Page 1 of 56

DOE Review Release 05/05/2020

Site Profile for The Carborundum Company

ORAUT-TKBS-0061 Rev. 00

Effective Date: 04/23/2020

Supersedes: None

Subject Expert(s): Mutty M. Sharfi, Joseph Guido, Thomas Tomes, and Richard J. Traub

Document Owner 

Approval: Signature on File

Mutty M. Sharfi, Document Owner

Approval Date: 04/21/2020

Concurrence: Signature on File

John M. Byrne, Objective 1 Manager

Concurrence Date: 04/21/2020

Concurrence: Signature on File

Scott R. Siebert, Objective 3 Manager

Concurrence Date: 04/21/2020

Concurrence: Vickie S. Short Signature on File for

Kate Kimpan, Project Director

Concurrence Date: 04/21/2020

Approval: Signature on File

Timothy D. Taulbee, Associate Director for Science

Approval Date: 04/23/2020

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-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 2 of 56

 

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

04/23/2020 00 New technical basis document initiated for The Carborundum 

Company, Niagara Falls, New York. Incorporates formal internal and 

NIOSH review comments. Training required: As determined by the 

Objective Manager. Initiated by Mutty M. Sharfi.

TRADEMARK INFORMATION

Carborundum® and Hexoloy® are registered trademarks of Saint-Gobain Ceramics & Plastics in the 

United States and/or other countries.

Fiberfrax® is a registered trademark of Unifrax in the United States and/or other countries.

Globar® is a registered trademark of Sandvik Wire and Heating Technology Corporation in the United 

States and/or other countries.

All other trademarks are the property of their respective owners.
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 3 of 56

 

TABLE OF CONTENTS

SECTION TITLE PAGE

Acronyms and Abbreviations.................................................................................................................. 6

1.0 Introduction ................................................................................................................................. 8

1.1 Purpose........................................................................................................................... 9

1.2 Scope.............................................................................................................................. 9

2.0 Site Description.........................................................................................................................10

2.1 Plant and Process Descriptions ....................................................................................10

2.1.1 First Operational Period Process Descriptions, 1943.....................................13

2.1.2 First Residual Period, 1943 to 1958 ...............................................................14

2.1.3 Second Operational Period Process Descriptions, 1959 to 1967...................14

2.1.4 Second Residual Period, 1968 to 1992..........................................................19

2.2 Radiological Exposure Sources from Operations .........................................................20

2.2.1 Internal Radiological Exposure Sources from Operations..............................22

2.2.1.1 First Operational Period, 1943 ....................................................22

2.2.1.2 First Residual Period, 1943 to 1958............................................22

2.2.1.3 Second Operational Period, 1959 to 1967 ..................................22

2.2.1.4 Second Residual Period, 1968 to 1992.......................................23

2.2.2 External Radiological Exposure Sources from Operations.............................23

2.2.2.1 External Radiological Exposure Sources by Radiation 

Type ............................................................................................23

2.2.2.1.1 Photon...................................................................23

2.2.2.1.2 Beta.......................................................................24

2.2.2.1.3 Neutron ................................................................. 24

2.2.2.2 External Radiological Exposure Sources by Period ....................24

2.2.2.2.1 First Operational Period, 1943 ..............................24

2.2.2.2.2 First Residual Period, 1943 to 1958......................24

2.2.2.2.3 Second Operational Period, 1959 to 1967 ............24

2.2.2.2.4 Second Residual Period, 1968 to 1992.................26

3.0 Occupational Medical Dose ......................................................................................................26

4.0 Occupational Onsite Ambient and Environmental Dose ...........................................................27

5.0 Occupational Internal Dose.......................................................................................................27

5.1 Available Internal Monitoring Data ................................................................................27

5.2 Methods for Bounding Unmonitored Internal Dose .......................................................27

5.2.1 First Operational Period, 1943........................................................................28

5.2.2 First Residual Dose Period, 1943 to 1958......................................................28

5.2.3 Second Operational Period, 1959 to 1967 .....................................................29

5.2.3.1 Uranium.......................................................................................30

5.2.3.2 Plutonium ....................................................................................31

5.2.3.3 Summary of Second Operational Period Intake Rates................31

5.2.4 Second Residual Dose Period, 1968 to 1992 ................................................32

6.0 Occupational External Dose .....................................................................................................33

6.1 Available External Monitoring Data ...............................................................................33

6.2 Methods for Bounding Unmonitored External Dose......................................................33

6.2.1 First Operational Period, 1943........................................................................34
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6.2.2 First Residual Period, 1944 to 1958 ...............................................................35

6.2.3 Second Operational Period, 1959 to 1967 .....................................................35

6.2.3.1 Uranium.......................................................................................36

6.2.3.2 Plutonium ....................................................................................37

6.2.3.2.1 Geometry and Materials........................................37

6.2.3.2.2 Radiation Source Terms........................................38

6.2.3.2.3 Dose Equivalent Calculations................................39

6.2.3.2.4 Simulation Results.................................................39

6.2.3.3 X-Ray Diffraction .........................................................................40

6.2.4 Second Residual Period, 1968 to 1992..........................................................42

7.0 Attributions and Annotations .....................................................................................................42

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

Glossary................................................................................................................................................50

ATTACHMENT A RADIOLOGICAL CONTRACT WORK DURING THE SECOND 

OPERATIONAL PERIOD ..................................................................................52

LIST OF TABLES 

TABLE TITLE PAGE

2-1 Radiological work during the first operational period ................................................................14

2-2 Isotopic analysis of plutonium mixture ......................................................................................20

2-3 Summary of Carborundum exposure sources over the contract timelines ...............................21

2-4 Principal radiation emissions from natural uranium and short-lived decay products ................23

2-5 Radioactive material inventory in 1962.....................................................................................25

5-1 Inhalation intake rates for the first operational period...............................................................28

5-2 Ingestion intake rates for the first operational period................................................................28

5-3 Uranium intake rates for the first residual period ......................................................................29

5-4 Inhalation intake rates for the second operational period .........................................................30

5-5 Ingestion intake rates for the second operational period ..........................................................30

5-6 RU mixture ratios ......................................................................................................................30

5-7 Isotopic analysis of plutonium mixture ......................................................................................32

5-8 Plutonium mixture isotopic to total alpha activity ratios.............................................................32

5-9 Total alpha intake rates for the plutonium mixture during the second residual period..............33

6-1 Penetrating dose rates for the first operational period..............................................................34

6-2 Nonpenetrating dose rates for the first operational period........................................................34

6-3 External dose rates for the first residual period ........................................................................36

6-4 Penetrating dose rates for the second operational period ........................................................37

6-5 Nonpenetrating dose rates for the second operational period ..................................................37

6-6 Isotopic analysis of plutonium mixture ......................................................................................38

6-7 Isotopic analysis of uranium mixture.........................................................................................38

6-8 External dose from second operational period for plutonium....................................................40

A-1 Radiological contract work during the second operational period.............................................52
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LIST OF FIGURES 

FIGURE TITLE PAGE

2-1 The Carborundum Company site on Buffalo Avenue in Niagara Falls, New York....................10

2-2 Carborundum facility for investigating refractory materials .......................................................12
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ACRONYMS AND ABBREVIATIONS 

AEC U.S. Atomic Energy Commission

ANSI American National Standards Institute

AWE atomic weapons employer

°C degrees Celsius

cm centimeter

d day

DCF dose conversion factor

DOE U.S. Department of Energy

DOL U.S. Department of Labor

dpm disintegrations per minute

DU depleted uranium

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

EU enriched uranium

ft foot

g gram

GE General Electric Company

GSD geometric standard deviation

H*(10) ambient dose equivalent at 10 millimeters depth in tissue

Hp(10) personal dose equivalent at 10 millimeters depth in tissue

HHM Herring-Hall-Marvin

hr hour

HT organ dose equivalent

ICRP International Commission on Radiological Protection

in. inch

keV kiloelectron-volt, 1,000 electron-volts

kg kilogram

lb pound

m meter

MeV megaelectron-volt, 1 million electron-volts

mg milligram

mL milliliter

min minute

NBS National Bureau of Standards

NDA Nuclear Development Corporation of America

NIOSH National Institute for Occupational Safety and Health

NU natural uranium

ORAU Oak Ridge Associated Universities

ORNL Oak Ridge National Laboratory
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PHS Public Health Service

ppm parts per million

R roentgen

R exposure

RU recycled uranium

SEC Special Exposure Cohort

SRDB Ref ID Site Research Database Reference Identification (number)

TBD technical basis document

TCC The Carborundum Company

UNC United Nuclear Corporation

UPu uranium-plutonium (alloy)

(UPu)C uranium-plutonium (alloy) carbide

USC United States Code

wt% weight percent

XRD X-ray diffraction analysis

yr year
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1.0 INTRODUCTION

Technical basis documents (TBDs) and site profile documents are not official determinations made by 

the National Institute for Occupational Safety and Health (NIOSH) but are rather general working 

documents that provide historical background information and guidance to assist in the preparation of 

dose reconstructions at particular U.S. Department of Energy (DOE) or Atomic Weapons Employer 

(AWE) facilities or categories of DOE or AWE facilities. They will be revised in the event additional 

relevant information is obtained about the affected DOE or AWE facility(ies), such as changing 

scientific understanding of operations, processes, or procedures involving radioactive materials. 

These documents may be used to assist NIOSH staff in the evaluation of Special Exposure Cohort 

(SEC) petitions and the completion of individual dose reconstructions under Part B of the Energy 

Employees Occupational Illness Compensation Program Act of 2000 (EEOICPA).

In this document the word “facility” is used to refer to an area, building, or group of buildings that 

served a specific purpose at a DOE or AWE facility. It does not mean nor should it be equated to an 

“AWE facility” or a “DOE facility.” The term “AWE facility” is defined in EEOICPA to mean “a facility, 

owned by an atomic weapons employer, that is or was used to process or produce, for use by the 

United States, material that emitted radiation and was used in the production of an atomic weapon, 

excluding uranium mining or milling” [42 United States Code (USC) 7384I(5)]. On the other hand, a 

DOE facility is defined as “any building, structure, or premise, including the grounds upon which such 

building, structure, or premise is located—(A) in which operations are, or have been, conducted by, or 

on behalf of, the [DOE] (except for buildings, structures, premises, grounds, or operations ... 

pertaining to the Naval Nuclear Propulsion Program); and (B) with regard to which the [DOE] has or 

had—(i) a proprietary interest; or (ii) entered into a contract with an entity to provide management and 

operation, management and integration, environmental remediation services, construction, or 

maintenance services” [42 USC 7384I(12)]. The DOE determines whether a site meets the statutory 

definition of an AWE facility and the U.S. Department of Labor (DOL) determines if a site is a DOE 

facility and, if it is, designates it as such.

Under EEOICPA, a Part B cancer claim for benefits must be based on an energy employee’s eligible 

employment and occupational radiation exposure at a DOE or AWE facility during the facility’s 

designated time period and location (i.e., a “covered employee with cancer”). After DOL determines 

that a claim meets the eligibility requirements under Part B of EEOICPA, DOL transmits the claim to 

NIOSH for a dose reconstruction. EEOICPA provides, among other things, guidance on eligible 

employment and types of radiation exposure to be included in an individual dose reconstruction. 

Under EEOICPA, eligible employment at an AWE facility is categorized as employment either (1) 

during “a period when the [AWE] was processing or producing, for the use by the United States, 

material that emitted radiation and was used in the production of an atomic weapon, excluding 

uranium mining and milling,” (i.e., the operational period); or (2) during a period that NIOSH has 

determined that “there is a potential for significant residual contamination outside of the period in 

which weapons-related production occurred” (i.e., the residual contamination period) [42 USC 

7384I(3)].

The EEOICPA definition for eligible AWE employment during the operational and the residual 

contamination periods creates two statutory frameworks directing types of radiation exposures to be 

included in individual dose reconstructions. For employment falling within an AWE facility’s 

operational period, NIOSH includes radiation exposures incurred in the performance of duty, such as 

medical X-rays received as a condition of employment for participating in DOE projects at an AWE 

facility in dose reconstructions. Additionally, the total measured, occupational radiation exposure 

during an operational period may include radiation exposure contributed by the Naval Nuclear 

Propulsion Program at the AWE facility and any radiation exposure received from the production of 

commercial radioactive products that were concurrently manufactured by the AWE facility during the 

operational period. In contrast, only two categories of radiation exposure are included in dose 
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reconstructions for claims involving employment during the residual contamination period [42 USC 

7384n(c)(4)]. First, NIOSH must include exposures to radiological contaminants resulting from 

activities that had a nuclear-weapon nexus or conducted by or on behalf of the DOE (with an 

exclusion of activities related to, among other things, the Naval Nuclear Propulsion Program) that took 

place during the operational period [42 USC 7384n(c)(4)(A)]. Second, radiation doses from sources 

not included in the first category but cannot be distinguished through reliable documentation should 

also be included in dose reconstructions [42 USC 7384n(c)(4)(B)]. Furthermore, NIOSH does not 

include doses from medical X-rays performed during the residual contamination period in dose 

reconstructions because all DOE-related activities have ceased during the residual contamination 

period, and thus any medical X-ray performed during the residual contamination period is not a

condition of employment for participating in DOE-related activities [NIOSH 2007].

Likewise, NIOSH does not consider the following types of exposure as those incurred in the 

performance of duty as a condition of employment for DOE-related activities at an AWE facility. 

Therefore, these exposures are not included in dose reconstructions for either the operational or 

residual contamination period [NIOSH 2010]:

• Background radiation, including radiation from naturally occurring radon present in 

conventional structures, and

• Radiation from X-rays received in the diagnosis of injuries or illnesses or for therapeutic 

reasons.

1.1 PURPOSE

This site profile provides methods for dose reconstruction for The Carborundum Company in Niagara 

Falls, New York.

1.2 SCOPE 

The covered operational periods for Carborundum are from June 1943 through September 1943 and 

from 1959 through 1967. The residual radiation periods are from October 1943 through 1958 and from 

1968 through 1992.

In June of 1943, the Carborundum Company at its Globar Plant and Buffalo Avenue locations 

performed experimental grinding of uranium metal using a centerless grinder. The actual location of 

this work is unknown. Uranium slugs were received in June and shipped back in September 1943. 

From 1959 through 1967, the company used powder fabrication techniques to manufacture uranium, 

plutonium, and carbide pellets for a U.S. Atomic Energy Commission (AEC) research program. The 

Hanford facility supplied Carborundum with materials during that period.

Carborundum performed work during the 1950s that is not covered under EEOICPA, including 

fabricating nuclear fuel elements for commercial purposes and producing zirconium, hafnium, and 

titanium for AEC's special reactor materials program.

During the period of residual contamination, as designated by NIOSH and as noted in the dates 

above, employees of subsequent owners and operators of this facility are also covered under 

EEOICPA. 

Section 2.0 describes facilities and operations at the site. Sections 3.0 through 6.0 discuss 

occupational medical, environmental, internal, and external dose, respectively. Attributions and 

annotations, indicated by bracketed callouts and used to identify the source, justification, or 

clarification of the associated information, are presented in Section 7.0. 
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2.0 SITE DESCRIPTION

2.1 PLANT AND PROCESS DESCRIPTIONS

The Carborundum Company was located at 1920 Buffalo Avenue (address on file from 1921 to 2001) 

in Niagara Falls, New York. The company was founded on September 21, 1891, after the discovery of 

crystal stones that chemical analysis revealed to be silicon carbide. Because the silicon carbide 

powder was considered an excellent abrasive material, the company became known as the 

electrochemical and electrometallurgical center of the world. The abrasive products appeared on 

grinding wheels, sharpening stones, and sandpaper. Carborundum developed newer and softer 

manmade abrasives, and before long it was a national and international enterprise [TCC 1991]. 

