF) at the DOE Savannah River Site, DOE/NS-0002P, 

Office of Nuclear Safety, Washington, D.C., October. [SRDB Ref ID: 120782]

DOE (U.S. Department of Energy), 1992, U.S. Department of Energy Radiological Control Manual, 

DOE/EH-0256T, DOE N 5480.6, Office of Assistant Secretary for Environment, Safety and 

Health, Washington, D.C., June. [SRDB Ref ID: 11515]
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 45 of 67

DOE (U.S. Department of Energy), 1994, U.S. Department of Energy Radiological Control Manual, 

DOE/EH-0256T, Rev. 01, Office of Assistant Secretary for Environment, Safety and Health, 

Washington, D.C., April. [SRDB Ref ID: 14856]

Driggers, F. E., and D. S. St. John, 1957, “Production of Np-237,” memorandum to G. Dessauer, E. I. 

du Pont de Nemours and Company, Savannah River Plant, Aiken, South Carolina, March 14. 

[SRDB Ref ID: 99366]

Duffey, J., 2003a, Characterization of Neptunium Oxide Generated Using the HB-Line Phase II 

Flowsheet, WSRC-TR-2003-00388, Rev. 0, Westinghouse Savannah River Company, 

Savannah River Site, Aiken, South Carolina, August. [SRDB Ref ID: 124005]

Duffey, J., 2003b, Gas Generation Testing of Neptunium Oxide Generated Using the HB-Line Phase 

II Flowsheet, WSRC-TR-2003-00389, Rev. 0, Westinghouse Savannah River Company, 

Savannah River Site, Aiken, South Carolina, August. [SRDB Ref ID: 124006]

Duffey, J., 2003c, Lab Scale Production of NpO2, WSRC-TR-2003-00392, Rev. 0, Westinghouse 

Savannah River Company, Savannah River Site, Aiken, South Carolina, August 27. [SRDB 

Ref ID: 124007]

DuPont (E. I. du Pont de Nemours and Company), 1954–1959, Dosimetry Special Hazards Incident 

Investigations, Reports 001–099, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 45086]

DuPont (E. I. du Pont de Nemours and Company), 1957a, Monthly Progress Report, June 1957, 

Works Technical Department, DPSP 57-1-6, Savannah River Plant, Aiken, South Carolina, 

July 18. [SRDB Ref ID: 11599]

DuPont (E. I. du Pont de Nemours and Company), 1957b, Monthly Progress Report, April 1957, 

Technical Division, DPST-59-1-4, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 103452]

DuPont (E. I. du Pont de Nemours and Company), 1957c, Monthly Progress Report, July 1957, Works 

Technical Department, DPSP 57-1-7, Savannah River Plant, Aiken, South Carolina, August 

19. [SRDB Ref ID: 11601]

DuPont (E. I. du Pont de Nemours and Company), 1958a, Monthly Progress Report, Technical 

Division, July 1958, DPSP 58-1-7, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 103500]

DuPont (E. I. du Pont de Nemours and Company), 1958b, Monthly Progress Report, August 1958, 

Works Technical Department, DPSP 58-1-8, Savannah River Plant, Aiken, South Carolina, 

September 19. [SRDB Ref ID: 11607]

DuPont (E. I. du Pont de Nemours and Company), 1959a, Monthly Progress Report, Technical 

Division, August 1959, DPSP 59-1-8, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 103711]

DuPont (E. I. du Pont de Nemours and Company), 1959b, Progress Report, June 1959, Works

Technical Department, DPSP 59-1-6, Savannah River Plant, Aiken, South Carolina, July 21. 

[SRDB Ref ID: 11628]
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DuPont (E. I. du Pont de Nemours and Company), 1960a, Progress Report, June 1960, Works

Technical Department, DPSP 60-1-6, Savannah River Plant, Aiken, South Carolina, July 20. 

[SRDB Ref ID: 11723]

DuPont (E. I. du Pont de Nemours and Company), 1960b, Progress Report, May 1960, Works 

Technical Department, DPSP 60-1-5, Savannah River Plant, Aiken, South Carolina, June 20. 

[SRDB Ref ID: 11721]

DuPont (E. I. du Pont de Nemours and Company), 1960c, Progress Report, July 1960, Works 

Technical Department, DPSP 60-1-7, Savannah River Plant, Aiken, South Carolina, August 

17. [SRDB Ref ID: 11727]

DuPont (E. I. du Pont de Nemours and Company), 1960d, Progress Report, June 1960, Works 

Technical Department, DPSP 60-1-6, Savannah River Plant, Aiken, South Carolina, July 20. 

[SRDB Ref ID: 86251]

DuPont (E. I. du Pont de Nemours and Company), 1961–1969, Special Product Log Records 

February 16, 1961 – October 13, 1969, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 51953]

DuPont (E. I. du Pont de Nemours and Company), 1961a, Progress Report, October 1961, Works

Technical Department, DPSP 61-1-10, Savannah River Plant, Aiken, South Carolina, 

November 20. [SRDB Ref ID: 11796]

DuPont (E. I. du Pont de Nemours and Company), 1961b, Progress Report, January 1961, Works

Technical Department, DPSP 61-1-1, Savannah River Plant, Aiken, South Carolina, 

February 16. [SRDB Ref ID: 11794]

DuPont (E. I. du Pont de Nemours and Company), 1961c, Progress Report, June 1961, Works

Technical Department, DPSP 61-1-6, Savannah River Plant, Aiken, South Carolina, July 24. 

[SRDB Ref ID: 68253]

DuPont (E. I. du Pont de Nemours and Company), 1961d, Monthly Progress Report, Technical 

Division, May 1961, DPSP 61-1-5, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 105063]

DuPont (E. I. du Pont de Nemours and Company), 1961e, Monthly Progress Report, June 1961, 

Technical Division, DPST-61-1-6, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 104946]

DuPont (E. I. du Pont de Nemours and Company), 1961f, Monthly Progress Report, July 1961, 

Technical Division, DPST-61-1-7, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 104950]

DuPont (E. I. du Pont de Nemours and Company), 1961h, Operating Procedure for Radiation and 

Contamination Control, DPSOP-40-HIST-Vol-1, Savannah River Plant, Aiken South Carolina, 

July. [SRDB Ref ID: 52806]

DuPont (E. I. du Pont de Nemours and Company), 1962, Progress Report, May 1962, Works 

Technical Department, DPSP 62-1-15, Savannah River Plant, Aiken, South Carolina, June 21. 

