ORAU TEAM

Dose Reconstruction

Project for NIOSH

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

Page 1 of 97

Document Title:

Nevada Test Site – Site Description

Document Number: ORAUT-TKBS-0008-2 

Revision: 01

Effective Date: 10/01/2007

Type of Document TBD

Supersedes: Revision 00

Subject Expert(s): Eugene M. Rollins

Site Expert(s): N/A 

Approval: Signature on File Approval Date: 09/27/2007

Eugene M. Rollins, Document Owner 

Concurrence: Signature on File Concurrence Date: 09/28/2007

John M. Byrne, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 09/27/2007

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Concurrence Date: 09/27/2007

Kate Kimpan, Project Director

Approval: Brant A. Ulsh Signature on File for Approval Date: 10/01/2007

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-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 2 of 97

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

02/02/2004 00 New technical basis document for the Nevada Test Site – Site 

Description. First approved issue with the restriction that states, 

“Nevada Test Site incidents are to be included in future revisions of 

the Nevada Test Site Technical Basis Documents.” Incorporates 

formal internal and NIOSH review comments. Initiated by Eugene M. 

Rollins.

10/01/2007 01 Approved Revision 01 initiated as a result of the biennial document 

review. Constitutes a total rewrite of document. This revision 

includes expanded details as to activities and project timeframes at 

the NTS. General information about access control has been added. 

New attachments include an enumeration of tests by year, type, and 

location; a description of nuclear rocket and ramjet tests; an 

evaluation of exposure potential by contractor job title; and a 

discussion of post-test drilling technology. Incorporates formal 

internal and NIOSH review comments. Training required: As 

determined by the Task Manager. Initiated by Eugene M. Rollins. 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 3 of 97

TABLE OF CONTENTS

SECTION TITLE

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

PAGE

7

2.1 Introduction ...............................................................................................................................10

2.1.1 Purpose........................................................................................................................ 11

2.1.2 Scope........................................................................................................................... 11

2.2 Site Activities and Facilities.......................................................................................................11

2.2.1 Area 1 Nuclear Test Zone ............................................................................................ 12

2.2.2 Area 2 Nuclear Test Zone ............................................................................................ 14

2.2.3 Area 3 Nuclear Test Zone and Radioactive Waste Management Site......................... 14

2.2.4 Area 4 Nuclear Test Zone ............................................................................................ 15

2.2.5 Area 5 Radioactive Waste Management Site and Spill Test Zones............................. 15

2.2.6 Area 6 Nuclear Test Zone ............................................................................................ 16

2.2.7 Area 7 Nuclear Test Zone ............................................................................................ 18

2.2.8 Area 8 Nuclear Test Zone ............................................................................................ 18

2.2.9 Area 9 Nuclear Test Zone ............................................................................................ 18

2.2.10 Area 10 Nuclear Test Zone .......................................................................................... 18

2.2.11 Area 11 Nuclear Test and Reserved Zone................................................................... 19

2.2.12 Area 12 Nuclear or HE Test Zone................................................................................ 19

2.2.13 Area 13 Nellis Test and Training Range Complex ....................................................... 20

2.2.14 Area 14 Reserved Zone ............................................................................................... 20

2.2.15 Area 15 Reserved Zone ............................................................................................... 20

2.2.16 Area 16 Nuclear or HE Test Zone................................................................................ 21

2.2.17 Area 17 Reserved Zone ............................................................................................... 21

2.2.18 Area 18 Reserved Zone ............................................................................................... 21

2.2.19 Area 19 Nuclear Test Zone .......................................................................................... 22

2.2.20 Area 20 Nuclear Test Zone .......................................................................................... 22

2.2.21 Area 21......................................................................................................................... 22

2.2.22 Area 22 Reserved Zone ............................................................................................... 22

2.2.23 Area 23 Reserved Zone ............................................................................................... 23

2.2.24 Area 24......................................................................................................................... 23

2.2.25 Area 25 Yucca Mountain Project, Reserved, and Research and 

Experiment Zones ........................................................................................................ 24

2.2.26 Area 26 Reserved Zone ............................................................................................... 25

2.2.27 Area 27 Critical Assembly Zone................................................................................... 26

2.2.28 Area 28......................................................................................................................... 26

2.2.29 Area 29 Reserved Zone ............................................................................................... 26

2.2.30 Area 30 Reserved Zone ............................................................................................... 27

2.2.31 Nellis Test and Training Range.................................................................................... 27

2.3 Site Operations and Processes ................................................................................................27

2.3.1 Atmospheric Weapons Testing .................................................................................... 28

2.3.2 Safety Tests and Contaminated Surface Soils............................................................. 35

2.3.3 Underground Tests ...................................................................................................... 38

2.3.3.1 Tests in Vertical Drill Holes and Drill Backs .....................................................38

2.3.3.2 Tests in Mined Tunnels and Mine Backs .........................................................40

2.3.3.3 U1a Subcritical Experiments............................................................................41
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2.3.3.4 Shallow Borehole Tests ...................................................................................42

2.3.3.5 Radioactive Releases from Nuclear Weapons Testing....................................42

2.3.4 Nuclear Reactor Development Tests ........................................................................... 45

2.3.5 Radioactive Waste Management Sites ........................................................................ 46

2.3.5.1 Crater Disposal – Area 3..................................................................................46

2.3.5.2 Shallow Land Burial – Area 5 Low-Level .........................................................46

2.3.5.3 Greater Confinement Disposal – Area 5..........................................................47

2.3.6 Laboratories ................................................................................................................. 47

2.3.7 Radiograph Operations ................................................................................................ 48

2.3.8 Well-Logging Operations.............................................................................................. 48

2.3.9 Treatability Test Facility ............................................................................................... 48

2.3.10 Decontamination Facility .............................................................................................. 48

2.3.11 Radiation Instrument Calibration Facilities................................................................... 49

2.3.12 Radioactive Source Storage Areas .............................................................................. 49

2.3.13 Nuclear Explosive Assembly and Device Assembly Facility ........................................ 49

2.4 Radiological Access Controls ...................................................................................................49

2.5 Attributions and Annotations .....................................................................................................50

References ...........................................................................................................................................51

Glossary................................................................................................................................................54

ATTACHMENT A, TEST BY YEAR, TYPE AND LOCATION............................................................. 59

ATTACHMENT B, NUCLEAR ROCKET AND RAMJET ENGINE TESTS ......................................... 62

B.1 Introduction ...............................................................................................................................62

B.2 Area 400 Major Facilities ..........................................................................................................62

B.3 ROVER .....................................................................................................................................65

B.3.1 Project Reactor and Engine Tests ............................................................................... 67

B.4 PLUTO......................................................................................................................................70

B.4.1 Area 401 Major Facilities.............................................................................................. 70

B.4.2 TORY Reactor Tests.................................................................................................... 71

B.5 Summary of Radiological Hazards............................................................................................73

B.5.1 External Exposure........................................................................................................ 73

B.5.2 Internal Exposure......................................................................................................... 73

B.6 Onsite Radiological Support for Reactor Tests.........................................................................73

ATTACHMENT C, NTS CONTRACTOR JOB TITLES AND EXPOSURE POTENTIAL 

REVIEW ................................................................................................................ 77

C.1 REECo......................................................................................................................................77

C.2 Other Contractors (EG&G Energy Measurements, H&N, and RSN) ........................................78

C.3 Current and Former NTS Contractors.......................................................................................78

C.4 Job Title References .................................................................................................................78

ATTACHMENT D, POST-TEST DRILLING TECHNOLOGY AND RADIATION 

EXPOSURE POTENTIAL..................................................................................... 84

D.1 Post-Test Drilling Techniques ...................................................................................................84

D.2 Radioactivity Releases and Personnel Exposure .....................................................................89
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D.3 Core Sampling ..........................................................................................................................92

D.4 Radioactivity Control Measures ................................................................................................92

D.5 Post-Test Radiation Monitoring................................................................................................. 94

D.6 Exposed Workers......................................................................................................................96

LIST OF TABLES

TABLE TITLE

2-1 Nuclear weapons test timeline..................................................................................................

PAGE

28

2-2 Radionuclides of concern for various NTS activities................................................................. 29

2-3 Radionuclides typically deposited after atmospheric tests for various time 

intervals.....................................................................................................................................32

2-4 Radioactivity on the NTS, January 1996...................................................................................36

2-5 Releases from underground tests (normalized to 12 hr after event).........................................43

2-6 Estimated curies emitted from the source for 2001 ..................................................................47

A-1 Tests by year, type, and location ..............................................................................................59

A-2 NTS testing intervals.................................................................................................................61

B-1 Radionuclides found in effluent clouds from nuclear rocket and ramjet 

engine tests...............................................................................................................................74

B-2 Summary of tests of nuclear-powered rocket and ramjet engines which 

generated radioactive effluent detected off the site ..................................................................75

C-1 REECo job titles that probably had some potential for workplace external 

and/or internal exposures .........................................................................................................79

C-2 REECo job titles that possibly had some potential for workplace external 

and/or internal exposures .........................................................................................................81

C-3 Other contractor job titles with some potential for workplace internal and/or 

external exposure .....................................................................................................................83

D-1 Hycalog nomenclature ..............................................................................................................89

D-2 Primary fission product noble gases with half-lives greater than 1 hr (for 

yields equal to or greater than 0.01 photon or beta per disintegration) ....................................90
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LIST OF FIGURES

FIGURE TITLE

2-1 NTS areas, principal facilities, and testing area........................................................................

PAGE

13

B-1 Details of nuclear propulsion sites ............................................................................................63

B-2 Nuclear Rocket Development Station.......................................................................................64

B-3 Chronology of major nuclear rocket tests .................................................................................66

B-4 Reactors for ground-based systems tests ................................................................................66

B-5 Nuclear rocket engine configurations........................................................................................67

B-6 Schematic diagram of TORY II-C reactor on vehicle flatcar .....................................................72

D-1 Three methods of post-test drilling............................................................................................85

D-2 Schematic of a rotary drilling rig................................................................................................86

D-3 Schematic of a standard vertical test rig...................................................................................87

D-4 Hycalog drill rig .........................................................................................................................88

D-5 Circulation of drilling fluid..........................................................................................................91

D-6 Four steps in taking a sidewall sample .....................................................................................93

D-7 Blowout preventer.....................................................................................................................93
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 7 of 97

ACRONYMS AND ABBREVIATIONS

AEC U.S. Atomic Energy Commission

Anti-C anticontamination

BEEF Big Explosives Experimental Facility

BN Bechtel Nevada

BOP blowout preventer

BREN Bare Reactor Experiment Nevada

cfm cubic feet per minute

Ci curie 

cm centimeter

CP Control Point

cpm counts per minute

d day

DAF Device Assembly Facility

decon decontamination

DNA Defense Nuclear Agency

DOD U.S. Department of Defense

DOE U.S. Department of Energy

DSWA Defense Special Weapons Agency

DTRA Defense Threat Reduction Agency

EG&G Edgerton, Germeshausen, and Grier

EIS environmental impact statement

E-MAD Engine Maintenance Assembly and Disassembly

EPA U.S. Environmental Protection Agency

°F degrees Fahrenheit

FSN Fenix & Scisson of Nevada

ft foot

g gram

GMX Gadgets, Mechanics, and Explosives (former division of Los Alamos National 

Laboratory)

H&N Holmes & Narver

HAZMAT hazardous material

HE high explosive

HLOS horizontal line of sight

hr hour

in. inch

INC Isotope and Nuclear Chemistry

JASPER Joint Actinide Shock Physics Experimental Research

°K degrees Kelvin

keV kilovolt-electron, 1,000 electron volts

kg kilogram
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 8 of 97

km kilometer

kps kilometers per second

kt kiloton (explosive force of 1,000 tons of TNT)

LANL Los Alamos National Laboratory

LASL Los Alamos Scientific Laboratory

lb pound

LLNL Lawrence Livermore National Laboratory

LOS line of sight

LRL Lawrence Radiation Laboratories

LYNER Low-Yield Nuclear Explosive Research

m meter

MAD Maintenance, Assembly, and Disassembly

mCi microcurie 

mi mile

min minute

ml milliliter

mph miles per hour

mR milliroentgen

ms millisecond

Mt megaton (explosive force of 1 million t TNT)

MW megawatt

NASA National Aeronautics and Space Administration

NEAF Nuclear Explosive Assembly Facility 

NERVA Nuclear Engine for Rocket Vehicle Application

NIOSH National Institute for Occupational Safety and Health

NNSA National Nuclear Security Administration

NRDS Nuclear Rocket Development Station

NSO Nevada Site Office

NTS Nevada Test Site

NTTR Nellis Test and Training Range

NUWAX Nuclear Weapons Accident Exercise

PPC personal protective clothing

psi pounds per square inch

R roentgen

RAM remote air monitoring

RCRA Resource Conservation and Recovery Act

REECo Reynolds Electrical and Engineering Company

RER Radiological Emergency Response

RMAD Reactor Machine Assembly and Disassembly

RSN Raytheon Services Nevada

RWMS Radioactive Waste Management Site

s second

SNM Special Nuclear Material

SOP standard operating procedure
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t ton [explosive force of 1 t (2,000 lb) TNT]

TAPS tunnel and pipe seal

TED track etch dosimeter

TLD thermoluminescent dosimeter

TNT trinitrotoluene

TRU transuranic

TTR Tonopah Test Range

U.S.C. United States Code

WEF Waste Examination Facility

WIPP Waste Isolation Pilot Plant

WSI Wackenhut Services, Inc.

XE Experimental Engine

yr year

μCi microcurie 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 10 of 97

2.1 INTRODUCTION

Technical basis documents and site profile documents are not official determinations made by the 

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

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

dose reconstructions for 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 NIOSH staff 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 POC [probability of causation1

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 occupationally derived radiation 

exposures at covered facilities 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 monitoring 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. NIOSH, however, does not consider the following exposures to be occupationally 

derived:

] 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.

• Radiation from naturally occurring radon present in conventional structures

• Radiation from diagnostic X-rays received in the treatment of work-related injuries

 

1 The U.S. Department of Labor is ultimately responsible under the EEOICPA for determining the POC. 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 11 of 97

2.1.1

The purpose of this section of the NTS Site Profile is to provide background information on the site 

and its historical activities to the dose reconstructor.

Purpose

2.1.2

The scope of this section of the NTS Site Profile is to describe the site in relation to possible sources 

of radioactive contamination from site activities and facilities (Section 2.2) and site processes 

(Section 2.3) and provide an overview of radiological access controls (Section 2.4). The attachments 

include an enumeration of tests by year, type, and location; a description of nuclear rocket and ramjet 

tests; an evaluation of exposure potential by contractor job title; and a discussion of post-test drilling 

technology.

Scope

2.2 SITE ACTIVITIES AND FACILITIES

The Nevada Test Site (NTS) in southern Nevada has served as the Nation’s primary continental test 

site for the development of nuclear explosives. The NTS currently encompasses approximately 3,500 

km2 (1,375 mi2

); it is surrounded on the east, west, and north by the Nellis Test and Training Range 

(NTTR; formerly the Nellis Air Force Range), which provides a 24- to 100-km (15- to 64-mi) buffer 

zone between the NTS border and public lands. Included within the NTTR and to the northwest of the 

NTS is the Tonopah Test Range (TTR). The U.S. Bureau of Land Management administers Federal 

lands on the southern and southwestern borders of the NTS. Las Vegas, the major metropolitan 

center closest to the NTS, is approximately 105 km (65 mi) southeast of the site. Residential 

locations within 48 km (30 mi) of the NTS boundary are Indian Springs in Clark County and Pahrump 

and Beatty in Nye County. Other surrounding cities with sparse population within 48 km of the NTS 

are Rachel, Scotty’s Junction, Rhyolite, Amargosa Valley, Johnnie, and Cactus Springs in Nevada; 

and Furnace Creek Ranch and Death Valley Junction in California.

The U.S. Department of Energy, National Nuclear Security Administration (NNSA), Nevada Site Office 

(NSO), operates the NTS, which is divided into the following seven zone categories as described in 

DOE (1996a): 

1. Nuclear Test Zone – Land area reserved for underground hydrodynamic tests, dynamic 

experiments, and underground nuclear weapons and weapons effects tests. The stockpile 

stewardship emplacement hole inventory is in this zone. Part of the mission of the Stockpile 

Stewardship Program is to reserve land and infrastructure for next-generation nuclear 

weapons simulators pending programmatic decisions.

2. Nuclear and High Explosive (HE) Test Zone – Area designated for additional underground 

and aboveground HE tests or experiments.

3. Research, Test, and Experiment Zone – Area designated for small-scale research, 

development, and pilot projects and outdoor tests and experiments for the development, 

quality assurance, or reliability of materials and equipment under controlled conditions.

4. Radioactive Waste Management Zone – Area designated for the shallow land burial of 

low-level and mixed wastes.
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5. Critical Assembly Zone – Area used for nuclear explosive operations, which generally 

include assembly, disassembly or modification, staging, repair, retrofit, and surveillance. This 

zone could also be used for weapons storage.

6. Spill Test Facility Impact Zone – A downwind geographic area that would confine the effects 

of the largest planned tests of materials released at the Hazardous Material (HAZMAT) Spill 

Center (formerly the Spill Test Facility).

7. Reserved Zone – Controlled-access area that provides a buffer between non-defense related 

research, development, and testing activities. The Reserved Zone includes areas and 

facilities that provide widespread flexible support for diverse short-term non-defense related 

research, testing, and experimentation. In addition, this zone is used for short-duration 

exercises and training, such as Nuclear Emergency Support Team and Federal Radiological 

Monitoring and Assessment Center training, both part of DOE, and U.S. Department of 

Defense (DOD) land navigation exercises and training.

Each numbered area on the NTS is associated with one or more of these zones. Figure 2-1 shows 

the numbered areas, principal facilities, and testing areas. Attachment A shows the NTS tests by 

year, type, and location and the intervals between NTS tests. The following sections describe these 

areas and indicate where activities that produced radioactive effluents occurred on the NTS. There is 

no Area 21 or Area 24 at the NTS: Area 21 simply does not exist, and Area 24 is the support facility 

in the Las Vegas metropolitan area. 

The Final Environmental Impact Statement for the Nevada Test Site and Off-site Location in the State 

of Nevada (DOE 1996a) and the United States Nuclear Tests, July 1945 through September 1992 

(DOE 2000a) provided much of the area-specific descriptions in the following sections. In addition, 

Nevada Test Site Contaminated Land Areas Report (DOE 2000b) provided information about past 

contamination, its causes, and current practices such as the use of postings and fences for control of 

contaminated areas. The names of nuclear tests and some programs are in all-capital letters but are 

not necessarily acronyms with meaning. 

DOE was created in 1977. The historical activities described in this document occurred for the most 

part under the authority of DOE or its predecessor agencies (the U.S. Atomic Energy Commission 

(AEC) and the Energy Research Development Administration). In addition, DOD and the Defense 

Special Weapons Agency [DSWA; the Defense Nuclear Agency (DNA) until 1996] supported nuclear 

weapons testing on the NTS. DSWA, which is a descendent of the Manhattan Project, evolved from 

the Armed Forces Special Weapons Project in 1947, to the Defense Atomic Support Agency in 1959, 

to DSWA in 1971. 

2.2.1

Area 1 was the site of five atmospheric nuclear tests between 1952 and 1955 and of three 

underground nuclear tests, one in 1971 and two in 1990. In 1955, as part of the Nation’s Civil 

Defense Program, various types of homes and buildings were constructed to test the effects of a 

nuclear blast and blast overpressures on typical urban structures. A few of these “Survival Town” 

structures still stand. Area 1 is the location of two four-story reinforced concrete structures built for 

structural response investigations. These structures have allowed study of structural response 

characteristics applicable to high-rise buildings.

Area 1 Nuclear Test Zone

In addition, Area 1 contains the U1a mined underground complex, which is available for dynamic 

experiments (including subcritical experiments involving special nuclear material) and HE tests that 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 13 of 97

cannot be conducted atmospherically because they could disperse hazardous materials. The vertical 

shaft is equipped with a mechanical hoist for personnel and equipment access while another vertical 

shaft about 1,000 ft away provides cross ventilation, instrumentation, utility access, and emergency 

egress. On the surface, there are several temporary buildings and instrumentation trailers. 

The U1a facility was previously called the Low-Yield Nuclear Explosive Research (LYNER) Complex. 

The Complex consists of horizontal tunnels about 0.5 mi long mined at the base of a vertical shaft 

approximately 960 ft beneath the surface mined in the late 1960s for an underground nuclear test that 

never occurred. In 1988, the shaft was reopened, and a 1,460-ft horizontal tunnel was mined south at 

the 962-ft level of the shaft. The LEDOUX nuclear test, with a yield of less than 20 kt, was conducted 

in 1990 in a drift in this tunnel complex. 

Frenchman

Flat

Figure 2-1. NTS areas, principal facilities, and testing area 

(DOE 1997a). 

Further work took place in the 1980s and early 1990s to develop U1a for experiments likely to remain 

subcritical. The dynamic KISMET experiment, involving HE, tritium, depleted uranium, and other 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 14 of 97

materials, was conducted in March 1995. Both LEDOUX and KISMET were contained to prevent 

radiological releases to the rest of the Complex and the surface environment. 

The subcritical experiments are integrated systems tests of mock-up nuclear packages calling for 

explosion of the conventional HE portion and measurement of the resultant motions and reactions of 

materials and components. These tests obtain diagnostic information on the behavior of a nuclear 

weapons primary assembly using stockpile material and evaluate the effects of aging on nuclear 

weapons in the Nation’s arsenal. Subcritical experiments began in 1997 and continue today.

2.2.2

This area in the Nuclear Test Zone occupies approximately 52 km2 (20 mi2

) in the northern half of the 

Yucca Flat basin. The eastern portion of Area 2 was the site of seven atmospheric nuclear tests 

between 1952 and 1957. A series of underground nuclear tests in Area 2 began in late 1962 and 

continued through 1990. A number of the 137 underground tests were simultaneous detonations of 

multiple devices in the same emplacement hole; other underground tests involved the firing of two or 

more devices in separate emplacement holes. NTS moved most of the structures in a former 

construction base camp (Butler buildings, Quonset huts, trailers, etc.) to Area 6. The remaining 

facilities were moved to other locations or disposed.

Area 2 Nuclear Test Zone

2.2.3

This portion of the Nuclear Test Zone occupies 83 km2

 (32 mi2) near the center of the Yucca Flat 

weapons test basin. It was the site of 14 atmospheric tests between 1952 and 1958. There were 252 

underground nuclear tests in Area 3 from 1958 to 1992, which was the largest number of tests in any 

NTS underground test area. A number of these tests consisted of simultaneous device detonations, 

and nearly all of the simultaneous tests consisted of single devices in separate emplacement holes. 

Between mid-1957 and late 1958, nine underground nuclear tests in Area 3 occurred in unstemmed 

holes to minimize, but not eliminate, releases of radioactivity to the atmosphere. Area 3 contains 

numerous posted areas.

Area 3 Nuclear Test Zone and Radioactive Waste Management Site

Area 3 contains numerous circular subsidence craters formed by the collapse of deep underground 

spherical cavities formed by nuclear explosions. The earth collapses as the gases inside the test 

cavity cool and outward pressures decline. The collapse progresses upward from the cavity to the 

ground surface, which results in the formation of a subsidence crater. The BILBY test in the fall of 

1963 (approximately 249 kt) was one of the largest detonations ever conducted in the Yucca Flat 

basin, and it was the first underground test to be felt by a large number of Las Vegas residents. 

BILBY was fired 732 m (2,400 ft) underground in volcanic rock and resulted in one of the largest 

subsidence craters at the test site, which measures 1,800 ft (549 m) in diameter and 24 m (80 ft) 

deep. This crater is on a public tour route. The crater bottom contains a capped borehole.

NTS disposes of bulk low-level waste in seven Area 3 subsidence craters that collectively make up 

the Area 3 Radioactive Waste Management Site (RWMS). This activity began in the mid-1960s with 

the beginning of removal of scrap tower steel, vehicles, and other large objects subjected to 

atmospheric testing. From 1979 to 1990, large amounts of contaminated soil and other debris from 

the NTS were added to the craters.

There are four stockpile stewardship emplacement holes in Area 3. NTS has moved most of the 

structures in a former construction base camp (Butler buildings, Quonset huts, trailers, etc.) to Area 6. 

Remaining facilities were moved to other locations or disposed.
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 15 of 97

2.2.4

This area in the Nuclear Test Zone occupies 41 km2 (16 mi2

) near the center of the Yucca Flat basin. 

Area 4 was the site of five atmospheric nuclear tests between 1952 and 1957. From the mid-1970s 

through 1991, there were 35 underground nuclear tests in Area 4, mainly in the northeast corner. 

Two of these tests involved the simultaneous detonation of multiple devices in the same emplacement 

hole. There are four stockpile stewardship emplacement holes in Area 4.

Area 4 Nuclear Test Zone

The Big Explosives Experimental Facility (BEEF) in Area 4 was designed as an operational complex 

for testing large conventional non-nuclear HE charges weighing as much as several thousand or more 

kilograms. The need for the BEEF site originated when, due to community encroachment near the 

Lawrence Livermore National Laboratory (LLNL) in Livermore, California, DOE was no longer allowed 

to perform large HE experiments at that facility’s Site 300 under the Shaped Charge Scaling Project. 

Therefore, DOE looked at the NTS as a location to continue to perform these large HE experiments 

and chose two earth-covered, 2-ft-thick steel-reinforced concrete bunkers (built to monitor 

atmospheric tests at Yucca Flat in the 1950s).

The facility consists of a control bunker, a camera bunker, a gravel firing table, and associated control 

and diagnostic systems. The facility has conducted conventional HE experiments using a test bed 

that provides sophisticated diagnostics such as high-speed optics and X-ray radiography on the firing 

table, while operating personnel are present in the bunker.

The POPOVER test series was conducted in 1995 to demonstrate that large conventional HE 

experiments could be safely conducted while operating personnel were present in the control bunker. 

The test data was used to develop an effects profile that defined the relationship of the HE charge 

size and detonation point to blast effects such as overpressure, bunker wall strain, dynamic response 

(acceleration), and noise amplitude.

2.2.5

This area in the Reserved Zone occupies about 246 km2 (95 mi2

) in the southeastern portion of the 

site. It includes the Area 5 RWMS, the Hazardous Waste Storage Unit, the HAZMAT Spill Center, the 

Transuranic (TRU) Pad Cover Building, and the Waste Examination Facility (WEF). The WEF houses 

a large multilevel glovebox used to examine legacy and national laboratory waste, to separate and 

segregate Resource Conservation and Recovery Act (RCRA) material, and to repack TRU waste for 

shipment to the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico. The original and 

repacked containers are stored in the TRU Pad Cover Building. Operations in WEF have the potential 

for internal exposure if a breach in the glovebox barrier occurs.

Area 5 Radioactive Waste Management Site and Spill Test Zones

From 1951 to early 1962, there were 14 atmospheric tests at Frenchman Flat, several of which were 

weapons effects tests. Among the remains of the structures tested in Frenchman Flat are simulated 

motel complexes, metal frames that supported a variety of roofing materials, a window test structure, 

cylindrical liquid storage vessels, reinforced concrete domes, aluminum domes, bridge pedestals, and 

a bank vault, all of which are of considerable historic interest. 

Twenty-four experiments occurred between 1954 and 1956 in the Gadgets, Mechanics, and 

Explosives (GMX) project site in Area 5 in which small quantities of plutonium materials were 

subjected to HE detonations (see Section 2.3.2 for additional information on safety tests). Five 

underground nuclear weapons tests occurred at Frenchman Flat between 1965 and 1971. However, 

the presence of a carbonate aquifer makes this area less suitable for underground testing than other 

locations on the NTS.
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A simulated test corresponding to the accidental explosion of HE material in an underground bunker 

(commonly known as a Gravel Gertie) occurred in Area 5 in the 1950s and again in late 1982. This 

structure satisfied tests for containment of the explosion and associated radioactive material. Similar 

designs have been used at the Device Assembly Facility (DAF) in Area 6 and at the Pantex Plant near 

Amarillo, Texas, where DOE has conducted the majority of nuclear weapons assembly and 

disassembly operations.

Area 5 is the permanent home for the HAZMAT Spill Center. By Congressional mandate, use of the 

Spill Center is available to private and public sector test sponsors (i.e., chemical processors and oil 

companies) on a fee basis. The Spill Center (the only facility of its kind in the world) was completed in 

April 1986 as a place to conduct safety research associated with the handling, shipping, and storage 

of liquefied gaseous fuels and other hazardous fluids. The facility is used to release hazardous 

materials for training purposes, field-test detection, plume dispersion experimentation, and equipment 

and materials testing. The facility consists of a complex of fuel tanks, spill pads, meteorological and 

camera towers, assorted equipment arrays, control buildings, and a large-scale wind tunnel. 

