The Containment of Underground Nuclear

Explosions

October 1989

NTIS order #PB90-156183
g, gy , f g

Explosions, OTA-ISC-414 (Washington, DC: U.S. Government Printing Office, October

1989),

Library of Congress Catalog Card Number 89-600707

For sale by the Superintendent of Documents

U.S. Government Printing Office, Washington, DC 20402-9325

(order form can be found in the back of this report)
Foreword

Within weeks after the ending of World War II, plans for the first nuclear test series

“Operation Crossroads” were underway. The purpose then, as now, was to develop new

weapon systems and to study the effects of nuclear explosions on military equipment. The

development of the nuclear testing program has been paralleled by public opposition from both

an arms control and an environmental perspective. Much of the criticism is due to the symbolic

nature of testing nuclear weapons and from the radiation hazards associated with the early

practice of testing in the atmosphere. Recently, however, specific concerns have also been

raised about the current underground testing program; namely:

. Are testing practices safe?

. Could an accidental release of radioactive material escape undetected?

● Is the public being fully informed of all the dangers emanating from the nuclear testing

program?

These concerns are fueled in part by the secrecy that surrounds the testing program and by

publicized problems at nuclear weapons production facilities.

At the request of the House Committee on Interior and Insular Affairs and Senator Orrin

G. Hatch, OTA undertook an assessment of the containment and monitoring practices of the

nuclear testing program. This special report reviews the safety of the nuclear testing program

and assesses the technical procedures used to test nuclear weapons and ensure that radioactive

material produced by test explosions remains contained underground. An overall evaluation

considers the acceptability of the remaining risk and discusses reasons for the lack of public

confidence.

In the course of this assessment, OTA drew on the experience of many organizations and

individuals. We appreciate the assistance of the U.S. Government agencies and private

companies who contributed valuable information, the workshop participants who provided

guidance and review, and the many additional reviewers who helped ensure the accuracy and

objectivity of this report.

,..

Ill
Workshop 1: Containment

Monday, Sept. 26,1988

Environmental Research Center

University of Nevada, Las Vegas

Neville G. Cook, Chair

Department of Material Science and Mineral Engineering

University of California

Frederick N. App

Section Leader

Containment Geophysics

Los Alamos National Laboratory

Norman R. Burkhard

Containment Program Leader

Lawrence Livermore National Laboratory

Jim Carothers

Chairman

Containment Evaluation Panel

Lawrence Livermore National Laboratory

Jack Evernden

Lawrence Livermore National Laboratory

U.S. Geological Survey

Robert A. Fulkerson

Executive Director

Citizen Alert

Jack W. House

Containment Program Manager

Los Alamos National Laboratory

Evan Jenkins

U.S. Geological Survey

Joseph LaComb

Chief

Nevada Operations Office

Defense Nuclear Agency

James K. Magruder

Assistant Manager for Operations and Engineering

Nevada Operations Office

U.S. Department of Energy

Paul Orkild

U.S. Geological Survey

Edward W. Peterson

Containment Project Director

S-CUBED

John Stewart

Director

Test Operations Division

Nevada Operations Office

U.S. Department of Energy

Billy C. Hudson

Deputy Containment Program Leader

Lawrence Livermore National Laboratory

iv
Workshop 2: Monitoring

Tuesday, Sept. 27, 1988

Environmental Research Center

University of Nevada, Las Vegas

Melvin W. Carter, Chair

Neely Professor Emeritus

Georgia Institute of Technology

Lynn R. Anspaugh

Division Leader

Environmental Sciences Division

Lawrence Livermore National Laboratory

Bruce Church

Assistant Manager for Environmental Safety and

Health

Nevada Operations Office

U.S. Department of Energy

Charles F. Costa

Director

Nuclear Radiation Assessment Division

United States Environmental Protection Agency

Donald R. Elle

Chief, Technical Projects Branch

Health Physics and Environmental Division

Nevada Operations Office

U.S. Department of Energy

Bernd Franke

IFEU

Robert A. Fulkerson

Executive Director

Citizen Alert

Michael A. Marelli

Chief, Health Protection Branch

Health Physics and Environmental Division

Nevada Operations Office

U.S. Department of Energy

Darryl Randerson

Weather Service

Nuclear Office
OTA Project Staff-The Containment of Underground Nuclear Explosions

Lionel S. Johns, Assistant Director, OTA

Energy, Materials, and International Security Division

Peter Sharfman, International Security and Commerce Program Manager*

Alan Shaw, International Security and Commerce Program Manager**

Gregory E. van der Vink, Project Director

Administrative Staff

Jannie Horne (through November 1988)

Marie C. Parker (through April 1989)

Jackie Robinson

Louise Staley

“Through February 1989.

● *From March 1989.

vi
Acknowledgments

OTA gratefully acknowledges the valuable contributions made by the following:

Lynn R. Anspaugh

Lawrence Livermore National Laboratory

Frederick N. App

Los Alamos National Laboratory

Nick Aquilina

U.S. Department of Energy

Charles Archambeau

CIRES, University of Colorado, Boulder

Stuart C. Black

U.S. Environmental Protection Agency

Carter Broyles

Sandia National Laboratory

Norman R. Burkhard

Lawrence Livermore National Laboratory

John H. Campbell

U.S. Department of Energy

Jim Carothers

Lawrence Livermore National Laboratory

Melvin W. Carter

International Radiation Protection Consultant

Bruce Church

U.S. Department of Energy

Neville G. Cook

University of California, Berkeley

Charles F. Costa

U.S. Environmental Protection Agency

Jeff Duncan

Office of Congressman Edward J. Markey

Donald R. Elle

U.S. Department of Energy

Gerald L. Epstein

John F. Kennedy School of Government, Harvard University

Jack Evernden

U.S. Geological Survey

Anthony Fainberg

Office of Technology Assessment, U.S. Congress

Pete Fitzsimmons

U.S. Department of Energy

Janet Fogg

U.S. Department of Energy

Bernd Franke

IFEU

Robert A. Fulkerson

Citizen Alert

Larry Gabriel

Defense Nuclear Agency

David Graham

Moore College of Art

Jack W. House

Los Alamos National Laboratory

Billy C. Hudson

Lawrence Livermore National Laboratory

Evan Jenkins

U.S. Geological Survey

Gerald W. Johnson

University of California

Joseph W. LaComb

Defense Nuclear Agency

James K. Magruder

U.S. Department of Energy

Michael A. Marelli

U.S. Department of Energy

LTC Samuel D. McKinney

Defense Nuclear Agency

David N. McNelis

University of Las Vegas, Nevada

Paul Orkild

Lawrence Livermore National Laboratory

Edward W. Peterson

S-CUBED

Dorothy F. Pope

Defense Nuclear Agency

Darryl Randerson

Weather Service, Nuclear Office

Karen Randolph

U.S. Department of Energy

R.L. Rhodes

Diebold, Inc.

Patrick Rowe

REECo

Robert Shirkey

Defense Nuclear Agency

John O. Stewart

U.S. Department of Energy

Robert Titus

Weather Service, Nuclear Office

Dean R. Townsend

Fenix & Scission, Inc.

Chris L. West

U.S. Department of Energy

Barbara Yoers

U.S. Department of Energy

NOTE: OTA appreciates and is grateful for the valuable assistance and thoughtful critiques provided by the contributors. The

contributors do not, however, necessarily approve, disapprove, or endorse this report. OTA assumes full responsibility for the

report and the accuracy of its contents. Vil
Page

Chapter 1. Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 2. The Nuclear Testing Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 3. Containing Underground Nuclear Explosions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 4. Monitoring Accidental Radiation Releases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

11

31

59
Chapter 1

Executive Summary
CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

HOW SAFE IS SAFE ENOUGH? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

HOW SAFE HAS IT BEEN? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

SPECIFIC CONCERNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

OVERALL EVALUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Table

Table Page

l-1. Releases From Underground Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Chapter 1

Executive Summary

The chances of an accidental release of radioactive material have been made as remote as possible.

Public concerns about safety are fueled by concerns about the testing program in general and

exacerbated by the government’s policy of not announcing all tests.

INTRODUCTION

During a nuclear explosion, billions of atoms

release their energy within a millionth of a

second, pressures reach several million pounds

per square inch, and temperatures are as high as

one-million degrees centigrade. A variety of

radioactive elements are produced depending on

the design of the explosive device and the

contribution of fission and fusion to the explosion. The half-lives of the elements produced

range from less than a second to more than a

million years.

Each year over a dozen nuclear weapons are

detonated underground at the Nevada Test Site.l

The tests are used to develop new nuclear

weapons and to assess the effects of nuclear

explosions on military systems and other hardware. Each test is designed to prevent the release

of radioactive material. The objective of each

test is to obtain the desired experimental information and yet successfully contain the explosion underground (i.e., prevent radioactive material from reaching the atmosphere).

HOW SAFE IS SAFE ENOUGH?

Deciding whether the testing program is safe

requires a judgment of how safe is safe enough.

The subjective nature of this judgment is

illustrated through the decision-making process

of the Containment Evaluation Panel (CEP)

which reviews and assesses the containment of

each test.2 The panel evaluates the probability of

containment using the terms "high confidence,"

‘‘adequate degree of confidence, ’ and ‘‘some

doubt. ” But the Containment Evaluation Panel

has no guidelines that attempt to quantify or

describe in probabilistic terms what constitutes

for example, an “adequate degree of confidence." Obviously, there can never be 100

percent confidence that a test will not release

radioactive material. Whether ‘‘adequate confidence” translates into a chance of 1 in 100, 1 in

1,000, or 1 in 1,000,000, requires a decision

about what is an acceptable level of risk. In turn,

decisions of acceptable level of risk can only be

made by weighing the costs of an unintentional

release against the benefits of testing. Consequently, those who feel that testing is important

for our national security will accept greater risk,

and those who oppose nuclear testing will find

even small risks unacceptable.

Establishing an acceptable level of risk is

difficult, not only because of the value judgments associated with nuclear testing, but also

because the risk is not seen as voluntary by those

outside the testing program. A public that

readily accepts the risks associated with voluntary activities—such as skydiving or smoking—

may still consider the much lower risks associated with nuclear testing unacceptable.

HOW SAFE HAS IT BEEN?

Some insight into the safety of the nuclear

testing program can be obtained by reviewing

the containment record. Releases of radioactive

material are categorized with terms that describe

both the volume of material released and the

conditions of the release:

s

l~ently, ~1 U,S. nuclew test explosions are conduct~ at the Nevada lkst Site.

zfie Conttimen[ Evaluation pmel is a group of representa[lves from v~ious la~ratories and technical consulting orgamzations who evaluate the

proposed containment plan for each test without regard to cost or other outside considerations (see ch, 2 for a complete di.scusslon).

-3–
4 ● Containment of Underground Nuclear Explosions

Containment Failures: Containment failures are unintentional releases of radioactive

material to the atmosphere due to a failure of the

containment system. They are termed “ventings, “ if they are prompt, massive releases; or

“seeps,” if they are slow, small releases that

occur soon after the test.

Late-Time Seeps: Late-time seeps are small

releases that occur days or weeks after a test

when gases diffuse through pore spaces of the

overlying rock and are drawn to the surface by

decreases in atmospheric pressure.

Controlled Tunnel Purging: A controlled

tunnel purging is an intentional release to allow

either recovery of experimental data and equipment or reuse of part of the tunnel system.

Operational Release: Operational releases

are small, consequential releases that occur

when core or gas samples are collected, or when

the drill-back hole is sealed.

The containment record can be presented in

different ways depending on which categories of

releases are included. Reports of total numbers of releases are often incomplete because

they include only announced tests or releases

due to containment failure. The upper portion

of table 1-1 includes every instance (for both

announced and unannounced tests) where radioactive material has reached the atmosphere

under any circumstances whatsoever since

the 1970 Baneberry test.

Since 1970, 126 tests have resulted in radioactive material reaching the atmosphere with a

total release of about 54,000 Curies (Ci). Of this

amount, 11,500 Ci were due to containment

failure and late-time seeps. The remaining

42,500 Ci were operational releases and controlled tunnel purgings-with Mighty Oak (36,000

Ci) as the main source. The lower portion of the

table shows that the release of radioactive

material from underground nuclear testing since

Baneberry (54,000 Ci) is extremely small in

comparison to the amount of material released

Table I-l-Releases From Underground Tests

(normalized to 12 hours after event)

All releases 1971 -1988:

Containment Failures:

Camphor, 1971b . . . . . . . . . . . . . . . . . . . . . .........360 Ci

Diagonal Line, 1971 . . . . . . . . . . . . . . . . . .........6,800

Riola, 1980 . . . . . . . . . . . . . . . . . ................3,100

Agrini, 1984 . . . . . . . . . . . . . . . . . ................690

Late-time Seeps:

Kappeli, 1984 . . . . . . . . . . . . . . . . . . . . . . . . . . .......12

Tierra, 1984 . . . . . . . . . . . . . . . . . .................600

Labquark, 1986 . . . . . . . . . . . . . . . . . . . . . . . . .......20

Bodie, 19863 . . . . . . . . . . . . . . . . . . . . . . . . . . . .......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, 1986 . . . . . . . . . . . . . . . . . ..........36,000

Mission Ghost, 1987C . . . . . . . . . . . . . . . . . . . . .. ......3

Operational Releases:

108 tests from 1970-1988d . . . . . . . . . . . . . . . . . . . . .. 5,500

Total since Baneberry: 54,000 Ci

Major pre-1971 releases:

Platte, 1962 . . . . . . . . . . . . . . . . . ............1,900,000 Ci

Eel, 1962 . . . . . . . . . . . . . . . . . .............1,900,000

Des Moines, 1962 . . . . . . . . . . . . . . . . . . . . . . 11,000,000

Baneberry, 1970 . . . . . . . . . . . . . . . . . .......6,700,000

26 others from 1958-1970 . . . . . . . . . . . . . . ...3,800,000

Total: 25,300,000 Ci

Other Releases for Reference

NTS Atmospheric Testing 1951-1963: . .12,000,000,000 Ci

1 Kiloton Aboveground Explosion: . ........10,000,000

Chernobyl (estimate):. . . . . . . . . . . . . .......81 ,000,000

aR+12 values apply only to containment failures, others are at tlfne Of

release.

%he Camphor failure includes 140 Ci from tunnel purging.

c~ie and Mission Ghost also had drill-back releases.

dMany of the= operational rele~s are assoaated with tests that were not

announced.

SOURCE: Office of Technology Assessment, 1989.

by pre-Baneberry underground tests (25,300,000

Ci), the early atmospheric tests at the Nevada

Test Site (12,000,000,000 Ci), or even the

amount that would be released by a single

l-kiloton explosion conducted aboveground

(10,000,000 Ci).

From the perspective of human health risk:

If the same person had been standing at the

boundary of the Nevada Test Site in the area

of maximum concentration of radioactivity

for every test since Baneberry (1970), that
Chapter 1---Executive Summary ● 5

person’s total exposure would be equivalent

to 32 extra minutes of normal background

exposure (or the equivalent of 1/1000 of a

single chest x-ray).

A worst-case scenario for a catastrophic

accident at the test site would be the prompt,

massive venting of a 150-kiloton test (the largest

allowed under the 1974 Threshold Test Ban

Treaty). The release would be in the range of 1

to 10 percent of the total radiation generated by

the explosion (compared to 6 percent released

by the Baneberry test or an estimated 10 percent

that would be released by a test conducted in a

hole open to the surface). Such an accident

would be comparable to a 15-kiloton above-

-ground test, and would release approximately

150,000,000 Ci. Although such an accident

would be considered a major catastrophe today,

during the early years at the Nevada Test Site 25

aboveground tests had individual yields equal

to or greater than 15 kilotons.

SPECIFIC CONCERNS

Recently, several specific concerns about the

safety of the nuclear testing program have

arisen, namely:3

1. Does the fracturing of rock at Rainier Mesa

pose a danger?

The unexpected formation of a surface collapse crater during the 1984 Midas Myth test

focused concern about the safety of testing in

Rainier Mesa. The concern was heightened by

the observation of ground cracks at the top of the

Mesa and by seismic measurements indicating

a loss of rock strength out to distances greater

than the depth of burial of the nuclear device.

The specific issue is whether the repeated testing

in Rainier Mesa had fractured large volumes of

rock creating a “tired mountain’ that no longer

had the strength to successfully contain future

underground tests. The inference that testing in

Rainier Mesa poses a high level of risk implies

that conditions for conducting a test on Rainier

are more dangerous than conditions for conducting a test on Yucca Flat.4 But, in fact, tests in

Rainier Mesa are buried deeper and spaced

further apart than comparable tests on Yucca

Flat.5 Furthermore, drill samples show no evidence of any permanent decrease in rock

strength at distances greater than two cavity

radii from the perimeter of the cavity formed by

the explosion. The large distance of decreased

rock strength seen in the seismic measurements

is almost certainly due to the momentary

opening of pre-existing cracks during passage of

the shock wave. Most fractures on the top of the

mesa are due to surface span and do not extend

down to the region of the test. Furthermore, only

minimal rock strength is required for containment. Therefore, none of the conditions of

testing in Rainier Mesa—burial depth, separation distance, or material strength—imply

that leakage to the surface is more likely for

a tunnel test on Rainier Mesa than for a

vertical drill hole test on Yucca Flat.

2. Could an accidental release of radioactive

material go undetected?

A comprehensive system for detecting radioactive material is formed by the combination of:

. the monitoring system deployed for each

test;

. the onsite monitoring system run by the

Department of Energy (DOE) and;

. the offsite monitoring system, run by

Environmental Protection Agency (EPA),

including the community monitoring stations.

There is essentially no possibility that a

significant release of radioactive material

3W(~l~ an~ysis of tiese concerns is included in chs. 3 and 4.

4A~~oximaIely ~~rcent of ~] nuclew test explosions are vertical drill hole tests conducted on Yucca Hal. SW ch. 2 for an exPl~ation of the

various types of tests,

s~e ~ea~r dep~ of burial is due to convenience. It is easier to mine tLUtIMk ]OWW h the Mesa.
6 ● Containment of Underground Nuclear Explosions

from an underground test could go undetected.

3. Are we running out of room to test at the

Test Site?

Efforts to conserve space for testing in

Rainier Mesa have created the impression that

there is a‘ ‘real estate problem” at the test site.6

The concern is that a shortage of space would

result in unsafe testing practices. Although it is

true that space is now used economically to

preserve the most convenient locations, other

less convenient locations are available within

the test site. Suitable areas within the test site

offer enough space to continue testing at

present rates for several more decades.

4. Do any unannounced tests release radioactive material?

A test will be preannounced in the afternoon

2 days before the test if it is determined that the

maximum possible yield of the explosion is such

that it could result in perceptible ground motion

in Las Vegas. An announcement will be made

after a test if there is a prompt release of

radioactive material, or if any late-time release

results in radioactivity being detected off the test

site. The Environmental Protection Agency is

dependent on the Department of Energy for

notification of any late-time releases within the

boundaries of the test site. However, if EPA is

not notified, the release will still be detected by

EPA’s monitoring system once radioactive material reaches outside the test site. If it is judged

that a late-time release of radioactive material will not be detected outside the boundaries of the test site, the test may (and often

does) remain unannounced.

OVERALL EVALUATION

Every nuclear test is designed to be contained

and is reviewed for containment.7 In each step of

the test procedure there is built-in redundancy

and conservatism. Every attempt is made to

keep the chance of containment failure as

remote as possible. This conservatism and

redundancy is essential, however; because no

matter how perfect the process may be, it

operates in an imperfect setting. For each test,

the containment analysis is based on samples,

estimates, and models that can only simplify and

(at best) approximate the real complexities of

the Earth. As a result, predictions about containment depend largely on judgments developed

from past experience. Most of what is known to

cause problems--carbonate material, water,

faults, scarps, clays, etc.—was learned through

experience. To withstand the consequences of a

possible surprise, redundancy and conservatism

is a requirement not an extravagance. Consequently, all efforts undertaken to ensure a safe

testing program are necessary, and must continue to be vigorously pursued.

The question of whether the testing program

is ‘‘safe enough’ will ultimately remain a value

judgment that weighs the importance of testing

against the risk to health and environment. In

this sense, concern about safety will continue,

largely fueled by concern about the nuclear

testing program itself. However, given the

continuance of testing and the acceptance of the

associated environmental damage, the question

of ‘adequate safety’ becomes replaced with the

less subjective question of whether any improvements can be made to reduce the chances

of an accidental release. In this regard, no areas

for improvement have been identified. This is

not to say that future improvements will not be

made as experience increases, but only that

essentially all suggestions that increase the

safety margin have been implemented. The

safeguards built into each test make the

chances of an accidental release of radioactive material as remote as possible.