[SRDB Ref ID: 11862]
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DuPont (E. I. du Pont de Nemours and Company), 1962–1974, Dosimetry Special Hazards Incident 

Investigations, Reports 200–299, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 45094]

DuPont (E. I. du Pont de Nemours and Company), 1963a, Progress Report, February 1963, Works

Technical Department, DPSP 63-1-2, Savannah River Plant, Aiken, South Carolina, March 22. 

[SRDB Ref ID: 11868]

DuPont (E. I. du Pont de Nemours and Company), 1963b, Progress Report, September 1963, Works 

Technical Department, DPSP 63-1-9, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 68452]

DuPont (E. I. du Pont de Nemours and Company), 1964, Progress Report, December 1964, Works 

Technical Department, DPSP 64-1-12, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 68108]

DuPont (E. I. du Pont de Nemours and Company), 1965a, Progress Report, May 1965, Works

Technical Department, DPSP 65-1-5, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 68105]

DuPont (E. I. du Pont de Nemours and Company), 1965b, Savannah River Laboratory Monthly 

Report, July 1965, DPSP 65-1-7, Aiken, South Carolina. [SRDB Ref ID: 106741]

DuPont (E. I. du Pont de Nemours and Company), 1965c, Savannah River Laboratory, Monthly 

Report, January 1965, DP-65-1-1, Aiken, South Carolina. [SRDB Ref ID: 106713]

DuPont (E. I. du Pont de Nemours and Company), 1965d, Progress Report, November 1965, Works 

Technical Department, DPSP 65-1-11, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 68363]

DuPont (E. I. du Pont de Nemours and Company), 1966–1967, Building 235-F Air Samples November 

1966 - June 1967, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 129615]

DuPont (E. I. du Pont de Nemours and Company), 1966a, Progress Report, June 1966, Works

Technical Department, DPSP 66-1-6, Savannah River Plant, Aiken, South Carolina, July 21. 

[SRDB Ref ID: 68107]

DuPont (E. I. du Pont de Nemours and Company), 1966b, Progress Report, March 1966, Works

Technical Department, DPSP 66-1-3, Savannah River Plant, Aiken, South Carolina, April 20. 

[SRDB Ref ID: 68109]

DuPont (E. I. du Pont de Nemours and Company), 1967a, Progress Report, August 1967, Works

Technical Department, DPSP 67-1-8, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 68237]

DuPont (E. I. du Pont de Nemours and Company), 1967b, Progress Report, March 1967, Works 

Technical Department, DPSP 67-1-3, Savannah River Plant, Aiken, South Carolina, April 20. 

[SRDB Ref ID: 12455]

DuPont (E. I. du Pont de Nemours and Company), 1967c, Works Technical Department, Report for 

October 1967, DPSP 67-1-10, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68067]
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DuPont (E. I. du Pont de Nemours and Company), 1967d, Works Technical Department, Report for 

November 1967, DPSP 67-1-11, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68069]

DuPont (E. I. du Pont de Nemours and Company), 1968a, Works Technical Department, Report for 

June 1968, DPSP 68-1-6, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68300]

DuPont (E. I. du Pont de Nemours and Company), 1968b, Works Technical Department, Report for 

January 1968, DPSP 68-1-1, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68292]

DuPont (E. I. du Pont de Nemours and Company), 1968c, Works Technical Department, Report for 

July 1968, DPSP 68-1-7, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68302]

DuPont (E. I. du Pont de Nemours and Company), 1968d, Works Technical Department, Report for 

August 1968, DPSP 68-1-8, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68304]

DuPont (E. I. du Pont de Nemours and Company), 1968e, Monthly Progress Report, January 1968, 

Technical Division, DPST-68-1-1, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 106672]

DuPont (E. I. du Pont de Nemours and Company), 1969a, Works Technical Department, Report for 

June 1969, DPSP 69-1-6, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68185]

DuPont (E. I. du Pont de Nemours and Company), 1969b, Works Technical Department, Report for 

July 1969, DPSP 69-1-7, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68471]

DuPont (E. I. du Pont de Nemours and Company), 1969c, Works Technical Department, Report for 

August 1969, DPSP 69-1-8, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72814]

DuPont (E. I. du Pont de Nemours and Company), 1969d, Works Technical Department, Report for 

February 1969, DPSP 69-1-2, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68189]

DuPont (E. I. du Pont de Nemours and Company), 1969e, Savannah River Laboratory Monthly 

Report, February 1969, DPSP 69-1-2, Aiken, South Carolina. [SRDB Ref ID: 106871]

DuPont (E. I. du Pont de Nemours and Company), 1969f, Works Technical Department, Report for 

February 1969, DPSP 69-1-2, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68327]

DuPont (E. I. du Pont de Nemours and Company), 1969g, Pu & No Record Book, Savannah River 

Plant, Aiken, South Carolina, April 8. [SRDB Ref ID: 51973]

DuPont (E. I. du Pont de Nemours and Company), 1969h, Works Technical Department, Report for 

April 1969, DPSP 69-1-4, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68182]
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DuPont (E. I. du Pont de Nemours and Company), 1970a, Works Technical Department, Report for 

July 1970, DPSP 70-1-7, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72819]

DuPont (E. I. du Pont de Nemours and Company), 1970b, Savannah River Laboratory Monthly 

Report, October 1970, DPSP 70-1-10, Aiken, South Carolina. [SRDB Ref ID: 106859]

DuPont (E. I. du Pont de Nemours and Company), 1970c, Works Technical Department, Report for 

September 1970, DPSP 70-1-9, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68002]

DuPont (E. I. du Pont de Nemours and Company), 1970d, Works Technical Department, Report for 

October 1970, DPSP 70-1-10, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68011]

DuPont (E. I. du Pont de Nemours and Company), 1971–1974, Savannah River Plant Radiation & 

Contamination Control, DPSOP-40-Hist-Vol-3, Savannah River Plant, Aiken, South Carolina. 