One of the primary NNSA/NSO missions has been to provide an ongoing waste management 

program that covers all wastes generated on the NTS as well as wastes from other defense-related 

facilities. Opened in 1961, the Area 5 RWMS is a 296-hectare (732-acre), low-level radioactive waste 

storage and disposal facility. The developed area at the RWMS consists of 22 landfill cells (pits and 

trenches) and 13 greater confinement disposal boreholes. DOE has disposed of mixed waste, 

including transuranic mixed waste, at the NTS in the past and currently stores transuranic wastes in 

Area 5 pending ultimate disposal at WIPP. 

The Hazardous Waste Storage Site in Area 5 is a Nevada-approved NTS-wide accumulation point for 

the collection of RCRA nonradioactive hazardous materials such as paint residues, miscellaneous 

chemicals, unused or surplus fuels, and so forth. Hazardous wastes generated at the NTS are 

periodically sent to licensed offsite commercial facilities for recycling, incineration, or disposal.

2.2.6

This area occupies a 212-km2

 (82-mi2) parcel of land between Yucca Flat and Frenchman Flat 

(straddling Frenchman Mountain). Between 1968 and mid-1990, four underground nuclear tests 

occurred at this location, one of which involved the simultaneous detonation of multiple devices in two 

separate emplacement holes in Area 6 and Area 3. There are two stockpile stewardship 

emplacement holes in Area 6.

Area 6 Nuclear Test Zone

The Control Point (CP) complex serves all NTS user organizations as a centralized point of 

coordination for administrative, scientific, and technical matters. The CP also serves as the 

NNSA/NSO command center, air operations center, and timing and firing center. Support facilities 

include a communications building, several radiological sciences facilities, and technical laboratories. 

In addition, this area contains the Los Alamos National Laboratory (LANL) Mouse House, which 

houses the LANL radiation control facilities in support of U1a Complex activities.

The Area 6 Construction Facilities provide craft and logistical support to activities in the forward areas 

of the NTS. This complex replaces older construction base camps in Areas 2 and 3. The elements of 

the Yucca Lake facilities include a variety of equipment storage facilities, a heavy-duty maintenance 

and equipment repair facility, and decontamination (decon) facilities. Facilities for laundering 

radiologically contaminated clothing were operated here. At the Decon Facility, large pieces of 

equipment were decontaminated. Contaminated liquid waste from decontamination operations was 

discharged through floor drains to large tanks. The yard below these facilities could be contaminated. 
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Contaminated radioactive waste was also stored in a tent structure adjacent to the Decon Facility. A 

3,353-m (11,000-ft) airstrip and nearby weather station are on the dry Yucca Lake bed. 

The DAF is approximately 3 mi (4.8 km) south of the CP complex and was designed to serve as a 

modern, safe, and secure facility for assembling and disassembling nuclear test devices and nuclear 

weapons. The DAF, which replaced and consolidated facilities elsewhere on the NTS, was designed 

to limit explosive overpressures and to contain radioactive materials in the event of an accident. 

Construction began in 1988 and ended in 1990, when equipment installation and related interior work 

began. The DAF is an operational facility that includes glovebox and downdraft table equipment to 

support receipt of material from JASPER. LLNL and LANL jointly operate the DAF. 

The DAF is a collection of more than 30 individual steel-reinforced concrete buildings connected by a 

rectangular common corridor. The entire complex, covered by compacted earth, spans an area of 

100,000 ft2

. Safety systems include fire detection and suppression, electrical grounding, independent 

heating, ventilation and air-conditioning systems with high-efficiency particulate air filters, loudspeaker 

and alarm systems, and warning lights. In operational areas, pairs of blast doors designed to mitigate 

the effects of an explosion are interlocked so that only one door can open at a time. The operational 

buildings in the DAF include five assembly cells, four high bays, three assembly bays (one of which 

houses a glove box and one of which houses a downdraft table), and two radiography bays. Five 

staging bunkers provide space for staging nuclear components and HE.

All materials packages arrive or depart the DAF through one of two shipping or receiving bays. The 

support buildings include three small vaults for staging small quantities of HE or special nuclear 

material, two decontamination areas, and an administration area containing office space, a 

conference area, personnel changing and shower rooms, and a machine shop. In addition, one 

building provides laboratory space for conducting instrumentation and environmental testing and 

another provides for observation of operations in an adjacent assembly cell.

The DAF assembly cells were modeled after the structure at Pantex Plant, where hands-on assembly 

and disassembly of U.S. nuclear weapons takes place. The cells provide maximal environmental and 

personnel protection in the event of an inadvertent HE detonation. The cells are designed to absorb 

the blast pressure from a detonation of up to 192 kg (423 lb) of plastic-based explosives equivalent to 

250 kg or 550 lb of TNT. Should a detonation occur, the Gravel Gertie would minimize the release of 

nuclear material and its spread to other areas of the facility and to outside areas.

The ATLAS pulsed power construction project began in 1995 at LANL, with engineering design and 

component testing. Full-scale assembly began in November 1999 and construction was completed in 

August 2000. In 2001, LANL scientists performed the first pulsed-power driven implosion shot. This 

successful experiment demonstrated the facility’s capability to provide materials data to support the 

certification of the nuclear weapons stockpile. Congress directed that ATLAS be relocated to the NTS 

in 2002. Construction of the new 14,000-ft2 high-bay facility in Area 6 was completed in April 2004 

and electrical testing was completed in July 2005. 

ATLAS consists of high-voltage capacitor banks that discharge electrical energy into a system of 

parallel-plate transmission lines. Large electrical currents flow through the plates to produce an 

intense magnetic field, which applies a huge pressure pulse into a cylindrical liner and target 

containing materials of interest. ATLAS acts as a giant power amplifier, using energy that 

accumulates slowly at 480 volts and is stored in the machine's capacitor banks for sudden release 

into the liner and target. As the current surges through ATLAS, it accelerates materials to velocities 

well in excess of that required to escape Earth’s gravity (as high as 22,000 mph), and generates 

pressures equivalent to millions of times that of Earth's atmosphere. ATLAS can impinge on axial 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 18 of 97

targets with tremendous force to study the shock and compression properties for materials of interest 

to weapons design, manufacturing, and performance. Highly advanced optical and X-ray diagnostic 

equipment measures the properties of the imploding materials. The physical environments produced 

by ATLAS enable a wide range of safe, reproducible, and controllable experiments in areas of basic 

science and civilian technologies that have no significant effects on the environment in an era that 

precludes nuclear weapons testing. The extreme conditions of high-energy density, strongly coupled 

plasmas, and high magnetic fields have potential applications for understanding planetary physics, 

condensed-matter physics, fusion energy research, and astrophysics. The Hydrocarbon 

Contaminated Soils Disposal Site in Area 6 is a Nevada-approved Class III landfill for the disposal of 

all non-RCRA hydrocarbon-contaminated soils and materials from the NTS. 

2.2.7

This area in the Nuclear Test Zone occupies 52 km2 (20 mi2

) in the northeast quadrant of the Yucca 

Flat weapons test basin. Thirty atmospheric tests occurred in this area. From late 1964 to the fall of 

1991, 62 underground nuclear tests occurred in Area 7, each of which consisted of a single nuclear 

device in a drilled emplacement hole. There are three stockpile stewardship emplacement holes in 

Area 7. 

Area 7 Nuclear Test Zone

2.2.8

This area in the Nuclear Test Zone occupies 34 km2 (13 mi2

) in the northeast quadrant of the Yucca 

Flat weapons test basin. Area 8 was the site of four atmospheric nuclear tests in 1958. From 

mid-1966 to late 1988, 10 underground nuclear tests occurred at this location. Two of the 

underground tests involved the simultaneous firing of multiple devices in the same emplacement hole. 

Area 8 Nuclear Test Zone

French- and German-type underground shelter structures were tested in Area 8 in 1957. In 1964, the

University of Florida used these structures for shelter habitability studies. The BANEBERRY test, 

which vented to the atmosphere, occurred here in 1970. Section 2.3.3 provides a description of the 

BANEBERRY test and other tests that resulted in radioactive releases to the environment. The area 

is geographically complex due to the combination of tests, wide-spread debris, steep slopes, and 

wastes. 

2.2.9

This area in the Nuclear Test Zone occupies 52 km2 (20 mi2

) in the northeast quadrant of the Yucca 

Flat weapons test basin. Fifteen atmospheric tests occurred in this area between 1951 and 1958. 

Area 9 was used extensively for underground nuclear testing; 100 such tests occurred from late 1961 

to mid-1992. Of the dozen underground tests involving the simultaneous detonation of multiple 

devices, most involved the use of separate emplacement holes (two or more holes, each with a single 

device). There is one stockpile stewardship emplacement hole in Area 9.

Area 9 Nuclear Test Zone

The Area 9 sanitary landfill is in a subsidence crater formed as the result of a subsurface nuclear 

detonation in the early 1960s. In October 1995, the landfill underwent partial closure as a Class II 

landfill and reopened as a Class III construction and demolition debris landfill. 

2.2.10

This area in the Nuclear Test Zone occupies 54 km2 (21 mi2

) in the northeast quadrant of the Yucca 

Flat weapons test basin. Area 10 was the location for the Nation's first nuclear missile system test, an 

air-to-air rocket detonated in mid-1957. This was the only nuclear rocket test ever conducted at the 

Area 10 Nuclear Test Zone
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NTS. Two of the earliest shallow nuclear cratering experiments at the NTS were detonated in 1951 

and 1955 at this location. Resuming with the deeply buried SEDAN cratering experiment in mid-1962 

and extending through early 1991, a number of underground nuclear tests occurred in Area 10. 

Counting both the cratering and contained underground tests, there were 57 nuclear tests. No 

atmospheric tests were conducted in Area 10. A number of the underground tests were simultaneous 

detonations of multiple devices in the same emplacement hole, while others involved the firing of 

multiple devices with each device in a separate emplacement hole. 

Area 10 is the site of SEDAN Crater, which was formed by a thermonuclear device detonated in July 

1962. It left a large throw-out crater with a diameter of 390 m (1,280 ft) and a depth of 98 m (320 ft). 

SEDAN was the first in a series of 23 PLOWSHARE tests conducted at the NTS to develop peaceful 

uses of nuclear explosives. The SCOOTER Crater, also in Area 10, is the result of a 500-t 

conventional HE experiment in 1960. The area includes underground bunkers and mud pits.

2.2.11

This area, which is divided between the Nuclear Test and Reserved Zones, occupies 67 km2 (26 mi2

) 

along the eastern border of the NTS. Project 56 consisted of four atmospheric plutonium-dispersal 

safety tests in the northern portion of Area 11 in 1955 and 1956 in what is now known as Plutonium 

Valley (see Section 2.3.2 for additional information on safety tests). Because of the radioactive 

residue that remains, DOE used Area 11 for realistic training drills in radiological monitoring and 

sampling operations. Training was discontinued by the current contractor because of concern for 

plutonium intakes. 

Area 11 Nuclear Test and Reserved Zone

Although no full-scale atmospheric tests occurred in Area 11, five underground nuclear weapons tests 

occurred at this location between the Spring of 1966 and early 1971. A 1950s-era experimental jet 

was located in Plutonium Valley and later used by the Accident Response Group for training. 

Contamination was spread throughout the interior. The aircraft was recently removed for 

decontamination and transported to a U.S. Air Force base. 

A number of technical facilities that remain in Area 11 are essentially no longer in use; NNSA/NSO is 

maintaining some of these in varying states of readiness in case there is a future requirement or need 

for such facilities. An explosive ordnance disposal facility in the southern portion of Area 11 functions 

as a RCRA-permitted treatment unit. This site consists of a detonation pit surrounded by an earthen 

pad, approximately 8 m (25 ft) by 31 m (100 ft), and support equipment including a bunker, electrical 

shot box, and electrical wiring.

2.2.12

This area, which is in the Nuclear or HE Test Zone, occupies 104 km2 (40 mi2

) at the northern 

boundary of the NTS on Rainier Mesa. No atmospheric nuclear tests occurred at this location; 

however, Area 12 was the site of the AEC’s first fully contained underground nuclear detonation. The 

RAINIER test took place on September 19, 1957, in a horizontal tunnel mined about 487 m (1,600 ft) 

into the mesa and 274 m (900 ft) beneath its top. 

Area 12 Nuclear or HE Test Zone

In the past several decades, a number of tunnels were mined into Rainier Mesa, in which most of the 

DOD horizontal line-of-sight (LOS) exposure experiments occurred. The N-, P-, and T-tunnel 

complexes, in particular, were developed extensively during the 1970s and 1980s. The tunnel 

experiments usually involved complex construction of large-diameter (up to 9 m [27 ft]) LOS pipes and 

special closure mechanisms, blast and gas seal doors, and stemming plugs. The G-tunnel complex 
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was established for nuclear testing purposes but, since 1971, has been used only as an underground 

research facility. 

Of the 61 underground nuclear tests performed in Area 12 between late 1957 and the fall of 1992, two 

were detonated in vertical stemmed holes, and the 59 others were detonated in mined tunnels. 

Several tests in tunnels resulted in containment failures and the release of radioactive material (see 

Section 2.3.3 for additional information). 

In addition to its use for nuclear testing purposes, N-tunnel was the location of a Nonproliferation 

Experiment involving 1.3 million kg (2.9 million lb) of conventional explosives detonated on September 

22, 1993. Observers from the United Nations Geneva Conference on Disarmament were present. 

The acquired information and data are being used to develop verification requirements to support 

activities in relation to both the Nonproliferation Treaty activities and the Comprehensive Test Ban 

Treaty.

DOD operates an HE research and development tunnel in Area 12. This reusable test bed supports 

programs involving the detonation of conventional or prototype HE and munitions. Because of the 

remote location, the Area 12 camp was constructed in the early 1960’s to support underground testing 

for the Area 12 tunnel complexes. Support structures included a major maintenance building, miner’s 

change house, craft and repair shops, a first aid facility, and a supply depot. Billeting was available 

for underground workers supporting tests. Other facilities in the Area 12 camp included a cafeteria, 

motor pool, and recreation hall. The Area 12 Base Camp was used until the testing period ended in 

1992. 

2.2.13

Officially, there is no Area 13 within the NTS boundary; however, there is a land plot on the NTTR 

Complex, known as NTTR Complex Area 13, which is off the northeast corner of the NTS. This was 

the location for Project 57, a plutonium-dispersal safety experiment in early 1957 (See Section 2.3.2). 

Area 13 Nellis Test and Training Range Complex

2.2.14

This Reserved Zone area occupies 67 km2 (26 mi2

) in the south-central portion of the NTS. Because 

this area is relatively isolated from major NTS operational and support facilities, no atmospheric or 

underground nuclear tests have occurred in Area 14. 

Area 14 Reserved Zone

2.2.15

This Reserved Zone area occupies 96 km2 (37 mi2

) at the northeast corner of the NTS. No 

atmospheric tests occurred at this location, but three underground nuclear tests occurred between 

early 1962 and mid-1966. There were two major complexes in Area 15, the HARDHAT/PILEDRIVER 

site and the U.S. Environmental Protection Agency (EPA) Farm Complex. Ongoing environmental 

remediation activities have taken place at both sites since the mid-1990s. 

Area 15 Reserved Zone

HARDHAT was conducted on 2/15/62 at the U15a shaft and PILEDRIVER was conducted on 6/2/66

at U15a.01 tunnel. The purpose of the HARDHAT/PILEDRIVER tests was to investigate the 

simulated effects of a nuclear surface detonation on a deeply buried, super-hard command-andcontrol center in a granite rock formation. 

From 1978 to 1983, the Spent Fuel Test Complex also known as Climax Mine was a separately mined 

drift at the HARDHAT/PILEDRIVER site. The purpose of this study was to learn more about how 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 21 of 97

granite would react to heat and radiation from spent nuclear fuel. In the test, spent fuel was sealed in 

protective canisters and lowered underground. An underground emplacement vehicle put the 

canisters in lined test holes. All equipment used to handle the canisters was operated by remote 

control. The canisters were stored in the Climax granite stock for 3 yr, then removed and repackaged 

at the Engine Maintenance Assembly and Disassembly (E-MAD) facility in Area 25 before shipment to 

the Idaho National Engineering and Environmental Laboratory.

As part of the DOE long-range safety program, the U.S. Public Health Service (and later the EPA) 

developed and operated an experimental 30-acre dairy farm in Area 15 between 1965 and 1981. 

Researchers studied the passage of airborne radionuclides through the soil-forage-cow’s milk food 

chain. In addition, cows were fed plutonium-loaded capsules to study the metabolic process and 

effects of the material. The facilities included irrigated cropland, an irrigation reservoir, and typical 

structures for a Grade A dairy farm. These facilities were also used for autopsy studies of animals 

that grazed on the NTS.

2.2.16

This area, which is in the Nuclear or HE Test Zone, occupies 73 km2 (28 mi2

) in the west-central 

portion of the NTS. No atmospheric tests have occurred at this location. Area 16 was established in 

1961 for exclusive DOD use in support of a nuclear effects experiment that required a tunnel in an 

isolated area away from other active weapons test areas. From mid-1962 to mid-1971, six 

underground nuclear weapons effects tests occurred in the tunnel complex. Several tests breached

the tunnel containment systems. Radioactive materials include TRU and fission products. Area 16 

Camp was set up in the early 1960’s to house the Area 16 tunnel workers. The facilities were 

residential in nature and included residential (52), dining (2), shower (2), kitchen, and recreation 

trailers. The camp was dismantled sometime between the mid 1960’s and 1972. In the early 1990’s, 

the Defense Threat Reduction Agency (DTRA) began using Area 16 tunnels for HE research and 

development in support of programs involving the detonation of conventional or prototype explosives 

and munitions. 

Area 16 Nuclear or HE Test Zone

2.2.17

This area, which is in the Reserved Zone, occupies 80 km2 (31 mi2

) in the north-central portion of the 

NTS. It has been primarily a buffer between other testing activities. No atmospheric tests or 

experimental activities of programmatic consequence have occurred in Area 17. 

Area 17 Reserved Zone

2.2.18

This area, which is in the Reserved Zone, occupies 231 km2 (89 mi2

) in the northwest quadrant of the 

NTS. The inactive Pahute airstrip is in the east-central portion of the area. Area 18 was the site of 

four nuclear weapons effects tests in early to mid-1962. Two of these tests were atmospheric (slightly 

aboveground) and the other two were cratering experiments. SULKY, a PLOWSHARE test, in late 

1964 was the first nuclear cratering test conducted by the United States after ratification of the Limited 

Test Ban Treaty. DANNY BOY and JOHNNIE BOY resulted in Trinity glass debris. LITTLE FELLER I 

and II resulted in TRU and fission product soil contamination and were very low-yield effects tests. 

The SULKY device was placed fairly deep for its yield and, as a consequence, did not produce a 

crater, although it did produce a mound of broken rock. In addition, in 1964 this area was used for 

Project DUGOUT, a PLOWSHARE-sponsored test using chemical HE to investigate the potential use 

of nuclear explosives for ditch digging in dense hard rock. The resultant crater was 87 m (285 ft) long, 

41 m (135 ft) wide, and 11 m (35 ft) deep.

Area 18 Reserved Zone
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The Pahute CP, now abandoned, is in the northeast corner of the area; it was used until 1971 as the 

diagnostic and microwave communications monitoring center for nuclear test events on Buckboard 

and Pahute Mesas (Areas 18, 19, and 20). The deactivated Pahute airstrip, in the east-central portion 

of Area 18, was used primarily for shipments of supplies and equipment related to Pahute Mesa 

high-yield underground nuclear test operations.

2.2.19

This area in the Nuclear Test Zone occupies 388 km2 (150 mi2

) of the Pahute Mesa in the northwest 

corner of the NTS. Area 19 was developed for high-yield underground nuclear tests, and no 

atmospheric nuclear tests occurred there. The geology of Pahute Mesa makes it possible to test 

devices at much greater depths than in Yucca Flat (down to more than 1,370 m [4,500 ft]). The 

greater depth and isolation allowed much higher yield tests with minimal levels of ground motion felt in 

Las Vegas, more than 160 km (100 mi) away. From the mid-1960s to 1992, 36 underground nuclear 

tests occurred. This area contains underground radioactive material areas because of tests and 

post-test drilling pads. Soil activity is from fission products. There are five stockpile stewardship 

emplacement holes in Area 19. 

Area 19 Nuclear Test Zone

2.2.20

This area in the Nuclear Test Zone occupies 259 km2 (100 mi2

) in the extreme northwest corner of the 

NTS. Area 20, like Area 19, was developed in the mid-1960s as a suitable location for high-yield 

underground nuclear tests; there were no atmospheric nuclear tests there. A total of 49 tests 

occurred. Three underground nuclear tests in the 1 Mt and greater yield range occurred on Pahute 

Mesa between 1966 and 1976. These tests were the well-publicized BOXCAR, BENHAM, and 

HANDLEY tests. From the mid-1960s to 1992, 46 contained underground nuclear tests occurred in 

Area 20. All of these tests consisted of the detonation of a single nuclear device in a drilled

emplacement hole. Area 20 boundaries were expanded after SCHOONER to incorporate an 

extensive fission product plume and throw-out debris.

Area 20 Nuclear Test Zone

One nuclear test detection experiment and three PLOWSHARE tests occurred on Pahute Mesa. The 

PLOWSHARE tests included the nuclear cratering experiments PALANQUIN, CABRIOLET, and 

SCHOONER. PALANQUIN, detonated in the spring of 1965, was the first nuclear test on Pahute 

Mesa. The PALANQUIN and CABRIOLET tests were low yield. TRU and fission products are 

present, as is Trinity glass. There are two stockpile stewardship emplacement holes in Area 20.

2.2.21

There is no Area 21 on the NTS.

Area 21

2.2.22

Area 22, in the southeastern corner, serves as the main entrance to the NTS, with vehicle access 

from Las Vegas by U.S. Highway 95. The area between Highway 95 and the Mercury town site was 

annexed to the NTS in 1964. Area 22 was home for Camp Desert Rock during the early days of 

atmospheric testing. The camp opened in September 1951 as a Sixth Army installation for housing 

troops taking part in military exercises at NTS; at that time, it was primarily a trailer and tent camp with 

several semipermanent structures and an airstrip. During the 1955 test series, the camp housed 

about 9,000 men from the military services, some of whom saw a single test and departed for their 

home duty stations while others stayed through the entire test series. Camp Desert Rock was not 

used by the military after 1958, and many of the structures were moved to other parts of the NTS. 

Area 22 Reserved Zone
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Essentially all of the remaining facilities except the airstrip were dismantled and destroyed as scrap or 

salvaged. The AEC resurfaced and enlarged the Desert Rock airstrip in 1969, extending the runway 

to a length of 2,155 m (7,500 ft). This airstrip served the NTS. At present, the airport provides no 

services, although it is available for emergency landings.

2.2.23

This area, which is in the Reserved Zone, occupies 13 km2 (5 mi2

) in the southeastern portion of the 

NTS and is the location of the Site’s largest operational support complex. Mercury, which was 

established in 1951, is the main administrative and industrial support center. Permanent structures 

and services include housing and cafeteria services, laboratory, maintenance, communication and 

support facilities, computer facilities, warehouses, storage yards, motor pools, and administrative 

offices. Mercury also houses the NNSA and the health physics, medical, and fire departments. 

Mercury is approximately 8 km (5 mi) from U.S. Highway 95. 

Area 23 Reserved Zone

The Area 23 Sanitary Landfill for all NTS organizations is a Class II landfill just west of Mercury. The 

landfill is an open, rectangular pit with nearly vertical sides. Because of its Class II designation, the 

landfill is open to receive all types of nonhazardous solid waste. The current capacity of the landfill is 

approximately 4.5 million m3 (6 million cubic yards). A RCRA-compliant closed hazardous waste site 

is next to the landfill. NNSA/NSO conducts periodic monitoring in accordance with State regulations 

at this location.

2.2.24

Area 24 is the designation for the support area in metropolitan Las Vegas. The North Las Vegas 

Facility (NLVF) includes approximately 80 acres of property and is located on Losee Road in North 

Las Vegas. The NLVF was used for pre-staging and equipment fabrication in support of nuclear 

testing. The complex (Buildings A-1, B-1, B-2, and B-3) contained offices, light laboratories, a large 

machine shop, electrical fabrication shops, chemical etching and plating shops, and a high bay area 

dedicated to the assembly of instrumentation trailers used for tests at the NTS. Edgerton, 

Germeshausen, and Grier Corporation (EG&G) technical services and general management occupied 

the facility along with support groups for LANL and Sandia National Laboratory. These workers 

traveled to the NTS as necessary in support of testing. The Reynolds Electrical and Engineering 

Company (REECo) and NNSA/NVO administrative offices were located in Las Vegas near the Sahara 

Avenue and Interstate 15 interchange. 

Area 24

A radiological source range area for calibrating instruments is located in the basement of NLVF 

Building A-1. The facility began operating in 1963 and is still in operation. The range has the 

following principal sources and associated activities: 

241Am (1.17 E-2 mCi)

133Ba (3.14 E-3 mCi) 

137Cs (5.37 E+1 mCi) 

137Cs (8.33 E-3 mCi) 

252Cf (9.42 E-3 mCi) 

239Pu (1.37 E-6 mCi)

239Pu (1.60 E-3 mCi) 

239Pu (2.60 E-7 mCi) 

90Sr (1.54 E-5 mCi) 

90Sr (1.54 E-5 mCi) 

When Bechtel Nevada won the NTS operations and management contract in 1995, REECo, EG&G, 

and Raytheon Nevada operations were consolidated into a single contract. The Bechtel Nevada 

employees and their subcontractors stationed in Las Vegas were located at the NLVF. NNSA/NVO 

moved to a new building (Nevada Support Facility) constructed in 1996 at the NLVF campus. The 

NLVF Buildings B-1 and B-2 were demolished in 2004. NSTec currently manages and operates the 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 24 of 97

test site and its related facilities for the Nevada Site Office. Attachment C contains additional 

information on NTS contractors. 

2.2.25

Area 25, the largest area on the NTS, occupies about 578 km2 (223 mi2

) in the southwestern corner of 

the Site and includes an entrance gate. Area 25 has its own direct U.S. Highway 95 access 

approximately 3 km (2 mi) north of Amargosa. Other than several small and isolated hills of volcanic 

rock in the west-central portion of Area 25, the interior valley floor encompasses what is commonly 

known as Jackass Flats. Roughly in the center of Area 25, Jackass Flats was selected for a series of 

ground tests of reactors, rocket engines, and stages as part of a program to develop nuclear reactors 

for use in the Nation’s space program.

Area 25 Yucca Mountain Project, Reserved, and Research and Experiment Zones

In the early 1960s, the AEC and the National Aeronautics and Space Administration (NASA) 

negotiated an interagency agreement to establish and manage a test area at the NTS called the 

Nuclear Rocket Development Station (NRDS). It consists of three widely separated reactor test cells 

or stands, two Maintenance, Assembly, and Disassembly (MAD) facility buildings, a CP complex, an 

Administrative Area complex, and a radioactive materials storage area. A standard-gauge railroad 

system connects the test stands and the MAD buildings. The railroad transported nuclear reactors 

and engine systems back and forth from the rocket and engine assembly buildings to the test cells 

and engine test stand. The NRDS operated two shallow-land burial radioactive waste disposal units. 

An equipment decontamination facility was operated near the MAD facility. Attachment B contains 

additional information about the NRDS.

During the late 1970s and early 1980s, the E-MAD building was used for high-level radioactive 

materials handling studies. It contained the world’s largest hot cells, which were used to disassemble, 

examine, and package nuclear reactors. These hot cells are highly contaminated. Thirteen hot spent 

fuel assemblies were brought to E-MAD and encapsulated in stainless-steel canisters with welded lid 

closures. Eleven of the canisters were transported to Area 15 in support of the underground Spent 

Fuel-Climax project. The other two canisters were used in aboveground concrete-shielded storage 

studies and shallow dry-well storage studies. When the studies were completed in 1983, the 

canisters were removed from their temporary storage holes and returned to E-MAD. In 1986, all 13 of 

the spent fuel assemblies were repackaged and shipped to the Idaho National Engineering and 

Environmental Laboratory. Due to the destruction of two nuclear reactors and transport of radioactive 

material, the area was extensively contaminated with enriched uranium, niobium, cobalt, and cesium. 