6SW for ex~ple: William J. Broad, “Bomb l&Is: Txhnology Advances Against Backdrop of Wide Debate,” New York Times, Apr. 15, 1986,

pp. C1-C3.

7SW Ch. 3 for a de[ajl~ accounting of the review process.
Chapter 1—Executive Summary ● 7

The acceptability of the remaining risk will

depend on public confidence in the nuclear

testing program. This confidence currently suffers from a lack of confidence in the Department

of Energy emanating from problems at nuclear

weapons production facilities and from radiation hazards associated with the past atmospheric testing program. In the case of the present

underground nuclear testing program, this mistrust is exacerbated by DOE’s reluctance to

disclose information concerning the testing

program, and by the knowledge that not all tests

releasing radioactive material to the atmosphere

(whatever the amount or circumstances) are

announced. As the secrecy associated with the

testing program is largely ineffective in preventing the dissemination of information concerning

the occurrence of tests, the justification for such

secrecy is questionable.8

The benefits of public dissemination of information have been successfully demonstrated by the

EPA in the area of radiation monitoring. Openly

available community monitoring stations allow

residents near the test site to independently

verify information released by the government,

thereby providing reassurance to the community

at large. In a similar manner, public concern

over the testing program could be greatly

mitigated if a policy were adopted whereby

all tests are announced, or at least all tests

that release radioactive material to the atmosphere (whatever the conditions) are announced.

8SCC for Cxmple: Rdey R. Ge~t “Nevada RX Site’s dirty little secrets, ” Bulletin of the Atomic Scientists, April 1989, pp. 35-38,
Chapter 2

The Nuclear Testing Program
CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

THE HISTORY OF NUCLEAR TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

LIMITS ON NUCLEAR TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

OTHER LOCATIONS OF NUCLEAR TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

THE NEVADA TEST SITE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

TYPES OF NUCLEAR TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

ANNOUNCEMENT OF NUCLEAR TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

DETONATION AUTHORITY AND PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figures

Figure Page

2-1. U.S Nuclear Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2-2. Nevada Test Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2-3. Drill-Back Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2-4. Locations of Tunnel Tests in Rainier and Aqueduct Mesas . . . . . . . . . . . . . . . . . . . . . . . 21
Chapter 2

The Nuclear Testing Program

The nuclear testing program has played a major role in developing new weapon systems and

determining the effects of nuclear explosions.

INTRODUCTION

In the past four decades, nuclear weapons have

evolved into highly sophisticated and specialized

devices. Throughout this evolution, the nuclear

testing program has played a major role in developing new weapon systems and determining the effects

of nuclear explosions.

THE HISTORY OF NUCLEAR

TESTING

On July 16, 1945 the world’s first nuclear bomb

(code named “Trinity”) was detonated atop a

100-foot steel tower at the Alamogordo Bombing

Range, 55 miles northwest of Alamogordo, New

Mexico.l The explosion had a yield of 21 kilotons

(kts), the explosive energy equal to approximately

21,000 tons of TNT.2 The following month, American planes dropped two atomic bombs (’‘Little

Boy,’ ‘ 13 kilotons; ‘‘Fat Man, ” 23 kilotons) on the

Japanese cities of Hiroshima and Nagasaki, ending

World War II and beginning the age of nuclear

weapons.

3

Within weeks after the bombing of Hiroshima and

Nagasaki, plans were underway to study the effects

of nuclear weapons and explore further design

possibilities. A subcommittee of the Joint Chiefs of

Staff was created, on November 10, 1945, to arrange

the first series of nuclear test explosions. President

Truman approved the plan on January 10, 1946. The

Bikini Atoll was selected as the test site and the

Bikinians were relocated to the nearby uninhabited

Rongerik Atoll. Two tests (“Able” and “Baker*’)

were detonated on Bikini in June and July of 1946 as

part of “Operation Crossroads,” a series designed to

study the effects of nuclear weapons on ships,

equipment, and material.4 The Bikini Atoll, however, was found to be too small to accommodate

support facilities for the next test series and so

“Operation Sandstone” was conducted on the

nearby Enewetak Atoll. The tests of Operation

Sandstone (“ X-ray,” “ Yoke,” and “Zebra’ were

proof tests for new bomb designs.

As plans developed to expand the nuclear arsenal,

the expense, security, and logistical problems of

testing in the Pacific became burdensome. Attention

turned toward establishing a test site within the

continental United States. The Nevada Test Site was

chosen in December 1950 by President Truman as a

continental proving ground for testing nuclear weapons. A month later, the first test-code named

“Able’ ’-was conducted using a device dropped

from a B-50 bomber over Frenchman Flat as part of

a five-test series called “Operation Ranger. ’ The

five tests were completed within 11 days at what was

then called the ‘‘Nevada Proving Ground. "

Although the Nevada Test Site was fully operational by 1951, the Pacific continued to be used as a

test site for developing thermonuclear weapons (also

called hydrogen or fusion bombs), On October 31,

1952, the United States exploded the first hydrogen

(fusion) device on Enewetak Atoll.5 The test, code

named “Mike,’ had an explosive yield of 10,400

kilotons-over 200 times the largest previous test.

I The A]~ogordo Bombing Range is now the White Sands Missile Range.

2A kiloton (kl) was o~~n~]y defined as the explosive equivalent of 1,~ tons of TNT. This dcfitition, however, was found 10 bC Imprecise for IWO

reasons. First, there is some variation in the experimental and theoretical vatues of the explosive energy released by TNT (although [hc majority of values

lie in the range from 900 to 1,100 calories per gram). Second, the term kiloton coutd refer to a short kiloton (2xl@ pounds), a metric kiloton (2.205X 1(Y’

pounds), or a long kiloton (2.24x I@’ pounds). II was agreed, therefore, during the Manhattan Project that the term “kiloton’ would refer to the rclcaw

of 101 ~ ( 1 ,000,000,000,000) caloncs of explosive energy.

JJohn Malik, ‘‘The Yields of the Hiroshima and Nagasaki Nuclear Explosions, ’ l-m Alamos National Laboratory repor[ LA-8819, 1985.

dThc ~tiget ~onslsted of a fleet of over 90 vc~wls aswmbled in [hc Bikini Lagoon including [hrcc captured German and Japanese ships; SUrplUS U.S.

cruisers, destroyers, and submarines; and amphlbmus craft.

~The first test of ~ actual hydrogen bomb (rather [han a device located on the sUrfaCe) wa.. ‘ ‘Cherokee which was dropped from a plane over Bikml

Atoll on May 20, 1956. Extenslvc preparations were made for the test that included the consuuctlon of artificial islands 10 house measuring cquipmcnl

The elaborate experiments required that the bomb be dropped in a precise location in space. To accomplish this, the Stra[eglc Air Command held a

competition for bombing accuracy. Although the winner hit the correct point in every practice run, during the test the bomb was dropped 4 miles off-target.

-11-
12 ● The Containment of Underground Nuclear Explosions

The test was followed 2 weeks later by the 500

kiloton explosion “King,” the largest fission weapon

ever tested.

At the Nevada Test Site, low-yield fission devices

continued to be tested. Tests were conducted with

nuclear bombs dropped from planes, shot from

cannons, placed on top of towers, and suspended

from balloons. The tests were designed both to

develop new weapons and to learn the effects of

nuclear explosions on civilian and military structures. Some tests were conducted in conjunction

with military exercises to prepare soldiers for what

was then termed “the atomic battlefield. ”

In the Pacific, the next tests of thermonuclear

(hydrogen) bombs were conducted under “Operation Castle,’ a series of six tests detonated on the

Bikini Atoll in 1954. The first test, “Bravo,” was

expected to have a yield of about 6,000 kilotons. The

actual yield, however, was 15,000 kilotons-over

twice what was expected.6 The radioactive fallout

covered an area larger than anticipated and because

of a faulty weather prediction, the fallout pattern was

more easterly than expected. A Japanese fishing

boat, which had accidentally wandered into the

restricted zone without being detected by the Task

Force, was showered with fallout. When the fishing

boat docked in Japan, 23 crew members had

radiation sickness. The radio operator died of

infectious hepatitis, probably because of the large

number of required blood transfusions.7 The faulty

fallout prediction also led to the overexposure of the

inhabitants of two of the Marshall Islands 100 miles

to the East. In a similar though less severe accident,

radioactive rain from a Soviet thermonuclear test fell

on Japan.* These accidents began to focus worldwide attention on the increased level of nuclear

testing and the dangers of radioactive fallout. Public

opposition to atmospheric testing would continue to

mount as knowledge of the effects of radiation

increased and it became apparent that no region of

the world was untouched.9

Attempts to negotiate a ban on nuclear testing

began at the United Nations Disarmament Conference in May 1955. For the next several years efforts

to obtain a test ban were blocked as agreements in

nuclear testing were linked to progress in other arms

control agreements and as differences over verification requirements remained unresolved. In 1958,

President Eisenhower and Soviet Premier Khrushchev

declared, through unilateral public statements, a

moratorium on nuclear testing and began negotiations on a comprehensive test ban. The United States

adopted the moratorium after conducting 13 tests in

seven days at the end of October 1958. Negotiations

broke down first over the right to perform onsite

inspections, and then over the number of such

inspections. In December 1959, President Eisenhower announced that the United States would no

longer consider itself bound by the “voluntary

moratorium” but would give advance notice if it

decided to resume testing. Meanwhile (during the

moratorium), the French began testing their newly

acquired nuclear capability. The Soviet Union,

which had announced that it would observe the

moratorium as long as the western powers would not

test, resumed testing in September 1961 with a series

of the largest tests ever conducted. The United States

resumed testing two weeks later (figure 2-1).10

Public opposition to nuclear testing continued to

mount. Recognizing that the U.S. could continue its

development program solely through underground

testing and that the ratification of a comprehensive

test ban could not be achieved, President Kennedy

proposed a limited ban on tests in the atmosphere,

the oceans, and space. The Soviets, who through

their own experience were convinced that their test

program could continue underground, accepted the

proposal. With both sides agreeing that such a treaty

could be readily verified, the Limited Test Ban

Treaty (LTBT) was signed in 1963, banning all

aboveground or underwater testing.

In addition to military applications, the engineering potential of nuclear weapons was recognized by

the mid-1950’s. The Plowshare Program was formed

in 1957 to explore the possibility of using nuclear

explosions for peaceful purposes.l1 Among the -

bBravo wss tie ]~gest test ever detonated by the United States.

7SW 4‘ne Voyage of the Lucky Dragon, ” Ralph E. Lapp, 1957, Harper& Brothers Publishers, New York.

8“Arrns Control and Disarmament Agreements, ” United States Arms Control and Disarmament Agency, Washington, DC, 1982 Edition, p. 34.

psi~e tie l~ge herrnonuc]ew tests, all pmple have strontium-90 (a sister element of calcium) in their bones, and cesium-137 (a sister element Of

potassium) in their muscle. Also, the amount of iodine-131 in milk in the United States correlates with the frequency of atmospheric testing.

1OSW c *Ares con~oj and Disarmament Agreements, ’ United States Arms Control and Disarmament Agency, 1982 edition.

1 l~e n~e is fi~ “. . . . they shall beat their swords into plowshares,” Isaiah 2:4.
Chapter 2—The Nuclear Testing Program 13

Figure 2-1—U.S. Nuclear Testing

1945 1950 1955 1960 1965 1970 1975 1980 1985

n Above-ground tests Years

u

Underground tests

SOURCE: Data from the Swedish Defense Research Institute.

applications considered were the excavation of

canals and harbors, the creation of underground

storage cavities for fuel and waste, the fracturing of

rock to promote oil and gas flow, and the use of

nuclear explosions to cap oil gushers and extinguish

fires. It was reported that even more exotic applications, such as melting glaciers for irrigation, were

being considered by the Soviet Union.

The first test under the Plowshare Program,

‘‘Gnome,’ was conducted 4 years later to create an

underground cavity in a large salt deposit. The next

Plowshare experiment, Sedan in 1962, used a 104

kiloton explosion to excavate 12 million tons of

earth. In 1965, the concept of ‘nuclear excavation’

was refined and proposed as a means of building a

second canal through Panama.12 Three nuclear

excavations were tested under the Plowshare program ("Cabriolet,” Jan. 26, 1968; “Buggy,” Mar.

12, 1968; and “Schooner,” Dec. 12, 1968). Schooner, however, released radioactivity off site and, as

a consequence, no future crater test was approved.

Consideration of the radiological and logistical

aspects of the project also contributed to its demise,

Estimates of the engineering requirements indicated

that approximately 250 separate nuclear explosions

with a total yield of 120 megatons would be required

to excavate the canal through Panama. Furthermore,

fallout predictions indicated that 16,000 square

kilometers of territory would need to be evacuated

for the duration of the operation and several months

thereafter. 13 Because it was also clear that no level

of radioactivity would be publicly acceptable, the

program was terminated in the early 1970s.

In 1974, President Richard Nixon signed the

Threshold Test Ban Treaty (TTBT) restricting all

nuclear test explosions to a defined test site and to

yields no greater than 150 kilotons. As a result, all

U.S. underground nuclear tests since 1974 have been

conducted at the Nevada Test Site. As part of the

earlier 1963 Limited Test Ban Treaty, the United

States established a series of safeguards. One of

them, “Safeguard C,” requires the United States to

maintain the capability to resume atmospheric

testing in case the treaty is abrogated. The Department of Energy (DOE) and the Defense Nuclear

Agency continue today to maintain a facility for the

lzne 1956 war over he Suez Canal created the first specific proposals for using INICkSI explosions to create ~ dtemalive can~.

IsBruce A. Bolt, “Nuclear Explosions and Earthquakes, The Parted Veil” San Francisco, CA: W.H. Freeman& Co., 1976, pp. 192-1%.
14 ● The Containment of Underground Nuclear Explosions

Photo cradit: David Graham, 1988

Sedan Crater

atmospheric testing of nuclear weapons at the

Johnston Atoll in the Pacific Ocean.

LIMITS ON NUCLEAR TESTING

The testing of nuclear weapons by the United

States is currently restricted by three major treaties

that were developed for both environmental and

arms control reasons. The three treaties are:

1. the 1963 Limited Nuclear Test Ban Treaty,

which bans nuclear explosions in the atmosphere,

outer space, and underwater, and restricts the release

of radiation into the atmosphere,

2. the 1974 Threshold Test Ban Treaty, which

restricts the testing of underground nuclear weapons

by the United States and the Soviet Union to yields

no greater than 150 kilotons, and

3. the 1976 Peaceful Nuclear Explosions Treaty

(PNET), which is a complement to the Threshold

Test Ban Treaty (TTBT). It restricts individual

peaceful nuclear explosions (PNEs) by the United

States and the Soviet Union to yields no greater than

150 kilotons, and group explosions (consisting of a

number of individual explosions detonated simultaneously) to aggregate yields no greater than 1,500

kilotons.

Although both the 1974 TTBT and the 1976

PNET remain unratified, both the United States and

the Soviet Union have expressed their intent to abide

by the yield limit. Because neither country has

indicated an intention not to ratify the treaties, both

parties are obligated to refrain from any acts that

would defeat their objective and purpose. 14 Consequently, all nuclear test explosions compliant with

treaty obligations must be conducted underground,

at specific test sites (unless a PNE), and with yields

no greater than 150 kilotons. The test must also be

contained to the extent that no radioactive debris is

detected outside the territorial limits of the country

that conducted the test. 15 Provisions do exist,

however, for one or two slight, unintentional breaches

per year of the 150 kiloton limit due to the technical

uncertainties associated with predicting the exact

yields of nuclear weapons tests.l6

14~e 18, 1969 Vienna convention on tie Law of Tre~ies,

15~. I, l(b), 1963 Limited lkst Ban Treaty.

lbs[~ment of llndel-st~ding included with the transmittal documents accompanying the Threshold Test BarI Treaty and the Peaceful Nuclear

Explosions Treaty when submitted to the Senate for advice and consent to ratification on July 29, 1979.
Chapter 2—The Nuclear Testing Program . 15

OTHER LOCATIONS OF

NUCLEAR TESTS

U.S. nuclear test explosions were also conducted

in areas other than the Pacific and the Nevada Test

Site.

Three tests with yields of 1 to 2 kilotons were

conducted over the South Atlantic as ‘‘Operation

Argus.’ ‘ The tests (“Argus I,” Aug. 27, 1958;

“Argus H,” Aug. 30, 1958; and “Argus III,” Sept.

6, 1958) were detonated at an altitude of 300 miles

to assess the effects of high-altitude nuclear detonations on communications equipment and missile

performance.

Five tests, all involving chemical explosions but

with no nuclear yield, were conducted at the Nevada

Bombing Range to study plutonium dispersal. The

tests, “Project 57 NO l,” April 24, 1957; “Double

Tracks,” May 15, 1963; “Clean Slate I,” May 25,

1963; “Clean Slate II,” May 31, 1963; and “Clean

Slate III,’ June 9, 1963; were safety tests to establish

storage and transportation requirements.

Two tests were conducted in the Tatum Salt Dome

near Hattiesburg, Mississippi, as part of the Vela

Uniform experiments to improve seismic methods of

detecting underground nuclear explosions. The first

test ‘Salmon,’ October 22, 1964, was a 5.3 kiloton

explosion that formed an underground cavity. The

subsequent test “Sterling,” December 3, 1966, was

0.38 kt explosion detonated in the cavity formed by

Salmon. The purpose of the Salmon/Sterling experiment was to assess the use of a cavity in reducing the

size of seismic signals produced by an underground

nuclear test.17

Three joint government-industry tests were conducted as part of the Plowshare Program to develop

peaceful uses of nuclear explosions. The experiments were designed to improve natural gas extraction by fracturing rock formations. The first test,

‘‘Gasbuggy,’ was a 29 kiloton explosion detonated

on December 10, 1967, near Bloomfield, New

Mexico. The next two were in Colorado: “Rulison”

was a 40 kiloton explosion, detonated near Grand

Valley on September 10, 1969; and “Rio Blanco”

was a salvo shot of three explosions, each with a

yield of 33 kt, detonated near Rifle on May 17, 1973.

Three tests were conducted on Amchitka Island,

Alaska. The first (October 29, 1965), “Long Shot”

was an 80 kiloton explosion that was part of the Vela

Uniform project. The second test, “Milrow," October 2, 1969, was about a one megaton explosion to

‘‘calibrate’ the island and assure that it would

contain a subsequent test of the Spartan AntiBallistic Missile warhead. The third test, “Cannikin,” November 6, 1971, was the Spartan warhead

test with a reported yield of “less than five

megatons. This test, by far the highest-yield

underground test ever conducted by the United

States, was too large to be safely conducted in

Nevada. 18

Three individual tests were also conducted in

various parts of the western United States. “Gnome’

was a 3 kiloton test conducted on December 10,

1961 near Carlsbad, New Mexico, to create a large

underground cavity in salt as part of a multipurpose

experiment. One application was the possible use of

the cavity for the storage of oil and gas. “Shoal”

was a 12 kiloton test conducted on October 26, 1963

near Fallen, Nevada as part of the Vela Uniform

project. ‘‘Faultless” was a test with a yield of

between 200 and 1,000 kiloton that was exploded on

January 19, 1968, at a remote area near Hot Creek

Valley, Nevada. Faultless was a ground-motion

calibration test to evaluate a Central Nevada Supplemental Test Area. The area was proposed as a

alternative location for high-yield tests to decrease

the ground shaking in Las Vegas.

THE NEVADA TEST SITE

The Nevada Test Site is located 65 miles northwest of Las Vegas. It covers 1,350 square miles, art

area slightly larger than Rhode Island (figure 2-2).

The test site is surrounded on three sides by an

additional 4,000 to 5,000 square miles belonging to

Nellis Air Force Base and the Tonopah Test Range.

The test site has an administrative center, a control

point, and areas where various testing activities are

conducted.

At the southern end of the test site is Mercury, the

administrative headquarters and supply base for

17 For a complete ~scusslon of the issues related to Seismic Verification see, U.S. Congress, Office of ‘Ikchnology Assessment, sdSmlC ve@CafiOn

of Nuclear Testing Treaties, OTA-ISC-361, Washington, DC: U.S. Government Printing Office, May 1988.

ISW @ictions of ~md motion suggest~ hat ~ ~~ceptable mount (~ te~s of c]afis ~d dol]~s) of damage would OCCIM to structures if

the test was conducted in Nevada.
16 . The Containment of Underground Nuclear Explosions

Figure 2-2--Nevada Test Site

:

SOURCE: Modified from Department of Energy.

DOE contractors and other agencies involved in

Nevada Operations. Mercury contains a limited

amount of housing for test site personnel and other

ground support facilities.

