8a. Unclassified. Basic theory of hydrodynamics, radiation transport, and the coupling of the two (radiation hydrodynamics) when not applied to the design of nuclear explosive devices.
8b. Classified. Theoretical and experimental work on hydrodynamics, radiation transport, and the coupling of the two (radiation hydrodynamics) when nuclear weapon design interest is revealed or when important to nuclear weapon design.
9a. Unclassified. General analytical theory of interface instabilities for both compressible and incompressible fluids including the effects of magnetic fields.
9b. Classified. Methods of calculating the mixing of materials in weapons and the calculations themselves.
10a Transport theory, methods and codes (except see 10b and following section).
10b. Classified. Transport computer codes authoritatively identified as used or useful for nuclear weapon design.
11a. Unclassified. Plasma physics, as such, and its application in unclassified programs such as magnetic fusion energy, astrophysics, and geophysics.
11b. Classified. Investigations in plasma physics that reveal classified weapon design information.
12a. Unclassified. Computational techniques not associated with weapon design.
12b. Classified. All descriptions (except the name) of computer codes developed or used for nuclear weapon design.
13a. Unclassified. That multi-dimensional hydrodynamics, radiation transport, and TN fusion are used in some unspecified weapon design computer codes.
14a. Unclassified. The names of codes used for weapon design.
14b. Classified. Fact that an unclassified code is used or useful for nuclear weapon design.
15a. Unclassified. Computer codes developed for unclassified programs and their results which do not reveal classified information (e.g., classified design information or material properties such as EOS or opacities.)
15b. Classified. Computer codes or their results which reveal classified material properties (e.g., EOS, opacities) or design information.
In this context, design information means any item of information that is either necessary for the construction of a device or contributes to an understanding of its functioning.
1a. Unclassified. Existence of unspecified nuclear explosive devices employing the following declassified concepts, and the concepts themselves, but without elaboration: (1) gun-assembly (GA); (2) implosion assembly (IA) by means of lensed high explosive (HE) systems; (3) use of DT gas boosting in HE implosion-assembled weapons; (4) use of internal or external initiators (neutron generators) to initiate a chain reaction in a nuclear explosive device; (5) multiple yields; (6) use of energy from a fission trigger (the primary) to produce x-rays which are confined by an radiation case and transported to implode and ignite a physically separate secondary stage, and (7) generic temperatures within weapons of over 10 keV, (i.e., 10{sup 8}K) and pressures over 10 million atmospheres.
1b. Classified. Qualitative and quantitative descriptions, in the context of nuclear weapons, of physical processes pertinent to the functioning of nuclear weapons; e.g., energy transport processes, amounts and modes of compression, internal temperatures and pressures, and details of methods of boosting.
2a. Unclassified. Designation of specific stockpile fission weapons as either gun-assembled (GA) or implosion assembled (IA).
2b. Classified. Information describing the physical arrangements, masses, shapes, and dimensions of materials, etc., suitable for use in nuclear weapons (with no exception even for primitive or obsolete weapons).
3a. Unclassified. Fact of use of U-233, U-235, or Pu in specified IA weapons.
4a. Unclassified. Fact of use of DT gas boosting in specified present stockpile IA weapons.
4b. Classified. Design constraints on boosting.
5a. Unclassified. Descriptions and mode of operation of nuclear explosive devices and their outputs and effects that have been declassified, such as those described in official publications dealing with this subject.
5b. Classified. Information concerning the design or mode of operation of nuclear explosive devices, except general information which has been declassified.
6a. Unclassified. Fact that unspecified IA fission weapons have diameters down to 6 inches and masses down to 50 lbs. and that unspecified TN weapons have diameters down to 8 in. and masses down to 150 lbs.
7a. Unclassified. Fact that, hypothetically, 4 kg of Pu or U-233 is enough for a nuclear explosive device.
8a. Unclassified. External observable features of stockpile weapons systems such as overall dimensions and approximate weight.
9a. Unclassified. Fact that specified U.S. weapons use insensitive high explosive and fire resistant pits to lower the risk of accidents. Also, the fact that unspecified weapons may use other unspecified special measures to lower the risk of accidents.
9b. Classified. Identification of other special measures used to lower the risk of accidents.
10a Basic technology and non-weapon specific components of weapon detonation systems or safing, arming, fuzing, and firing (SAFF) systems.
10b. Classified. All other design information about weapon detonation systems or safing, arming, fuzing, and firing (SAFF) systems.
11a. Unclassified. The fact that U.S. weapons are "one-point safe"; i.e., the chance is less than 1 in one million of HE ignition at a single point leading to a nuclear yield greater than 4 lb of HE.
12a. Unclassified. The fact that many U.S. weapons have special use control features to prevent unauthorized use. These include permissive action links (PALs), and disablement systems.
12b. Classified. All other information about use control features.
13a. Unclassified. Yield range of specified stockpile weapons. i.e., sub-kiloton (below 1 kt) , kiloton (1-1000 kt), or megaton range (above 1000 kt).
14a. Unclassified. The fact that the Little Boy device used at Hiroshima was GA, used HEU, and had a yield of about 15 kt.