Legacy contamination areas include several highly radioactive burial areas, such as the Reactor 

Machine Assembly and Disassembly (R-MAD) Trolley Dump and leach fields, which have been 

managed under the DOE environmental remediation program since the mid-1990s. 

The former NRDS Administrative Area complex in Area 25, along with much of the land area to the 

north and west of Lathrop Wells Road, has been rededicated as a Yucca Mountain support site. DOE 

is preparing a License Application for a U.S. Nuclear Regulatory Commission permit to operate and 

close a geologic repository under Yucca Mountain. The mountain is just off the western boundary of 

Area 25 and 160 km (100 mi) northwest of Las Vegas and if approved may contain up to 70,000 

metric tons (77,000 tons) of spent nuclear fuel and high-level radioactive waste. About 90% of the 

waste would be from commercial nuclear power reactors and the rest would be wastes from defense 

nuclear reactors.

The 465-m (1,530-ft) BREN Tower in Area 25 received its name from a 1962 experiment known as 

the Bare Reactor Experiment in Nevada. It was used to determine approximate exposures 

experienced by survivors of the Hiroshima and Nagasaki bombings. An unshielded reactor on an 

outside elevator was raised and lowered to determine changes in dose by distance and shielding 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 25 of 97

measurements on target Japanese-type housing. The BREN Tower is a versatile facility used 

intermittently by a number of organizations for sonic boom research, meteorological studies, and free 

fall or gravity drop tests. The tower was recently used in support of the BRILLIANT PEBBLES 

program, and in studies to develop technology and measurement techniques for advanced infrared 

imaging from space satellites. BRILLIANT PEBBLES was a relatively small, computer-operated, 

rocket-powered, laser-equipped missile designed to detect, track, and intercept ballistic missiles. 

The Rock Valley Study Area, south of Jackass Flats Road on the southern boundary of Area 25, was 

selected in 1960 for studies of radiation on a desert ecosystem. Three study plots were fenced in the 

early 1960s, and in 1964 a 137Cs shielded source was installed on a 50-ft tower in the center of one of 

the plots. The cesium source was removed in the fall of 1982. The other two areas were used as 

control areas. Many research projects have been conducted at the Rock Valley facility in the past 

three decades by a number of government-sponsored scientists as well as students and others 

environmental researchers.

The military uses portions of the Area 25 Reserved Zone for land navigation and training exercises. 

The DOD used portions of Area 25 during the 1980s in conjunction with MX (Peacekeeper) missile 

siting studies and canister ejection certification tests; all of these facilities have been removed. At 

present, Area 25 is used by the U.S. Army’s Ballistic Research Laboratory for depleted uranium 

ballistics testing. Two types of tests, open air and X-tunnel, which include hazard classification and 

system tests, are conducted.

DOE established a Treatability Test Facility in Area 25 several years ago for bench-scale testing of 

physical processes for decontamination of plutonium- and uranium-contaminated soils. At present, 

Area 25 is under consideration as a site for a utility-scale research and demonstration solar power 

project planned for the NTS. As noted in the Final NTS environmental impact statement (DOE 

1996a), depending on the technology or technologies being pursued for application at the NTS, the 

solar power project could affect an area as large as 971 hectares (2,400 acres).

2.2.26

This area, which is in the Reserved Zone, occupies 57 km2 (22 mi2

) in the south-central portion of the 

NTS. The area contains the Horn Silver Mine and a leach field from Building 2201. Radionuclides in 

the soil are a mixture of fission products and uranium. No nuclear explosive tests occurred at this 

location. However, the southern portions of the area were used for nuclear-powered ramjet engine 

tests. Although the tests that began in 1957 were successful, this program was terminated in 1973. 

The residual test facilities include a CP, test bunker, compressor house and air storage facilities, and 

a disassembly building. Attachment B contains information about the PLUTO Program. 

Area 26 Reserved Zone

In recent years, these facilities were used as mock reactor facilities to provide Radiological 

Emergency Response training for civilian and Federal emergency teams. In 1981 the DOD and the 

DOE conducted a joint accident nuclear weapons accident training exercise, Nuclear Weapons 

Accident Exercise (NUWAX)-81, at the PLUTO site. The exercise was designed to put into action a 

planned emergency response to radioactive material scattered in the vicinity of a fictitious town as a 

result of the explosion of nuclear weapons. The NUWAX-81 scenario involved a simulated crash of 

an U.S. Army helicopter transporting nuclear weapons to a storage site. Short-lived radioisotopes 

were distributed via an agricultural sprayer to simulate contamination by weapons-grade Pu. In 1983, 

personnel training for emergency response to nuclear weapons accidents was continued with the 

advent of NUWAX-83. A scenario similar to NUWAX-81 was conducted using short-lived 

radioisotopes to simulate contamination with Pu and Am. 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 26 of 97

2.2.27

This area, which is in the Critical Assembly Zone, occupies 130 km2 (50 mi2

) in the south-central 

portion of the NTS. LANL controls this area, which includes five assembly bays, four storage 

magazines, two combination assembly bay/storage magazines, and three radiography buildings. The 

critical assembly facilities are an alternative to the DAF. Area 27 was used in the past for the Super 

Kukla Reactor Facility. As in Area 26, no nuclear explosive tests occurred in this area.

Area 27 Critical Assembly Zone

In addition, the Joint Actinide Shock Physics Experimental Research (JASPER) Facility is in Area 27, 

which became operational in the mid-1990s. In the post-nuclear testing era, JASPER plays an 

integral role in the certification of the Nation’s nuclear weapons stockpile by providing a method to 

generate and measure data about the properties of materials (radioactive chemical elements) at high 

shock pressures, temperatures, and strain rates. These extreme laboratory conditions approximate 

those experienced in nuclear weapons. Data from the experiments is used to determine material 

equations-of-state and to validate computer models of material response for weapons applications. 

Experiment results are used for code refinement to permit better predictive capability and to ensure 

confidence in the U.S. nuclear stockpile. LLNL maintains the responsibility for overall project 

management, physics definition, engineering, health, and safety.

To achieve the high shock pressures, temperatures, and strain rates similar to that of a nuclear 

weapon, JASPER experiments use a two-stage gas gun. A gas gun propels a projectile into a target 

at extremely high velocities, often exceeding 8 kps. The JASPER gas gun is specifically designed to 

conduct research on plutonium and other surrogate materials as targets. The two-stage gun consists 

of a first-stage breech containing gunpowder and a pump tube filled with hydrogen gas and a 

second-stage evacuated barrel for guiding the high-velocity projectile to a radioactive material target. 

Hot gases from the burning propellant drive a heavy piston down the pump tube, compressing the 

gas. At sufficiently high pressures, the gas eventually breaks a rupture valve and enters the narrow 

barrel and propels the projectile, housed in the barrel, toward the target.

When the projectile hits the target, it produces a high-pressure shock wave. In a fraction of a 

microsecond, the shock wave reverberates through the target. Diagnostic equipment triggered by the 

initial wave measures the properties of the shocked material inside the target during this extremely 

brief period. The target is disintegrated by the impact of the projectile and contained within the 

primary confinement chamber. A second confinement chamber protects workers as a safety 

precaution in the unlikely event that the primary system fails. 

2.2.28

Area 28 is no longer in existence. The Area 28 designation applied to a portion of the NTS that has 

been absorbed into Areas 25 and 27. 

Area 28 

2.2.29

This area, which is in the Reserved Zone, occupies 161 km2 (62 mi2

) on the west-central border of the 

NTS. A communications repeater station for the NTS is in the Shoshone Mountains. Area 29 

consists of rugged terrain that includes Mid-Valley, Fortymile Canyon, and Shoshone Mountain. 

Because of its mountainous terrain and relative inaccessibility, limited use has been made of this 

area. Area 29 has served as a buffer zone between activities in Area 25 and weapons-testing 

activities elsewhere on the NTS.

Area 29 Reserved Zone
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 27 of 97

2.2.30

This area in the Reserved Zone occupies 150 km2 (58 mi2

) on the western edge of the NTS. Area 30 

has rugged terrain and includes the northern reaches of Fortymile Canyon. In the past, Area 30 had 

limited use in support of nuclear testing programs. In the spring of 1968, it was the site of Project 

BUGGY, the first nuclear row-charge experiment in the PLOWSHARE Program. BUGGY was 

designed to develop nuclear excavation technology for digging canals or mountain passes. Five small 

devices were spaced 46 m (150 ft) apart at a depth of 41 m (135 ft) and detonated simultaneously in 

early 1968. The result was a trench 255 m (835 ft) long, 77 m (254 ft) wide, and 206 m (675 ft) deep. 

The BUGGY test resulted in large quantities of vitrified glass. This site has limited access. 

Area 30 Reserved Zone

2.2.31

The NTTR Complex includes the NTTR and the TTR. The more-than-12,000-km2 (4,700-mi2

) Range 

buffers the NTS on its north, east, and west boundaries. The TTR, which covers about 1,600 km2

(620 mi2), is approximately 40 km (25 mi) southeast of Tonopah in Nye County, and is inside the 

NTTR boundaries. Further information about the TTR is found in the Sandia National Laboratory site 

profile (ORAUT 2007). According to DOE (2000a), plutonium dispersal tests were conducted at 

NTTR/TTR in 1957 (Project 57) and 1963 (DOUBLE TRACKS and CLEAN SLATE I to III). See 

Section 2.3.2 for additional information. In addition to these events, nuclear tests occurred on the 

NTS in which atmospheric plumes caused contamination to spread beyond the Site boundary to the 

NTTR Complex. The plume of SCHOONER in 1968 appeared prominently on the 1994 aerial 

radiation survey (EG&G 1994). 

Nellis Test and Training Range

2.3 SITE OPERATIONS AND PROCESSES 

This section briefly describes the operations and historic nuclear weapons tests that could have 

resulted in occupational radiation exposure to employees on the NTS site.

Timeline

The sources of radionuclides on the NTS include current and past activities. The Site was the primary 

location for the testing of nuclear explosives in the continental United States between 1951 and 1992. 

Historic testing above or at ground surface included (1) atmospheric testing in the 1950s and 1960s, 

(2) earth-cratering experiments, and (3) open-air nuclear reactor and rocket testing. Since 1961, 

testing of nuclear explosive devices has occurred mainly in vertical drill holes or in mined tunnels until 

the end of the testing era in September of 1992. Environmental restoration at the NTS is ongoing 

through the partnership with the State of Nevada. Status information on remediation projects is 

available in the Federal Facility Agreement and Consent Order documentation (DOE 2004).

The United States entered a unilateral testing moratorium on October 1, 1958, and resumed testing 

on September 15, 1961. Before the moratorium, most tests occurred in the atmosphere. Following 

the resumption of testing in 1962, more than 800 nuclear weapons tests occurred with only one 

identified as an atmospheric test (Small Boy) detonated approximately 10 feet above the ground. No 

tests have occurred since September 23, 1992. Radiological Effluents Released from U.S. 

Continental Tests 1961 Through 1992 (DOE 1996b) provides information on radiological releases that 

resulted from each test. Table 2-1 summarizes the types of tests by the testing era. Table 2-2 

provides a listing of radionuclides of concern for various NTS operations. Table 2-3 presents a listing 

of radionuclides typically deposited following atmospheric tests for various time intervals (10 d, 1 yr, 

20 yr, and 50 yr); the data are calculated gamma radiation exposure rates from fallout and related 

radionuclides from the BUSTER-JANGLE test in 1951. The 233U, 235U, 238U, and 239,240Pu data were
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 28 of 97

omitted primarily to keep the output unclassified. In addition, the background plutonium in Nevada 

and Utah soils comes from worldwide fallout (DNA 1982a).

Table 2-1. Nuclear weapons test timeline.

a

Testing era Number of tests Type of tests

Post-World War II to 1951b 5 Atmospheric 

1951-1958 Atmospheric Testing Period 97 Atmospheric 

2 Cratering (near-surface) 

20 Underground

1958-1961 Voluntary Moratorium

1961-1992 Underground Testing Period 6c Surface 

1 Tower (atmospheric)

7d Cratering (near-surface) 

799e Underground (vertical 

shafts or tunnels)

a. Source: DOE (2000a); 1963 Limited Test Ban Treaty on atmospheric testing; 1992 U.S. cessation of 

nuclear weapon testing. 

b. Excludes TRINITY, July 5, 1945. First nuclear test conducted near Alamogordo, New Mexico, that 

produced a yield of 21 kt. 

c. LITTLE FELLER II, LITTLE FELLER I, CLEAN SLATE I, DOUBLE TRACKS, CLEAN SLATE II, 

CLEAN SLATE III. 

d. Five of the 7 cratering tests were for peaceful purposes as part of the PLOWSHARE Program 

(1960-1968); DANNY BOY, SEDAN, JOHNNIE BOY, PALANQUIN, CABRIOLET, BUGGY, 

SCHOONER. 

e. Total of underground tests at NTS from 1951 to 1992 was 828. 

The following categories summarize NTS operations that could have resulted in radiological releases:

• Atmospheric Weapons Testing

• Safety Tests

• Underground Tests

• Nuclear Reactor Development Tests

• RWMSs

• Laboratories

• Well Logging

• Treatability Test Facility

• Decontamination Facility

• Radiation Instrument Calibration Facilities

• Radioactive Source Storage Areas

• Nuclear Explosives Assembly and Device Assembly Facility

Unless otherwise noted, most of the information in the following sections about the NTS testing 

program, site operations, and facilities is from Final Environmental Impact Statement for the Nevada 

Test Site and Off-Site Locations in the State of Nevada (DOE 1996a).

2.3.1

U.S. aboveground nuclear weapons tests at the NTS began on January 27, 1951, with the detonation 

of a 1-kt air-dropped weapon over Frenchman Flat and ended with the last tower and surface 

weapons effects tests in July of 1962. Little Feller I was the last atmospheric test conducted on 

7/17/62 at the Nevada Test Site (Area 18) and had a “low” yield (i.e., less than 20 kt). More than 100 

atmospheric tests occurred before the signing of the Limited Test Ban Treaty in August 1963. In 

addition to airdrops, atmospheric testing included detonations from towers at heights from 30 to 213 m 

Atmospheric Weapons Testing
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 29 of 97

Table 2-2. Radionuclides of concern for various NTS activities.

a,b

Radionuclide 

of concern

▼

Atmospheric 

Weapons 

Test Areas

Safety 

Test 

Areas

Drill-back 

Operations

Routine 

Tunnel 

Operations

Reentry 

and 

Mineback 

Operations

Nuclear 

Rocket 

Development

LowLevel 

Waste 

Site

LowLevel 

Waste 

Site

Radiochemistry 

and Counting 

Laboratories

Radiograph

Operations

Well 

Logging 

Operations

Treatability 

Test 

Facility

Decontamination 

Facility

Radiation 

Instrument 

Calibration

Radioactive 

Source 

Storage

Nuclear 

Explosive

/Device 

Assembly

NTS Area ►

All areas 

except 

22, 23 & 27

Areas 

5 & 11

Areas

1-10 &

18-20

Areas 1, 

12, 15 & 

16

Areas 1, 

12, 15 & 

16

Areas 

25 & 26

Area 

3

Area 

5

Areas 

6 & 23

Area 

23

Areas

1-10 &

18-20

Area 

25

Area 

6

Areas 

6 & 23

Areas 6 

& 23

Areas 

6 & 27

Period of 

operation ►

1951- 

1963

1956- 

1957

1963- 

1992

1957- 

1992

1957- 

1992

1959- 

1973

Mid 

1960spresent1961- 

present

1958- 

present

1951- 

present

1963- 

1992 1990s

1971- 

2001

1951- 

present

1951- 

present

1951- 

present

Ac-227 E,I E,I P P

Al-28n E E E

Am-241 E,I I E,I E,I E,I E,I E,I P E,I E,I P

Am-243 E,I E,I E,I P 241AmBe E E P

Ba-133 E,I P P E,I E P E,I

Ba-140 P P P P E,I E,I P P P

Cd-109 I I

Ce-139 P Ei,Ii I

i P E,I Ii

Ce-141 P Eg,Ig I

g P E,I E,I P Ec

,Ig

Ce-143 P Ed,Id I

d P P Id

Ce-144 P Ec,Ic I

c P E,I E,I E,I E Ec

,Ic

Cf-252 E E E

Cl-38 n E E E

Cm-244 E,I

Co-57 E,I E,I Ec E,I

Co-60 E,I P E,I E,I E,I E,I E,I E,I E,I E E E,I E,I

Cs-134 E,I P P P P E,I E,I P E P

Cs-137 E,I Ej,Ij E E,Ij E,I E,I E,I E,I I E,I E Ek,Ij E,I E,I

Eu-152 E,I E,I E,I E,I E E,I

Eu-154 E,I P E,I P E E,I

Eu-155 E,I P E,I P E P

Fe-59 Ec

H-3 P I I I I I I P I

Hg-203 E,I

I-131 Ef,If E,If P P P I

f

I-133 Ed,Id E,Id P P I

d

I-135 Ed,Id I

d P P Id

Ir-192 E,I E,I E,I

Kr-85 E

Lu-174 E,I E

Mn-54 E E,I E,I P Ec E,I

Mn-56 El El El El El

Mo-99 Ed,Id I

d P E,I P Id

Na-22 E,I E,I

Na-24 E,I

Nb-95 (See 

Zr-95/ Nb-95)

Ni-63 E,I

Np-237 E,I

Np-239 El El El El El

Pm-147 Ei,Ii I

i E Ec

,Ii

Pu-238 E,I I E,I E,I I E,I P I I El,I

Pu-239 E,I I E,I E,I E,I E,I P I E,I El,I

Pu-240 E,I I E,I E,I E,I P E El,I

Pu-241 E,I E,I P El,I
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 30 of 97

Radionuclide 

of concern

▼

Atmospheric 

Weapons 

Test Areas

Safety 

Test 

Areas

Drill-back 

Operations

Routine 

Tunnel 

Operations

Reentry 

and 

Mineback 

Operations

Nuclear 

Rocket 

Development

LowLevel 

Waste 

Site

LowLevel 

Waste 

Site

Radiochemistry 

and Counting 

Laboratories

Radiograph

Operations

Well 

Logging 

Operations

Treatability 

Test 

Facility

Decontamination 

Facility

Radiation 

Instrument 

Calibration

Radioactive 

Source 

Storage

Nuclear 

Explosive

/Device 

Assembly

NTS Area ►

All areas 

except 

22, 23 & 27

Areas 

5 & 11

Areas

1-10 &

18-20

Areas 1, 

12, 15 & 

16

Areas 1, 

12, 15 & 

16

Areas 

25 & 26

Area 

3

Area 

5

Areas 

6 & 23

Area 

23

Areas

1-10 &

18-20

Area 

25

Area 

6

Areas 

6 & 23

Areas 6 

& 23

Areas 

6 & 27

Period of 

operation ►

1951- 

1963

1956- 

1957

1963- 

1992

1957- 

1992

1957- 

1992

1959- 

1973

Mid 

1960spresent1961- 

present

1958- 

present

1951- 

present

1963- 

1992 1990s

1971- 

2001

1951- 

present

1951- 

present

1951- 

present

Pu-242 I E,I E,I P 238PuBe El

,I E E

Ra-226 E,I E,I E,I E,I 226RaBe El

,I P P

Rh-100 Em

Rh-101 Em,Im Em

Rh-102m Em,Im Em

Rh-106 P P E P P 

Ru-103 P Ee,Ie E,Ie P E,I E,I P Ec,Ie

Ru-106 P Ec,Ic E,Ic P E,I E,I P Ec,Ic

Sb-124 P E,I E,I P Ec

Sb-125 E,I P E,I P E E

Sc-46 El El El El El

Sn-113 I

Sr-85 E,I E,I E,I

Sr-89 P Ee,Ie P El,Ie P El,Ie

Sr-90/Y-90 E,I Eh,Ih E,Ih E,Ih E,I E,I I E,I E E,Ih E,I E,I

Ta-182 E E,I

Tc-99m P P P P P P

Te-132 Ef,If I

f P P If

Th-228 E,I E,I El,I E,I E,I

Th-230 E,I E,I E,I

Th-232 E,I E,I

U-233 E,I E,I

U-234 I E,I E,I El,I

U-235 I E,I E,I E,I El,I

U-238 I E,I E,I

Xe-133 E P 

Xe-133m E P

Xe-135 E P

Y-88 E,I

Y-90 (See 

Sr-90/Y-90)
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 31 of 97

Radionuclide 

of concern

▼

Atmospheric 

Weapons 

Test Areas

Safety 

Test 

Areas

Drill-back 

Operations

Routine 

Tunnel 

Operations

Reentry 

and 

Mineback 

Operations

Nuclear 

Rocket 

Development

LowLevel 

Waste 

Site

LowLevel 

Waste 

Site

Radiochemistry 

and Counting 

Laboratories

Radiograph 

Operations

Well 

Logging 

Operations

Treatability 

Test 

Facility

Decontamination 

Facility

Radiation 

Instrument 

Calibration

Radioactive 

Source 

Storage

Nuclear 

Explosive

/Device 

Assembly

NTS Area ►

All areas 

except 

22, 23 & 27

Areas 

5 & 11

Areas

1-10 &

18-20

Areas 1, 

12, 15 & 

16

Areas 1, 

12, 15 & 

16

Areas 

25 & 26

Area 

3

Area 

5

Areas 

6 & 23

Area 

23

Areas

1-10 &

18-20

Area 

25

Area 

6

Areas 

6 & 23

Areas 6 

& 23

Areas 

6 & 27

Period of 

operation ►

1951- 

1963

1956- 

1957

1963- 

1992

1957- 

1992

1957- 

1992

1959- 

1973

Mid 

1960spresent

1961- 

present

1958- 

present

1951- 

present

1963- 

1992 1990s

1971- 

2001

1951- 

present

1951- 

present

1951- 

present

Y-91 Ee,Ie I

e Ie

Yb-169 E,I 

Zr-95/Nb-95 P Ec,Ic E,Ic P E,I E,I P E Ec,Ic

Zr-97 Ed,Id I

d P P Id

a. Sources: REECo (1993, 1995).

b. E = External hazard per REECo (1995); I = Internal hazard per REECo (1993); P = Possible based on process knowledge and health physics expertise (this designation means the radionuclide was not 

specifically listed for this facility or process in REECo (1993) or (1995), but should still be considered as a possibility).

c. 1, 10, 100, and 365 d post-test (within first year).

d. 1 d post-test.

e. 10 and 100 d post-test.

f. 1 and 10 d post-test.

g. 10 d post-test.

h. 100, 365, and 10,000 d post-test.

i. 365 d post-test.

j. 10,000 d post-test.

k. After first year only.

l. External was added to this table, but was not included in REECo 1995 for this facility/process.

m. The fission yields for these radionuclides are low and are not considered to have much radiological significance compared to the other radionuclides listed.

n. Activation product important for external gamma dose for armed forces personnel (NAS 1989) added in response to the NTS Site Profile Evaluation (S. Cohen & Associates, 2005). Due to the short half 

life, this radionuclide would not be a dose factor for reentry personnel.
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 32 of 97

Table 2-3. Radionuclides typically deposited after atmospheric tests for 

various time intervals.

a

Radionuclide Period

mCi/m2 10 d 1 yr 10 yr 20 yr 50 yr

Be-7 2.61E-07 3.46E-07 7.96E-28

Na-24 1.02E-06

Mn-54 1.96E-05 1.05E-05 5.69E-09 1.34E-12 1.75E-23

Fe-55 3.57E-05

Fe-59 2.56E-05 1.89E-06 1.95E-28

Co-57 3.56E-05 1.62E-05 3.62E-09 3.16E-13

Co-58 7.68E-02 2.55E-03 3.40E-17 1.30E-32

Co-60 1.51E-04 1.71E-04 5.20E-05 1.39E-05 2.67E-07

Cu-64 5.29E-06

Cu-67 7.09E-06

W-181

W-185 1.64E-08 1.09E-21

W-187

W-188

Au-198

Au-199

Pb-203

U-237 6.5E-02

U-240 5.47E-06

Np-237

Np-239 1.54E+00

Np-240m 5.52E-06

Am-241 7.05E-09 1.11E-06 1.13E-06 1.13E-06 1.11E-06

Cm-242 1.75E-07 3.00E-06 2.55E-12 7.43E-17 6.83E-17

Ge-77 4.45E-09

As-77 1.50E-04

Se-77m 4.50E-07

As-78

Br-82 3.33E-06

Br-83 7.74E-30

Kr-83m 3.40E-29

Kr-85m 3.18E-16

Kr-85 9.24E-05 5.37E-05 3.01E-05 1.59E-05 2.32E-06

Kr-87

Kr-88 4.99E-25

Rb-88 5.56E-25

Sr-89 7.87E-02 4.28E-04 4.01E-23 2.91E-44

Sr-90 6.10E-04 3.57E-04 2.87E-04 2.24E-04 1.07E-04

Y-90 5.67E-04 3.57E-04 2.87E-04 2.24E-04 1.07E-04

Sr-91 5.40E-07

Y-91m 3.50E-07

Y-91 9.84E-02 9.89E-04 1.48E-20 2.98E-39*

Sr-92 1.30E-25

Y-92 6.70E-19

Y-93 1.45E-06

Zr-95 1.13E-01 2.31E-03 1.39E-18 1.70E-35

Nb-95m 1.97E-03 4.89E-05 2.95E-20 3.61E-37

Nb-95 2.11E-02

Zr-97 6.14E-01
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 33 of 97

Radionuclide Period

mCi/m2 10 d 1 yr 10 yr 20 yr 50 yr

Nb-97m 5.89E-04

Nb-97 6.19E-04 4.97E-03 3.01E-18 3.69E-35

Mo-99 2.55E-01

Tc-99m 2.43E-01

Ru-103 1.28/E-01 4.51E-04 4.69E-29

Rh-103m 1.28E-01 4.52E-04 4.69E-29

Ru-105 1.03E15

Ru-105m 1.03E-15

Rh-105m 2.63E-02

Ru-106 7.73E-03 1.01E-02 2.04E-05 2.06E-08 2.12E-17

Rh-106 7.73E-03 1.01E-02 2.04E-05 2.06E-08 2.12E-17

Pd-109 2.39E-06

Ag-109m 2.40E-06

Pd-111m 5.45E-14

Pd-111 4.40E-14

Ag-111m 5.76E-14

Ag-111 9.54E-03

Pd-112 5.15E-05

Ag-112 6.10E-05

Ag-113 7.23E-15

Cd-115m 8.97E-05

Cd-115 1.27E-03

In-115m 1.38E-03

Cd-117 5.40E-31

In-117m 2.76E-30

In-117 1.86E-30

Sn-121 1.39E-04

Sn-123 3.34E-04 9.79E-05 1.19E-12 1.91E-21 7.91E-48

Sn-125 4.57E-03

Sb-125 1.04E-04 2.48E-04 2.46E-05 1.89E-06 8.56E-10

Sb-126 1.02E-03

Sn-127 9.86E-35

Sb-127 2.40E-02

Te-125m 1.01E-04 1.02E-05 7.81E-07 3.54E-10

Te-127m 8.98E-04 1.68E-04 1.40E-13 1.15E-23 6.43E-54

Te-127 2.17E-02 1.66E-04 1.39E-13 1.14e-23 6.37E-54

Sb-128 7.23E-09

Sb-129 1.56E-16

Te-129m 6.84E-03

Te-129 4.37E-03

I-130 2.91E-08

Te-130m 1.85E-03

Te-131 3.37e-04

I-131 2.80E-01

Xe-131m 1.47E-03

Te-132 2.38E-01

I-132 2.45E-01

I-133 3.84E-03

Xe-133m 7.41E-03

Xe-133 5.71E-01

I-135 4.7E-10
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 34 of 97

Radionuclide Period

mCi/m2 10 d 1 yr 10 yr 20 yr 50 yr

Xe-135m 1.47E-10

Xe-135 1.10E-06

Cs-136 3.15E-03

Cs-137 7.76E-04 8.99E-04 7.30E-04 5.77E-04 2.90E-04

Ba-137m 7.24E-04 8.43E-04 6.84E-04 5.41E-04 2.71E-04

Ba-139

Ba-140 3.65E-01

La-140 4.09E-01

La-141 1.50E-17

Ce-141 2.04E-01 9.67E-06 2.82E-35

La-142

Ce-143 3.39E-02

Pr-143 3.49E-01

Ce-144 2.15E-02 7.87E-03 2.59E-06 3.48E-10 8.51E-22

Pr-144 2.15E-02 7.87E-03 2.59E-06 3.48E-10 8.51E-22

Pr-145 1.69E-11

Nd-147 1.45E-01

Pm-147 1.45E-03 2.60E-03 2.41E-04 1.71E-05 6.12E-09

Nd-149 1.60E-39

Pm-149 3.36E-02

Pm-150 4.41E-28

Pm-151 3.03E-03

Sm-153 1.02E-02

Sm-156 1.10E-08

Eu-155 6.33E-04 5.49E-04 1.48E-04 3.46e-05 4.38E-07

Eu-156 9.98E-03

Eu-157 5.19E-06

Gd-159 9.39E-06

Tb-161 7.18E-04

a. Source: DNA (1982b).

