Historical Records Declassification Guide CG-HR-1

Appendix
Restricted Data, Formerly Restricted Data

Since their introduction at the end of World War II, nuclear weapons have been seen as so radically different from other weaponry, so uniquely destructive, that extraordinary measures are needed to slow their spread. To this end, Congress enacted the Atomic Energy Act to assure firm government control over all aspects of nuclear technology relating to the creation, design, production, or use of nuclear weapons. An important element of this control is the Restricted Data (RD) system, established by the Act to secure nuclear weapons-related information by providing it with a unique system of classification. RD is defined by section 11y of the Act:

The term "Restricted Data" means all data concerning (1) design, manufacture, or utilization of atomic weapons; (2) the production of special nuclear material; or (3) the use of special nuclear material in the production of nuclear energy; but shall not include data declassified or removed from the Restricted Data category pursuant to section 142.

This statute-based system operates outside of the National Security Information (NSI) system established by Executive order for all other Government classified information.

RD is specifically exempted from all provisions of E.O. 12958. In particular, RD is never subject to automatic declassification but can only be declassified by the Secretary of Energy or delegated DOE authority. RD is generally technical. Some of it has enduring value so long as it is not compromised. In the hands of an adversary, a nuclear weapon based on a 40-year-old design could be as great a threat as a modern weapon.

This Appendix is intended to aid the document reviewer in detecting the possible presence of classified nuclear information in NSI classified documents, which may be improperly marked, to reflect the presence of either RD or Formerly Restricted Data (FRD), which despite the name is classified but deals with military utilization of nuclear weapons. Much information that was once RD or FRD has been declassified over the years. Therefore, information fitting the descriptions or containing key words provided below is not necessarily classified as RD or FRD but should be referred to DOE for review and final determination.

Information classified as RD or FRD is likely to be found in documents dealing with any of the following areas:

Nuclear weapon design, fabrication, and utilization
Nuclear weapons apply the physical phenomenon of nuclear fission -- the splitting of a heavy atomic nucleus (uranium and/or plutonium) by absorption of a neutron -- to cause the release of explosive energy ("yield") many orders of magnitude greater than would be possible from a similar amount of ordinary high explosives. Some nuclear weapons also use the process of thermonuclear fusion -- the joining together of light nuclei at very high temperatures -- to produce additional yield by "boosting" the fission explosion with extra neutrons, or in a separate thermonuclear "stage" (e.g., the "hydrogen bomb"). Information revealing weapon configurations, design principles and details, mode of operation, tests, yields, methods for command/control, disablement, vulnerabilities to sabotage or countermeasures, and storage or deployment locations may be and usually is classified. RD or FRD (but not bearing RD or FRD markings) is perhaps most likely to be found in NSI documents dealing with weapon delivery systems such as missiles or aircraft, or with defense against such systems.

Inertial confinement fusion
This laboratory-scale research attempts to use certain directed power sources -- typically very large lasers, but also accelerator-produced particle beams -- to compress and heat a tiny target containing small quantities of fusion fuel (deuterium and tritium) to thermonuclear ignition conditions. The resulting "microexplosion" would resemble a miniaturized thermonuclear weapon. Therefore, target design and operation information judged to be particularly revelatory of related nuclear weapons technology is classified.

Military nuclear reactors
Nuclear reactors use the fission reaction to generate energy for conversion to electric power or other application, but in a much slower, controlled manner than occurs in a nuclear explosion. Information in this area will include design, development, test, and operation of reactor power systems for military purposes, especially for naval nuclear propulsion, and information concerning capabilities and vulnerabilities. The emphasis here is on "military" or "naval," since all aspects of civilian nuclear power (e.g., commercial electric power generation) are unclassified.

Nuclear material production
The most certain way to discourage the proliferation of nuclear weapons is to deny access to fissile materials such as plutonium or enriched uranium. Plutonium does not occur naturally in any significant quantity, but must be produced in nuclear reactors designed especially for this purpose. The unstable hydrogen isotope tritium, required for boosting fission weapons, is also made in such reactors. Information describing detailed features of the production process may be RD. Fuel reprocessing, in which the spent reactor fuel is put through a sequence of chemical operations to extract the product plutonium, is an important part of the production process.