[SRDB Ref ID: 86138]

DuPont (E. I. du Pont de Nemours and Company), 1971a, Works Technical Department, Report for 

April 1971, DPSP 71-1-4, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68024]

DuPont (E. I. du Pont de Nemours and Company), 1971b, Savannah River Laboratory Monthly 

Report, Technical Division, March 1971, DPSP 71-1-3, Aiken, South Carolina. [SRDB Ref ID: 

106699]

DuPont (E. I. du Pont de Nemours and Company), 1971c, Works Technical Department, Report for 

October 1971, DPSP 71-1-10, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68022]

DuPont (E. I. du Pont de Nemours and Company), 1971d, Bioassay Control, DPSOL 193-302, Rev. 5, 

Aiken, South Carolina, September 1. [SRDB Ref ID: 124941]

DuPont (E. I. du Pont de Nemours and Company), 1971e, Works Technical Department, Report for 

May 1971, DPSP 71-1-5, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68026]

DuPont (E. I. du Pont de Nemours and Company), 1971f, Works Technical Department, Report for 

December 1971, DPSP 71-1-12, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68264]

DuPont (E. I. du Pont de Nemours and Company), 1972a, Savannah River Laboratory, Monthly 

Report, June 1972, DP-72-1-6, Aiken, South Carolina. [SRDB Ref ID: 86010]

DuPont (E. I. du Pont de Nemours and Company), 1972b, Radiation and Contamination Control, 

DPSOP-40-Hist-Vol-2, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 52805]

DuPont (E. I. du Pont de Nemours and Company), 1972c, Savannah River Laboratory, Monthly 

Report, April 1972, DP-72-1-4, Aiken, South Carolina. [SRDB Ref ID: 86041]

DuPont (E. I. du Pont de Nemours and Company), 1972d, collection of Radiation Multisurvey 

Logsheets, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 70086]
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 50 of 67

DuPont (E. I. du Pont de Nemours and Company), 1972e, collection of Radiation Multisurvey 

Logsheets, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 70086]

DuPont (E. I. du Pont de Nemours and Company), 1972f, Works Technical Department, Report for 

January 1972, DPSP 72-1-1, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68265]

DuPont (E. I. du Pont de Nemours and Company), 1973–1974, collection of air sampling results, 

Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 114648]

DuPont (E. I. du Pont de Nemours and Company), 1973, Works Technical Department, Report for 

December 1977, DPSP 73-1-12, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68050]

DuPont (E. I. du Pont de Nemours and Company), 1974–1984, Dosimetry Special Hazards Incident 

Investigations, Reports 300–399, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 45096]

DuPont (E. I. du Pont de Nemours and Company), 1974a, Works Technical Department, Report for 

January 1974, DPSP 74-1-1, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72893]

DuPont (E. I. du Pont de Nemours and Company), 1974b, Works Technical Department, Report for 

February 1974, DPSP 74-1-2, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72894]

DuPont (E. I. du Pont de Nemours and Company), 1974c, Works Technical Department, Report for 

March 1974, DPSP 74-1-3, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72895]

DuPont (E. I. du Pont de Nemours and Company), 1974d, Works Technical Department, Report for 

April 1974, DPSP 74-1-4, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72896]

DuPont (E. I. du Pont de Nemours and Company), 1974e, Works Technical Department, Report for 

May 1974, DPSP 74-1-5, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72897]

DuPont (E. I. du Pont de Nemours and Company), 1974f, Works Technical Department, Report for 

July 1974, DPSP 74-1-7, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72898]

DuPont (E. I. du Pont de Nemours and Company), 1974g, Savannah River Laboratory, Monthly 

Report, June 1974, DP-74-1-6, Aiken, South Carolina. [SRDB Ref ID: 86049]

DuPont (E. I. du Pont de Nemours and Company), 1974h, Works Technical Department, Report for 

November 1974, DPSP 74-1-11, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68041]

DuPont (E. I. du Pont de Nemours and Company), 1974i, Works Technical Department, Report for 

September 1974, DPSP 74-1-9, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68041]
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DuPont (E. I. du Pont de Nemours and Company), ca. 1975a, photograph of workers on the 

neptunium billet line, Building 235-F, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 153958]

DuPont (E. I. du Pont de Nemours and Company), ca. 1975b, photograph of maintenance side of the 

neptunium billet line, Building 235-F, Savannah River Plant, Aiken, South Carolina. [SRDB 

Ref ID: 153957]

DuPont (E. I. du Pont de Nemours and Company), 1975a, Works Technical Department, Report for 

August 1975, DPSP 75-1-8, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72904]

DuPont (E. I. du Pont de Nemours and Company), 1975b, Works Technical Department, Report for 

January 1975, DPSP 75-1-1, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68042]

DuPont (E. I. du Pont de Nemours and Company), 1975c, Works Technical Department, Report for 

November 1975, DPSP 75-1-11, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72906]

DuPont (E. I. du Pont de Nemours and Company), 1976a, Works Technical Department, Report for 

March 1976, DPSP 76-1-3, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72909]

DuPont (E. I. du Pont de Nemours and Company), 1976b, Works Technical Department, Report for 

June 1976, DPSP 76-1-6, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72910]

DuPont (E. I. du Pont de Nemours and Company), 1976c, Works Technical Department, Report for 

August 1976, DPSP 76-1-8, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72912]

DuPont (E. I. du Pont de Nemours and Company), 1977a, Works Technical Department, Report for 

May 1977, DPSP 77-1-5, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72915]

DuPont (E. I. du Pont de Nemours and Company), 1977b, Works Technical Department, Report for 

June 1977, DPSP 77-1-6, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72916]

DuPont (E. I. du Pont de Nemours and Company), 1977c, Works Technical Department, Report for 

July 1977, DPSP 77-1-7, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72917]

