ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller & Associates I MJW Corporation

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Document Title:

Energy Technology Engineering Center –

Site Description

Document Number: ORAUT-TKBS-0038-2

Revision: 00

Effective Date: 02/02/2006

Type of Document: TBD

Supersedes: None

Subject Expert: Samuel T. Chu

Document Owner

Approval: Signature on File Approval Date: 01/31/2006

Melton H. Chew, TBD Team Leader

Approval: Signature on File Approval Date: 01/31/2006

Judson L. Kenoyer, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 01/31/2006

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 02/02/2006

James W. Neton, Associate Director for Science

 New Total Rewrite Revision Page Change

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

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION. 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 2 of 47

PUBLICATION RECORD 

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

02/02/2006 00 New technical basis document for Energy Technology Engineering 

Center - Site Description. First approved issue. Training required: 

As determined by the Task Manager. Initiated by Melton H. Chew.
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 3 of 47

TABLE OF CONTENTS 

SECTION TITLE PAGE

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

2.1 Introduction .............................................................................................................................. 7

2.2 Site Description and General Information ................................................................................. 8

 2.2.1 Santa Susana Field Laboratory ..................................................................................... 9

 2.2.1.1 Development and Testing of Nuclear Reactors ............................................... 13

 2.2.1.1.1 Homogeneous Water Boiler Reactors ............................................ 13

 2.2.1.1.2 Sodium-Cooled Graphite-Moderated Reactors ............................... 15

 2.2.1.1.3 Systems for Nuclear Auxiliary Power Reactors ............................... 17

 2.2.1.2 Critical Test Facilities ...................................................................................... 19

 2.2.1.2.1 SNAP Development Test Facilities ................................................. 19

 2.2.1.2.2 Civilian Nuclear Power Test Facilities ............................................. 20

 2.2.1.3 Nuclear Support Operations ............................................................................ 21

 2.2.1.3.1 Reactor Fuel Manufacturing ........................................................... 22

 2.2.1.3.2 Disassembly and Examination of Reactors and Used 

 Reactor Fuel Assemblies ............................................................... 23

 2.2.1.3.3 Fabrication, Use, and Storage of Radioactive Sources ................... 24

 2.2.1.3.4 Preparation of Radioactive Material for Disposal ............................ 24

 2.2.1.3.5 Research on Reprocessing Used Reactor Fuel .............................. 25

 2.2.1.3.6 Operation of Particle Accelerators .................................................. 26

 2.2.1.3.7 Research Using Radioisotopes ...................................................... 26

 2.2.1.3.8 Miscellaneous Operations .............................................................. 26

 2.2.2 Other Relevant Facilities ............................................................................................. 27

 2.2.2.1 Downey ........................................................................................................... 27

 2.2.2.2 Canoga Park ................................................................................................... 28

 2.2.2.3 DeSoto ............................................................................................................ 28

2.3 Isotopes of Concern ............................................................................................................... 30

2.4 Magnitude of Site Activity ....................................................................................................... 30

 2.4.1 Operation of Nuclear Reactors ................................................................................... 39

 2.4.2 Operation of Criticality Test Facilities .......................................................................... 40

 2.4.3 Manufacture of Reactor Fuel Assemblies ................................................................... 43

 2.4.4 Disassembly and Examination of Reactors and Used Reactor Fuel 

 Assemblies ................................................................................................................. 43

 2.4.5 Fabrication, Use, and Storage of Radioactive Sources ............................................... 43

 2.4.6 Preparation of Radioactive Material for Disposal ........................................................ 43

 2.4.7 Research on Reprocessing Used Reactor Fuel .......................................................... 44

 2.4.8 Operation of Particle Accelerators .............................................................................. 44

 2.4.9 Research Using Radioisotopes ................................................................................... 44

2.5 Major Incidents ....................................................................................................................... 44

2.6 Radiological Access Controls ................................................................................................. 44

References ........................................................................................................................................ 46

Glossary ............................................................................................................................................ 47
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LIST OF TABLES 

TABLE TITLE PAGE

2-1 Site information of nuclear research operations conducted at Area IV.................................... 12

2-2 NMDF operational history....................................................................................................... 22

2-3 Area information and parameters of nuclear operations ......................................................... 31

2-4 Magnitude of nuclear operations ............................................................................................ 34

2-5 Reactor operations ................................................................................................................. 41

2-6 Major incidents ....................................................................................................................... 45

LIST OF FIGURES 

FIGURE TITLE PAGE

2-1 Aerial view of Area IV ............................................................................................................... 8

2-2 SSFL and Area IV location map ............................................................................................. 10

2-3 Summary of primary Area IV programs and operations .......................................................... 11

2-4 Nuclear activities sites at Area IV ........................................................................................... 14

2-5 SRE plot plan ......................................................................................................................... 16

2-6 Radioactivity from reactors ..................................................................................................... 42
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ACRONYMS AND ABBREVIATIONS 

AEC U.S. Atomic Energy Commission 

AERD Atomic Energy Research Department 

AETR Advanced Epithermal Thorium Reactor 

AI Atomics International 

AMAD activity median aerodynamic diameter 

ATR Advanced Test Reactor 

Ci curie 

D&D decontamination and decommissioning 

DOE U.S. Department of Energy 

EBR-I Experimental Breeder Reactor No. 1 

EBR-II Experimental Breeder Reactor No. 2 

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000 

ETEC Energy Technology Engineering Center 

F fast (solubility type) 

ft foot 

g gram 

gal gallon 

HEPA high-efficiency particulate air 

HERF High Energy Rate Forging 

HMRFSR Heavy Metal Reflected Fast Spectrum Reactor 

hr hour

ISF Interim Storage Facility 

KEWB Kinetics Experiment Water Boiler 

kWt thermal kilowatt 

kWth thermal kilowatt-hour

lb pound

LLRW low-level radioactive waste 

LMEC Liquid Metal Engineering Center 

LMFBR Liquid Metal Fast-Breeder Reactor 

LMIC Liquid Metal Information Center 

LMR liquid metal reactor 

M moderate (solubility type) 

mCi millicurie 

MeV megaelectron-volt, 1 million electron-volts 

MPC maximum permissible concentration 

mrem millirem 

MW megawatt 

MWd megawatt-day

MWthr thermal megawatt 
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NAA North American Aviation 

NIOSH National Institute for Occupational Safety and Health 

NMDF Nuclear Materials Development Facility 

NRC U.S. Nuclear Regulatory Commission 

OMR Organic Moderated Reactor 

OMRE Organic Moderated Reactor Experiment 

pCi picocurie 

R&D research and development 

RMDF Radioactive Material Disposal Facility 

RMHF Radiation Materials Handling Facility 

S slow (solubility type) 

S10FS3 SNAP 10 Flight Simulation Reactor 

S2DR SNAP 2 Development Reactor 

S2ER SNAP 2 Experimental Reactor 

S8DR SNAP 8 Development Reactor 

S8ER SNAP 8 Experimental Reactor 

SER SNAP Experimental Reactor 

SGR Sodium Graphite Reactor 

SNAP Systems for Nuclear Auxiliary Power 

SNAPTRAN SNAP Transient 

SRE Sodium Reactor Experiment 

SSFL Santa Susana Field Laboratory 

STIR Shield Test and Irradiation Reactor

STR Shield Test Reactor 

TRU transuranic 

TRUMP-S Transuranic Management by Pyropartitioning-Separation 

U.S.C. United States Code 

W watt 

Wt thermal watt 

WBNS Water Boiler Neutron Source 

yr year 

μm micrometer 

μrem microrem 

§ section 
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2.1 INTRODUCTION 

Technical basis documents and site profile documents are general working documents that provide 

guidance concerning the preparation of dose reconstructions at particular sites or categories of sites. 

They will be revised in the event additional relevant information is obtained about the affected site(s). 

These documents may be used to assist the National Institute for Occupational Safety and Health 

(NIOSH) in the completion of the individual work required for each dose reconstruction. 

In this document the word “facility” is used as a general term for an area, building, or group of 

buildings that served a specific purpose at a site. It does not necessarily connote an “atomic weapons 

employer facility” or a “Department of Energy [DOE] facility” as defined in the Energy Employees 

Occupational Illness Compensation Program Act [EEOICPA; 42 U.S.C. § 7384l(5) and (12)]. 

EEOICPA defines a DOE facility as “any building, structure, or premise, including the grounds upon 

which such building, structure, or premise is located ... in which operations are, or have been, 

conducted by, or on behalf of, the Department of Energy (except for buildings, structures, premises, 

grounds, or operations ... pertaining to the Naval Nuclear Propulsion Program)” [42 U.S.C. § 

7384l(12)]. Accordingly, except for the exclusion for the Naval Nuclear Propulsion Program noted 

above, any facility that performs or performed DOE operations of any nature whatsoever is a DOE 

facility encompassed by EEOICPA. 

For employees of DOE or its contractors with cancer, the DOE facility definition only determines 

eligibility for a dose reconstruction, which is a prerequisite to a compensation decision (except for 

members of the Special Exposure Cohort). The compensation decision for cancer claimants is based 

on a section of the statute entitled “Exposure in the Performance of Duty.” That provision [42 U.S.C. § 

7384n(b)] says that an individual with cancer “shall be determined to have sustained that cancer in the 

performance of duty for purposes of the compensation program if, and only if, the cancer ... was at 

least as likely as not related to employment at the facility [where the employee worked], as 

determined in accordance with the [probability of causation] guidelines established under subsection § 

(c) ...” [42 U.S.C. § 7384n(b)]. Neither the statute nor the probability of causation guidelines (nor the 

dose reconstruction regulation) define “performance of duty” for DOE employees with a covered 

cancer or restrict the “duty” to nuclear weapons work. 

As noted above, the statute includes a definition of a DOE facility that excludes “buildings, structures, 

premises, grounds, or operations covered by Executive Order No. 12344, dated February 1, 1982 (42 

U.S.C. 7158 note), pertaining to the Naval Nuclear Propulsion Program” [42 U.S.C. § 7384l(12)]. 

While this definition contains an exclusion with respect to the Naval Nuclear Propulsion Program, the 

section of EEOICPA that deals with the compensation decision for covered employees with cancer 

[i.e., 42 U.S.C. § 7384n(b), entitled “Exposure in the Performance of Duty”] does not contain such an 

exclusion. Therefore, the statute requires NIOSH to include all radiation exposures in its dose 

reconstructions for employees at DOE facilities, including radiation exposures related to the Naval 

Nuclear Propulsion Program. As a result, all internal and external dosimetry results are considered 

valid for use in dose reconstruction. No efforts are made to determine the eligibility of any fraction of 

total measured exposure for inclusion in dose reconstruction. 

This document describes the features and history of the Energy Technology Engineering Center 

(ETEC), including the site areas or buildings, site processes, periods of operation, radionuclides of 

concern, and other information pertinent to dose reconstruction. The U.S. Atomic Energy 

Commission (AEC) established ETEC in 1966. The Center has provided management, engineering, 

testing, consultation, and project monitoring services for a wide range of energy programs. 
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ETEC conducted a broad range of energy-related research, testing, and development projects that 

included component testing for the U.S. liquid metal reactor (LMR) program. Liquid metal test 

facilities were maintained and operated for evaluating components such as heat exchangers, steam 

generators, pumps, valves, piping, vessels, and instrumentation. In addition to the reactor component 

testing program, ETEC provided engineering support, technical management, and monitoring for a 

number of DOE solar, conservation, geothermal, and fusion energy programs. ETEC facility and 

capability users other than DOE have included the U.S. Department of Defense, the U.S. Nuclear 

Regulatory Commission (NRC), and the Electric Power Research Institute. 

2.2 SITE DESCRIPTION AND GENERAL INFORMATION

This section describes the Energy Technology Engineering Center (ETEC), including the site areas or 

buildings, site processes and their magnitude, periods of operation, and other information pertinent to 

dose reconstruction. Figure 2-1 shows an aerial view of ETEC. 

Figure 2-1. Aerial view of Area IV. 

The Energy Technology Engineering Center (ETEC), established by the Atomic Energy Commission 

in 1966, provides management, engineering, testing, consultation, and project monitoring services for 

a wide range of DOE programs. ETEC is known as Area IV that consists of government-owned 

buildings within the Santa Susana Field Laboratory (SSFL) currently operated by the Boeing 

Company. Section 2.2.1 describes the facilities of ETEC in Area IV of the Santa Susana Field 

Laboratory (SSFL). 

In addition to the facilities in SSFL that supported DOE, Rockwell International, under other contracts 

or grants to DOE or its predecessor agencies, had performed DOE activities at the Downey, Canoga 
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Park, and DeSoto facilities. These three facilities are all located outside the boundaries of the SSFL 

site. Since Rockwell International workers could have worked at any or all of these sites as well as at 

Area IV, Section 2.2.2 of this site description describes them. 

2.2.1 Santa Susana Field Laboratory

The Santa Susana Field Laboratory (SSFL), consisting of a total of 2850 acres is located in the Simi 

Hills of Ventura County, approximately 30 miles northwest of downtown Los Angeles, California. 

SSFL is divided into four administrative and operational portions based on ownership and operations. 

