U.S. Nuclear Weapons Stockpile, July 1996

 U.S. nuclear forces after START II (2003) table

Operational U.S. nuclear weapons stockpile, July 1996 table


Little change occurred over the year in the size of the U.S. nuclear stockpile, though we have new understandings of its future direction and composition. Regardless of whether START II is fully implemented, the total number of warheads in all categories will remain between 9,500 and 10,000. If START II is implemented and strategic nuclear force reductions are made, the only difference will be in the ratio of warheads deployed to those in a less-ready condition.

Warheads now fall into one of four categories: (1) those assigned to active delivery systems; (2) "hedge" warheads in storage that could be redeployed quickly to increase forces back to START I levels; (3) "inactive reserve" warheads in a less-ready condition that could be used to replace stockpiled weapons withdrawn for testing and as a source of spare parts; and (4) retired warheads awaiting final disassembly at Pantex in Texas.

The "enduring" stockpile. The operational U.S. nuclear stockpile-those warheads that accompany deployed forces-has now stabilized, and without progress on START II it is unlikely to decline any further. The table on page 63 is our estimate of the composition of the current operational stockpile of approximately 9,250 warheads. Assuming that START I and II will be fully implemented, the operational stockpile in the year 2003 is scheduled to be 5,000 warheads, composed of some 3,500 strategic and 950 non-strategic weapons, plus about 500 spares (see the table at right). This total will be split in half between the air force and the navy, with 79 percent overall in strategic forces.

Supplementing those in the field will be another 2,500 warheads in the "hedge," a category created by the 1994 Nuclear Posture Review. These warheads will be removed from delivery systems under the requirements of the START treaties, but could be redeployed onto missiles and aircraft. The hedge is discussed in greater detail in the July/August 1995 Nuclear Notebook.

When he signed the Nuclear Weapons Stockpile Memorandum on February 23, 1996, President Bill Clinton directed that the Defense Department not make any unilateral reductions beyond those required by START I.

The inactive stockpile. Another set of warheads are in the inactive reserve. They are stored in military depots and thus not scheduled to be disassembled at the Pantex plant. If and when START II is implemented, the inactive stockpile will also contain some warheads now in the operational stockpile that will be withdrawn. We estimate that the inactive stockpile will eventually contain 2,500 to 3,000 warheads.

The requirement for an inactive stockpile stems from a U.S. policy that warheads in the enduring stockpile be maintained with sufficient tritium to achieve their design yield at all times. This is not the case with warheads in the inactive reserve. While they remain intact, their tritium is removed. Thus the inactive reserve warheads require more time to be readied for redeployment. The W84 warheads retrieved from the eliminated ground-launched cruise missile are the only type now in the inactive stockpile, but others are in transition to it. See the table below.

Retired warheads awaiting dismantlement. In the fourth category are "retired" warheads removed from operational service that are awaiting their turn on the disassembly line. The warheads to be disassembled over the next three years (through mid-1999) include the W79 army artillery warheads, the W55 for the SUBROC (submarine rocket), the W69 for the SRAM-A (short-range attack missile), the W56 Minuteman II warhead, and B61 Mod-2 and Mod-5 bombs. The W48 artillery shell (March 1996), the B61 Mod-0 bomb (June 1996), and the W70 for the Lance (February 1996) are warheads for which disassembly has been completed, or is nearly complete.

In October 1992, the Energy Department set a dismantlement goal of 2,000 warheads per year. It never reached that level. The workload goal decreased with the creation of the hedge and inactive reserve-so much so that under current schedules, Pantex will cease dismantlement work in fiscal 1999.

The actual and projected rates of dismantlement and disposal are listed below:

 Year
Warheads
1990
1,154
1991
1,595
1992
1,856*
1993
1,556
1994
1,369
1995
1,393
1996
1,166
1997
1,221
1998
1,084
1999
415
* Includes 553 uranium-only W33 warheads dismantled at the Y-12 plant at Oak Ridge, Tenn.

 

On January 19, 1994, Energy announced a decision to increase plutonium "pit" storage at the Pantex plant from about 6,000 to some 12,000 to accommodate dismantled weapons. According to a Pantex spokesman, as of April 30, 1996, there were 8,874 pits in storage. Under current schedules, by September 30, 1999, when dismantlements end, there will be approximately 12,000 pits in storage in Texas.

After the backlog of retired warheads are disposed of, Pantex will continue to perform evaluation work on a small number of warheads each year. During evaluation some warheads are not, or cannot, be put back together and they are disposed of. Others are evaluated, then reassembled and returned to the stockpile. The United States uses approximately 60 warheads per year in evaluation and disposal. In the 1980s, when the stockpile was larger and there were more types, twice as many warheads on average were disposed of during evaluation. In the evaluation/reassembly category, the average number during the 1990s is 69 per year; in the 1980s it was 210 per year.