DuPont (E. I. du Pont de Nemours and Company), 1977d, Works Technical Department, Report for 

August 1977, DPSP 77-1-8, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72918]

DuPont (E. I. du Pont de Nemours and Company), 1977e, Works Technical Department, Report for 

November 1977, DPSP 77-1-11, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72922]
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DuPont (E. I. du Pont de Nemours and Company), 1977f, Works Technical Department, Report for 

December 1977, DPSP 77-1-12, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72923]

DuPont (E. I. du Pont de Nemours and Company), 1977g, Works Technical Department, Report for 

October 1977, DPSP 77-1-10, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72920]

DuPont (E. I. du Pont de Nemours and Company), 1977h, Works Technical Department, Report for 

September 1977, DPSP 77-1-9, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72919]

DuPont (E. I. du Pont de Nemours and Company), 1977i, Works Technical Department, Report for 

April 1977, DPSP 77-1-4, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72914]

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

Physics Department, January 1978, Savannah River Plant, Aiken, South Carolina. [SRDB Ref 

ID: 108843]

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

January 1978, DPSP 78-1-1, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72924]

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

February 1978, DPSP 78-1-2, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72925]

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

March 1978, DPSP 78-1-3, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68060]

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

October 1978, DPSP 78-1-10, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68282]

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

December 1978, DPSP 78-1-12, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68284]

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

June 1978, DPSP 78-1-6, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68063]

DuPont (E. I. du Pont de Nemours and Company), 1979a, Works Technical Department, Report for 

June 1979, DPSP 79-1-6, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72926]

DuPont (E. I. du Pont de Nemours and Company), 1979b, Works Technical Department, Report for 

January 1979, DPSP 79-1-1, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68331]
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DuPont (E. I. du Pont de Nemours and Company), 1979c, Works Technical Department, Report for 

February 1979, DPSP 79-1-2, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68333]

DuPont (E. I. du Pont de Nemours and Company), 1979d, Works Technical Department, Report for 

November 1979, DPSP 79-1-11, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68347]

DuPont (E. I. du Pont de Nemours and Company), 1980a, Works Technical Department, Report for 

September 1980, DPSP 80-1-9, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72929]

DuPont (E. I. du Pont de Nemours and Company), 1980b, Works Technical Department, Report for 

April 1980, DPSP 80-1-4, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68323]

DuPont (E. I. du Pont de Nemours and Company), 1980c, Works Technical Department, Report for 

January 1980, DPSP 80-1-1, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72927]

DuPont (E. I. du Pont de Nemours and Company), 1980d, Works Technical Department, Report for 

December 1980, DPSP 80-1-12, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72931]

DuPont (E. I. du Pont de Nemours and Company), 1980e, Works Technical Department, Report for 

November 1980, DPSP 80-1-11, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72930]

DuPont (E. I. du Pont de Nemours and Company), 1980f, Works Technical Department, Report for 

June 1980, DPSP 80-1-6, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68325]

DuPont (E. I. du Pont de Nemours and Company), 1980g, Works Technical Department, Report for 

July 1980, DPSP 80-1-7, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

72928]

DuPont (E. I. du Pont de Nemours and Company), 1980h, Works Technical Department, Report for 

October 1980, DPSP 80-1-10, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68352]

DuPont (E. I. du Pont de Nemours and Company), 1980i, Works Technical Department, Report for 

August 1980, DPSP 80-1-8, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

68326]

DuPont (E. I. du Pont de Nemours and Company), 1981–1984, Building 235-F Glove Failure Records 

and Daily Control Surveys, Savannah River Plant, Aiken, South Carolina. [SRDB Ref ID: 

129630]

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Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 60 of 67

 

ATTACHMENT A 

HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS

Table A-1. Health physics monitoring of specific events. 

Date Location Event

January 1966 773-A, A-122 A 200-mg source of Np-237 used in Mossbauer studies leaked, resulting 

in transferable contamination of 10,000 dpm/cm2 on the source holder. 

The source was subsequently bagged and moved to a hood. No 

additional contamination was detected (Moyer 1966c).

March 1966 773-A, B-114 A liquid sample of Np-237 was spilled in the hood; a small amount 

splashed on an employee and the laboratory floor. The employee was 

not wearing protective clothing. An alpha survey of laboratory coat gave 

24,000 dpm. The coat was discarded to radioactive waste. The floor 

had been contaminated to 30,000 dpm/ft2 but was subsequently 

decontaminated to less than 10 dpm/cm2. Survey of the worker revealed 

no skin contamination; nasal smears were negative (DuPont 1966b).

March 1966 773-A, B-114 A worker detected 6,000 dpm on his shoe after working in the hood (later 

identified as Np-237 by gamma spectroscopy). An immediate follow-up 

survey detected transferable contamination of 6,000 dpm/100 cm2 on the 

floor by the hood. The shoe and floor were cleaned (Moyer 1966d).

July 1966 773-A, B-133 After preparing Np-237 source, an employee detected low-level

contamination on his shoes (less than 1,000 dpm). A survey indicated 

contamination of the employee’s laboratory coat and rubber gloves. The 

floor and shoes were cleaned to background and the gloves were 

discarded to waste (Moyer 1966a).

August 1966 773-A, A-122 Np-237 source used in the Mossbauer studies leaked resulting in 

contamination of the source holder (60,000 dpm), laboratory floor 

(24,000 dpm), and personal shoes (2,000 dpm). The contaminated 

items were decontaminated. Nasal smears showed no intakes (Moyer 

1966b).

September 1966 773-A, B-114 An employee working with Np-237 contaminated his hands, shoes, and 

personal clothing, and spread contamination to the laboratory floor, 

personnel corridor, and his office (B-109). The worker’s hands were 

contaminated to 6,000 dpm but cleaned to background. The worker’s 

rubber gloves were contaminated to 9E+05 dpm and were discarded to 

waste. All work surfaces and equipment were decontaminated to 

background levels (Moyer 1966e).

September 1966 773-A, B-065 An alpha count rate meter and a permanent air sampler were installed 

when about 500 mg of Np-237 was introduced into a glovebox (Moyer 

1966e).