DOE operations are conducted in Rockwell International-owned and DOE-owned facilities on a 290-

acre westernmost administrative and operational portion designated as Area IV. Figure 2-2 shows its 

location. 

Following World War II, the potential of atomic energy captured the interest of the United States 

Government and many companies. This created the need for nuclear Research & Development 

(R&D) facilities. The SSFL was initially established by North American Aviation (NAA) in 1947 to 

meet the requirements for a field test laboratory to static-fire large rocket engines, but it also met the 

NAA’s need for a nuclear research facility. Area IV was established at the SSFL in 1953 as a nuclear 

research and development facility. Since then, the SSFL has housed both nuclear development and 

rocket development groups, although in distinct and separate locations. The rocket development 

group conducted operations in the SSFL’s Area I, II, and III. The Atomic Energy Research 

Development (AERD) conducted operations in the SSFL’s Area IV. In December 1955, these two 

NAA groups were transformed into separate divisions: Atomic International (AI) and Rocketdyne. 

Two distinct groups of AI were housed in Area IV to support DOE. The AI focused on development of 

civilian nuclear power, and the Liquid Metal Engineering Center (LMEC) was a center for research 

and testing of non-nuclear components related to liquid metals. Nuclear R&D activities in Area IV 

increased rapidly from 1953 into the late 1960s, then declined. AI was merged into Rocketdyne in 

1984 as a result of this decline. 

The LMEC was created in 1966 as a government-owned and contractor-operated organization to 

provide development and non-nuclear testing of LMR components and to establish the Liquid Metal 

Information Center (LMIC) for the AEC’s Liquid Metal Fast-Breeder Reactor (LMFBR) program. The 

LMEC was renamed ETEC in 1978 to reflect the DOE’s desire to broaden its mission beyond the 

LMFBR program. 

Several corporate mergers and organizational changes occurred over the years. In 1967 NAA 

merged with Rockwell Standard to become North American Rockwell. In 1973 the corporate name 

changed to Rockwell International (RI). Rockwell International with AI and Rocketdyne continued to 

exist as independent divisions until 1984 when AI was absorbed by the Rocketdyne division. The 

Boeing Company purchased RI in 1996, and Rocketdyne is now a division of Boeing.

ETEC conducted a broad range of energy-related research, testing and development projects that 

included component testing for the U.S. liquid metal reactor program. Liquid metal test facilities were 

maintained and operated for evaluating components such as heat exchangers, steam generators, 

pumps, valves, piping, vessels and instrumentation. In addition to the reactor component testing 

program, ETEC provided engineering support, technical management and monitoring for a number of 

DOE solar, conservation, geothermal, and fusion energy programs. ETEC facility and capability users 

other than DOE include the Department of Defense, Nuclear Regulatory Commission, and Electric 

Power Research Institute. 
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Figure 2-2. SSFL and Area IV location map (Sapere and Boeing 2005). 

The phasing out of nuclear operations began during the mid-1960s. By 1988 all nuclear reactor 

operations in Area IV had ceased. Site cleanup and remediation has been ongoing since then. 

Nuclear support operations ended in 1996 with the exception of the Radioactive Materials Handling 

Facility (RMHF), a designated radiological facility that remains operational to provide chemical and 

radiological waste treatment and packaging for offsite disposal. 

Most nuclear research programs and operations ceased in 1988 and all non-nuclear research ended 

in 1998, although some support operations including the Fuel Storage Facility and the Radiation 

Instrument Calibration Laboratory did not cease until 1996. Beginning in the 1990s, activities in 

Area IV have focused on D&D and remediation. 

Before the remaining research activities ended in 1998, three primary types of operations were 

conducted at Area IV: 1) development and testing of nuclear reactors, 2) nuclear support operations, 

and 3) non-nuclear energy research and development. Figure 2-3 is a chronological representation of 

the individual programs (including their duration and corporate history) that supported the three 

primary types of nuclear research operations conducted in Area IV since its inception in 1953. Table 

2-1 lists the specific nuclear operations conducted in Area IV, the site(s) or building(s) where the 

operation took place, and the time period of operations. Figure 2-4 shows the location of the sites 

where nuclear research activities were carried out at the SSFL and indicates the decontamination 

status of these sites as of 1991. 
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Figure 2-3. Summary of primary Area IV programs and operations (Sapere and Boeing 2005). 
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Table 2-1. Site information of nuclear research operations conducted at Area IVa

Section Name Description

Period of 

operationsbFacility

Reactor operations

2.2.2.1 WBNS Reactor Water Boiler Neutron Source Reactor

4 Wthr

1952-1955 Downey Plant

2.2.2.2 L-47, L-77 Aqueous uranyl sulfate homogeneous 

reactors 10 Wthr

1954-1960 Canoga Park Plant 

Vanowen Building

2.2.2.3 L-77 Aqueous uranyl sulfate homogeneous 

reactor 10 Wthr

1960-1976 DeSoto Plant

Building 104

2.2.1.1.1 (1) KEWB Reactor Kinetics Experiment Water Boiler 

Reactor 1 kWthr

1956-1966 Building 4073

2.2.1.1.1 (2) WBNS or L-85 

Reactor

Water Boiler Neutron Source Reactor

3 kWthr

1956-1980 Building 4093

2.2.1.1.2 (1) SRE Reactor Sodium Reactor Experiment Reactor

20 MWthr

1957-1964 Building 4143

2.2.1.1.3 (1) SER SNAP Experimental Reactor

50 kWthr

1959-1960 Building 4010

2.2.1.1.3 (2) S8ER SNAP 8 Experimental Reactor

600 kWthr

1963-1965

2.2.1.1.3 (3) S2DR SNAP 2 Development Reactor

50 kWthr

1961-1962 Building 4024

2.2.1.1.3 (4) S10FS SNAP 10 Flight Simulation Reactor 

7 kWthr

1965-1966

2.2.1.2.1 (4) SNAP Transient 

Test Facility 

SNAP Transient Test Facility 1971

2.2.1.1.3 (5) STR Shield Test Reactor 50 kWthr 1961-1964 Building 4028

2.2.1.1.3 (6) STIR Shield Test and Irradiation Reactor

1 MWthr

1964-1972

2.2.1.1.3 (7) S8DR SNAP 8 Development Reactor

600 kWthr - 1 MWthr

1968-1969 Building 4059

2.2.1.2.1 (2) SNAP Critical 

Test Facility 

Second SNAP Critical Test Facility 1962-1968 Building 4012

HMRFSR 1970-1972

2.2.1.2.1 (1) SNAP Critical 

Test Facility

First SNAP Critical Test Facility 1957-1963 Building 4373

2.2.1.2.1 (3) SNAP Flight 

System Critical

Facility 

SNAP Flight System Critical

Facility 

1964-1965 Building 4019

2.2.1.2.2 (2) OMR Critical 

Facility

Organic Moderated Reactor

Low power critical experiment

1958-1967 Building 4009

2.2.1.2.2 (3) SGR Critical 

Facility

Sodium Graphite Reactor

Low power critical experiment

1958-1967

2.2.1.2.2 (4) AETR Test 

Facility

Advanced Epithermal Thorium Reactor 1960-1974 Building 4100

2.2.1.2.2 (5) Fast Critical 

Experiment 

Laboratory

Fast Critical Experiment Laboratory 

used to study different reactor core 

configurations

1961-1980

Nuclear Support Operations

2.2.2.3 Powder Room Advanced Test Reactor (ATR) fuel 

fabrication and supporting activities 

1959-1983 DeSoto Plant

Building 101 

2.2.2.3 Radiochemistry 

Laboratories 

Hot radiochemistry Laboratories 1959-1989 DeSoto Plant

Building 104 

2.2.1.3.1 (1) Engineering 

Test Building 

Reactor fuel manufacturing facility to 

support Sodium Reactor Experiment 

1954-1964 Building 4003 

2.2.1.3.5 (1) Hot Cave Hot cell for reprocessing used reactor 

fuel

1954-1964

2.2.1.3.4 (2) ISF Interim Storage Facility for SRE fuels 1958-1964 Building 4654 

2.2.1.3.1 (3) Uranium 

Carbide Fuel 

Pilot Plant

Uranium Carbide Fuel Manufacturing 

Pilot Plant

1964-1967 Building 4005

2.2.1.3.6 (1) Van de Graaff 

Accelerator 

Particle accelerator 1960-1964 Building 4030

2.2.1.3.2 (1) Hot Lab Hot Laboratory for disassembly and 

examination of used reactor fuel

1957-1988 Building 4020
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Table 2-1 (Continued). Site information of nuclear research operations conducted at 

Area IVa

Section Name Description

Period of 

operationsaFacility

Nuclear Support Operations (continued)

2.2.1.3.7 (2) Corrosion 

Testing 

Laboratory

Liquid Metals Component

Testing Facility

1962-1986 Building 4023

2.2.1.3.3 (1) Radioactive 

Measurement

Facility 

This facility for storage and use of 

radioactive sources for calibration of 

radiation instruments

1959-1974 Building 4029

2.2.1.3.1 (2) NMDF Nuclear Materials Development Facility 

for development work involving 

plutonium fuel manufacturing

1967-1979 Building 4055

2.2.1.3.1 (4)

2.2.1.3.7 (1)

Fuel Storage 

Facility 

Fuel Storage Facility is a vault built to 

provide storage for fissionable fuel 

material (EU & Pu)

1958-1993 Building 4064

2.2.1.3.4 (1) RMDF Radioactive Materials Disposal Facility 

was built for fuel storage and 

processing solid and liquid waste for 

disposal in conjunction with the SRE 

operation

1959-present Buildings 4021/4022

a. This table includes the nuclear research facilities in the off-site Downey, Canoga Park and DeSoto Plants for 

completeness. 

b. For reactors, refers to operation of the reactor rather than program duration dates provided in Figure 2-3. 

The specific operations and its associated facilities are summarized in the following sections: 

2.2.1.1 Development and Testing of Nuclear Reactors 

Between 1954 and 1980, several nuclear reactors were built, tested, and operated in Area IV. These 

included both nuclear reactors and critical test assemblies. Nuclear reactor programs focused on the 

development and operation of homogeneous water boiler-type reactors, sodium-cooled graphitemoderated reactors, and uranium-zirconium hydride reactors. 

2.2.1.1.1 Homogeneous Water Boiler Reactors 

The water boiler reactors were operated in Buildings 4073 and 4093. The water boiler reactors used 

a 93% enriched uranyl sulfate solution held in a critical configuration in a spherical vessel. Rather 

than actually boil, the neutron and gamma flux caused radiolytic decomposition of water into hydrogen 

and oxygen in the form of tiny bubbles, which gave the impression of boiling. Area IV contained two 

water boiler reactors. 

(1) Kinetics Experiment Water Boiler (KEWB), Building 4073. This reactor was located in Building 

4073 and operated from 1956 until 1966. This was the first nuclear reactor to be operated at the 

SSFL. It was a small research reactor using a water solution of uranyl sulfate as fuel. The reactor 

started up with a spherical tank core in July 1956, and later operated with the cylindrical tank core. 

The cores were enclosed in a cube of graphite approximately 5 ft on a side. The graphite cube, 

contained in an aluminum box, was installed in a specially designed concrete vault (Building 073) built 

underground. The reactor was used to study the dynamic behavior and inherent safety of 

homogeneous water boiler reactors. Most operations were at very low power (1 kWt or less), but the 

reactor was operated briefly at 50 kWt. The final use was as a neutron pulse test facility, for many 

different tests. It was shut down for the last time in November 1966. In 1975 the reactor was 

removed and disposed of, and the facility was decommissioned, decontaminated, released for 

unrestricted use, and demolished in 1975. 

Incidents: There were no incidents of any consequence with the KEWB. 
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Figure 2-4. Nuclear activities sites at Area IV (Oldenkamp and Mills 1991). 
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(2) Water Boiler Neutron Source (WBNS), Building 4093. This was a small low-power research 

reactor, initially named AE-6. In 1972 the reactor name was changed to L-85. The core was a 

solution of uranyl sulfate in a spherical tank surrounded by a graphite reflector. This reactor had a 

homogeneous solution core as did the KEWB, but it could operate at up to 2 kWt. It was used as a 

neutron source for many different tests and for reactor operator training. The reactor operated off and 

on for 24 years from November 1956 to February 1980. It was then shut down, removed, and 

disposed of, and the facility was decommissioned and decontaminated. The reactor facility was 

released for unrestricted use on April 8, 1987. 

Incidents: On March 25, 1959, one of the instruments that controlled the power of the AE-6 

malfunctioned and allowed the reactor to exceed the normal power level of 3 kWt and to approach 

4 kWt. As soon as the power level was recognized, the reactor was shut down by the operator. 

2.2.1.1.2 Sodium-Cooled Graphite-Moderated Reactors 

Figure 2-5 is a plan view of the Sodium Reactor Experiment (SRE) facility during its operating period. 