(100 to 700 ft), detonations on the surface of the ground, and the use of helium-filled balloons 137 to 

457 m (450 to 1,500 ft) above the ground to loft weapons. 

Depending on the proximity of the explosion to the ground surface and the size of the yield, surface 

disturbances from atmospheric testing varied widely. The greatest surface disturbances typically 

occurred when an air-dropped weapon penetrated the ground surface to a shallow depth (about 15 m 

[50 ft]) before detonation. Such a test with a yield of 100 kt would result in a crater about 36 m (120 ft) 

deep and about 219 m (720 ft) in diameter (DOE 1996a).

Radioactivity from atmospheric tests was dispersed by three primary mechanisms: throwout, base 

surge, and fallout. Throwout occurred at detonation when the fireball propelled large volumes of rock 

and soil upward. Base surge was the settling and outward movement of the throwout. Fallout is the 

portion of material that did not settle, but rose and merged with weapon residues. These materials 

descended to the ground over the next few hours or more. The extent and distribution of 

contamination from an atmospheric test was quite variable depending on the height of detonation, the 

yield and type of device, the nature of the ground surface, the mass of inert material surrounding the 

device, and weather conditions at the time of and following the test. Typical radionuclides formed 

during atmospheric testing included isotopes of strontium, cesium, barium, tritium, and iodine. Of 

these, 90Sr and 137Cs are of concern because of their longer half-lives of 28 and 29 yr, respectively 

(DOE 1996a)
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The vast majority of radioactivity released during atmospheric testing decayed quickly after each test. 

For example, for a 1-kt atmospheric test, the initial release after 1 min was about 4.1 x 1010 Ci. This 

activity reduced to 1 x 107 Ci just 12 hr after the detonation. If the activity remaining after 12 hr was 

used as the basis for estimates of total release, about 6 x 1010 Ci were released during atmospheric 

testing between 1951 and 1963 at the NTS (DOE 1996a).

Many of the fission products released during detonations were dispersed into the atmosphere, and 

much of the residual radioactivity has decayed in the 40 yr since the last atmospheric test. 

Nonetheless, some of the longer-lived radionuclides remain in the soil and physical structures. The 

primary radionuclides that remain on the NTS from historic atmospheric testing include americium, 

plutonium, cobalt, cesium, strontium, and europium. 

Residual contamination for atmospheric testing is present in Areas 1, 2, 3, 4, 7, 8, 9, and 10 of the 

NTS and on Buckboard Mesa in Area 18. All areas except Areas 22, 23, and 27 have some 

monitoring and restrictions as a result of these tests. The routine device for external exposure 

monitoring in the atmospheric test areas is the whole-body thermoluminescent dosimeter (TLD) 

(REECo 1995). Table 2-4 summarizes the major sources of radioactivity on the NTS.

2.3.2

Safety tests evaluated the safety of nuclear weapons in accident scenarios. Safety experiments that 

produced no nuclear explosions but created surface contamination were conducted at locations on 

the NTTR (Area 13) and TTR (DOUBLE TRACKS and CLEAN SLATE I-III), at Plutonium Valley in 

Area 11, and at the GMX site in Area 5. Contamination from these sites is limited to surface soils. 

The depth of contamination could vary among sites, but it is not expected to exceed 1 ft at any site 

(NDEP 2000). 

Safety Tests and Contaminated Surface Soils

The GMX PROJECT site in NTS Area 4 was used for 24 specific equation-of-state studies or 

experiments with fissile materials from 1954 to 1956. The purpose of these early GMX experiments 

was to determine if a nuclear chain reaction could occur after the accidental triggering of conventional 

HE materials in an assembled weapon. 

PROJECT 56 consisted of four discrete surface plutonium dispersal safety tests in 1955 and 1956 in 

NTS Area 11. The purpose of these safety experiments was to determine whether a weapon 

damaged in an accident would detonate with a nuclear yield, even if some or all of the HE component 

burned or detonated. One of these safety tests went partially critical, creating some fission products 

that contribute to the surface contamination. An enriched uranium safety test cross-contaminated with 

plutonium took place in Area 11a. Experiments 11b, c, and d were ground-zero detonations. A small 

underground waste dump is inside the contaminated area boundary. Large metal debris resulted in a 

Radiation Area near 11c. Area 11 of the NTS is known as Plutonium Valley because of the 

contaminated soil from the safety experiments and has been used for realistic drills in radiological 

monitoring and sampling operations.

The PROJECT 57 test area, also known as NTTR Area 13, was a 10- by 16-mi block of land abutting 

the northeast boundary of the NTS. On April 24, 1957, the safety experiment commenced when the 

HE charge of a nuclear weapon’s warhead destroyed the weapon with no atomic explosion. A 

radiological survey team entered the experiment area and confirmed there was no beta or gamma 

radiation hazard from a partial nuclear yield. All personnel entering the area were required to wear full 

protective suits and respirators to protect from the alpha radiation hazard. The extent and distribution 

of plutonium contamination was mapped and the area was fenced and posted. Contaminated 

equipment was disposed in waste burial sites inside Area 13. The PROJECT 57 site lay abandoned 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 36 of 97

Table 2-4. Residual radioactivity on the NTS, January 1996.

a

Source of radioactivity Type of area

Environmental 

media

Major known 

elements or waste Depth range

Approximate activity 

(curies)

Atmospheric testsb Aboveground nuclear 

proving area

Surface soils and 

test structures

Americium

Cesium 

Cobalt 

Plutonium 

Europium 

Strontium

At surface 20 

Safety testsb Aboveground 

experimental areas

Surface soils Americium

Cesium 

Cobalt 

Plutonium 

Strontium

Less than 0.9 m (3 ft) 35 

Big Explosives Experimental 

Facilityb 

Bunkers Underground Depleted uranium N/A N/A

Deep underground testsb Underground nuclear 

testing areas

Soils, alluvium, and 

consolidated rock

Tritium

Fission and activation 

products

Typically less than 

640 m (2,100 ft); but 

may be deeper

Greater than 300 million

Nuclear reactor testsb Nuclear rocket motor, 

reactor, and furnace 

testing area

Surface soils Cesium

Strontium 

Less then 3 m (10 ft) 1

Shallow borehole testsb Underground nuclear 

testing area

Soils and alluvium Americium

Cesium 

Cobalt 

Europium 

Plutonium 

Strontium

Less than 61 m (200 

ft)

2,000 at land surface; 

depth unknown

Shallow land burial of low-level 

wasteb 

Waste disposal landfills Soils and alluvium Dry-packaged 

low-level and 

mixed-wastes

Less than 9 m (30 ft) 500,000 at time of disposal; 

no decay

Crater disposalb Subsidence crater with 

sidewalls, cover, and 

drainage

Soils and alluvium Bulk contaminated 

soils and 

equipment

Less than 30 m (100 

ft)

1,250 at time of disposal; 

no decay

Greater containment disposalb Monitored underground 

waste disposal borehole

Soils and alluvium Tritium

Americium

Less than 30 m (100 

ft)

9.3 million at time of 

disposal; no decay

U1a Complexb Mined underground 

complex 

Underground (Special Nuclear 

Material (SNM) 

Tritium

Depleted uranium

To 350 m (1,000 ft) N/A

Containment pondsc Surface Water, air, and soil Tritium N/A 130

Laboratoriesc Surface Air and soil Tritium At surface 500 μCi

Joint actinide research (JASPER)c Surface Air and soil SNM

Actinides

N/A N/A

Contaminated surface soilsc Surface Soil Americium

Plutonium

0 to 5 cm Assumed to be included in 

above totals

a. N/A = not available. 

b. DOE (1996a). 

c. DOE (1997a). 
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for nearly 20 yr until 1981 when DOE sought funding for the decontamination and decommissioning of 

Area 13. Hundreds of thousands of cubic yards of soil were removed from Area 13 during the 

decontamination efforts and disposed at NTS. 

Operation Roller Coaster was an experimental series of plutonium dispersal tests that were conducted 

in 1963 at the TTR. The purpose of these tests was to evaluate storage and transportation issues. 

The DOUBLE TRACKS site was remediated in 1995 and 1996 and the CLEAN SLATE I corrective 

actions were performed in 1997. Contaminated soil was transported to the NTS Area 3 RWMS. 

Corrective actions for CLEAN SLATE II and III are pending an agreement between the State of 

Nevada and the Federal government on the level of cleanup. A summary of the plutonium dispersal 

tests is listed below: 

• GMX conducted at NTS Area 5, 1954-1956

• PROJECT 56 conducted at NTS Area 11 (Plutonium Valley), 1955 1956

• PROJECT 57 conducted at NTTR Area 13 in 1957

• DOUBLE TRACKS and CLEAN SLATE I-III (Operation Roller Coaster) conducted at TTR in 

1963

The safety tests used mixtures of plutonium and uranium dispersed by conventional explosives. 

Concurrent with and after these detonations, extensive studies were conducted to understand the 

dispersal and transport of these radionuclides in the environment including uptake by plants and 

animals. These studies were documented in a benchmark series of papers by the Nevada Applied 

Ecology Group, a panel of scientists chartered to investigate the effects of testing at the NTS. The 

immediate effects of the tests included the dispersal of plutonium and uranium over wide areas. To 

determine the area affected by these tests, inventories were conducted and later augmented by 

extensive sampling efforts in the field under the Radionuclide Inventory and Distribution Program. 

These studies resulted in the definition of affected areas. The GMX PROJECT at Area 5 resulted in 

the contamination of about 240 acres, and the PROJECT 56 tests resulted in the contamination of 

about 2,200 acres. On the NTTR Complex, two disturbed areas total slightly less than 1,000 acres. 

On the TTR, almost 670 acres were contaminated. 

At both onsite and offsite locations, the primary radionuclides are plutonium, uranium, and americium, 

with lesser amounts of cesium, strontium, and europium. These long-lived radionuclides remain in the 

surface soils in the vicinity of the test areas and are available for transport by wind and uptake by 

plants and animals. Extensive research into the mobility of the radionuclides has found that wind can 

transport such contaminants and concentrate them in mounds around desert shrubs, and water can 

cause plutonium to migrate deeper into the soils with time. At present, the radionuclides are relatively 

immobile unless the soils are disturbed. Evidence of wind-driven contamination is low. The heat of 

initial blast, soil bonding and weathering, and the rockiness of native soil prevent deep migration 

(REECo 1995). DOE (1997b) provides an estimate of the 239+240Pu inventory at the studied sites.

Surface soils in certain areas on and off the NTS were contaminated with one or more of plutonium, 

americium, and tritium from nuclear device safety, atmospheric, or cratering tests. Vehicular activity is 

forbidden in these areas. There is no evidence of significant wind dispersal after initial deposition. 

Rain and runoff have caused migration in some areas. These areas could become sources of 

exposures to americium and plutonium if the contaminated soils were to be resuspended during windy 

conditions, surface cleanup, construction, vehicular travel, or similar activities. 
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Areas 1 to 12 and 15 to 20 on the NTS, Area 13 on NTTR, and the CLEAN SLATE I to III sites on the 

NTTR at the TTR contain diffuse sources of radionuclide effluents. Due to occasional high winds, 

some contaminated soil becomes airborne. Results from air samples in these areas indicate the 

routine detection of 241Am and 239+240Pu, but only in concentrations slightly above the minimum 

detectable concentration. The other predominant isotopes found in NTS soil samples are 137Cs and 

238Pu. 

MacArthur (1991) contains inventories of americium and plutonium in contaminated surface soils. 

These areas could become sources of exposure to americium and plutonium if the contaminated soils 

become resuspended.

2.3.3

Since 1963, the United States has conducted all of its nuclear weapons tests underground in 

accordance with the terms of the Limited Test Ban Treaty. Therefore, complete containment of all 

nuclear weapons tests was a dominant consideration in nuclear test operations. 

Underground Tests

Various methods were used for emplacing nuclear test devices so the ensuing explosion was 

contained. The most common method was to place a test device at the bottom of a vertically drilled 

hole. Another method was to place a test device in a tunnel mined horizontally to a location 

sufficiently deep to provide containment. 

The following paragraphs describe processes associated with nuclear weapons tests in vertical drill 

holes and mined tunnels. The information is from DOE (1996a).

2.3.3.1

There were two types of tests in vertical drill holes: Smaller yield devices in relatively shallow holes in 

the Yucca Flat area (Areas 1 to 10) and higher yield devices in deeper holes on Pahute Mesa (Areas 

18 to 20). Tests at the Yucca Flat and Pahute Mesa sites had the same general requirements, but 

differed in the magnitude of the operations. Deeper hole operations disturbed a larger area, required 

more onsite equipment, and had higher requirements for electric power and utilities. The distance 

from NTS facilities and infrastructure was also a factor to minimize the effects of the tests. Pahute 

Mesa operations were 48 to 81 km (30 to 50 mi) farther away than Yucca Flat. 

Tests in Vertical Drill Holes and Drill Backs

The following paragraphs describe a vertical drill-hole test: 

1. Site Selection and Drilling – There were two options in site selection as it applied to a 

specific event – selection of an existing drill hole or selection of a new drill site from the 

Nuclear Test Zone. The goal of siting was to optimize the various parameters to attain 

operational feasibility and successful containment of yields.

A normal hole was from 1 to 3 m (39 to 120 in.) in diameter and from 213 to 762 m (600 to 

2,500 ft) deep. During drilling, samples of drill cuttings were collected at 3-m (10-ft) intervals, 

and rock cores were taken as required. After drilling was completed, geophysical instruments 

were run into the hole to evaluate its condition and gain a more thorough understanding of the 

geology. The drill site was secured by filling the sump and installing specially designed covers 

over the hole. 

2. Site Engineering and Construction – An area was cleared and leveled for the surface 

ground-zero equipment. Another area close by was cleared and leveled for the recording 
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trailer park. Onsite construction was temporary and abandoned after the test. Concrete pads 

were poured around the surface at ground zero to provide a stable platform for down-hole 

operations and a base for the assembly towers. Equipment was moved in to place the nuclear 

device in the hole, record the data, and provide radiological and seismic monitoring of the site. 

A circle of radiation detectors was placed back from the surface at ground zero to detect and 

assess releases from the experiment. A perimeter fence was erected, and access was 

controlled both to and from the site. 

3. Device Delivery and Assembly – For safety reasons, the nuclear device was delivered to the 

NTS unassembled. The device was assembled and inserted in a container in the Area 27 

Assembly/Staging Facilities. The device, now encased in the container, was delivered to the 

event site accompanied by armored convoy. It was attached to the diagnostics canister in 

preparation for placement in the hole. There was no radiation exposure potential above 

background environmental levels prior to this stage.

4. Diagnostic Assembly – A diagnostic canister or rack was assembled off the site and 

transported to the test site. A typical canister would have been about 2 m (8 ft) in diameter 

and 30 m (120 ft) long and would contain all the instrumentation required to receive data at the 

time of the explosion (real time). On arrival at the site, the diagnostic canister was installed in 

the assembly tower to be mated with the device. 

5. Emplacement of the Experiment – The drill hole was opened and the nuclear explosive and 

measurement devices were moved to the hole and lowered to the detonation position, along 

with diagnostic materials and instrumentation cables. The assembly was placed on a set of 

fracture-safe beams that spanned the opening. Any auxiliary equipment was lowered into the 

hole, and the area was secured. The hole was stemmed to prevent radioactive materials from 

escaping during or after the experiment. Areas around instrument cables were sealed to 

prevent a radioactive gas path to the surface.

6. Test Execution – Security operations began 2 d before the test to ensure that all 

non-event-related personnel were evacuated before the test for security and safety. The 

explosive was armed. Radiation monitors were activated, and aircraft with tracking capability 

circled the site in case gas and debris unexpectedly vented to the surface. Weather forecasts 

and fallout pattern predictions were reviewed. When acceptable weather conditions and other 

criteria were met, the device was detonated.

When an underground nuclear device was detonated, the energy released almost 

instantaneously produced extremely high temperature and pressure that vaporized the device 

and the surrounding rock. Within a fraction of a second after detonation, a generally spherical 

cavity was formed at the emplacement position. As the hot gases cooled, a lining of molten 

rock puddled at the cavity bottom. 

After a period of minutes to hours, as the gases in the cavity cooled, the pressure subsided 

and the weight of the overburden sometimes caused the cavity roof to collapse, producing a 

vertical, rubble-filled column known as a rubble chimney. The rubble chimney commonly 

extended to the surface, forming a subsidence crater. There are a number of subsidence 

craters on NTS. These craters generally are bowl-shaped depressions with diameters ranging 

from about 60 to 600 m (200 to 2,000 ft) and a depth ranging from a few to 60 m (200 ft), 

depending on the depth of burial and the explosive energy yield. Some deeply buried 

explosions of low yield formed cavities that did not collapse to the surface and, as a 

consequence, did not create subsidence craters. 
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After the test, ground zero remained secure until it was certain that the test had been 

contained. A reentry crew was dispatched to the site to retrieve data and note the condition of 

equipment. Reentries had the potential to cause significant external and internal radiation 

exposures, but a comprehensive radiological control program was in place. After all was 

secure, normal NTS operations resumed. Ground zero was roped off, outlining an exclusion 

zone if there was danger of potential cratering. 

7. Post-Shot Operations (Drill back) – After the temperature of the cavity had cooled, a 

post-test hole was usually drilled to the point of the explosion to retrieve debris samples. The 

highly radioactive samples provided important information on the test. The post-test hole was 

as small in diameter as possible and was drilled at an angle to allow the drill rig to be 

positioned safely away from the surface at ground zero. The drilling duration depended on 

multiple factors including the depth of the emplacement, size of device, equipment function, 

and matrix of the substrate. After drilling and sampling operations were complete, the drill rig 

and tools were decontaminated. Residual radiation was cleaned up at the site.

It was possible to encounter high gas pressures in the cavity because the drill back was often 

performed within 1 or 2 d of the detonation. In 1964, engineering devices were used to 

prevent the escape of radioactive gases and particulates. However, there was the potential for 

exposure to gaseous and particulate fission and activation products (REECo 1995). 

The pathways for release of radioactivity and personnel exposure were two-fold. The first 

scenario was based on a loss of containment in the drilling or coring operation. This occurred 

during routine drilling operations, or it could be caused by a failure of containment equipment. 

The radionuclides of concern for dose for this pathway were the fission products 85Kr, 131I, 133I, 

133mXe, and 137Cs. The second scenario was based on particulate fission or activation 

products in the core samples obtained after an underground test (REECo 1995). 

Although weapons tests have not been conducted since September 1992, in an effort to 

maintain readiness skills, drill-back operations have been occasionally conducted. Personnel 

involved in drill-back operations typically wear pocket dosimeters and full personal protection 

clothing (PPC). Those handling core samples wear extremity monitoring dosimeters (REECo 

1995). See Attachment D for additional information about post-test drilling.

2.3.3.2

Rainier Mesa in Area 12 was the site of the Nation’s first fully contained underground nuclear 

detonation, called RAINIER, on September 19, 1957, in a horizontal tunnel about 488 m (1,600 ft) into 

the mesa and 274 m (900 ft) beneath the top of the mesa. Of the 61 underground nuclear tests in 

Area 12 between late 1957 and 1992, only 2 were in drilled holes; the 59 others were in mined 

tunnels. By the early 1990s, there was only one active tunnel in use.

Tests in Mined Tunnels and Mine Backs

The tunnel tests evaluated the effects of nuclear weapons explosions, thermal radiation, blast, shock, 

X-rays, and gamma rays on military hardware such as communication equipment, rocket nose cones, 

and satellites. The typical horizontal-line-of sight (HLOS) test was designed to minimize blast and 

shock effects from the experiments. The large tunnel complex mined under the mesa contained 

HLOS pipe, which was about 460 to 550 m (1,500 to 1,800 ft) long and tapered from as much as 9 m 

(30 ft) in diameter at the test chamber to several inches at the working point. Experiments were 

placed in the pipe test chambers. At zero time, when the nuclear device was detonated, radiation 

flowed instantaneously down the pipe, creating the necessary radiation environment. To prevent 

bomb debris and blast from reaching and damaging the experiments, three mechanisms were used to 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 41 of 97

close the pipe; the first was the Fast Acting Closure, which was slammed shut by HE in about 1 ms; 

the other two closures followed within 30 and 300 ms.

A number of tunnels were mined into Rainier Mesa, in which most DOD HLOS exposure experiments 

occurred. In particular, the N-, P-, and T-Tunnel complexes were extensively developed during the 

past several decades. N-Tunnel was the location for a nonproliferation experiment, detonated in 

September 1993, which involved 1.3 x 106 kg (2.9 x 106 lb) of conventional HE. DOD currently 

operates an HE research and development tunnel in Area 12. This reusable test bed supports 

programs involving the detonation of conventional or prototype explosives and munitions. 

Routine Tunnel Operations – Routine tunnel operations had a potential for personnel exposure to 

fission or activation products that remained from tests conducted previously in the tunnel complex. 

These radioactive materials could be carried by water, or could seep through faults and fissures to 

reenter the working areas. Experience has shown that the external dose levels in routine tunnel work 

areas were very low. The principal radionuclides of external dose concern were the fission products 

90Sr/90Y and 137Cs (REECo 1995).

Containment Ponds – The containment ponds were constructed to catch contaminated runoff from 

the tunnel complexes. All active containment ponds are fenced and posted with radiological warning 

signs to prevent human access. Water contaminated with radionuclides seeped from the tunnels in 

Area 12 and was collected in the containment ponds, resulting in water evaporation and seepage into 

the soil. The tunnels have been sealed, but water continues to seep from E Tunnel. The only 

radiological contaminant that produces a measurable air emission from evaporation of the water is 3

H 

(as HTO). In 2001, an estimated 14 Ci of HTO were discharged to the ponds (DOE 2002a). Table 

2-4 lists the 1996 estimate.

Reentry and Mineback Operations – Reentry and mineback operations usually took place within 

days or weeks of an underground test. In some instances, they were conducted as much as decades 

after a test. These operations took place in a confined underground environment whereby personnel 

actually entered the test cavity. There were two exposure scenarios during reentry and minebacks. 

The first scenario was based on a loss of containment in the drilling or coring operation. This could 

occur during the routine drilling operations or be caused by a failure of containment equipment. The 

radionuclides of concern for this pathway were 54Mn, 90Sr, 90Y, 103Ru, 106Rh, 131I, 133I, 137Cs, and 182Ta 

(REECo 1995).

The second exposure scenario was the possibility of fission or activation products entering the 

working areas of the tunnels by migrating through fissures in the rock, by escaping through LOS pipes 

when they were opened to remove experiment equipment and samples, or by personnel actually 

entering the cavity. The radionuclides of concern for dose for this pathway were 60Co, 124Sb, 131I, 133I, 

and 137Cs. At present, no mineback or reentry operations are likely to be conducted at the NTS 

unless testing is resumed. If this occurs, personnel would wear whole-body TLDs, pocket dosimeters, 

and PPC (REECo 1995).

2.3.3.3

The LEDOUX nuclear test with a yield of less than 20 kt was conducted in 1990 in a drift in this tunnel 

complex. The dynamic KISMET experiment, involving HE, tritium, depleted uranium, and other 

materials, was conducted in the complex in March 1995. Both LEDOUX and KISMET were contained 

to prevent radiological releases to the rest of the complex and the surface environment.

U1a Subcritical Experiments
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2.3.3.4

Shallow borehole tests occurred between 1960 and 1968. Some of these tests were safety related; 

others were conducted as part of Project PLOWSHARE to determine if nuclear detonations could be 

used as a method for excavation. The shallow tests resulted in the development of some large 

ejection craters, most notably the SEDAN crater in the northern end of the Yucca Flat testing area. 

SEDAN, a 104-kt nuclear device detonated 194 m (635 ft) underground, displaced about 1.2 x 107 t of 

earth and created a crater 390 m (1,280 ft) in diameter and 98 m (320 ft) deep. The estimated 

remaining inventory of surface radioactivity at the SEDAN crater is 344 Ci. The total estimate for all 

releases from shallow borehole tests to the surface soil horizon at the NTS is 2,000 Ci. Radionuclides 

include isotopes of americium, cesium, cobalt, europium, plutonium, and strontium (DOE 1996a).

Shallow Borehole Tests

2.3.3.5

The containment of underground nuclear explosions was a process that continually evolved through 

learning, experimentation, and experience. The record of containment illustrates the various types of 

releases and their relative effects. Operational releases were small releases of radioactivity from the 

operational aspects of vertical drill hole tests. Activities that often resulted in operational releases 

included drilling back down to the location of the explosion to collect core samples, collecting gas 

samples from the explosion, and sealing the drill-back holes (OTA 1989).

Radioactive Releases from Nuclear Weapons Testing

Late-time seeps were small releases that occurred days or weeks after a test when gases diffused 

through pore spaces in the overlying rock and were drawn to the surface by decreases in atmospheric 

pressure.

Controlled tunnel purging was an intentional release of radioactive material to recover experimental 

equipment and ventilate test tunnels. During a controlled tunnel purging, gases from the tunnel were 

filtered, mixed with air to reduce the concentration, and released over time when weather conditions 

were favorable for dispersion into sparsely populated areas (OTA 1989).

Successful containment was defined as no radioactivity detectable off the site and no unanticipated 

release of radioactivity on the site. By definition, there has been containment failure on four 

occasions since 1970 (OTA 1989). Table 2-5 includes every instance (for both announced and 

unannounced tests) in which radioactive material reached the atmosphere under any circumstances 

whatsoever from 1971 to 1988. The lower part of Table 2-5 summarizes underground tests before 

1971 and provides a comparison with other releases of radioactive material. 

Operational Releases and Tunnel Purging – Past underground tests formed pockets of radioactive 

contamination around each test site. The source term includes many short- and long-lived 

radionuclides. For example, for atmospheric testing of a 1-kt nuclear weapon, an initial release of 41 

billion Ci decays to about 10 million Ci in just 12 hr. The quantity of radioactivity remaining from a 1-kt 

underground detonation 180 d after detonation is about 45,000 Ci (including 18,570 Ci of tritium). 

However, there is considerable uncertainty concerning these estimates. For example, the actual 

tritium activity after 180 d could range from 5,570 to 55,770 Ci (DOE 1996a).

Purging gases from the tunnel for testing occasionally resulted in releases of radioactivity, and 

contaminated water drained from the tunnels to containment ponds (DOE 2002a). While the tunnel 

complex was being secured before detonation of the nuclear device, the ventilation line was 

disconnected at each containment plug and the penetration through the plug was sealed. Therefore, 

it was necessary to reenter the tunnel to reestablish ventilation through the various containment plugs. 

If radioactive gases were present in a portion of the complex, it became necessary to purge these 
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Table 2-5. Releases from underground tests (normalized to 12 hr 

after event).

a,b

Release Events Ci released

All releases 1971–1988

Containment failures:

 CAMPHOR, 1971c 360

 DIAGONAL LINE, 1971 6,800

 RIOLA, 1980 3,100

 AGRINI, 1984 690

Late-time seeps:

 KAPPELLI, 1984 12

 TIERRA, 1984 600

 LABQUARK, 1986 20

 BODIE, 1986d 52

Controlled tunnel purgings:

 HYBLA FAIR, 1974 500

 HYBLA GOLD, 1977 0.005

 MINERS IRON, 1980 0.3

 HURON LANDING, 1982 280

 MINI JADE, 1983 1

 MILL YARD, 1985 5.9

 DIAMOND BEECH, 1985 1.1

 MISTY RAIN, 1985 63

 MIGHTY OAK, 1987 38,000

 MISSION GHOST, 1987d 3

Operation releases:

 108 tests from 1980-1988 5,500

Total since BANEBERRY: 54,000

Major pre-1971 releases:

 PLATTE, 1962 1,900,000

 EEL, 1962 1,900,000

 DES MOINES, 1962 11,000,000

 BANEBERRY, 1970 6,700,000

 28 others from 1958-1970 3,800,000

Total: 25,300,000

Other releases for reference:

 NTS atmospheric testing, 1951-1963 12,000,000,000

 1-kt aboveground explosion 10,000,000

 Chernobyl (estimate) 81,000,000

a. Source: OTA (1989).

b. R+12 values apply only to containment failures; others are at time of release.

c. The Camphor failure includes 140 Ci from tunnel purging.

d. BODIE and MISSION GHOST also had drill-back releases.

gases from the tunnel. The major potential for release of radioactive materials to the atmosphere 

existed during these purging operations. The purging resulted in release of noble gases (85Kr, 85mKr,

86Kr, 131mXe, 133Xe, 133mXe, and 135Xe) and small quantities of 131I and 133I. A release during this phase 

of the operation was typically of the order of 100 Ci or less of noble gases, with microcurie or millicurie 

quantities of radionuclides. Reentry drilling produced dust that was removed from the reentry heading 

by the tunnel ventilation system. This dust contained fission and activation products produced by 

neutron activation of the HLOS pipe. These releases were in the millicurie range (DOE 1995b).
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Unexpected Releases of Radioactivity – Although over 90% of all nuclear weapons tests occurred 

as predicted, the unexpected sometimes happened. In some cases, the failure resulted in the loss of 

experimental equipment or required the controlled ventilation of a tunnel system. In even more rare 

cases (3%), the failure resulted in the unintentional release of radioactive material to the atmosphere. 