October 1967 235-F Radioactive material trapped between retaining rings was released 

during replacement of a lathe cabinet glove. Floor contamination ranged 

up to 4E+06 dpm/ft2. An operator and a Health Physics inspector both 

had contamination in their hair (20,000 dpm and 500 dpm, respectively), 

but were decontaminated. Respiratory equipment was worn. Airborne 

radioactivity was 9E-12 Ci/cm3. Special bioassay samples were 

collected (DuPont 1967b).

November 1967 235-F Separations Operators processing Np-237 received exposures above 

prorated guide values throughout 1967 that necessitated movement of 

personnel to other facilities before the end of the year. Forecasts of 

increased production prompted a thorough study of radiation problems 

and methods of reducing exposure. Options considered were better 

coordination of process steps and additional shielding (DuPont 1967c).

January 1968 777-M Contamination was detected in the Nuclear Physics laboratory after a 

sealed Np-237 source was removed from the thermal column of the SP 

reactor. Three graphite plugs were contaminated and were sent to burial 

ground. The column was decontaminated (Moyer 1968a).
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 61 of 67

ATTACHMENT A

HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS (continued)

Date Location Event

May 1968 235-F Four Np-237 foils reading 1,000 mR/hr at 3 in. were transferred from a 

shipping container to the vault (Copley and Moyer 1968a).

July 1968 HB Line Neptunium nitrate, produced at Hanford, was mixed with SRS-produced 

Np-237 nitrate for processing. The Hanford material was apparently 

contaminated with Th-234 and its progeny, which increased exposure 

rates from about 20 to 150 mR/hr when the mixture was removed from 

the line as an oxide (DuPont 1968c).

August 1968 321-M Forty Np-Al tubes were fabricated from core compacted billets. The 

measured maximum radiation dose rates for these were 1,200 mrem/hr 

gamma with 7 mrem/hr fast neutron. The maximum radiation dose 

accumulated by an individual during production of the tubes was 

110 mrem. Nine of the tubes had fixed contamination to 2,000 dpm 

alpha on the end cuts. Two of the tubes had transferable contamination 

to 100 dpm alpha (DuPont 1968d).

August 1968 P Assembly Gamma exposure does rates to 300 mrem/hr at 18-in. (3 mrem/hr fast 

neutron) were measured during the assembly of Np-Al tubes into reactor 

components (DuPont 1968d).

October 1968 773-A, B-114 A beaker containing a solution of Np-237 broke inside a hood. 

Contamination inside the hood was measured at 1.5E+06 dpm, and 

contamination measured on the floor was 3E+05 dpm/ft2. Both were 

decontaminated (Copley and Moyer 1968g).

April 1969 321-M Twenty Np-Al tubes were fabricated from core compacted billets. No 

fixed or transferable contamination was detected. The maximum 

measured dose rate was 500 mrem/hr (2 mrem/hr fast neutron) (DuPont 

1969h).

June 1969 321-M Thirty-five Np-Al tubes were fabricated from core compacted billets. One 

tube had a break in the cladding of 4 in.

2 during extrusion and was 

surveyed at 1E+06 dpm. The die on the press read 15,000 dpm 

transferable and was decontaminated. No other contamination was 

detected. The process was monitored for airborne contamination, but 

results revealed no increase during extrusion. The maximum radiation 

dose received by an individual on all billet extrusions was 200 mrem 

(Reed 1982).

August 1969 321-M Forty-eight Np-Al tubes were fabricated from core compacted billets with 

typical radiation intensities from the extruded tubes with maximum 

exposure rate 80 mrem/hr. Breaks in the cladding were observed in 

three of the tubes. The maximum contamination measured during 

surveys of these breaks was 30,000 dpm alpha transferable. Ten tubes 

were fabricated from cores of hot-press-bonded NpO2-Al slugs tubes 

with maximum exposure rate of 100 mrem/hr. Breaks were observed in 

the cladding of four of the tubes. The maximum contamination 

measured during surveys of these breaks was 45,000 dpm transferable. 

The maximum radiation dose received by an individual worker on all 

billet extrusions was 715 mrem (Reed 1982).

August 1969 773-A, D-165 Two operators who fabricated and decontaminated special neptunium 

oxide slugs had gamma exposures of 50 mR/hr. The slugs were formed 

and fabricated into billets with body exposures of 1,465 mR and 810 mR, 

respectively (Marter 1961).
Document No. ORAUT-RPRT-0065 Revision No. 00 Effective Date: 09/19/2016 Page 62 of 67

ATTACHMENT A

HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS (continued)

Date Location Event

August 1969 773-A, D-037 Machining the aluminum end caps from five neptunium oxide-Al slugs 

resulted in air activity of 125E-12 μCi/cm3 for a sampled period of thirty 

minutes. As the core material was lathed, it crumbled and contaminated 

the lathe, floor, other equipment, and the machinist. Contamination was 

highest on the lathe at 100,000 dpm/ft2. All equipment and floors were 

decontaminated to less than 25 dpm/100 cm2. Nasal swabs of the 

machinist showed some nasal contamination (400 dpm), but a follow-up 

WBC showed no measureable intake. Subsequent machining in 773-A 

was moved to a hot cell, D-049 (Moyer 1969b, 1969c).

August 1969 773-A, D-059 The exposure rate for fabricating neptunium billets ranged from 12 to 

25 mR/hr. Six workers received a total estimated body exposure of 

215 mrem. Transferable contamination to 600 dpm/ft2 was spread to the 

papered laboratory table but was cleaned (Moyer 1969c).

September 1969 773-A, D-165 The measured exposure rate for Reactor Engineering personnel to work 

with Np-Al tubes was 100 mrem/hr. Two employees accumulated a total 

estimated exposure of 150 mrem. No contamination from the work was 

measured (Hayes 1969a).

October 1969 321-M Twenty Np-Al tubes were fabricated from core compacted billets with 

typical radiation intensities from the extruded tubes with maximum 

exposure rate 200 mrem/hr. Six of the tubes had fixed alpha 

contamination with a maximum 30,000 dpm alpha on the end cuts. The 

maximum radiation dose received by an individual worker on all billet 

extrusions was 120 mrem (Reed 1982).