15a. Unclassified. The fact that the Fatman device used in the Trinity test and at Nagasaki was IA and used alpha-phase plutonium with a natural uranium tamper. It had a yield of about 21 kilotons.
16a. Unclassified. Fact of research on pure fusion weapons.
16b. Classified. Information concerning the design, principles of operation, or status of research on pure fusion weapons.
Classification of some nuclear testing results is necessary to protect information on the design and performance of nuclear explosive devices, as well as weapon effects. Although most information relating to testing procedures at the Nevada Test Site (NTS) could be of interest to other nations, it is impractical to classify certain things, such as preparation and construction necessary for a test event. Yields are usually protected to avoid confirming data potentially useful to adversaries (e.g., teleseismic estimates of yields) that otherwise would not be precise or accurate. Association of certain programs with the NTS is also classified.
1a. Unclassified. In general, the application of standard methods of engineering or scientific techniques to testing (but see topic 1b.)
1b. Classified. Methods or techniques for conducting testing which reveal classified weapon design information.
2a. Unclassified. The total number and the name, date,and location of all U.S. tests.
2b. Classified. Radioactive debris and analysis which reveal classified weapon design information.
3b. Classified. Detailed device performance (e.g., yields, output radiation spectra, and reaction history).
4a. Unclassified. The fact that a successful test was conducted in 1962 which used reactor grade plutonium.
5a. Unclassified. Total yields of nuclear tests which have been specifically declassified (see "Announced United States Nuclear Tests" DOE/NV-209.) This includes all U.S. nuclear tests conducted in the Pacific through 1961 and many other specific tests in the atmosphere, cratering or other tests not designed to be contained, and underground tests.
5b. Classified. All test yields not specifically declassified.
Weapon effects are the phenomena that result from the energy outputs of a nuclear explosion; e.g., blast, shock, prompt and residual radiation, heat, ground motion, and electromagnetic pulse (EMP). Little about weapon effects themselves is of classification concern. However, weapon effects information is classified if it reveals classified weapon design, output, yield, or vulnerability/hardness information. In addition, some effects information related to high altitude phenomenology and radio and radar blackout is also classified. Most unclassified information about the nature of weapon effects and their phenomenology is encompassed in the DOE/DoD publication, "The Effects of Nuclear Weapons," by Glasstone and Dolan (1977).
1a. Unclassified. Generic weapon effects information (including prompt radiation, blast, thermal, fireballs, high altitude phenomenology, ground motion, electromagnetic pulse, etc.) that has been released officially for civil defense or scientific purposes. (But see topics 1b. and 2b.)
1b. Classified. Effects data that reveal classified information about the weapon used as a source or are of strategic or tactical importance (e.g., vulnerability or hardening data).
2a. Unclassified. Qualitative description of x radiation output as a nominal 1-2 keV [NOTE 3] blackbody spectrum.
2b. Classified. The actual quantitative spectrum of neutrons, gammas, or thermal or x radiation emergent from a nuclear weapon.
3a. Unclassified. The optical spectrum of radiation emergent from the surface of a fireball resulting from a surface or low-altitude detonation.
4a. Unclassified. Fact of development and existence of defense systems which employ x radiation, blast, neutrons, or combinations thereof, as kill mechanisms. (But see topic 2b.)
4b. Classified. "Kill" capability against incoming warheads.
5a. Unclassified. Existence of unspecified weapons with tailored x-ray or neutron outputs; e.g., enhanced radiation or suppressed radiation. That certain specified stockpile weapons have a tailored (enhanced radiation or suppressed radiation) output.
5b. Classified. Information on the methods used to accomplish tailored effects.
Vulnerability/hardening is concerned with the effects of nuclear detonations on nuclear weapons and missile systems and the hardening of such systems to these effects.
1a. Unclassified. Existence of a program to harden unspecified nuclear weapons and/or weapons systems against x-ray and neutron effects.
1b. Classified. Information on the level of vulnerability or hardening and the means employed for hardening, for specified or unspecified weapons.
2a. Unclassified. Generalized statements on how hardening may be accomplished in undesignated weapons.
2b. Classified. Identification of a designated nuclear weapon as hardened to a particular effect.
3a. Unclassified. The fact that designated or undesignated nuclear weapons are hardened against the effects of neutrons, gamma and x rays, EMP, thermal radiation, or blast to some unspecified degree.
3b. Classified. Hardening materials and techniques applied to a specified weapon that reveal its vulnerability or hardness level.
1a. Unclassified. Manufacturing techniques or equipment generally.
1b. Classified. Manufacturing techniques or equipment of unique significance to the fabrication of nuclear explosive devices.
2a. Unclassified. Component production rate or quantity information not revealing classified stockpile information.
2b. Classified. Production rates or stockpile quantities: totals or for specified nuclear weapons.
3a. Unclassified. Total number or rate of dismantlement of unspecified weapons, provided classified stockpile information is not revealed.
3b. Classified. Number or rate of dismantlement of specified weapons.
4a. Unclassified. Historic qualitative trends in U.S. stockpile total numbers and total yield or "megatonnage" (no numerical values).
5a. Unclassified. Capability of a site to store or handle nuclear weapons, provided that the presence of weapons is not revealed.
5b. Classified. Location, capacity, and inventory of storage sites and dispositions of deployed weapons.
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