There were 12 structures on the site including the reactor building, office buildings, and support 

structures. Eight structures were directly involved in operations with radioactive materials: 

1. Reactor Building (Building 4143) 

2. Component Storage Building (Building 4041) 

3. Temporary Hot Waste Storage Building (Building 4686) 

4. Site Service Building (Building 4163) 

5. Cold Trap Vault (Building 4695) 

6. Liquid Radioactive Waste Vault (Building 4653) 

7. Interim Radioactive Waste Storage Area (Area 4654) 

8. Intermediate Contaminated Storage Area (Area 4689) 

(1) Sodium Reactor Experiment (SRE), Building 4143. The SRE started in Area IV in 1954 as part of 

an AEC program to develop a graphite-moderated sodium-cooled reactor for power application and to 

demonstrate the feasibility of such reactors as an energy source for power stations. 

The SRE reactor in Building 4143 was a 20-MW thermal reactor using slightly enriched uranium metal 

fuel in the initial core loading. The fuel was stainless-steel-clad rods with sodium bonding in the 

annulus between the fuel and cladding. The active core length was 6 ft. Heat generated in the 

reactor was transported by a primary sodium cooling system to a heat exchanger, and then by a 

secondary sodium system to a steam generator, which powered a steam turbine and generator 

provided by Southern California Edison Company. The SRE was the first civilian nuclear reactor in 

the United States to produce power for supply to a commercial power grid; it provided electricity to the 

City of Moorpark as part of the demonstration. Construction of the SRE reactor was completed in 

February 1957, and the ambient temperature subcritical experiment, without sodium in the core, was 

started on March 23, 1957. On April 25, 1957, the SRE was brought to criticality with 350°F sodium in 

the core. The reactor was brought to full power in early May 1958 and operated until February 1964. 

During this time, it generated 37,000 MWhr of electrical power in more than 27,000 operating hours. 

In 1959, the SRE reactor experienced a coolant failure described below. The reactor was shut down 

for repair on July 27, 1959, and restarted on September 5, 1960. The reactor then operated without 

further incident until 1964 when the DOE terminated the program. It was shut down for the last time 

on February 15, 1964, and maintained in a safe shutdown condition until September 1967. At that 

time, the sodium coolant was drained and the core was removed. These items were sent off the site 

for disposal, and the facility was then maintained in place until 1974. 
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Figure 2-5. SRE plot plan (Oldenkamp and Mills 1991). 
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D&D of the SRE began in 1974 and was complete in 1983. The work involved the removal of over 

136,000 ft3 of radioactive waste and of nearly 90% of the entire reactor-generated radioactivity from 

the SSFL. The final radiation survey was verified independently by a group from Argonne National 

Laboratory, and the site was released for unrestricted use in 1983. The building was used as a 

storage facility from 1983 until its demolition in 1999. 

Incidents: The reactor underwent an accidental partial blockage of sodium coolant in some reactor 

coolant channels in July 1959. This resulted in the partial melting of 13 of the reactor fuel assemblies 

and the release of some fission products that contaminated the reactor cooling system. All of the 

reactor safety systems functioned properly, and the reactor was safely shut down. The reactor fuel 

assemblies were removed, inspected, and stored at the Radioactive Materials Disposal Facility 

(RMDF). (They were later declad in the Hot Lab, and the fuel and cladding were shipped off the site.) 

A second fuel loading was inserted, and the test operations were continued. 

2.2.1.1.3 Systems for Nuclear Auxiliary Power Reactors 

The Systems for Nuclear Auxiliary Power (SNAP) program operated from 1956 to 1971 to support the 

development and testing of small reactors designed to provide power for research missions in space. 

The SNAP reactors were uranium-zirconium hydride reactors that used fully enriched (93%) uranium 

dispersed in fuel rods containing zirconium hydride. Seven SNAP reactors were tested and operated 

in Buildings 4010, 4024, 4028, and 4059. 

(1) SNAP Experimental Reactor (SER), Building 4010. Building 4010 was built in 1959 as a test 

facility for the SER, a uranium-zirconium hydride reactor in which fully enriched uranium was 

dispersed in fuel rods containing hydrogen at about the density of water. Also known as the SNAP 2 

Experimental Reactor (S2ER), the SER was a prototype for the basic SNAP reactor. Operated in 

Building 4010 at a power level of 50 kWthr, the reactor was used for power demonstration and 

endurance tests. The reactor was controlled by movable segments in a beryllium reflector sleeve and 

was shielded by lithium hydride. 

The SER operated from September 1959 to December 1960 when the reactor and the associated test 

equipment were removed, examined, and sent off the site for disposal. The facility was then modified 

to test the larger SNAP 8 Experimental Reactor (S8ER) described next. 

Incidents: There were no incidents of any consequence with the SER. 

(2) SNAP 8 Experimental Reactor (S8ER), Building 4010. This was a prototype SNAP 8 reactor, the 

first in a series of reactor tests to be performed to develop a flight-qualified SNAP 8 reactor. The 

SNAP 8 Experimental Reactor was a compact, 600-kWt reactor installed in Building 4010 after the 

removal of the SNAP SER in 1960. It was cooled by flowing NaK, a liquid alloy of sodium and 

potassium metals. The S8ER operated from May 1963 to April 1965 at its designed power level of 

600 kWthr. 

Following completion of the S8ER operations, the core and associated equipment were then 

removed, examined at the Hot Lab, and sent offsite for disposal. D&D of Building 4010 was 

completed in 1978. The building was demolished and removed. A total of 7,150 ft3 of radioactive 

waste was removed. 

Incidents: During operation of the S8ER some cracks developed in the cladding, which served to 

separate the zirconium-uranium alloy fuel from the NaK coolant. The cracks were the result of 

swelling in the fuel that stretched the cladding beyond its ductility limit. Some fission products diffused 
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out of the fuel and found their way into the flowing NaK through the cracks in the cladding. There was 

no melting of the fuel or cladding. The fission products were completely contained within the reactor 

system. 

(3) SNAP 2 Development Reactor (S2DR), Building 4024. This was a prototype of the SNAP 2 

reactor; it was tested at a nominal power level of 65 kWt without any power conversion system 

equipment. The reactor was tested in Vault 1 of the SNAP Environmental Test Facility. [Building 

4024 also contained the SNAP 10 Flight System 3 (S10FS3) reactor in a different vault, and the 

SNAP Transient (SNAPTRAN) Reactor criticality tests occurred in this building.] The S2DR operated 

from April 1961 to December 1962. 

Incidents: There were no incidents of any consequence with the S2DR. 

(4) SNAP 10 Flight Simulation Reactor (S10FS3), Building 4024. This was a SNAP 10A reactor used 

to test the reliability and performance of the reactors in space. Between January 1965 and March 

1966, the reactor operated continuously for 10,000 hr at 37 kWthr. It was collocated with S2DR in 

Building 4024, in the west cell of the building. 

Following completion of the S10FS3 operations, the reactor was removed from the building and sent 

off the site for disposal. The D&D activities for Building 4024 were completed in 1978. About 2000 ft3

of material was removed. Some activated concrete shielding remains in the vaults. At that time the 

nonvault portions of the building were declared suitable for release for unrestricted use. The test 

vaults remain restricted and have been in surveillance and maintenance mode since 1978. Additional 

decontamination and demolition is scheduled to occur in 2005. 

Incidents: There were no incidents of any consequence with the S10FS3 reactor. 

(5) Shield Test Reactor (STR), Building 4028. This reactor was used primarily to generate radiation 

fields for shielding tests of SNAP reactors. It operated from 1961 to 1964 with a power rating of 50 

kWt. The 50-kWt core was fueled with SNAP reactor fuel elements. It first went critical in December 

1962. In addition to shielding tests, tests were also done to study radiation damage to electronic 

systems, and to qualify reactor hardware for SNAP reactors. The reactor was installed in a tank of 

water in Building 4028. 

In 1964, the reactor was modified to raise the power rating to 1,000 kWt and renamed the Shield Test 

and Irradiation Reactor (STIR) described next. 

Incidents: There were no incidents of any consequence with the STR. 

(6) Shield Test and Irradiation Reactor (STIR), Building 4028. This was a rebuild of the STR to 

increase its power level for testing purposes. A new core fueled with fuel from the Materials Test 

Reactor in Idaho was installed. This increased the maximum rated power level to 1 MWt. The STIR 

operated from 1964 to 1972 when the fuel was removed and disposed of. The water from the reactor 

pool was drained in June 1973, and the facility was secured until September 1975 when D&D work 

began. D&D was completed in March 1976 and involved the removal of 1,500 ft3 of radioactive waste. 

After D&D, the facility was used for arc melting of depleted uranium. This work has been completed, 

and the arc-melting furnace has been removed. Additional D&D occurred and was complete in 1998. 

The above-grade portion of the facility was removed. The below-grade part of the building is again 

suitable for release for unrestricted use. 
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Incidents: There were no incidents of any consequence with the STIR. 

(7) SNAP 8 Development Reactor (S8DR), Building 4059. Building 4059 was built in 1962 to 1963 

for development testing of SNAP reactors. It had two reactor test cells in its basement. Testing of the 

S8DR, a second prototype SNAP 8 reactor, began in the north cell in June 1968 with the reactor 

operating under vacuum to simulate space flight conditions. A vacuum system and vacuum chamber 

were installed in a vault in the basement of Building 4059 for this test program. The S8DR operated 

from June 1968 to December 1969 at a power level between 600 kWthr and 1 MWthr. 

At the end of the test operations, the reactor core and control system were removed, sent to the Hot 

Lab for inspection, and then shipped off the site for disposal. At this time, sufficient D&D occurred to 

make a portion of the facility available for other use. The reactor cell was sealed, and the vacuum 

system prepared for storage. Further D&D of the facility (except for the reactor cell and vacuum 

system) occurred between June and September of 1978. 

The activated below-grade part of the facility was kept sealed and periodically inspected. An 

inspection in 1983 disclosed that groundwater was leaking into the reactor vault and becoming 

contaminated. Action was immediately taken to remove the contaminated water, process it, and 

dispose of it, and to begin a pumping program to ensure that radioactive water did not leak back out of 

the cell. The leak was found and sealed, and the situation was stabilized. However, another 

inspection in 1987 showed the potential for structural deterioration, so a D&D program was begun to 

remove the remaining radioactivity. 

D&D of the below-grade part of the facility has been underway since 1987. The work is being done in 

two phases. In Phase 1, completed in June of 1989, the vacuum system suction pipe and its sand 

shielding were removed. This required removal of 4,600 ft3 of radioactive waste. Phase 2 involves 

removing the vacuum chamber and the concrete test cell walls, which contain activation products. 

This work generated an additional 7,000 ft3 of radioactive waste containing about 58 Ci of 

radioactivity. Phase 2 was completed in 1992. At that time, the entire facility was released for 

unrestricted use. 

Incidents: Just as with the S8ER, cladding cracks due to fuel swelling and low cladding ductility 

occurred during the operation of the S8DR. As with the S8ER, there was no melting of the fuel or the 

cladding and all fission products were contained in the reactor system. 

2.2.1.2 Critical Test Facilities 

Several programs used critical test facilities (i.e., low-power reactors) in Area IV. Use of these lowpower reactors began in 1954 and continued until 1974. 

2.2.1.2.1 SNAP Development Test Facilities 

Test facilities in Area IV for the SNAP program included Buildings 4373, 4012, 4019, and 4024. 

(1) First SNAP Critical Facility, Building 4373. This was a critical test facility constructed in a building 

originally built to make high-energy rocket engine fuels. It was used for tests of five SNAP reactor 

critical assemblies (SCA-1, S2ERC, SCA-2, SCA¬3, and SCA-4C) between 1957 and 1963. It was 

later replaced by Building 4012, which was built specifically as a critical test facility. At the end of 

these tests, radiation surveys were performed and the facility was released for unrestricted use. The 

facility was resurveyed in 1987 and verified to be uncontaminated. 
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The D&D activities in Building 4373 were completed in 1995. Demolition of the building was 

completed in 2003. 

(2) Second SNAP Critical Facility, Building 4012. This facility was built to continue criticality testing of 

SNAP reactors. Three SNAP reactor critical assemblies (SCA-4A, SCA-4B, and SCA-5) were tested 

here for the AEC between 1961 and 1967, and additional criticality tests of space reactor 

configurations occurred for NASA through 1971. The critical assemblies and associated equipment 

were removed and disposed of, but some contamination remains in the test vault, which was used as 

a packaging area for a short time. From 1970 to 1972, Building 4012 housed a critical assembly for 

the Heavy Metal Reflected Fast Spectrum Reactor (HMRFSR). 

Initial demolition efforts in Building 4012 were completed in 1986 to accommodate construction of a 

non-nuclear building. Final D&D in the remaining portion of the building was performed in 1995. 

Demolition of the building was completed in 2003. 

(3) SNAP Flight System Critical Facility, Building 4019. This was built to test-qualify SNAP reactor 

power systems before delivery to the AEC for launch as space power systems. It was used for the 

criticality tests of the S10FS3 reactor before that was moved to SNAP Environmental Test Facility in 

Building 4024 for power tests. It was also used for testing of the SNAP 10A reactor and its backup 

launched in April 1965. Three reactors (FS-1, FS-4, and FS-5) were assembled and tested from 1964 

to 1965. This facility is not contaminated. 

The D&D activities for the SNAP Flight System Critical Facility were completed in 1965. Following 

additional decontamination in 1998, the building was released. The building remains standing and is 

inactive. 