The Globar Plant is also listed in the covered facility definition for Carborundum. During the 1920s, the 

Wireless Resistor Company of America, based in Milwaukee, Wisconsin, pioneered the use of silicon 

carbide in an electric heating element called a “Globar.” In 1927, Carborundum purchased that 

company, by then called the Globar Corporation, and moved its production to Niagara Falls. A new 

facility was constructed on Hyde Park Boulevard and the transfer was complete in August 1928 

[Advameg 2015, p. 3; TCC 1991, p. 44; NYSDEC 2009]. 

No documentation has been found about the exact physical size of the facility or the exact number of 

buildings for any period at the site. Figure 2-1 shows a historical view of the facility’s main offices and 

plant buildings. From interviews, it is estimated that 30 to 50 buildings were on site at Buffalo Avenue 

by the second operational period [ORAUT 2015a, 2015b]; one interviewee suggested that, at that 

time, the site encompassed about 200 acres [ORAUT 2015c]. In 1953, new modern quarters for the 

Research and Development Division were completed; these quarters occupied over 60,000 ft2 in 

Building 1. This facility included complete laboratory and mechanical equipment; a battery of 

experimental, high-temperature electric furnaces; high-temperature and electronic microscopes; an 

analytical X-ray installation; sonic graders; a research machine shop; an extensive technical library; 

and one of the most comprehensive patent reference departments in the country [TCC 1991]. 

Figure 2-1. The Carborundum Company site on Buffalo Avenue in Niagara Falls, New York [TCC no 

date, p. 12]. 
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Records show that Carborundum employed about 6,000 to 7,000 employees during the mid-to-late 

1940s. Limited documentation has been found about the number of employees in later years up to the 

point in 1983 when the plant was closed and the remaining employees at the site lost their jobs 

[Kostoff 2008]. 

The Carborundum Niagara Falls location was involved with the Manhattan Engineer District (MED) 

programs in 1943 and did work for AEC from 1959 through 1967. 

The 1943 work involved experimental centerless-grinding of uranium metal using different abrasives. 

It is assumed the 1943 work could have been performed at either the Buffalo Avenue location or the 

Globar Plant location, although no information on the location of that work is currently available. 

Carborundum was also involved in nuclear fuel development work for the AEC from 1959 through 

1967. The 1959 through 1967 work was performed in a building at the Buffalo Avenue location. The 

processes involved during these two separate AEC operational periods varied considerably. The 

following sections discuss the available information on Carborundum operations for the MED and 

AEC during these two periods.

DuPont, on behalf of the U.S. Government, subcontracted different companies to perform various 

types of work turning uranium billets into finished slugs for use in the Clinton and Hanford piles. In 

June 1943, DuPont had unfinished slugs delivered to Carborundum to determine the type of abrasive 

wheel and optimum speeds appropriate for production grinding; this experimental grinding was 

performed in June 1943.

Throughout the late 1940s and 1950s, between the first and second covered operational periods, 

Carborundum became a very successful company in the field of industrial technology and grew more 

sophisticated and complex, attracting many talented research scientists to Niagara Falls. In 1953, the 

company completed modern new quarters for its Research and Development Division, which 

developed new products such as Fiberfrax, a ceramic-fiber high-temperature insulation.

In 1959, under Contract No. AT (40-1)-2558, Carborundum did work for the U.S. Atomic Energy 

Commission (AEC) as part of the AEC Fuel Cycle Development Program. The objective of this work 

was to develop refractory uranium materials possessing sufficient advantage over uranium dioxide to 

warrant their use as reactor fuels. The initial contract covered the period from May 1959 through 

December 1960 [Taylor and McMurtry 1961a, p. 7]. The contract was modified and extended to 

continue this work. A letter from September 19, 1962, discusses inventory and instructions for 

disposal of the government-owned source and special nuclear materials in relation to the closeout of 

this contract [Rose 1962, p. 2]. 

Building 1 was the location of uranium and plutonium work from 1959 to 1967. Over the years, 

additions were added to Building 1. These additions were known as Buildings 4 and 16. However, all 

of the nuclear research work was done on fourth floor on the western side of Building 1 [ORAUT 

2015b; ORAUT 2015e]. The X-ray laboratory was on the second floor, as was the spectrographic 

analysis [ORAUT 2015e].

In 1960, Carborundum completed a Central Laboratory facility upgrade for investigating the synthesis 

and fabrication of refractory materials containing plutonium in such forms as carbides, silicides, 

oxides, and nitrides, which was an addition to the uranium contract work. These materials are toxic 

and some are very sensitive to oxygen and moisture, especially in a finely divided form. To work with 

these materials, a leak-tight glovebox system was required. In addition, a decision to fabricate mainly 

by sintering at atmospheric pressure, rather than in a vacuum, required the glovebox to have a 

carefully controlled inert atmosphere. The facility was also protected by alarms and safety devices

that were in continuous operation. The facility operated on a one-shift, five-day week basis [Saulino et 

al. 1962]. This facility was in the Central Laboratory; it was 15 ft wide, 48 ft long and 8.5 ft high with 
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enameled steel-paneled walls and ceiling and vinyl floor covering (see Figure 2-2). This area had a 

change room (11 by 15 ft) and a work space (15 by 37 ft). A helium purification and recirculation 

system serviced the building and occupied a 12-by 24-ft space in an adjacent room [Saulino et al.

1962, p. 3]. The Central Laboratory (also known as the Central Facility) refers to the fourth floor of 

Building 1. 

Figure 2-2. Carborundum facility for investigating refractory materials [Saulino et al. 1962, p. 3]. 

Of the gloveboxes indicated in Figure 2-2, numbers 1, 2, and 6 operated with an air atmosphere and 

numbers 3, 4, and 5 operated with a high-purity helium atmosphere. The gloveboxes averaged 3 ft 

high, 3.5 ft wide, and 5 ft long. They were constructed of welded aluminum plate with full side safetyplate glass windows. The air and helium glovebox systems were connected by a vacuum lock 

between numbers 2 and 3, while the remaining boxes (with the exception of number 6) were 

connected by two-layered flexible plastic tubing. Materials could be moved into or out of the box 

system by the pouching technique (which can also be referred to as bag outs), or directly through the 

O-ring-sealed sliding door of the number 1 box, which was maintained at a low level of contamination 

[Saulino et al. 1962].

Between 1959 and 1965, Carborundum was a subcontractor to United Nuclear Corporation (UNC), 

formerly known as Nuclear Development Corporation of America (NDA), under various contracts. 

UNC performed conceptual design, fuel evaluation, and fuel irradiation. Carborundum fabricated the 

fuel. Both companies operated plutonium-handling facilities [Strasser and Taylor 1963a].

From February 1, 1964, through October 30, 1965, Carborundum was subcontracted to UNC to study 

UPu monoxides. This work was sponsored jointly by AEC and the Joint U.S.-Euratom Research and 

Development Program [Forbes et al. 1966].
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Carborundum performed work with the AEC under contract No. AT (30-1)-3713 from May 23, 1966,

through February 28, 1967. The work studied the preparation of mixed-carbide fuel using 

coprecipitation and the synthesis of (UPu)C [McMurtry 1967].

During the mid-1960s and into the late 1970s, upon completion of AEC-related work, the company 

refocused on its core ceramic technology, moving beyond the capital goods market into the steel, 

paper, plastics, pollution control, and china industries. In the mid-1970s, Carborundum began the 

development of pressureless sintered alpha silicon carbide, which marked its entry into the world of 

structural ceramics. At the same time, Carborundum fought off a hostile takeover attempt by Eaton 

Corporation, only to be purchased by Kennecott Copper Corporation. Through the 1980s, 

Carborundum’s name was changed twice before returning to the Carborundum name in 1988. During 

this time, the company was reorganized into three operating companies. Silicon carbide continued to 

be one of the company’s core minerals with the development of Hexoloy alpha silicon carbide 

products. The company resumed its traditional investment focus in research, development, and 

capital expansion, and moved into development of materials for the growing semiconductor industry.

A significant change occurred in 1983 when the Buffalo Avenue plant was closed and 650 people lost 

their jobs. In 1987, British Petroleum acquired Standard Oil and its Carborundum subsidiary. During 

this time, the company developed aluminum nitride substrates and ceramic packages for the 

semiconductor industry and continued developing new uses for its Fiberfrax technology while 

maintaining global leadership in sales of its Globar heating elements. By 1990, St. Gobain Ceramics & 

Plastics purchased the Carborundum abrasives unit [Advameg 2015; Niagara Gazette 2006].

A memorandum from Oak Ridge National Laboratory (ORNL) Region 1 dated June 23, 1993, provides 

followup information about potentially contaminated sites. The memorandum states that Carborundum

Research Center on Buffalo Avenue was surveyed at the time of closure and that additional 

information was required to remove this site from the list [ORNL 1993]. Subsequent information for the 

nuclear material license number at Carborundum indicates the site was cleared from the ORNL list in 

1993 [ORNL 1999].

2.1.1 First Operational Period Process Descriptions, 1943 

The 1943 Carborundum experimental grinding operation for DuPont was for the purpose of 

determining the type of abrasive wheel to use and the optimum speeds to maintain during a 

production grinding job. The project report has a list of project correspondence that indicates there 

was a letter issued May 17, 1943, granting approval to send one uranium rod to Carborundum for 

centerless grinding experiments [DuPont 1945]. Details in the text of the report and shipping records 

do not indicate that a rod was sent, but indicate that 10 Clinton-sized unfinished slugs were shipped to 

Carborundum for experimental grinding to determine the type of abrasive wheel to use and the 

optimum speeds to maintain during a production grinding job. Shipping and receiving, and 

accountability records show Carborundum taking receipt of 30 lb of slugs from Herring-Hall-Marvin 

(HHM) Safe Company, one of the DuPont subcontractors, on June 1, 1943. Based on the most 

common size of Clinton slugs in the report (finish size: 1.1 in. diameter by 4 in. long), 30 lb of 

unfinished slugs would be nominally equivalent to 10 Clinton-sized unfinished slugs [Clinton 1943, 

p. 14; DuPont 1945, pp. 89, 103, 233, 273].

The shipping and receiving records indicate that Carborundum actually returned 33 lb of slugs to HHM 

Safe Company on September 27, 1943, which is 3 lb more than it received in June. The 3-lb 

discrepancy was noted in accountability records and presumably could be from differences in 

measured weights or possibly contaminated residues added to the return shipment (both the project 

report text and shipping records indicate that sweepings, machine turnings, and residues from various 

subcontractors had to be recovered and returned, but there is no such detailed information for the 

limited machining work done by Carborundum). Table 2-1 presents the information associated with 

the slug-grinding operation [TCC 1944; Clinton 1943; 1944; DuPont 1945, p. 273].
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Table 2-1. Radiological work during the first operational period.

a

Type of work Radionuclides Amounts Report type Project number

Grinding to determine the 

appropriate type of abrasive 

wheel and optimum speed for 

production grinding.

Uranium Ten 

unfinished 

slugs totaling 

30 lb

Metal Fabrication Program

Dummy Slug Program and 

Unbounded Slug Program

Clinton Engineer 

Works

Project 1553

a. Source: DuPont [1945, p. 103].

In a letter to DuPont on July 2, 1943, Carborundum reported on centerless grinding tests using a 

specific grinding wheel and various setups and abrasives. Although some chatter still existed after a 

particular test, various dressing speeds were tried. By using a 26-in./min traverse of the diamond, 

seven pieces were ground without chatter. Two other pieces were used at a slower traverse speed.

The letter also states that there was one smaller piece. Carborundum returned 10 pieces according to 

DuPont instructions. This document only reported on the results obtained and did not include the 

actual setup, radiological exposure potential, or airborne potential [Currie 1943, p. 5]. 

2.1.2 First Residual Period, 1943 to 1958

After World War II, Carborundum embarked on an ambitious commercial expansion plan.

Improvement of traditional product lines was part of this expansion. The company upgraded and 

expanded facilities to become more competitive in the postwar era. The Niagara Falls facilities were 

modernized and new facilities were built or purchased in other areas across the United States and 

Canada.

Carborundum was involved with many projects during the first residual period, many not specifically at 

the Buffalo Avenue plant. Carborundum began development of its Fiberfrax ceramic fiber and, in 

1952, began to market its first commercial applications [Advameg 2015]. In October 1954, a new line 

of tool room wheels known as the V-40 line made a debut. The development of the V-40 wheels at the 

Bonded Abrasives Division was based on input and suggestions gathered in the field from grinding 

machine operators [TCC 1991, p. 73]. 

Beginning in 1955, Carborundum was involved with the production of silicon carbide for structural 

materials for the Aircraft Nuclear Propulsion Department of General Electric Company (GE). The GE 

contract went from September 28, 1955, to September 27, 1956. Carborundum proposed and was 

granted an extension to September 28, 1957 [TCC 1956]. A second extension was granted into 1958 

[TCC 1957]. A second periodic report was issued in May 1958 [TCC 1958]. This contract was 

identified as commercial work and therefore is not included in the covered period evaluation.

Several former Carborundum employees who worked during the first residual period were 

interviewed. One former employee stated he worked in different departments in the Diamond Wheel 

Department and also worked on a lathe. He made diamond insets to cut different kinds of metals 

[ORAUT 2015d]. Another former employee stated he was involved with the synthesis of ceramic 

materials, borides, carbides, nitrides, and silicides. He handled enriched 10B and processed over 

2,000 lb that was converted to boron carbide, which was not radioactive. He also stated he made 

thorium oxide and thorium carbide in the early stages of his work (ca. 1955) [ORAUT 2015e]. This 

thorium work is not considered covered AEC work; therefore, any exposures associated with thorium 

work is not covered under EEOICPA. 

2.1.3 Second Operational Period Process Descriptions, 1959 to 1967

During the second operational period, Carborundum worked as a prime or subcontractor on many 

contracts for the AEC, including UNC. Table A-1 in Attachment A provides a list of the contracts within

this operational period with brief descriptions of the work. Some of these contracts are discussed in 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 15 of 56

 

more detail in the subsequent text. There were seven contracts that covered the work during this 

second operational period (1959 to 1967). 

Synthesis and Fabrication of Uranium Refractory Compounds

• Contract AT-(40-1)-2558 covered uranium work from May 1959 through December 1960.

However, this contract was not officially closed until the end of 1962 [Cope 1962, pp. 3–4]. The 

purpose of this work was to develop methods to synthesize uranium mononitride (UN), 

uranium carbide (UC), and uranium disilicide (U3Si2). Many batches of UC were made with 

batch sizes ranging from about 30 g to 6 lb. This work was part of the AEC Fuel Development 

Program [Taylor and McMurtry 1961a, p. 13]. This was the beginning of the uranium contract 

work and covered AEC work for the second operational period.

This work is described in Summary Report, Synthesis and Fabrication of Refractory Uranium 

Compounds from February 1961 [Taylor and McMurtry 1961a]. The report covers the period from May 

1959 through December 1960.

The object of the investigation was the development of refractory uranium materials possessing 

sufficient advantage over UO2 to warrant their use as reactor fuels [Taylor and McMurtry 1961a]. To 

this end, the various properties of these materials had to be examined. The materials chosen for 

examination consisted of UC, UN, and the silicide U3Si2, all of which have higher densities than UO2

[Taylor and McMurtry 1961a]. The work program was divided into three phases [Taylor and McMurtry 

1961a, p. 10]:

1. Development of methods for synthesis of the compounds.

2. Fabrication of the synthesized materials into bodies suitable for testing.

3. Determination of properties of the materials such as thermal conductivity, thermal expansion, 

and high-temperature strength.