Near the center of the test site, overlooking

Frenchman Flat to the South and Yucca Flat to the

North, is the Control Point (CP). The CP is the

command headquarters for testing activities and is

the location from which all tests are detonated and

monitored.

Frenchman Flat is the location of the first nuclear

test at the test site. A total of 14 atmospheric tests

occurred on Frenchman Flat between 1951 and

1962. Most of these tests were designed to determine

the effects of nuclear explosions on structures and

military objects. The area was chosen for its flat

terrain which permitted good photography of detonations and fireballs. Also, 10 tests were conducted

underground at Frenchman Flat between 1965 and

1971. Frenchman Flat is no longer used as a location

for testing. The presence of carbonate material

makes the area less suitable for underground testing

than other locations on the test site.19

Yucca Flat is where most underground tests occur

today. These tests are conducted in vertical drill

holes up to 10 feet in diameter and from 600 ft to

more than 1 mile deep. It is a valley 10 by 20 miles

extending north from the CP. Tests up to about 300

kilotons in yield have been detonated beneath Yucca

1$’~ng ~ explmion, cti~nate material can form carbon dioxide which, under pressure, can cause venting.
Chapter 2—The Nuclear Testing Program . 17

PfWO Crti”t” Dan”d Graham, Ig&7

Test Debris on Frenchman Flat

Flat, although Pahute Mesa is now generally reserved for high-yield tests.

Tests up to 1,000 kilotons in yield have occurred

beneath Pahute Mesa, a 170 square mile area in the

extreme north-western part of the test site. The deep

water table of Pahute Mesa permits underground

testing in dry holes at depths as great as 2,100 feet.

The distant location is useful for high-yield tests

because it minimizes the chance that ground motion

will cause damage offsite.

Both Livermore National Laboratory and Los

Alamos National Laboratory have specific areas of

the test site reserved for their use. Los Alamos uses

areas 1, 3, 4 (east), 5, and 7 in Yucca Flat and area 19

on Pahute Mesa; Livermore uses areas 2, 4 (west), 8,

9, and 10 in Yucca Flat, and area 20 on Pahute Mesa

(figure 2-2). While Los Alamos generally uses

Pahute Mesa only to relieve schedule conflicts on

Yucca Flat, Livermore normally uses it for large test

explosions where the depth of burial would require

the test to be below the water table on Yucca Flat.

The Nevada Test Site employs over 11,000

people, with about 5,0(K) of them working on the site

proper. The annual budget is approximately $1

billion divided among testing nuclear weapons

(81%) and the development of a storage facility for

radioactive waste (19%). The major contractors are

Reynolds Electrical &Engineering Co., Inc. (REECo),
Edgerton, Germeshausen & Greer (EG&G), Fenix &

Scisson, Inc., and Holmes& Narver, Inc. REECo has

5,000 employees at the test site for construction,

maintenance, and operational support, which includes large diameter drilling and tunneling, on-site

radiation monitoring, and operation of base camps.

EG&G has 2,200 employees, who design, fabricate,

and operate the diagnostic and scientific equipment.

Fenix & Scisson, Inc. handles the design, research,

inspection, and procurement for the drilling and

mining activities. Holmes & Narver, Inc. has responsibility for architectural design, engineering design,

and inspection. In addition to contractors, several

government agencies provide support to the testing

program: the Environmental Protection Agency

(EPA) has responsibility for radiation monitoring

outside the Nevada Test Site; the National Oceanic

and Atmospheric Administration (NOAA) provides

weather analyses and predictions; and the United

States Geological Survey (USGS) provides geological, geophysical, and hydrological assessments of

test locations.

TYPES OF NUCLEAR TESTS

Presently, an average of more than 12 tests per

year are conducted at the Nevada Test Site. Each test

is either at the bottom of a vertical drill hole or at the

end of a horizontal tunnel. The vertical drill hole

tests are the most common (representing over 90%

of all tests conducted) and occur either on Yucca Flat

or, if they are large-yield tests, on Pahute Mesa.

Most vertical drill hole tests are for the purpose of

developing new weapon systems. Horizontal tunnel

tests are more costly and time-consuming. They only

occur once or twice a year and are located in tunnels

mined in the Rainier and Aqueduct Mesas. Tunnel

tests are generally for evaluating the effects (radiation, ground shock, etc.) of various weapons on

military hardware and systems. In addition, the

United Kingdom also tests at a rate of about once a

year at the Nevada Test Site.

It takes 6 to 8 weeks to drill a hole depending on

depth and location. The holes used by Livermore and

Los Alamos differ slightly. Los Alamos typically

uses holes with diameters that range from about 4
Chapter 2—The Nuclear Testing Program ● 19

I%oto credir Department of Enetyy

Emplacement Tower for Vertical Drill Hole Test

1/2 up to 7 ft; while Livermore typically uses 8-ft

diameter holes and an occasional 10-ft diameter

hole. 20 Livermore usually places its experimental

devices above the water table to avoid the additional

time and expense required to case holes below the

water table.

When the device is detonated at the bottom of a

vertical drill hole, data from the test are transmitted

through electrical and fiber-optic cables to trailers

containing recording equipment. Performance information is also determined from samples of radioactive material that are recovered by drilling back into

the solidified melt created by the explosion (figure

2-3). On rare occasions, vertical drill holes have

been used for effects tests. One such test, “Huron

King,” used an initially open, vertical “line-ofsight" pipe that extended upwards to a large

Figure 2-3-Drill-Back operation

SOURCE: Modified from Michael W. Butler, PasfstIcIt Dri//ing Handbook,

Lawrence Livermore National Laboratory, Jan. 19, 1984.

enclosed chamber located at the surface. The chamber contained a satellite inside a vacuum to simulate

the conditions of space. The radiation from the

explosion was directed up the hole at the satellite.

The explosion was contained by a series of mechanical pipe closures that blocked the pipe immediately

after the initial burst of radiation. The purpose of the

test was to determine how satellites might be

affected by the radiation produced by a nuclear

explosion.

Tunnel tests occur within horizontal tunnels that

are drilled into the volcanic rock of Rainier or

Aqueduct Mesa. From 1970 through 1988, there

. . .

20Llve~~ has c~si&red the U,W of 12 ft diameter holes, but has not yet @ One.
20 ● The Containment of Underground Nuclear Explosions

Huron King Test

have been 31 tunnel tests conducted in Rainier and

Aqueduct Mesas (figure 2-4). It may require 12

months of mining, using three shifts a day, to remove

the 1 million cubic feet of rock that may be needed

to prepare for a tunnel test.

Effects tests performed within mined tunnels are

designed to determine the effects of nuclear explosionproduced radiation on missile nose cones, warheads,

satellites, communications equipment, and other

military hardware. The tunnels are large enough so

that satellites can be tested at full scale in vacuum

chambers that simulate outer space. The tests are

used to determine how weapons systems will

withstand radiation that might be produced by a

nearby explosion during a nuclear war. Nuclear

effects tests were the first type of experiments

performed during trials in the Pacific and were an

extensive part of the testing program in the 1950s. At

that time, many tests occurred above ground and

included the study of effects on structures and civil

defense systems.

Effects tests within cavities provide a means of

simulating surface explosions underground. A large

hemispherical cavity is excavated and an explosion

is detonated on or near the floor of the cavity. The

tests are designed to assess the capability of aboveground explosions to transmit energy into the

ground. This information is used to evaluate the

capability of nuclear weapons to destroy such targets

as missile silos or underground command centers.
Chapter 2—The Nuclear Testing Program ● 21

Figure 2-4--Locations of Tunnel Tests In Rainier and Aqueduct Mesas

Topographic

of Mesa

SOURCE: Modified from Defense Nuclear Agency

ANNOUNCEMENT OF

NUCLEAR TESTS

The existence of each nuclear test conducted prior

to the signing of the LTBT on August 5, 1963, has

been declassified. Many tests conducted since the

signing of the LTBT, however, have not been

announced. Information concerning those tests is

classified. The yields of announced tests are presently reported only in the general categories of either

less than 20 kilotons, or 20 to 150 kilotons. The

DOE’s announcement policy is that a test will be

pre-announced in the afternoon 2 days before the test

if it is determined that the maximum credible yield

is such that it could result in perceptible ground

motion in Las Vegas. The test will be post announced if there is a prompt release of radioactive

material or if any late-time release results in
22 ● The Containment of Underground Nuclear Explosions

-.

Photo cradit: Datid Graham, 1968

Tunnel Entrance

radioactive material being detected off the test site.

In the case of late-time release, however, the test will

be announced only if radioactive material is detected off-site.

Starting with Trinity, names have been assigned

to all nuclear tests. The actual nuclear weapon or

device and its description are classified. Consequently, test planners assign innocuous code words

or nicknames so that they may refer to planned tests.

Early tests used the military phonetic alphabet

(Able, Baker, Charlie, etc.). As more tests took

place, other names were needed. They include

names of rivers, mountains, famous scientists, small

mammals, counties and towns, fish, birds, vehicles,

cocktails, automobiles, trees, cheeses, wines, fabrics, tools, nautical terms, colors, and so forth.

DETONATION AUTHORITY AND

PROCEDURE

The testing of nuclear weapons occurs under the

authority of the Atomic Energy Act of 1946 (as

amended in 1954), which states:

“The development, use, and control of Atomic

Energy shall be directed so as to make the maximum

contribution to the general welfare, subject at all

times to the paramount objective of making the

maximum contribution to the common defense and

security. ’

The act authorizes the U.S. Atomic Energy

Commission (now Department of Energy), to "con-

24 ● The Containment of Underground Nuclear Explosions

Photo credit: Defense Nuclear Agency

End of Tunnel

comments in its recommendation letter to the inventory to see if a suitable hole is available or if a

President. The Nevada Operations Office plans the new one must be drilled.

individual tests with the responsible laboratory. Once a hole is selected, the sponsoring laboratory

designs a plan to fill-in (or “stem”) the hole to

Both Livermore and Los Alamos maintain stock- contain the radioactive material produced by the

piles of holes in various areas of the test site.21 When explosion. The USGS and Earth scientists from

a specific test is proposed, the lab will check its several organizations analyze the geology surroundzlE~h ]a~ra~~ o~rates its own drilling crews continuously to maximim the economy of the drilling OpWiltion.
Chapter 2—The Nuclear Testing Program ● 25

ZZW Ch. 3, ‘‘Containment Evaluation Panel.

23~ nuclew ~ety study prepared by DOE Safety Division cont~s safety considerations not re]a(~ to containment, s~h as tie possibility of

premature or inadvertent detonation.

Mh ~c ~= of tesB sWnWr~ by tie Defense Nuclear Agency (DNA), the Scientific Advisor is from Smdla National Labor~ory.
26 ● The Containment of Underground Nuclear Explosions

from the sponsoring Laboratory.24 The three members are all knowledgeable about the weaponstesting program and consist of:

1. an EPA senior scientist with expertise in

radiation monitoring,

2. a weather service senior scientist knowledgeable in meteorology, and

3. a medical doctor with expertise in radiation

medicine.

Once the test has been approved for execution by the

Test Controller’s panel, the Test Controller has sole

responsibility to determine when or whether the test

will be conducted. The Test Controller and Advisory

Panel members conduct the following series of

technical meetings to review the test:25

D-7 Safety Planning Meeting: The “D-7 Safety

Planning Meeting” is held approximately 1 week

before the test. This meeting is an informal review

of the test procedure, the containment plan, the

expected yield, the maximum credible yield, the

potential for surface collapse, the potential ground

shock, the expected long-range weather conditions,

the location of radiation monitors, the location of all

personnel, the security concerns (including the

possibility of protesters intruding on the test site),

the countdown, the pre-announcement policy, and

any other operational or safety aspects related to the

test.

D-1 Safety Planning Meeting: The day before the

test, the D-1 Safety Planning Meeting is held. This

is an informal briefing that reviews and updates all

the information discussed at the D-7 meeting.

D-1 Containment Briefing: The D-1 Containment

Briefing is a formal meeting. The laboratory reviews

again the containment plan and discusses whether all

of the stemming and other containment requirements were met. The meeting determines the extent

to which the proposed containment plan was carried

out in the field.26 The laboratory and contractors

provide written statements on their concurrence of

the stemming plan.

D-1 Readiness Briefing: The D-1 Readiness

Briefing is a formal meeting to review potential

weather conditions and the predicted radiation

fallout pattern for the case of an accidental venting.

The night before the test, the weather service

sends out observers to release weather balloons and

begin measuring wind direction and speed to a

height of 1,400 ft above the ground. The area around

the test (usually all areas north of the Control Point

complex) is closed to all nonessential personnel. The

Environmental Protection Agency deploys monitoring personnel off-site to monitor fallout and coordinate protective measures, should they be necessary.

D-Day Readiness Briefing: The morning of the

test, the Test Controller holds the “D-Day Readiness Briefing. ’ At this meeting, updates of weather

conditions and forecasts are presented. In addition,

the weather service reviews the wind and stability

measurements to make final revisions to the fallout

pattern in the event of an accidental venting. The

fallout pattern is used to project exposure rates

throughout the potential affected area. The exposure

rates are calculated using the standard radiological

models of whole-body exposure and infant thyroid

dose from a family using milk cows in the fallout

region. The status of on-site ground-based and

airborne radiation monitoring is reviewed. The

location of EPA monitoring personnel is adjusted to

the projected fallout pattern, and the location of all

personnel on the test site is confined. At the end of

the meeting, the Scientific Advisor who is chairman

of the Test Controller’s Advisory Panel makes a

recommendation to the Test Controller to proceed or

delay.

If the decision is made to proceed, the Test

Controller gives permission for the nuclear device to

be armed. The operation of all radiation monitors,

readiness of aircraft, location of EPA personnel, etc.,

are confined. If the status remains favorable and the

weather conditions are acceptable, the Test Controller gives permission to start the countdown and to

fire. If nothing abnormal occurs, the countdown

proceeds to detonation. If a delay occurs, the

appropriate preparatory meetings are repeated.

zd~ tie c= of ~s~ sponsor~ by tie Defense Nuclear Agency (DNA), the Scientific Advisor is from Sandia National Laboratory.

2S~~ou@ @ tc~ h~ ~n prcp~atlons inclu~ provisions for ~ ~id~t~ release of radioactive materiat, Sucl

provisions include the deployment of an emergency response team for each test.

?6For Cxmp]e, ~~ngs from temperat~e sensors placed in the stemming plugs are examined to dete~ine whe~er tie Plugs have h~d~~.
Chapter 2—The Nuclear Testing Program ● 27

Photo credit: Department of Energy

Test Control Center
Chapter 3

Containing Underground

Nuclear Explosions
CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

WHAT HAPPENS DURING AN UNDERGROUND NUCLEAR

Microseconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Milliseconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +. . . . . . . . . . . . . . . . .

Tenths of a Second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A Few Seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minutes to Days . . . . . . . . . . . . . . . . . . .. .. .. .. .. .. .. ... ........

EXPLOSION 

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .

WHY NUCLEAR EXPLOSIONS REMAIN CONTAINED ... ...... . . . . . . . . . . . . . . . .

SELECTING LOCATION, DEPTH, AND SPACING: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REVIEWING A TEST SITE LOCATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTAINMENT EVALUATION PANEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTAINING VERTICAL SHAFT TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTAINING HORIZONTAL TUNNEL TESTS . . . . . . . . . . .. .. .. .. .. .. ... ... ......

TYPES OF RADIATION RELEASES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Containment Failure: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Late-Time Seep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Controlled Tunnel Purging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operational Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

RECORD OF CONTAINMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Containment Evaluation Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vertical Drill Hole ’lasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Horizontal Tunnel Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

From the Perspective of Human Health Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A FEW EXAMPLES: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

IS THERE A REAL ESTATE PROBLEM AT NTS? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TIRED MOUNTAIN SYNDROME? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HOW SAFE IS SAFE ENOUGH? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Box

3-A. Baneberry . . . . . . . . . . . . .

Figure

. . . .

3-1.

3-2.

3-3.

3-4.

3-5.

3-6.

3-7.

3-8.

3-9.

3-10.4

31

32

32

32

32

32

32

35

37

38

40

41

46

46

46

47

47

47

47

48

48

49

49

51

51

54

Page

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Figures

Page

Formation of Stress “Containment Cage” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minimum Shot Separation for Drill Hole Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minimum Shot Separation for Tunnel Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

“Typical’’ Stemming Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Three Redundant Containment Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vessel I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vessel 1 Closures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tunnel Closure Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Typical Post-Shot Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Radius of Decrease in Rock Strength . . . . . . . . . . . . . . . . . . . .. .. ... ... ....... . . . . .

35

38

39

41

42

43

44

45

46

53

Table Page

3-1. Release From Underground Tests . . . . . . . . . . . . . . . . . . . . .. .. .. . .. .. .. . . . .. .......8 48
Chapter 3

Containing Underground Nuclear Explosions

Underground nuclear tests are designed and reviewed for containment, with redundancy and

conservatism in each step.

INTRODUCTION

The United States’ first underground nuclear test,

codenamed ‘‘ Pascal-A,’ was detonated at the bottom of a 499-foot open drill-hole on July 26, 1957.1

Although Pascal-A marked the beginning of underground testing, above ground testing continued for

another 6 years. With testing simultaneously occurring aboveground, the release of radioactive material

from underground explosions was at first not a major

concern. Consequently, Pascal-A, like many of the

early underground tests that were to follow, was

conducted ‘‘reman candle’ style in an open shaft

that allowed venting.2

As public sensitivity to fallout increased, guidelines for testing in Nevada became more stringent. In

1956, the weapons laboratories pursued efforts to

reduce fallout by using the lowest possible test

yields, by applying reduced fission yield or clean

technology, and by containing explosions underground. Of these approaches, only underground

testing offered hope for eliminating fallout. The

objective was to contain the radioactive material, yet

still collect all required information. The first

experiment designed to contain an explosion completely underground was the “Rainier” test, which

was detonated on September 19, 1957. A nuclear

device with a known yield of 1.7 kilotons was

selected for the test. The test was designed with two

objectives: 1) to prevent the release of radioactivity

to the atmosphere, and 2) to determine whether

diagnostic information could be obtained from an

underground test. The test was successful in both

objectives. Five more tests were conducted the

following year to confirm the adequacy of such

testing for nuclear weapons development.

In November 1958, public concern over radioactive fallout brought about a nuclear testing moratorium that lasted nearly 3 years. After the United

States resumed testing in September, 1961, almost

all testing in Nevada was done underground, while

atmospheric testing was conducted in the Christmas

Island and Johnston Island area of the Pacific. From

1961 through 1963, many of the underground tests

vented radioactive material. The amounts were

small, however, in comparison to releases from

aboveground testing also occurring at that time.

With the success of the Rainier test, efforts were

made to understand the basic phenomenology of

contained underground explosions. Field efforts

included tunneling into the radioactive zone, laboratory measurements, and theoretical work to model

the containment process. Through additional tests,

experience was gained in tunnel-stemming processes and the effects of changing yields. The early

attempts to explain the physical reason why underground nuclear explosions do not always fracture

rock to the surface did little more than postulate the

hypothetical existence of a “mystical magical membrane.” In fact, it took more than a decade of

underground testing before theories for the physical

basis for containment were developed.

In 1963, U.S. atmospheric testing ended when the

United States signed the Limited Test Ban Treaty

prohibiting nuclear test explosions in any environment other than underground. The treaty also

prohibits any explosion that:

. . . causes radioactive debris to be present outside

the territorial limits of the State under whose

jurisdiction or control such explosion is conducted.3

With the venting of radioactive debris from

underground explosions restricted by treaty, containment techniques improved. Although many U.S.

tests continued to produce accidental releases of

radioactive material, most releases were only detectable within the boundaries of the Nevada Test Site.

In 1970, however, a test codenamed ‘‘Baneberry’

resulted in a prompt, massive venting. Radioactive

material from Baneberry was tracked as far as the

Canadian border and focused concern about both the

environmental safety and the treaty compliance of

IThc first underground icst wm the Uni[cd Slates’ 1 Wth nIJdeM explosion.

211 is intere5t1ng [.no(c tha[ even with ~open shaft, 90% of the fission products created by Pascal-A were contained Underground

3A~iClc I, I (b). 1963 Limited Test Ban Trcaly

-3 l–
32 ● The Containment of Underground Nuclear Explosions

the testing program. 4 Testing was suspended for 7

months while a detailed examination of testing

practices was conducted by the Atomic Energy

Commission. The examination resulted in new

testing procedures and specific recommendations

for review of test containment. The procedures

initiated as a consequence of Baneberry are the basis

of present-day testing practices.