The following information was taken from OTA (1989) unless otherwise noted.

1. BLANCA (October 30, 1958, horizontal tunnel test, 22 kt, radioactivity detected on the site). 

The test location was NTS U12e.05. Although BLANCA was detonated in a tunnel, it vented 

through the overburden into the atmosphere. Venting occurred at the edge of Rainer Mesa in 

Area 12. The ensuing cloud rose 580 ft above the mesa and drifted off in a westerly direction 

(DNA 1982b).

2. DES MOINES (June 13, 1962, horizontal tunnel test, 2.9 kt, radioactivity detected off the site). 

The test location was NTS U12j.01. Almost immediately after detonation, venting of 

radioactive effluents occurred at the surface, then from the vent hole, and finally through the 

portal. The release lasted approximately 5 min at a velocity of approximately 65 mph. The 

cloud direction was northeasterly over Queen City, Nevada (unpopulated). The maximum 

distance radiation was detected was at Ely, Nevada, 163 mi from the detonation site. The 

cause of the release was attributed to stemming failure around the device (DSWA 1997).

3. BANEBERRY (December 18, 1970, vertical shaft test, 10 kt, radioactivity detected off the site). 

The test location was NTS U8d. The BANEBERRY test resulted in a prompt massive venting. 

Radioactive material from BANEBERRY was tracked as far as the Canadian border. The 

cloud direction was northeasterly and moved over Nevada, Utah, and Wyoming. Another 

fraction moved toward California. The exact cause of the venting is unknown. The original 

explanation postulated the existence of an undetected water table, and the explanation 

assumed that the high temperatures of the explosion produced steam that vented to the 

surface. Later analysis, however, discredited this explanation and proposed an alternative 

scenario based on three geologic features of the BANEBERRY site: Water-saturated clay, 

buried scarp of hard rock, and a nearby fault. It is thought the energy of the explosion was 

unable to support the containment structure. The hard scarp strongly reflected the energy of 

the explosion, increasing the force, and the nearby fault provided a pathway along which 

gases could travel.

4. CAMPHOR (June 29, 1971, horizontal tunnel test, less than 20 kt, radioactivity detected only 

on the site). The test location was NTS U2g.10. The ground shock produced by the 

CAMPHOR test failed to close the HLOS pipe fully. After about 10 s, gases leaked through 

and eroded the stemming plug. As gases flowed through the stemming plug, pressure 

increased on the closure door behind the experiment. Gases leaked around the cable 

passageways and eroded a hole in the closure door. Pressure was then placed on the final 

door, which held but leaked slightly. The releases from the Cable Building lasted 30 min; the 

releases from the portal lasted 4 d.

5. DIAGONAL LINE (November 24, 1971, vertical shaft test, less than 20 kt, radioactivity 

detected off the site). The test location was NTS U11g. DIAGONAL LINE was conducted in 

the northern part of Frenchman Flat. It is speculated that carbonate material released CO2

gas that forced radioactive material to leak to the surface. The cloud direction was 

southwesterly toward the Amargosa Desert in Nevada. DIAGONAL LINE was the last test 

detonated on Frenchman Flat.
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6. RIOLA (September 25, 1980, vertical shaft test, less than 20 kt, radioactivity detected off the 

site). The test location was NTS U2eg. RIOLA exploded with only a small fraction of the 

expected yield. A surface collapse occurred and the failure of a containment plug resulted in 

the release of radioactive material.

7. AGRINI (March 31, 1984, vertical shaft test, less than 20 kt, radioactivity detected only on the 

site). The test location was NTS U2ev. The AGRINI test formed a deep subsidence crater 60 

ft west of the emplacement hole. A small amount of radioactive material was pushed through 

the chimney by noncondensible gas pressure and was detected on the site.

8. MIDAS MYTH (February 15, 1984, horizontal tunnel test, less than 20 kt, no release of 

radioactive material). The test location was U12t.18. All of the radioactive material produced 

by the MIDAS MYTH test was contained within vessel 1, with no release of radioactivity to 

either the atmosphere or the tunnel system. Three hr after the test, however, the cavity 

collapsed and the chimney reached the surface, forming an unanticipated subsidence crater. 

Equipment trailers were damaged, personnel were injured, and one person later died due to 

physical circumstances. There was no radiation exposure. 

9. MISTY RAIN (April 6, 1985, horizontal tunnel test, less than 20 kt, no unintentional release of 

radioactive material). The test location was U12n.17. MISTY RAIN is unusual in that it is the 

only tunnel test since 1970 that did not have three containment vessels. During the test, an 

early flow of energy down the HLOS pipe prevented the complete closure of the modified 

auxiliary closure doors. The doors overlapped, but stopped a couple of inches short of full 

closure. The tunnel and pipe seal (TAPS) door closed only 20% before the deformation from 

ground shock prevented it from closing. A small amount of radioactive material escaped down 

the pipe and then seeped into the bypass tunnel. The tunnel was later intentionally vented so 

equipment could be recovered.

10. MIGHTY OAK (April 10, 1986, horizontal tunnel test, less than 20 kt, no unintentional release 

of radioactive material). The test location was U12t.08. During the MIGHTY OAK test, the 

closure system near the working point was over-pressured and failed. The increased pressure 

and temperature from escaping gases caused both the MAC and the gas seal auxiliary closure 

to fail. The loss of the stemming plug near the working point left the tunnel an open pathway 

from the cavity. Temperatures and pressures on the closed TAPS door reached 2,000°F and 

1,400 psi. After 50 s, the center part (approximately 6 ft in diameter) of the TAPS door 

yielded. With the closures removed, the stemming column squeezed out through the tunnel. 

Radioactive material leaked from vessel I and vessel II and into vessel III, where it was 

successfully contained. About $32 million of normally recoverable and reusable equipment 

was lost. Controlled purging of the tunnel began 12 d after the test and continued 

intermittently from April 22 to May 19, when weather conditions were favorable. A total of 

36,000 Ci were released to the atmosphere during the period.

2.3.4

A number of activities occurred at the NRDS in Area 25. From 1959 to 1973, the area was used for a 

series of open-air nuclear reactor, nuclear engine, and nuclear furnace tests and for the High Energy 

Neutron Reactions Experiment. Equipment and facilities remain from some of these activities, and 

there are some limited areas of contaminated soils. The total estimated inventory of radionuclides 

remaining in the soils in this area is about 1 Ci (DOE 1996a). The primary soil contaminants are 

enriched uranium, strontium, cesium, cobalt, and europium. Because of aging and weathering, these 

materials have become relatively fixed.

Nuclear Reactor Development Tests
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The goal of the nuclear rocket engine test program was to develop an operational nuclear-powered 

rocket for space travel, given that the crew could be adequately protected from radiation produced by 

the engine. Ramjet exhaust dispersed radioactive material at the core as cladding degraded during 

operation of the engine. In a somewhat parallel program, the development of a nuclear ramjet engine 

began in 1957 in Area 26. Because the ramjet was designed as an air-breathing engine, it was 

visualized as being restricted to relatively low altitudes. The final reactor test was of a nuclear furnace 

with a replaceable core in a reusable test bed designed to provide an inexpensive approach to testing 

advanced fuels in full-scale reactor environments. The nuclear furnace was successfully tested in 

1972. Reactor-related tests ended in 1973.

Total releases by all rocket and ramjet engine tests amounted to about 834,000 Ci (DOE 1995a). As 

noted above the radionuclides 60Co, 90Sr/90Y, 137Cs, and 152Eu are of primary concern for dose. When 

entering into the rocket test areas, personnel wore whole-body TLDs (REECo 1995). Attachment B 

contains additional information for NRDS activities. Table B-2 identifies off-site releases for 

nuclear-powered rocket and ramjet engines.

2.3.5

2.3.5.1

Radioactive Waste Management Sites

DOE disposes of bulk low-level waste in seven selected Area 3 subsidence craters that collectively 

make up the Area 3 RWMS. This activity began in the mid-1960s when DOE began removing scrap 

tower steel, vehicles, and other large objects that had been subjected to atmospheric testing. From 

1979 to 1990, large amounts of contaminated soil and other NTS debris were added to the craters 

(DOE 1996a).

Crater Disposal – Area 3

Today, Area 3 is used for the disposal of bulk and packaged low-level waste from on- and offsite 

DOE-approved generators. Waste disposal cells at the Area 3 RWMS consisted of four subsidence 

craters (U-3ax, U-3bl, U-3ah, and U-3at) with areas between U-3ax and U-3bl and between U-3ah 

and U-3at excavated to make two oval landfill units. Conventional landfill methods are used to 

dispose of waste in each cell; each layer of waste is covered with 1 m (3 ft) of fill before additional 

waste materials are added. The inactive U-3ax/bl disposal cell contains low-level mixed waste. The 

U-3ah/at cell is used for low-level waste disposal; mixed waste is not accepted. Three additional 

subsidence craters (U-3bh, U-3bg, and U-3az) have been reserved for use as low-level waste cells. 

As of 1996, approximately 1,250 Ci had been disposed of in the Area 3 subsidence craters (DOE 

1996a). 

Because the low-level Area 3 RWMS is in a location where the surrounding surface soil has been 

contaminated by past nuclear tests, the resuspension of this soil by wind or vehicular activity results in 

the detection of above-background levels of plutonium in air samples collected inside and outside the 

perimeter fence (DOE 2002a).

Personnel working inside the RWMS wear whole-body TLDs and pocket dosimetry. Extremity 

monitoring and multiple dosimetry are required for some waste-handling work (REECo 1995).

2.3.5.2

The Area 5 RWMS uses pits and trenches for shallow land burial of standard packaged low-level 

waste. The category of low-level waste includes material that is classified because of its physical 

shape or specific composition. Classification creates a need for the use of separate disposal units 

controlled with additional security measures. 

Shallow Land Burial – Area 5 Low-Level
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In 1961, the Area 5 RWMS was established for the disposal of low-level waste, low-level mixed waste, 

and classified low-level waste from both on- and offsite generators. The waste area at the Area 5 site 

consists of 23 landfill cells (pits and trenches), 13 greater confinement disposal boreholes, as 

discussed below, and the transuranic waste storage pad (DOE 2002b). Approximately 500,000 Ci of 

low-level waste had been disposed of in Area 5 pits and trenches by 1996. High-specific-activity 

wastes were disposed of in the greater confinement disposal units.

The Area 5 RWMS is a diffuse source of radiological effluents. However, the only emission detected 

by the various types of samplers surrounding the site in 2001 and attributed to site operations was 

HTO in atmospheric moisture. Table 2-6 lists the estimated number of curies emitted from the source 

for 2001 (DOE 2002a). Personnel working inside the site wear whole-body TLDs, track-etch 

dosimeters (TEDs), and pocket dosimeters. Extremity monitoring is required for some waste-handling 

work (REECo 1995).

Table 2-6. Estimated curies emitted from the source for 2001.

a

Event Estimated Ci 

RWMS No. 4 6.5 

SEDAN crater 13

E Tunnel pond 11

SCHOONER crater 400

a. Source: DOE (2002a).

2.3.5.3

NTS adopted greater confinement burial [21 to 40 m (70 to 120 ft) deep] for wastes that are not 

appropriate for near-surface disposal due to their radioactive exposure levels. Material was disposed 

of from 1984 to 1989. The specific types of waste include certain high-specific-activity, low-level 

waste (for example, fuel rod claddings and sealed sources), TRU waste, and some classified material. 

The developed waste area in the Area 5 RWMS includes 13 greater confinement disposal boreholes.

Greater Confinement Disposal – Area 5

As of 1996, approximately 9.3 x 106 Ci of high-specific-activity waste, primarily tritium, had been 

disposed of in greater confinement disposal units in Area 5 (DOE 1996a). 

2.3.6

Radiological analyses were conducted in laboratories in Building 652 in Mercury and Building 

CP-95A, Building CP-50, and the Device Assembly Facility in Area 6. Because these facilities 

process environmental samples, very little radioactivity passes through them. However, there is 

potential for discharges of some radionuclides to the atmosphere from the hood ventilation system 

during sample processing, particularly of spiked samples, or from loss of radioactive standards in 

liquid or gaseous form. In the past, evaporation and spills from samples containing HTO, 

radioiodines, or noble gases were estimated conservatively by assuming all such materials were 

released even though they were not. In 2001, only actual emissions were reported; 5.6 Ci of tritium 

gas were used periodically during the year at Area 6 CP-50 to calibrate analytical equipment (DOE 

2002a).

Laboratories

Following the closure of the Analytical Services Laboratory in Building 650, all the standards, check 

sources, and tracer solutions were stored pending proper disposal of all items. Contamination can 

still be found in the fume hoods. An inventory of standards, check sources, and tracer materials 

indicates that three of them are volatile and could become a source of air emissions (DOE 2002a):
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3

H – 3.0 × 10-4 Ci

85Kr – 8.7 × 10-2 Ci

129I – 5.4 × 10-7 Ci

Table 2-4 lists the 1996 estimates.

The Los Alamos National Laboratory maintained standards of radioactivity containing 133Xe, 131I, and 

3

H in Building 701 at Mercury. Due to the test moratorium that began in 1992, the need for standards 

was reduced (DOE 2002a).

Sealed and uncontained radioactive sources are used for radiochemistry and sample-counting 

operations at the NTS. These low-level radioactive sources used as tracers and for instrument 

calibration present very little external dose potential. Laboratory personnel wear whole-body 

monitoring TLDs (REECo 1995).

2.3.7

Sealed radioactive sources are used for radiography at the NTS. The potential for external exposure 

is most likely to occur when the source is removed from the shield for radiography. The radionuclide 

currently used for radiography at the NTS is 192Ir, although 60Co can be used. Radiographers are 

required to wear whole-body TLDs, pocket dosimeters, and electronic alarming dosimeters (REECo 

1995).

Radiograph Operations

2.3.8

Sealed radioactive sources are a potential source of external exposure during well-logging operations 

at the NTS. Well logging is used to characterize drill holes and water movement. The radionuclides 

60Co, 131I, 137Cs, 226Ra, 228Th, 241Am, and 252Cf are used for well logging, and are of concern for dose. 

Well loggers routinely wear whole-body TLDs and pocket dosimeters when working with sources and 

sometimes wear extremity dosimeters. They also wear TEDs when working with neutron sources 

(REECo 1995).

Well-Logging Operations

2.3.9

The Treatability Test Facility is a pilot project to bench-test technologies for decontamination of soils 

that contain TRU materials. Techniques used to separate the radionuclides from the soil include both 

gravimetric separation and separation based on other properties of the material. The concentrations 

of radionuclides in the soil are unlikely to exceed a few picocuries per gram of soil. Therefore, 

external exposures to personnel are not likely to represent any unusual exposure control 

requirements (REECo 1995).

Treatability Test Facility

2.3.10

Equipment, materials, PPC, and devices used in nuclear weapons testing operations can become 

contaminated with radioactive material. These items are decontaminated on location or are 

transported to the decontamination facility in Area 6 where the contamination is removed from the 

material or equipment. Decontamination methods include washing with high-pressure water, 

submersion in chemical dip tanks, and use of other nonhazardous material solvents. Many different 

radionuclides can be present at the decontamination facility because contaminated items can come 

from any operations at the NTS. Decontamination of material is normally delayed until after decay of 

short-lived radionuclides (REECo 1995).

Decontamination Facility
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2.3.11

Sealed radioactive sources are used to calibrate instruments that detect radioactive materials. The 

sources are controlled and leak-tested as required by standard DOE radiological control practices. 

The potential for external exposure comes from the use of the sources during calibration and testing 

operations. In general, the sources are operated remotely, and personnel are removed from the 

calibration range during source exposure periods. The radionuclides 60Co, 90Sr, 90Y, 137Cs, 226Ra, 

227,228Th, 241Am, and PuBe (neutron) could contribute to the external dose at these facilities. The 

routine method of monitoring the external radiation exposure at the instrument calibration facilities is 

with the whole-body TLD and pocket dosimeter. Neutron TEDs are required for personnel using 

neutron sources (REECo 1995).

Radiation Instrument Calibration Facilities

2.3.12

Sealed radioactive sources, in addition to the radiography, well-logging, and instrument calibration 

sources are stored in a few buildings at the NTS. These sources belong to other organizations, and 

NTS stores them for future use. Because only a few are currently in use, the potential for external 

exposure is of very short duration during source inventory (REECo 1995).

Radioactive Source Storage Areas

2.3.13

The Nuclear Explosive Assembly Facility (NEAF) was built for the assembly of nuclear weapons 

components. The DAF was completed in 1992 and was built for future assembly or disassembly of 

nuclear weapon components. The potential external exposure at these facilities is high because 

significant quantities of radionuclides of concern for external exposure could be present. When the

NEAF is in operation, personnel wear whole-body monitoring TLDs, (track-etch dosimeters (TEDs), 

and extremity dosimeters when appropriate. 

Nuclear Explosive Assembly and Device Assembly Facility

2.4 RADIOLOGICAL ACCESS CONTROLS

NTS training material from the 1950s included the following basic radiation protection rules: 

• Personnel metering equipment will be worn at all times.

• Appropriate protective clothing and equipment will be worn when working in contaminated 

areas or with contaminated material.

• All radioactive material will be monitored by the Radiological Safety Division before shipped 

from the NTS.

• Personnel monitoring will be performed following exit from any contaminated area.

• Eating or storing of food or beverages will not be allowed in a contaminated area.

• Smoking is prohibited in contaminated areas.

Personnel exposures were minimized by the basic principles of time, distance, and shielding with 

access controls developed to support these rules and principles. RADEX areas were defined, a 

limited RADEX area required personnel protective clothing and monitoring support, and contaminated 

areas required access permits issued by Rad-Safe. Areas with radioactive materials or contamination 

were posted and access to such areas was controlled. Radiological Work Permits were issued to 
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establish controls for work activities within radiological areas. Permits included a review of the 

radiological conditions, personnel dosimetry requirements, training and protective equipment 

requirements for entry, allowable stay times, and the level of Rad-Safe coverage required. Training 

programs were developed at NTS to include General Employee Radiological Training, Radiological 

Worker I, Radiation Worker II, and Radiological Control Technicians (monitors).

Initially, the limits were those published in the National Bureau of Standards (NBS) Handbook # 59, 

Permissible Dose from External Sources of Ionizing Radiation (1954) and NBS Handbook # 52, 

Maximum Permissible Amounts of Radioisotopes in the Human Body and Maximum Permissible 

Concentrations in Air and Water (1953). Following the NBS Handbooks, various other programmatic 

documents governed the radiation protection program at NTS (e.g., AEC 1961, DOE 1988, and DOE 

1994). While the limits have changed over the years, the basic principles for posting areas, issuing 

work permits, completing training programs, and use of personal protective equipment have 

remained. The radiation protection program at the NTS is currently regulated under 10 CFR 835. 

Additional details for radiological access controls are found in the environmental, internal, and 

external sections of this site profile.

2.5 ATTRIBUTIONS AND ANNOTATIONS

All information requiring identification was addressed via references integrated into the reference 

section of this document.
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REFERENCES 

AEC (U.S. Atomic Energy Commission), 1958, Background Information on Los Alamos and Livermore 

Nuclear Propulsion Projects, and the Static Test Areas Being Developed at AEC’s Nevada 

Test Site: General Purpose and History, NV0078616, Los Alamos National Laboratory, Los 

Alamos, New Mexico.

AEC (U.S. Atomic Energy Commission), 1961, Radiological Safety, Nevada Test Site Organization 

(NTSO), Chapter 0524, NTSO-0524-01, Las Vegas, Nevada.

AEC (U.S. Atomic Energy Commission), 1972, TORY IIC Fact Sheet, NV0173546, Lawrence 

Livermore National Laboratory, Livermore, California.

Butler, M. W., 1984, Post-test Drilling Handbook, M-148, Lawrence Livermore National Laboratory, 

Livermore, California.

DNA (Defense Nuclear Agency), 1982a, Operation Hardtrack II, 1958, DNA-6026F, Washington, D.C.

DNA (Defense Nuclear Agency), 1982b, Operation Buster Jangle, 1952, DNA-6023F, Washington, 

D.C.

DOE (U.S. Department of Energy), 1995a, Radiological Effluents Released from Nuclear Rocket and 

Ramjet Engine Tests at the Nevada Test Site 1959 Through 1969 Fact Book, DOE/NV-401, 

UC-702, Nevada Operations Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 1995b, National Emission Standards for Hazardous Air Pollutants 

Submittal – 1994, DOE/NV/11432-194UC600, Nevada Operations Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 1996a, Final Environmental Impact Statement for the Nevada Test 

Site and Off-site Locations in the State of Nevada, DOE/EIS-0243, Nevada Operations Office, 

Las Vegas, Nevada.

DOE (U.S. Department of Energy), 1996b, Radiological Effluents Released from U.S. Continental

Tests 1961 Through 1992, DOE/NV-317, UC-702, Nevada Operations Office, Las Vegas, 

Nevada.

DOE (U.S. Department of Energy), 1997a, Nevada Test Site Annual Site Environmental Report for 

Calendar Year 1996, DOE/96NV11718, Nevada Operations Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 1997b, National Emission Standards for Hazardous Air Pollutants 

Submittal – 1996, DOE/NV/11718-116UC600, Nevada Operations Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 1988, Radiation Protection for Occupational Workers, Order 

5480.11, Washington, DC.

DOE (U.S. Department of Energy), 1994, NV/YMP Radiological Control Manual, DOE/NV/10630-59, 

Nevada Operations Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 2000a, United States Nuclear Tests, July 1945 through September 

1992, DOE/NV-209 (Rev. 15), Nevada Operations Office, Las Vegas, Nevada.
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DOE (U.S. Department of Energy), 2000b, Nevada Test Site Contaminated Land Areas Report, 

Volumes I and II, DOE/NV/1178-481, Nevada Operations Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 2002a, Nevada Annual Site Environmental Report for Calendar 

Year – 2001, DOE/NV 11718-747, Nevada Operations Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 2002b, National Emission Standards for Hazardous Air Pollutants 

Calendar Year 2001, DOE/NV/11718-719, Nevada Operations Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 2000c, Corrective Action Investigation Plan for Corrective Action 

Unit 127: A-25 and A-26 Storage Tanks, Nevada Test Site, DOE/NV-833, Nevada Operations 

Office, Las Vegas, Nevada.

DOE (U.S. Department of Energy), 2004, Appendices to the Federal Facility Agreement and Consent 

Order, Index of Corrective Action Investigation Units, Nevada Operations Office, Las Vegas, 

Nevada.

DSWA (Defense Special Weapons Agency), 1997, Operations Nougat, Flintlock, Latchkey, Bowline, 

and Emery: Events DES MOINES, TAPESTRY, AJAX, CYPRESS and CAMPHOR, 13 June 

1962 – 5 December 1971, DNA-6326F, Alexandria, Virginia.

Eberhart, C. F., 1993, “Post-test Drilling Operations and Responsibilities, March 1990 Edition,“ 

attachment to Hazard Analysis for LANL Drillback Operation at the Nevada Test Site, Los 

Alamos National Laboratory, Los Alamos, New Mexico.

EG&G Energy Measurements, 1994, data on disk from 1992 and 1994 aerial surveys, Remote 

Sensing Laboratory, Nevada Operations Office, Las Vegas, Nevada.

Johnson, W., J. Cramer, B. Thompson, and W. Sitko, 1966, Post-test Drilling Handbook, UCID-15034, 

Lawrence Livermore National Laboratory, Livermore, California.

LANL (Los Alamos National Laboratory), 1986, Experience Gained from the Space Nuclear Rocket 

Program (ROVER), LA-10062-H, Los Alamos Scientific Laboratory, Los Alamos, New Mexico.

McArthur, R. D., 1991, Radionuclides in Surface Soil at the Nevada Test Site, DOE/NV/10845-02, 

Water Resources Center, Desert Research Institute, University of Nevada, Las Vegas, 

Nevada.

NAS (National Academy of Science), 1989, Committee on Film Badge Dosimetry in Atmospheric 

Nuclear Tests, Film Badge Dosimetry in Atmospheric Nuclear Tests, Washington, DC: 

National Academy Press.

NASA (National Aeronautics and Space Administration), 1991, Overview of Rover Engine Tests, 

NV0333577, Marshall Space Flight Center, Alabama.

NBS (National Bureau of Standards), 1953, Maximum Permissible Amounts of Radioisotopes in the 

Human Body and Maximum Permissible Concentrations in Air and Water, NBS Handbook 52, 

Washington, D.C.

NBS (National Bureau of Standards), 1954, Permissible Dose from External Sources of Ionizing 

Radiation, NBS Handbook 59, Washington, D.C.
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 53 of 97

NDEP (Nevada Division of Environmental Protection), 2000, Federal Facility Agreement and Consent 

Order, Rev. 1, Appendix VI, Corrective Action Strategies, Carson City, Nevada.

ORAUT (Oak Ridge Associated Universities Team), 2007, Site Profile for Sandia National 

Laboratories in Albuquerque, New Mexico, and the Tonopah Test Range, Nevada, ORAUTTKBS-0037, Rev 00.

OTA (Office of Technology Assessment), 1989, The Containment of Underground Nuclear 

Explosions, OTA-ISC-414, Washington, D.C.

REECo (Reynolds Electrical and Engineering Company) 1961a, On-Site Radiological Safety Basic 

Support Plan for Reactor Tests at the Nevada Test Site, Las Vegas, Nevada.

REECo (Reynolds Electrical and Engineering Company), 1961b, Standard Operating Procedures for 

the Radiological Safety Division, Las Vegas, Nevada.

REECo (Reynolds Electrical and Engineering Company), 1993, Technical Basis for Internal Dosimetry 

at the Nevada Test Site, DOE/NV/10630-64, Mercury, Nevada.

REECo (Reynolds Electrical and Engineering Company), 1995, External Dosimetry Technical Basis 

Manual for the Nevada Test Site and Other Designated Locations, Las Vegas, Nevada.

S. Cohen & Associates, 2005, Advisory Board on Radiation and Worker Health, Review of the NIOSH 

Site Profile for the Nevada Test Site, SCA-TR-TASK1-0006, McLean Virginia.

Shockley, V., 2005, “Personal communication with F. M. Meier,” memorandum to file, Oak Ridge 

Associated Universities, Oak Ridge, Tennessee.
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 54 of 97

GLOSSARY (DOE 2000a) 

atmospheric 

A test conducted aboveground or above water (i.e., in the open air). The last atmospheric test 

at NTS was in 1962.

borehole number

The alpha-numeric designation is given to the nuclear weapon test or detonation. The 

uppercase alpha designator refers to the type of location: S = surface, U = underground. The 

numeric designator refers to the geographical area of the Nevada Test Site. The remaining 

letters refer to the sequential ordering of the test or detonation. In the case of most 

atmospheric tests, only the geographical area of the Nevada Test Site is given.

cementback 

Operation in which the drill hole is sealed with a plug and cemented to the surface after a shaft 

drill back.

containment failure

Unintentional release of radioactive material to the atmosphere due to a failure of the 

containment system. Called venting if it is a prompt, massive release; or seep if it is a slow, 

small release that occurs soon after the test. 

controllable area

An area in which remedial actions are feasible. The DOE criteria for a controllable area are 

“... areas where trained rad-safe monitors are available, where communications are effective 

(where the exposure of each individual can be documented), where people can be expected to 

comply with recommended remedial actions, and where remedial actions against uptake of 

radionuclides in the food chain are practicable.” This equates to a zone of approximately 125 

mi from the test CP. 

controlled release

A planned, filtered release performed to reduce airborne radiation levels in the tunnel working 

environment.

controlled tunnel purging

An intentional release to allow recovery of experimental data and equipment or reuse of part of 

the tunnel system. 

crater 

A nuclear device placed shallowly enough underground to produce a throw-out of earth when 

exploded.

detonation 

A single nuclear device explosion; a test or test series consists of one or more detonations.

drill back 

Directional drilling operation performed after a shaft test to sample fission product materials in 

the test cavity. Drill back operations after a shaft test were often performed within 1 or 2 d of 

the detonation.
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 55 of 97

gas sampling 

Operation usually performed after test activities have ceased to determine levels of noble 

gases present.