Isotope separation
Unlike plutonium, uranium occurs naturally and is relatively plentiful. However, only the lighter isotope U-235 (0.7% of the natural element) is useful for a fission explosion using thermal neutrons. Extracting this isotope from natural uranium requires a process that can separate the U-235 from the slightly heavier but much more common isotope U-238. This has been done by diffusion techniques, which exploit slight thermal speed differences between gas molecules containing the different isotopes; by electromagnetic and centrifuge techniques, which exploit the difference in inertial mass; and by laser separation techniques, which exploit isotopic differences in atomic spectra. Potentially classified information includes process and design details of these different isotope separation methods, and the amounts and specifications of material prepared for the weapons program.

Key words and phrases that could indicate the presence of RD/FRD

Atomic or nuclear device, weapon, explosive, or warhead
anti-tampering device
boosted, boosting
channel, radiation channel
D-T gas
deployments
detonator, detonation system
deuterium, (D, 2 H)
dial-a-yield, selectable yields
dimensions, weights
disablement, command disablement
enhanced radiation
Fat Man (Trinity test, Nagasaki combat drop)
firing set
fission
fusion, thermonuclear fusion
gun-assembled
height-of-burst
highly enriched uranium (HEU)
hydrogen weapon, hydrogen bomb
hydronuclear experiment, test
implosion
initiator, initiation, pre-initiation
insensitive high explosive (IHE)
interstage coupling
interval time
Joint Task Force (JTF)
limited-life component
lithium, lithium deuteride
Little Boy (Hiroshima combat drop)
neutron generator
nuclear test, test series
one-point safe
oralloy
permissive action link, PAL
pit, sealed pit
Plowshare Program
plutonium (Pu), weapon-grade plutonium
primary
Project Matterhorn
Project Whitney
pusher
radiation flow
radiation implosion
radiation case
release codes
reservoir, gas reservoir
safing
salvage fuze
scaled depth of burial (SDOB)
secondary
staged, second stage
stockpile
tamper
Trinity
tritium (T, 3 H)
tuballoy
uranium
weapons-grade [material]
X-unit
yield (kilotons, megatons)
yield-to-weight
Weapon configurations
Schematic depictions of nuclear weapons may be found in NSI documents that are lacking RD markings. Figures likely to be encountered will resemble either a single circle (have one center) for single stage weapons, or two adjacent circles (i.e., two centers of symmetry) for a staged or thermonuclear weapon. This is only a rough characterization. Weapons schematics would be considered RD.
Nuclear weapon outputs and effects
blackout, radar blackout
damage radius
effects test
electromagnetic pulse (EMP)
enhanced radiation
fallout
fireball
gamma radiation
hardening
line-of-sight pipe
neutron, neutron radiation, neutron spectrum
radiation, especially prompt radiation or radiation dose
radiochemical tracer
tailored outputs
vulnerability
x-ray spectrum
Inertial confinement fusion (ICF)
direct drive
hohlraum
ICF target
indirect drive
laser fusion
particle-beam (light ion, heavy ion) fusion
Military nuclear reactors
quieting
directed nuclear energy
naval reactors
naval nuclear propulsion
space nuclear power
Reactor Production of special nuclear materials (SNM)
fuel reprocessing
Hanford reactors
N-reactor
plutonium production
production reactor
PUREX process
Savannah River reactors
tritium production
Isotope separation
atomic vapor laser isotope separation (AVLIS)
cascade
deuterium production
diffuser
diffusion barrier
electromagnetic separation -- Calutron
enrichment
gas centrifuge
gaseous diffusion
laser isotope separation
lithium enrichment
molecular laser isotope separation (MLIS)
thermal diffusion
uranium hexafluoride
uranium enrichment

Sites/Organizations

U.S. nuclear weapons have been designed at the Los Alamos, Livermore, and Sandia Laboratories, and manufactured in a production complex that has changed with time but always been spread over the United States. Key sites and organizations that may be found in conjunction with nuclear information and potential RD:

Albuquerque Operations Office (ALO)
ACF Industries
Air Force Office - Atomic Testing (AFOAT)
Air Force Special Weapons Center (AFSWC)
Air Force Technical Applications Center (AFTAC)
Amchitka
Armed Forces Special Weapons Project (AFSWP)
Assistant to the Secretary of Defense, Atomic Energy (ATSD-AE)
Atomic Energy Act (AEA)
Atomic Energy Commission (AEC)
Atomic Weapons Establishment (AWE), UK
Atomic Weapons Research Establishment (AWRE), UK
Bendix Kansas City
Bethe Panel
Bettis Atomic Power Laboratory
Bikini, Bikini atoll
Burlington Industries
Christmas Island
Defense Atomic Support Agency (DASA)
Defense Threat Reduction Agency (DTRA)
Division of Military Application (DMA)
Energy Research and Development Administration (ERDA)
Eniwetok, Enewetak
Fernald
GE Pinellas
Hanford
Hiroshima
Johnston Island
Joint Committee on Atomic Energy (JCAE)
Knolls Atomic Power Laboratory
Lawrence Radiation Laboratory (LRL)
Lawrence Livermore National Laboratory (LLNL)
Los Alamos National Laboratory (LANL)
Los Alamos Scientific Laboratory (LASL)
Manhattan Project, Manhattan Engineering District
Military Liaison Committee
Mound Laboratories
Nagasaki
Nevada Operations Office (NVO)
Nevada Test Site (NTS)
Nuclear weapons complex
Oak Ridge Y-12
Oak Ridge K-25
Pacific Test Range
Pantex
Paducah Site or Gaseous Diffusion Plant
Pittsburgh Naval Reactors Office
Portsmouth Site or Gaseous Diffusion Plant
Richland
Rocky Flats
Sandia National Laboratory (SNL)
Sandia Laboratories (SL)
Savannah River
University of California Radiation Laboratory (UCRL)

Possible markings

The markings listed below would indicate that the document may contain RD or FRD, even if not otherwise marked:

Atomal (NATO)
ATOMIC (UK)
Cosmic (NATO)
Critical Nuclear Weapon Design Information (CNWDI)
NNPI (Naval Nuclear Propulsion Information)
Protect as Restricted Data (PARD)
Sigma [n], where n is a number
Weapon Data

If Potential RD/FRD is Encountered

If the reviewer, using the information provided above, suspects that a NSI classified document may contain RD/FRD, the document should be marked

"MAY CONTAIN RESTRICTED DATA
NOT SUBJECT TO AUTOMATIC
DECLASSIFICATION
Requires review by the Department of Energy
prior to public release"

and directions for further action requested from the following contact in the Office of Declassification, DOE: Document Declassification Division, (301) 903-4199.


Acronym List

ADC
Authorized Derivative Classifier
AEA
Atomic Energy Act
AEC
Atomic Energy Commission
AIS
Automated Information System
AOSS
Automated Office Support Systems
CG-HR-1
Historical Records Declassification Guide
CG-RN-1
DOE-DOD Classification Guide for the Naval Nuclear Propulsion Program
COMSEC
Communications Security
DDE
Declassification Date or Event
DOD
Department of Defense
DOE
Department of Energy
DOS
Department of State
EMP
Electromagnetic Pulse
EMR
Electromagnetic Radiation
E.O.
Executive Order
ERDA
Energy Research & Development Association
FRD
Formerly Restricted Data
ID
Inventory Differences
IND
Improvised Nuclear Device
ISOO
Information Security Oversight Office
MFD
Military First Destination
NEST
Nuclear Emergency Search Team
NNPI
Naval Nuclear Propulsion Information
NNWS Nonnuclear Weapon State
NSA
National Security Agency
NSI
National Security Information
NV
Nevada Operations Office
OMA
Office of Military Application
OPSEC
Operations Security
RD
Restricted Data
RDD
Radiation Dispersal Device
RF
Radio Frequency
RIS
Reporting Identification Symbol
RPM
Revolutions Per Minute
SANDS
Surveillance Accident Nuclear Detection System
SNM
Special Nuclear Material
SOP
Standard Operating Procedures
SSR
Safe Secure Rail
SST
Safe Secure Trailers
TSCM
Technical Surveillance Countermeasures
TSD
Transportation Safeguards Division
TSS
Transportation Safeguards System
U.K.
United Kingdom
XAD
Exempt from Automatic Declassification