November 1969 773-A, B-114 An obsolete glovebox was disconnected and removed from B-114. It 

contained an estimated 5 mCi Np-237-Am-241. The glovebox was 

removed with monitoring without incident and sent for burial (Hayes 

1969b).

January 1970 321-M Thirty-seven tubes were fabricated from cores of hot-press-bonded 

NpO2-Al slugs with the maximum exposure rate 300 mrem/hr. 

Contamination was read on 10 of the tubes with a maximum 2,000 dpm 

on the end cuts (Reed 1982).

July 1970 321-M Eleven tubes were extruded from cores of hot-press-bonded NpO2-Al 

slugs with the maximum exposure rate 600 mrem/hr. The maximum 

radiation dose received by an individual on all billet extrusions was 

285 mrem (Reed 1982).

September 1970 321-M Forty-one tubes were extruded from cores of hot-press-bonded NpO2-Al 

slugs with the maximum exposure rate 360 mrem/hr (Reed 1982).

September 1970 321-M Transferable contamination to 6E+05 dpm/ft2 alpha was detected on an 

Np-Al tube and on the press die when a tube was pulled apart at the 

draw bench. Air activity was measured at 1E-12 Ci alpha/cm3

immediately following the failure. Two additional tubes had cladding 

defects with transferable contamination to 1,000 dpm. The maximum 

transferable contamination on equipment in contact with the tube was 

100 dpm/100 cm2 (DuPont 1970c).

October 1970 321-M Fixed contamination up to 1E+05 dpm was detected with cladding 

defects on two Np-Al tubes after drawing; transferable contamination 

was less than 15 dpm/100 cm2 (DuPont 1970d).

December 1970 321-M Forty-three tubes were fabricated from cores of hot-press-bonded NpO2-

Al slugs with maximum exposure rate 300 mrem/hr. Fixed contamination 

was detected at cladding defects on one tube at 4000 dpm. 

Transferable contamination was measured at less than 15 dpm/100 cm2

(Reed 1982).
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ATTACHMENT A

HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS (continued)

Date Location Event

January 1971 321-M Forty-three tubes were fabricated from cores of hot-press-bonded NpO2-

Al slugs with maximum exposure rate 300 mrem/hr. One of the tubes 

separated during the stretch-straightening process, resulting in 

transferable contamination to 1,000 dpm on the tube and 8,000 dpm/ft2

on the floor (Reed 1982; DuPont 1971a).

March 1971 321-M Ten tubes were fabricated from cores of hot-press-bonded NpO2-Al slugs 

with maximum exposure rate 300 mrem/hr (Reed 1982).

April 1971 321-M Nine tubes were fabricated from cores of hot-press-bonded NpO2-Al 

slugs with maximum exposure rate 300 mrem/hr (Reed 1982).

May 1971 321-M Twenty-seven tubes were fabricated from cores of hot-press-bonded 

NpO2-Al slugs with maximum exposure rate 700 mrem/hr (Reed 1982).

June 1971 321-M Twenty-four tubes were fabricated from cores of hot-press-bonded 

NpO2-Al slugs with maximum exposure rate 400 mrem/hr (Reed 1982).

July 1971 321-M Twenty-four Np-Al tubes were fabricated from cores of hot-press-bonded 

NpO2-Al slugs with maximum exposure rate 600 mrem/hr (Reed 1982).

December 1971 321-M Seventeen tubes were fabricated from cores of hot-press-bonded NpO2-

Al slugs with maximum exposure rate 80 mrem/hr unshielded but 

reduced to 55 mrem/hr with shielding (Reed 1982; DuPont 1971f).

January 1972 321-M Ten tubes were fabricated from cores of hot-press-bonded NpO2-Al slugs 

with maximum exposure rate 140 mrem/hr (Reed 1982).

January 1972 HB Line One construction worker was installing Pu-Np partitioning equipment in 

the JT·3 process cabinet in Room 311. Transferable contamination was 

measured up to 108 dpm/ft2 and gamma radiation exposure rates to 

100 mR/hr were measured in the cabinet. Plastic suits were worn for 

personnel protection and containment huts were used for contamination 

control. Even with these precautions, as one employee undressed 

following work, he contaminated his hair to 80,000 dpm and his right 

cheek to 30,000 dpm. A second employee contaminated his coveralls to 

40,000 dpm when a seam in his plastic suit failed. Bioassay analyses 

indicated that neither employee assimilated radioactive materials 

(DuPont 1972f).

March 1972 321-M Nine tubes were fabricated from cores of hot-press-bonded NpO2-Al 

slugs with maximum exposure rate 100 mrem/hr unshielded but reduced 

to 60 mrem/hr with shielding (Reed 1982).

May 1972 321-M Twenty tubes were fabricated from cores of hot-press-bonded NpO2-Al 

slugs with maximum exposure rate 150 mrem/hr unshielded but reduced 

to 60 mrem/hr with shielding (Reed 1982).

December 1973 322-M Two Np-237 tubes were introduced into the new glovebox facility. 

Exposure dose rates to 250 mrem/hr were detected while workers 

sawed, grinded, and polished tube sections. Workers received a total 

exposure of about 1 rem for that work. No contamination control 

problems were encountered. This work was reported as temporary, with 

the possibility of becoming routine in the future (DuPont 1973).

1974 322-M Alpha contamination up to 5E+07 dpm/ft2 was detected in the glovebox, 

Room 126, after cutting two neptunium tubes for metallurgical 

examination (DuPont 1974b).
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ATTACHMENT A

HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS (continued)

Date Location Event

November 1974 235-F Two maintenance mechanics and a Separations Operator received nasal 

contamination to 420 dpm, 25 dpm, and 30 dpm, respectively, due to a 

process cabinet glove failure while working in the Neptunium Compact 

Operating Room. The maintenance mechanic with the highest nasal 

contamination also had contamination to 10,000 dpm on his wrist. There 

were five other persons in the room at the time; their nasal smears were 

negative. Bioassay sampling for the three persons with positive nasal 

smears were initiated. A survey of the room one failed glove and 14 

contaminated gloves. The failed glove was contaminated to 8E+06 dpm 

alpha with levels to 1E+05 dpm on the other 14. The floor was 

contaminated up to 10 dpm/ft (DuPont 1974h).