Gravel Gertie

A round room with 2-ft-thick concrete walls and a staging area with two staging bays 

connected to the round room. Tests were conducted in the Gravel Gertie with HE and 

uranium devices to measure fallout. Gravel Gerties are located in A-5 (GMX) and A-6 (DAF).

greater confinement boreholes 

From 1984 to 1989, DOE conducted intermediate-depth disposal operations at the NTS. 

These operations emplaced high-specific-activity, low-level radioactive wastes and limited 

quantities of classified TRU wastes in greater confinement boreholes. The boreholes are 

about 3 m (10 ft) in diameter and 36 m (120 ft) deep. The bottom 15 m (50 ft) of each 

borehole was used for waste emplacement and the upper 21 m (70 ft) was backfilled with 

native alluvium.

gross beta 

Measure of the total beta activity.

h 

A code that indicates Hour Detonation time (zero hour), which is the time a device was 

detonated.

kiloton (kt)

In relation to a nuclear detonation, an amount of energy equivalent to the explosive power of 

1,000 tons of TNT.

late-time seeps

Small releases that occur days or weeks after a test when gases diffuse through pore spaces 

in the overlying rock and are drawn to the surface by decreases in atmospheric pressure. 

From DOE (1996b): A slow release of gases from test detonation sites that could exist from a 

few hours to even weeks after all other operations in the area have ceased.

megaton (Mt)

In relation to a nuclear detonation, an amount of energy equivalent to the explosive power of 

1 million tons of TNT.

operational release

Small consequential releases that occur when core or gas samples are collected or when the 

drill back hole is sealed. 

PLOWSHARE Program

Application of nuclear explosives to develop peaceful uses for atomic energy at NTS and other 

locations. REECo provided support to the program, including offsite locations. The 

PLOWSHARE tests were: 

1. GNOME 12/10/61 Carlsbad, NM (shaft) 

2. SEDAN 07/06/62 NTS (crater) 

3. ANACOSTIA 11/27/62 NTS (shaft) 

4. KAWEAH 02/21/63 NTS (shaft) 

5. TORNILLO 10/11/63 NTS (shaft) 

6. KLICKITAT 02/20/64 NTS (shaft) 

7. ACE 06/11/64 NTS (shaft) 

8. DUB 06/30/64 NTS (shaft) 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 56 of 97

9. PAR 10/09/64 NTS (shaft) 

10. HANDCAR 11/05/64 NTS (shaft) 

11. SULKY 12/18/64 NTS (shaft) 

12. PALANQUIN 04/14/65 NTS (crater) 

13. TEMPLAR 03/24/66 NTS (shaft) 

14. VULCAN 06/25/66 NTS (shaft) 

15. SAXON 07/28/66 NTS (shaft) 

16. SIMMS 11/05/66 NTS (shaft) 

17. SWITCH 06/22/67 NTS (shaft) 

18. MARVEL 09/21/67 NTS (shaft) 

19. GASBUGGY 12/10/67 Farmington, NM

(shaft) 

20. CABRIOLET 01/26/68 NTS (crater) 

21. BUGGY-A to E 03/12/68 NTS (crater) 

22. STODDARD 09/17/68 NTS (shaft) 

23. SCHOONER 12/08/68 NTS (crater) 

24. RULISON 09/10/69 Grand Valley, CO 

(shaft) 

25. FLASK-GREEN, YELLOW, and Red 

05/26/70 NTS (shaft) 

26. MINIATA 07/08/71 NTS (shaft) 

Radex areas

During the testing era in a Full Radex Area, radiological contamination was greater than or 

equal to 100 mR/hr (gamma) measured 3 ft from the ground (more than 1 × 104 cpm/55 cm2

) 

(alpha surface contamination measured by portable alpha survey meter). No one was allowed 

into a Full Radex Area unless accompanied by a certified monitor who remained with or near 

the personnel during the entire period. In a Limited Radex Area, radiological contamination is 

greater than or equal to 10 mR/hr but less than 100 mR/hr (gamma) measured 3 ft from the 

ground (greater than or equal to 1 × 103 and less than or equal to 1 × 104 cpm/55 cm2 ) alpha 

surface contamination measured by portable alpha survey meter). No one was allowed into a 

Limited Radex Area unless accompanied by a certified monitor who would initially survey the 

area and return periodically to check radiological conditions. 

reentry

In the context of NTS operations over the entire period of weapons testing, the first entry into 

an area or tunnel following a nuclear detonation (which usually occurs as soon as safety 

limitations will permit). Reentry to retrieve experimental data was under the control and 

responsibility of the Technical Director assigned by the Test Manager and was performed by 

workers previously identified in the test documentation. Reentry does not cover cleanup 

operations or preparation for a detonation. Tunnel reentry and mineback operations usually 

took place within days or weeks of an underground test. 

safety experiment 

Experiment designed to confirm a nuclear explosion will not occur in case of an accidental 

detonation of the explosive associated with the device. 

seep

Uncontrolled slow release of radioactive material with little or no energy. Seeps are not visible 

and can be detected only by radiation monitoring. 

shaft test

A nuclear device exploded at the bottom of a drilled or mined vertical hole. The hole depth 

and diameter were dictated by the projected yield and diagnostics. Typical hole depths ranged 

from 600 to 2200 ft and typical hole diameters ranged from four to 10 ft. 

Special Nuclear Material

Plutonium or enriched uranium. 
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 57 of 97

stemming

Placement of materials such as grout, magnetite, bentonite, sand, and other materials to 

contain the nuclear explosion in a tunnel or shaft. 

surface test

A nuclear device placed on or close to the Earth's surface.

test 

A test is defined in the Threshold Test Ban Treaty as either a single underground nuclear 

explosion at a site or two or more underground nuclear explosions within a circle having a 

diameter of 2 km and within 0.1 s.

ton 

In relation to a nuclear detonation, an amount of energy equivalent to the explosive force of 

1 ton (2,000 lb.) of TNT.

tower test

A nuclear device mounted at the top of a steel or wooden tower and exploded in the 

atmosphere.

Trinity glass debris

Vitrified material created during a test that contains radioactive material. In general, there is 

no removable radioactive contamination, but the material can represent an external hazard. At 

NTS, this material usually looks like a rough piece of black charcoal or perhaps like the 

outcrop of a lava flow; it is usually not glassy in appearance.

tunnel test

A nuclear device exploded at the end of a long horizontal drift mined into a mountain or mesa 

in a way that places the burst point deep within the earth.

uncontrolled release

A spontaneous release occurring after a test but before post-test drilling operations 

commence. For DOE (1996b), this term is used when referring to tunnel tests.

underground test

Underground nuclear test conducted in a tunnel or at the bottom of a drilled hole or shaft. 

Some underground nuclear tests were not designed to contain all radioactivity (e.g., cratering 

tests or safety experiments).

venting

Prompt, massive, uncontrolled releases of radioactive material. Ventings are characterized as 

active releases under pressure, such as when radioactive material is driven out of the ground 

by steam or gas. 

weapons effects

A nuclear test to evaluate the civil or military effects of a nuclear detonation on various targets 

such as military hardware.

weapons related

A nuclear detonation conducted for the purpose of testing a nuclear device intended for a 

specific type of weapon system.
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 58 of 97

yield

The total effective energy released in a nuclear explosion. It is usually expressed in terms of 

equivalent tonnage of TNT required to produce the same energy release in an explosion.
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 59 of 97

ATTACHMENT A

TESTS BY YEAR, TYPE, AND LOCATION

Page 1 of 3

Table A-1. Tests by year, type, and location.

YEAR TYPE A-1* A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-10 A-11 A-12* A-15* A-16* A-18 A-19 A-20 A-30 TOTAL

1951 Atmospheric - - - - 5 - 5 - 1 - - - - - - - - - 11

UG-Crater - - - - - - - - - 1 - - - - - - - - 1

1952 Atmospheric 1 2 1 1 1 - 3 - - - - - - - - - - - 9

1953 Atmospheric 1 - 2 2 2 - 4 - - - - - - - - - - - 11

1955 Atmospheric 2 1 2 1 1 - 4 - 2 - 3 - - - - - - - 16

UG-Crater - - - - - - - - - 1 - - - - - - - 1

1956 Atmospheric - - - - - - - - - - 1 - - - - - - - 1

1957 Atmospheric 1 4 5 1 1 - 6 - 7 1 - - - - - - - - 26

UG-Shaft - - 3 - - - - - - - - - - - - - - - 3

UG-Tunnel (B,C) - - - - - - - - - - - 2 - - - - - - 2

1958 Atmospheric - - 4 - 3 - 9 3 5 - - - - - - - - - 24

UG-Shaft - - 6 - - - - - - - - - - - - - - - 6

UG-Tunnel (B,C,D,E,F) - - - - - - - - - - - 9 - - - - - - 9

1961 UG-Shaft - - 5 - - - - - 1 - - - - - - - - - 6

UG-Tunnel (B,E) - - - - - - - - - - - 3 - - - - - - 3

1962 Atmospheric - - - - 1 - - - - - - - - - 2 - - - 3

UG-Shaft - 1 26 - - - - - 23 1 - - 1 - - - - - 52

UG-Tunnel (12G,12J,12K,16A) - - - - - - - - - - - 3 - 1 - - - - 4

UG-Crater - - - - - - - - - 1 - - - - 2 - - - 3

1963 UG-Shaft - 7 20 - - - - - 14 1 - 1 - - - - - - 43

UG-Tunnel (B) - - - - - - - - - - - 1 - - - - - - 1

1964 UG-Shaft - 7 18 1 - - 2 - 13 7 - - - - 1 - - - 49

1965 UG-Shaft - 7 12 3 2 10 1 - - - - - 1 - 36

UG-Tunnel (15E,16A) - - - - - - - - - - - - 1 1 - - - - 2

UG-Crater - - - - - - - - - - - - - - - - 1 - 1

1966 UG-Shaft - 8 13 - 1 - 5 1 4 6 2 - - - - 2 3 - 45

UG-Tunnel 

(12G,15A,16A)

- - - - - - - - - - - 1 1 1 - - - - 3

1967 UG-Shaft - 8 13 1 - - 3 - 1 11 - - - - - 1 1 - 39

UG-Tunnel (G,N) - - - - - - - - - - - 2 - - - - - - 2

1968 UG-Shaft - 17 21 - 1 1 - - 5 8 1 - - - - 4 3 - 61

UG-Tunnel 

(12E,12N,16A)

- - - - - - - - - - - 2 - 1 - - - - 3

UG-Crater - - - - - - - - - - - - - - - - 2 5 7

1969 UG-Shaft - 20 20 - - - 4 - 4 4 1 1 - - - - 3 - 57

UG-Tunnel (E,G) - - - - - - - - - - - 2 - - - - - - 2

1970 UG-Shaft - 10 16 - - - 3 2 19 3 - - - - - - 1 - 54

UG-Tunnel 

(12E,12N,12T,16A)

- - - - - - - - - - - 3 - 1 - - - - 4 

1971 UG-Shaft 1 5 12 - - - - - 4 2 1 - - - - - - - 25

UG-Tunnel (12G,16A) - - - - - - - - - - - 1 - 1 - - - - 2
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 60 of 97

ATTACHMENT A

TESTS BY YEAR, TYPE, AND LOCATION

Page 2 of 3

YEAR TYPEA-1*A-2A-3A-4A-5A-6A-7A-8A-9A-10A-11A-12*A-15*A-16*A-18A-19A-20A-30 TOTAL

1972 UG-Shaft - 8 12 - - - 2 - 5 2 - - - - - - - - 29

UG-Tunnel (N,T)-----------2------2

1973 UG-Shaft-68---2-22-----1-- 21

UG-Tunnel (E,N)-----------2------2

1974 UG-Shaft-893--1--3-------- 24

UG-Tunnel (N)-----------2------2

1975 UG-Shaft-441--2-22-----33- 21

UG-Tunnel (E,T) - - - - - - - - - - - 2 - - - - - - 2

1976 UG-Shaft-521--5--1-----33- 20

UG-Tunnel (N)-----------1------1

1977 UG-Shaft - 5 8 2 5 2 2 - - - - - - - - 24

UG-Tunnel (E)-----------1------1

1978 UG-Shaft-323--4211-----41- 21

UG-Tunnel (N) - - - - - - - - - - - 1 - - - - - - 1

1979 UG-Shaft-443--2--1-----11- 16

1980 UG-Shaft-35---211------13- 16

UG-Tunnel (N)-----------1------1

1981 UG-Shaft-332--4211-----1-- 17

1982 UG-Shaft-143--2111-----22- 17

UG-Tunnel (N)-----------2------2

1983 UG-Shaft - 7 4 1 - - 2 - 1 1 - - - - - 1 1 - 18

UG-Tunnel (N)-----------2------2

1984 UG-Shaft-454--2-12-----12- 21

UG-Tunnel (T)-----------1------1

1985 UG-Shaft-142--21-------13- 14

UG-Tunnel (N)-----------3------3

1986 UG-Shaft-222--1--------34- 14

UG-Tunnel (T)-----------1------1

1987 UG-Shaft-14--11--4-----12- 14

UG-Tunnel (N,P,T)-----------3------3

1988 UG-Shaft - 3 3 2 - 3 - 2 - - - - - - - 2 2 - 17

UG-Tunnel (N)-----------1------1

1989 UG-Shaft-324--2--------13- 15

UG-Tunnel (P) - - - - - - - - - - - 1 - - - - - - 1

1990 UG-Shaft211--1---------12-8

UG-Tunnel (N)1----------2------3

1991 UG-Shaft--14--1--------12-9

UG-Tunnel (P)-----------1------1

1992 UG-Shaft--2-----3------1--6

UG-Tunnel (N,P)-----------2------2

TOTAL9 169 288 44 196 92 15 133 719 62365 36 495 1,021
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 61 of 97

ATTACHMENT A

TESTS BY YEAR, TYPE, AND LOCATION

Page 3 of 3

Table A-2. NTS testing intervals. 

Year

Number of 

NTS tests

Maximum 

interval between 

tests

Minimum 

interval between 

tests

Average interval 

between tests

Standard 

deviation Mode Median

1951 11 258 1 28 77 1 4

1952 8 124 4 24 41 7 8

1953 11 285 5 33 84 7 7

1954 No NTS tests N/A N/A N/A N/A N/A N/A

1955 16 624 1 55 157 6 6

1956 1 74 74 74 N/A N/A 74

1957 30 496 1 23 90 3 4

1958 26 182 1 13 38 2 2

1959 No NTS tests N/A N/A N/A N/A N/A N/A

1960 No NTS tests N/A N/A N/A N/A N/A N/A

1961 9 1051 1 0 0 0 0

1962 58 28 1 6 5 6 6

1963 32 56 1 12 12 8 8

1964 42 32 1 9 9 7 7

1965 35 56 1 10 11 1 7

1966 43 28 1 8 7 6 6

1967 37 29 1 10 8 6 7

1968 47 34 1 8 6 5 7

1969 31 34 1 11 7 8 8

1970 29 109 1 13 20 1 7

1971 19 180 1 19 40 1 7

1972 22 35 2 14 9 22 13

1973 18 96 1 18 23 1 13

1974 22 48 1 16 11 11 15

1975 20 72 1 18 19 7 11

1976 18 56 2 17 15 8 13

1977 17 56 3 21 15 8 20

1978 17 61 5 22 16 14 15

1979 16 64 2 23 19 15 17

1980 16 76 6 23 19 6 17

1981 17 64 1 20 15 20 20

1982 16 64 1 22 18 8 18

1983 17 71 1 22 22 8 14

1984 19 46 1 19 12 15 15

1985 16 85 3 23 21 41 17

1986 15 84 2 23 20 29 19

1987 15 52 1 20 17 8 11

1988 14 75 1 26 21 N/A 24

1989 11 79 6 28 24 N/A 15

1990 9 80 4 33 29 N/A 27

1991 8 121 5 47 45 N/A 30

1992 6 121 4 50 46 N/A 43
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 62 of 97

TABLE OF CONTENTS 

SECTION TITLE

B.1 Introduction ...............................................................................................................................

PAGE

62

B.2 Area 400 Major Facilities ..........................................................................................................62

B.3 ROVER .....................................................................................................................................65

B.3.1 Project Reactor and Engine Tests ............................................................................... 67

B.4 PLUTO......................................................................................................................................70

B.4.1 Area 401 Major Facilities.............................................................................................. 70

B.4.2 TORY Reactor Tests.................................................................................................... 71

B.5 Summary of Radiological Hazards............................................................................................73

B.5.1 External Exposure........................................................................................................ 73

B.5.2 Internal Exposure......................................................................................................... 73

B.6 Onsite Radiological Support for Reactor Tests.........................................................................73

B.1 Introduction

Nuclear rocket and ramjet engine tests were conducted at the Nuclear Rocket Development Station 

(NRDS, now the Nevada Research and Development Area) in Area 25 and Area 26, about 80 mi 

northwest of Las Vegas, Nevada. One section of the Jackass Flats Area was designated as the 400 

Area for Los Alamos Scientific Laboratory (LASL; now known as LANL) operations associated with 

the ROVER and the Nuclear Engine for Rocket Vehicle Application (NERVA) tests, while the other 

was designated as the 401 Area for Lawrence Radiation Laboratory (LRL) operations associated with 

the PLUTO Ramjet Engine Tests (Figure B-1). The ROVER nuclear rocket test program began with 

Project KIWI—a reactor test on July 1, 1959—and culminated with the Nuclear Furnace (NF-1) test 

June 1 1972. In January 1973, the ROVER nuclear engine project was terminated due to changing 

priorities even though it was judged a technical success.

B.2 Area 400 Major Facilities

The 400 Area had three major groups of buildings and facilities with supporting roads, water wells and 

lines, smaller buildings, railroad tracks, electric power supply lines and transformers, and a tank farm 

(Figure B-2). The three major building groups were (AEC 1958):

Control Building Area – The reinforced concrete Control building, with a floor area of about 9,700 ft2

, 

housed the controls and instruments for operating and recording tests performed in the Test Cell area. 

Other buildings in the same area included a generator station for standby power, an administration 

building, two warehouses, a cafeteria, and a small guardhouse. These were constructed of steel and 

aluminum components so they could be moved elsewhere if needed. They were built by J. A. Tiberti 

Construction Company of Las Vegas.

ATTACHMENT B

NUCLEAR ROCKET AND RAMJET ENGINE TESTS

Page 1 of 15
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 63 of 97

Maintenance Assembly and Disassembly Building – This massive concrete structure has 30,000 

ft2 of floor area where work was performed assembling and disassembling reactors and their 

components before and after tests. A small office and warehouse building and a guard station are 

Figure B-1. Details of nuclear propulsion sites. 

ATTACHMENT B

NUCLEAR ROCKET AND RAMJET ENGINE TESTS

Page 2 of 15
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 64 of 97

Figure B-2. Nuclear Rocket Development Station (LANL 1986).

nearby. Sierra Construction Company, Inc. of Las Vegas was the contractor for the building. J. A. 

Tiberti Construction was contractor for a hot cell addition. 

Test Cell Area – The Test Cell (A and C, later ETS-1) was constructed of reinforced concrete with a 

floor area of 1,680 ft2

. Reactors and reactor systems to be tested were housed in the cell but were 

mounted on a railcar backed up to the cell. The reactor was connected to receiving instruments 

inside the Test Cell that transmitted needed information to recording instruments in the Control 

building about 2 mi away. The railcar bearing the reactor was moved by a remotely controlled 

locomotive over a rail line to and from the MAD building. In addition, there were water storage and 

other facilities constructed in the Test Cell area. The contractor for the Test Cell and tank farm was 

the Petroleum Combustion and Engineering Company of Los Angeles. Pittsburgh-Des Moines Steel 

Company of El Monte, California, was the contractor for the water storage tanks.

Other contractors were as follows:

1. Mercury-Jackass Flats access road, Fred Galante and L. B. Wells of Visalia, California.

2. Water supply wells, Perry Brothers Drilling Company, Flagstaff, Arizona.

3. Roads within the area, J. L. Croft and Sons, Inc., Saugus, California.

4. Water distribution system, Hansen Plumbing and Heating Company, San Bernardino, 

California.

ATTACHMENT B

NUCLEAR ROCKET AND RAMJET ENGINE TESTS

Page 3 of 15
Document No. ORAUT-TKBS-0008-2 Revision No. 01 Effective Date: 10/01/2007 Page 65 of 97

5. Railroad facilities, A. D. Schader Company, San Francisco, California.

6. Technical Services building, J. A. Tiberti Construction Company, Las Vegas, Nevada.

7. Road H, J. L. Croft and Sons, Saugus, California.

B.3 ROVER

In 1955, the United States embarked on a program to develop a nuclear rocket engine under joint 

sponsorship of the U.S. Air Force and AEC. The program known as Project ROVER was initiated at 

LASL. LASL was responsible for developing reactor technology for the Project ROVER nuclear rocket 

engine based on the concept of a solid hydrogen-cooled core in which the existing gas expanded 

through a rocket nozzle and discharged into space. The motivation for the development of such a 

nuclear rocket engine was that it could provide about twice the specific impulse (thrust) of the best 

chemical rockets corresponding to a reduction of a factor of five in the ratio of take-off mass to final 

mass at Earth escape velocity. Approximately 120 of the LASL staff worked full time on Project 

ROVER.

The U.S. Air Force was responsible for the non-nuclear portion of the project. The other key players 

were the Aerojet-General Corporation, the prime contractor to develop the complete rocket engine 

system, and the Astronuclear Laboratory of the Westinghouse Electric Corporation, the principal 

subcontractor to LASL, which was given the role of establishing a basic reactor design and of leading 

the effort to develop nuclear fuels for the project.

The engine development test program was part of the technology demonstration. Its objectives were 

to test non-nuclear system components, determine system characteristics during start-up, full-power, 

and shut-down conditions, evaluate control concepts, and qualify the engine test-stand operations in a 

downward-firing configuration with simulated altitude and space conditions. These objectives were 

met or exceeded in the NERVA Reactor Experiment (NRX)/Engine Systems Test (EST) and 

Experimental Engine (XE) programs. XE, a prototype flight engine system, which consisted of a 

flight-type reactor with non-nuclear flight components, was tested in a simulated space environment, 

over some 28 starts and restarts. Figure B-3 shows the chronology of ROVER Program tests. 

Figures B-4 and B-5 are schematic representations of the reactors for ground-based systems tests 

and nuclear rocket engine configurations, respectively.

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Figure B-3. Chronology of major nuclear rocket tests (LANL 1986).

Figure B-4. Reactors for ground-based systems tests (NASA 1991).
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Figure B-5. Nuclear rocket engine configurations

(NASA 1991).

In 1960, the AEC and NASA formed the Space Nuclear Propulsion Office (later the Space Nuclear 

Systems Office) to administer the NERVA program to develop an operational nuclear rocket engine. 

Such a nuclear-powered rocket was visualized for use in space travel, given that the crew could be 

adequately protected from radiation produced by the engine. The ROVER program consisted of the 

NRX and EST programs; the Research Reactor tests program consisted of the KIWI, PHOEBUS, 

PEWEE, and the Nuclear Furnace tests.

B.3.1

A series of reactor and engine tests were conducted in the 400 Area of NTS where major testing 

facilities were built for the ROVER program (Figure B-1). These included an assembly and 

disassembly facility and two testing facilities for the research and engine reactors. The test series 

was initiated with a family of research reactors named KIWI (for the flightless bird of New Zealand). 

The program objectives were first to demonstrate the proof of principle, then to establish the basic 

reactor technology and to develop defensible design concepts. These reactors were the first to 

demonstrate the use of high-temperature fuels and to operate with liquid hydrogen. These tests led to 

the NRX series of developmental reactors from 1964 to 1969.

Project Reactor and Engine Tests

KIWI Reactor Tests

July 1, 1959: The first reactor test, KIWI-A, was conducted successfully at the Nevada Test Site. 

The reactor operated for 5 min at 70 MW and provided important design and materials 

information. The fuel was hot enough (2,683°K) to melt carbide fuel particles. Vibrations in the 

core produced structural damage in the graphite elements. The reactor employed uncoated, 

UO2-loaded, plate-type fuel elements and was cooled with gaseous hydrogen.

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July 8, 1960: KIWI-A PRIME was tested for nearly 6 min at 85 MW to demonstrate an improved 

fuel element design. The reactor used short, cylindrical, UO2-loaded fuel elements in graphite 

modules.

October 10, 1960: KIWI-A3 reactor operated in excess of 5 min at 100 MW. The fuel was similar 

to that used in the previous test. This experiment was the third and last in the KIWI-A series of 

proof-of-principal tests conducted by LASL.

December 7, 1961: KIWI-B1A reactor, first of a new series, was tested by LASL. KIWI-B 

reactors were designed for 1,100 MW and used reflector control and a regeneratively cooled 

nozzle. This test was the last to be run with gaseous hydrogen coolant. After 30 s, a hydrogen 

leak in the nozzle and the pressure vessel interface forced termination of the run. However, the 

planned maximum power of 300 MW was achieved. The core consisted of cylindrical UO2-loaded 

fuel elements.

September 1, 1962: KIWI-B1B reactor test was the first to operate with liquid hydrogen. The test 

met its primary objective of demonstrating the ability of the system to start up and run using liquid 

hydrogen. Following a smooth, stable start, the run was terminated after a few seconds at 

900 MW when portions of several fuel elements were ejected from the reactor.

November 30, 1962: KIWI-B4A, the first design intended as a prototype flight reactor, was tested. 

The power run was terminated at about the 50% level when bright flashes in the exhaust (caused 

by ejection of core material) occurred with increasing frequency. The core consisted for the first 

time of full-length, 19-hole, hexagonal fuel elements loaded with UO2. 

In 1963-1964, several cold-flow tests of KIWI-B-type reactors were carried out to determine the 

solutions for the severe structural damage observed in the previous tests. These tests were 

performed with gaseous nitrogen, helium, and hydrogen, and they demonstrated that the structural 

core damage was due to flow-induced vibrations. Based on results of these tests and analyses, 

design changes were successful in eliminating vibrations.

May 13, 1964: KIWI-B4D, the first test at full design power, was carried out with no indication of 

core vibration. This was also the first time a completely automatic start was accomplished for a 

nuclear rocket reactor. The test was terminated after 60 s at full power when several nozzle tubes 

ruptured. 

August 28, 1964: KIWI-B4E, the eighth and final KIWI reactor, was tested by LASL. The reactor 

operated for more than 12 min, of which 8 min were at nearly full power. The reactor operation 

was smooth and stable. On September 10, the reactor was restarted and ran at nearly full power 

for 2.5 min. This was the first demonstration of the KIWI reactor’s ability to restart.

January 12, 1965: The KIWI-Transient Nuclear Test reactor test was successfully completed by 

LASL. In this flight safety test, a KIWI-B-Type reactor was deliberately destroyed by placing it on 

a fast excursion to confirm the analytical models of the reactor behavior during a power excursion.

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PHOEBUS Reactor Tests

June 1965: The aims of PHOEBUS-1A, the first test of a new class of reactors, were to increase 

the specific impulse, the power density in the core, and the power level. On June 25, 1965, the 

test was run successfully at full power (1,090 MW) and core exit temperature (2,370°K) for 

10.5 min. The reactor was subsequently damaged when the facility’s liquid hydrogen supply was 

exhausted. The event was not the result of a reactor defect.

February 23, 1967: PHOEBUS-1B operated for 45 min of which 30 min were at the design power 

level of 1,500 MW. The primary purpose of the test was to determine how the higher power 

operation affected the reactor. This fuel was the same as that used in PHOEBUS 1-A.

June 26, 1968: PHOEBUS-2A, the most powerful nuclear rocket reactor ever built, ran for 

12.5 min above 4,000 MW. The duration of the test was determined by the available coolant 

supply. Designed for 5,000 MW, the test was limited to 80% of full power because the aluminum 

segments of the pressure vessel clamp band overheated prematurely.

PEWEE Reactor Test

December 4, 1968: PEWEE reactor testing was successfully completed. PEWEE, designed to 

be a small test-bed reactor, set records in power density and temperature by operating at 503 MW 

for 40 min at a coolant exit temperature of 2550°K and a core average power density of 

2,340 MW/m3

. This power density was 50% greater than that required for the 1,500-MW NERVA 

reactor. The core contained the same type of fuel elements as PHOEBUS-1A. 