The majority of the work was conducted on small samples of various solutions of the uranium. For 

example, the chemical analysis included a representative batch of 1,500 g of UC that was prepared 

from an unpelletized mix of uranium, combined carbon, uncombined carbon, nitrogen, iron, and 

oxygen. It appears that at various stages of the experimentation it was necessary to use different 

furnaces or enclosures. The types of furnaces and enclosures that were available included 

atmosphere induction furnaces, muffle furnaces, a vacuum induction furnace, nitriding furnaces, a 

quench furnace, a hot-pressing furnace, a thermal conductivity furnace, a high-temperature modulusof-rupture apparatus, a high-temperature furnace, and gloveboxes [Taylor and McMurtry 1961a].

Another aspect of the work involved synthesis experiments with UC. Three approaches were 

considered for the preparation of UC: 

1. Reduction of an oxide (UO2 or U3O8) by carbon. For this experiment, carbon was heated with 

both UO2 and U3O8 to produce UC. The reaction mixture was usually prepared for furnacing as 

follows: the oxide and carbon were mixed by dry ball-milling for 24 hours in a rubber-lined mill 

with stainless-steel balls and then pressed into pellets measuring 0.625 by 0.625 in. This was 

done at 15,000 to 20,000 lb/in.2 using about 2% of water as a temporary binder [Taylor and 

McMurtry 1961a, p. 11]. It is unknown how many experiments were run or how much uranium 

was used for each experiment. However, many batches of UC were made by heating 

stoichiometric mixtures of UO2 and carbon in the vacuum induction furnace at 1,750 °C to 

1,800 °C. The size of the batches varied from about 30 g to 6 lb [Taylor and McMurtry 1961a, 

p. 13]. The resulting mixtures underwent an X-ray analysis to determine the characteristics of 

the resulting compounds.
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 16 of 56

2. Reaction of ammonium diuranate and carbon. This experiment was based on the assumption 

that ammonium diuranate would decompose to U3O8 under the reaction conditions and the 

carbon would then react with the U3O8 to form uranium carbide (uranium monocarbide). The 

pellets were heated in a ceramic tube furnace in an argon atmosphere. A temperature of about 

700 °C was reached in approximately 20 minutes and the maximum temperature of 1,700 °C 

was reached in about 3 to 4 hours. The pellets were held at 1,700 °C for 1 hour and then 

allowed to cool in argon to room temperature [Taylor and McMurtry 1961a, p. 14].

3. Reaction of uranium and carbon. This method of preparation was used exclusively in 

connection with a simultaneous synthesis and fabrication process described above for 

fabrication of uranium carbide (uranium monocarbide) [Taylor and McMurtry 1961a, p. 14].

The exact quantities used in each experiment are not known. However, information from a 

September 19, 1962, contract closeout notification indicated that Carborundum notified the AEC of the 

radioactive material quantities on hand and requested disposal instruction before the closeout of 

contract AT(40-1)-2558 [Rose 1962].

Several former employees were interviewed to discuss the work that they performed at Buffalo 

Avenue [ORAUT 2015c; ORAUT 2015e]. They provided the following insight:

• All nuclear work in the facility was done on the fourth floor.

• Uranium ceramic compounds were fabricated with depleted and enriched uranium. 

• At first, uranium was not carefully controlled because it was considered low-level work and 

therefore not a hazard; there were only minor restrictions. Workers were allowed to dress 

casually. Safety requirements were tightened once larger quantities of uranium were received.

• The work did involve the use of gloveboxes and furnaces. Gloveboxes were used for uranium 

work to control acid fumes, and eventually filters were installed. Uranium gloveboxes were in 

more than one room. However, small quantities of uranium were processed outside of a 

glovebox in a room under negative pressure.

• Plutonium work was performed only in a special room separate from the uranium work.

• One of the former workers recalled wearing radiation badges but could not recall an exact time 

frame. The worker also recalled that the site performed contamination surveys and collected 

uranium samples in the 1960s.

Synthesis and Study of Uranium-Plutonium Carbide Pellets

• Contract AT-(30-1)-2303 was part of the Carbide Fuel Development Program initiated in May 

1959. Design and construction of a facility for carbide fabrication at Carborundum was 

completed in 1960. The equipment was tested by work with UC before the startup of 

operations with plutonium in March 1961 (the first shipment of Pu was received in June 1960).

Seven batches of PuC were made by mixing PuO2 and carbon and then furnacing at differing 

temperatures and hold times [Strasser and Taylor 1961, p. 14].

• Contract AT-(30-1)-2899 covered work from May 15, 1959, through October 15, 1965. As part 

of the Carbide Fuel Development Program, this work was concerned with the technology of 

UC-PuC fuels. The major goals were to produce (UPu)C and obtain data on its irradiation 

behavior for long burnups and at high-power generation rates [Strasser and Stahl 1965].
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 17 of 56

Synthesis and Study of Uranium/Plutonium Monoxides

• Contract AT-(30-1)-3305 covered work from February 1, 1964, through October 30, 1965.

Carborundum was the subcontractor to UNC and conducted fabrication studies of uranium and 

plutonium monoxides in helium. Mixtures of UO2-PuO2 were used to synthesize UPu

compositions [Forbes et al. 1966, pp. 5–6].

• Contract AT(30-1)-3713 was associated with the AEC Fuel Cycle Development and studied 

the preparation of mixed carbide fuel using coprecipitation and the synthesis of (UPu)C. This 

contract covered the period May 23, 1966, through February 28, 1967 [McMurtry and Taylor 

1966; McMurtry 1967].

Out-of-Pile Properties of Mixed Uranium Plutonium Carbides

• Contract AT-(30-1)-3118 covered the period from February 6, 1962, through December 6, 

1963, and was closely coordinated with the AEC-sponsored Carbide Fuel Development 

Program. Carborundum was a subcontractor to UNC under which UNC performed the property 

determinations and Carborundum prepared the fuel samples. Four 100-g synthesis batches 

were prepared from UO2, PuO2, (UPu)C. UO2, PuO2, and carbon powder was synthesized in 

70- to 100-g batches [Strasser et al. pp. 17, 22]

• Contract AT-(30-1)-3254 was closely coordinated with the Carbide Fuel Development 

Program. The goal under this contract was to determine the out-of-pile properties of (UPu)C 

that have the most significant effect on the operational characteristics of the fuel. The powder 

fabrication initiated under AT (30-1)-2889 continued with this contract [Stahl and Strasser et al. 

1963, pp. 10, 14].

As noted by the contracts information, the first plutonium shipment was received in June 1960 and 

plutonium work began in March 1961. Carborundum was contracted to mix uranium and plutonium 

fuels as part of its work on the Carbide Fuel Development program in support of UNC. While different 

mixtures were possible, the most common carbide mixture included 95% uranium and 5% plutonium.

All work with radioactive material was done in the Central Research Laboratory, which was 

specifically constructed to support this work. The classified work with plutonium was conducted on the 

fourth floor in a secure room that required an escort for entry [ORAUT 2015b].

Several former employees were interviewed to discuss the work that they performed at Buffalo 

Avenue. Some of the work consisted of mixing uranium and plutonium oxides together in relatively 

small amounts (milligrams to grams) to make pellets. The results of each experiment were recorded in 

logbooks, and the pellets were sent for spectroanalysis to determine the specific compounds that 

resulted. The employee also indicated that people wore lab coats (with the sleeves taped) and a halfface dust mask when working with radioactive material. The plutonium area was under negative 

pressure and was a clean room system; employees checked themselves out with a frisker, but 

sometimes a safety person helped [ORAUT 2015c].

Another interviewee described work on the fourth floor of the Central Research Laboratory in the 

special room built for plutonium work as including fabricating U-Pu pellets. Limits were in place that 

restricted the amount of material in process at any one time. The FBI brought the materials to the 

laboratory and took the pellets away when they were completed. The interviewee said he wore a 

radiation badge and participated in a medical monitoring program [ORAUT 2015b].

An abstract published in Reactor Technology on liquid metal fast breeder reactors discusses the 

Carbide Fuel Development Phase 1 Report for the period from May 15 to September 15, 1959 [AEC 

no date, p. 85]. The abstract references contract AT(30-1)-2303 between NDA and Carborundum.

Subsequently, the Carbide Fuel Development project was the subject of a letter from March 30, 1960, 

to the New York Health and Safety Laboratory. This letter discusses the proposal for Carborundum to 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 18 of 56

 

manufacture ceramic pellets containing PuC mixed with UC (normal enrichment) at its Central 

Research Laboratories in Niagara Falls. Over a period of 3 years, a total of approximately 3 kg of 

plutonium were to be fabricated into pellets. The first shipment of plutonium from Hanford (the only 

shipment during 1960) was to consist of 500 g [Werner 1960]. 

The following processes were to be involved in the fabrication of PuC pellets (operational details 

unspecified):

1. Weighing the PuO2 powder as received from the supplier, 

2. Chemical analysis, 

3. Addition of UO2 and carbon, 

4. Ball milling, 

5. Heating to form the monocarbides, 

6. Crushing, 

7. Chemical and X-ray analysis, 

8. Ball milling, 

9. Cold pressing into pellets, 

10. Sintering into dense form, 

11. Grinding pellets, and

12. Inspection and shipment. 

The results of the Carbide Fuel Development project are documented in many reports, as indicated in 

the listings in the Foreword section of each progress report [Strasser and Stahl 1965]. Handling 

standards for plutonium were established in a planning document, which consisted of the following 

requirements:

• All plutonium handling would be done in a glovebox.

• Any waste or scrap generated in the glovebox would be removed using the pouch method.

• The maximum amount of contained plutonium in storage could not exceed 600 g at any one 

time.

• No single container could contain more than 200 g of plutonium. 

• No more than 200 g of plutonium or uranium-plutonium mix could be in process at any one 

time.

• No more than 100 g of plutonium could be used in any single batch in process, with a 

maximum of two simultaneous batches in operation at any given time.

Each phase of the operation of fuel fabrication and testing was performed in an inert helium 

atmosphere. The minimum critical mass for a water-reflected solution containing 239Pu was identified 

as 510 g, and the recommended safe mass was listed as 250 g. Considering this information, the 

Carborundum pellet process was recommended for approval because of the maximum of 200 g of 

plutonium that would be stored per container or be in process at any one time [Werner 1960]. 

These experiments and others were all part of the Carbide Fuel Development Program, which was 

concerned with the technology of the entire UC-PuC fuel cycle. The major goal of the program was to 

produce (UPu)C and to obtain data on its irradiation behavior for long burnups and at high-power 

generation rates. The program was initiated in May 1959 and, as originally outlined, covered a period 

of about 4.5 years [Strasser and Taylor 1963a, p. 18]. 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 19 of 56

Many of the overall experiments consisted of synthesizing compounds and fabricating them into 

pellets, determining the coefficients of expansion, measuring melting points and vapor pressures,

checking compatibility with other elements at various high temperatures, and performing irradiation 

tests (X-ray diffraction). These procedures involved handling of the radioactive material in one form or 

another to mix the chemicals and make transfers between the many enclosures for individual tests; 

this handling provided potential opportunities for exposure.

Various experiments were performed, and samples analyzed, to develop the optimal method to 

fabricate the mixed carbide fuel pellets. Table A-1 lists the contracts and information on the type of 

work. It has references for various reports that provide more details of the experiments.

X-Ray Diffraction

The ceramic pellets containing PuC-UC were manufactured by Carborundum as a subcontractor to 

UNC. The fuels were evaluated by various means, including X-ray diffraction analysis (XRD) [Werner 

1960]. The X-ray powder diffraction method is used very extensively for compound or phase 

identification [Kehl 1971]. Carborundum used this method to analyze the fuel as part of the fuel 

fabrication process.

In XRD, a very small beam of low-energy monochromatic X-rays irradiates a sample of matter, 

mixed-oxide fuel (PuC-UC) in the case of Carborundum. The X-rays are scattered by the individual 

atoms in the sample. In crystalline samples, the atoms are arranged in a lattice pattern. The scattered 

X-rays from the sample interfere with each other and cause scattered X-rays to be emitted only in 

some directions and not others. This causes a diffraction pattern that can be recorded and analyzed

and provides specific information about the atomic structure of the sample.

2.1.4 Second Residual Period, 1968 to 1992

All covered AEC work at Carborundum was completed in 1967, which marks the end of the second 

operational period and beginning of the second residual period. The residual radioactive materials that 

remained from covered operations occurring after the second (and first) operational period are all that 

must be accounted for in the second residual period. The operations that occurred between 1968 and 

1992 at the Buffalo Avenue facility are of no radiological consequence; these interim operations are 

discussed in the following paragraphs.

There was some information on the nonradiological work that continued at Carborundum during the 

second residual period, which included the following:

• In 1968, Carborundum manufactured some boron carbide powder for GE Atomic Power. Some 

of this material was tested for composition and density by ORNL in 1969 [Ikeuye and Young 

1970].

• In 1968, Carborundum did some studies for Westinghouse Astronuclear Laboratory on 

niobium carbide [Singleton 1969].

• In 1972, Carborundum produced some unirradiated cylindrical pellets of boron carbide for 

testing as part of the Experimental Breeder Reactor No. 2 program [Ruther and 

Greenburg 1972].

Several former Carborundum employees who worked during the second residual period were 

interviewed. One former employee stated that he worked in the mid-1970s and made bulletproof vests 

and armor for PT boats. The base product was carbon. The material was put into ovens to make the 

plating for the armor. Sometimes the plating would be cracked. If the plating could be fixed, it would 

need grinding and smoothing; this created a lot of dust. Masks were not used during this process and 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 20 of 56

 

there was no ventilation [ORAUT 2015d]. The plates for the armor vests were made for the Vietnam 

War and this work was done in Building 14. This building had a firing range to test the armor plating 

[ORAUT 2015a]. 

Although Carborundum is mentioned by name in numerous documents because of their grinding 

wheels, no additional information was identified on any other potentially covered radiological 

operations after 1967.

There are Carborundum annual reports available for 1971, 1972, and 1973 that discuss overall sales 

and expenditures; however, these reports do not discuss any further ongoing AEC-related processes 

[TCC 1972, 1973; 1974]. 

2.2 RADIOLOGICAL EXPOSURE SOURCES FROM OPERATIONS

The radionuclide-specific source terms that are applicable to operational and residual radioactivity 

periods at Carborundum are uranium and plutonium. The following subsections describe the 

radioactive materials applicable to the periods discussed in this section.

In February 1962, the Carborundum Company issued a progress report entitled, Carbide Fuel 

Development. This report described the work done in the uranium carbide-plutonium carbide fuel 

development program. Table 2-2 shows the isotopic analysis of the PuO2 [Strasser and Taylor 1962b, 

p. 15]. 

Table 2-2. Isotopic analysis of 

plutonium mixture. 

Radionuclide % mass

Pu-238 0%

Pu-239 90.7%

Pu-240 7.9%

Pu-241 1.2%

Pu-242 0.1%

As indicated in Strasser and Taylor [1962b, p. 15], Carborundum used plutonium provided by Hanford 

in the study of the preparation of (UPu)C powder. 

In addition, the 1966 final summary report of the Study of Uranium-Plutonium Monoxides Final 

Summary Report [Forbes et al. 1966], indicated that the goal of the study was to find a uraniumplutonium monoxide fuel for water-cooled thermal reactors that would have a heat-generation 

capability better than, and water-corrosion resistance equivalent to, PuO2 and (UPu)O2. 

Plutonium enrichment was employed in this study in anticipation of the day when sufficient plutonium 

would be available to reduce reliance on uranium isotope enrichment facilities. Although early core 

loadings would use 239Pu, subsequent ones could use increasing amounts of 240 Pu to increase the 

reactivity burnup limit of the reactor. Total plutonium concentrations of up to 10% would be introduced 

into the uranium fuel [Forbes et al. 1966, p. 14]. In addition to 239Pu, 240Pu and 241Pu could be sources 

of exposure.