Today, safety is an overriding concern throughout

every step in the planning and execution of an

underground nuclear test. Underground nuclear test

explosions are designed to be contained, reviewed

for containment, and conducted to minimize even

the most remote chance of an accidental release of

radioactive material. Each step of the testing authorization procedure is concerned with safety; and

conservatism and redundancy are built into the

system.5

WHAT HAPPENS DURING AN

UNDERGROUND NUCLEAR

EXPLOSION

The detonation of a nuclear explosion underground creates phenomena that occur within the

following time flames:

Microseconds

Within a microsecond (one-millionth of a second), the billions of atoms involved in a nuclear

explosion release their energy. Pressures within the

exploding nuclear weapon reach several million

pounds per square inch; and temperatures are as high

as 100 million degrees Centigrade. A strong shock

wave is created by the explosion and moves outward

from the point of detonation.

Milliseconds

Within tens of milliseconds (thousandths of a

second), the metal canister and surrounding rock are

vaporized, creating a bubble of high pressure steam

and gas. A cavity is then formed both by the pressure

of the gas bubble and by the explosive momentum

imparted to the surrounding rock,

Tenths of a Second

As the cavity continues to expand, the internal

pressure decreases. Within a few tenths of a second,

the pressure has dropped to a level roughly comparable to the weight of the overlying rock. At this point,

the cavity has reached its largest size and can no

longer grow.6 Meanwhile, the shockwave created by

the explosion has traveled outward from the cavity,

crushing and fracturing rock. Eventually, the shock

wave weakens to the point where the rock is no

longer crushed, but is merely compressed and then

returns to its original state. This compression and

relaxation phase becomes seismic waves that travel

through the Earth in the same manner as seismic

waves formed by an earthquake.

A Few Seconds

After a few seconds, the molten rock begins to

collect and solidify in a puddle at the bottom of the

cavity.7 Eventually, cooling causes the gas pressure

within the cavity to decrease.

Minutes to Days

When the gas pressure in the cavity declines to the

point where it is no longer able to support the

overlying rock, the cavity may collapse. The collapse occurs as overlying rock breaks into rubble and

falls into the cavity void. As the process continues,

the void region moves upward as rubble falls

downward. The “chimneying” continues until:

. the void volume within the chimney completely

fills with loose rubble,

. the chimney reaches a level where the shape of

the void region and the strength of the rock can

support the overburden material. or

. the chimney reaches the surface.

If the chimney reaches the surface, the ground sinks

forming a saucer-like subsidence crater. Cavity

collapse and chimney formation typically occur

within a few hours of the detonation but sometimes

take days or months.

4!kc for ex~p]e, Bruce A. Bolt, Nuclear Explosions and Eart@akes San Francisco, CA. (W.H. Freeman k CO., 1976).

~S= ‘ ~~tonatim &~ority and Procedures’ (ch. 2).

%x the next section, “How explosions remain contained, ” for a detailed explanation of cavity formation.

7~C So]idlfjed r~k cont~ns most of tie radioa~[ive products from the explosion. The performance Of the nUC@ weapon is ~~Y~~ when s~Plcs

of this material are recovered by drilling back into the cavity.
Chapter 3--Containing Underground Nuclear Explosions ● 33

Box 3-A—Baneberry

The exact cause of the 1970 Baneberry venting still remains a mystery. The original explanation postulated

the existence of an undetected water table. It 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, a buried scarp of hard rock, and a nearby

fault. It is thought that the weak, water-saturated clay was unable to support the containment structure: the hard scarp

strongly reflected back the energy of the explosion increasing its force; and the nearby fault provided a pathway

that gases could travel along. All three of these features seem to have contributed to the venting. Whatever its cause,

the Baneberry venting increased attention on containment and, in doing SO, marked the beginning of the present-day

containment practices.
34 ● The Containment of Underground Nuclear Explosions

Photo credit Harold E. Edgerton

Early phase of fireball from nuclear explosion.

WHY NUCLEAR EXPLOSIONS

REMAIN CONTAINED

Radioactive material produced by a nuclear explosion remains underground due to the combined

efforts of:

● the sealing nature of compressed rock around

the cavity,

. the porosity of the rock,

● the depth of burial,

● the strength of the rock, and

● the stemming of the emplacement hole.

Counter to intuition, only minimal rock

strength is required for containment.

At first, the explosion creates a pressurized cavity

filled with gas that is mostly steam. As the cavity

pushes outward, the surrounding rock is compressed

(figure 3-l(a)). Because there is essentially a fixed

quantity of gas within the cavity, the pressure

decreases as the cavity expands. Eventually the

pressure drops below the level required to deform

the surrounding material (figure 3-l(b)). Meanwhile, the shock wave has imparted outward motion

to the material around the cavity. Once the shock

wave has passed, however, the material tries to

return (rebound) to its original position (figure

3-l(c)). The rebound creates a large compressive

stress field, called a stress “containment cage’

around the cavity (figure 3-1 (d)). The physics of the

stress containment cage is somewhat analogous to

how stone archways support themselves. In the case

of a stone archway, the weight of each stone pushes

against the others and supports the archway. In the

case of an underground explosion, the rebounded

rock locks around the cavity forming a stress field

that is stronger than the pressure inside the cavity.

The stress “containment cage” closes any fractures

that may have begun and prevents new fractures

from forming.

The predominantly steam-filled cavity eventually

collapses forming a chimney. When collapse occurs,

the steam in the cavity is condensed through contact

with the cold rock falling into the cavity. The

noncondensible gases remain within the lower

chimney at low pressure. Once collapse occurs,

high-pressure steam is no longer present to drive

gases from the cavity region to the surface.

If the testis conducted in porous material, such as

alluvium or tuff, the porosity of the medium will

provide volume to absorb gases produced by the

explosion. For example, all of the steam generated

by a 150 kiloton explosion beneath the water table

can be contained in a condensed state within the

volume of pore space that exists in a hemispherical

pile of alluvium 200 to 300 feet high. Although most

steam condenses before leaving the cavity region,

the porosity helps to contain noncondensible gases

such as carbon dioxide (CO2

) and hydrogen (H2).

The gas diffuses into the interconnected pore space

and the pressure is reduced to a level that is too low

to drive the fractures. The deep water table and high

porosity of rocks at the Nevada Test Site facilitate

containment.

Containment also occurs because of the pressure

of overlying rock. The depth of burial provides a

stress that limits fracture growth. For example, as a

fracture initiated from the cavity grows, gas seeps

from the fracture into the surrounding material.

Eventually, the pressure within the fracture decreases below what is needed to extend the fracture.

At this point, growth of the fracture stops and the gas

simply leaks into the surrounding material.

Rock strength is also an important aspect of

containment, but only in the sense that an extremely

weak rock (such as water-saturated clay) cannot
Chapter 3-Containing Underground Nuclear Explosions ● 35

A

1 ) Cavity expands outward and deforms surrounding rock. 2) Natural resistance to deformation stops expansion. 3) Cavity contracts

(rebounds) from elastic unloading of distant rock. 4) Rebound locks in compressive residual stress around cavity.

SOURCE: Modified from Lawrenee Lwermore National Laboratory.

support a stress containment cage. Detonation within

weak, saturated clay is thought to have been a factor

in the release of the Baneberry test. As a result, sites

containing large amounts of water-saturated clay are

now avoided.

The final aspect of containment is the stemming

that is put in a vertical hole after the nuclear device

has been emplaced. Stemming is designed to prevent

gas from traveling up the emplacement hole. Impermeable plugs, located at various distances along the

stemming column, force the gases into the surrounding rock where it is ‘‘sponged up’ in the pore spaces.

How the various containment features perform

depends on many variables: the size of the explosion, the depth of burial, the water content of the

rock, the geologic structure, etc. Problems may

occur when the containment cage does not form

completely and gas from the cavity flows either

through the emplacement hole or the overburden

material. 8 When the cavity collapses, the steam

condenses and only noncondensible gases such as

carbon dioxide (CO2

) and hydrogen (H2) remain in

the cavity.9 The CO2 and H2 remain in the chimney

if there is available pore space. If the quantity of

noncondensible gases is large, however, they can act

as a driving force to transport radioactivity through

the chimney or the overlying rock. Consequently,

the amount of carbonate material and water in the

rock near the explosion and the amount of iron

available for reaction are considered when evaluating containment.10

SELECTING LOCATION, DEPTH,

AND SPACING

The site for conducting a nuclear test is, at first,

selected only on a tentative basis. The final decision

is made after various site characteristics have been

reviewed. The location, depth of burial, and spacing

are based on the maximum expected yield for the

nuclear device, the required geometry of the test, and

the practical considerations of scheduling, convenience, and available holes. If none of the inventory

holes are suitable, a site is selected and a hole

drilled. 11

The first scale for determining how deep an

explosion should be buried was derived from the

Rainier test in 1957. The depth. based on the cube

root of the yield, was originally:

Depth = 300 (yield)1/3

where depth was measured in feet and yield in

ELWk of a ,qfess ‘‘containment cage’ may not be a serious problem if the medium is sufticently porous or if the depth of burial is suflicent.

‘Whe C02 is formed from the vaporization of carbonate material; while the Hz is formed when water reacts with the iron in the nuclear device and

diagnostics equipment.

l%~M~nate mate-id ~ F~enChm~ Flat created co2hat 15 thought to have caused a ~ep during the DiagOn~Line test (Nov. 24, 19’7 1 ). Diagonal

Line was the last test on Frenchman Flat; the area is currently considered impractical for underground testing largely because of the carbonate matcnal.

IISW. ch. 2, ‘ ‘The Nevada Tkst Site,” for a description of the areas each Laboratory uses for testing.
36 ● The Containment of Underground Nuclear Explosions

Photo credit: Department of Energy

Blanca containment failure, 1958.

kilotons. The first few tests after Rainier, however, thus became: 300 (yield)’/’ “plus-a-few-hundredwere detonated at greater depths than this formula feet.

requires because it was more convenient to mine

tunnels deeper in the Mesa. It was not until

‘‘ Blanca,’ October 30, 1958, that a test was

conducted exactly at 300 (yield) l/3 feet to test the

depth scale. The containment of the Blanca explosion, however, was unsuccessful and resulted in a

surface venting of radioactive material. As a consequence, the depth scale was modified to include the

addition of a few hundred feet as a safety factor and

Today, the general depth of burial can be approximated by the equation:

Depth = 400 (yield)’ /q,

where depth is measured in feet and yield in

kilotons. 12 The minimum depth of burial, however,

is 600 feet. 13 Consequently, depths of burial vary

from 600 feet for a low-yield device, to about 2,100

feet for a large-yield test. The depth is scaled to the

IZ’ ‘~b]ic Safety for Nuclear Weapons TCSIS, ” Unlmd States Environmental Protection Agency, January, 1984.

!sThe &)().fW[ dcp~ ~= chosen as a minimum after a stalisti~al study show~ that ~C likelihood of a seep of radioactive makrid K) the surface for

explosions buried 600 feet or more was about 1/2 as great as for explosions at less than 500 feet, even if they were buried at the same scale-depth in

eaeh case.
Chapter Containing Underground Nuclear Explosions ● 37

‘‘maximum credible yield’ that the nuclear device

is thought physically capable of producing, not to

the design yield or most likely yield. 14

Whether a test will be conducted on Pahute Mesa

or Yucca Flat depends on the maximum credible

yield. Yucca Flat is closer to support facilities and

therefore more convenient, while the deep water

table at Pahute Mesa is more economical for large

yield tests that need deep, large diameter emplacement holes. Large yield tests in small diameter holes

(less than 7 feet) can be conducted in Yucca Flat. A

test area may also be chosen to avoid scheduling

conflicts that might result in a test damaging the hole

or diagnostic equipment of another nearby test. Once

the area has been chosen, several candidate sites are

selected based on such features as: proximity to

previous tests or existing drill holes; geologic

features such as faults, depth to basement rock, and

the presence of clays or carbonate materials; and

practical considerations such as proximity to power

lines, roads, etc.

In areas well suited for testing, an additional site

selection restriction is the proximity to previous

tests. For vertical drill hole tests, the minimum shot

separation distance is about one-half the depth of

burial for the new shot (figure 3-2). For shallow

shots, this separation distance allows tests to be

spaced so close together that in some cases, the

surface collapse craters coalesce. The 1/2 depth of

burial distance is a convention of convenience,

rather than a criterion for containment.15 It is, for

example, difficult to safely place a drilling rig too

close to an existing collapse crater.

Horizontal tunnel tests are generally spaced with

a minimum shot separation distance of twice the

combined cavity radius plus 100 feet, measured

from the point of detonation (called the “working

point”) (figure 3-3). In other words, two tests with

100 foot radius cavities would be separated by 300

feet between cavities, or 500 feet (center to center).

The size of a cavity formed by an explosion is

proportional to the cube root of the yield and can be

estimated by:

Radius = 55 (yield) ’h,

where the radius is measured in feet and the yield in

kilotons. For example, an 8 kiloton explosion would

be expected to produce an underground cavity with

approximately a 110 foot radius. Two such test

explosions would require a minimum separation

distance of 320 feet between cavities or 540 feet

between working points.

Occasionally, a hole or tunnel is found to be

unsuitable for the proposed test. Such a situation,

however, is rare, occurring at a rate of about 1 out of

25 for a drill hole test and about 1 out of 15 for a

tunnel test. 16 Usually, a particular hole that is found

unacceptable for one test can be used for another test

at a lower yield.

REVIEWING A TEST SITE

LOCATION

Once the general parameters for a drill-hole have

been selected, the sponsoring laboratory requests a

pre-drill Geologic Data Summary (GDS) from the

U.S. Geological Survey. The GDS is a geologic

interpretation of the area that reviews the three basic

elements: the structures, the rock type, and the water

content. The U.S. Geological Survey looks for

features that have caused containment problems in

the past. Of particular concern is the presence of any

faults that might become pathways for the release of

radioactive material, and the close location of hard

basement rock that may reflect the energy created by

the explosion, Review of the rock type checks for

features such as clay content which would indicate

a weak area where it may be difficult for the hole to

remain intact, and the presence of carbonate rock

that could produce CO2

. Water content is also

reviewed to predict the amount of steam and H2 that

might be produced. If the geology indicates less than

ideal conditions, alternate locations may be suggested that vary from less than a few hundred feet

from the proposed site to an entirely different area of

the test site.

When the final site location is drilled, data are

collected and evaluated by the sponsoring laboratory. Samples and geophysical logs, including downhole photography, are collected and analyzed. The

U.S. Geological Survey reviews the data, consults

with the laboratory throughout the process, and

reviews the accuracy of the geologic interpretations.

IQk mmy cwws tie muimum credible yield is significantly larger than the expected yield for a nuclear device.

ISA.S di=uw~ ]aler, testing in previously fractured rock is not considered a containment risk in mOSt iM3WX.

1-~rw ~culon5 tuMe]5 have&n abandoned ~auw of un~[icipa[ed conditions such ~$ tie di~overy of a fau]t or the presence of too much

water,
38 ● The Containment of Underground Nuclear Explosions

Figure 3-2-Minimum Shot Separation for Drill Hole Tests

Yucca flats

Diagram to approximate scale

Scale illustration of the minimum separation distance (1/2 depth of burial) for vertical drill hole tests. The

depth of burial is based on the maximum credible yield.

SOURCE: Office of Technology Assessment, 1989

To confirm the accuracy of the geologic description

and review and evaluate containment considerations, the Survey also attends the host laboratory’s

site proposal presentation to the Containment Evaluation Panel.

CONTAINMENT EVALUATION

PANEL

One consequence of the Baneberry review was the

restructuring of what was then called the Test

Evaluation Panel. The panel was reorganized and

new members with a wider range of geologic and

hydrologic expertise were added. The new panel was

named the Containment Evaluation Panel (CEP);

and their first meeting was held in March, 1971.

The Containment Evaluation Panel presently

consists of a Chairman and up to 11 panel members.

Six of the panel members are representatives from

Lawrence Livermore National Laboratory, Los Alamos

National Laboratory, Defense Nuclear Agency, Sandia National Laboratory, U.S. Geological Survey,

and the Desert Research Institute. An additional 3 to

5 members are also included for their expertise in

disciplines related to containment. The chairman of

the panel is appointed by the Manager of Nevada

Operations (Department of Energy), and panel

members are nominated by the member institution

with the concurrence of the chairman and approval

of the Manager. The panel reports to the Manager of

Nevada Operations.

Practices of the Containment Evaluation Panel

have evolved throughout the past 18 years; however,

their purpose, as described by the Containment
Chapter Containing Underground Nuclear Explosions ● 39

Figure 3-3--Minimum Shot Separation for Tunnel Tests

Rainier Mesa

Tunnel tests are typically

overburied. Collapse chimneys

do not usually extend to surface.

I

Diagram to approximate scale

Scale illustration of the minimum separation distance (2 combined cavity radii plus 100 feet) for

horizontal tunnel tests. Tunnel tests are typically overburied. Collapse chimneys do not usually extend

to the surface.

SOURCE: Office of Technology Assessment, 1989

Evaluation Charter, remains specifically defined as 4. maintain a historical record of each evaluation

follows:17 and of the data, proceedings, and discussions

pertaining thereto.

1.

2.

3.

evaluate, as an independent organization reporting to the Manager of Nevada Operations,

the containment design of each proposed

nuclear test;

assure that all relevant data available for

proper evaluation are considered;

advise the manager of Nevada Operations of

the technical adequacy of such design from the

viewpoint of containment, thus providing the

manager a basis on which to request detonation authority; and

Although the CEP is charged with rendering a

judgment as to the adequacy of the design of the

containment, the panel does not vote. Each member

provides his independent judgment as to the prospect of containment, usually addressing his own area

of expertise but free to comment on any aspect of the

test. The Chairman is in charge of summarizing

these statements in a recommendation to the manager on whether to proceed with the test, based only

on the containment aspects. Containment Evaluation Panel guidelines instruct members to make their

judgments in such a way that:

17 Cont~ent Ev~u~ti~n ~~er, June 1, 1986, s~ti~n II.
40 ● The Containment of Underground Nuclear Explosions

Considerations of cost, schedules, and test objectives

shall not enter into the review of the technical

adequacy of any test from the viewpoint of containment. 18

Along with their judgments on containment, each

panel member evaluates the probability of containment using the following four categories: 19

1.

2.

3.

4.

Category A: Considering all containment features and appropriate historical, empirical, and

analytical data, the best judgment of the

member indicates a high confidence in successful containment as defined in VIII.F.

below.

Category B: Considering all containment features and appropriate historical, empirical, and

analytical data, the best judgment of the

member indicates a less, but still adequate,

degree of confidence in successful containment as defined in VIII.F. below.

Category C’: Considering all containment features and appropriate historical, empirical, and

analytical data, the best judgment of the

member indicates some doubt that successful

containment, as described in VIII.F. below,

will be achieved.

Unable to Categorize

Successful containment is defined for the CEP as:

. . . no radioactivity detectable off-site as measured

by normal monitoring equipment and no unanticipated release of activity on-site.

The Containment Evaluation Panel does not have

the direct authority to prevent a test from being

conducted. Their judgment, both as individuals and

as summarized by the Chairman, is presented to the

Manager. The Manager makes the decision as to

whether a Detonation Authority Request will be

made. The statements and categorization from each

CEP member are included as part of the permanent

Detonation Authority Request.

Although the panel only advises the Manager, it

would be unlikely for the Manager to request

detonation if the request included a judgment by the

CEP that the explosion might not be contained. The

record indicates the influence of the CEP. Since

formation of the panel in 1970, there has never been

a Detonation Authority Request submitted for approval with a containment plan that received a “C”

(“some doubt”) categorization from even one

member. 20 21

The Containment Evaluation Panel serves an

additional role in improving containment as a

consequence of their meetings. The discussions of

the CEP provide an ongoing forum for technical

discussions of containment concepts and practices.

As a consequence, general improvements to containment design have evolved through the panel discussions and debate.

CONTAINING VERTICAL

SHAFT TESTS

Once a hole has been selected and reviewed, a

stemming plan is made for the individual hole. The

stemming plan is usually formulated by adapting

previously successful stemming plans to the particularities of a given hole. The objective of the plan is

to prevent the emplacement hole from being the path

of least resistance for the flow of radioactive

material. In doing so, the stemming plan must take

into account the possibility of only a partial collapse:

if the chimney collapse extends only halfway to the

surface, the stemming above the collapse must

remain intact.

Lowering the nuclear device with the diagnostics

down the emplacement hole can take up to 5 days.