(4) SNAP Transient Test Facility, Building 4024. Only operated in 1971, this was a criticality test 

facility set up in the same building as the SNAP Environmental Test Facility, where the S2DR and 

S10FS3 reactors were tested. It was used for low-power tests of the response of a SNAP reactor to 

rapid changes in control drum position. This was the SNAPTRAN test; the reactor criticality 

responses were studied at the SSFL, and then the reactor was moved to Idaho for power testing. 

After completion of SNAP operations the assemblies were removed from the building and sent off the 

site for disposal. D&D activities in Building 4024 were completed in 1978. At that time the nonvault 

portions of the building were declared suitable for release for unrestricted use. The test vaults remain 

restricted and have been in surveillance and maintenance mode since 1978. Additional D&D is 

scheduled to occur in 2005. 

2.2.1.2.2 Civilian Nuclear Power Test Facilities 

Critical test facilities supporting the development of civilian nuclear power included Buildings 4009 and 

4100.

(1) Organic Moderated Reactor (OMR) and Sodium Graphite Reactor (SGR), Building 4009. These 

two critical test facilities were operated in adjacent high-bays in Building 4009. During their operation, 

there were no incidents of contamination. When the programs ended, all associated equipment was 

removed. Later some additional test work occurred in a laboratory in this building that resulted in 

some radioactive contamination in the liquid waste holding tank system. It has been removed from 

SSFL. The east (SGR) high bay is now used for storage of Rockwell's in-service inspection 

equipment, which sometimes becomes slightly contaminated when used for inspecting reactors 

operating off the site. The west (OMR) high bay was used for tests of high energy rate forging 
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(HERF), which uses a variety of materials including depleted uranium. HERF can under certain 

circumstances increase materials strength. The developmental program conducted at SSFL yielded 

laboratory-sized samples to permit further study and understanding of the technique. There was 

about 800 lb of depleted uranium stored in Building 4009 as part of the HERF program. It has been 

removed. 

(2) Organic Moderated Reactor (OMR), Building 4009. This was a low-power critical experiment 

facility used for testing reactors moderated and cooled by organic liquids from 1958 to 1967. The 

critical assembly core used slightly enriched uranium fuel in a heterogeneous organic-moderated 

lattice. Various types and configurations of fuel elements and core geometries were tested. The 

OMR supported the development and construction of the Piqua Nuclear Power Facility. 

The D&D activities for the OMR were completed in 1967. Building 4009 is currently being used for 

non-nuclear R&D. 

(3) Sodium Graphite Reactor (SGR), Building 4009, Also a low-power critical experiment facility, the 

SGR was operated from 1958 to 1967 to determine the operating characteristics of reactors with 

cores cooled by sodium and moderated with graphite. The basic critical assembly was a cylindrical 

array of hexagonal graphite cylinders into which various amounts and configurations of fuel and 

sodium (in cans or simulated by aluminum) could be inserted. It supported the development and 

construction of the Hallam Nuclear Power Facility. 

The D&D activities for the SGR Critical Facility were completed in 1967. Building 4009 is currently 

being used for non-nuclear R&D. 

(4) Advanced Epithermal Thorium Reactor (AETR), Building 4100. The AETR was built to study and 

test reactor core configurations for thorium and uranium-fueled reactors. It supported the 

development of reactors for the Southwest Atomic Power Association. The reactor operated from 

1960 to 1974. 

The D&D activities for the AETR were completed after the program was terminated in 1974. Building 

4100 currently houses the radiation safety group’s counting and instrument calibration laboratory and 

a computer-aided tomography system. 

(5) Fast Critical Experiment Laboratory, Building 4100. This was a licensed facility built for the 

Southwest Atomic Power Association of private utility companies for epithermal and fast neutron 

criticality tests between 1961 and 1974. Twenty different reactor core configurations were studied. 

The early tests were of thorium- or uranium-fueled reactors that operated on neutrons of intermediate 

energies (epithermal flux spectra); later tests were of reactors with high-energy (fast) neutrons. It was 

decontaminated, decommissioned, and released for unrestricted use in 1980; the facility license was 

terminated October 1, 1980. It is now being used for office space and for storage and use of sealed 

radioactive sources for instrumentation calibration. The vault contains a computerized tomography 

device for nondestructive inspection of rocket engine components. 

2.2.1.3 Nuclear Support Operations 

Starting in 1956 several operations were conducted in Area IV to support nuclear programs. These 

included the manufacture, management, and disassembly of fuel for reactor operations as well as the 

operation of nuclear waste management facilities for offsite disposal. With the exception of the 

RMHF, Fuel Storage Facility, and the Radiation Instrument Calibration Laboratory, operations were 

terminated by 1988. Operations were terminated at the Fuel Storage Facility and Radiation 
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Instrument Calibration Laboratory in 1993 and 1996, respectively. Radiation instrument calibration is 

currently performed in Building 4100. The RMHF continues to operate in support of the DOE’s 

cleanup effort and will be terminated as the facility goes into closure. 

2.2.1.3.1 Reactor Fuel Manufacturing 

As part of the nuclear reactor development work performed for the government, three different reactor 

fuel manufacturing operations occurred at the SSFL in Buildings 4003, 4055, and 4064. The first 

operation was the assembly of fuel elements for the SRE, the second was a plutonium fuel 

manufacturing facility, and the third was a uranium carbide fuel pilot plant. There was also a Fuel 

Storage Facility, used to store the Special Nuclear Materials (enriched uranium and plutonium) used 

to make the fuels.

(1) Engineering Test Building (Building 4003). Building 4003 was built to support the SRE for 

assembly of SRE fuel elements and was used for many different types of developmental tests of 

reactor components. The assembly of SRE fuel elements involved loading of uranium and thorium 

metal slugs into metal tubes, filling the interstices with sodium metal, and sealing the tubes. Fuel 

elements for three cores were prepared, but only two were used. The third core was eventually 

shipped off the site. 

Research on reprocessing used reactor fuel occurred in the Hot Cave in Building 4003. D&D of this 

facility, including the Hot Cave, was completed in 1975. It required removal of 4,200 ft3 of waste. 

Some traces of radioactivity were later found in the drain line, which was removed. The facility has 

been released for unrestricted use. 

(2) Nuclear Materials Development Facility (NMDF), Building 4055. The NMDF was built specifically 

for development work involving plutonium fuel manufacturing and incorporated all of the safety 

systems and safeguards required for such work. It was completed in 1967 and operated with no 

unpermitted releases until 1979. Table 2-2 summarizes the NMDF’s operational history. 

Table 2-2. NMDF operational history. 

Operating 

period Operations

1967–1968 Development of analysis technologies for uranium-plutonium oxide fuels

4/68–6/69 Recycle of scrap uranium-plutonium fuel

7/68–6/70 Development of technologies to mix tungsten into uranium-plutonium carbide fuel

4/70–9/70 Preparation of samples for uranium-plutonium oxide irradiation studies

9/70–3/74 Idle

1974–1975 Bench scale tests, recovery of plutonium from simulated waste

1975–5/77 Mixed uranium-plutonium carbide fuel fabrication

5/77–11/78 Partial decontamination and cleanup

11/78–11/79 Fabrication of depleted uranium carbide fuel

11/79–10/82 Idle

10/82–10/86 D&D

7/87 Released for unrestricted use

D&D of Building 4055 is completed, and the building is released for unrestricted use. This required 

the removal of 692 ft3 of transuranic waste and 16,527 ft3 of other radioactive waste. The facility was 

removed from the Rockwell Special Nuclear Material License on October 7, 1987. 

(3) Uranium Carbide Fuel Manufacturing Pilot Plant, Building 4005. This was a small-scale 

production facility built to study the operations associated with manufacturing reactor fuel assemblies 
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from uranium carbide. In the pilot plant, uranium oxide was reacted with graphite to convert it to 

uranium carbide. The uranium carbide was cast into pellets, machined to the proper dimensions, and 

placed in cladding tubes to make fuel assemblies. The initial operations were with depleted uranium 

to check out the equipment, then enriched uranium was used to make fuel assemblies for a critical 

assembly to be built at another AEC facility. Operations were completed in about 9 months in 1967. 

Building 4005 was contaminated with enriched uranium. The building has been decontaminated 

except for some ventilation system ducts and filters, and some underground piping, which remain to 

be cleaned up. 

(4) Fuel Storage Facility, Building 4064. This was a vault built to provide secure storage for 

fissionable fuel material (enriched uranium and plutonium). The building was constructed above 

ground of concrete and concrete blocks to meet the AEC criteria for vaults for storage of fissionable 

materials. Closed containers of radioactive waste were stored outside on a concrete pad within the 

locked and fenced facility perimeter equipped with intrusion alarms. 

Some residual radioactive contamination was confirmed in the side yard outside the vault in a 1988 

radiation survey. Approximately 9 mCi of old mixed fission products was removed during cleanup of 

this yard. In removing this soil, approximately 9 mCi of natural radioactivity was also removed. D&D 

was completed in August 1989; 3,000 ft3 of contaminated material was removed. The exhaust system 

still contains some radioactive contamination, and there is some contaminated equipment inside the 

building. 

Following removal of all fissionable material in the mid-1980s, miscellaneous equipment and 

containers of radioactive waste (principally soil) were stored in the building. The building was emptied 

of all contents by 1993. D&D activities for Building 4064 were completed in 1997.

2.2.1.3.2 Disassembly and Examination of Reactors and Used Reactor Fuel Assemblies 

(1) Hot Lab, Building 4020. During reactor test operations, it was often necessary to examine reactor 

fuel assemblies and other test specimens to determine how they were performing. This involved 

handling and examining highly radioactive items, for which the Hot Lab operated in Building 4020 from 

1959 to 1990. The Hot Lab was a 16,000-ft2 facility with four large hot cells with remote manipulators 

and cranes, a mock-up area, an operating area, and decontamination areas. Construction was 

completed in 1959, and the facility was used until 1990. 

When a reactor operation was complete and the reactor was no longer needed, it was removed from 

its operating location, disassembled, the fuel removed, and the radioactive structure cut up into pieces 

small enough to be shipped for disposal. The disassembly, fuel removal, and size reduction 

operations usually involved working with highly radioactive materials, so many of these operations 

occurred in the Hot Lab. In addition, the Hot Lab was used for work on radioactive material generated 

outside the SSFL, which consisted in large part of used reactor fuel from other nuclear reactors. The 

fuel elements were shipped to the Hot Lab and disassembled or separated from their cladding 

material, and the separated materials were then shipped away. The Hot Lab was used to 

manufacture sealed sources (see Section 3.3.5), for leak checks on sources, and for cutting and 

machining operations involving 60Co.

The Hot Lab was used to examine fuel and/or components from the SRE, SER, S2DR, S8ER, S8DR, 

and S10FS3 reactors at the SSFL, the OMR and SGR criticality test facilities, and the Piqua, Ohio, 

reactor. It was also used to declad fuel from the SRE, EBR-I, EBR-II, Hallam, Fermi, and Southwest 

Experimental Fast Oxide Reactor reactors. 
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As a result of the work in the Hot Lab, the interior of the Hot Cells and the equipment they contain 

have been contaminated by small amounts of uranium, plutonium, thorium, and fission and activation 

products. Some exterior surfaces have become slightly contaminated as well. The extent of this 

contamination is approximately 2.2 Ci in the drain system, ventilation exhaust system, and inside the 

shielded cells plus traces of contamination on the building walls and surroundings. This radioactivity 

will be removed when the Hot Lab is decontaminated and decommissioned. During the period when 

the facility underwent D&D operations, the Hot Lab was being used for temporary storage of some 

radioactive materials. The license for this facility was changed in 1990 to limit operations to D&D 

work. D&D in Building 4020 were completed in 1999. 

Incidents: On May 19, 1971, a fire occurred in the process of disposal of about 100 gal of NaK (a 

sodium-potassium eutectic that is liquid at room temperature). The NaK contained about 100 Ci of 

mixed fission products. The fire was started upon loss of containment of the NaK when a hole was 

drilled in the tank fill line. Approximately 25 gal of NaK were released into the decontamination cell 

and burned. The normal facility high-volume ventilation system that draws all building air through 

high-efficiency particulate air (HEPA) filters confined essentially all combustion products to the Hot 

Lab. 

Airborne radioactivity and surface contamination monitored during and after the fire showed 

concentrations inside the building of between 2% and 20% of the occupational maximum permissible 

concentration (MPC). The average concentration of the release from the exhaust stack of the 

laboratory during the week of the fire was about 5% of the permitted concentration in an unrestricted 

area. No measurable external or internal exposures of radiation were received by personnel involved 

in the activities before or during the fire. 

2.2.1.3.3 Fabrication, Use, and Storage of Radioactive Sources 

Operations at SSFL required many instruments for detecting and measuring radioactivity, and these 

instruments must be calibrated periodically using known quantities and types of radioactivity called 

sources, which are sealed containers that contain small measured quantities of radioisotopes. 

Sources are also used for some forms of radiography, irradiation testing, and other applications. 

Sources were manufactured in the Hot Lab at SSFL and used in various facilities at SSFL and 

elsewhere. Approximately 140,000 Ci of radioactive material (primarily 147Pm) were fabricated into 

sources at the Hot Lab. They were stored in secured locations and used under carefully controlled 

conditions. There are currently less than 100 Ci in sources stored at SSFL. 