Many of the contracts involving Carborundum overlapped for various periods and involved different 

process materials. Table 2-3 presents Carborundum contracts in parallel timelines; the corresponding 

process materials represent the respective source terms for the periods.
 

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0 Effective Date: 04/23/2020 Page 21 of 56

Table 2-3. Summary of Carborundum exposure sources over the contract timelines.

a

Contract 

or type of work

1943 1944 1945–1954 1955–1958 1959 1960b 1961 1962 1963 1964 1965 1966 1967

Clinton Engineer Works 

Project 1553:

Experimental grinding of 

uranium [DuPont 1945].

U None None None None None None None None None None None None

AT-(40-1)-2558: Synthesis 

and Fabrication of Refractory 

U Compounds [Taylor and 

McMurtry 1961a, 1961b] 

None None None None UO2, 

U3O8, 

UN 

powder, 

U3Si2

UO2, 

U3O8, 

UN 

powder, 

U3Si2

Depleted 

UO2; 

Depleted 

UO2; 

None None None None None

AT(30-1)-2899: Carbide Fuel 

Development Program: Fuel

Fabrication [Strasser and 

Stahl 1965] 

None None None None UC UC, Pu UC, PuC 

powder 

containing 

NU, EU, 

Pu 

UC, PuC 

pellets

Powder 

containing 

NU, EU, 

Pu

UC, 

PuC

UC, PuC 

mixed 

carbides

UC, PuC 

mixed 

carbides

None None

AT(30-1)-2303: Carbide Fuel 

Development [Strasser and 

Taylor 1961; Strasser and 

Stahl 1965]

None None None None None UC, 

UO2, 

Pu 

None None None None None None None

AT[30-1)-3118;

closely coordinated with 

AT(30-1)-2899 [Stahl et al. 

1963]

None None None None None None UPu 

carbides

None None None None None None

AT(30-1)-3254; closely 

related to AT(30-1)-1. 

Studies were a continuation 

of AT(30-1)-2889 [Strasser et 

al. 1963]

None None None None None None None (UPu)C 

80% UC20% PuC

None None None None None

AT(30-1)-3305: Study of UPu

Monoxides; UNC Project2321 [Forbes et al. 1966] 

None None None None None None None None None U, Pu

Depleted 

UO2, 

PuO2, 

UHx, 

UC, UN

U, Pu

Depleted 

UO2, 

PuO2, 

UHx, UC, 

UN

None None

AT (30-1)-3713; Associated 

with the AEC Fuel Cycle 

Development Program: 

Studies of the preparation of 

mixed carbide fuel utilizing 

co-precipitation; synthesis of 

(UPu)C. [McMurtry and 

Taylor 1966]

None None None None None None None None None None None UN; Pu 

(UPu)C 

UN; Pu 

(UPu)C 

a. None indicates there was no corresponding contract activity during this period. 

b. The sources of Pu in 1960 were limited to a shipment received in late 1960; processing did not begin until March 1961. 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 22 of 56

2.2.1 Internal Radiological Exposure Sources from Operations

The primary potential source of internally deposited radioactivity from Carborundum operations was 

inhalation and ingestion of natural uranium (NU), depleted uranium (DU), and enriched uranium (EU) 

and plutonium. Uranium was present at the site as a powder. In addition, 239Pu was present during the 

second operational period.

2.2.1.1 First Operational Period, 1943 

As indicated previously, Carborundum was involved with centerless grinding testing using grinding 

wheels and different abrasives on uranium slugs. The quantity of material identified in the first 

operational period is approximately 30 lb of uranium (10 slugs) that were shipped between 

Carborundum and HHM Safe Company [Clinton 1943, pp. 9, 14]. It was also noted that one rod was 

authorized to be sent to Carborundum on May 17, 1943, for centerless grinding experiments [DuPont 

1945, p. 273]. Based on the shipping records and description of work during the first operational 

period, a determination was made that Carborundum received a total of 10 slugs. The slugs were 

received on June 1, 1943; the grinding work was done that month and results were reported on July 2, 

1943. Return shipment of the slugs was not made until September 27, 1943. DuPont reported that 

there was no required health supervision because of the limited amount of work [Daniels 1944, p. 13]. 

Although the work was limited, centerless grinding of uranium has been known to produce significant 

levels of airborne radioactivity and to create an inhalation and ingestion hazard.

2.2.1.2 First Residual Period, 1943 to 1958

Only the residual materials that were considered a primary source during the first operational period 

need to be considered during the first residual period. Therefore, only natural uranium is considered to 

be a source that must be accounted for during the residual period from 1943 to 1958.

2.2.1.3 Second Operational Period, 1959 to 1967

Work at Carborundum during the second operational period (1959 to 1967) consisted of research and 

development. During this period, Carborundum worked with uranium and plutonium powders and 

chemicals to synthesize fuel pellets and to develop refractory uranium materials possessing sufficient 

advantage over uranium dioxide to warrant their use as reactor fuels. Carborundum fabricated test 

samples of these materials and performed a variety of tests to verify their economic viability and their 

ability to replace uranium dioxide fuels. Although much of the experimentation and testing was 

conducted in enclosures, there was a potential for internal exposure (inhalation or ingestion) during 

the handling of uranium and plutonium powders and chemicals.

From May 1959 through 1962 [Cope 1962, pp. 3–4], Carborundum worked with uranium, under 

contract AT-(40-1)-2558, to develop methods to synthesize UN, UC, and U3Si2 [Taylor and McMurtry 

1961a]. At its Central Research Laboratory in Niagara Falls, Carborundum manufactured ceramic 

pellets that contained PuC mixed with UC (normal enrichment). The first plutonium shipment came 

from Hanford in 1960 and was 500 g [Werner 1960]. However, the equipment was first tested with 

UC. The site then started up operations with plutonium in March 1961 [Strasser and Taylor 1961].

According to an interviewee, the [redacted] work he did was classified and he was the only one in the 

room making pellets with a mixture of uranium and plutonium [ORAUT 2015b].

At the time Carborundum closed out contract AT(40-1)-2558 for source and special nuclear material, it 

had in its possession various amounts of depleted and 10%-EU powder [Rose 1962]. These forms of 

uranium were used in the preparation of UC pellets, and various-sized pieces were used for testing 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 23 of 56

 

physical properties in connection with the Carbide Development Program [Strasser and Taylor 

1962b, p. 15]. 

2.2.1.4 Second Residual Period, 1968 to 1992

As is the case with the first residual period, only the residual materials considered a primary source 

during the second operational period (and any carryover from the first operational period) need to be 

considered during the second residual period. Therefore, uranium and plutonium are considered to be 

sources that must be accounted for during the second residual period from 1968 to 1992. 

2.2.2 External Radiological Exposure Sources from Operations

Based on the available information, the potential for external radiation doses from uranium, uranium 

decay products, and plutonium existed at Carborundum. The following sections discuss the external 

exposure sources for Carborundum workers evaluated in this report. The external sources result in 

the photon and beta radiations in Table 2-4, as well as some potential neutron exposures.

Table 2-4. Principal radiation emissions from natural uranium and short-lived decay products.

a 

Radionuclide Half-life

Beta energy

(max. MeV)

Photon (X or γ) energy

(MeV)

U-238 4.468E+9 yr None X: 0.013 (8.8%)

Th-234 24.1 d 0.096 (25%) X: 0.013 (9.6%)

Th-234 24.1 d 0.189 (73%) γ: 0.063 (3.8%)

Th-234 24.1 d 0.189 (73%) γ: 0.093 (5.4%)

Pa-234m 1.17 min 2.28 (98.6%) γ: 0.765 (0.2%)

Pa-234m 1.17 min ~1.4 (1.4%) γ: 01.001 (0.6%)

U-235 7.038E+8 yr None X: 0.013 (31%)

U-235 7.038E+8 yr None X: 0.090-0.105 (9.3%)

U-235 7.038E+8 yr None γ: 0.144 (10.5%)

U-235 7.038E+8 yr None γ: 0.163 (4.7%)

U-235 7.038E+8 yr None γ: 0.186 (54%)

U-235 7.038E+8 yr None γ: 0.205 (4.7%)

Th-231 25.5 hr 0.206 (15%) X: 0.013 (71%)

Th-231 25.5 hr 0.288 (49%) γ: 0.026 (14.7%)

Th-231 25.5 hr 0.305 (35%) γ: 0.084 (6.4%)

U-234 244,500 yr None X: 0.013 (10.5%)

U-234 244,500 yr None γ: 0.053 (0.2%)

a. Source: NIOSH [2011]. The above table shows the principal radiation emissions from natural uranium and its short-lived 

decay products that are of concern for external radiation (not including bremsstrahlung).

2.2.2.1 External Radiological Exposure Sources by Radiation Type

2.2.2.1.1 Photon

Carborundum conducted work with NU, depleted uranium (DU), and EU as well as plutonium. 

External exposures to photon radiation would have resulted from the immediate progeny in the

uranium decay chain. The progeny that result in the most significant photon exposures include 234Th

and 234mPa [PHS 1970]. Note that these isotopes have relatively short half-lives and can be assumed 

to be in equilibrium with the parent 238U. Because of their short half-lives, the exposure potential from 

these isotopes is the same as that of the parent and will not be considered separately. Plutonium itself 

is not a major contributor to photon dose. However, 239Pu decays by alpha emission to 235U, whose 

short-lived progeny do contribute to total photon exposure. Table 2-4 shows the primary isotopes, 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 24 of 56

 

principal emissions, and photon energies associated with natural uranium and short-lived progeny. In 

addition, in a plutonium mixture, the decay of 241Pu to 241Am, which decays with the emission of a 60-

keV photon, is the predominant source of photon exposure associated with plutonium mixtures. 

2.2.2.1.2 Beta

Radiation fields from uranium are frequently dominated by contributions from its progeny. For 

example, nearly the entire beta radiation field from DU comes from the 234mPa and, to a lesser extent, 

from 234Th. 

Table 2-4 shows the principal beta emitters and their energies for uranium. Because 239Pu decays 

directly to 235U, the beta emitters present in this decay chain are already accounted for in Table 2-4. 

As indicated, there are a significant number of high-energy beta radiations that represent a shallow 

dose exposure concern for site workers. Workers who handled the uranium would have received 

shallow dose exposures. The primary exposure areas would have been the hands and forearms, the 

neck and face, and other areas of the body that might not have been covered.

2.2.2.1.3 Neutron

The source of neutrons would result from the work with uranium and plutonium in the gloveboxes 

during the second operational period. Neutron doses were calculated using the MCNP6.2 transport 

code. Dose rates were calculated at 1 ft and 1 m from the center of the fuel pellet. Based on the 

nature of the work and the forms of the materials, neutrons are only considered to be a potential 

external exposure source during the second operational period. 

2.2.2.2 External Radiological Exposure Sources by Period

2.2.2.2.1 First Operational Period, 1943 

As indicated previously, Carborundum was involved with testing centerless grinding with grinding 

wheels and different abrasives. This work was performed on 10 uranium slugs that were shipped 

between Carborundum and HHM Safe Company [Clinton 1943, pp. 9, 14]. 

2.2.2.2.2 First Residual Period, 1943 to 1958

Based on the removal of the exposure sources from the site during the first residual period, the 

external doses and potential for external exposures are considerably lower than that of the associated 

operational period. 

2.2.2.2.3 Second Operational Period, 1959 to 1967

The second operational period included quantities of both uranium and plutonium that contributed to 

the onsite source term. Between 1959 and 1967, Carborundum had seven contracts for a variety of 

experimental procedures. The contracts included work with both uranium and plutonium.

The experimental procedures during the second operational period included different research and 

development methods, such as synthesis and fabrication of refractory uranium compounds, 

fabrication of plutonium pellets, fuel fabrication, and evaluation of mixed uranium-plutonium carbide 

fuels. Shipping and receipt records, contract descriptions, and licensing information provide an 

indication of the quantities of radioactive material that was on the Carborundum site. Quantities 

included 3 kg of plutonium over a 3-year period, 1,500 g of UN, 3 lb of UC, and various batches of 

different UPu alloy carbides. Table A-1 lists known quantities.
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Although most of the experimental work was conducted in gloveboxes, there were potential sources of 

exposure for the workers. The work involved the investigation of methods for synthesizing the 

compounds, fabrication of the materials for testing, and determining the properties of these materials.

Another major effort was the carbide fuel development program, which involved fabrication and testing 

uranium and plutonium fuel pellets and studying out-of-pile properties of mixed UPu carbides. 

While many of these procedures do not provide the amounts of radioactive material, several other 

experiments do. Note that the dates in the parentheses in the bullets below are approximate based on 

progress and summary reports. 

• During the synthesis of uranium monocarbide a representative batch of UC consisted of 

1,500 g (1959 to 1960) [Taylor and McMurtry 1961a, p. 11]. 

• In another experiment designed to determine the effect of the thermal history of the UC 

powder (time and temperature used in the synthesis) on its subsequent sinterability, each 

experiment used 453.6 g of UO2 [Taylor and McMurtry 1961b, p. 7]. The number of 

experiments conducted has not been stated (1961). 

• During the synthesis of thermal conductivity specimens a total of 550 g of UO2, PuO2 and 

carbon powder was synthesized in 70- to 100-g batches (1961 to 1963) [Stahl et al. 1963a, 

p. 22]. 

• One of the steps in the evaluation of the out-of-pile properties of mixed uranium-plutonium 

carbides at the 5% PuC level was the preparation of the powder. In this procedure, about 

400 g of (U0.95 Pu0.05)C0.98 powder was synthesized for the fabrication of test specimens (1959

to 1965) [Strasser and Stahl 1965, p. 77; Strasser and Taylor 1963a, p. 12]. 

• Other experiments during the fuel development program consisted of the fuel synthesis for the 

fabrication of UC-PuC irradiation testing. In one experiment, the natural uranium powder 

required for the specimens was synthesized. Reaction of the 760-g batch of PuO2-UO2-C 

yielded approximately 580 g of an essentially single-phase (U0.8Pu0.2)C0.95 solid solution. In its 

synthesis, the reaction batch was divided into 16 lots of about 50 g each (1962 to 1963) 

[Strasser and Taylor 1962a, p. 11; 1963b, p. 19]. 

Other material that was available at Carborundum was documented in its letter to the AEC. On 

September 19, 1962, Carborundum notified the AEC of the closeout of contract AT(40-1)-2558 and 

requested instructions for the disposal of the radioactive material it possessed [Rose 1962]. Table 2-5 

lists the radioactive material Carborundum had at that time. 

Table 2-5. Radioactive material inventory in 1962. 

Contract: NU

Material category and uranium type

Amount

(g)

As metallic uranium in powder form, as received 9,260 U

As uranium monocarbide in powder form, as received 44 UC

As uranium nitride in powder form, as received 27 UN

As chemical residues 14 U

Contract: DU

Material category and uranium type

Amount

(g)

As uranium dioxide in powder form, as received 13,379 U

As U3O8 in powder form contains carbon as an impurity 3,170 U
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Contract: 10% EU

Material category and uranium type

Amount

(g)

As metallic uranium in powder form, as received 54 U

As uranium dioxide in powder form, as received 829 U

As U3O8 in powder form contains carbon as an impurity 609 U

As UC, on wipers, used containers and crucibles (questionable recovery) 72 U

License

Material category and uranium type

Amount

(g)

Depleted uranium as metallic turnings 340 U

Depleted uranium monocarbide as shot 47 U

X-Ray Diffraction Machines

An additional external exposure source that must be accounted for during the second operational 

period is the XRD machines for analyzing the UC-PuC materials. The greatest hazard from XRD 

machines is external exposure from the primary beam. This can occur most commonly during 

alignment procedures, when the target must be aligned with the output port, the sample with the 

primary beam, and the detector or film holder with the reflected beam [Lubenau 1969]. If the X-ray 

beam is inadvertently turned on during alignment, the operator’s fingers or hands could be 

inadvertently exposed to the primary beam. Historically, these types of accidents are the primary 

hazard from XRD machines [Thomas 1971, p. 145]. No evidence of these types of radiation accidents 

has been found at Carborundum.