Nuclear Furnace Test (NF-1)

June 1, 1972: NF-1 was successfully accomplished in Test Cell C at the NRDS. The reactor

operated for 109 min at the full design power of 44 MW, which demonstrated fuel performance at 

a coolant exit temperature up to 2,500°K and a near-record peak power density in the fuel. Seven 

reactor runs were conducted with the longest test running nearly 2 hr at design power on July 27, 

1972. NF-1 was designed with a remotely replaceable core in a reusable test bed and was 

intended as an inexpensive approach to multiple testing of advanced fuel materials and structures. 

Another special feature of this test series was evaluation of a reactor effluent clean-up system. 

The system performed as expected in removing radioactive contaminants from the effluent reactor 

gas. Two types of fuel elements, (UC-ZrC)C composite fuel and the pure (U, Zr)C carbide fuel, 

were tested in NF-1.

The Nuclear Furnace (NF-1) core was replaceable and the test bed reusable, which was unique to 

the NF-1 program. The NRDS had facilities designed for replacement of the core materials in 

NF-1. During operation, the nuclear furnace was well shielded, operated from a remote location, 

and observed by closed-circuit television. This essentially eliminated the potential for external 

exposure of personnel during the test runs. However, the maintenance performed between runs 

required hands-on manipulation that could have resulted in significant exposure to the photon 

fields from fresh, and in many cases decayed, fission products.

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NERVA NRX Reactor Tests

September 24, 1964: The NRX-A2 reactor was the first NERVA reactor tested at full power by 

Westinghouse. The reactor operated in the range of half to full power (1,100 MW) for about 6 min, 

the time limited by the available hydrogen gas supply. The test was successful and demonstrated 

an equivalent specific impulse of 760 s in vacuum.

April 23, 1965: The NRX-A3 reactor operated for about 8 min with about 3.5 min at full power. 

The test was terminated by a spurious trip from the turbine overspeed circuit. The reactor was 

restarted on May 20 and operated at full power for over 13 min. It was started again on May 28 

and operated for 45 min in the low-to-medium-power range to explore the limits of the operating 

map. The total operating time was 65 min with over 16.6 min at full power.

February 3 to March 25.1966: The NRX/EST, the first NERVA breadboard power plant, was 

operated during 5 different days for a total of 1 hr and 50 min, of which 28 min were at full power 

(1,100 to 1,200 MW). These times were by far the greatest achieved by a single nuclear rocket 

reactor as of this date.

June 8, 1966: NRX-A5 reactor operated successfully at full power for 15.5 min. It was restarted 

and operated again at full power (1,100 MW) on June 23 for 14.5 min to bring the total operating 

time at full power to 0.5 hr. 

December 15, 1967: The NRX-A6 reactor test exceeded the NERVA design goal of 60 min at 

1,100 MW in a single run.

XE PRIME Test

March 1968: The XE PRIME test, the first down-firing prototype nuclear rocket engine, 

successfully operated at 1,100 MW. The reactor operated at various power levels for a total of 

115 min that included 28 restarts. This test series was a significant milestone in the nuclear rocket 

program and demonstrated the feasibility of the NERVA concept. In this year, the production of 

the Saturn V chemical rocket was suspended. It would have been the prime launch vehicle for 

NERVA.

January 1973: The ROVER nuclear rocket program was terminated. It was judged a technical 

success, but changing national priorities resulted in the decision to cancel the program.

B.4 PLUTO

In 1957, LRL began the PLUTO program to develop a nuclear ramjet engine (AEC 1972). Two tests 

were conducted in Area 401 of the TORY II-A reactor on May 14, 1960, and the TORY II-C reactor on 

May 16, 1964. As the reactor design was for an air-breathing engine, high-pressure air (about 3,800 

psi) from onsite storage tanks was passed through the core for cooling during the tests.

B.4.1

The main facilities in the 401 Area (Figure B-1) were:

Area 401 Major Facilities

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1. Critical Assembly Building of approximately 4,000 ft2

, steel frame and aluminum siding.

2. Control Building with 2,900 ft2 of floor area, steel and aluminum construction.

3. Assembly and shop building with 2,900 ft2 of floor, steel and aluminum construction.

4. Disassembly Building constructed of concrete where shielding was required and concrete 

block elsewhere. This facility, with an area of 16,100 ft2

, was used for the disassembly of hot 

reactors following tests.

5. Check Station and Emergency Shelter, total area about 2,000 ft2

, concrete block construction. 

The emergency shelter was a partially-buried Quonset building.

6. Railroad - Two mi of railroad connecting the Disassembly Building with the test bunker.

7. Inter-plant roads, approximately 2 mi long. 

8. Tank Farm (High-Pressure Air Storage), Rupert Plumbing.

Project Pluto buildings included a Control Room (Building 2101), Assembly Building (2102), Data 

Reduction Building (2107), Hot Critical Facility (2103), and the Check Station (2105). The testing area 

included the Test Bunker (2203), the Disassembly Building (2201) and the Railcar Washdown (2202). 

The Disassembly Building was constructed in 1959-60. It was used from 1961 to 1964 during Project 

PLUTO to decontaminate the Tory II-A and Tory II-C reactors. Significant quantities of radioactive 

material were produced during the Tory reactor testing program, some of which was disposed in the 

disassembly area radioactive leachfield. Building 2201 was used again in 1972 to repackage PLUTO 

solid fuel elements for shipment from Area 26 (DOE 2002c).

B.4.2

The TORY II-A and TORY II-C reactors were mounted on a special railroad flat car (Figure B-6) that

could be moved after operation into a shielded inspection and disassembly facility. This test vehicle 

assembly was 44 ft long, 14.5 ft wide and 12 ft high. The reactor and duct system, as well as the 

railcar, each weighed about 20 tons for a total of 40 tons. Because the PLUTO reactor concept 

involved the use of an air-breathing engine, high-pressure air from storage tanks was passed through 

the core for cooling. The duct system consisted of five flanged cylindrical sections and a nozzle 

bolted together and mounted on the flat car. One duct contained the reactor core and the others 

contained control systems. The reactor duct was 57 in. in diameter and 103 in. long and weighed 

over 9 tons.

TORY Reactor Tests

The TORY II-A and II-C cores consisted of homogenous beryllia and uranium oxide extruded into 

hollow hexagonal rods about the diameter of a pencil and 4 in. long. There were a total of 464,595 

rods of which 293,328 were fueled with 63.5 kg of 93% enriched uranium. This bundle was held 

together by 32 bards of peripheral springs that exerted compressive force radially and 121 tie rods 

with compression springs that exerted compressive force axially. Eighteen of these rods contained 

hafnium control rods.

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The TORY II-A reactor was designed with two graphite shells that clamped around the outside of the 

reactor; deuterium was passed through the core for moderation to sustain criticality. The graphite 

shell around the outside of the reactor could be retracted and the deuterium flow terminated to control 

reactor power. Control rods were also available to remotely control reactor power.

Figure B-6. Schematic diagram of TORY II-C reactor on vehicle flatcar. 

The PLUTO Project reactor concept envisioned reactor-powered aircraft that would be restricted to 

flights at relatively low altitudes. During the two PLUTO Project tests, the reactor sloughed off the fuel 

and debris as high-pressure air was passed through the reactor core at very high velocity. This would 

spread significant amounts of radioactive debris in its path of travel and potentially cause health 

hazards from exposure to the radioactive contamination.

During the test of TORY II-A, a visible cloud was emitted from the reactor that extended north into the 

forward area past CP-2. Most of the radioactive particles fell within about 1 mi downwind of the 

reactor, but the noble gases and tritium were contained in a cloud carried in a northerly direction. 

Based on downwind sampling, no radioactivity was released off the site.

The TORY II-C test was the second and last test performed under the PLUTO Program. The reactor 

fuel had the same configuration as TORY II-A and used high-pressure air for core cooling. Again, the 

core sloughed off particulates and gaseous materials during the run that produced a visible cloud that 

moved northward over the CP-2 complex. Like the Tory II-A test, the particulates fell out within about 

1 mi of the reactor, while the gaseous materials continued northward. Downwind sampling did not 

detect any release activity off the site.

Radiation readings on the reactor surfaces were reported as being above 1,000 R (Shockley 2005). 

Pocket ion chambers (PICs) were used when reentries were made. Two PICs were used for each 

worker and were compared for dose determination. Following the test runs, the reactor was moved 

remotely from the test stand for storage and inspection using the railroad system to a shielded vault 

with a 5-ft-diameter opening. This vault had 4-ft-thick walls for shielding. Entries were made under 

the control of REECo Rad Safe Monitors and LRL health physicists along with a very small contingent 

of the PLUTO technical staff.

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The PLUTO project was terminated after TORY II-C for study and partial dismantling. There were no 

additional tests under the PLUTO Project during 1970 and 1971. The overall Nuclear Rocket Engine 

Test series was discontinued after 1971.

B.5 Summary of Radiological Hazards

The hazards associated with the nuclear rocket and ramjet engine tests relate to the operation of test 

reactors. Mobile radiation survey teams entered the area at a designated time after a test run to 

collect measurements that would define the isodose rate contours. Maps were prepared and posted 

at the control points. Reentry and stay times varied and were calculated so that personnel radiation 

exposure limits could be met. Radiation monitors accompanied each group of personnel entering the 

radiation area to monitor and provide information regarding radiation levels at work locations. 

Radiation measurements were obtained at station, equipment, and structure location and published in 

the on-site radiological safety reports that were prepared for each test.

B.5.1

External exposures were primarily due to the decay of fission products. The reactors were operated 

remotely. Because of the distance between the operating reactors and personnel, external exposures 

during tests were, at most, a few millirem. Following the tests, the reactors were returned to heavily 

shielded cells by rail. Usually several hours to several days elapsed between reactor operation and 

the need for personnel to enter the cells for maintenance. However, even then the dose rates could 

have been several roentgen per hour. This required that the work be performed very rapidly with 

short residence times, often as little as 30 s. There were also exposures to H-8 plume-tracking 

teams, although they were generally less than those for hands-on work with the reactors.

External Exposure

Conventional dosimetry was used for monitoring the external fields and exposures. These included 

the survey instruments and film dosimeters employed by REECo, LASL, and LRL at that time. 

Standard film dosimeters and PICs were used for personnel monitoring. Section 6 of the NTS site 

profile contains more detail on the external dosimetry used at the NTS.

B.5.2

The primary source of internal exposure was the fission products released during reactor operation. 

Table B-1 lists the radionuclides identified in the effluent clouds during reactor operation (DOE 

1995a). Several of the tests released radioactive effluent of sufficient magnitude that it could be 

detected off the site (DOE 1995a). Table B-2 summarizes these releases. 

Internal Exposure

B.6 Onsite Radiological Support for Reactor Tests

The REECo Rad-Safe Division had three objectives in providing support for reactor tests (REECo 

1961a):

• Radiological safety support on the NTS in accordance with the NTS standard operating 

procedure (SOP) as outlined in detail in the REECo Rad-Safe Division's SOP Manual (REECo 

1961b). This support includes monitoring and sampling at all NTS work locations.

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• Low-level radiation monitoring, sampling, and analyses within a 10-mi radius of each reactor 

site excluding the user-controlled area. This data is obtained for dissemination to the user 

Table B-1. Radionuclides found in effluent clouds from nuclear rocket and ramjet engine tests (DOE 

1995a).

Radionuclide Half life Radionuclide Half life Radionuclide Half life

Ni-57 35.6 hr Ru-103 39.6 d Xe-135 9 hr

Kr-85m 4.5 hr Ru-105 4.4 hr Cs, Ba-137 30.1 yra

Kr-87 76 min Ru, Rh-106 369 da Cs-138 32 min

Kr-88 2.8 hr Te-129 70 min Ba-239 1.4 hr

Sr, Y-89 50.5 da Te-131 24 min Ba, La-140 13 da

Sr, Y-90 29 yra 1-131 8 d Ce-141 32 d

Sr-91 9.5 hr Te-132 3.25 d La-142 1.5 hr

Sr-92 2.7 hr 1-132 2.3 hr Ce-143 34 hr

Yr-93 10 hr Te-133m 55 min Ce-144 284.4 d

Zr-95 64 d I-133 21 hr Nd-147 11 d

Nb-95 3.5 d Xe-133 5.2 d U-234 244,000 yr

Zr-97 17 hr I-134 53 min Np-249 2.3 d

Mo-99 2.75 d I-135 6.6 hr

group, the U.S. Weather Bureau, the U.S. Public Health Service, and other interested 

agencies.

• Monitoring and sampling within the user-controlled area as requested.

Gamma radiation iso-dose rate contours of 0.1, 1, 10, 100, and 1,000 mR/hr were determined with 

portable hand-carried instruments held approximately 3 ft above surface level. Measurements were 

referenced .to stakes and fallout tray holders beyond the arc roads on existing trails and roads. The 

initial surveys were performed as soon as possible after initial fallout deposition and were followed by 

a resurvey in approximately 8 hr. Subsequent surveys were performed to determine the 1, 10, 100, 

and 1,000 mR/hr iso-dose rate contours at intervals timed to provide evenly spaced points on the 

projected decay curve. The instruments used were:

• Precision Model 111 (scintillation) instruments with six ranges between 0 and 5 mR/hr and 

calibrated at 12 points with a 60Co source.

• Low-range beta-gamma instruments calibrated at 2 points on each range with a 60Co source.

• Ion chamber instruments with five ranges between 0 and 50 R/hr calibrated at 12 points with a 

60Co source.

Radioactive fallout was collected on adhesive surface trays. The trays were positioned on stakes 

surrounding the test cell at approximately 5- and 10-mi radii. The fallout trays were supplemented by 

collectors placed on existing lateral and radial roads at distances between 5 and 10 mi from the test 

cell. Fallout trays that showed a beta activity of more than 5 x 10-2 μCi/m2 were assayed for alpha 

activity using a thin-window gas-flow proportional counter. This method could detect alpha at 

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9 x 10-6 μCi/m2 with an error of ±3 x 10-6 μCi/m2 at a 90% confidence level. Fallout trays were 

collected as soon as possible after initial effluent deposition, and sent to the REECo Rad-Chem 

Laboratory where they were assayed for beta activity with a large area, thin-window (0.85 mg/cm2

) 

gas-flow proportional counter. Additional fallout trays were collected on D + 1 and assayed in the 

Table B-2. Summary of tests of nuclear-powered rocket and ramjet 

engines which generated radioactive effluent detected off the site

(DOE 1995a).

Test name Date

Time of day

(PST)

Integrated power

(MW-s)

Release

curiesa 

KIWI A 07/01/59 0900-0905 21,000 840

KIWI A PRIME 07/08/60 60,000 2,500

KIWI A-3 10/19/60 60,000 2,500

TORY II-A 10/06/61 1254 31,300 635

KIWI B-IA 12/07/61 1415-1417 30,000 1,300

KIWI B-1B 09/01/62 1130 10,000 420

KIWI B-4A 11/30/62 1207 40,000 1,700

TORY II-C 05/12/64 1215 256

KIWI B-4D 05/13/64 0945 110,000 4,600

TORY II-C 05/20/64 1250 741

KIWI B-4E 08/28/64 1139-1147 500,000 21,000

KIWI B-4E 09/10/64 1055-1057 180,000 7,600

NRX-A2 09/24/64 0955-1005 300,000 1,100

NRX-A2 10/15/64 1110-1130 300,000 11100

KIWI 01/12/65 1058 9,000 15,000

NRX-A3 04/23/65 1254-1258 320,000 530

NRX-A3 05/20/65 0932-0946 840,000 2,400

NRX-A3 05/28/65 0930-1000 500,000 1,200

PHOEBUS 1A 06/25/65 1215-1226 740,000 22,000

NRX-A4/EST 02/03/66 1116-11233 390,000 12

NRX-A4/EST 03/03/66 1310-13163 880,000 100

NRX-A4/EST 03/16/66 1004-1020 1,000,000 27,000

NRX-A4/EST 03/25/66 0933.0948 1,100,000 28,000

NRX-A5 06/08/66 1302-1318 1,200,000 1,200

NRX-A5 06/23/66 0935-0950 1,000,000 80,000

PHOEBUS 1B 02/10/67 1130 140,000 34,000

PHOEBUS 1B 02/23/67 1400-1430 2,600,000 240,000

NRX-A6 12/15/67 1059-1159 4,500,000 53,000

PHOEBUS 2A 06/08/68 1014-1025 643,000 7,100

PHOEBUS 2A 06/26/68 1137-1209 4,500,000 51,000

PHOEBUS 2A 07/18/68 1210-1222 660,000 2,100

PHOEBUS 2A 07/18/68 1350-1408 2,000,000

PEWEE 1 12/04/68 1332-1435 1,530,000 230,000

XE PRIME 06/11/69 0942-0953 425,000 820

XE PRIME 08/28/69 1518-1551 338,000 530

a. As calculated for 12 hr after the time of release (R+12 hr). Short-lived 

radionuclides have decayed to stable forms by this time.

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same manner. This assay method was capable of detecting beta activity at 9 x 10-5 μCi/m2 with error 

limits of ±3 x 10-5 μCi/m2 at a confidence level of 90%. The fallout trays collected on the 5- and 10-mi 

perimeters were agglomerated according to distance, and a gamma spectrum was obtained with a 4- 

by 4-in. NaI crystal.

Intensity, decay rates, and time of arrival of the effluent cloud with radiation levels above 0.3 mR/hr 

were determined from telemetered data from Geiger-Muller detectors. The detectors were at the Area 

12 Mesa, Area 12 Camp, Security Station 700, BJY, CP-2, Sugar Bunker, Well 5, and Camp Mercury.

Arrival times of the fallout cloud at two locations within a 10-mi radius from the test reactors were 

determined with Staplex air samplers using 4-in.-diameter glass fiber prefilters followed by 

4-in.-diameter by 1-in.-thick charcoal cartridges. As soon as the fallout was deposited, all filters were 

sent to the Rad-Chem Laboratory for analysis. Arrival times on the 5 and 10 mi area was determined 

by vehicle-borne monitors using low-range Geiger-Muller and scintillation instruments. Staplex air 

samplers were operated at Area 12 Mesa, Area 12 Camp, Security Station 700, Yucca Flats, (BJY), 

CP-2, Frenchman Flat (well 5), Mercury, and at the ROVER and PLUTO administration areas. Filters 

were collected after possible fallout deposition, and then on a daily basis for several days following 

each major reactor test.

Particle size samples were obtained at approximately 5 and 10 mi from the reactor during the fallout 

period by vehicle-borne monitors operating portable generator-powered five-stage cascade impactors.

The gamma activity pattern from cloud passage and fallout was determined with film badges 

positioned approximately 1 ft above the ground at each fallout tray location and protected from the 

heat by a reflective cover as well as with trailer mounted air-samplers and hand-held instruments.

The REECo Rad-Chem Laboratory was used to assay all collected samples. Special techniques 

were used to discount natural emitter activities.

Charcoal cartridges were assayed with gamma scintillation detectors using the 131I - 0.36 MeV 

photopeak. Because the spectra were often dominated by contribution of other nuclides (133I, 135I, 

etc.) spectrum-stripping was frequently required at early times to quantify the 131I. The sensitivity of 

this technique was such that a 5 x 10-5 μCi/sample could be detected with an error of ±1.4 x 10-5 μCi 

at a 90% confidence level. 

Selected air samples and fallout trays were analyzed for specific fission products such as 89Sr, 90Sr, 

137Cs, 95Zr, and 95Nb.

Special monitoring instruments attached to criticality alarms were used to detect possible inadvertent 

critical assembly of fissionable material, if requested. Trained emergency radiation monitoring 

personnel were standing by for emergency support.

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TABLE OF CONTENTS

SECTION TITLE

C.1 REECo......................................................................................................................................

PAGE

77

C.2 Other Contractors (EG&G Energy Measurements, H&N, and RSN) ........................................78

C.3 Current and Former NTS Contractors.......................................................................................78

C.4 Job Title References .................................................................................................................78

C.1 REECo

REECo job titles that probably

REECo job titles that 

had some potential for workplace external or internal exposures (Table 

C-1) include field workers participating in post-event activities (i.e., drill backs and mine backs) or 

workers who directly handled radiological materials (laboratory analysis, sample collection, and

workers assigned to areas that had the potential to be radiologically controlled or contaminated). 

These workers generally had Q clearances and were RadWorker-II trained, which included the 

qualification to wear a respirator and don anticontamination (Anti-C) clothing. Supervisors of field 

personnel are generally included because they are by definition backups for their personnel. Some 

select managers are also included for the same reason.

possibly had some potential for workplace external or internal exposures (Table 

C-2) include field workers who could have worked underground, on drill rigs, in downhole shafts, or

have entered radiologically controlled or contaminated areas during the performance of their tasks. 

The positions could

The column descriptions for Tables C-1 and C-2 for REECo job titles are:

have required the worker to qualify for a respirator and don Anti-C clothing (i.e., 

be RadWorker-II trained) depending on the job assignment. Based on the position description, these 

workers could have worked underground in tunnels or at downhole shaft sites, performed emergency 

response duties, or had other indications of potential entry into contaminated areas (e.g., respirator 

use or Anti-C requirements). Managers and supervisors of field personnel are generally included 

because they are by definition backups for their personnel. Other REECo job titles were 

administrative, support service (janitorial, cafeteria), or clerical in nature with no access to or 

assignment in radiological areas. These workers did not have similar exposure potential and are not 

listed in the tables. 

• DAILY TUNNEL WORKER INCLUDING REENTRY & MINE BACK SUPPORT– Workers and 

support personnel assigned work underground. 

• OCCASIONAL TUNNEL WORK POSSIBLE – Workers with the potential to work underground 

who were assigned as needed. 

• DAILY DRILL CREW INCLUDING DRILL-BACK SUPPORT- Workers and support personnel 

assigned to drilling operations. 

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• OCCASIONAL DRILL RIG/DOWNHOLE WORK POSSIBLE - Workers with the potential to 

work on a drill rig or at a downhole (vertical shaft) site who were assigned as needed. 

• LAB WORKER/FIELD SAMPLER

• NEUTRON EXPOSURE POTENTIAL

• FIELD WORK WITH POTENTIAL FOR RADIOLOGICAL EXPOSURE – This category is 

included because some position descriptions list “radiological hazard” with no other 

descriptors.

• EMERGENCY RESPONSE/MINE RESCUE TEAM

• RESPIRATOR QUALIFICATION REQUIRED

• ANTI-C CLOTHING USE

• Q CLEARANCE REQUIRED

C.2 Other Contractors (EG&G Energy Measurements, H&N, and RSN)

Position descriptions were supplied for these contractors. Table C-3 lists job titles that could have 

had the potential for exposure to radionuclides. The potential for neutron exposure is specifically 

noted in the table. There were additional contractors, but no position descriptions are available for 

these contractors. 

C.3 Current and Former NTS Contractors

NSTec currently manages and operates the test site and its related facilities for the Nevada Site 

Office. Wackenhut Services (WSI) continues to provide security services at NTS. Previous major 

contractors for the NTS included the team of Bechtel Nevada (BN) Corporation (1995-2007), REECo 

(1953-1995), Holmes & Narver, (H&N) (1956-1990), Fenix & Sisson of Nevada (FSN) (1963-1990), 

and Edgerton, Germeshausen, and Grier (EG&G) Corporation (1951-1995).

C.4 Job Title References

1. REECo Job Title Indices and Position Descriptions (dated 1992 to 1993 for crafts, 1989 to 

1994 for exempts, 1983 to 1993 for technical, and 1995 for nonexempts).

2. EG&G Job Title Index and Position Descriptions (various dates from 1976 to 1992).

3. H&N Position Descriptions (various dates from 1975 to 1982).

4. RSN Position Descriptions (various dates from 1976 to 1992).

ATTACHMENT C

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Table C-1. REECo job titles that probably had some potential for workplace external and/or internal exposures. Tunnel work Downhole work Lab Neutrons Other field work Qualifications

Job title

Job 

category

Daily tunnel 

worker 

including 

reentry & mine 

back support

Occasional 

tunnel work 

possible (as 

needed)

Daily 

drill crew 

including 

drill-back 

support

Occasional 

drill rig/ 

downhole 

work 

possible (as 

needed)

Lab 

worker/

field 

sampler

Neutron 

exposure 

potentialc

Field work 

w/potential 

for radiological 

exposure

Emergency 

response/ 

mine 

rescue 

team

Respirator 

qualification 

required

Anticontamination 

clothing 

use

Q 

clearance 

required

Bull Gang Foreman

Bull Gang Worker Craft x x x x x

b xb

Calibration Lab Supervisor Exempt x x x

b xb xb

Chemist I - IV

Sr. Chemist

Principal Chemist

Analytical Chemistry Section Chief

Exempt x x x

b xb xb

Derrickman Craft x x x x

b xb

Dinkey Locomotive Operator

Swamper (signal man/load attendant) Craft x x x x

b xb

Dosimetry Supervisor Exempt x x x

b xb xb

Driller 

Drill Helper

Drilling Support Superintendent or Tool Pusher

Craft x x x x

b xb

Drilling Support Superintendent or Tool Pusher

Drill Rig Superintendent (drilling post shot support) Exempt x x x

b xb xb

Environmental Analyst Exempt x x x

b xb xb

Environmental Compliance Officer I-IV Exempt x x x x

b xb xb

ES&H Technical Trainee Nonexempt x

Health Physicist I-IV

Sr. Health Physicist

Principal Health Physicist

Exempt x

a x xa x x x x xb xb xb

Health Protection Technician I-IV Technical x x x x x x

b x

Industrial Hygienist I-IV

Sr. Industrial Hygienist

Principal Industrial Hygienist

Industrial Hygienist Field Ops Section Chief

Exempt x

a x xa x x x xb xb xb

Lab Technician I-IV Technical x x x x x x x

Lab Technician Trainee Nonexempt x x x x

b x

Miner

Miner-Welder Craft x x x x x

b xb

Motorman-Oilfield Craft x x x x

b xb

Mucking Machine Operator Craft x x x x

b xb

Nonradioactive Waste Disposal Section Chief Exempt x x

b

Operations Superintendent (event work) Exempt x x x x x

b xb xb

Pipefitter/Plumber-Welder Craft x

a x x xb xb xb

Quality Control Technician I & II-Physical 

Standards & Calibration Lab

Sr. Quality Control Technician-Physical Standards 

& Calibration Lab

Technical x x x 

Quality Control Technician I & II-Cable Ops

Sr. Quality Control Technician-Cable Ops Technical x x x x x

b x 

Radioactive Waste Section Chief Exempt x x

b xb xb

Radioanalytical Section Chief Exempt x x x

b xb xb

Radiological Analysis Supervisor (Hot Lab work) Exempt x x x x x

b xb xb

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Tunnel work Downhole work Lab Neutrons Other field work Qualifications

Job title

Job 

category

Daily tunnel 

worker 

including 

reentry & mine 

back support

Occasional 

tunnel work 

possible (as 

needed)

Daily 

drill crew 

including 

drill-back 

support

Occasional 

drill rig/ 

downhole 

work 

possible (as 

needed)

Lab 

worker/

field 

sampler

Neutron 

exposure 

potentialc

Field work 

w/potential 

for radiological 

exposure

Emergency 

response/ 

mine 

rescue 

team

Respirator 

qualification 

required

Anticontamination 

clothing 

use

Q 

clearance 

required

Radiological Control Technician I-IV (Monitor) Technical x

a x xa x x x x x xb x

Radiological Engineering Technician Technical x x x x x

b

Radiological Field Operations Branch Chief

Radiological Field Operations Section Chief 

(Decon Facility Operations)

Exempt x x x x x x

b xb xb

Radiological Field Operations Supervisor (event 

support, reentry monitoring, hot line/base station 

operations for post shot drilling and tunneling)

Exempt x x x x x x x x

b xb xb

Radiological Instrument Technician I-IV Technical x x x x x

b

Respiratory Equipment Specialist

Respiratory Equipment Technician Technical x

a x x x x xb x 

Sample Management Section Chief Exempt x x 

Shifter Craft x x x x x

b xb

Tunnel Walker Exempt x x x x

b xb xb

Waste Control Section Chief Exempt x x

b xb xb

Waste Management Specialist I-IV

Sr. Waste Management Specialist

Principal Waste Management Specialist 

Waste Certification Specialist

Exempt x x x x

b xb xb

Waste Operations Special Projects Section Chief 

(Areas 3 & 5)

Waste Operations Technical Support Section Chief

Exempt x x

b xb xb

a. Not ALL workers with this job title were assigned to a tunnel or drilling operation, but they could have been.

b. These qualifications were not specifically stated in the position descriptions but were assumed based on duties.

c. Monitored with Neutron Track Emulsion, Type A film or TLD depending on the timeframe.