A typical test will have between 50 and 250

diagnostic cables with diameters as great as 15/~

inches packaged in bundles through the stemming

column. After the nuclear device is lowered into the

emplacement hole, the stemming is installed. Figure

3-4 shows a typical stemming plan for a Lawrence

18conta~ment Ev~~ion Pi ne] ch~r, June 1, 1986, Swtion 111-D.

lgcont~ent Ev~uation Panel Chaner, June 1, 1986, Section WI.

me grading system for containment plans has evolved since the early 1970’s. Prior to April, 1977, the Containment Evacuation Panel categorized

tests using the Roman numerals (I-IV) where 1-111 had about the same meaning as A-C and IV was a D which eventually was dropped as a letter and

just became ‘‘unable to categorize. ”

21 However, one shot (Mmdo) was submitted with an “unable to categorize” categorization, Mundo was a joint US-UK test conducted on May 1,

1984.
Chapter 3--Containing Underground Nuclear Explosions ● 41

Figure 3-4--"Typical” Stemming Plan

Plug

Typical stemming sequence of coarse material, fine material, and

sanded gypsum plug used by Lawrence Livermore National

Laboratory for vertical drill hole tests.

SOURCE: Modified from Lawrence Livermore National Laboratory.

Livermore test with six sanded gypsum concrete

plugs.22 The plugs have two purposes: 1) to impede

gas flow, and 2) to serve as structural platforms that

prevent the stemming from falling out if only a

partial collapse occurs. Under each plug is a layer of

sand-size fine material. The sand provides a base for

the plug. Alternating between the plugs and the

fines, coarse gravel is used to fill in the rest of the

stemming. The typical repeating pattern used for

stemming by Los Alamos, for example, is 50 feet of

gravel, 10 feet of sand, and a plug.

All the diagnostic cables from the nuclear device

are blocked to prevent gas from finding a pathway

through the cables and traveling to the surface. Cable

fan-out zones physically separate the cables at plugs

so that the grout and fines can seal between them.

Frequently, radiation detectors are installed between

plugs to monitor the post-shot flow of radiation

through the stemming column.

CONTAINING HORIZONTAL

TUNNEL TESTS

The containment of a horizontal tunnel test is

different from the containment of a vertical drill hole

test because the experimental apparatus is intended

to be recovered. In most tests, the objective is to

allow direct radiation from a nuclear explosion to

reach the experiment, but prevent the explosive

debris and fission products from destroying it.

Therefore, the containment is designed for two

tasks: 1 ) to prevent the uncontrolled release of

radioactive material into the atmosphere for public

safety, and 2) to prevent explosive debris from

reaching the experimental test chamber.

Both types of horizontal tunnel tests (effects tests

and cavity tests) use the same containment concept

of three redundant containment ‘‘vessels’ that nest

inside each other and are separated by plugs (figure

3-5).23 Each vessel is designed to independently

contain the nuclear explosion, even if the other

vessels fail. If, for example, gas leaks from vessel I

into vessel II, vessel II has a volume large enough so

that the resulting gas temperatures and pressures

would be well within the limits that the plugs are

designed to withstand. The vessels are organized as

follows:

Vessel I is designed to protect the experiment by

preventing damage to the equipment and allowing it

to be recovered.

Vessel II is designed to protect the tunnel system

so that it can be reused even if vessel I fails and the

experimental equipment is lost.

Vessel III is designed purely for containment,

such that even if the experimental equipment is lost

and the tunnel system contaminated, radioactive

material will not escape to the atmosphere.

In addition to the three containment vessels, there

is a gas seal door at the entrance of the tunnel system

that serves as an additional safety measure. The gas

seal door is closed prior to detonation and the area

&!A]though L;ve~Ore ~d ~~ ~amos ~~ [he WC gencr~ stemming philosophy, [here Me some differences: For example, Liver-more U.WS sandd

gypsum concrete plugs while Ims Alamos uses plugs made of epoxy. Also, Livermore uses an emplacement pipe for lowering the device downhole, while

Los Alarms lowers the device and diagnostic carmister on a wire rope harness.

ZSSW ch. 2 for a dixussion of types of nuc]ew tests.
42 ● The Containment of Underground Nuclear Explosions

Figure 3-5-Three Redundant Containment Vessels (Plan View)

Three containment vessels for the Mighty Oak Test conducted in the T-Tunnel Complex.

SOURCE: Modified from Defense Nuclear Agency.

between it and the vessel III plug is pressurized to

approximately 10 pounds per square inch.

The plugs that separate the vessels are constructed

of high strength grout or concrete 10 to 30 feet thick.

The sides of the vessel II plugs facing the working

point are constructed of steel. Vessel II plugs are

designed to withstand pressures up to 1,000 pounds

per square inch and temperatures up to 1,000 °F.

Vessel 111 plugs are constructed of massive concrete

and are designed to withstand pressures up to 500

pounds per square inch and temperatures up to 500

“F.

Before each test, the tunnel system is checked for

leaks. The entire system is closed off and pressurized

to 2 pounds per square inch with a gas containing

tracers in it. The surrounding area is then monitored

for the presence of the tracer gas. Frequently, the

chimney formed by the explosion is also subjected

to a post-shot pressurization test to ensure that no

radioactive material could leak through the chimney

to the surface.

The structure of vessel I, as shown in figure 3-6,

is designed to withstand the effects of ground shock

and contain the pressure, temperatures, and radiation

of the explosion. The nuclear explosive is located at

the working point, also known as the “zero room. ”

A long, tapered, horizontal line-of-sight (HLOS)

pipe extends 1,000 feet or more from the working

point to the test chamber where the experimental

equipment is located. The diameter of the pipe may

only be a few inches at the working point, but

typically increases to about 10 feet before it reaches
Chapter 3-Containing Underground Nuclear Explosions ● 43

Figure 3-6--Vessel I

Key: GSAC = gas seal auxiliary closure; MAC = modified auxiliary

closure; TAPS = Tunnel and pipe seal

The HLOS Vessel I is designed to protect the experimental

equipment after allowing radiation to travel down the pipe.

SOURCE: Modified from Defense Nuclear Agency.

the test chamber.24 The entire pipe is vacuum

pumped to simulate the conditions of space and to

minimize the attenuation of radiation. The bypass

drift (an access tunnel), located next to the line of

sight pipe, is created to provide access to the closures

and to different parts of the tunnel system. These

drifts allow for the nuclear device to be placed in the

zero room and for late-time emplacement of test

equipment. After the device has been emplaced at

the working point, the bypass drift is completely

filled with grout. After the experiment, parts of the

bypass drift will be reexcavated to permit access to

the tunnel system to recover the pipe and experimental equipment.

The area around the HLOS pipe is also filled with

grout, leaving only the HLOS pipe as a clear

pathway between the explosion and the test chamber. Near the explosion, grout with properties similar

to the surrounding rock is used so as not to interfere

with the formation of the stress containment cage.

Near the end of the pipe strong grout or concrete is

used to support the pipe and closures. In between,

the stemming is filled with super-lean grout designed to flow under moderate stress. The super-lean

grout is designed to fill in and effectively plug any

fractures that may form as the ground shock

collapses the pipe and creates a stemming plug.

As illustrated in figure 3-6, the principal components of an HLOS pipe system include a working

point room, a muffler, a modified auxiliary closure

(MAC), a gas seal auxiliary closure (GSAC), and a

tunnel and pipe seal (TAPS). All these closures are

installed primarily to protect the experimental equipment. The closures are designed to shut off the pipe

after the radiation created by the explosion has

traveled down to the test chamber, but before

material from the blast can fly down the pipe and

destroy the equipment.

The working point room is a box designed to

house the nuclear device. The muffler is an expanded region of the HLOS pipe that is designed to

reduce flow down the pipe by allowing expansion

and creating turbulence and stagnation. The MAC

(figure 3-7(a)) is a heavy steel housing that contains

two 12-inch-thick forged-aluminum doors designed

to close openings up to 84 inches in diameter. The

doors are installed opposite each other, perpendicular to the pipe. The doors are shut by high pressure

gas that is triggered at the time of detonation.

Although the doors close completely within 0.03

seconds (overlapping so that each door fills the

tunnel), in half that time they have met in the middle

and obscure the pipe. The GSAC is similar to the

MAC except that it is designed to provide a gas-tight

closure. The TAPS closure weighs 40 tons and the

design (figure 3-7(b)) resembles a large toilet seat,

The door, which weighs up to 9 tons, is hinged on the

top edge and held in the horizontal (open) position.

When the door is released, it swings down by gravity

and slams shut in about 0.75 seconds. Any pressure

remaining in the pipe pushes on the door making the

seal tighter. The MAC and GSAC will withstand

pressures up to 10,000 pounds per square inch. The

TAPS is designed to withstand pressures up to 1,000

pounds per square inch, and temperatures up to

1,000 ‘F.

When the explosion is detonated radiation travels

down the HLOS pipe at the speed of light, The

containment process (figure 3-8 (a-e), triggered at the

time of detonation, occurs in the following sequence

to protect experimental equipment and contain

radioactive material produced by the explosion:

. After 0.03 seconds (b), the cavity created by the

explosion expands and the shock wave moves

away from the working point and approaches

the MAC. The shock wave collapses the pipe,

squeezing it shut, and forms a stemming

“plug.’ Both the MAC and the GSAC shut off

zq~ ~cmlon, the di~cter of the pipe has inm-ca..ed 1020 feet.
44 ● The Containment of Underground Nuclear Explosions

Figure 3-7—Vessel I Closures

A)

Mechanical closures

(MAC/GSAC)

Pre-fire geometry

closure

(TAPS)

Approximate closed FAC geometry

Fast acting closure

(FAC)

A) Mechanical Closures (MAC/GSAC)

B) Tunnel and Pipe Seal (TAPS)

C) Fast Acting Closure (FAC)

SOURCE: Modified from Defense Nuclear Agency.

the pipe ahead of the shock wave to prevent enough to squeeze the pipe shut. The stemming

early flow of high-velocity gas and debris into plug stops forming at about the distance where

the experiment chamber. the first mechanical pipe closure is located.

● After 0.05 seconds (c), the ground shock moves . After 0.2 seconds (d), the cavity growth is

past the second closure and is no longer strong complete. The rebound from the explosion
Chapter 3--Containing Underground Nuclear Explosions ● 45

A) Zero Time: Explosion is detonated and the first two mechanical closures are fired. B) Within 0,03 seconds, a stemming plug is being

formed and mechanical pipe closure has occurred. C) Within 0.05 seconds, the stemming plug has formed. D) Within 0.2 seconds, cavity

growth is complete and a surrounding compressive residual stress field has formed, E) Within 0.75 seconds, closure is complete.

SOURCE. Modified from Defense Nuclear Agency.
46 ● The Containment of Underground Nuclear Explosions

locks in the residual stress field, thereby

forming a containment cage. The shock wave

passes the test chamber.

. After 0.75 seconds (e), the final mechanical seal

(TAPS) closes, preventing late-time explosive

and radioactive gases from entering the test

chamber.

The entire closure process for containment takes

less than 3/4 of a second. Because the tests are

typically buried at a depth greater than necessary for

containment, the chimney does not reach the surface

and a collapse crater normally does not form. A

typical post-shot chimney configuration with its

approximate boundaries is shown in figure 3-9.

In lower yield tests, such as those conducted in the

P-tunnel complex, the first mechanical closure is a

Fast Acting Closure (FAC) rather than a MAC.25

The FAC (figure 3-7(c)) closes in 0.001 seconds and

can withstand pressures of 30,000 pounds per square

inch. The FAC acts like a cork, blocking off the

HLOS pipe early, and preventing debris and stemming material from flying down the pipe. A similar

closure is currently being developed for larger yield

tunnel tests.

TYPES OF RADIATION RELEASES

Terms describing the release or containment of

underground nuclear explosions have been refined

to account for the volume of the material and the

conditions of the release. The commonly used terms

are described below.

Containment Failure

Containment failures are releases of radioactive

material that do not fall within the strict definition of

successful containment, which is described by the

Department of Energy as:

Containment such that a test results in no radioactivity detectable off site as measured by normal

monitoring equipment and no unanticipated release

of radioactivity onsite. Detection of noble gases that

appear onsite long after an event, due to changing

atmospheric conditions, is not unanticipated. Anticipated releases will be designed to conform to

specific guidance from DOE/HQ.26

Containment failures are commonly described as:

Approximate

chimney

boundary

n

. . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . .

Tunnel shots are typically overburied and the collapse chimney

rarely extends to the surface.

SOURCE: Modified from Defense Nuclear Agency.

Ventings

Ventings are prompt, massive, uncontrolled releases of radioactive material. They are characterized as active releases under pressure, such as when

radioactive material is driven out of the ground by

steam or gas. ‘‘ Baneberry,’ in 1970, is the last

example of an explosion that ‘‘vented. ”

Seeps

Seeps, which are not visible, can only be detected

by measuring for radiation. Seeps are characterized

as uncontrolled slow releases of radioactive material

with little or no energy.

Late-Time Seep

Late-time seeps are small releases of noncondensable gases that usually occur days or weeks after a

vertical drill hole test. The noncondensable gases

diffuse up through the pore spaces of the overlying

rock and are thought to be drawn to the surface by a

decrease in atmospheric pressure (called “atmospheric pumping”).

25~ p-t~e] complex is rnlned in Aqueduct Mesa ~d h~ ]ess overb~den (h~ the Nw.nnel complex in Rainier Mesa. Therefore, p-tUfIne] is

generally used for lower yield tests.

~Satlon VIII.F,Containrnen[ Evaluation Panel Charter.
Chapter 3--Containing Underground Nuclear Explosions ● 47

Photo credit: David Graham

Fast acting closure.

Controlled Tunnel Purging

Controlled tunnel purging is an intentional release

of radioactive material to recover experimental

equipment and ventilate test tunnels. During a

controlled tunnel purging, gases from the tunnel are

filtered, mixed with air to reduce the concentration,

and released over time when weather conditions are

favorable for dispersion into sparsely populated

areas.

Operational Release

Operational releases are small releases of radioactivity resulting from operational aspects of vertical

drill hole tests. Activities that often result in

operational releases include: drilling back down to

the location of the explosion to collect core samples

(called “drill back”), collecting gas samples from

the explosion (called “gas sampling’ “), and sealing

the drill back holes (called “cement back”)

RECORD OF CONTAINMENT

The containment of underground nuclear explosions is a process that has continually evolved

through learning, experimentation, and experience.

The record of containment illustrates the various

types of releases and their relative impact.

Containment Evaluation Panel

The Containment Evaluation Panel defines successful containment as no radioactivity detectable

offsite and no unanticipated release of activity

onsite. By this definition, the CEP has failed to

predict unsuccessful containment on four occasions

since 1970:
48 ● The Containment of Underground Nuclear Explosions

Camphor:

Diagonal Line:

Riola:

Agrini:

June 29, 1971, horizontal tunnel test,

less than 20 kilotons, radioactivity detected only on-site.

November 24, 1971, vertical shaft test,

less than 20 kilotons, radioactivity detected off-site.

September 25, 1980, vertical shaft test,

less than 20 kilotons, radioactivity detected off-site.

March 31, 1984, vertical shaft test, less

than 20 kilotons, radioactivity detected

only on-site.

These are the only tests (out of more than 200)

where radioactive material has been unintentionally

released to the atmosphere due to containment

failure. In only two of the cases was the radioactivity

detected outside the geographic boundary of the

Nevada Test Site.

There have, however, been several other instances

where conditions developed that were not expected.

For example, during the Midas Myth test on

February 15, 1984, an unexpected collapse crater

occurred above the test tunnel causing injuries to

personnel. In addition, the tunnel partially collapsed,

damaging experimental equipment. During the Mighty

Oak test on April 10, 1986, radioactive material

penetrated through two of the three containment

vessels. Experimental equipment worth $32 million

was destroyed and the tunnel system ventilation

required a large controlled release of radioactive

material (table 3-1). In the case of Midas Myth, no

radioactive material was released (in fact, all radioactive material was contained within vessel I). In the

case of Mighty Oak, the release of radioactive

material was intentional and controlled. Consequently, neither of these tests are considered containment failures by the CEP.

Vertical Drill Hole Tests

As discussed previously, vertical drill-hole tests

commonly use a stemming plan with six sanded

gypsum plugs or three epoxy plugs. Approximately

50 percent of the vertical drill hole tests show all

radiation being contained below the first plug, In

some cases, radiation above the plug may not signify

plug failure, but rather may indicate that radioactive

material has traveled through the medium around the

plug.

Table 3-1--Releases From Underground Wats

(normalized to 12 hours after event)

All releases 1971-1988:

Containment Failures:

Camphor, 1971 b

.. . . . . . . . . . . . . . . . . . . . . . .......360 Ci

Diagonal Line, 1971 . . . . . . . . . . . . . . . . . . ........6,800

Riola, 1980 . . . . . . . . . . . . . . . . . ................3,100

Agrini, 1984 . . . . . . . . . . . . . . . . .................. 690

Late-time Seeps:

Kappeli, 1984 . . . . . . . . . . . . . . . . .... . . .. .... .....12

Tierra, 1984 . . . . . . . . . . . . . . . . . .................600

Labquark, 1986 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Bodie, 19863 . . . . . . . . . . . . . . . . . . . . . . . . . . .. ......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, 1986 . . . . . . . . . . . . . . . . . ..........36,000

Mission Ghost, 1987 C . . . . . . . . . . . . . . . . . . . . .. ......3

Operational Releases:

108 tests from 1970-1988d . . . . . . . . . . . . . . . . . . . . .. 5,500

Total since Baneberry: 54,000 Ci

Major pre-1971 releases:

Platte, 1962, ., . . . . . . . . . . . . . . . . . . . . . .....1,900,000 Ci

Eel, 1962 . . . . . . . . . . . . . . . . . . . . ..........1,900,000

Des Moines, 1962 . . . . . . . . . . . . . . . . . .....11,000,000

Baneberry, 1970 . . . . . . . . . . . . . . . . . ........6,700,000

26 others from 1958-1970 . . . . . . . . . . . . ....3,800,000

Total: 25,300,000 Ci

Other Releases for Reference

NTS Atmospheric Testing 1951-1963: . .12,000,000,000 Ci

1 Kiloton Aboveground Explosion: . ........10,000,000

Chernobyl (estimate): . . . . ................81,000,000

aR+12 values apply only to containment failures, others are at time of

release.

bThe camphorfatlure includes 140 CI from tunnel PLJr9in9.

cBodie and Ms.slon Ghost also had drill-back releases.

dMany of these Operational releases are associated with tests that were not

announced.

SOURCE. OffIce of Technology Assessment, 1989.

All three of the vertical drill hole tests that

released radioactive material through containment

failure were low yield tests of less than 20 kilotons.

In general, the higher the yield, the less chance there

is that a vertical drill hole test will release radioactivity. 27

Horizontal Tunnel Tests

There have been no uncontrolled releases of

radioactive material detected offsite in the 31 tunnel

tests conducted since 1970. Furthermore, all but one

test, Mighty Oak, have allowed successful recovery

27H1@r yield te~t~ UC more ]ikc]y t. produ~c a c~n~ainrncnl Cage ~d result in the formation of a Co]lapse crater. AS discussed car]ier in this chapter

“why nuclear explosions remain contained, ’ such features contribute to the containment of the explosion.
Chapter 3--Containing Underground Nuclear Explosions ● 49

of the experimental equipment. Mighty Oak and

Camphor are the only tests where radioactivity

escaped out of vessel II. In no test, other than

Camphor, has radioactive material escaped out of

vessel III. Camphor resulted in an uncontrolled

release of radioactive material that was detected

only on site.

There have been several instances when small

amounts of radioactivity were released intentionally

to the atmosphere through controlled purging. In

these cases, the decision was made to vent the tunnel

and release the radioactivity so the experimental

results and equipment could be recovered. The

events that required such a controlled release are the

10 tests where radioactive material escaped out of

vessel I and into vessel II, namely:

Hybla Fair, October 28, 1974.

Hybla Gold, November 1, 1977.

Miners Iron, October 31, 1980.

Huron Landing, September 23, 1982.

Mini Jade, May 26, 1983.

Mill Yard, October 9, 1985.

Diamond Beech, October 9,

Misty Rain, April 6, 1985.

1985.

Mighty Oak, April 10, 1986.

Mission Ghost, June 20, 198728

In most cases, the release was due to the failure of

some part of the experiment protection system.

Table 3-1 includes every instance (for both

announced and unannounced tests) where radioactive material has reached the atmosphere under any

circumstances whatsoever from 1971 through 1988.

The lower part of table 3-1 summarizes underground

tests prior to 1971 and provides a comparison with

other releases of radioactive material.

Since 1970, 126 tests have resulted in radioactive

material reaching the atmosphere with a total release

of about 54,000 Curies. Of this amount, 11,500

Ci were due to containment failure and late-time

seeps. The remaining 42,500 Ci were operational

releases and controlled tunnel ventilations—with

Mighty Oak (36,000 Ci) as the main source. Section

3 of the table shows that the release of radioactive

material from underground nuclear testing since

Baneberry (54,000 Ci) is extremely small in comparison to the amount of material released by preBaneberry underground tests (25,300,000 Ci), the

early atmospheric tests at the Nevada Test Site, or

even the amount that would be released by a

l-kiloton explosion conducted above ground (l0,000,000

Ci).