The scattered radiation is of low energy and occurs in small, directional beams. Radiation leakage 

through small cracks in the shielding or other components would also tend to be of low energy, and in 

small, directional beams. Operators are not usually monitored for radiation exposure because of the 

small likelihood of the very small beams interacting with the small dosimeter device [Blatz 1971, 

p. 76]. 

2.2.2.2.4 Second Residual Period, 1968 to 1992

As in the case of the first residual period, based on the removal of the exposure sources from the site 

during the second residual period, the external doses and potential for external exposures are 

considerably lower than that of the associated operational period. 

3.0 OCCUPATIONAL MEDICAL DOSE

Medical X-rays are not required to be considered during residual radiation periods. Applicability of 

occupational medical dose during the operational periods is as follows:

• First Operational Period, 1943. According to ORAUT-OTIB-0006, Dose Reconstruction from 

Occupational Medical X-Ray Procedures [ORAUT 2019a], and ORAUT-OTIB-0079, Guidance 

on Assigning Occupational X-ray Dose Under EEOICPA for X-Rays Administered Off Site

[ORAUT 2017], in the absence of information to the contrary, it is assumed that medical X-ray 

examinations were performed on site during the first operational period. Therefore, one

posterior-anterior radiographic chest X-ray screening should be assumed to have been 

performed for workers during the first operational period. Doses should be assigned based on 

ORAUT-OTIB-0006.

• Second Operational Period, 1959 to 1967. No data relevant to medical X-rays at Carborundum 

for the second operational period was identified. According to ORAUT-OTIB-0006, Dose 

Reconstruction from Occupational Medical X-Ray Procedures [ORAUT 2019a], and ORAUT-
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OTIB-0079, Guidance on Assigning Occupational X-ray Dose Under EEOICPA for X-Rays 

Administered Off Site [ORAUT 2017], in the absence of information to the contrary, it is 

assumed that medical X-ray examinations were performed on site during the second 

operational period. Therefore, preemployment, annual, and termination posterior-anterior 

radiographic chest X-ray screenings should be assumed to have been performed for workers 

during the second operational period. Doses should be assigned based on ORAUT-OTIB0006. 

4.0 OCCUPATIONAL ONSITE AMBIENT AND ENVIRONMENTAL DOSE

Sections 5.0 and 6.0 account for onsite ambient and environmental exposures in the assessment of 

unmonitored and residual internal and external worker intakes and doses. 

5.0 OCCUPATIONAL INTERNAL DOSE

5.1 AVAILABLE INTERNAL MONITORING DATA

During a review of Carborundum’s records no urinalysis, whole-body counts, or lung counts were 

found for either of the two operational periods or residual periods. However, interviews with former 

workers [ORAUT 2015b, 2015c, 2015e] indicated that the site did collect urine samples. If a claim file 

contains personal monitoring records, contact the Principal Scientist for Internal Dosimetry or Principal 

Scientist for AWEs on how to assess the data.

Uranium and plutonium air sample data have been found for the second operational period (1959 to 

1967). These air sample results were used to provide a basis for estimates of internal doses that are 

favorable to the claimant in accordance with Battelle-TBD-6000, Site Profiles for Atomic Weapons 

Employers that Worked Uranium Metals [NIOSH 2011]. 

5.2 METHODS FOR BOUNDING UNMONITORED INTERNAL DOSE

Individual exposures are assigned based on the specific work performed using the categories 

described below [NIOSH 2011]: 

• Operator. Individuals who operated the process equipment or routinely handled radiological 

materials. This is the default dose category for dose reconstructions when there is insufficient 

information to place a worker in a lower dose category. 

• Laborer (and radiological work support personnel). Individuals who were in close contact with 

the radiological materials product for a portion of the working day. This category includes 

maintenance workers, laboratory workers, health physics monitors, and so forth, who might 

have occasionally been in contact with radioactive material in the performance of duties. If 

information in a claim is insufficient to determine whether or not a worker fits this description, 

the operator category should be used. 

• Supervisor (and nonradiological work production personnel). Individuals who routinely worked 

in the production areas and might have been periodically in the vicinity of processing. This 

includes supervisory staff, engineers, and individuals who were not in contact with the 

radiological materials but who worked routinely in the production areas. If information in a 

claim is insufficient to determine that the worker did not handle radioactive material in the 

performance of their duties, a higher dose category should be used. 

• Clerk (or other). Individuals who worked in the environment outside of the production areas 

where radiological work was being performed. This includes office workers and nonradiological 
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production workers who are clearly documented to be at a physically different location from the 

radiological work (e.g., a different building). If work location cannot be determined for a claim, 

one of the other categories of exposure should be used.

5.2.1 First Operational Period, 1943

For the first operational period, there are no bioassay data for Carborundum employees. Internal 

doses from uranium intakes during the first operational period are estimated using the data from the 

pre-1951 “Machining” operation in Battelle-TBD-6000 [NIOSH 2011]. The intake rates for inhalation 

and ingestion are provided in Table 5-1 and 5-2. Given the chemical and physical forms of uranium at 

the site, only type M or S solubility should be evaluated. 

Table 5-1. Inhalation intake rates for the first operational period (dpm/calendar day).a

Period Operator Laborer

Supervisor and

clerkb

06/01/1943–09/27/1943 43,632 21,816 10,909

a. Intakes are assigned as a lognormal distribution with a geometric standard deviation (GSD) of 5.

b. Due to the limited information on the location of the uranium slug work, the Supervisor and Clerk job categories were 

combined. 

Table 5-2. Ingestion intake rates for the first operational period (dpm/calendar day).a

Period Operator Laborer

Supervisor and

Clerkb

06/01/1943–09/27/1943 895 446 224

a. Intakes are assigned as a lognormal distribution with a GSD of 5.

b. Due to the limited information on the location of the uranium slug work, the Supervisor and Clerk job categories were 

combined. 

The work at Carborundum was done for the purpose of experimentally determining the appropriate 

type of abrasive wheel and the optimum speeds to maintain. Carborundum was not the site where the 

actual final uranium production grinding operation was performed. The information from this 

operational period at Carborundum denotes that the scale of this uranium operation was very limited 

(30 lb of slugs) and occurred in June 1943. The 30 lb consisted of 10 slugs that were received from 

HHM Safe Company by Carborundum in June 1943 and returned in September 1943. Therefore, the 

Battelle-TBD-6000 method based on large-scale and large-quantity operations serves to support 

bounding internal exposures for Carborundum’s first operational period [NIOSH 2011].

Exposures associated with residual material after September 27, 1943, are covered in the section 

below describing the first residual period.

5.2.2 First Residual Dose Period, 1943 to 1958

Residual uranium inhalation intake rates are based on guidance in Battelle-TBD-6000 [NIOSH 2011]. 

A settling rate of 0.00075 m/s was assumed for 30 d resulting in a surface contamination level of 

1.07 × 107 dpm/m2. A resuspension factor of 1 × 10-5/m was then used to estimate the initial 

contamination level in the air at the start of the residual period, 106.5 dpm/m3. The inhalation intake 

rate calculated based on that air concentration was then depleted over time based on the adjustments 

in ORAUT-OTIB-0070, Dose Reconstruction During Residual Radioactivity Periods at Atomic 

Weapons Employer Facilities [ORAUT 2012]. 

The intake rates for inhalation and ingestion are provided in Table 5-3. Given the chemical and 

physical forms of uranium at the site, only type M or S solubility should be evaluated. 
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Table 5-3. Uranium intake rates for the first residual period (dpm/calendar day).a,b

Period Inhalation Ingestion

9/28/1943–12/31/1943 841 895

1944 841 895

1945 658 701

1946 515 549

1947 403 430

1948 316 337

1949 247 263

1950 194 207

1951 139 148

1952 109 116

1953 86 91

1954 67 71

1955 52 56

1956 37 40

1957 29 31

1958 23 24

1959 18 19

1960 14 15

1961 11 12

1962 8.6 9.1

1963 6.7 7.2

1964 5.3 5.6

1965 4.1 4.4

1966 3.2 3.4

1967 2.5 2.7

1968 2.0 2.1

1969 1.5 1.6

1970 1.2 1.3

1971 1.0 1.0

1972 0.74 0.79

1973–1992 0.58 0.62

a. Intakes are assigned as a lognormal distribution with a GSD of 5. 

b. Uranium intake rates should be assigned as 100% U-234.

Initial residual uranium ingestion intake rates were assumed to be equivalent to the ingestion rate for 

the Operator job category at the end of the first operational period. This ingestion intake rate was then 

depleted over time based on the adjustments in ORAUT-OTIB-0070 [ORAUT 2012].

Based on Battelle-TBD-6000 [NIOSH 2011], the number of hours worked were reduced from 48 per 

week in 1943, to 44 per week starting in 1951, then to 40 per week starting in 1956.

The intake rates in Table 5-3 apply to all Carborundum workers through 1958. If there is clear 

documentation that a worker was assigned to the Globar Plant, then the worker should be assigned 

residual intakes from Table 5-3 in all applicable years.

5.2.3 Second Operational Period, 1959 to 1967

Air sample results for uranium and plutonium for the second operational period were used to provide 

an intake rate estimate that is favorable to the claimant. The operations during this period were of an 

experimental nature and the sample data are limited in scope. A statistical analysis was performed on 

both the uranium and plutonium sample results. 
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5.2.3.1 Uranium

Doses should be assigned based on airborne dust sampling data for November 1959 and April 1961 

[AEC 1947–1961]. On November 9, 1959, a series of six general area airborne dust samples were 

taken. A second series of three samples, all with positive results, was collected on April 5, 1961. One 

other sample was taken; the sample date is unknown, but it was received on April 19; the record is not 

legible. 

The geometric mean of this air sample data was 0.634 dpm/m3 with a geometric standard deviation 

(GSD) of 4.45. Based on this distribution, the 95th-percentile air concentration was determined to be 

7.38 dpm/m3. This air concentration was assumed to represent the general area and was therefore 

used to calculate the intake rate for the Laborer exposure. 

Based on Battelle-TBD-6000 [NIOSH 2011], the Operator intake rates were assumed to be twice the 

Laborer intake rates, the Supervisor intake rates were assumed to be half the Laborer intake rates, 

and the Clerk’s intake rate was assumed to be 10% of the Supervisor intake rates.

Uranium intake rates for inhalation and ingestion are provided in Tables 5-4 and 5-5, respectively.

Uranium doses are assigned as 100% 234U for individual uranium dose evaluation. Given the chemical 

and physical forms of uranium at the site, only type M or S solubility should be evaluated. Recycled 

uranium (RU) contaminants should be assigned based on Battelle-TBD-6000 [NIOSH 2011] (see 

Table 5-6). 

Table 5-4. Inhalation intake rates for the second operational period (dpm/calendar day).

a

Radionuclide Operator Laborerb Supervisor Clerk

Uranium (1959-1967) 97.10 48.55 24.28 2.428

Plutonium mixture-total alpha 

(1961–1967)

7.650 3.825 1.913 0.191

a. Intakes are assigned as a constant distribution.

b. Based on the level of potential exposure, XRD operators should be assigned the more favorable Laborer exposure 

scenario.

Table 5-5. Ingestion intake rates for the second operational period (dpm/calendar day).

a

Radionuclide Operator Laborerb Supervisor Clerk

Uranium (1959-1967) 2.023 1.012 0.506 0.051

Plutonium mixture-total alpha 

(1961–1967)

0.159 0.080 0.040 0.004

a. Intakes are assigned as a constant distribution.

b. Based on the level of potential exposure, XRD operators should be assigned the more favorable Laborer exposure 

scenario.

Table 5-6. RU mixture ratios.

a

Radionuclide Ratio to U-Activity

Pu-239 0.00246

Np-237 0.00182

Tc-99 0.379

Th-232 2.73E-6

Th-228 2.73E-6

a. Source: NIOSH [2011].

Ingestion rates were based on OCAS-TIB-009, Estimation of Ingestion Intakes [NIOSH 2004].
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5.2.3.2 Plutonium 

Plutonium intake rates are based on airborne dust sampling data for April 1961 and June 1961 [AEC 

1947–1961]. On April 5, 1961, a series of eight airborne dust samples was taken. Two were identified 

as general area samples and two as breathing-zone samples, and four were either without description 

or the description was illegible. All samples on this date had positive results. On June 7, 1961, a 

second series of eight samples was collected. Six of the samples were identified as breathing-zone 

samples, and two as general area samples. Four of the samples had positive results. 

The geometric mean of this air sample data was 0.027 dpm/m3 with a GSD of 9.82. Based on this 

distribution, the 95th-percentile air concentration was determined to be 1.16 dpm/m3.

This air concentration was assumed to be representative of the work area and was therefore used to 

calculate the intake rate for the Operator exposure. Based on Battelle-TBD-6000 [NIOSH 2011], the 

Laborer intake rates were assumed to be half the Operator intake rates, the Supervisor intake rates 

was assumed to be half the Laborer intake rates, and the Clerk intake rates were assumed to 10% of 

the Supervisor intake rates.

Gross alpha plutonium mixture intake rates for inhalation and ingestion are provided in Tables 5-4 and 

5-5, respectively. Given that these intake rates represent total alpha activity, the ratio for the 

plutonium mixture (see Table 5-8 next section) should be applied to determine the intake rate for each 

radionuclide in the mixture. 

Ingestion rates were based on OCAS-TIB-009 [NIOSH 2004].

5.2.3.3 Summary of Second Operational Period Intake Rates

If there is clear documentation that a worker was assigned to the Globar Plant, then the worker should 

be assigned residual intakes from Table 5-3 in all applicable years. Uranium-only work in the second 

operational period started in 1959, and the plutonium mixed carbide fuel pellets work started in 1961. 

The plutonium mixed carbide fuel pellets involved both uranium and plutonium. There was a separate 

uranium laboratory for experiments and fabrication of uranium (only) experimental pieces and fuel 

pellets. The estimated intake rates in the uranium laboratory are based on measured alpha air 

concentrations in the uranium laboratory. The plutonium laboratory was an isolated cell in the same 

building. The plutonium intake rates are based on measured gross alpha air concentrations in the 

plutonium laboratory. In the absence of definitive work locations for all workers, the assigned intake

rates between 1961 and 1967 should be based on the work that results in the exposure most 

favorable to the claimant. Therefore, either the uranium laboratory or the plutonium laboratory should 

be assigned, but not both. This is based on the assumption that a worker was not simultaneously 

exposed in two different areas of the Carborundum facility.

Though the plutonium laboratory used both uranium and plutonium in the fabrication of fuel pellets, 

the intake rates for the plutonium laboratory are based on gross alpha air concentration estimates. 

Because workers could have been exposed to either uranium or plutonium, or a mixture, it is more 

favorable to assume all of gross alpha intake for the plutonium laboratory was 100% plutonium. This 

is because the estimated uranium gross alpha intake rates for the uranium laboratory are greater than 

those for the plutonium laboratory.

In addition, it is assumed that a worker could have been exposed in both laboratories at different 

times for portions of their work. Therefore, the application of the more favorable internal and external 

dose scenario is treated separately to ensure total doses are not underestimated. This means that it is 

acceptable to assign internal exposures based on the more favorable uranium laboratory intake rates 
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and still assign external exposures based on the more favorable plutonium laboratory dose rates, and 

vice versa.

The plutonium was assumed to be weapons grade having the weight fractions shown in Table 5-7 

[Strasser and Taylor 1962b, p. 15]. 

Table 5-7. Isotopic analysis of plutonium 

mixture. 