ATTACHMENT C

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Table C-2. REECo job titles that possibly

Job title

had some potential for workplace external and/or internal exposures.

Job 

category

Occasional 

tunnel work 

possible (as 

needed)

Occasional 

drill rig/ 

downhole 

work possible 

(as needed)

Field work w/ 

potential for 

radiological 

exposure

Emergency 

response/mine 

rescue team

Respirator 

qualification 

required

Anticontamination 

clothing use

Q 

clearance 

required

Carpenter

Carpenter Foreman

General Foreman

Carpenter Welder

Craft x x x x 

Combination Heavy-Duty Repairman/Welder

Combination Heavy-Duty Repairman/Welder Foreman

Combination Heavy-Duty Repairman/Welder General 

Foreman

Craft x x 

Compliance & Monitoring Section Chief (Occupational 

Safety) Exempt x x x 

Department ES&H Coordinator

Director, Emergency Management Office Exempt x x 

Ecologist Exempt x x x

Electronic Technician I-IV Technical x x x x

Engineering and Analysis Section Chief Exempt x x x

Engineering Intern Nonexempt x x x

Engineering Technician I & II Nonexempt x x x x

Environmental Compliance Officer Director

Environmental Program Section Chief

Environmental Remediation Section Chief

Environmental Restoration & Technology Develop Dept. 

Manager

Environmental Section Chief

Exempt x 

Environmental Compliance Officer I-IV Exempt x x x

Equipment Operator Craft x x

ER Superintendent

ESH&Q Division Manager Exempt x x 

Fire Captain

Fire Fighter Craft x x x x 

Fire Engineer Craft x x x

Fire Protection Services Section Chief Exempt x x

Forklift Operator Craft x x x

Grade Checker Craft x x

Heavy-Duty Repairman (Construction)-Equipment

Heavy-Duty Repairman Foreman

Heavy-Duty Repairman General Foreman

Craft x x 

Heavy-Duty Welder Craft x x x

High-Voltage Electrical Mechanic

High-Voltage Line Mechanic Craft x x x x 

Hoist Operator Craft x x x x

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Job title

Job 

category

Occasional 

tunnel work 

possible (as 

needed)

Occasional 

drill rig/ 

downhole 

work possible 

(as needed)

Field work w/ 

potential for 

radiological 

exposure

Emergency 

response/mine 

rescue team

Respirator 

qualification 

required

Anticontamination 

clothing use

Q 

clearance 

required

Industrial Control Wireman Craft x x x

Inventory Specialist Technical x x

IronworkerIronworker Foreman Craft x x

Ironworker General Foreman Craft x x x

Laborer Craft x x x

Laborer Foreman

Laborer General Foreman Craft x x 

Lineman Craft x x x x

Lineman Foreman

Lineman General Foreman Craft x x 

Locksmith Craft x x x x

Millwright

Millwright Foreman Craft x x x x 

Motor Patrol Operator Craft x x x

Occupational Safety & Fire Protection Dept. Manager Exempt x x x

Occupational Safety Professional I-III Exempt x x

Occupational Safety Specialist I-II Exempt x x

Painter

Painter Foreman Craft x x x x 

Paramedic Technical x x x x

Plumber/Refrigeration Mechanic Craft x x x x x x

Plumber/Refer Mechanic Foreman

Plumber/Refer Mechanic General Foreman Craft x x x x x 

Principal Ecologist

Principal Environmental Scientist Exempt x x x x 

Principal Occupational Safety Professional Exempt x x x x

Property Inspector Nonexempt x x x

Property Specialist Technical x x

Radiological Assessor 

Radiological Evaluation Section Chief Exempt x 

Sanitarian Technical x x

Scientific Intern Technical 

1983-1993 x x x 

Security Assistant Nonexempt x x x

Sheetmetal Foreman

Sheetmetal General Foreman

Sheetmetal Worker

Craft x x x x 

Sr. Ecologist

Sr. Environmental Compliance Officer Exempt x x x 

Waste Operations Dept. Manager Exempt x

Wireman

Wireman Foreman

Wireman General Foreman

Craft x x x x x 

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Table C-3. Other contractor job titles with some potential for 

workplace internal and/or external exposure. 

EG&G Energy Measurements, Inc.

1951-1995 

Neutron exposure 

potential?

Engineer x

Engineering Coordinator

Environmental Scientist

Exercise Planner

Health Physicist x

Industrial Hygienist x

Safety Administrator

Safety Assistant

Safety Engineer

Safety Specialist

Technician x

Raytheon Services Nevada (RSN)

1990-1995

Engineer x (well logging)

Geologist x (well logging)

Supervisor, Construction Services

Supervisor, Drilling x (well logging)

Supervisor, Field Operations

Supervisor, Field Operations

Supervisor, Material Testing Lab x

Technician x

Holmes & Narver (H&N), Inc.

1956-1990 

Chief, Materials Testing Lab x

Chief, Safety Programs

Engineer x (well logging)

Supervisor, Construction Services

Supervisor, Field Operations

Supervisor, Field Surveys

Supervisor, Material Testing x

ATTACHMENT C

NTS CONTRACTOR JOB TITLES AND EXPOSURE POTENTIAL REVIEW

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TABLE OF CONTENTS

SECTION TITLE

D.1 Post-Test Drilling Techniques ...................................................................................................

PAGE

84

D.2 Radioactivity Releases and Personnel Exposure .....................................................................89

D.3 Core Sampling ..........................................................................................................................92

D.4 Radioactivity Control Measures ................................................................................................92

D.5 Post-Test Radiation Monitoring ................................................................................................. 94

D.6 Exposed Workers......................................................................................................................96

D.1 Post-Test Drilling Techniques 

Following the detonation, the cavity cools and a collapse occurs that usually forms a subsidence 

crater (Figure D-1). Post-test drilling operations were often conducted as soon after detonation as 

possible to obtain information from the short-lived fission products. These operations were performed 

to obtain essential diagnostic data on the results of the underground tests (Johnson et al. 1966; Butler 

1984). Post-test drilling was used to obtain samples from the zone of interest for radiochemical 

analysis. In addition, it provided important information on cavity size, chimney dimensions, effects of 

the explosion on the surrounding material, and distribution of radioactivity in the test zone.

Three approaches to post-test drilling were used at NTS for both LLNL and LANL (Figure D-1): 

• Directional hole – A standard vertical drill rig was set up on undisturbed ground outside the 

collapsed area and the hole was started vertically. Directional drilling techniques 

(whipstocking) were then used to slant the borehole to the zone of interest.

• Angle hole – A special rig designed to drill on a slant (Hycalog 1 and 2 at LLNL and a similar 

drill rig at LANL) was set up on undisturbed ground outside the collapsed area, and the hole 

was drilled on a slant directly to the zone of interest.

• Vertical hole – A vertical rig was set up directly above the working point and the hole was 

drilled straight down to the zone of interest.

Method 3 was most commonly used at the NTS until late 1963. After that, Methods 1 and 2 were 

more commonly used by both LLNL and LANL. Cost and time studies showed that Method 1 was 

superior for holes 1,500 ft or deeper because of the greater speed with which round trips to remove 

the drill pipe (string) and replace the bits could be made. Method 2 was superior for shallower holes. 

The Hycalog drill rig used a similar angle-type drill rig for the post-test drilling program. Methods 1 

and 2 share the advantage over Method 3 that the drill rig was outside the collapsed zone. These rigs 

allowed preparations to be made before the test, which speeded up the post-test drilling. The 

Hycalog drill rig could be set up before the test, the surface casing set and spudded in, and other 

cellar preparations made. Then the drill rig could be quickly removed before test time depending on 

the expected motion intensity. After the test, the drill rig could be set up again quickly and the drilling 

could get under way with a minimum delay. LANL used the same process for Methods 1 and 2 in 

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Figure D-1. Three methods of post-test drilling

(Johnson et al. 1966). 

which the cellar could be prepared and the surface casing installed either before or after the test 

depending on the expected motion intensity.

At first, drilling was performed using drill rigs of the oil field type. The standard drill rig (Figures D-2 

and D-3) basically consists of the drilling platform with a small structure (dog house) to shelter the 

drillers at some distance from the drill pipe (string) entry point and a separate pipe-racking platform 

(known as the monkey board, Figure D-3, item 24) several feet above the drill platform. As the drilling 

progresses, one drilling laborer (roughneck) stood on the monkey board, and usually two stood on the 

platform to add new sections of pipe.

In rotary drilling, the hole is made by rotating a bit that chews or grinds its way through soil and rock. 

Because the turning force is usually applied by the drill rig, a rigid connection extending from the 

surface down to the bit is necessary. This rigid connection must be lengthened as the depth of the 

hole increases by adding drill pipe. These rigid connections are made using the derrick on the drill rig 

(Figure D-2). The derrick is a tall, strong structure, and its main function is to support the crown block, 

which holds all the weight of the drill pipe and associated equipment. 

When drilling angle holes (Method 2), LLNL used a Hycalog slant drilling rig (Figure D-4; Table D-1 

provides the Hycalog nomenclature for the numbered elements). The rigs were specially built for the 

DOE by Hycalog, Inc. of Shreveport, Louisiana. These rigs could drill at any angle between the 

vertical and 30 degrees off the vertical. The rig could therefore be set up some distance from the 

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Figure D-2. Schematic of a rotary drilling rig (Johnson et 

al. 1966).

surface above the detonation point at a distance safely beyond the anticipated range of surface 

collapse following the test (based on sampling depth). Most of the post-test holes at the NTS were 

drilled using the angle method after late 1964 because it decreased the drilling time.

In addition to the ability to drill on an angle, the Hycalog-type drill rig differed from the standard vertical 

rig in another very important way. A power swivel turned the drill pipe rather than a 

rotary-table-and-kelly arrangement. The swivel was driven by hydraulic power, and the drill pipe 

fastened directly to the swivel. Because the swivel drive allowed continuous drilling when the bit was 

being raised in the hole as well as when it was lowered, the problem of the drill pipe sticking in the 

hole was eliminated. This is a major advantage that the Hycalog-type rig has over the standard 

vertical rig. In addition, it improved the safety of the drilling operation.

A third advantage of the Hycalog was the ease of moving the rig on and off the preset casing before 

and after testing. This speeded up the post-test drilling process, and allowed cavity sampling to occur 

much sooner. LANL used a slant drill rig that was similar to the Hycalog rig, and it provided 

essentially the same benefits.

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Figure D-3. Schematic of a standard vertical test rig (Johnson et 

al. 1966).

REECo provided drilling support to both LLNL and LANL, so the drilling operations were very similar. 

The LLNL post-test drilling group provided the onsite representation for the Test Group Director and 

determined the drilling depths, the type of drill rig, and the location of the drill site in reference to the 

placement of the test and expected ground motion.

Las Alamos again used essentially the same process where the J-6 Event Engineer determined the 

location, placement of the drill rig, and the sampling depth. This then became the responsibility of the 

J-6 NTS engineer for oversight of these protocols (Eberhart 1993).

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Figure D-4. Hycalog drill rig. 

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Table D-1. Hycalog nomenclature. 

1 Electrical panel 28 Vacuum vent line

2 Fuel tank 29 Mud return line and valve

3 Derrick lay-down support 30 Sliding cellar doors

4 Main hydraulic reservoir 31 Derrick base

5 Main hydraulic pump 32 Drill pipe and trailer

6 Diesel engine 33 Pipe clamp hydraulic cylinder

7 Hydraulic motor 34 Pipe handler carriage

8 Oil cooler 35 Pipe handler frame

9 Transfer hydraulic pump 36 Cellar casing

10 Auxiliary hydraulic reservoir 37 Drill pipe

11 Derrick stiff leg 38 Backup tongs

12 90° angle drive 39 Pipe clamp

13 Derrick lift cylinder 40 Carriage travel hydraulic cylinder

14 Draw works 41 Pipe handler hydraulic cylinder

15 Derrick lay-down frame 42 Hydraulic-powered pipe breakout tongs

16 Auxiliary hydraulic pump 43 Power swivel assembly

17 Spider assembly, pipe slips 44 Power swivel hydraulic motors

18 Trailer support 45 Traveling blocks

19 Wheel guides 46 Cat line

20 Cellar containment cover 47 Drilling line

21 Rig stabilizer leg 48 Crown blocks

22 Drill string 49 Cat line boom

23 Rotating head 50 Secondary crown blocks

24 Blowout preventer 51 Sand line

25 Abandonment valve 52 Boom guy line

26 10-3/4-in. surface casing 53 Represents mud hose and hydraulic pressure return and drain lines

27 Applicable tools

D.2 Radioactivity Releases and Personnel Exposure

The drill bit must be cooled and lubricated to operate efficiently, the rigid connection between surface 

and bit is made up of sections of pipe (called joints) that carry fluid (drill mud) to the bit. The drill mud 

cools and lubricates the drill bit and the fluid performs an additional important function of carrying the 

cuttings made by the bit up to the surface and out of the hole. The drill mud is forced down the inside 

of the pipe and out through the bit to return to the surface in the annular space between the outside of 

the pipe and the sidewalls of the hole, washing the bit cuttings to the surface. Circulation is lost when 

the bit penetrates a porous zone, which allows the drill mud to leak away into the surrounding 

formation. As drill mud was released around the drill bit, it was made up from the mud pit as the 

drilling continued.

The drilling process continued after the drill bit had entered the fracture zone, with the continuing flow 

of drill mud around the drill bit. The mudflow helped to absorb radioactive particulates and the 

radioiodines, but the noble gases were not absorbed. Because the noble gases did not attach to the 

drill mud, they could be released up through the fracture zone around the drill string on to the drill 

platform area. This potentially resulted in a cloud of noble gases. The workers could have been in 

the noble gas clouds for several hours at a time over several days during the post-test drilling and 

core-sampling process. The possibility of long residence times for noble gases in the lungs is based 

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on the length of the exposure time. This situation continued until the introduction of blowout 

preventers (BOPs) in late 1964 (see Section D.4). Table D-2 lists the characteristics of the most 

common radioactive noble gases. Of these, 133,133mXe were the most prevalent at times greater than 2 

to 3 d after detonation.

Table D-2. Primary fission product noble gases with half-lives greater than 1 hr (for yields equal to or 

greater than 0.01 photon or beta per disintegration). 

Nuclide

X-ray emissiona Gamma emission Beta emission

Energy

(keV)

Yield

(X-rays/disb)

Energy

(keV)

Yield

(γ/dis)

Energy

(keV)

Yield

(β/dis)

Kr-85

(10.7 yr) - - - - 687 0.996

Kr-85m

(4.5 hr) - - 151 0.75 841 0.783 305 0.14

Kr-87

(76.3 m) - - 

403 0.496 924 0.044

674 0.019 1,330 0.094

845 0.073 1,470 0.055

1,175 0.011 3,040 0.073

1,740 0.020 3,482 0.41

2,012 0.029 3,885 0.305

2,555 0.092

2,558 0.039

Kr-88

(2.84 hr) - - 

27.5 0.019 366 0.026

166 0.031 522 0.670

196 0.260 682 0.091

362 0.022 1,199 0.020

835 0.130 1,732 0.010

986 0.013 2,052 0.013

1,141 0.013 2,718 0.021

1,251 0.011 2,914 0.140

1,370 0.015

1,518 0.022

1,530 0.109

2,030 0.045

2,035 0.037

2,196 0.132

2,232 0.034

2,392 0.346

Xe-133

(5.24 d)

30.6 0.144

81 0.380 346 0.99

31.0 0.265

34.9 0.025

35.0 0.048

35.8 0.015

Xe-133m

(2.19 d)

29.5 0.162

233 0.10 - - 29.8 0.299

33.6 0.080

34.4 0.016

Xe-135

(9.14 hr)

30.6 0.015 250 0.90 543 0.031

31.0 0.028 608 0.029 901 0.96

a. X-rays with energies greater than 15 keV.

b. dis = disintegration 

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Figure D-5 shows the flow of the drill mud. From the pump (A), the fluid goes to the swivel (B) down 

through the Kelly (C) through the drill stem (D) to the bit (E). At the bit, the drilling fluid washes the 

cuttings from the bit and the bottom of the hole and carries them back to the surface through the 

annulus (F). At the surface, a pipe carries the cuttings in suspension through a shale shaker (G), 

which removes the cuttings from the drilling fluid. From the shaker, the drilling fluid goes to the mud 

pit (H) and then down to the drill bit to the drilling area (Butler 1984).

Figure D-5. Circulation of drilling fluid. 

The radioiodines that escaped were considered primarily an internal thyroid organ exposure hazard, 

while the noble gases were of concern for immersion dose (external exposure) and lung dose. In 

addition, the drill mud trapped most of the radioiodines, which limited the release.

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D.3 Core Sampling

When the post-test hole had been drilled through the target zone as determined by the LLNL drilling 

engineers and the LANL J-6 NTS engineer, preparations were made to take puddle glass samples. 

The radionuclides present would be based on the time interval from test to sampling. A 

gamma-logging instrument was lowered inside the drill pipe to survey the puddle glass region. The 

laboratory drilling representative examined the gamma log and determined where the samples should 

be taken. When the decision to begin coring was made, the drill string had to be removed so that the 

Otis and coring subs could be placed in the drill string. The drill string (which now contained the 

sidewall sampler near its lower end) was pulled up the hole to place the sampling port in position for 

the first sample, the sidewall tool plug was pulled, and the sampling operation began.

LLNL and LANL used very similar sampling processes. The LLNL onsite representative (usually a 

radiochemist) along with an NTS Health and Safety representative provided direction on the 

hygrading, packaging, survey, and shipment. For LANL, the J-6 NTS representative was responsible 

for the coring operation and the LANL safety representative provided radiological safety operations 

coverage of the sampling. The LANL Isotope and Nuclear Chemistry (INC) Representative was 

responsible for providing sampling and downhole radiological monitoring and core sampling 

requirements including hygrading. The LANL INC representative was also responsible for packaging, 

onsite storage, and shipping of the core samples to Las Alamos for analysis through the J-3 NTS 

warehouse (Eberhart 1993).

For both laboratories the samples were taken with a sidewall sampling tool (Figure D-6), which cut 

into the wall of the hole to obtain cores about 1.5 in. in diameter by 6 in. long (LLNL used the Hunt

Tool or Homeco Tool, LANL used the Hunt Tool). Several core samples up to as high as a few dozen 

could normally be taken in a hole. The best samples were hygraded, selected, and put into a plastic 

container that was corked and placed in a lead pig. The samples were then prepared for shipment to 

the laboratory for analysis either through Warehouse No. 7 for LLNL (Butler 1984) or Warehouse J-3 

for LANL (Eberhart 1993). Both laboratories used tongs and extended tools for core hygrading. 

Although these samples, which read several roentgens per hour, were handled quickly, core-handling 

operations were a major exposure component.

D.4 Radioactivity Control Measures

The use of BOPs to contain the radioactive gases began in 1964. The containment equipment then 

consisted of three major components: the abandonment valve at the top of the preset casing, the ram 

unit (BOP) above it, and the rotating head (Figure D-7). 

The ram unit contained two sets of rams for shutting off flow: 1) blind rams that sealed the hole when 

the drill pipe was withdrawn (as when a bit or a tool was being changed), and 2) pipe rams that sealed 

off the space between the casing and the drill pipe when the drill pipe was in the hole. These rams 

could withstand pressures of 6,000 psi. The rotating head was lined with a thick rubber gasket that 

surrounded the drill pipe or Kelly and turned with it, which provided a low-pressure seal against 

escaping gas or fluid while drilling was in progress.

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Figure D-6. Four steps in taking a sidewall sample (Butler 1984).

Figure D-7. Blowout preventer. 

After the use of BOPs began, the first post-test drilling activity following detonation was the installation 

of the BOP on top of the preset casing. For low-yield tests, this installation could have occurred 

before the test. After the BOP was installed, the ventilation system was connected to the BOP and 

the drill rig cellar area. The ventilation system contained two sets of charcoal filter beds, 

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gas-sampling and analysis equipment, and 2,000-cfm blowers on each train that drew air from the 

BOP. The preset casing was several inches wider in diameter than the drill string. When circulation 

was lost, the radioactive gases that came up around the drill string (annulus) were pulled off through 

the BOP by the ventilation system. This reduced the noble gas doses on the drill rig platform.

Both LLNL and LANL used BOPs. The flow from the BOP, the cellar, and the flow through the 

sampling trailer to the ventilation systems were checked for normal operation before the start of LLNL 

drilling. LLNL had a core-hygrading trailer and a gas-sampling and analysis system hooked to the 

ventilation system. LANL used a post-test containment system that had a 20-ft stack using a BOP 

(Eberhart 1993). 

Other precautions were taken to reduce release of radioactivity to the surface after circulation was 

lost. Significant activity was trapped by the BOP and sent out through the ventilation system. 

However, a procedure of sending soap down the drill hole caused large quantities of bubbles to flow 

into the fracture zone, which also reduced gaseous releases. Some minor amounts could be released 

through the core-sampling process and through the drill stem, but the exposure was insignificant in 

comparison to the gas fields caused by loss of circulatory pressure before use of the BOPs. The use 

of BOPs, soap, and the ventilation systems resulted in a significant reduction in the exposure from the 

noble gases during drill-back operations.

D.5 Post-Test Radiation Monitoring

The LLNL NTS Health and Safety Engineers that supported a post-test drilling operation had three 

main responsibilities (Johnson et al. 1966, Appendix 8):

• To protect personnel from radiological and toxicological hazards

• To determine the type and amount of radioactive effluents

• To process radioactive core samples for shipment or storage

The Health and Safety engineers depended on REECo Rad-Safe as their main support unit. The 

routine sampling and monitoring program on the drill rigs and on the area perimeter was carried out 

by Rad-Safe under the overall coordination of LLNL NTS Health and Safety group. The sampling 

program was standardized as far as possible, and changes were made only when necessary because 

of changing conditions.

Protection of personnel from radiological and toxicological hazards was dependent on an effective 

monitoring program on the drill rigs. The drill rig monitoring program had been divided into two 

phases: Monitoring with portable instruments and monitoring with stationary instruments that either 

recorded automatically or gave remote readout and alarm at a central observation point.

Monitoring with portable instruments was carried out by Rad-Safe Monitors in areas where radiation 

release was most likely. Portable monitoring was usually reserved for critical periods of the post-test 

drilling operation and for investigating possible hazard situations indicated by the continuously 

monitoring stationary instruments. Any radiation above background levels was due either to a release 

of radioactive gas from the retention system or to the shine from a radioactive gas buildup within the 

system. Airborne gas was distinguished from shine by running a high-volume air sampler for a short 

period of time (usually 5 to 10 min) and then analyzing the sample.

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Continuous monitoring of the environmental air on the drill rig platform was accomplished by an array 

of four air-sampling heads on each corner of the platform. This array was activated when drilling 

began and operated continuously until the abandonment valve was closed. The results of this 

sampling gave an indication of the exposure, if any, to workers on the platform during the drilling 

operation.

REECo Rad-Safe monitors made routine hourly surveys of the drill platform and substructures, 

especially in the vicinity of the BOP and the cellar. During these surveys, the monitor determined the 

level of radioactivity, the presence and amount of any toxic gases, and the percentage of any 

explosive mixtures that could have been present. When work had to be performed during the release 

of radioactive gases (which could have caused increased dose rates), the Rad-Safe monitor 

periodically checked the workers' personal dosimeters to control excessive exposures. At times when 

airborne radioactivity was detected and it was necessary to require personnel to wear respiratory 

gear, the Rad-Safe monitors checked to see that the respiratory protection was fitted properly and 

being worn correctly. The half-face and full-face respirators were not effective for removing noble 

gases, but were effective for the removal of radioiodines, radioactive particulates, and toxic materials. 

If self-contained breathing apparatus was worn, it was effective in eliminating the noble gas exposure, 

but required periodic air bottle change outs. 

Monitoring with remote readout and automatic stationary instruments was standardized and consisted 

of the following:

• 1 remote air monitoring (RAM) unit on the drill platform for monitoring gamma intensities.

• 1 RAM unit on the mud return line for monitoring gamma intensities (Both of these RAM units 

had their readouts in the Rad-Safe base station trailer and were recorded on charts).

• 1 gate alarm on the mud return line near the BOP. This unit was generally set to alarm at 

some point just above normal background; the alarm was positioned where it could be easily 

seen or heard by the driller.

• 1 gamma alarm on the mast. This instrument was generally set to alarm at about 5 mR/hr.

• 1 CO2 alarm with its sensing unit near the BOP and its alarm near the driller.

Standard perimeter sampling consisted of an array of 8 to 16 air-sampling trailers (in multiples of 4) 

and the same number of RAMs evenly spaced around a circle of 1,000 ft or greater radius that 

covered the drill rig area. Air samples were changed every 8 hr to provide a record of release on any 

given shift. Rad-Safe had standing instructions to report any radioactivity levels above background to 

the LLNL Health and Safety engineer and the LANL safety representative (Eberhart 1993) and to 

keep them informed as conditions changed. All necessary Anti-C clothing and respiratory gear was 

provided by Rad-Safe. Both LLNL and LANL workers were trained in the use of the various types of 

respiratory protection equipment (Johnson et al. 1966) and (Eberhart 1993) 

An LLNL stack monitor trailer near the vent line blower to monitor for radioactive effluent was standard 

equipment on all post-test drilling operations. If present, radioactive effluent picked up by the 

ventilation system was first drawn through a charcoal filter bed, just beyond which Rad-Safe operated 

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a sequential charcoal filter to sample a small amount of the vent line air. Any iodine not filtered out in 

the charcoal filter bed was picked up by this sequential sampler, which consisted of 12 charcoal 

air-filter heads set to operate 2 hr each for a total of 24 hr. The changeover from one filter to the next 

occurred sequentially and automatically.

LANL had similar monitoring systems in its Rad Lab Trailer, which was under the direction of LANL

and was supported by REECo Rad Safe. LANL also had the safety representative on the site for the 

entire post-test drilling campaign to provide technical direction to the Rad Safe Monitors through 

coring and gas sampling if required until site closure. This representative provided technical support 

to the INC Representative for core sampling, analysis, and preparation for core shipments to Las 

Alamos (Eberhart 1993) 

To monitor high-level releases, Health and Safety operated three RAM units on the vent line—one in 

front of the charcoal filter, one on the charcoal filter, and one after the charcoal filter—that were read 

in the stack monitor trailer. Releases of a low or intermediate nature were determined by drawing a 

small volume of the vent-line air through tubing into the stack monitor trailer. The air was scanned by 

a scintillation system, and the counts were registered on a scaler unit and recorded periodically on 

tape. If counts in excess of normal background were encountered, they were manipulated with 

suitable equations to compute the quantity of the release. The velocity of the vent-line air, generally 

1,000 to 1,500 ft/min, was automatically recorded in the stack trailer. The stack trailer was equipped 

with a remote audible alarm in the form of an electronic siren and a visible alarm in the form of colored 

lights on the end of the trailer. The alarm systems could be preset to trip at any predetermined level. 

The LANL monitoring system was very similar, and the Rad Safe support was under the technical 

direction of their HSE-1 representative.

The last function of LLNL NTS Health and Safety, to provide technical direction for processing 

radioactive core samples for shipment, was accomplished in the following manner. When the core 

samples had been selected for shipment, the Health and Safety engineer had Rad-Safe place them in 

pigs and identify each pig with the number of the sample it contained. The Health and Safety 

engineer then monitored the pigs and attached shipment tags. At this point, the cores for shipment 

were sent to Warehouse No. 7, and the backup samples were taken for storage in the core library.

As soon as the abandonment valve was closed and determined to be free of leaks, Rad-Safe placed 

an air-sampling unit next to the cellar. This air-sampling unit operated continuously for 48 hr to 

monitor for delayed leaks.

As stated above, the LANL INC representative was also responsible for packaging, onsite storage, 

and shipping of the core samples to Las Alamos for analysis through the J-3 NTS warehouse 

(Eberhart 1993).

D.6 Exposed Workers

Workers normally present at the time of gaseous releases were REECo drillers, roughnecks, 

equipment oilers, and Rad Safe monitors. Health physics professionals from LLNL, LANL, and 

REECo were also present on the drill rigs. Sampling personnel who prepared the core samples for 

analysis were exposed to direct radiation from the core samples and were a part of this work group. 

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After the BOPs were used for post-test drilling, this group of workers was the workers exposed if 

gaseous releases occurred. 

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