From the Perspective of Human Health Risk

If a single person had been standing at the

boundary of the Nevada Test Site in the area of

maximum concentration of radioactivity for every

test since Baneberry (1970), that person’s total

exposure would be equivalent to 32 extra minutes

of normal background exposure (or the equivalent of 1/1000 of a single chest x-ray).

A FEW EXAMPLES:

Although over 90 percent of all test explosions

occur as predicted, occasionally something goes

wrong. In some cases, the failure results in the loss

of experimental equipment or requires the controlled

ventilation of a tunnel system. In even more rare

cases (less than 3 percent), the failure results in the

unintentional release of radioactive material to the

atmosphere. A look at examples shows situations

where an unexpected sequence of events contribute

to create an unpredicted situation (as occurred in

Baneberry (see box 3-l)), and also situations where

the full reason for containment failure still remains

a mystery.

1. Camphor (June 29, 1971, horizontal tunnel test,

less than 20 kilotons, radioactivity detected only

on-site, )

The ground shock produced by the Camphor

explosion failed to close the HLOS pipe fully. After

about 10 seconds, 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 passage ways and eroded open a hole.

Pressure was then placed on the final door, which

held but leaked slightly. Prior to the test, the

containment plan for Camphor received six ‘‘I’

from the CEP.29

zs~e Mission Ghost rc]e~ was due to a post-shol drill hole.

290p. cit., footnote 20.
50 ● The Containment of Underground Nuclear Explosions

2. Diagonal Line (November 24, 1971, vertical

shaft test, less than 20 kilotons, radioactivity detected off-site.)

In a sense, the Diagonal Line seep was predicted

by the CEP. Prior to the test, Diagonal Line received

all “A” categorizations, except from one member

who gave it a‘ ‘B. ’ ’30 It was a conclusion of the panel

that due to the high CO2 content, a late-time (hours

or days after detonation) seepage was a high

probability. They did not believe, however, that the

level of radiation would be high enough to be

detectable off-site. Permission to detonate was

requested and granted because the test objectives

were judged to outweigh the risk. 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. Diagonal Line was the last test detonated on

Frenchman Flat.

3. Riola (September 25, 1980, vertical shaft test,

less than 20 kilotons, radioactivity detected off-site.)

Ironically, Riola was originally proposed for a

different location. The Containment Evaluation

Panel, however, did not approve the first location

and so the test was moved. At its new location, Riola

was characterized by the CEP prior to the test with

8 “A”s. 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.

4. Agrini (March 31, 1984, vertical shaft test, less

than 20 kilotons, radioactivity detected only onsite. )

The Agrini explosion formed a deep subsidence

crater 60 feet west of the emplacement hole. A small

amount of radioactive material was pushed through

the chimney by noncondensible gas pressure and

was detected onsite. The containment plan for

Agrini received seven ‘‘A’ and two ‘B from the

CEP prior to the test. The ‘‘B’*s were due to the use

of a new stemming plan.

5. Midas Myth (February 15, 1984, horizontal

tunnel test, less than 20 kilotons, no release of

radioactive material.)

All of the radioactive material produced by the

Midas Myth test was contained within vessel I, with

no release of radioactivity to either the atmosphere

or the tunnel system. It is therefore not considered a

containment failure. Three hours after the test,

however, the cavity collapsed and the chimney

reached the surface forming an unanticipated subsidence crater. Equipment trailers were damaged and

personnel were injured (one person later died as a

result of complications from his injuries) when the

collapse crater formed.3

1 Analysis conducted after

the test indicated that the formation of the collapse

crater should have been expected. Shots conducted

on Yucca Flat with the same yield and at the same

depth of burial did, at times, produce surface

collapse craters. In the case of Midas Myth, collapse

was not predicted because there had never been a

collapse crater for a tunnel event and so the analysis

was not made prior to the accident. After analyzing

the test, the conclusion of the Surface Subsidence

Review Committee was:

That the crater is not an indication of some

unusual, anomalous occurrence specific to the U12T.04

emplacement site. Given the normal variation in

explosion phenomena, along with yield, depth of

burial, and geologic setting, experience indicates an

appreciable chance for the formation of a surface

subsidence crater for Midas Myth.

Prior to the test, the Containment Evaluation

Panel characterized Midas Myth with nine “A”s.

6. Misty Rain ( April 6, 1985, horizontal tunnel

test, less than 20 kilotons, no unintentional release of

radioactive material.)

Misty Rain is unusual in that it is the only tunnel

test since 1970 that did not have three containment

vessels. In the Misty Rain test, the decision was

made that because the tunnel system was so large, a

vessel II was not needed.32 Despite the lack of a

vessel II, the CEP categorized the containment of

Misty Rain with eight ‘A’ ‘s, and one ‘B. ’ ’33 During

the test, an early flow of energy down the HLOS pipe

prevented the complete closure of the MAC doors.

The MAC doors overlapped, but stopped a couple

inches short of full closure. The TAPS door closed

only 20 percent before the deformation from ground

shock prevented it from closing. A small amount of

30~1d3

sl~e injuries were due to the physical circumstances of the collapse. There was no rSdit3t-iOtI tXpOStM’C.

sz~e~fis in he tumel system created over 4 million cubic feet of open volume.

lis~e~~em~r did ~t i~[l~]y Categorize the test, ~terreceiving ~dition~ inf~ati~ concerning the test, he categorized the test with m ‘‘ A.
Chapter 3-Containing Underground Nuclear Explosions ● 51

radioactive material escaped down the pipe and then

seeped from the HLOS pipe tunnel into the bypass

tunnel. Subsequently, the tunnel was intentionally

vented so that experimental equipment could be

recovered.

7. Mighty Oak (April 10, 1986, horizontal tunnel

test, less than 20 kilotons, no unintentional release of

radioactive material.)

During the Mighty Oak test, the closure system

near the working point was over-pressured and

failed. The escaped pressure and temperature caused

both the MAC and the GSAC 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 pounds per square inch. After 50 seconds,

the center part (approximately 6 feet in diameter) of

the TAPS door broke through. With the closures

removed, the stemming column squeezed out

through the tunnel. Radioactive material leaked

from vessel I, into vessel II, and into vessel III, where

it was successfully contained. Approximately 85

percent of the data from the prime test objectives was

recovered, although about $32 million of normally

recoverable and reusable equipment was lost.34

Controlled purging of the tunnel began 12 days 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 this period.

IS THERE A REAL ESTATE

PROBLEM AT NTS?

There have been over 600 underground and 100

aboveground nuclear test explosions at the Nevada

Test Site. With testing continuing at a rate of about

a dozen tests a year, the question of whether there

will eventually be no more room to test has been

raised. While such a concern may be justified for the

most convenient areas under the simplest arrangements, it is not justified for the test area in general.

Using the drill-hole spacing of approximately onehalf the depth of burial, high-yield tests can be

spaced about 1,000 feet apart, and low-yield tests

can be spaced at distances of a few hundred feet.

Consequently, a suitable square mile of test site may

provide space for up to 25 high-yield tests or over

300 low-yield tests. Even with testing occurring at a

rate of 12 tests a year, the 1,350 square miles of test

site provide considerable space suitable for testing.

In recent years, attempts have been made to use

space more economically, so that the most convenient locations will remain available. Tests have

traditionally been spaced in only 2-dimensions. It

may be possible to space tests 3-dimensionally, that

is, with testing located below or above earlier tests.

Additionally, the test spacing has been mostly for

convenience. If available testing areas become

scarce, it may become possible to test at closer

spacing, or even to test at the same location as a

previous test.

Area for horizontal tunnel tests will also be

available for the future. The N-tunnel area has been

extended and has a sizable area for future testing.

P-tunnel, which is used for low-yield effects tests,

has only been started. (See figure 2-4 inch. 2 of this

report.) Within Rainier and Aqueduct Mesa alone,

there is enough area to continue tunnel tests at a rate

of two a year for at least the next 30 years.

Consequently, lack of adequate real estate will not

be a problem for nuclear testing for at least several

more decades.

TIRED MOUNTAIN SYNDROME?

The “Tired Mountain Syndrome” hypothesis

postulates that repeated testing in Rainier Mesa has

created a “tired” mountain that no longer has the

strength to contain future tests. Support for this

concern has come from the observation of cracks in

the ground on top of the Mesa and from seismological measurements, indicating that large volumes of

rock lose strength during an underground test.

Debate exists, however, over both the inference that

the weakened rock is a danger to containment, and

the premise that large volumes of rock are being

weakened by nuclear testing.

Basic to the concern over tired mountain syndrome is the assumption that weakened rock will

adversely affect containment. As discussed previously, only in an extreme situation, such as detonating an explosion in water-saturated clay, would rock

strength be a factor in contributing to a leak of

radioactive material. 35 For example, many tests have

34CoWa1menta~S@V Revlewfor [he ~igh~ oak N~le~r we~on Eflects Test, us, Dep~men( of Energy, Nevada Opcra[iorls Office, NVO-3 ] 1,

May 1, 1987.

~sSee earlier section “Why do nuclear tests remain contained?”
52 ● The Containment of Underground Nuclear Explosions

Photo credit: Department of Energy

Fracture on Rainier Mesa.

been detonated in alluvial deposits, which are

essentially big piles of sediment with nearly no

internal strength in an unconfined state. Despite the

weakness and lack of cohesiveness of the material,

such explosions remain well contained.

Compared to vertical drill hole tests, tunnel tests

are overburied and conservatively spaced. The

tunnel system in Rainier Mesa is at a depth of 1,300

feet. By the standards for vertical drill hole tests

(using the scaled depth formula36), this is deep

enough to test at yields of up to 34 kilotons; and yet

all tunnel tests are less than 20 kilotons.37 Consequently, all tunnel tests in Rainier Mesa are buried

at depths comparatively greater than vertical drill

hole tests on Yucca Flat. Furthermore, the minimum

separation distance of tunnel shots (twice the combined cavity radii plus 100 feet) results in a greater

separation distance than the minimum separation

distance of vertical drill hole shots (1/2 depth of

burial) for tests of the same yield (compare figures

3-2 and 3-3). Consequently, neither material

strength, burial depth, nor separation distance

would make leakage to the surface more likely for

a tunnel test on Rainier Mesa than for a vertical

drill hole tests on Yucca Flat.

Despite the relative lack of importance of strength

in preventing possible leakage to the surface, the

volume of material weakened or fractured by an

explosion is of interest because it could affect the

performance of the tunnel closures and possible

leakage of cavity gas to the tunnel complex. Dispute

over the amount of rock fractured by an underground

nuclear explosion stems from the following two,

seemingly contradictory, but in fact consistent

observations:

1. Post-shot measurements of rock samples taken

from the tunnel complex generally show no change

in the properties of the rock at a distance greater than

3 cavity radii from the point of the explosion. This

observation implies that rock strength is measurably

decreased only within the small volume of radius =

165 (yield) 1/3

,

38 where the radius is measured in feet

from the point of the explosion and the yield is

measured in kilotons (figure 3-10).

2. Seismic recordings of underground explosions

at Rainier Mesa include signals that indicate the loss

of strength in a volume of rock whose radius is

slightly larger than the scaled depth of burial. This

observation implies that the rock strength is decreased throughout the large volume of radius = 500

(yield)1/3, where the radius is measured in feet from

the point of the explosion and the yield is measured

in kilotons (figure 3-11). The loss of strength in a

large volume seems to be further supported by

cracks in the ground at the top of Rainier Mesa that

were created by nuclear tests.

The first observation is based on tests of samples

obtained from drilling back into the rock surrounding the tunnel complex after a test explosion, The

core samples contain microfractures out to a distance

from the shot point equal to two cavity radii.

Although microfractures are not seen past two cavity

radii, measurements of seismic shear velocities

sbDep~(fi) = 400” (yield(kt))lfl

37’ ‘Announced United States Nuclear 7ksts, July 1945 through December 1987,’ United States Lkpartment of Energy, NVO-209 (Rcv.8), April, 1988.

381f tie ~~w of a ~avlty prod~~d by ~ exp]oslon is equ~ to 55 (y]e]d)l~, a dlst~cc of ~~ cavity r~li would & equal [O lhrw tirncs (his, or 165

(yield)]fl.
Chapter 3--Containing Underground Nuclear Explosions ● 53

Surface

Seismic measurements and measurements taken from drill-back samples indicate a seemingly contradictory (but in fact consistent) radius

of decrease in rock strength.

SOURCE: Office of Technology Assessment, 1989.

continue to be low out to a distance of three cavity radii, seismic velocity measurements and strength

radii, The decrease in seismic shear velocity indi- tests typically show no change from their pre-shot

cates that the rock has been stressed and the strength values, although small disturbances along bedding

decreased. At distances greater than three cavity planes are occasionally seen when the tunnels are
54 ● The Containment of Underground Nuclear Explosions

recentered after the test. Such measurements suggest

that the explosion only affects rock strength to a

distance from the shot point to about three cavity

radii (165 (yield) 11

3

).

The second observation, obtained from seismic

measurements of tectonic release, suggests a larger

radius for the volume of rock affected by an

explosion. The seismic signals from underground

nuclear explosions frequently contain signals created by what is called “tectonic release. ” By

fracturing the rock, the explosion releases any

preexisting natural stress that was locked within the

rock. The release of the stress is similar to a small

earthquake. The tectonic release observed in the

seismic recordings of underground explosions from

Rainier Mesa indicate the loss of strength in a

volume of rock with a minimum radius equal to 500

(yield)1/3.

Although the drill samples and the seismic data

appear to contradict each other, the following

explanation appears to account for both: The force of

the explosion creates a cavity and fractures rock out

to the distance of 2 cavity radii from the shot point.

Out to 3 cavity radii, existing cracks are extended

and connected, resulting in a decrease in seismic

shear velocity. Outside 3 cavity radii, no new cracks

form. At this distance, existing cracks are opened

and strength is reduced, but only temporarily. The

open cracks close immediately after the shock wave

passes due to the pressure exerted by the overlying

rock. Because the cracks close and no new cracks are

formed, the rock properties are not changed. Postshot tests of seismic shear velocity and strength are

the same as pre-shot measurements. This is consistent with both the observations of surface fractures

and the slight disturbances seen along bedding

planes at distances greater than 3 cavity radii. The

surface fractures are due to surface span, which

would indicate that the rock was overloaded by the

shock wave. The disturbances of the bedding planes

would indicate that fractures are being opened out to

greater distances than 3 cavity radii. In fact, the

bedding plane disturbances are seen out to a distance

of 600 (yield)1/3, which is consistent with the radius

determined from tectonic release.

The large radius of weak rock derived from

tectonic release measurements represents the transient weakening from the shot. The small radius of

weak rock derived from the post-shot tests represents the volume where the rock properties have

been permanently changed. From the point of view

of the integrity of the tunnel system, it is the smaller

area where the rock properties have been permanently changed (radius = 165 (yield)1/3) that should

be considered for containment. Because the line-ofsight tunnel is located so that the stemming plug

region and closures are outside the region of

permanently weakened or fractured material, the

closure system is not degraded.

HOW SAFE IS SAFE ENOUGH?

Every nuclear test is designed to be contained and

is reviewed for containment. In each step of the test

procedure there is built-in redundancy and conservatism. Every attempt is made to keep the chance of

containment failure as remote as possible. This

conservatism and redundancy is essential, however;

because no matter how perfect the process may be,

it operates in an imperfect setting. For each test, the

containment analysis is based on samples, estimates,

and models that can only simplify and (at best)

approximate the real complexities of the Earth. As a

result, predictions about containment depend largely

on judgments developed from past experience. Most

of what is known to cause problems-carbonate

material, water, faults, scarps, clays, etc.—was

learned through experience. To withstand the consequences of a possible surprise, redundancy and

conservatism is a requirement not an extravagance.

Consequently, all efforts undertaken to ensure a safe

testing program are necessary, and they must continue to be vigorously pursued.

Deciding whether the testing program is safe

requires a judgement of how safe is safe enough. The

subjective nature of this judgement is illustrated

through the decision-making process of the CEP,

which reviews and assesses the containment of each

test.39 They evaluate whether a test will be contained

using the categorizations of ‘‘high confidence, ’

‘‘adequate degree of confidence, and some doubt.

But, the CEP has no guidelines that attempt to

quantify or describe in probabilistic terms what

constitutes for example, an ‘‘adequate degree of

confidence. Obviously one can never have 100

percent confidence that a test will not release

radioactive material. Whether “adequate confiWmConttiment Ev~uatlon pine} is a ~oup of rcpre=ntatlves from vfious Iakratories and technicat consulting organizations who evaluate the

proposed containment plan for each test without regard to cost or other outside considerations (see ch. 2 for a complete discussion).
Chapter 3--Containing Underground Nuclear Explosions . 55

dence” translates into a chance of 1 in 100, 1 in

1,000, or 1 in 1,000,000, requires a decision about

what is an acceptable risk level. In turn, decisions of

acceptable risk level can only be made by weighing

the costs of an unintentional release against the

benefits of testing. Consequently, those who feel

that testing is important for our national security will

accept greater risk, and those who oppose nuclear

testing will find even small risks unacceptable.

Establishing an acceptable level of risk is difficult

not only because of value judgments associated with

nuclear testing, but also because the risk is not seen

as voluntary to those outside the testing program.

Much higher risks associated with voluntary, everyday activities may be acceptable even though the

much lower risks associated with the nuclear test site

may still be considered unacceptable.

The question of whether the testing program is

‘‘safe enough’ will ultimately remain a value

judgment that weighs the importance of testing

against the risk to health and environment. In this

sense, concern about safety will continue, largely

fueled by concern about the nuclear testing program

itself. However, given the continuance of testing and

the acceptance of the associated environmental

damage, the question of ‘adequate safety’ becomes

replaced with the less subjective question of whether

any improvements can be made to reduce the

chances of an accidental release, In this regard, no

areas for improvement have been identified. This is

not to say that future improvements will not be made

as experience increases, but only that essentially all

suggestions that increase the safety margin have

been implemented. The safeguards built into each

test make the chances of an accidental release of

radioactive material as remote as possible.
Chapter 4

Monitoring Accidental

Radiation Releases
CONTENTS

Page

INTRODUCTION .. .. .. .. .. .. .. .. . ... ... ..... .. .. .. .. .. .. .. 59

WHAT IS RADIATION? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. . 59

PRODUCTS OF A NUCLEAR EXPLOSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

CRITERIA FOR CONDUCTING A TEST .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

PREDICTING FALLOUT PATTERNS .. .. .. .. .. .. .. .. ... ... ...... . . . . . . . . . . . . . 63

ACCIDENT NOTIFICATION .. ........................... . . . . . . . . . . . . . . . . . . . . . 64

Onsite Monitoring by The Department of Energy .. .. .. .. .. .. .. ... .. . . . . . . . . . . . . . . 65

Offsite Monitoring by The Environmental Protection Agency . . . . . . . . . . . . . . . . . . . . . . 66

GROUNDWATER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . 70

MONITORING CAPABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figures

Figure Page

4-1. The Typical Bimodal Curve for Fission-Product Yield . . . . . . . . . . . . . . . . . . . . . . . . . 60

4-2. Controllable and Uncontrollable Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

4-3. Projected Fallout Dispersion pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

4-4

4-5

4-6

4-7

4-8

4-9

Yield v. Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 64

Typical RAMs Array for Vertical Drill-Hole Shot . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Typical RAMs Array for Tunnel Shot . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... ... ......67

Air Monitoring Stations .. . .. . . .. ....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 69

Sample Press Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 72

Standby Air Surveillance Network Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

4-10. Locations Monitored With Thermoluminescent Dosimeters . . . . . . . . . . . . . . . . . . . . . 74

4-11. Milk Sampling Locations . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

4-12. Standby Milk Surveillance Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

4-13. Collection Site for Animals Sampled in 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

4-14. Locations of Families in the Offsite Human Surveillance Program.. ... .. . . . . . . . 78

4-15. Well Sampling Locations Onsite .. ............... . . . . . . . . . . . . . . . . . . . . . . . . . . 79

4-16. Well Sampling Locations Offside . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . 80

Tables

Table Page

4-1. Common Radionuclides Involved in a Nuclear Explosion . . . . . . . . . . . . . . . . . . . . . . . . 60

4-2. Summary of Onsite Environmental Monitoring Program . . . . . . . . . . . . . . . . . . . . . . . . . 68

4-3. Citizens Alert Water Sampling Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Chapter 4

Monitoring Accidental Radiation Releases

Each test is conducted under conditions in which remedial actions could be effective should an

accidental release of radioactive material occur.