Radionuclide % mass

Pu-238 0%

Pu-239 90.7%

Pu-240 7.9%

Pu-241 1.2%

Pu-242 0.1%

The activities of the radionuclides at 5 years after separation were calculated using the Radiological 

Toolbox 3.0.0. This resulted in the following ratios of isotope to total alpha activity (Table 5-8). 

Table 5-8. Plutonium mixture isotopic to total 

alphaa activity ratios. 

Radionuclideb Ratio

Pu-239 0.678

Pu-240 0.216

Pu-241 11.740

Am-241 0.106

a. Sum of Pu-239, Pu-240, and Am-241.

b. Pu-242 is considered an insignificant contributor to 

dose and therefore not assessed.

5.2.4 Second Residual Dose Period, 1968 to 1992

Residual inhalation intake rates were based on Battelle-TBD-6000 [NIOSH 2011]. The initial airborne 

contamination level was determined by setting the operational air concentration at a rate of 

0.00075 m/s for 30 days and then resuspended at a rate of 1 × 10-5/m. The inhalation intake rates 

calculated based on those air concentrations were then depleted over time based on the adjustments 

found in ORAUT-OTIB-0070 [ORAUT 2012]. 

The initial uranium intake rate at the start of the residual period was determined to be 

0.94 dpm/calendar day inhalation and 2.023 dpm/calendar day ingestion. This is less than the intake 

rate from the first residual period in 1968 (see Table 5-3). Given that the work location for the second 

operational period was in the research and development building that did not exist in 1943, the first 

residual period uranium intakes are considered more favorable for all years during the second 

residual period. Given the chemical and physical forms of uranium at the site, only type M or S 

solubility should be evaluated. 

Gross alpha plutonium mixture intake rates for inhalation and ingestion are provided in Table 5-9.

Given that these intake rates represent total alpha activity, the ratio for the plutonium mixture 

(Table 5-8), should be applied to determine the intake rate for each radionuclide in the mixture. 

Plutonium ingestion intake rates at the beginning of the residual period were assumed to be 

equivalent to the Operator ingestion intakes from the second operational period. Exposures for this 

second residual period were adjusted based on guidance in ORAUT-OTIB-0070 [ORAUT 2012].
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Table 5-9. Total alpha intake rates for the 

plutonium mixture during the second 

residual period (dpm/calendar day).

a

Period Inhalation Ingestion

1968 0.15 0.159

1969 0.12 0.125

1970 0.091 0.098

1971 0.071 0.077

1972 0.056 0.060

1973 0.044 0.047

1974 0.034 0.037

1975 0.027 0.029

1976 0.021 0.022

1977 0.017 0.018

1978 0.013 0.014

1979 0.0101 0.011

1980 0.0079 0.0085

1981 0.0062 0.0066

1982 0.0048 0.0052

1983 0.0038 0.0041

1984 0.0030 0.0032

1985 0.0023 0.0025

1986 0.0018 0.0020

1987 0.0014 0.0015

1988 0.0011 0.0012

1989 0.00088 0.00094

1990 0.00069 0.00073

1991 0.00054 0.00058

1992 0.00042 0.00045

a. Intakes are assigned as a constant distribution.

Summary of Second Residual Period Intake Rates

If there is clear documentation that a worker was assigned to the Globar Plant, then the worker should 

be assigned residual intakes from Table 5-3 in all applicable years. 

The uranium intake rates in Table 5-3, or the plutonium mixture intake rates in Table 5-9, whichever 

results in the higher dose, apply to all Carborundum workers. The choice of which scenario, uranium 

or plutonium, is more favorable is independent of the selection of exposure scenario that is more 

favorable for external exposures.

6.0 OCCUPATIONAL EXTERNAL DOSE

6.1 AVAILABLE EXTERNAL MONITORING DATA

No Carborundum or DOE documentation was identified that would show that the operational areas or 

the workers were personally monitored for external radiation during the two operational or two residual 

radiation periods. However, interviews with former workers [ORAUT 2015b, 2015c, 2015e, 2016] 

indicated that the site did provide monitoring badges. If a claim file contains personal monitoring 

records, contact the Principal Scientist for External Dosimetry or Principal Scientist for AWEs on how 

to assess the data.

6.2 METHODS FOR BOUNDING UNMONITORED EXTERNAL DOSE

Individual exposures are assigned based on the specific work performed, using the same categories 

for internal dose: Operator, Laborer, Supervisor, and Clerk (Section 5.2). 
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6.2.1 First Operational Period, 1943 

As indicated above, the operations for this period at Carborundum were very limited (30 lb of slugs) 

and occurred in June 1943. The 30 lb consisted of 10 slugs that were received from HHM Safe 

Company by Carborundum in June 1943 and returned in September 1943. Therefore, exposures 

associated with residual material after September 27, 1943, are covered in the section below 

describing the first residual period.

Given that the guidance in Battelle-TBD-6000 [NIOSH 2011] is based on large-scale and largequantity operations, the exposure rates for the machining (grinding) work in Carborundum slug 

grinding experiments was considered bounding for Carborundum exposures.

Individual external doses should be assigned based on the specific work as shown below. Daily dose 

rates are provided in Tables 6-1 and 6-2. 

• Operator’s basis. 0.000524 rem/hr @ 1 ft rate based on an array of 10 slugs [NIOSH 2011; 

Table 6.1]. This results in an annualized penetrating dose rate of 0.6288 rem/yr or 0.00172 

rem/calendar-day assuming 50% of a 2,400-hr work year [NIOSH 2011]. 

• Laborer basis. 0.0000519 rem/hr @ 1 m rate based on an array of 10 slugs [NIOSH 2011, 

Table 6.1]. This results in an annualized penetrating dose rate of 0.06228 rem/yr or 0.000171 

rem/calendar-day assuming 50% of a 2,400-hr work year [NIOSH 2011]. 

Table 6-1. Penetrating dose rates for the first operational period (rem/calendar day).

a

Period Operator Laborer

Supervisor and

Clerkb

06/01/1943–09/27/1943 1.72E-03 1.71E-04 8.53E-05

a. Doses are assigned as a lognormal distribution with a GSD of 5.

b. Assumed to be 50% of the Laborer’s dose rate [NIOSH 2011].

Based on Battelle-TBD-6000 [NIOSH 2011], the nonpenetrating (beta) dose rate for the operator is 

assumed to be 10 times the penetrating dose rate.

Table 6-2. Nonpenetrating dose rates for the first operational period (rem/calendar day).

a

Period Operator Laborerb

Supervisor and

Clerkc

06/01/1943–09/27/1943 1.72E-02 8.61E-03 8.61E-04

a. Doses are assigned as a lognormal distribution with a GSD of 5.

b. Assumed to be 50% of the Operator’s dose rate [NIOSH 2011].

c. Assumed to be 10% of the Laborer’s dose rate [NIOSH 2011].

Penetrating doses should be applied as 100% 30- to 250-keV photons assuming acute exposure and 

deep dose equivalent (Hp(10)) to organ dose equivalent (HT) dose conversion factor (DCF) values in 

accordance with OCAS-IG-001 [NIOSH 2007]. Nonpenetrating doses should be applied as >15-keV 

electrons using an acute exposure rate and a DCF in accordance with ORAUT-OTIB-0017, 

Interpretation of Dosimetry Data for Assignment of Shallow Dose [ORAUT 2005]. 

Surface contamination and air submersion DCFs for uranium are based on Battelle-TBD-6000 

[NIOSH 2011]. Battelle-TBD-6000 [NIOSH 2011] Tables 3.9 and 3.10 were used to estimate the 

exposure rates from residual contamination.

Surface Contamination

• Deep: 3.94 × 10-13 R/hr/dpm/m2

• Shallow: 3.82 × 10-11 rad/hr/dpm/m2
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Air Submersion 

• Deep: 2.46 × 10-12 R/hr/dpm/m3

The surface and airborne contamination levels for the operational period were determined to be 

1.07 × 107 dpm/m2 and 5,480 dpm/m3, respectively. This results in an operational exposure rate for 

June 1, 1943, to September 27, 1943, of 2.77 × 10-5 R/calendar day penetrating and 

2.68 × 10-3 R/calendar day nonpenetrating. These doses are assigned to all workers as a lognormal 

distribution with a GSD of 5.

Penetrating doses associated with operations should be applied as 100% 30- to 250-keV photons 

using the acute exposure rate and exposure (R)-to-organ (HT) DCF values in accordance with OCASIG-001 [NIOSH 2007]. Penetrating doses associated with surface contamination and submersion 

should be applied as 71.8% <30 keV; 17.8% 30- to 250-keV, and 10.4% >250-keV photons [NIOSH 

2011], given that the penetrating doses are mainly attributed to the contaminated surface, using acute 

exposure rate and exposure (R)-to-organ (HT) DCF values in accordance with OCAS-IG-001 [NIOSH 

2007]. Nonpenetrating doses should be applied as >15-keV electrons using an acute exposure rate 

and a DCF in accordance with ORAUT-OTIB-0017 [ORAUT 2005].

6.2.2 First Residual Period, 1944 to 1958

Residual surface contamination and air submersion DCFs from uranium are based on Battelle-TBD6000 [NIOSH 2011]. The Battelle-TBD-6000 [NIOSH 2011] surface contamination and air submersion 

DCFs in Section 5.2.2 were used to calculate the first residual period external dose exposure rates.

The initial surface and airborne contamination levels for the start of the first residual period were 

determined to be 1.07 × 107 dpm/m2 and 1.065 × 102 dpm/m3, respectively. This results in an initial 

exposure rate of 1.01 × 10-2 R/yr penetrating and 9.77 × 10-1 rad/yr nonpenetrating. These exposure 

rates were then depleted over time based on the adjustments in ORAUT-OTIB-0070 [ORAUT 2012].

The penetrating and nonpenetrating exposure rates are provided in Table 6-3.

Based on Battelle-TBD-6000 [NIOSH 2011], the number of hours worked were reduced from 48 per 

week in 1943, to 44 per week starting in 1951, then to 40 per week starting in 1956.

These exposure rates apply to all Carborundum workers.

Penetrating doses associated with surface contamination and submersion should be applied as 

71.8% <30 keV; 17.8% 30- to 250-keV, and 10.4% >250-keV photons [NIOSH 2011], given that the 

penetrating doses are mainly attributed to the contaminated surface, using acute exposure rate and 

exposure (R)-to-organ (HT) DCF values in accordance with OCAS-IG-001 [NIOSH 2007].

Nonpenetrating doses should be applied as >15-keV electrons using an acute exposure rate and a 

DCF in accordance with ORAUT-OTIB-0017 [ORAUT 2005].

6.2.3 Second Operational Period, 1959 to 1967

The more favorable exposure scenario between uranium, plutonium, or X-ray diffraction should be 

assigned. All three scenarios occurred in different work locations. However, the assumption made on 

the more favorable internal exposure scenario does not dictate the assumed scenario for external

exposure. That is, the choice of the more favorable internal and external scenarios is independent to 

ensure total doses are not underestimated. This means that it is acceptable to assign internal 

exposures based on the more favorable uranium laboratory intake rates and still assign external 

exposures based on the more favorable plutonium laboratory or X-ray diffraction, or vice versa.
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Table 6-3. External dose rates for the first residual 

period.a

Period Penetrating

(R/yr)

Nonpenetrating

(rad/yr)

09/28/1943–12/31/1943 2.62E-03 2.54E-01

1944 1.01E-02 9.77E-01

1945 7.89E-03 7.65E-01

1946 6.18E-03 5.99E-01

1947 4.84E-03 4.69E-01

1948 3.79E-03 3.67E-01

1949 2.96E-03 2.87E-01

1950 2.33E-03 2.26E-01

1951 1.67E-03 1.62E-01

1952 1.30E-03 1.26E-01

1953 1.03E-03 9.94E-02

1954 8.01E-04 7.76E-02

1955 6.27E-04 6.08E-02

1956 4.47E-04 4.33E-02

1957 3.49E-04 3.39E-02

1958 2.74E-04 2.65E-02

1959 2.14E-04 2.08E-02

1960 1.68E-04 1.63E-02

1961 1.31E-04 1.27E-02

1962 1.03E-04 9.97E-03

1963 8.06E-05 7.81E-03

1964 6.31E-05 6.12E-03

1965 4.94E-05 4.79E-03

1966 3.87E-05 3.75E-03

1967 3.03E-05 2.94E-03

1968 2.37E-05 2.30E-03

1969 1.86E-05 1.80E-03

1970 1.45E-05 1.41E-03

1971 1.14E-05 1.10E-03

1972 8.92E-06 8.65E-04

1973–1992 6.98E-06 6.77E-04

a. Doses are assigned as a lognormal distribution with a GSD of 5.

6.2.3.1 Uranium

Given that the guidance found in Battelle-TBD-6000 [NIOSH 2011] is based on large-scale and largequantity operations, the exposure rates for the machining (grinding) work for slug production was 

considered bounding for Carborundum exposures. 

Individual external doses should be assigned based on the specific work using the categories 

described below. Daily dose rates are provided in Tables 6-4 and 6-5. 

• Operator basis. 0.000231 rem/hr at 1-ft rate based on a flat plate [NIOSH 2011, Table 6.1]. 

This results in an annualized penetrating dose rate of 0.231 rem/yr or 0.000633 rem/calendarday assuming 50% of a 2,000-hr work year [NIOSH 2011]. 

• Laborer basis. 0.0000278 rem/hr at 1-m rate based on a flat plate [NIOSH 2011, Table 6.1]. 

This results in an annualized penetrating dose rate of 0.0278 rem/yr or 0.000076 

rem/calendar-day assuming 50% of a 2,000-hr work year [NIOSH 2011]. 
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Table 6-4. Penetrating dose rates for the second operational period (rem/calendar day).

a

Period Operator Laborer Supervisorb Clerkc

1959–1967 6.33E-04 7.62E-05 3.81E-05 3.81E-06

a. Doses are assigned as a lognormal distribution with a GSD of 5.

b. Assumed to be 50% of the Laborer’s dose rate [NIOSH 2011].

c. Assumed to be 10% of the Supervisor’s dose rate [NIOSH 2011].

Table 6-5. Nonpenetrating dose rates for the second operational period (rem/calendar day).

a

Period Operatorb Laborerc Supervisord Clerke

1959–1967 1.11E-02 5.55E-03 5.55E-04 n/a

a. Doses are assigned as a lognormal distribution with a GSD of 5.

b. Based on MCNP analysis of uranium metal plate [ORAUT 2018a]. 

c. Assumed to be 50% of the Operator’s dose rate [NIOSH 2011].

d. Assumed to be 10% of the Laborer’s dose rate [NIOSH 2011].

e. No exposure assumed [NIOSH 2011].

Penetrating doses associated with operations should be applied as 100% 30- to 250-keV photons 

using acute exposure rate and deep dose equivalent (Hp(10)) to organ dose equivalent (HT) DCF 

values in accordance with OCAS-IG-001 [NIOSH 2007]. Nonpenetrating doses should be applied as 

>15-keV electrons using an acute exposure rate and a DCF in accordance with ORAUT-OTIB-0017 

[ORAUT 2005]. 

Surface contamination and air submersion dose correction factors for uranium are based on BattelleTBD-6000 [NIOSH 2011]. 

The surface and airborne contamination levels for the second operational period were determined to 

be 2.87 × 104 dpm/m2 and 14.77 dpm/m3, respectively. This results in an operational exposure rate for 

1959 to 1967 of 6.22 × 10-8 R/calendar day penetrating and 6.01 × 10-6 rad/calendar day 

nonpenetrating. These doses should be assigned to all workers.

Penetrating doses associated with surface contamination and submersion should be applied as 

71.8% <30 keV; 17.8% 30- to 250-keV, and 10.4% >250-keV photons [NIOSH 2011], given that the 

penetrating doses are mainly attributed to the contaminated surface, using acute exposure rate and 

exposure (R)-to-organ (HT) DCF values in accordance with OCAS-IG-001 [NIOSH 2007].