(1) Radiation Measurements Facility, Building 4029. This building housed storage and use of 

radioactive sources to calibrate radiation detection instruments for the SRE and other reactor tests. In 

March 1964 a radium source was dropped in a storage thimble. The plastic secondary encapsulation 

cracked and a small amount of radium contaminated the thimble. All of the sources were removed by 

April 1974, and the facility has since been used for temporary storage of nonradioactive materials. 

The contaminated thimble was removed and disposed of in October 1989. Radiation survey data 

shows that the facility now meets the requirements for release for unrestricted use. 

2.2.1.3.4 Preparation of Radioactive Material for Disposal 

The operation of nuclear reactors generates radioactive waste and other radioactive material that 

must be disposed of off the site. Other operations at the SSFL (fuel fabrication, reactor and fuel 

examination, etc.) also generated radioactive waste. Radioactive waste was prepared for disposal at 

the RMDF with support at the Interim Storage Facility (ISF) in Building 4654. 
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(1) Radioactive Materials Disposal Facility (RMDF). The RMDF was built in 1958 for fuel storage and 

processing solid and liquid waste for disposal in conjunction with the operation of the SRE. It has 

subsequently been used to support all of the SSFL nuclear operations. The facility consists of the 

following structures or areas: 

Building 4022 Radioactive material storage vault 

Building 4021 Decontamination and packaging facility 

Building 4075 Low Specific Activity waste storage 

Building 4621 Source storage 

Buildings 4034 & 4044 Offices 

Building 4665 Non-radioactive material storage 

Leach Field Sanitary sewer septic tank 

There was an incinerator and a flocculation tower at the facility, but they were removed. The 

incinerator was a test installation built to determine if some of the waste (paper, plastics, and fabrics) 

could be disposed of by burning. It was tested with nonradioactive waste and failed to function well, 

so it was dismantled. It was never tested with radioactive waste. The flocculation tower was built to 

pretreat radioactively contaminated water to make it easier to filter. It was made unnecessary by 

better filters and has since been removed. 

The RMDF is still in use, and parts of it are contaminated. The flocculation tower and the rest of the 

system used to treat radioactively contaminated water have been removed. The septic tank leach 

field was contaminated by a dilute solution of fission products (primarily cesium and strontium) in 1962 

by the inadvertent opening of a valve in a liquid waste system. The valve was removed, and the leach 

field has been cleaned up and released for unrestricted use. There was a small amount of radioactive 

contamination on the north slope of the hill below the facility that was cleaned up. Other buildings at 

the facility are still slightly contaminated. Because this facility is useful in supporting the cleanup of 

the other SSFL facilities, the facility itself will be cleaned up last. 

Incidents: Two noteworthy spills of dilute radioactive liquids occurred at the RMDF. The first was an 

accidental diversion of radioactive liquid into a sanitary system septic tank leach field. The valve that 

connected the radioactive system to the sanitary system was removed and the area was cleaned up 

and released for unrestricted use. The second incident was the loss of some liquid from the 

flocculation tower that overflowed and spilled down the north slope of the RMDF perimeter. As 

mentioned, the flocculation tower was removed and almost the entire spill was cleaned up. 

(2) Interim Storage Facility (ISF), Building 4654. The ISF was built in 1958 to store SRE fuel 

elements in 10 thimbles installed in holes drilled in bedrock. It was subsequently used for storage of 

fuel shipping casks for other reactors (OMRE and SNAP). It was taken out of service in 1964, the 

thimbles removed and the area decontaminated and released for unrestricted use. 

2.2.1.3.5 Research on Reprocessing Used Reactor Fuel 

(1) Hot Cave, Building 4003. The Hot Cave in the Engineering Test Building supported testing of 

nuclear fuel reprocessing. The used fuel assemblies from nuclear reactors contain unused fissionable 

material, fissionable transuranic products (mainly plutonium), and fission products. Rockwell 

developed a process to make a partial separation of used fuel, removing part of the fission products 

so that the material could be used again as reactor fuel. The experiments used up to kilogram 

quantities of unirradiated uranium and thorium, and up to 100-g quantities of highly irradiated 

materials. 
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2.2.1.3.6 Operation of Particle Accelerators 

(1) Particle Accelerator, Building 4030. There are other ways to generate artificial radioactivity 

besides nuclear fission. One way is to bombard a target material with atomic particles accelerated to 

high speeds by means of a particle accelerator. A common form of particle accelerator is a Van de 

Graaff generator, which uses a high-voltage electrostatic field to accelerate atomic particles to high 

speeds (high energy levels). Collisions of these particles with a target material (such as aluminum or 

tritium) can generate small amounts of radioactivity. Rockwell operated a Van de Graaff generator in 

Building 4030, bombarding tritium targets with deuterons to produce neutrons. 

A second Van de Graaff generator was operated for neutron activation analyses of materials. It was 

removed before the SRE facility was decontaminated and decommissioned. 

These accelerators were removed in 1962 and a radiation survey made of the facility showed it to be 

clean. A resurvey made in 1988 confirmed that there was no activation in the building. 

2.2.1.3.7 Research Using Radioisotopes 

Some of the research at the SSFL required the use of special radioisotopes. For these tests, small 

quantities of specially prepared radioisotopes were brought to the SSFL, used in laboratories under 

carefully controlled conditions, and then either shipped back out or stored safely when reuse was 

required. 

The Transuranic Management by Propartitioning-Separation (TRUMP-S) program used research 

amounts of radioisotopes to develop fundamental thermodynamic and electrochemical data on 

various transuranic materials so that processes could be developed to separate long-lived radioactive 

isotopes from spent nuclear fuel. These long-lived radioactive isotopes could then be destroyed by 

fissioning them in a nuclear reactor or accelerator, thereby eliminating the long-term hazard 

associated with the disposal of spent nuclear fuel. The program used small quantities of transuranic 

materials (plutonium, neptunium, and americium). 

(1) Fuel Storage Facility, Building 4064. The Fuel Storage Facility contains the materials for the 

TRUMP-S tests, which were planned to be in the Hot Lab but were transferred to the University of 

Missouri. The material included 75 g of depleted uranium, 5 g of plutonium, 4 g of neptunium, and 4 g 

of americium, which was shipped to Missouri. Building 4064 no longer stores any Special Nuclear 

Material and is scheduled for D&D. 

(2) Corrosion Testing Laboratory, Building 4023. Another radioisotope research program was a 

corrosion test in the Corrosion Testing Laboratory. A pumped sodium corrosion test loop was built for 

study of the deposition behavior of activation products (54Mn and 60Co) in flowing sodium to develop 

more effective traps for these isotopes. An activated piece of fuel cladding containing these isotopes 

was used in these tests. The test specimens and the test loop were removed from the building. 

Some slight contamination of the ventilation exhaust system and drains remains. 

2.2.1.3.8 Miscellaneous Operations 

Neither the Conservation Yard nor the Sodium Disposal Facility was intended for use with radioactive 

materials, but both were inadvertently contaminated. 

(1) Conservation Yard. This outdoor area was used for storage and salvage of used equipment. A 

20-by-20-ft area of the surface of the Conservation Yard was found to be slightly contaminated (total 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 27 of 47

activity on the order of 0.001 Ci) by radioactivity in 1988. A total of 132 ft3 of contaminated soil and 

asphalt was removed and shipped off the site for disposal. The site was released for unrestricted use 

in 1995. 

(2) Sodium Disposal Facility. Also called the sodium burn pit, this facility was built to clean 

nonradioactive metallic sodium and NaK from various scrap test components (pumps, valves, etc.) 

before they were disposed of. In addition, it was used to treat nonradioactive waste sodium and NaK, 

and to burn nonradioactive combustible liquid waste (oils, etc.). The facility consisted of a large, 

rectangular, concrete-lined pit filled with water, surrounded by a concrete slab with two water-filled 

basins, a small building (Building 4886), and steam lance cleaning equipment. 

Components were placed on the slab, opened to expose the sodium or NaK, and washed with water. 

The water reacted with the sodium to generate hydrogen, which often burned in the air. Sometimes 

the sodium and NaK also burned. The washed items were then often placed into the pit where the 

reaction with water continued, then placed into one of the basins where they were allowed to remain 

until any residual sodium or NaK was reacted. They were then retrieved and disposed of off site as 

solid waste. 

One hazardous feature of sodium and NaK disposal was when an imperfectly sealed container (left 

slightly open to the atmosphere) was handled. A chemically unstable layer of sodium hydroxide and 

water and/or potassium superoxide could form on the surface of the sodium or NaK. If this layer was 

disrupted, a violent reaction could occur. Therefore, containers suspected of having this unstable 

characteristic were very carefully taken to the disposal field where they would be opened to the 

atmosphere from a safe distance by Security personnel using a high-powered rifle. After this 

procedure was completed and the violent reactions were allowed to occur, the material would be 

allowed to react with the atmosphere for a while. 

The sodium-water and NaK-water reactions generated sodium hydroxide and potassium hydroxide, 

which subsequently reacted with carbon dioxide in the air to form sodium carbonate and potassium 

carbonate, both nonhazardous materials. Combustible nonradioactive liquids such as oils or 

biphenyls (an organic material used as a heat transfer fluid) were burned near the concrete-lined pit. 

The concrete-lined pit was cleaned out and resurfaced, and the basins are now dry. Several areas of 

the contaminated basin were dug out, and several small parts of scrap test components containing 

radioactivity were found and removed. Most of the buried nonradioactive waste has been excavated 

and removed. The site was remediated, revegetated, and released for unrestricted use in 1998. 

In the 1960s tests were conducted at Area IV to determine how deeply a falling radioisotope heat 

source would penetrate the soil. During one of these tests a 1-kg slug of depleted uranium was lost 

after being dropped from a helicopter. No documentation was found to suggest the slug was ever 

recovered. The area where the slug was dropped has been surveyed several times and 

contamination has not been detected. Further reconnaissance is planned to recover the missing slug. 

2.2.2 Other Relevant Facilities

2.2.2.1 Downey 

The Downey facility is on Lakewood Boulevard in Downey, California. AEC-funded activities were 

performed by Rockwell’s Atomics International Division in a small portion of this large building 

between 1948 and 1955. AEC activities included mainly paper studies, research and development, 

and engineering studies. However, these activities also involved the use of a 2-MeV Van de Graaff 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 28 of 47

generator, a small-scale radiochemical laboratory, a neutron counting room, and a construction area 

with a small 0.5-W teaching reactor. In addition, the AEC funded a 4-W WBNS at the Downey facility. 

Startup for the reactor was in April of 1952. The reactor fuel was uranyl sulfate with a sealed 

polonium and beryllium neutron source; only very small quantities of radioactive material were ever 

present at the facility. There were 3 Ci of radioactive material present when the reactor was at full 

power. The WBNS operated at Downey until December 1955. In 1956 it was dismantled and moved 

to Area IV. Personnel and operations from Downey moved to the Canoga Avenue facility in late 1955. 

The major quantity of radioactive material at Downey was canned normal and depleted uranium metal 

used in the exponential pile. The exponential pile was a system designed to model different 

fuel/moderator lattice configurations. The behavior of neutron flux in these lattices was measured. 

The 4-W WBNS was used as a neutron source for the exponential pile. The radioactive material was 

obtained from a variety of AEC and government contractors. After use it was returned to the source 

or transferred to the SSFL. The loading dock was the only place where the fuel was stored. All 

isotopes used at Downey by Rockwell were used for industrial radiography at Building 004, on Clark 

Avenue. All isotopes were disposed of in the early 1990s. 

Effective remediation of the Downey facility was accomplished in 1956. In 2000, Boeing performed a 

survey verifying that the previous remediation met current NRC and California requirements. 

Ownership of the Downey facility was then transferred to the City of Downey. 

2.2.2.2 Canoga Park 

AEC-funded activities at Rockwell’s Canoga Park, California, occurred in the Vanowen Building from 

approximately 1954 to 1960. This work had been performed at North American Aviation’s Downey 

Facility, but was moved to Canoga Avenue at the end of 1955. Principal work in the Vanowen 

Building included design, development, and operation of small aqueous fuel reactors, fuel 

development, and radiochemistry, and beryllium machining is believed to have occurred. The 

reactors activities involved the construction of small 10-W aqueous uranyl sulfate homogeneous 

reactors named L-47 and L-77 for use in training institutions. Reactor fueling occurred only after the 

reactors were installed at the training institutions. A few fuel elements for the organic moderated 

reactor were fabricated at this facility. 

Facilities where AEC-funded work took place within the Vanowen Building included the machine shop 

(where some beryllium machining took place), a radiochemical laboratory, and office space. The 

wastewater from all facilities except the laboratory discharged into a common treatment plant. The 

wastewater from the radiochemical laboratory went to a clarifier, where it was tested for radioactivity 

before being released to the sanitary sewer if it was below established standards. The sludge from 

the clarifier was disposed of in a government repository or an AEC site for low-level waste. 

Once the AEC work was completed, the clarifier was surveyed for radioactivity, determined to be 

within acceptable standards, and backfilled. The transfer lines from the clarifier to the sewer main 

could still be present, but they are not in use. 