1975 321-M High external exposure resulted from improper storage of neptunium 

(Ferrell 1992).

November 1975 HB Line The Health Physics office and Cold Feed Preparation Room were 

contaminated on October 3 by a process liquid spill in Process Vacuum 

Room 454. It was decontaminated and painted. Decontamination 

efforts in Room 454 and Air Lock 411 generally reduced transferable 

contamination levels from 4E+08 dpm/ft2 to 5E+04 dpm/ft2 (DuPont 

1975c).

1977 772-F A technician contaminated her upper right thigh to 2E+06 dpm and 

personal shirt to 40,000 dpm when technician dropped a process sample 

in Lab 158. Skin decontamination efforts were successful. A special 

bioassay sample was requested (DuPont 1977c).

October 1978 235-F An operator working in the neptunium line incurred nasal contamination 

of 190 dpm when a cabinet glove failed. The glove was contaminated to 

1E+04 dpm and the floor to 2E+03 dpm/0.1 m2. Room airborne activity 

remained less than the RCG during the incident. Nasal irrigation 

promptly removed the contamination. A follow-up chest count of the 

operator indicated less than the minimum detectable amount and urine 

sample results were negative (DuPont 1978f).

December 1978 321-M Eight employees collectively received an estimated 900-mrem wholebody exposure while processing 22 neptunium tubes. Exposure rates 

ranged to 300 mR/hr at 30 cm (DuPont 1978g).

January 1979 321-M Worker exposure rates ranged to 300 mR/hr at 30 cm during the 

extrusion and processing of neptunium tubes. Ten employees 

collectively received about 1,800·mrem exposure performing the work 

(DuPont 1979b). Radiation dose rates ranged up to 200 mR/hr at 30 cm 

from the tubes (DuPont 1979c).

November 1979 321-M Alpha contamination to 2E+05 dpm was detected in a 1.5-mm wide,

1.5-cm-long crack on the cladding of an extruded neptunium tube. No 

transferable or airborne contamination was detected. Gamma exposure 

rates to 200 mR/hr were measured 45 cm from the tube (DuPont 1979d).

June 1980 321-M Transferable contamination to 3E+06 dpm alpha/1,000 cm2 was detected 

on the hood furnace floor, valves, and manifold fittings after completion 

of neptunium billet outgassing. No particulate airborne radioactivity was 

detected in the work area. Employees wore appropriate respiratory 

protection. All equipment was decontaminated to less than 500 dpm 

alpha/1,000 cm2 (DuPont 198fd).
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ATTACHMENT A

HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS (continued)

Date Location Event

June 1980 772-F Contamination to 2.5E+05 dpm/100 cm2 was detected on the floor of 

L-138 following housekeeping inside a laboratory bench where 

neptunium samples were processed. Contamination ranging from 4,000 

to 20,000 dpm/100 cm2 was spread to the utility corridor and three other 

laboratory modules. Shoe covers of several technicians were 

contaminated to 20,000 dpm. No airborne activity was detected and 

nasal smears from personnel were negative. Bioassay samples were 

collected from five technicians (DuPont 1980f).

1980 325-F A nuclear incident monitor (NIM) alarm occurred in the Neptunium Line 

Maintenance Room when mechanic checked a gamma monitor adjacent 

to the NIM without bypassing the NIM as required by procedure. All 

personnel evacuated the building according to procedure and there was 

no spread of contamination (DuPont 1980a).

August 1980 321-M Exposure rates to 205 mrem/hr (5 mrem/hr fast neutron) were measured 

at 30 cm from the core section of neptunium tubes during extrusion. 

Personnel accumulated exposures were approximately 1.5 rem for the 

extrusion work (DuPont 1980i).

Table A-2. Special hazards incidents.

SHI# Date Location Description

273 Mar-73 Building 773-A 

Decontamination 

Facility:

A General Service Operator released airborne activity to the 

decontamination room environment while removing solid radioactive 

waste from the Decontamination Chamber. An Eberline alpha count 

rate meter alarmed and alerted him to the presence of alpha activity. 

He obtained assistance to remove his outer protective clothing and 

went with a Radiation Control Inspector to the Personnel 

Decontamination Room. It was found he had a high nasal smear of 

about 3.6E+04 dpm alpha. Later a whole-body count indicated a 

positive uptake of curium-244 (DuPont 1962–1974).

283 Feb-71 Building 773-A 

Room B-150

An Analytical Chemistry Division chemist assimilated some curium 

while removing samples from storage. Decontamination of the chemist 

was accomplished under the surveillance of Radiation Control. He 

was sent to Medical where an aerosol chelation·treatment was given. 

A chest count and subsequent bioassay data confirmed an uptake of 

curium less than the maximum permissible body burden (DuPont 

1962–1974).

297 Feb-74 Building 773-A 

Room B-061

A Nuclear Materials Division technician received a tritium assimilation 

of about 140 μCi/L during a physical inventory of metal specimens that 

contained absorbed tritium and that were stored in packages in a 

freezer (DuPont 1962–1974).

304 Oct-74 HB Line Plutonium contamination from a Freon cooling system spread to 

nearby rooms during maintenance work (DuPont 1974–1984).

310 Oct-75 HB Line Liquid was observed seeping under the door from Room 454 into Air

Lock 4llA at 2:00 p.m. on October 3, 1975. The solution transfer 

vacuum system was immediately shut down. Further inspection 

revealed liquid seeping through the building expansion joints and down 

the walls in Room 302 and a section of Corridor 308 (Health Physics 

Office area) Liquid also spread under transite wall panels into Air Lock 

4llA and Room 4l0S (DuPont 1974–1984).