Nonpenetrating doses should be applied as >15-keV electrons using an acute exposure rate and a 

DCF in accordance with ORAUT-OTIB-0017 [ORAUT 2005].

6.2.3.2 Plutonium

From 1961 through 1967, as described in Section 2.1.3, Carborundum operated a facility for the study 

and fabrication of plutonium refractory materials for an AEC fuel development program. 

6.2.3.2.1 Geometry and Materials

Pellet Geometry

The radiation source for these dose calculations is a small pellet of UPu carbide having a density of 

12.8 g/cm3 [Strasser and Stahl 1965]. The carbide fuel pellets had a range of densities. This density 

(12.8 g/cm3) was mentioned in the text of the final report as starting material for experiments related to 

out-of-pile properties of mixed UPu carbides [Stahl et al. 1963, p. 14]. The chosen density was 

identified as the density of fuel that had been sintered without sintering aids. This density was chosen 

to maximize the amount of fuel in a single fuel pellet. Fuel that had been sintered with a sintering aid 

(0.1 without Ni) had a higher density of 13.1 g/cm3 [Stahl et al. 1963, p. 14]. Dose estimates were 

made for a single pellet that is a cylinder 0.2 in. in diameter and 0.2 in. tall [Strasser and Stahl 1965]. 

The pellets were assumed to be unclad.
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Glovebox Geometry

The pellets were assumed to be housed in a glovebox 3 ft high, 5 ft long, and 3.5 ft deep [Saulino et 

al. 1962]. The side walls, roof, and floor of the glovebox were 0.25-in. welded aluminum plate. The 

front and back walls were 0.25-in. safety glass. The safety glass consisted of two 0.125-in. layers of 

plate glass and a 15-mil inner layer of polyvinyl butyral that inhibited shattering of the glass.

In addition to the glovebox, the model contained a concrete back wall, a ceiling, and a floor to 

generate albedo. Steel panels 0.0625 in. thick were installed on the ceiling and walls of the room.

6.2.3.2.2 Radiation Source Terms

Isotopic Compositions of Uranium and Plutonium

The plutonium was assumed to be weapons grade having the weight fractions shown in Table 6-6 

[Strasser and Taylor 1962b]. The uranium was enriched as shown in Table 6-7. Three isotopic 

compositions for plutonium were used during the course of the experiments at Carborundum. The 

composition for dose reconstruction purposes was chosen based on the material that had the highest 

weight fraction of 241Pu. Plutonium-241 decays to 241Am, which drives the photon dose because it 

emits a 60-keV photon that penetrates shielding more readily than the lower energy photons from 

plutonium isotopes.

Table 6-6. Isotopic analysis of plutonium 

mixture. 

Radionuclide % mass

Pu-238 0%

Pu-239 90.7%

Pu-240 7.9%

Pu-241 1.2%

Pu-242 0.1%

Table 6-7. Isotopic analysis of uranium 

mixture. 

Radionuclide % mass

U-234 0.132%

U-235 24%

U-238 75.868%

The isotopic composition of the uranium for the carbide fuel pellets was not explicitly stated in the 

reports. An enrichment of 24% was chosen to be consistent with material known to have been used at 

Carborundum [Strasser and Taylor 1962b]. The calculated dose rate from the fuel pellets is not 

strongly influenced by the isotopic composition of the uranium for the fuel pellets.

Photon Source Calculations

The photon component of the dose rates from (U0.8Pu0.2)C is due mainly to the radioactive progeny of 

the nuclides in Tables 6-6 and 6-7. The activities of the progeny radionuclides at 5 years after 

separation were calculated using the Radiological Toolbox 3.0.0. The photon intensities and energies 

emitted by the radionuclides were obtained from Bé et al. [2004, Volume 2 - A] and International 

Commission on Radiological Protection (ICRP) Publication 107 [ICRP 2008]. Bé et al. [2004, 

Volume 2 - A] is noted in the source definition section of the MCNP6.2 input files as "CEA". 

Neutron Source Calculations

The neutron source term was calculated using the SOURCES 4C computer code. The volumetric 

source considered for these calculations included neutrons emitted from within the volume of the 

source region by spontaneous fission and by (alpha,n) interactions.
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 39 of 56

Input to SOURCES 4C included the desired energy structure of the neutron spectrum, the number 

density of the actinide isotopes, and the fraction of the (alpha,n) target nuclides to the total number 

density. Neutron spectra were calculated in 760 groups with a minimum energy of 0 MeV and a 

maximum energy of 4.49 MeV. SOURCES 4C reports that 240Pu produces about 73% of all 

spontaneous fission and (alpha,n) neutrons that form the source term.

Carbon-13 was the only target isotope considered for calculations of (alpha,n) neutrons because the 

atom fraction of 13C exceeded the atom fractions of other impurity isotopes by about a factor of 100.

6.2.3.2.3 Dose Equivalent Calculations

Fluence to Dose Conversion Coefficients

MCNP6.2 was used to calculate the fluence rates of neutrons and photons that entered volume 

elements that represented dosimeters [ORAUT 2019b]. Two dosimeters were implemented in the 

MCNP6.2 input file, one at 30.48 cm from the center of the fuel pellet and one at 100 cm. The pellet 

and the dosimeter were assumed to be positioned 24 cm above the floor of the glovebox.

Conversion coefficients were used to translate the fluence rates to dose equivalent rates. The 

conversion coefficients were included in the MCNP6.2 input file and the conversion from fluence to 

dose equivalent was performed by MCNP6.2.

The selected neutron conversion coefficients are from Table A.42 of ICRP Publication 74 [ICRP 

1996]. The photon data were derived using conversion coefficients in Tables A.1, A.21, and A.24 of 

ICRP [1996].

Tallies

Photon exposures were divided into three energy bins (< 30 keV, 30- to 250-keV, and >250 keV). 

Neutrons were divided into five energy bins (<0.01 MeV, 0.01 to 0.1 MeV, 0.1 to 2 MeV, 2 to 20 MeV, 

and >20 MeV). For both neutrons and photons, the upper energy bins were divided in two to help 

elucidate the energy spectra of the radiations especially to determine if the tally energies exceeded 

the energy of the DCFs.

The tallies were accumulated into two air volumes that represented dosimeters. The air volumes were 

5.08 cm × 5.08 cm × 0.2 cm, and the centers were located 30.48 cm (1 ft) and 100 cm from the center 

of the fuel pellet.

6.2.3.2.4 Simulation Results

Dose rates were calculated at 1 ft (30.48 cm) and 1 m from the center of a single pellet [ORAUT 

2018b]. The dose rates from a single pellet were then scaled upward to account for the maximum 

amount of plutonium allowed to be processed in any batch.

The potential dose for each job category is based on the following assumption, consistent with the 

Battelle-TBD-6000 [NIOSH 2011]. Table 6-8 lists external doses.

• Operator basis. 50% of the workday was spent at 1 ft (30.48 cm) from the fuel object 

containing 525 g of pellets (i.e., 100 g of plutonium).

• Laborer basis. 50% of the workday was spent at 1 m from the fuel object containing 525 g of 

pellets (i.e., 100 g of plutonium).

• Supervisor basis. 50% of the Laborer exposure rate [NIOSH 2011].
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 40 of 56

 

• Clerk basis. 10% of the Supervisor exposure rate [NIOSH 2011]. 

Table 6-8. External dose from second 

operational period for plutonium (rem/yr). 

Category Penetrating Neutron

Operator 6.303 0.154

General laborer 0.590 0.017

Supervisor 0.295 0.008

Clerk 0.029 0.001

For the Operator, the penetrating dose should be applied as 0.16% <30-keV, 91.35% 30- to 250-keV, 

and 8.49% >250-keV photons. For the Laborer, Supervisor, and Clerk, the penetrating dose should be 

applied as 0.05% <30 keV, 91.68% 30- to 250-keV, and 8.27% >250-keV photons. 

For the Operator, the neutron dose should be applied as 0.02% <0.01-MeV, 0.21% 0.01- to 0.1-MeV, 

43.59% 0.1- to 2 MeV, and 56.17% >2-MeV neutrons. For the Laborer, Supervisor, and Clerk, the 

penetrating dose should be applied as 0.13% <0.01-MeV, 0.44% 0.01- to 0.1-MeV, 47.09% 0.1- to 

2-MeV, and 52.33% >2-MeV neutrons. 

Photon and neutron doses are treated as constant distributions. All doses should be assessed using 

ambient dose equivalent (H*(10)) to organ dose equivalent (HT) values in accordance with OCAS-IG001 [NIOSH 2007]. All photon doses should be assigned as acute exposures, and all neutron doses 

should be assigned as chronic exposures. ICRP Publication 60 corrections factors [ICRP 1991] 

should be applied to the neutron doses in accordance with ORAUT-OTIB-0055, Technical Basis for 

Conversion from NCRP Report 38 Neutron Quality Factors to ICRP Publication 60 Radiation 

Weighting Factors for Respective IREP Input Neutron Energy Ranges [ORAUT 2006]. 

6.2.3.3 X-Ray Diffraction

Carborundum XRD Machines

XRD machines can have a range of sizes and configurations from bench-top units to standalone 

devices in a laboratory. The operator’s position during operation is variable depending on the 

configuration of the XRD machine.

A former Carborundum worker who [redacted] the XRD machine [ORAUT 2016] was asked about the 

configuration of the XRD machine. The worker stated it sat on the floor and was not moved because 

water was plumbed to it. People could walk through the room but generally, only the people who 

worked with one of the three analytical devices in the room occupied it. According to the worker, these 

people “knew not to stand around” [ORAUT 2016, p. 2]. This worker further stated that the XRD 

machine operated for about 40 minutes per sample and there were about 10 sample runs per day.

The interviewed worker also described some technical details of the XRD machine. It had a hood and 

a shield, and workers prepared the sample, placed it in the XRD machine (with the shutter closed), 

closed the shield over the assembly, and opened the shutter to irradiate the sample. Once the 

assembly was in place, the worker walked away for the duration (about 40 minutes) of the sample 

operation [ORAUT 2016, p. 2]. 

Hazard Associated with an XRD Machine

The greatest hazard from XRD machines is from external exposure to the primary beam. This can 

occur most commonly during alignment procedures in which the target must be aligned with the 

output port, the sample with the primary beam, and the detector or film holder with the reflected beam 

[Lubenau 1969]. The primary beam of Kα characteristic X-rays has a very small area, on the order of 

0.01 cm2 at the exit port [Rudman 1971, p. 82]. This primary beam is very intense with an exposure 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 41 of 56

rate in the hundreds of thousands of R/s [Thomas 1971, p. 145]. If the X-ray tube is energized during 

alignment, the operator’s fingers or hands can be exposed to the primary beam. Historically, these 

types of accidents are the major hazard from XRD machines [Thomas 1971, p. 145]. No evidence of 

these types of radiation accidents has been found for Carborundum operations. 

Other than exposure to the primary beam, an operator would be exposed to leakage, diffracted 

radiation, and scatter radiation from the sample and other components. Each of these has slightly

different properties, as discussed below.

Leakage from the tube housing is assumed to be minimal [de Castro 1986, p. 10]. 

The source of the low-energy X-rays striking the sample is the Kα characteristic X-rays from the tube

target materials, commonly copper or iron. There is evidence that Carborundum used an XRD unit 

with a copper target [Strasser 1963, p. 30; TCC 1966, p. 101]. The former XRD [redacted] at 

Carborundum stated that the XRD machine had a copper target [ORAUT 2016, p. 3]. The energy of

the Kα1 characteristic X-ray of copper is 8.1 keV [Lubenau 1969]. 

The diffracted radiation would be emitted from the sample with an energy of 8.1 keV in small

directional beams. Given that the interviewed worker stated that the XRD machine had a shield over

the entire assembly [ORAUT 2016, p. 2], it is assumed that most of the diffracted radiation would have 

been absorbed in the shield material.

Electrons accelerated through a potential difference of about 35 to 50 kV (typical of a copper target 

tube) produce a bremsstrahlung X-ray spectrum in addition to the characteristic X-rays of copper. The 

average energy of the bremsstrahlung photons is about 20 keV [ANSI 1971, p. 20]. The scatter

radiation emitted isotropically with an average energy of about 20 keV is assumed to be the major

exposure source to workers in the XRD laboratory. Air attenuation can be quite large at low energies

[Granlund 1971, p. 181], but is ignored in this work. 

Dose from Scattered X-Ray Beam 

Lubenau [1969] provides measurements of scatter from a 1966 survey of XRD units in Pennsylvania. 

Scatter measurements for three XRD units with copper targets ranged from 0.0005 to 0.002 R/hr at 

the table edge. These measurements are reported as maximum scatter values from the respective 

machines during operation. The highest scatter measurement of 0.002 R/hr was used as the starting 

point for dose assessment for Carborundum. Lubenau does not specify the measurement distance, so 

a 30-cm distance was assumed as a practical distance from an enclosure or barrier for making a 

measurement [NBS 1964 p. 9]. 

Measurement of low-energy X-rays (8- to 20-keV) can require correction because most ion chamber

survey instruments are calibrated at the much higher photon energy from 137Cs (662 keV). Lubenau 

[1969] used a Victoreen 440RF ion chamber when measuring scatter from XRD machines in 

Pennsylvania. Els [1971] provides an instrument correction factor of about 2.48 for a Victoreen 

440 RF ion chamber measuring 8-keV photons diffracted from a copper target. 

According to the XRD [redacted] [ORAUT 2016, p. 3], the run-time of the XRD machine was 40

minutes per sample and there were about 10 samples per day. In addition, the worker estimated a 

total of 4 to 5 minutes of exposure to each sample in the vicinity of the machine. Therefore, over the

course of 50 weeks, the total exposure time would be 208.3 hr/yr (5 min/sample × 10 samples/d ×

250 workdays/yr = 12,500 min/yr). This results in an annual exposure of 2.83 × 10-3 R/calendar day

(208.3 hr/yr × 0.002 R/hr × 2.48 low-energy correction factor = 1.033 R/yr). 
Document No. ORAUT-TKBS-0061 Revision No. 00 Effective Date: 04/23/2020 Page 42 of 56

Penetrating doses should be applied as a constant distribution, assuming 100% <30-keV photons 

using acute exposure rate, and exposure (R)-to-organ (HT) DCF values in accordance with OCAS-IG001 [NIOSH 2007].

Based on the level of potential exposure, XRD operators should be compared to the Battelle-TBD6000 Laborer exposure scenario [NIOSH 2011].

6.2.4 Second Residual Period, 1968 to 1992

Residual surface contamination and air submersion DCFs from uranium are based on Battelle-TBD6000 [NIOSH 2011]. The Battelle-TBD-6000 [NIOSH 2011] surface contamination and air submersion 

DCFs in Section 5.2.4 were used to calculate the initial residual external dose exposure rates.

The initial surface and airborne contamination levels for the start of the first residual period were 

determined to be 2.87 × 104 dpm/m2 and 2.87 × 10-1 dpm/m3, respectively. This results in an initial 

exposure rate of 2.26 × 10-5 R/yr penetrating and 2.19 × 10-3 R/yr nonpenetrating. These doses will 

not be used because the 1968 dose rates for exposure in the centerless grinding work area in Table 

6-3 are higher, therefore would always be more favorable.