2.2.2.3 DeSoto 

Radiological operations occurred at the DeSoto Facility from 1959 to the mid-1990s. AI used nuclear 

fuel material and other radioactive materials in Buildings 101 and 104 from 1959 to 1983. A muchreduced level of work was continued by Rocketdyne in Building 104 into the mid-1990s. Before 1984, 

Buildings 101 and 104 were designated as 001 and 004. Much of the historical documentation refers 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 29 of 47

to these building numbers. The following paragraphs briefly summarize the nuclear operations in 

these buildings. 

L-77 Reactor (NRC Licensed). The L-77 small research reactor operated in Room 416-61 of Building 

104 from 1960 to 1976. The L-77 was a low-power (10 W) reactor using enriched uranyl sulfate 

solution. The L-77 was a prototype teaching reactor sold to many universities and around the world. 

The laboratory housing L-77 was decommissioned and decontaminated in the late 1970s. The NRC 

released the facility for unrestricted use and terminated the reactor’s license in February 1982. 

Advanced Test Reactor (ATR) Fuel Fabrication and Supporting Activities. NRC-licensed fuel 

fabrication operations were conducted in the northern section of the first floor of Building 101, with 

radiochemistry support operations conducted on the first and second floors of Building 104. These 

support activities included hot chemistry laboratories (east section of second floor), an emission 

spectroscopy laboratory (Room 411-72, first floor), and an X-ray diffraction laboratory (Room 411-58, 

first floor). The fuel fabrication facility produced a variety of different fuel elements for test reactors. 

Many fuel manufacturing programs began in 1959 using 2% to 93% enriched uranium metal and 

composites. Some of the work involved developing uranium-aluminum alloys and, because of the 

uranium, occurred in sealed gloveboxes. One of the larger programs was fuel manufacture for the 

ATR using uranium-aluminum (UAlX) powder with an enrichment of 93%. Fuel manufacturing ended 

in 1983. In addition, AEC-sponsored work involving the manufacture of beryllium-containing parts 

took place at this site. 

D&D of Buildings 101 and 104 included removal of all fuel and radioactive materials and waste; 

removal of contaminated equipment, drain lines, tanks, and ventilation ducts; and cleaning of all 

surfaces including floors, walls, and ceilings. 

Gamma Irradiation Facility (GIF). This state-licensed aboveground vault in Building 104 used sealed 

137Cs and 60Co sources for radiation hardening tests of electronic components and for food irradiation 

research. The Gamma Irradiation Facility consisted of Rooms 41M-11 and 41M-11A on the northeast 

corner of Building 104. Activity ceased in the late 1980s, and the sources were shipped off the site for 

recycling in the early 1990s. Bi-annual leak checks of these sources detected no leaks. In 1995, a 

Rocketdyne survey of the GIF verified that it was not contaminated. 

Mass Spectroscopy Laboratory (Helium Laboratory). Up until 1995, Rocketdyne used the statelicensed Mass Spectroscopy Laboratory to analyze miniature radioactive specimens of neutronirradiated nonfissile metals from DOE and international reactors for helium content. The Mass 

Spectroscopy Laboratory consisted of Rooms 414-69, 416-72, 414-75, 416-76, 416-76A, 414-77, 

416-80, 416-80A, and 414-81 in the northeast section of the 1st floor of Building 104. Operations of 

the DeSoto Mass Spectrometer Laboratory generated very small quantities of radioactive, hazardous, 

and mixed waste, including radioactive solvents, solvent wipes, and acids shipped from other U.S. 

and international research organizations. In 1995, the equipment was shipped to Pacific Northwest 

National Laboratory in Richland, Washington, where it continues to be used. 

Fuel fabrication was terminated in 1984, but small-scale laboratory research work on gamma 

irradiation and analysis of radioactive samples continued until 1995. Remedial activities occurred at 

various times in the 1980s followed by NRC license termination. In mid-1998, all remaining 

equipment, interior walls, and drain lines were removed, and the facility was decontaminated. 

Residual contamination was low level and confined to the laboratory. No elevated radiation levels or 

contamination outside the laboratory were detected before or during D&D. 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 30 of 47

Former sewage lines connecting sinks and showers at Building 101 were plumbed into a network that 

discharged into a pair of 1,500-gal steel holding tanks. The tanks allowed sufficient time for sampling 

and analysis of the sanitary water before discharge to the main municipal sewer line. If the 

concentration of radionuclides was below the MPC, the water was released to the municipal sewer. 

Overly contaminated water would have been transported to the RMDF for evaporation, but no water in 

the holding tanks was ever above the MPC. During decommissioning of the facility in the 1980s, 

radioactive contamination of the small areas of soils adjacent to some of the drain lines was slightly 

above acceptable limits. Approximately 10 of 140 soil samples had activities in the range of 50 to 80 

pCi/g in comparison to the NRC limit of 48 pCi/g. D&D included the removal of the holding tanks and 

excavation of contaminated soil. The outflow lines from the holding tanks to the main sewer between 

Buildings 101 and 104 remain in place. 

2.3 ISOTOPES OF CONCERN 

Table 2-3 identifies the potential radiological contaminants associated with the specific nuclear 

operations at SSFL in terms of isotopes of concern. The guidance for the preparation of Site Profiles 

(ORAU 2005) requires for this table to include dose reconstruction parameters such as the solubility 

type and assumed particle size of the contaminants, although the same information is also required in 

Section 5, Internal Dosimetry. Since this Site Description section, Section 2, is for informational use 

only, the data given in Section 5 should be used for dose reconstruction, regardless. 

In the absence of any measurements or studies, NIOSH guidance requires the use of default solubility 

classes and particle size values from the International Commission on Radiological Protection 

(NIOSH 2002, pp. 15, 16). With one exception, facility-specific solubility and particle size data for 

ETEC has not been found. 

2.4 MAGNITUDE OF SITE ACTIVITY 

Table 2-4 intends to provide a perspective of the magnitude of the nuclear operations at SSFL. The 

Site Profile preparation guide (ORAU 2005) requires the magnitude of the operations be expressed in 

radioactivity (Ci) of the isotope of concerns. Again, the same information is also required in Section 5, 

Internal Dosimetry. Hence, radioactivity values in Section 5 should be used for dose reconstruction. 

In cases where available information allows the estimation of the radioactivity at the time of the 

operations, the number of curies of each isotope is listed. In cases where numeric data is not 

available, the table locates the descriptive text that gives the magnitude of the nuclear operations. 

Activity fractions were not available with the exception of those for limited fuel fabrication operations. 

For highly enriched research reactors, values from Shleien, Slayback, and Birky (1998) have been 

listed as an approximation. For other areas, default assumptions from Barnes (1999, Table D-3) have 

been used. By coupling the activity fractions with the data in Table 2-5, the radioactivity for each of 

the isotope of concern can be derived. 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 31 of 47

Table 2-3. Area information and parameters of nuclear operations. 

Section Name

Period of

operationsaFacility

Radioactivity

RadioisotopesSolubility 

type

Part’le size

(μm

AMAD)

Reactor operations

2.2.2.1 WBNS Reactor/

0.5 Wthr

1952-1955 Downey Plant Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241 

Am-241

F

F

M

M

M

S

S

S

S

M

5

5

5

5

5

5

5

5

5

5

2.2.2.2 L-47, L-77

10 Wthr

1954-1960 Vanowen facility

2.2.2.3 L-77

10 Wthr

1960-1976 DeSoto Facility

Bldg. 104

2.2.1.1.1 (1) KEWB Reactor

1 kWthr

1956-1966 Building 4073

(2) L-85 Reactor

3 kWthr

1956-1980 Building 4093

2.2.1.1.2

(1)

SRE Reactor

20 MWthr

1957-1964 Building 4143 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

Th-232

H-3

F

F

M

M

M

S

S

S

S

M

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

5

5

2.2.1.1.3

(1)

SER

50 kWthr

1959-1960 Building 4010 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

H-3

F

F

M

M

M

S

S

S

S

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

5

(2) S8ER

600 kWthr

1963-1965

(3) S2DR

50 kWthr

1961-1962 Building 4024

(4) S10FS

7 kWthr

1965-1966

2.2.1.2.1

(4)

SNAP Transient Test 

Facility 

1971

(5) STR

50 kWthr

1961-1964 Building 4028

(6) STIR

1 MWthr

1964-1972

(7) S8DR

600 kWthr - 1 MWthr

1968-1969 Building 4059

2.2.1.2.1

(2)

SNAP Critical Test Facility 1962-1968 Building 4012 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

F

F

M

M

M

S

S

S

S

M

5

5

5

5

5

5

5

5

5

5

HMRFSR 1970-1972

2.2.1.2.1

(1)

SNAP Critical Test Facility 1957-1963 Building 4373

(3) SNAP Flight System Critical

Facility 

1964-1965 Building 4019
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 32 of 47

Table 2-3 (Continued). Area information and parameters of nuclear operations. 

Section Name

Period of 

operationsaFacility

Radioactivity

RadioisotopesSolubility 

type

Part’le size

(μm

AMAD)

Reactor operations (continued)

2.2.1.2.2

(2)

OMR Critical Facility 1958-1967 Building 4009 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

F

F

M

M

M

S

S

S

S

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

5

(3) SGR Critical Facility 1958-1967

(4) AETR Test Facility 1960-1974 Building 4100 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Th-232

F

F

M

M

M

S

S

S

S

M

M

5

5

5

5

5

5

5

5

5

5

5

Nuclear Support Operations

DeSoto Facility 1966-1968 Building 101

(powder room)

U-234

U-235

U-236

U-238

S

S

S

S

1

1

1

1

2.2.1.3.1

(1)

2.2.1.3.5

(1)

SRE Support Complex 1954-1964 Buildings 4003, 4163, 

4041, 4654, 4689, 

4653, 4606,4773

Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

Th-232

F

F

M

M

M

S

S

S

S

M

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

5

5

2.2.1.3.1

(3)

Uranium Carbide Fuel Pilot 

Plant

1964-1967 Building 4005 U-234

U-235

U-238

M

M

M

5

5

5

Radiation Instrument

Calibration Laboratory

1984-1996 Building 4011 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

Th-232

F

F

M

M

M

S

S

S

S

M

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

5

5
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 33 of 47

Table 2-3 (Continued). Area information and parameters of nuclear operations. 

Section Name

Period of 

operationsaFacility

Radioactivity

RadioisotopesSolubility 

type

Part’le size

(μm

AMAD)

Nuclear Support Operations (continued)

2.2.1.3.6

(1)

Van de Graaff Accelerator 1960-1964 Building 4030 H-3

2.2.1.3.2

(1)

Hot Laboratory 1957-1988 Building 4020 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

Pm-147

F

F

M

M

M

S

S

S

S

M

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

5

5

2.2.1.3.7

(2)

Liquid Metals Component

Test Building 

1962-1986 Building 4023 Sr-90

Cs-137

Co-60

Eu-152

Eu-154

F

F

M

M

M

5

5

5

5

5

2.2.1.3.3

(1)

Radioactive Measurement

Facility 

1959-1974 Building 4029 Ra-226 M 5

2.2.1.3.1

(2)

NMDF 1967-1979 Building 4055 U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

M

M

M

S

S

S

S

5

5

5

5

5

5

5

2.2.1.3.1

(4)

2.2.1.3.7

(1)

Fuel Storage Facility 1958-1993 Building 4064 Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

F

M

M

M

S

S

S

S

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

2.2.1.3.4

(1)

RMDF 1959-present Buildings 4021/4022 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

H-3

F

F

M

M

M

S

S

S

S

M

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

5

5

Mechanical Component

Development and Counting

Building

1956-1963 Building 4363 Sr-90

Cs-137

F

F

5

5
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 34 of 47

Table 2-3 (Continued). Area information and parameters of nuclear operations. 

Section Name

Period of 

operationsaFacility

Radioactivitiy

RadioisotopesSolubility 

type

Part’le size

(μm

AMAD)

Nuclear Support Operations (continued)

2.2.1.2.2

(4)

(5)

Radiation Instrument

Calibration and

Radiological Sample

Counting Laboratory

1985-present Building 4100 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

H-3

F

F

M

M

M

S

S

S

S

M

M

M

M

M

5

5

5

5

5

5

5

5

5

5

5

5

5

5

a. For reactors, refers to operation of the reactor rather than program duration dates provided in Figure 2-2. 

Table 2-4. Magnitude of nuclear operations. 

Section Name, Rating, PeriodaFacility

Radioisotopes

Magnitude

Ci

Text

description

Reactor operations

2.2.2.1 WBNS Reactor/

0.5 Wthr

1952-1955

Downey Plant Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241 

Am-241

1.47E+00

1.53E+00

1.61E-07

3.72E-06

5.79E-08

1.99E-03

3.66E-05

1.72E-05

9.99E-04

3.48E-06

2.2.2.1

2.2.2.2 L-47, L-77/

10 Wthr

1954-1960

Vanowen 

facility

-- -- 2.2.2.2

2.2.2.3 L-77/

10 Wthr

1960-1976

DeSoto Facility

Bldg. 104

-- -- 2.2.2.3

2.2.1.1.1 (1) KEWB Reactor

1 kWthr

1956-1966

Building 4073 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241 

Am-241

2.93E+03

3.06E+03

3.22E-04

7.44E-03

1.16E-04

3.97E+00

7.32E-02

3.44E-02

2.00E+00

6.96E-03

2.4.1

(2) L-85 Reactor

3 kWthr

1956-1980

Building 4093 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241 

Am-241

8.80E+03

9.18E+03

9.65E-04

2.23E-02

3.47E-04

1.19E+01

2.20E-01

1.03E-01

5.99E+00

2.09E-02

2.4.1
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 35 of 47

Table 2-4 (Continued). Magnitude of nuclear operations. 