INTRODUCTION

Although nuclear tests are designed to minimize

the chance that radioactive material could be released to the atmosphere, it is assumed as a

precaution for each test that an accident may occur.

To reduce the impact of a possible accident, tests are

conducted only under circumstances whereby remedial actions could be taken if necessary. If it is

estimated that the projected radioactive fallout from

a release would reach an area where remedial actions

are not feasible, the test will be postponed.

Responsibility for radiation safety measures for

the nuclear testing program is divided between the

Department of Energy (DOE) and the Environmental Protection Agency (EPA). The Department

of Energy oversees monitoring within the boundaries of the Nevada Test Site (NTS). The Environmental Protection Agency monitors the population

around the test site and evaluates the contribution of

nuclear testing to human radiation exposure through

air, water, and food.

WHAT IS RADIATION?

The nuclei of certain elements disintegrate spontaneously. They may emit particles, or electromagnetic waves (gamma rays or x-rays), or both. These

emissions constitute radiation. The isotopes are

called radionuclides. They are said to be radioactive,

and their property of emitting radiation is called

radioactive decay. The rate of decay is characteristic

of each particular radionuclide and provides a

measure of its radioactivity.

The common unit of radioactivity was the curie

(Ci), defined as 3.7 x 1010 decays per second, which

is the radioactivity of one gram of radium. Recently,

a new unit, the becquerel (Bq), has been adopted,

defined as one decay per second. Exposure of

biological tissue to radiation is measured in terms of

reins (standing for roentgen equivalent man). A

roentgen (R) is a unit of exposure equivalent to the

quantity of radiation required to produce one coulomb of electrical charge in one kilogram of dry air.

A rem is the dose in tissue resulting from the

absorption of a rad of radiation multiplied by a

“quality factor” that depends on the type of

radiation. A rad is defined as 100 ergs (a small unit

of energy) per gram of exposed tissue. Recently

accepted international units of

gray (Gy), equal to 100 rads,

equal to 100 reins.

radiation are now the

and the sievert (Sv),

PRODUCTS OF A NUCLEAR

EXPLOSION

A nuclear explosion creates two sources of

radioactivity: the first source is the direct products of

the nuclear reaction, and the second is the radioactivity induced in the surrounding material by the

explosion-generated neutrons. In a fission reaction,

the splitting of a nucleus creates two or more new

nuclei that are often intensely radioactive. The

products occur predominantly in two major groups

of elements as shown in figure 4-1. The neutrons

produced by the reaction also react with external

materials such as the device canister, surrounding

rock, etc., making those materials radioactive as

well. In addition to these generated radioactivities,

unburned nuclear fission fuel (especially plutonium)

is also a radioactive containment. The helium nuclei

formed by fusion reactions are not radioactive. ’

However, neutrons produced in the fusion reaction

still will make outside material radioactive. Depending on the design of the explosive device and its

percentage of fission and fusion, a wide range of

radioactive material can be released with half lives

of less than a second to more than a billion years.2

The debris from nuclear detonations contain a large

number of radioactive isotopes, which emit predominantly gamma and beta radiation. Some of the more

common radionuclides involved in a nuclear explosion are listed in table 4-1.

IThls, incldent~]y, is why ~ommercla] fusion reac[ors (If ficy Coukj ~ created) Wou]d ~ a relatively clean SOurCe Of energy.

2~e h~f.]lfe is the time re~ulred for h~f of the aloms of a radioactive substance to undergo a nuclear ~ansformation to a more stable e]emenl.

-59-
60 ● The Containment of Underground Nuclear Explosions

Figure 4-1-The Typical Bimodal Curve for

Fission-Product Yield

Mass number

Products of a nuclear explosion occur predominantly in two major

groups of nuclides.

SOURCE: Modified from Lapp and Andrews, Prentice-Hall, Inc., 1972.

An individual radioactive species follows the

half-life rule of decay—that is, half of the nuclei

disintegrate in a characteristic time. called a “halflife. ” However, a mixture of fission products has a

more complicated decay pattern. The general rule of

thumb for a nuclear explosion is that the total

activity decreases by a factor of 10 for every

sevenfold increase in time. In other words, if the

gamma radiation 1 hour after an explosion has an

intensity of 100 units, then 7 hours later it will have

an intensity of 10. Consequently. the time after the

explosion has a dramatic effect on the amount of

radioactivity. A 1 kiloton explosion in the atmosphere will produce 41 billion curies 1 minute after

determination, but this will decrease to 10 million

curies in just 12 hours.

Table 4-1--Common Radionuclides Involved in a

Nuclear Explosion

Radionuclide Half-Life

Uranium-238 . . . . . . . . . . . . . . . . . . . . . . . . .4,500,000,000 years

Plutonium-239 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24,300 years

Carbon-14 . . . . . . . . . . . . . . . . . . . . . . ............5,800 years

Radium-226 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1,620 years

Cesium-137 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 years

Strontium-90 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 years

Tritium . . . . . ., . . . . . . . . . . . . . . . . . . 12.3 years

Krypton-85 . . . . . . . . . . . . . . . . . . . . . . . . . ; 10.9 years

iodine-131 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 days

Xenon-133 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 days

iodine-132 . . . . . . . . . . . . . . . . . . . . . ...............2.4 hours

The type of release is also important in predicting

what radionuclides will be present. For example,

atmospheric tests release all radionuclides created.

Prompt, massive ventings have released a nonnegligible fraction of the radionuclides created. Latetime, minor seeps, like those since 1970, release only

the most volatile radionuclides. In an underground

explosion, radionuclides also separate (called fractionation”) according to their chemical or physical

characteristics. Refractory particles (particles that

do not vaporize during the nuclear explosion) settle

out fast underground, while more volatile elements

that vaporize easily condense later. This has a strong

effect on radioactive gases that seep slowly through

the soil from an underground explosion. In an

underground explosion, nearly all the reactive materials are filtered out through the soil column. and the

only elements that come up through the soil to the

atmosphere are the noble gases, primarily krypton

and xenon.

CRITERIA

Although every

accidental release

FOR CONDUCTING

A TEST

attempt is made to prevent the

of radioactive material to the

atmosphere, several safety programs are carried out

for each test. These programs are designed to

minimize the likelihood and extent of radiation

exposure offsite and to reduce risks to people should

an accidental release of radioactive material occur.

The Environmental Protection Agency monitors the

population around the test site and has established

plans to protect people should an accident occur.

EPA’s preparations are aimed toward reducing the

whole-body exposure of the off-site populace and to

minimizing thyroid dose to offsite residents, particu-
Chapter 3--Monitoring Accidental Radiation Releases ● 61

larly from the ingestion of contaminated milk.3 The

whole-body dose is the main concern. However,

deposition of radioactive material on pastures can

lead to concentration in milk obtained from cows

that graze on those pastures. The infant thyroid doses

from drinking milk from family cows is also

assessed. 4

The Department of Energy’s criteria for conducting a test are:

For tests at the Nevada Test Site, when considering the event-day weather conditions and the specific

event characteristics, calculations should be made

using the most appropriate hypothetical release

models which estimate the off-site exposures that

could result from the most probable release scenario.

Should such estimates indicate that off-site populations, in areas where remedial actions to reduce

whole-body exposures are not feasible, could receive

average whole-body dose in excess of 0.17 R/year

(170 mR/year), the event shall be postponed until

more favorable conditions prevail. In addition,

events may proceed only where remedial actions

against uptake of radionuclides in the food chain are

practicable and/or indications are that average thyroid doses to the population will not exceed 0.5

R/year (500 mR/year).5

These criteria mean that a test can only take place

if the estimate of the fallout from an accidental

release of radioactivity would not be greater than

0.17 R/year in areas that are uncontrollable, i.e.,

where ‘‘remedial actions to reduce whole-body

exposures are not feasible. ” Thus, tests are not

conducted when the wind is blowing in the general

direction of populated areas considered to be uncontrollable, except under persistent light wind conditions that would limit the significant fallout to the

immediate vicinity of the NTS. Areas considered to

be uncontrollable by EPA are shown in figure 4-2.

The EPA and DOE have also defined a controllable area (figure 4-2), within which remedial actions

are considered feasible. Criteria for the controllable

area, as defined by the DOE are:

. . . those 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.

The controllable area is the zone within approximately 125 miles of the test control point (see figure

4-2) for which EPA judges that its remedial actions

would be effective. Within this area, EPA has the

capability to track any release and perform remedial

actions to reduce exposure, including sheltering or

evacuation of all personnel (as needed); controlling

access to the area; controlling livestock feeding

practices, i.e., providing feed rather than allowing

grazing; replacing milk; and controlling food and

water.

In the case of the controllable area, a test may be

conducted if the fallout estimate implies that individuals in the area would not receive whole-body

doses in excess of 0.5 R/year and thyroid doses of 1.5

R/year. If winds measured by the weather service

indicate that the cloud of radioactive debris produced by the assumed venting would drift over

controllable areas, such as to the north, the test is

permitted when EPA’s mobile monitors are in the

downwind areas at populated places. EPA must be

ready to measure exposure and to assist in moving

people under cover or evacuating them, if necessary,

to keep their exposures below allowable levels.

As a consequence of the geometry of the controllable area, tests are generally not conducted if winds

aloft blow toward Las Vegas or towards other nearby

populated locations. In addition, the test will not be

conducted if there is less than 3 hours of daylight

remaining to track the cloud.

Prior to conducting a test, detailed fallout projections are made by the weather service for the

condition of “the unlikely event of a prompt

massive venting. ” Predictions are made of the

projected fallout pattern and the maximum radiation

exposures that might occur. An example of such a

prediction is shown in figure 4-3. The center line is

the predicted path of maximum fallout deposition

for a prompt venting, marked with estimated arrival

times (in hours) at various distances. Lines to either

side indicate the width of the fallout area. The two

dashed lines indicate the 500 mR/year area and the

3Ses “Offsite Remediat Action Capability for Underground Nuclear Weapons lkst Accidents, ” U.S. Environmental Protection Agency,

Environmental Monitoring Systems Laboratory--La.. Vegas, NV, October 1988.

d~ tie ~= of ~ ~ident, however, t~ ~tua] do= wo~d be minimized because the milk would ~ ~PkKed m much ~ Pssible.

SS= ‘‘Offsite Reme.dia] &tion Capability for Underground Nuclear Weapons ‘kS1 Accidents, ’ U.S. Environmental Protection Agency,

Environmental Monitoring Systems Laboratory-Las Vegas, NV, October 1988.
62 The Containment of Underground Nuclear Explosions

Figure 4-2--Controllable and Uncontrollable Areas

The controllable area is the region within which remedial actions are considered feasible.

SOURCE. Modified from Enwronmental Protection Agency

170 mR/year level. If 0.17 mR/year (the maximum postponed. Within the predictions shown in figure

external exposure allowed during a 12-month period 4-3, the test could be conducted if EPA monitors

for an uncontrolled population) or more is predicted were prepared to be at each of the ranches, mines.

to fall outside the controllable area, the test will be and other populated areas within the dispersion
Chapter 3--Monitoring Accidental Radiation Releases ● 63

Figure 4-3-Projected Fallout Dispersion Pattern

/

Glendale

●

Key: H+ number= time of detonation plus elapsed hours; mR= milliREM

Predicted fallout pattern for the case of an accidental venting.

SOURCE Modlfled from. “Public Safety for Nuclear Weapons Tests,” U.S.

Environmental Protection Agency, January 1984.

pattern to measure exposure and perform remedial

actions should they be necessary.

The preferred weather conditions for a test are a

clear sky for tracking, southerly winds (winds from

the south), no thunderstorms or precipitation that

would inhibit evacuation, and stable weather patterns. During the test preparations, the Weather

Service Nuclear Support Office provides the Test

Controller with predicted weather conditions. This

information is used by the Weather Service to derive

the estimated fallout pattern should an accidental

release occur. About one-third of all nuclear tests are

delayed for weather considerations; the maximum

delay in recent years reached 16 days.

PREDICTING FALLOUT

PATTERNS

The predicted fallout pattern from an underground

test depends on many variables related to the type of

nuclear device, the device’s material composition.

type of venting, weather conditions, etc. With so

many variables and so little experience with actual

ventings, fallout predictions can only be considered

approximations. The accuracy of this approximation, however, is critical to the decision of whether

a test can be safely conducted. Fallout predictions

are made by the Weather Service Nuclear Support

Office using up-to-date detailed weather forecasts

combined with a model for a “prompt massive

venting. ” The model uses scaling technique based

on the actual venting of an underground test that

occurred on March 13, 1964. The test, named

“Pike,’ was a low-yield (less than 20 kilotons)

explosion detonated in a vertical shaft. A massive

venting occurred 10 to 15 seconds after detonation.6

The venting continued for 69 seconds, at which time

the overburden rock collapsed forming a surface

subsidence crater and blocking further venting. The

vented radioactive debris, consisting of gaseous and

particulate material, rose rapidly to about 3,000 feet

above the surface.

The Pike scaling model has been used to calculate

estimates of fallout patterns for the past 20 years

because: 1) the large amount of data collected from

the Pike venting allowed the development of a

scaling model, and 2) Pike is considered to be the

worst venting in terms of potential exposure to the

public.7

The Pike model, however, is based on a very small

release of radioactive material compared to what

would be expected from an aboveground test of the

same size.8 The percentage of radioactive material

released from the Baneberry venting (7 percent from

table 3-l), for example, is many times greater than

the percentage of material released from the Pike

test. 9 It would therefore appear that Baneberry

provides a more conservative model than Pike. This.

however, is not the case because Baneberry was not

6PlkC ~U ~OndUC[~d in ~llUvl~ ,n ,L@~ s of’ the test site. The release Was ai~lbllied to a fr~~urc that propagated [0 tic surface. Other factor’i

contributing to the release were an inadequate depth of burial and an inadequate closure of the line-of-sight pipe.

7“ 1985 Analyses and Evaluations of the Radiological and Meteorological Data from the Pike Event, ’ National Oceanic and At.mosphcrlc

Administration, Weather Service Nuclear Support Office, Las Vegas, NV, December, 1986, NVO-308.

gThe exact ~ount Of rnatcrial released from [he 1964 Pike test remains clmsified.

gsec table 3-1 for a comparison of various rCICaSCS.
64 ● The Containment of Underground Nuclear Explosions

a prompt venting. Baneberry vented through a

fissure and decaying radioactive material was

pumped out over many hours. Baneberry released

more curies than Pike; however, due to its slower

release, a higher percentage of the Baneberry

material was in the form of noble gases, which are

not deposited. The data suggest that much less than

7 percent of the released material was deposited.10

Therefore, it is thought that Pike is actually a more

conservative model than Baneberry.

The sensitivity of the Pike model can be judged by

looking at the degree to which its predictions are

affected by the amount of material released. For

example, consider a test in which 10 percent of the

radioactive material produced by the explosion is

accidentally released into the atmosphere; in other

words, 10 percent of the material that would have

been released if the explosion had been detonated

aboveground. This also roughly corresponds to the

amount of material that would be released if the

explosion had been detonated underground at the

bottom of an open (unstemmed) hole. The 10 percent

release can therefore be used as a rough approximation for the worst case release from an underground

test. To evaluate the adequacy of the Pike model

predictions to withstand the full range of uncertainty

of an accidental release, the question is: what effect

would a release of 10 percent rather than, say 1

percent, have on the location of 170-mR and

500-mR exposure lines? As figure 4-4 illustrates,

changing the yield of an explosion by an order of

magnitude (in other words, increasing the release

from say 1 percent to 10 percent) increases the

distance of the 170-mR and 500-mR lines by

roughly a factor of 2. Therefore, assuming a worst

case scenario of a 10 percent prompt massive

venting (as opposed to the more probable scenario of

around a 1 percent prompt massive venting), the

distance of the exposure levels along the predicted

fallout lines would only increase by a multiple of 2.

The Pike model therefore provides a prediction that

is at least within a factor of about 2 of almost any

possible worst-case scenario.

ACCIDENT NOTIFICATION

Any release of radioactive material is publicly

announced if the release occurs during, or immediately following, a test. If a late-time seep occurs, the

release will be announced if it is predicted that the

1,000

100

10

0

Figure 4-4--Yield v. Distance

0 50 100 150

Distance (miles)

Constant Pike Parameters Variable

Wind speed = 15mph Yield x Pike

Vertical wind shear = 20°

Cloud rise = 5,000 ft

Yield (in kilotons) v. distance (in miles) for projected fallout using

the Pike Model. TYE indicates total first year exposure. increasing

the yield by a factor of 10 roughly doubles the downwind distance

of the projected fallout pattern.

SOURCE: Provided by National Oceanic and Atmospheric Admlnlstratlon,

National Weather sarwee Nuclear Support Ofhee, 1888.

radioactive material will be detected outside the

boundaries of the test site. If no detection off-site is

predicted, the release may not be announced.

Operational releases that are considered routine

(such as small releases from drill-back operations)

are similarly announced only if it is estimated that

they will be detected off-site.

The Environmental Protection Agency is present

at every test and is therefore immediately aware of

any prompt release. The Environmental Protection

Agency, however, is not present at post-test drillback operations. In the case of late-time releases or

operational releases, the Environmental Protection

Agency depends on notification from the Department of Energy and on detection of the release (once

1OBmc&~, however, had a limited data WI of usable radioactive readings.
Chapter 4-Monitoring Accidental Radiation Releases ● 65

it has reached outside the borders of the test site) by

the EPA offsite monitoring system.

Estimates of whether a particular release will be

detected offsite are made by the Department of

Energy or the sponsoring laboratory. Such judgments, however, are not always correct. During the

drill-back operations of the Glencoe test in 1986,

minor levels of radioactive material were detected

offsite contrary to expectations. During the Riola

test in 1980, minor amounts of radioactive inert

gases were detected offsite. In both cases, DOE

personnel did not anticipate the release to be

detected offsite and therefore did not notify EPA.l1

Although the releases were extremely minor and

well-monitored within the test site by DOE, EPA

was not aware of the release until the material had

crossed the test site boundaries. Both cases fueled

concern over DOE’s willingness to announce accidents at the test site. The failure of DOE to publicly

announce all releases, regardless of size or circumstance, contributes to public concerns over

the secrecy of the testing program and reinforces

the perceptions that all the dangers of the testing

program are not being openly disclosed.

Onsite Monitoring by the

Department of Energy

The Department of Energy has responsibility for

monitoring within the boundaries of the Nevada Test

Site to evaluate the containment of radioactivity

onsite and to assess doses-to-man from radioactive

releases as a result of DOE operations. To achieve

these objectives, DOE uses a comprehensive monitoring system that includes both real-time monitoring equipment and sample recovery equipment. The

real-time monitoring system is used for prompt

detection following a test, the sample recovery

equipment is used to assess long-term dose and risk.

The heart of the real-time monitoring system is a

network of Remote Area Monitors (RAMs). For all

tests, RAMs are arranged in an array around the test

hole (figure 4-5). Radiation detectors are also

frequently installed down the stemming column so

the flow of radioactive material up the emplacement

hole can be monitored. In tunnel shots, there are

RAMs above the shot point, throughout the tunnel

complex, outside the tunnel entrance, and in each

containment vessel (figure 4-6). In addition to

RAMs positioned for each shot, a permanent RAM

network with stations throughout the test site is in

continual operation.

During each test, a helicopter with closed-circuit

television circles the ground zero location. Nearby.

a second helicopter and an airplane are prepared to

track any release that might occur. A third helicopter

and an airplane remain on stand-by should they be

needed. In addition, a team (called the ‘‘Bluebird

Team’ ‘), consisting of trained personnel in 2 fourwheel drive vehicles outfitted with detection equipment and personnel protection gear is stationed near

the projected fallout area to track and monitor any

release. Approximately 50 radiation monitoring

personnel are available on the Nevada Test Site to

make measurements of exposure rates and collect

samples for laboratory analysis should they be

needed. Prior to the test, portions of the test site are

evacuated unless the operation requires manned

stations. If manned stations are required. direct

communication links are established with the workers and evacuation routes are set-up.

In addition to the real-time monitoring network,

air and water samples are collected throughout the

Test Site and analyzed at regular intervals. This

comprehensive environmental monitoring program

is summarized in table 4-2. The network of samplers

located throughout the Test Site includes 160

thermoluminescent dosimeters; over 40 air samplers

that collect samples for analysis of radioiodines.

gross beta, and plutonium-239: and about half a

dozen noble gas samplers. Each year over 4.500

samples are collected and analyzed for radiological

measurement and characterization of the Nevada

Test Site, All sample collection, preparation, analysis, and review are performed by the staff of the

Laboratory Operations Section of REECO’s Environmental Sciences Department.