7.0 ATTRIBUTIONS AND ANNOTATIONS

All information requiring identification was addressed via references integrated into the reference 

section of this document.
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GLOSSARY

alpha radiation

Positively charged particle emitted from the nuclei of some radioactive elements. An alpha 

particle consists of two neutrons and two protons (a helium nucleus) and has an electrostatic 

charge of +2.

beta radiation

Charged particle emitted from some radioactive elements with a mass equal to 1/1,837 that of 

a proton. A negatively charged beta particle is identical to an electron. A positively charged 

beta particle is a positron.

depleted uranium

Uranium with a percentage of 235U lower than the 0.7% found in natural uranium.

dose

In general, the specific amount of energy from ionizing radiation that is absorbed per unit of 

mass. Effective and equivalent doses are in units of rem or sievert; other types of dose are in 

units of rad, rep, or grays.

dose conversion factor (DCF)

Multiplier for conversion of potential dose to the personal dose equivalent to the organ of 

interest (e.g., liver or colon). In relation to radiography, ratio of dose equivalent in tissue or 

organ to entrance kerma in air at the surface of the person being radiographed.

dose reconstruction

Process of analyzing the available information including evaluation of historical methods and 

data to estimate the dose a person could have received from one or more radiation exposures.

enrichment

Isotopic separation process that increases the percentage of a radionuclide in a given amount 

of material above natural levels. For uranium, enrichment increases the amount of 235U in 

relation to 238U. Along with the enriched uranium, this process results in uranium depleted in 

235U.

external dose

Dose received from radiation (e.g., photons, electrons, and neutrons) that originates outside 

the body including medical screening examinations.

exposure

(1) In general, the act of being exposed to ionizing radiation; see acute exposure and chronic 

exposure. (2) Measure of the ionization produced by X- and gamma-ray photons in air in units 

of roentgens.

glovebox

Enclosure with special rubber gloves through which an operator can handle radioactive or 

toxic material without risk of injury or contamination, normally operated at a slightly reduced 

pressure so that air leakage, if any, is inward.

half-life

Time in which half of a given quantity of a particular radionuclide disintegrates (decays) into 

another nuclear form. During one half-life, the number of atoms of a particular radionuclide 
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decreases by one half. Each radionuclide has a unique half-life ranging from millionths of a 

second to billions of years. 

internal dose

Dose received from radioactive material in the body (e.g., plutonium or uranium) that was 

inhaled, ingested, absorbed, or injected through a wound.

natural uranium

Uranium as found in nature, approximately 99.27% 238U, 0.72% 235U, and 0.0054% 234U by 

mass. The specific activity of this mixture is 2.6 × 107 becquerel per kilogram (0.7 microcuries 

per gram). See uranium. 

neutron (n)

Basic nucleic particle that is electrically neutral with mass slightly greater than that of a proton. 

There are neutrons in the nuclei of every atom heavier than normal hydrogen.

neutron radiation

Radiation that consists of free neutrons unattached to other subatomic particles emitted from a 

decaying radionuclide. Neutron radiation can cause further fission in fissionable material such 

as the chain reactions in nuclear reactors, and nonradioactive nuclides can become

radioactive by absorbing free neutrons. See neutron. 

nuclide

Stable or unstable isotope of any element. Nuclide relates to the atomic mass, which is the 

sum of the number of protons and neutrons in the nucleus of an atom. A radionuclide is an 

unstable nuclide.

photon radiation

Electromagnetic radiation that consists of quanta of energy (photons) from radiofrequency 

waves to gamma rays.

radiation

Subatomic particles and electromagnetic rays (photons) with kinetic energy that interact with 

matter through various mechanisms that involve energy transfer. 
 

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ATTACHMENT A 

RADIOLOGICAL CONTRACT WORK DURING THE SECOND OPERATIONAL PERIOD

Table A-1. Radiological contract work during the second operational period. 

Contract Years reported Type of work Radionuclides Amounts Comments Sources

AT-(40-1)-2558 05/1959-12/1960 Synthesis and fabrication of 

refractory U compounds: 

Three phases: 

(1) development of methods 

for synthesis of compounds; 

(2) fabrication of 

synthesized materials; and 

(3) determination of 

properties such as thermal 

conductivity, thermal 

expansion, hightemperature strength. 

Purpose: to develop 

methods to synthesize the 

materials UN, UC, and 

U3Si2 and methods of 

fabrication and to study 

various properties of the 

compounds for use as 

reactor fuel

UO2, U3O8, UN 

(powder), U3Si2

Request for 10 

pounds of U shot

[Taylor 1960] 

Make batches of UC 

ranging from about 

30 g to 6 lb [Taylor 

and McMurtry 

1961a] 

1,500-g batch of 

UN

1,200 g of UN was 

made [Taylor et al. 

1960a]

3-lb lot of UC 

prepared by the 

carbon reduction of 

UO2

100 g of U metal 

shot acid treated 

[Taylor et al. 

1960b] 

Part of the AEC Fuel 

Development Program

The goal was to develop 

refractory uranium materials 

possessing a sufficient 

advantage over UO2. 

Initial contract period was 

05/13/59 through 11/01/60.

No work done during 

May/June for facility 

improvements.

Carborundum had to 

replace a glovebox that was 

being used for some of the 

uranium work on this 

contract [Taylor et al. 

1960b]. 

Summary Report

[Taylor and McMurtry 

1961a] 

Fourth Quarterly 

Report

[Taylor et al. 1960c] 

Fifth quarterly report

[Taylor and McMurtry 

1961b] 

Monthly report

[Taylor et al. 1960a] 

Report 8

[Taylor et al. 1960b] 

Report 10

[Taylor and McMurtry 

1960a] 

Report 11

[Taylor and McMurtry 

1960c]

AT-(40-1)-2558 03/01/1961–

05/31/1961

Synthesis and fabrication of 

refractory U compounds

Sintering of U monocarbide

Depleted UO2; 

Thermax 

Thermatomic 

Carbon

453.6 g of UO2; 

60.5 g of carbon 

for each synthesis 

experiment

Purpose of work: develop 

refractory U materials 

possessing sufficient 

advantages over UO2 to 

warrant their use as reactor 

fuels. The UC was a 

powder. 

Depleted UO2 from ORNL; 

Thermax Thermatomic 

Carbon from R.T. Vanderbilt 

Co.

Two modifications were 

made to this contract to go 

beyond 12/60.

First Quarterly Report

[Taylor and McMurtry 

1961b] 
ATTACHMENT A 

RADIOLOGICAL CONTRACT WORK DURING THE SECOND OPERATIONAL PERIOD (continued)

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Contract Years reported Type of work Radionuclides Amounts Comments Sources

AT(30-1)-2303 06/06/1960 Fabrication of plutonium 

carbide pellets using some 

of the following methods:

ball milling, chemical 

analyses, crushing, cold 

pressing, sintering, grinding 

pellets

PuO2, UO2 3 kg of Pu over 

3 yr; the first and 

only shipment in 

1960 of 500 g of 

Pu from Hanford

Carbide Fuel Development.

Report states that if there is 

any external radiation 

exposure it will be to the 

hands. All Pu compounds 

will be handled on a 

containment basis.

Maximum amount of 

contained Pu will not 

exceed 600 g. No more than 

200 g of Pu shall be in 

process.

Feasibility Report

[Werner 1960] 

AT(30-1)-2303 02/01/1961–

04/30/1961

Fuel fabrication and 

evaluation: explore various 

methods of fuel preparation 

and fabrication into 

cylindrical pellets, beginning 

with powders and evaluate 

pellet density 

measurements

Pu, Pu+U-235,

PuC-UC, UO2

Synthesis of PuC 

from PuO2.

Seven batches of 

PuC made by 

mixing PuO2 and 

carbon then 

furnacing at 

differing 

temperatures and 

hold times

The Pu facility started 

operations in March 1961. 

Prior to 1961, the equipment 

was tested by work with UC.

Six reports are listed in 

covering 10/15/59 to 

2/28/61 [Strasser and Taylor 

1961]; these reports are 

currently unavailable.

Progress Report

[Strasser and Taylor 

1961]

AT(30-1)-3118 02/06/1961–

12/06/1963

Determine out-of-pile 

properties of mixed UPu

carbides to determine the 

properties of (UPu)C

Pu, U

Materials produced. 

80% UC-20% PuC 

solid solutions

Four 100-g 

synthesis batches 

prepared from 

UO2, PuO2, 

(UPu)C 

550-g total of UO2, 

PuO2 and carbon 

powder 

synthesized in 70- 

to 100-g batches

Prepared fuel samples. This 

program was closely 

coordinated with the 

Carbide Fuel Development 

program (AT30-1)-2899.

Final Report

[Stahl et al. 1963]
ATTACHMENT A 

RADIOLOGICAL CONTRACT WORK DURING THE SECOND OPERATIONAL PERIOD (continued)

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Contract Years reported Type of work Radionuclides Amounts Comments Sources

AT(30-1)-2899 05/1959-

10/15/1965

UNC: conceptual design, 

fuel evaluation, and fuel 

irradiation

Carborundum: fuel 

fabrication

UC, PuC

Investigate mixed 

carbides at 20 wt%

PuC, except 

property 

measurements 

which were made at 

5 w/o PuC fuel.

400 g of (U0.95 

Pu.0.5)C0.98 powder

synthesized for 

fabrication 

(70 pellets 

fabricated)

The Carbide Fuel 

Development Program was 

concerned with the 

technology of the entire UCPuC fuel cycle. The major 

goals were to produce 

(UPu)C and obtain data on 

its irradiation behavior for 

long burnups and at highpower generation rates. 

Other areas of the fuel cycle 

were explored to discover 

possible problems.

Program initiated in May 

1959; continued for 4.5 yr.

Final Report 

[Strasser and Stahl 

1965]

Six reports were 

published under this 

contract, Phases I-VI 

AT(30-1)-2899 09/15/1961–

12/31/1961

Explore methods for 

preparation of fuel from 

powders and its fabrication 

into cylindrical pellets, 

evaluate pellets by density 

measurement, chemical 

analysis, X-ray diffraction, 

hardness

UC-PuC

Synthesize powder

from oxides and 

carbons

Produce 

(U0.8Pu0.2)C0.95

NOTE: Comment in report 

says Pu facilities continued 

satisfactory operation at 

zero contamination levels. 

NOTE: Pu is lost during 

synthesis or sintering and a 

small amount of Pu being 

lost during annealing.

[Strasser and Taylor 

1962b] 

AT(30-1)-2899 01/01/1962–

03/31/1962

Fuel fabrication for AEC 

Fuel Cycle Development 

Program concerned with 

entire UC-PuC fuel cycle

Pu, U

UC-PuC pellets 

Sintering 

experiments with 

(U0.8Pu0.2)C0.95

Carbide Fuel Development, 

part of AEC Fuel Cycle 

Development Program.

Fuel made of UC and PuC 

had a potential of reducing 

fuel-cycle cost of existing 

fast-breeder reactors.

Progress Report

[Strasser and Taylor

1962b] 
ATTACHMENT A

RADIOLOGICAL CONTRACT WORK DURING THE SECOND OPERATIONAL PERIOD (continued)

Document No. ORAUT-TKBS-0061 Revision No. 0

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Contract Years reported Type of work Radionuclides Amounts Comments Sources

AT(30-1)-2899 04/01/1962–

06/30/1962

Fabrication of the UC-PuC 

irradiation tests

UC, PuC, UC-PuC 

pellets

Synthesize powder 

required for the NU

Reaction to 760-g

batch of PuO2-

UO2-C yielded 

~580 g of single 

phase 

(U0.2Pu0.2)C0.95

solid solution

There are 10 previous 

reports listed in this 

progress report.

Progress Report

[Strasser and Taylor 

1962c]

AT(30-1)-2899 09/15/1961–

09/30/1962

Conceptual design, fuel 

evaluation, and fuel 

irradiation

Powder containing 

NU, EU, Pu

760-g batch of 

PuO2-UO2-C 

yielded ~580 g of 

(U0.8Pu0.2)C0.95

200 g of 

(U0.8Pu0.2)C0.95 

powder produced 

in 40-g lots

Each specimen 

contained 16 fuel 

pellets

Carbide Fuel Development, 

this project is sponsored by 

the AEC Division of Reactor 

Development

Goal was to produce UCPuC to obtain data on 

irradiation behavior for long 

burnups and at high-power 

generation rates.

Goal was to develop 

method for preparation of 

high density pellets for 

irradiation studies 

Experiments were run with 

both NU and EU.

11 previous reports listed.

Phase IV Report

[Strasser and Taylor 

1963b]

AT(30-1)-2899 10/01/1962–

03/31/1963

Production of (UPu)C and 

collection of data on its 

irradiation behavior for long 

burnups and at high-power 

generation rates

(UPu)C Synthesis of about 

400 g of 

(U0.95Pu0.05)C0.98

50-g reaction mixes of 

PuO2, UO2 were blended

and cold pressed. There 

were 8 synthesis 

experiments.

Progress Report

[Strasser and Taylor 

1963a]

12 NDA and UNC 

progress reports listed 

before this report from 

10/15/1959-

03/31/1963
ATTACHMENT A 

RADIOLOGICAL CONTRACT WORK DURING THE SECOND OPERATIONAL PERIOD (continued)

Document No. ORAUT-TKBS-0061 Revision No. 0

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Contract Years reported Type of work Radionuclides Amounts Comments Sources

AT(30-1)-3254 02/06/1962-

10/31/1962

Determine out-of-pile 

properties of mixed UPu

carbides

Carborundum: prepare the 

fuel samples

Powder fabrication initiated 

under AT(30-1)-2889 

continues

(UPu)C

80% UC-20% PuC

Sintering 

experiments with 

(U0.8Pu0.2)C0.95

This program was closely 

coordinated with the 

Carbide Fuel Development 

program. The studies were 

a continuation of work 

performed under AT(30-1)-

2899. 

8 previous reports listed

Progress Report

[Strasser et al. 1963]

AT(30-1)-3305 02/01/1964-

10/30/1965

Study of UPu monoxides. 

UPu monoxide 

compositions synthesized 

by carbon and U reduction 

methods

U, Pu

Depleted UO2, 

PuO2, UHx, UC, UN

Started with UO2-

PuO2 mixtures to 

synthesize UPu

monoxide type 

materials

Two synthesis routes: 

(1) reduction of mixed PuO2

and UO2 with carbon; 

(2) reduction of mixed 

dioxides with U metal: 

carried out in helium and 

vacuum at temps from 

1450-1900 0C.

Previous progress in 

reports: UNC: 5096, 5102, 

5117, 5132, 5138, covering 

02/01/1964–09/30/1965.

Final Summary Report

[Forbes et al. 1966]

AT(30-1)-3305 07/01/1965–

09/30/1965

Study of UPu monoxides Materials containing 

as high as 85 w/o of 

a (UPu)(OC) 

composition

Synthesis of 

(U0.8Pu02)C 

Related reports: 

AT(30-1)3254, 02/06/1962-

10/31/1962 (see above). 

Quarterly Progress 

Report

[Forbes et al.1965]

AT(30-1)-3713 09/01/1966–

11/30/1966

Part of the AEC Fuel Cycle 

Development Program

Studies of the preparation of 

mixed carbide fuel using 

coprecipitation and 

synthesis of (UPu)C

X-ray analysis

U as UO2; Pu

Concentration of the 

U or UPu in the 

nitrate solutions was 

~0.15 g/mL

(U0.8Pu0.2)C Object is to extend the 

technology to the 

preparation of (UPu)C fuels. 

Uranyl nitrate and Pu nitrate 

solutions were mixed to 

yield 4/1 ratio of U to Pu.

Quarterly Progress 

Report No. 2

[McMurtry and Taylor

1966]

AT(30-1)-3713 11/23/1966–

02/28/1967

Part of the AEC Fuel Cycle 

Development Program

Study of synthesis (UPu)C 

compounds using

coprecipitation of carbon 

and metal-bearing materials 

from a common solvent

(UPu)C Started with 

(U0.8Pu0.2)C 

Object is to extend the 

technology to the 

preparation of (UPu)C fuels. 

Final Report

May 23, 1966-

February 28, 1967

[McMurtry 1967]