Section Name, Rating, PeriodaFacility

Radioisotopes

Magnitude

Ci

Text

description

Reactor operations (continued)

2.2.1.1.2

(1)

SRE Reactor

20 MWthr

1957-1964

Building 4143 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

Th-232

H-3

--

--

--

--

Total 

activity

1.20E+08

--

--

--

--

2.4.1

2.2.1.1.3

(1)

SER

50 kWthr

1959-1960

Building 4010

Sr-90

Cs-137

U-234

U-235

U-238 

Pu-238

Pu-239

Pu-240

Pu-241

Am-241 

Co-60

Eu-152

Eu-154

H-3

1.47E+05

1.53E+05

1.61E-02

3.72E-01

5.79E-03

1.99E+02

3.66E+00

1.72E+00

9.99E+01

3.48E-01

--

--

1.94E+03

6.18E+02

2.4.1

(2) S8ER

600 kWthr

1963-1965

Building 4010 Sr-90

Cs-137

U-234

U-235

U-238 

Pu-238

Pu-239

Pu-240

Pu-241

Am-241 

Co-60

Eu-152

Eu-154

H-3

1.76E+06

1.84E+06

1.93E-01

4.46E+00

6.95E-02

2.38E+03

4.39E+01

2.06E+01

1.20E+03

4.18E+00

--

--

2.32E+04

7.42E+03

2.4.1

(3) S2DR

50 kWthr

1961-1962 

Building 4024 Sr-90

Cs-137

U-234

U-235

U-238 

Pu-238

Pu-239

Pu-240

Pu-241

Am-241 

Co-60

Eu-152

Eu-154

H-3

1.91E+05

1.99E+05

2.09E-02

4.84E-01

7.53E-03

2.58E+02

4.76E+00

2.23E+00

1.30E+02

4.52E-01

--

--

2.52E+03

8.03E+02

2.4.1
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 36 of 47

Table 2-4 (Continued). Magnitude of nuclear operations. 

Section Name, Rating, PeriodaFacility

Radioisotopes

Magnitude

Ci

Text

description

Reactor operations (continued)

(4) S10FS

37 kWthr

1965-1966

Building 4024 Sr-90

Cs-137

U-234

U-235

U-238 

Pu-238

Pu-239

Pu-240

Pu-241

Am-241 

Co-60

Eu-152

Eu-154

H-3

2.93E+06

3.06E+06

3.22E-01

7.44E+00

1.16E-01

3.97E+03

7.32E+01

3.44E+01

2.00E+03

6.96E+00

--

--

3.87E+04

1.24E+04

2.4.1

2.2.1.2.1

(4)

SNAP Transient Test 

Facility

1971

Building 4024 Sr-90

Cs-137

U-234

U-235

U-238 

Pu-238

Pu-239

Pu-240

Pu-241

Am-241 

Co-60

Eu-152

Eu-154

H-3

--

--

--

--

--

--

--

--

--

--

--

--

--

--

2.4.1

(5) STR

50 kWthr

1961-1964

Building 4028 Sr-90

Cs-137

U-234

U-235

U-238 

Pu-238

Pu-239

Pu-240

Pu-241

Am-241 

Co-60

Eu-152

Eu-154

H-3

1.47E+05

1.53E+05

1.61E-02

3.72E-01

5.79E-03

1.99E+02

3.66E+00

1.72E+00

9.99E+01

3.48E-01

--

--

1.94E+03

6.18E+02

2.4.1

(6) STIR

1 MWthr

1964-1972

Building 4028 Sr-90

Cs-137

U-234

U-235

U-238 

Pu-238

Pu-239

Pu-240

Pu-241

Am-241 

Co-60

Eu-152

Eu-154

H-3

1.82E+06

1.89E+06

1.99E-01

4.61E+00

7.17E-02

2.46E+03

4.53E+01

2.13E+01

1.24E+03

4.31E+00

--

--

2.40E+04

7.65E+03

2.4.1
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 37 of 47

Table 2-4 (Continued). Magnitude of nuclear operations. 

Section Name, Rating, PeriodaFacility

Radioisotopes

Magnitude

Ci

Text

description

Reactor operations (continued)

(7) S8DR

600 kWthr - 1 MWthr

1968-1969

Building 4059 Sr-90

Cs-137

U-234

U-235

U-238 

Pu-238

Pu-239

Pu-240

Pu-241

Am-241 

Co-60

Eu-152

Eu-154

H-3

1.08E+05

1.12E+05

1.18E-02

2.73E-01

4.25E-03

1.46E+02

2.68E+00

1.26E+00

7.33E+01

2.55E-01

--

--

1.42E+03

4.53E+02

2.4.1

2.2.1.2.1

(2)

SNAP Critical Test Facility 

1962-1968

Building 4012 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

--

--

--

--

--

--

--

--

--

--

2.4.2

HMRFSR

1970-1972

2.2.1.2.1

(1)

SNAP Critical Test Facility 

1957-1963

Building 4373

(3) SNAP Flight System Critical

Facility

1964-1965

Building 4019

2.2.1.2.2

(2)

OMR Critical Facility.

1958-1967

Building 4009 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

--

--

--

--

--

--

--

--

--

--

--

--

--

--

2.4.2

(3) SGR Critical Facility.

1958-1967

(4) AETR Test Facility.

1960-1974

Building 4100 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Th-232

--

--

--

--

--

--

--

--

--

--

--

2.4.2

Nuclear Support Operations

2.2.2.3 DeSoto Facility

1966-1968

Building 101

(powder room)

U-234

U-235

U-236

U-238

--

--

--

--

2.2.2.3
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 38 of 47

Table 2-4 (Continued). Magnitude of nuclear operations. 

Section Name, Rating, PeriodaFacility

Radioisotopes

Magnitude

Ci

Text

description

Nuclear Support Operations (continued)

2.2.1.3.1

(1)

2.2.1.3.5

(1)

SRE Support Complex 

1954-1964

Buildings 4003,

4163, 4041, 

4654,

4689, 4653, 

4606,4773

Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

Th-232

--

--

--

--

Total 

Activity

1.20E+08

--

--

--

--

--

--

2.4.3

2.4.7

2.2.1.3.1

(3)

Uranium Carbide Fuel Pilot 

Plant

1964-1967

Building 4005 U-234

U-235

U-238

--

--

--

--

2.2.1.3.1

(3)

Radiation Instrument

Calibration Laboratory

1984-1996

Building 4011 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

Th-232

--

--

--

--

--

--

--

--

--

--

--

--

--

--

2.2.1.3.6

(1)

Van de Graaff Accelerator 

1960-1964

Building 4030 H-3 -- 2.2.1.3.6

(1)

2.4.8

2.2.1.3.2

(1)

Hot Laboratory

1957-1988

Building 4020

Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154 

Pm-147

2.93E+06a

3.06E+06

3.22E-01

7.44E+00

1.16E-01

3.97E+03

7.32E+01

3.44E+01

2.00E+03

6.96E+00

--

--

3.87E+04

1.40E+05

2.4.4

2.4.5

2.2.1.3.7

(2)

Liquid Metals Component

Test Building 1962-1986

Building 4023 Sr-90

Cs-137

Co-60

Eu-152

Eu-154

--

--

--

--

--

2.2.1.3.7

(2)

2.4.9

2.2.1.3.3

(1)

Radioactive Measurement

Facility 

1959-1974

Building 4029 Ra-226 -- 2.2.1.3.3

(1)
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 39 of 47

Table 2-4 (Continued). Magnitude of nuclear operations. 

Section Name, Rating, PeriodaFacility

Radioisotopes

Magnitude

Ci

Text

description

Nuclear Support Operations (continued)

2.2.1.3.1

(2)

NMDF

1967-1979

Building 4055 U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

--

--

--

--

--

--

--

--

2.4.6

2.2.1.3.1

(4)

2.2.1.3.7

(1)

Fuel Storage Facility 

1958-1993

Building 4064 Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

--

--

--

--

--

--

--

--

--

--

--

--

2.2.1.3.7

(1)

2.4.3

2.4.9

2.2.1.3.4

(1)

RMDF 

1959-present

Buildings 4021/ 

4022

Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

H-3

--

--

--

--

--

--

--

--

--

--

--

--

--

2.4.6

Mechanical Component

Development and Counting

Building

1956-1963

Building 4363 Sr-90

Cs-137

--

--

2.2.1.2.2

(4)

(5)

Radiation Instrument

Calibration and

Radiological Sample

Counting Laboratory

1985-present

Building 4100 Sr-90

Cs-137

U-234

U-235

U-238

Pu-238

Pu-239

Pu-240

Pu-241

Am-241

Co-60

Eu-152

Eu-154

H-3

--

--

--

--

--

--

--

--

--

--

--

--

--

--

2.2.1.2.2

(4)

(5)

a. The radioactivity of S10FS3 is listed. It represents the highest radioactivity in low-power reactors at 

the site. 

2.4.1 Operation of Nuclear Reactors

Operation of a nuclear reactor creates three sources of radioactivity: Fission, transuranic, and 

activation products. When part of the fissionable material in the fuel element is used up, or when a 

reactor is decommissioned, the fuel elements are removed. These spent fuel elements contain the 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 40 of 47

fission products and transuranic materials generated by operation of the reactor, and the activation 

products in the cladding. The amount of radioactivity generated by a nuclear reactor depends in part 

on the amount of heat it generates. The heat generated is measured in thermal watts. The reactors 

at SSFL all operated at low power levels. Six had power levels of less than 100 kWt, three had power 

levels of 600 to 1,000 kWt, and one was a 20-MWt test reactor. 

The amount of radioactivity generated by a nuclear reactor is not measured while the reactor is 

operating, but it can be calculated from the power level and other parameters of the reactor. The 

radioactivity generated per watt of power is a function of operating time. However, an equilibrium is 

reached after about 1 year of operation, wherein the amount of new radioactivity being generated is 

balanced by the decay of short-lived fission products. This equilibrium radioactivity is approximately 

6 Ci/Wt for a reactor that has operated between 1 and 10 years. This value agrees with the results of 

a nuclear reactor design computer code (RSIC 1987) and with measured data (5.6 Ci/W from 

Glasstone and Sesonske 1981). Therefore, the curies of radioactivity in a reactor can be estimated 

(conservatively) by multiplying its thermal power level in watts by 6. 

Small amounts of tritium can be formed when neutrons from reactors are absorbed by the lithium 

naturally present in minute quantities in the granite aggregate used in the concrete shielding. When a 

6

Li atom absorbs a neutron, it transmutes into an alpha particle (helium nucleus) and tritium. 

There have been 10 different nuclear reactors at the SSFL in seven different facilities over the last 

30 years. Table 2-5 lists the reactor name, building number, facility name, nominal power level, 

operating period, total power generated, and calculated level of radioactivity for each reactor. 

A total of 135 million Ci of radioactivity was generated in the fuel from about 7,200 MWd of total 

reactor operation; a much smaller amount (perhaps several thousand curies) was generated as 

activation products in the reactor vessels, shields, and facilities. Figure 2-6 is a graph of the amount 

of radioactivity at Area IV as a function of time. As the graph shows, the vast majority of the 

radioactivity has been removed, but about 60 Ci remains among a few reactor sites and other 

facilities. Almost 90% of the total SSFL radioactivity was generated by the 20-MWt SRE. 

The total amount of artificial radioactivity in the form of activation products and contamination still 

present at SSFL is about 60 Ci; over 99% of this is contained in a controlled manner in activated or 

contaminated structures that are locked, fenced, and within a guarded perimeter. There is calculated 

to be less than 0.1 Ci that is unconfined. The unconfined radioactivity is present in very low 

concentration levels in three areas. Access to these areas is controlled and restricted in accordance 

with applicable regulations. Routine surveys show that this radioactivity is not mobile. 

The distinct steps in Figure 2-6 represent the discontinuation of SRE operations in 1964, the SNAP 

reactors in 1972, and the L-85 experimental reactor in 1980. The current residual contamination and 

activation level of 60 Ci is predominantly (58 Ci) attributed to the SNAP Ground Prototype Test Facility 

(Building 4059) where final decontamination was completed in 1992. 

2.4.2 Operation of Criticality Test Facilities

A controlled nuclear chain reaction can only be sustained when the neutrons generated by fission of 

the reactor fuel balance the neutrons used up and lost. When the reactor is adjusted so that this 

balance is achieved, it is said to be critical. Criticality can be achieved in several ways such as by 

bringing parts of a core of fissionable material together (to reduce the number of neutrons that 

escape) or by removing control rods (to reduce the number of neutrons captured in the control rods). 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 41 of 47

Table 2-5. Reactor operations (Oldenkamp and Mills 1991). 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 42 of 47

Figure 2-6. Radioactivity from reactors (Oldenkamp and Mills 1991).