324 Mar-77 Building 772-F 

Laboratory

A decontamination facility attendant received a confirmed Pu-238 

assimilation while disposing of excess radioactive solution samples 

(DuPont 1974–1984).
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ATTACHMENT A

HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS (continued)

SHI# Date Location Description

330 Nov-77 Building 773-A 

Rooms E-063 

and E-065

Four Laboratory Operations and Services Division employees (two 

maintenance mechanics, a laboratory technician, and a 

decontamination facility assistant) were exposed to high 

concentrations of airborne curium contamination while working in the 

Manipulator, Decontamination, and Repair Facility in the High Level 

Caves. Two separate releases of contamination occurred as a result 

of work being performed on two Manipulator Thru-Tubes from the 

Target Fabrication Facility. The four employees received nasal 

contamination and two had indications of internal assimilation (DuPont 

1974–1984).

331 Jan-78 Building 773-A 

High Level Caves

A Laboratory Operations and Services Division employee (Laboratory 

Technician Number 1) unsuspectingly released airborne curium 

contamination while taking measurements in High-Level Caves Cell 

Block A. Accompanying him into Cell Block A were three other 

employees (Laboratory Technician Number 2 and two maintenance 

mechanics). While taking smear surveys during a follow-up of the 

incident, a radiation control inspector, accompanied by the first 

technician, released further airborne curium contamination. The 

inspector and the technician received nasal contamination and internal 

assimilations. The other technician and one of the mechanics received 

skin contamination (DuPont 1974–1984).

343 Jan-80 HB Line When a cabinet exhaust high-efficiency particulate air filter was 

introduced into the HB-Line Recovery Facility (in its polyvinylchloride 

bag port bag) it was placed on the top flange of the RD-l scrap 

dissolver. The dissolver was operating at 120°C, and after 

approximately 10 min the bag caught fire. The fire was apparently 

extinguished by the cabinet Halon fire suppression system but 

reignited several minutes later. It was finally extinguished by the Halon 

system. Radioactivity releases to the process rooms were minimal, 

and there was no increase in radioactivity released to the environment 

during or after the fire. There were no injuries, personnel 

assimilations, or capital equipment damage resulting from the incident 

(DuPont 1974–1984).

344 Feb-80 Building 773-A 

Rooms B-147

A Construction Division sheet metal craftsman removing an installed 

wooden hood in Laboratory B-147 of Building 773-A noticed dust 

smeared on the surgeon's gloves he was wearing. Monitoring 

revealed the presence of contamination. The gloves were removed 

and Radiation Control was immediately summoned Radiation Control 

personnel, who effected immediate decontamination of the individual. 

Subsequent bioassay data confirmed that an assimilation of plutonium 

estimated at less than 10% of the maximum permissible body burden 

had occurred (DuPont 1974–1984).

352 Feb-81 Building 321-M 

Machining Room

A raw materials operator had a confirmed assimilation of enriched 

uranium while working in the machining room during the period 

February 3, 1981, through March 2, 1981 (DuPont 1974–1984).

358 Mar-77 Building 772-F 

Fan Room

A Power Operator received a low-level plutonium assimilation from 

airborne contamination when he started a vacuum pump in the 772-F 

fan room (DuPont 1974–1984).

362 Sep-81 Building 772-F 

Room 156-A

A Laboratories Shift Supervisor received Pu-239 skin contamination 

when inventorying emission standards in 772-F (DuPont 1974–1984).

365 Sep-81 HB Line A mechanic received a Pu-238 contaminated puncture wound from an 

aluminum electrical wire while inspecting a failed agitator in a process 

cabinet (DuPont 1974–1984).
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ATTACHMENT A

HEALTH PHYSICS MONITORING OF SPECIFIC EVENTS (continued)

SHI# Date Location Description

391 Oct-83 HB Line 

Plutonium 

Finishing, Room 

410

A mechanic received a Pu-238 assimilation during purge of level dip 

tubes in Filtrate Catch Tank EP 25 (DuPont 1974–1984).

401 Jan-84 Building 773-A 

Rooms B-142-

146

An Analytical Development Division analyst received Cm-244 skin and 

nasal contamination while preparing alpha mounts of solution samples 

submitted by the Target Fabrication Facility. The laboratory was also 

contaminated. Subsequent bioassay results confirmed a biological 

uptake by the analyst (DuPont 1983–1989).

414 Aug-84 HB Line Room 

410

A construction pipe fitter received a confirmed plutonium assimilation 

when he ran his contaminated gloved hand under his plastic suit top 

and removed his cloth hood (DuPont 1983–1989).

440 Oct-85 Building 772-F 

Laboratory L-174

A technical analyst received a confirmed plutonium assimilation while 

handling Pu-239 metal samples in preparation for impurity analyses by 

emission spectroscopy (DuPont 1983–1989).

444 Jan-86 HB Line (old) Two construction electricians, one construction electrical foreman, and 

one health protection inspector received nasal contamination while the 

two electricians were drilling a 1-in. hole through a concrete wall. One 

of the electricians received a confirmed plutonium assimilation (DuPont 

1983–1989).

470 June Building 772-F 

Laboratory L-126

A Laboratories Department analyst received total nasal contamination 

of 13,005 dpm Pu-238 while discarding Pu-239 standard solutions in a 

radiobench. The Pu-239 standards had been stored in a glovebox in 

L-126, which was contaminated with Pu-238. Bioassay results 

indicated that the analyst did not receive an uptake (DuPont 1983–

1989).

1987

485 Apr-89 HB Line (Old) 

Room 307

A Separations Operator received a puncture wound to his knee while 

inadvertently kneeling on a sharp object. Initial surveys conducted in 

H-Area resulted in no detectable contamination. Follow-up surveys the 

next day detected minor contamination of the wound site. The wound 

was then excised. The bioassay program confirmed that no 

assimilation was experienced (DuPont 1983–1989).

486 Apr-89 Building 773-A 

B-141 Office and 

B-194 Personnel 

Corridor

Personal shoes contaminated with 10,000 dpm of plutonium. No other 

activity was detected. Office and corridor were contaminated to 50,000 

dpm/ft2 (DuPont 1983–1989).