In the case of a prompt, massive accidental release

of radioactive material, the following emergency

procedures would be initiated:

1. any remaining test site employees downwind

of the release would be evacuated,

2. monitoring teams and radiological experts

would be dispatched to offsite downwind

areas,

I I[n tie case of Rio]a, [he release ~currcd ]n the cvcnlng and was not reported until tic following morning, AS a resull, II was 12’/2 hours before EpA

was notified.
66 ● The Containment of Underground Nuclear Explosions

Figure 4-5--Typical RAMs Array for Vertical

Drill-Hole Shot

rd.

In addition to the RAMs located down the drill hole, nine RAMs are

placed at the surface around the test hole.

SOURCE: Modified from Department of Energy

3. ground and airborne monitoring teams would

measure radioactive fallout and track the

radioactive cloud,

4. Federal, State, and local authorities would be

notified, and

5. if necessary, persons off-site would be requested to remain indoors or to evacuate the

area for a short time. 12

Offsite Monitoring by the Environmental

Protection Agency

Under an interagency agreement with the Department of Energy, the Environmental Protection

Agency is responsible for evaluating human radiation exposure from ingesting air, water, and food that

may have been affected by nuclear testing. To

accomplish this, EPA collects over 8,700 samples

each year and performs over 15,000 analytical

measurements on water, milk, air, soil, humans,

plants, and animals. 13 The sampling system and

results are published annually in EPA’s “Offsite

Environmental Monitoring Report, Radiation Monitoring Around United States Nuclear Test Areas. ”

The heart of the EPA monitoring system is the

network of 18 community monitoring stations. The

community monitoring program began in 1981 and

was modeled after a similar program instituted in the

area surrounding the Three Mile Island nuclear

reactor power plant in Pennsylvania. Community

participation allows residents to verify independently the information being released by the government and thereby provide reassurance to the community at large. The program is run in partnership with

several institutions. The Department of Energy

funds the program and provides the equipment. The

Environmental Protection Agency maintains the

equipment, analyzes collected samples, and interprets results. The Desert Research Institute manages

the network, employs local station managers, and

independently provides quality assurance and data

interpretation. The University of Utah trains the

station managers selected by the various communities. Whenever possible, residents with some scientific training (such as science teachers) are chosen as

station managers.

There are 18 community monitoring stations

(shown as squares in figure 4-7) located around the

test site. The equipment available to each station

includes: 14

Noble Gas Samplers: These samplers compress

air in a tank. The air sample is then analyzed to

measure the concentration of such radioactive noble

gases as xenon and krypton.

Tritium Sampler: These samplers remove moisture from the air. The moisture is then analyzed to

measure the concentration of tritium in the air.

Particulate and Reactive Gases Sampler: These

samplers draw 2 cubic feet of air per minute through

a paper filter and then through a canister of activated

charcoal. The paper filter collects particles and the

charcoal collects reactive gases. Both are analyzed

for radioactivity.

lzM~ificd from “@site Environmcn[a] ReporI for the Nevada Test Site” (January 1987 through Deccmbcr 1987), Daniel A. Gonzalez, REECO.,

Inc., DOEJNV/10327-39,

lsln addition, EPA annua]ly visi(s each location outside the Nevada Test Site where a nLICkW ttXt has @XunCd.

Id’’commwity Radiation Monitoring Program, ’ U.S. Environmental Protection Agency, January 1984.
Chapter 4--Monitoring Accidental Radiation Releases ● 67

Figure 4-6--Typical RAMs Array for Tunnel Shot (“Mission Cyber,” Dec. 2, 1988)

Surface Locations

●

A total of 41 RAMs (15 above the surface, 26 belowground) are used to monitor the containment of radioactive material from a horizontal

tunnel test.

SOURCE: Modified from Department of Energy.

Thermoluminescent Dosimeter (TLD): When

heated (thermo-), the TLD releases absorbed energy

in the form of light (-luminescent). The intensity of

the light is proportional to the gamma radiation

absorbed, allowing calculation of the total gamma

radiation exposure.

Gamma Radiation Exposure Rate Recorder: A

pressurized ion chamber detector for gamma radiation is connected to a recorder so that a continuous

record of gamma radiation is obtained and changes

in the normal gamma radiation level are easily seen.

Microbarograph: This instrument measures and

records barometric pressure. The data are useful in

interpreting gamma radiation exposure rate records.

At lower atmospheric pressure, naturally occurring

radioactive gases (like radon) are released in greater

amounts from the Earth’s surface and their radioactive decay contributes to total radiation exposure.
68 ● The Containmen of Underground Nuclear Explosions

Table 4-2-Summary of Onsite Environmental Monitoring Program

Collection Number

Sample type Description frequency of locations Analysis

Air . . . . . . . . . . . . . . . . . . . . . Continuous sampling through Weekly 44 Gamma Spectroscopy gross beta, Pu-239

gas filter & charcoal cartridge

Low-volume sampling through Biweekly 16 Tritium (HTO)

silica gel

Continuous low volume Weekly 7 Noble gases

Potable water . . . . . . . . . . . . 1-liter grab sample Weekly 7 Gamma Spectroscopy gross beta, tritium Pu239 (quarterly)

Supply wells . . . . . . . . . . . . . l-liter grab sample Monthly 16 Gamma Spectroscopy gross beta, tritium Pu239 (quarterly)

Open reservoirs . . . . . . . . . . l-liter grab sample Monthly 17* Gamma Spectroscopy gross beta, tritium Pu239 (quarterly)

Natural springs . . . . . . . . . . . l-liter grab sample Monthly 9* Gamma Spectroscopy gross beta, tritium Pu239 (quarterly)

Ponds (contaminated) . . . . . l-liter grab sample Monthly 8* Gamma Spectroscopy gross beta,tritium Pu239 (quarterly)

Ponds (effluent) . . . . . . . . . . l-liter grab sample Monthly 5 Gamma Spectroscopy gross beta, tritium Pu239 (quarterly)

External gamma radiation

levels . . . . . . . . . . . . . . . . . Thermoluminescent Semi- 1s3 Total integrated exposure over field cycle

Dosimeters annually

*Not all of these locations were sampled due to inaccessibility or lack of water.
Chapter 4--Monitoring Accidental Radiation Releases . 69

Figure 4-7-Air Monitoring Stations

Nevada

Salt Lake City

e

Vegas

)

1

Delta ■

I

I

I

Arizona

SOURCE: Modified from Environmental Protection Agency.
70 ● The Containment of underground Nuclear Explosions

The monitoring stations are extremely sensitive; they can detect changes in radiation exposure

due to changing weather conditions. For example,

during periods of low atmospheric pressure, gamma

exposure rates are elevated on the order of 2 to 4

uR/hr because of the natural radioactive products

being drawn out of the ground. To inform the public,

data from the community monitoring stations are

posted at each station and sent to local newspapers

(figure 4-8).

In addition to the 18 community monitoring

stations, 13 other locations are used for the Air

Surveillance Network (shown as circles in figure

4-7) to monitor particulate and reactive gases. The

air surveillance network is designed to cover the area

within 350 kilometers of the Nevada Test Site, with

a concentration of stations in the prevailing downwind direction. The air samplers draw air through

glass fiber filters to collect airborne particles (dust).

Charcoal filters are placed behind the glass fiber

filters to collect reactive gases. These air samplers

are operated continuously and samples are collected

three times a week. The Air Surveillance Network is

supplemented by 86 standby air sampling stations

located in every State west of the Mississippi River

(figure 4-9). These stations are ready for use as

needed and are operated by local individuals or

agencies. Standby stations are used 1 to 2 weeks

each quarter to maintain operational capability and

detect long-term trends.

Noble gas and tritium samplers are present at 17

of the air monitoring stations (marked with asterisk

in figure 4-7). The samplers are located at stations

close to the test site and in areas of relatively low

altitude where wind drains from the test site. Noble

gases, like krypton and xenon, are nonreactive and

are sampled by compressing air in pressure tanks.

Tritium, which is the radioactive form of hydrogen,

is reactive but occurs in the form of water vapor in

air. It is sampled by trapping atmospheric moisture.

The noble gas and tritium samplers are in continuous

operation and samples are recovered and analyzed

weekly.

To monitor total radiation doses, a network of

approximately 130 TLDs is operated by EPA. The

network encircles the test site out to a distance of

about 400 miles with somewhat of a concentration in

the zones of predicted fallout (figure 4-10). The TLD

network is designed to measure environmental

radiation exposures at a location rather than exposures to a specific individual. By measuring exposures at fixed locations, it is possible to determine

the maximum exposure an individual would have

received had he or she been continually present at

that location. In addition, about 50 people living near

the test site and all personnel who work on the test

site wear TLD’s. All TLD’s are checked every 3

months for absorbed radiation.

Radioactive material is deposited from the air

onto pastures. Grazing cows concentrate certain

radionuclides, such as iodine-131, strontium-90. and

cesium-137 in their milk. The milk therefore becomes a convenient and sensitive indicator of the

fallout. The Environmental Protection Agency analyzes samples of raw milk each month from about 25

farms (both family farms and commercial dairies)

surrounding the test site (figure 4-11 ). In addition to

monthly samples, a standby milk surveillance network of 120 Grade A milk producers in all States

west of the Mississippi River can provide samples in

case of an accident (figure 4-12). Samples from the

standby network are collected annually.

Another potential exposure route of humans to

radionuclides is through meat of local animals.

Samples of muscle, lung, liver, kidney, blood. and

bone are collected periodically from cattle purchased from commercial herds that graze northeast

of the test site. In addition, samples of sheep, deer,

horses, and other animals killed by hunters or

accidents are used (figure 4-1 3). Soft tissues are

analyzed for gamma-emitters. Bone and liver are

analyzed for strontium and plutonium; and blood/

urine or soft tissue is analyzed for tritium.

A human surveillance program is also carried out

to measure the levels of radioactive nuclides in

families residing in communities and ranches around

the test site (figure 4-14). About 40 families living

near the test site are analyzed twice a year. A

whole-body count of each person is made to assess

the presence of gamma-emitting radionuclides.

GROUNDWATER

About 100 underground nuclear tests have been

conducted directly in the groundwater. In addition,

many pathways exist for radioactive material from

other underground tests (tests either above or below

the water table) to migrate from the test cavities to

the groundwater. To detect the migration of radioactivity from nuclear testing to potable water sources,

a long-term hydrological monitoring program is
Chapter 4--Monitoring Accidental Radiation Releases . 71

Photo credit: David Graham, 1988

Whole Body Counter, Environmental Protection Agency.

managed by the Environmental Protection Agency elides from underground tests, DOE drilled a test

at the Department of Energy’s direction with advice

on sampling locations being obtained from the U.S.

Geological Survey. Whenever possible, water samples are collected from wells downstream (in the

direction of movement of underground water) from

sites of nuclear detonations. On the Nevada Test

Site, about 22 wells are sampled monthly (figure

4-15). The 29 wells around the Nevada Test Site

(figure 4-16) are also sampled monthly and analyzed

for tritium semiannually.

well near a nuclear weapons test named ‘‘Cambric.

Cambric had a yield of 0.75 kilotons and was

detonated in a vertical drill hole in 1965. A test well

was drilled to a depth of 200 feet below the cavity

created by Cambric. It was found that most of the

radioactivity produced by the test was retained

within the fused rock formed by the explosion,

although low concentrations of radioactive material

were found in the water at the bottom of the cavity.

A satellite well was also drilled 300 feet from the

The flow of groundwater through the Nevada Test cavity. More than 3 billion gallons of water were

Site is in a south-southwesterly direction. The flow pumped from the satellite well in an effort to draw

speed is estimated to be about 10 feet per year, water from the region of the nuclear explosion. The

although in some areas it may move as fast as 600 only radioactive materials found in the water were

feet per year. To study the migration of radionu- extremely small quantities (below the permitted

15SW ‘ 6 Radjonu~]jdc Migralion In Groundwtimr ~1 NTS, ” U.S. Depanmcnt of Energy, Septcmber, 1987.
72 ● The Containment of Underground Nuclear Explosions

Figure 4-8-Sample Press Release

Alamo, NV

COMMUNITY RADIATION MONITORING REPORT

Dell Sullivan, Manager of the Community Radiation Monitoring Station in

Alamo, NV reported the results of the radiation measurements at this station

for the period July 11 to July 20, 1988. The average gamma radiation exposure

rate recorded by a Pressurized Ion Chamber at this station was 13.0

microroentgens* per hour as shown on the chart.

AVERAGE GAMMA RADIATION EXPOSURE RATE

RECORDED ON THE PRESSURIZED ION CHAMBER AT

ALAMO, NV, DURING THE WEEK ENDING JULY 20, 1988

o 10 20 30

Microroentgens Per Hour

The averages of the 16 Community Monitoring Stations operated for the

Environmental Protection Agency, Department of Energy and the Desert

Research Institute varied from 6.2 microroentgens per hour at Las Vegas, NV

to 20.2 microroentgens per hour at Austin, NV. All of the rates for the past week

were within the normal background range for the United States as shown on the

accompanying chart. Environmental radiation exposure rates vary with

altitude and natural radioactivity in the soil. Additional information and

detailed data obtained from Community Radiation Monitoring Network

Stations, including an annual summary of the results from all monitoring

around the Nevada Test Site, can be obtained from Mr. Sullivan (702) 725-3544

or by calling Charles F. Costa at the EPA in Las Vegas (702) 798-2305.

“The roent en is a measure of exposure to X or gamma radiation. A microroent en is 1

millionth o a f roentgen. For comparison, one chest x-ray results in an exposure of 1 ,000 to 5

20,000 microroentgens.

t Sum Of cosmic PIUS tefiestrial dose rates in air in the U.S.(PP3’7,42, BEIR ~~~, 1980).

Example of community radiation monitoring report that is posted at each monitoring station and sent to the press.

SOURCE. Environmental Protection Agency.
Chapter 4--Monitoring Accidental Radiation Releases . 73

Figure 4-9-Standby Air Surveillance Network Stations

,

Scale in Miles

u ‘ \

Texas

100 300 500

86 standby air surveillance stations are available and samples are collected and analyzed every 3 months to maintain a data base.

SOURCE: Modified from Environmental Protection Agency,

level for drinking water) of krypton-85, chlorine-36,

ruthenium-106, technetium-99 and iodine-1 29.

Radioactive material from nuclear testing moves

through the groundwater at various rates and is

filtered by rock and sediment particles. Tritium,

however, is an isotope of hydrogen and becomes

incorporated in water molecules. As a result, tritium

moves at the same rate as groundwater. Tritium is

therefore the most mobile of the radioactive materials. Although tritium migrates, the short half-life of

tritium (12.3 years) and slow movement of the

groundwater prevents it from reaching the Test Site

boundary. No analysis of groundwater has ever

found tritium at a distance greater than a few

hundred meters from some of the old test sites. None

of the water samples collected outside the bounda-
74 ● The Containment of Underground Nuclear Explosions

Figure 4-10-Locations Monitored With Thermoluminescent Dosimeters (TLDs)

Lake {

Tahoe

Arizona

One hundred thirty locations are monitored with TLDs. All TLDs are checked every 3 months for absorbed radiation.

SOURCE: Modified from Environmental Protection Agency.

ries of the test site has ever had detectable levels of groundwater contamination offsite of the Nevada

radioactivity attributable to the nuclear testing Test Site.

program. An independent test of water samples from

around the test site was conducted by Citizen Alert

(Reno, Nevada) at 14 locations (table 4-3).

MONITORING CAPABILITY

The combination of: 1) the monitoring system

Citizen Alert found no detectable levels of tritium deployed for each test, 2) the onsite monitoring

or fission products in any of their samples. With- system run by DOE, and 3) the offsite monitoring

standing any major change in the water table, there system run by EPA, forms a comprehensive deteccurrently appears to be no problem associated with tion system for radioactive material. There is
Chapter Monitoring Accidental Radiation Releases ● 75

Figure 4-11-Milk Sampling Locations

o 50 100 150

Scale in Kilometers

John Deer ●

●

●

Brent Jones

Dairy

● SF and K Dairy

I

Samples of raw milk are collected each month from about 25 farms surrounding the test site.

SOURCE’ Modified from Environmental ProtectIon Agency
76 ● The Containment of Underground Nuclear Explosions

Figure 4-12-Standby Milk Surveillance Network

All major milksheds west of the Mississippi River are part of the standby milk surveillance network.

Samples are collected and analyzed annually.

SOURCE: Modfmd from Environmental Protection Agency

essentially no possibility that a significant release

of radioactive material from an underground

nuclear test could go undetected. Similarly, there

is essentially no chance that radioactive material

could reach a pathway to humans and not be

discovered by the Environmental Protection Agency.

Allegations that a release of radioactive material

could escape from the test site undetected are based

on partial studies that only looked at a small portion

of the total monitoring system. 16 Such criticisms are

invalid when assessed in terms of the total monitoring system.

The radiation monitoring system continues to

improve as new measurement systems and techniques become available and as health risks from

radiation become better understood. Assuming that

the monitoring effort will continue to evolve, and

that such issues as the migration of radioactive

material in groundwater will continue to be aggressively addressed, there appear to be no valid criticisms associated with the containment of underground nuclear explosions. This is not to say that

future improvement will not be made as experience

increases, but only that essentially all relevant

suggestions made to date that increase the safety

margin have been implemented.

Public confidence in the monitoring system suffers from a general lack of confidence in the

Department of Energy that emanates from the

environmental problems at nuclear weapons production facilities and from the radiation hazards associated with past atmospheric tests. In the case of the

1%x for example, ‘‘A review of off-si[c cnvironmcrmd monitoring of tic Nevada Test Site,’ Bcmd Franke, Health Effcm of Underground Nuclear

Tests, Oversight Hearing before the Subcomml[me on Energy and the Environment of the Committee on Interior and Insular Affairs, House of

Repre.senta[ives, Sep!. 25, 1987, Scr]al No. 1[)0-?5, pp. 120-144.
Chapter 4--Monitoring Accidental Radiation Releases ● 77

Figure 4-13-Collection Site for Animals Sampled In 1987

Bighorn Sheep

❑ Mule Deer

Nevada Test Site

Depending on availability, an assortment of animals are analyzed each year.

SOURCE Modified from Environmental Protection Agency.
78 ● The Containment of Underground Nuclear Explosions

Table 4-3-Citizen Alert Water Sampling Program

Location Type of Sample

Springdale Ranch Well (hose)

Barley Hot Springs Stream

3 mi. south of Flourspar Canyon Amargosa River

Lathrop Wells Spigot at gas station

Point of Rock Spring, Ash Meadows Pond

Devils Hole, Ash Meadows Pool

Shoshone, CA Stream

Amargosa Junction Well (hose)

Goldfield Well (spigot at gas station)

Moore’s Station Pond

Six Mile Creek Stream

Tybo and Route 6 (DOE facility) Well (tap)

Hot Creek and Route 6 Stream

Blue Jay Well (hose)

SOURCE: Citizen Alert, 1988

underground nuclear testing program, this mistrust

is exacerbated by the reluctance on the part of the

Department of Energy to disclose information concerning the nuclear testing program, and by the

knowledge that not ail tests that release radioactive

material to the atmosphere (whatever the amount or

circumstances) are announced. This has led to

allegations by critics of the testing program that:

. . . the Energy Department is continuing its misinformation campaign by refusing to disclose the size

of most underground tests, by hushing up or

downplaying problems that occur and by not announcing most tests in advance, thereby leaving

people downwind unprepared in the event of an

accidental release of radioactive materials. 17

Such concern could be greatly mitigated if a

policy were adopted such that all tests were announced, or at least that all tests that released any

radioactive material to the atmosphere (whatever the

amount or circumstances) were announced.

Figure 4-14-Locations of Families in the Offsite Human Surveillance Program

Nevada
Chapter 4-Monitoring Accidental Radiation Releases . 79

Figure 4-15-Well Sampling

\

Well UE 18

● well 3

● well 4

ic
80 ● The Containment of Underground Nuclear Explosions

Figure 4-16-WelI Sampling Locations Offsite

● Adaven Springs

● Crystal Springs

● Alamo

O 10 20‘ 30 I 40 50 60

Scale in Kilometers

31 wells around the Nevada Test Site are sampled twice a year.

SOURCE: Modified from Department of Energy.

●

Las Vegas

well #28

Lake Mead ●

Intake

Related OTA Report

. Seismic Verification of Nuclear Testing Treaties.

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NTIS order #PB 88-214 853/XAB.

NOTE: RepOm m available ilorn the U.S. Govemmcnt priming office, Supaintendent of Decurnent% Wash@on, D.C. 20402-9325 (202-783-3238):

and the National lkchnical Information Service, 5285 Port Royal Road, Springfield, VA 22161-0001 (703-487-4650).