Performance of a criticality test generates the same types of radioactivity as operation of a reactor, 

but in extremely small amounts. A criticality test operates at a very low power level (up to a few 

hundred watts), and neutron levels are correspondingly very low. Therefore, a large number of 

criticality tests can occur in the same test facility without generating much activation product 

radioactivity. Almost the entire amount of generated radioactivity is contained within the fuel elements 

of the criticality test. When these are removed, the radioactivity is removed. There have been dozens 

of criticality tests at Area IV in seven different facilities (i.e., SNAP Critical Facilities (2), SNAP 

Transient Test Facility, OMR, SGR, AETR, and the Fast Critical Experiment Laboratory). 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 43 of 47

2.4.3 Manufacture of Reactor Fuel Assemblies

The SRE fuel elements were assembled in the Engineering Test Building (Building 4003) from 

uranium and thorium metal slugs made off the site. The slugs were loaded into metal tubes, the 

interstices were filled with sodium metal, and the tubes were sealed. Fuel elements for three cores 

were prepared, but only two were used. The third core was eventually shipped off the site. 

The NMDF (Building 4055) was built specifically for development work involving plutonium. It was 

operated with releases below the effluent limits until 1979.

The uranium carbide fuel manufacturing pilot plant was a small-scale production facility built in 

Building 4005 to study the operations associated with manufacturing reactor fuel assemblies from 

uranium carbide. Operations were completed in about 9 months in 1967, and production was small. 

The Fuel Storage Facility (Building 4064) was a vault built to provide secure storage for fissionable 

fuel material (enriched uranium and plutonium) used to make reactor fuel. 

2.4.4 Disassembly and Examination of Reactors and Used Reactor Fuel Assemblies

Disassembly and examination of reactor fuel assemblies and other test specimens occurred remotely 

in the heavily shielded Hot Lab (Building 4020) built at the SSFL for that purpose. The disassembly, 

fuel removal, and size reduction operations usually involved working with highly radioactive materials. 

The Hot Lab was also used to disassemble or separate the radioactive material from its cladding, and 

the separated materials then shipped away. In addition, the Hot Lab was used to manufacture sealed 

sources, for leak checks on sources, and for cutting and machining operations on 60Co. 

During normal operation, workers on the cold side of the hot cells primarily received external radiation 

from the radioactive materials inside the hot cell shielded by the shield walls and windows. In general, 

the design basis for the shield wall and window was to attenuate the direct radiation to a dose rate of 

0.5 mrem/hr at the surface of the shield walls or windows. 

2.4.5 Fabrication, Use, and Storage of Radioactive Sources

Radiation sources were used to calibrate nuclear instruments and for some forms of radiography, 

irradiation testing, and other applications. Sources were manufactured in the Hot Lab and used in 

various facilities at the SSFL and elsewhere. Approximately 140,000 Ci of radioactive material 

(primarily 147Pm) were fabricated into sources at the Hot Lab. They were stored in secured locations 

and used under carefully controlled conditions. There are currently less than 100 Ci of sources stored 

at the SSFL. 

2.4.6 Preparation of Radioactive Material for Disposal

Radioactive waste was prepared for disposal primarily at the RMDF with support operations at the 

ISF. The RMDF was built and used for fuel storage and processing solid and liquid waste for disposal 

in conjunction with the operation of the SRE. It has since been used to support all of the SSFL 

nuclear operations. The ISF was built to store SRE fuel elements in 10 thimbles installed in holes 

drilled in bedrock, and it was used for storage of fuel shipping casks for other reactors (OMRE and 

SNAP). 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 44 of 47

2.4.7 Research on Reprocessing Used Reactor Fuel 

Tests occurred at the SSFL for the development of a reactor fuel reprocessing process in the wellshielded Hot Cave in Building 4003, the Engineering Test Building. These experiments used up to 

kilogram quantities of unirradiated uranium and thorium, and up to 100-g quantities of highly irradiated 

materials. In general, the design basis for the shield wall and window was to attenuate the direct 

radiation to a dose rate of 0.5 mrem/hr at the surface of the shield walls or windows. 

2.4.8 Operation of Particle Accelerators

Rockwell operated a Van de Graaff generator in Building 4030 to bombard tritium targets with 

deuterons to produce neutrons. A second Van de Graaff generator operated at the SRE facility to 

generate neutrons for neutron activation analyses of materials. 

2.4.9 Research Using Radioisotopes

The TRUMP-S program required the use of radioisotopes as described in Section 2.2.1.3.7. The 

program used small quantities of transuranic materials: 75 g of depleted uranium, 5 g of plutonium, 4 

g of neptunium, and 4 g of americium were ordered for the TRUMP-S program. All of these materials 

were received and initially stored in Building 4064, but the material was shipped to the University of 

Missouri when the program transferred there. 

Another radioisotope research program was a corrosion test program in the Corrosion Testing 

Laboratory (Building 4023). The laboratory was used to study the deposition behavior of activation 

products (54Mn and 60Co) in flowing sodium to develop more effective traps for these isotopes. An 

activated piece of fuel cladding containing these isotopes was used in these tests. 

2.5 MAJOR INCIDENTS 

Table 2-6 describes major site incidents that might have significant potential for internal or external 

exposure to personnel. 

2.6 RADIOLOGICAL ACCESS CONTROLS 

Each specific facility or building in which nuclear operations were conducted at the SSFL site was 

designated as Radiological Control Area. Entry to those areas was controlled. 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 45 of 47

Table 2-6. Major incidents. 

Location/facility Description

Water Boiler 

Neutron Source 

(WBNS)

Building 4093

On March 25, 1959, one of the instruments that controlled the power of the AE-6 malfunctioned and 

allowed the reactor to exceed the normal power level of 3 kWt and to approach 4 kWt. As soon as 

the power level was recognized, the reactor was shut down by the operator. The operation at the 

higher power level lasted only 1 minute. A small amount of fission gas was released when an 

operational error occurred during the transfer of gases (oxygen and hydrogen from the radiolytic 

decomposition of the water in the fuel) from the reactor vessel to a holding tank. It is estimated that 

the maximum release was less than 10 mCi, principally Xe-135. The building volume was sufficient 

to dilute the activity to a concentration essentially equal to that permitted by regulation for 

continuous 40-hr/week exposures. The contamination was cleaned up quickly and effectively, and 

there were no measurable radiation exposures to any of the personnel involved. Corrective action 

was taken, and there were no further incidents of any consequence.

Sodium Reactor 

Experiment (SRE)

Building 4143

The reactor underwent an accidental partial blockage of sodium coolant in some reactor coolant 

channels in July 1959. This resulted in the partial melting of several of the reactor fuel assemblies 

and the release of some fission products that contaminated the reactor cooling system. All of the 

reactor safety systems functioned properly, and the reactor was safely shut down. The reactor fuel 

assemblies were then removed, inspected, and stored at the RMDF. (They were later declad in the 

Hot Lab, and the fuel and cladding was shipped off the site.) A second fuel loading was inserted, 

and the test operations were continued.

Two of the fission products released from the damaged fuel elements were Xe-135 and Kr-85. 

These inert gases contaminated the protective reactor cover gas system. The cover gas was 

transferred to a holding tank and held long enough for the Xe-135 to decay away (9.2-hr half-life) 

and then released to the atmosphere through the stack in a controlled manner in concentrations 

which met AEC requirements. Based on measurements of the cover gas concentration and 

volume, less than 5 Ci of Kr-85 (10.8-yr half-life) were released in this way. The dispersion of the 

Kr-85 in the atmosphere diluted it so much that it would have resulted in a maximum theoretical 

calculated dose of 0.06 μrem to someone living in Susana Knolls, the nearest residential area at 

that time. The other fission products were retained in the primary sodium coolant and were 

removed during cleanup operations. About 54,950 lb of bulk primary sodium were drained into 158 

55-gal drums that were shipped to Hanford, Washington, for storage and possible use in the Fast 

Flux Test Facility. Residual sodium was reacted with alcohol and the solution mixed with 

diatomaceous earth in 55-gal drums that were shipped to Beatty, Nevada, for permitted burial.

SNAP 8 

Experimental 

Reactor (S8SR)

Building 4010

During operation of the S8ER some cracks developed in the cladding that separated the zirconiumuranium alloy fuel from the NaK coolant. The cracks were the result of fuel swelling that stretched 

the cladding beyond its ductility limit. Some fission products diffused out of the fuel and found their 

way into the flowing NaK through the cracks in the cladding. There was no melting of the fuel or 

cladding. All of the fission products were completely contained within the reactor system.

SNAP 8 

Development 

Reactor (S8DR)

Building 4059

As with the S8ER, cladding cracks due to fuel swelling and low cladding ductility occurred during 

the operation of the S8DR. There was no melting of the fuel or the cladding, and all fission 

products were contained in the reactor system.

The activated below-grade part of the facility was kept sealed and periodically inspected. An 

inspection in 1983 disclosed that groundwater was leaking into the reactor vault and becoming 

contaminated. Action was taken immediately to remove the contaminated water, process it, and 

dispose of it, and to begin a pumping program to ensure that radioactive water did not leak out of 

the cell. The leak was found and sealed, and the situation was stabilized.

Hot Lab

Building 4020

On May 19, 1971, a fire occurred in the process of attempting to dispose of about 100 gal of NaK. 

The NaK contained about 100 Ci of mixed fission products. The fire was started upon loss of 

containment of the NaK when a hole was drilled in the tank fill line. Approximately 25 gal of NaK 

were released into the decontamination cell and burned. The normal facility high-volume ventilation 

system that draws all building air through HEPA filters confined essentially all combustion products 

to the Hot Lab.

A radioactive source containing 1.57 mCi of Sr-90 was missing from the Hot Lab in January 1986. 

An investigation concluded that it was inadvertently included in radioactive waste during a cleanup 

and shipped off the site and disposed of as radioactive waste.

Radioactive 

Materials Disposal 

Facility (RMDF)

The septic tank leach field was accidentally contaminated by a dilute solution of fission products 

(primarily cesium and strontium) in 1962 due to the inadvertent opening of a valve in a liquid waste 

system. The valve was removed, and the leach field was cleaned up and released for unrestricted 

use. There was also a small amount of radioactive contamination on the north slope of the hill 

below the facility that was cleaned up.
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 46 of 47

REFERENCES 

Barnes, J. G., 1999, Internal Dosimetry Technical Basis Document and Procedure, RS-00007, The 

Boeing Company, Canoga Park, California, October 28. 

Glasstone, S., and A. Sesonske, 1981, Nuclear Reactor Engineering, 3rd Edition. 

NIOSH (National Institute for Occupational Safety and Health), 2002, Internal Dose Reconstruction 

Implementation Guideline, OCAS-IG-002, Rev. 0, Office of Compensation Analysis and 

Support, Cincinnati, Ohio. 

Oldenkamp, R. D., and J. C. Mills, 1991, Nuclear Operations at Rockwell’s Santa Susana Field 

Laboratory - A Factual Perspective, N001ER000017, Rev. C, Rockwell International, Canoga 

Park, California. 

ORAU (Oak Ridge Associated University), 2005, DOE Technical Basis Documents and Site Profile 

Development, Review, and Approval Process, ORAUT-PROC-0031, Rev. 01-B, Oak Ridge, 

Tennessee, September 13.

RSIC (Radiation Shielding Information Center), 1987, ORIGEN2, Isotope Generation and Depletion 

Code, Oak Ridge National Laboratory, Oak Ridge, Tennessee, November. 

Sapere Consulting, Inc., and The Boeing Company, 2005, Historical Site Assessment of Area IV 

Santa Susana Field Laboratory Ventura County, California, May, Santa Susana Field 

Laboratory Ventura County, California. 

Shleien, B., L. A. Slaback, and B. K. Birky, editors, 1998, Handbook of Health Physics and 

Radiological Health, Third Edition, Williams and Wilkins, Baltimore, Maryland. 
Document No. ORAUT-TKBS-0038-2 Revision No. 00 Effective Date: 02/02/2006 Page 47 of 47

GLOSSARY 

criticality 

A state at which the nuclear chain reaction is sustained due to neutrons generated by fission 

of the fissile material balance the neutrons used up and lost. (keff=1) 

criticality test facility 

Criticality in reactors can be achieved in several ways such as by bringing parts of a core of 

fissionable material together (to reduce the number of neutrons that escape) or by removing 

control rods (to reduce the number of neutrons captured in the control rods). Criticality test 

facility is used to evaluate and develop parameters for reactor to achieve criticality for a variety 

of reactor core materials, moderators and reflectors. 

curie (Ci) 

Traditional unit of radioactivity equal to 37 billion (3.7 x 1010) becquerels, which is 

approximately equal to the activity of 1 gram of pure 226Ra. 

rem 

Traditional unit of radiation dose equivalent that indicates the biological damage caused by 

radiation equivalent to that caused by 1 rad of high-penetration X-rays multiplied by a quality 

factor. The average American receives 360 millirem a year from background radiation. The 

sievert is the International System unit; 1 rem equals 0.01 sievert. The word derives from 

roentgen equivalent in man; rem is also the plural.