The post–START II stockpile- operational, hedge, and inactive reserve-will comprise ten warhead types, with Los Alamos responsible for the stewardship of six types (B53, B61, W76, W78, W80, W88) and Lawrence Livermore responsible for the stewardship of four (W62, W84, W87, B83). Some types will be in more than one category, while others will be in only one.

Development of new capabilities. In the near-term, the laboratories are working on alterations to the B61 bomb, a B83 quality improvement program, a W76 neutron generator replacement, a W76 tritium reservoir replacement, a W87 life-extension program, W88 pit rebuilding, and the B61/B83 common radar program.

Last September, the Los Alamos Study Group, a Santa Fe-based watchdog, revealed that work was being done toward modifying a B61 bomb for improved earth-penetrating capability. The U.S. government went to great pains at the time to insist that the bomb, if deployed, would not constitute a new nuclear weapon, and public talk of the modification ceased.

But this April, Defense Department spokesman Kenneth Bacon confirmed that the United States was modifying existing bombs (presumably the B61) to attack deeply buried targets. Admittedly, this is in lieu of a new earth-penetration warhead, long on the design boards of nuclear scientists. It also was discovered that in fiscal 1995, the air force undertook a second program to develop a B61 Mod-11 nuclear bomb- an improved older B61-customized for strategic bombers.

In 1995, the air force also initiated the Single Reentry Vehicle (SRV) program. The program's purpose is to coordinate air force and navy reentry vehicle (RV) research, to monitor performance of existing ballistic missile reentry vehicles, and to design an improved RV for the future. In the words of Paul Kaminski, undersecretary of Defense for Acquisitions and Technology, such a new system would, "deal with new classes of targets-i.e., deep, hardened and/or relocatable targets." With MX W87 warheads already in hand, the air force apparently does not seem interested in designing a new warhead for this prospective RV, yet the May 9 issue of Inside the Pentagon revealed navy interest in investigating a back-up warhead design for its SLBMs.

A number of special studies also continue to be conducted by the Energy Department and the Defense Department, particularly for newer designs that might improve long-term safety (like an all-uranium warhead) or "tailored" effects weapons with specialized war-fighting missions. For instance, the Phase 2 study for the high-powered radio-frequency warhead was completed in 1995, and the design was fully documented and placed on the shelf. Despite the demise of the so-called "mini-nukes" program, various warhead ideas to counter weapons of mass destruction are also being investigated by the nuclear laboratories and the air force.

Continuing nuclear costs. Despite no new nuclear warhead production since 1990, delivery of the eighteenth and final Trident submarine in 1997, and completion of B-2 bomber production in 1998, the cost of modernizing and maintaining the nuclear force continues to be sizable. Energy is scheduled to spend $20 billion in the Stockpile Stewardship Program over the next five years, an amount that exceeds the average annual level of Cold War spending on nuclear warhead research, development, testing, and production. Meanwhile, Defense has undertaken a $4.5 billion D5 backfit program to equip 14 ballistic missile submarines, instead of only 10, with Trident II missiles, claiming it must maintain an industrial base to build ballistic missiles.

Operation and maintenance costs of the ICBM force, including procurement of minor missile-related items, is estimated at $5.7 billion through the life of the current force (until 2020), according to the proposed 1997 budget. Pentagon spending on more major upgrades and replacement programs adds up to approximately $10 billion (see below). This does not count procurement of such systems as a new RV, mentioned above, or new strategic command, control, and communications equipment. Here are some of the programs and their costs:

Trident D5 Navigation Upgrade, $250 million; Minuteman III Propulsion Replacement, $2.9 billion; Minuteman Guidance Replacement, $1.6 billion; Air Force/Navy RV Upgrade Studies, $250 million; ICBM and SLBM day-to-day upkeep, $3 billion; B-2 day-to-day upkeep, $1 billion.

(The last three items only show costs through the end of the current five-year defense plan.)

Referring to these ongoing efforts, air force Gen. Eugene E. Habiger, commander of U.S. Strategic Command, testified before the Senate in March that, "other sustainment and modernization programs in each leg of the Triad will be needed to preserve our technological edge over the next 30 years."

U.S. nuclear forces after START II, 2003
      Warhead type Warhead number
 Operational
 Strategic forces        
 ICBMs 500 Minuteman II W87-0, W78, W62 500
SLBMs 336 Trident II on 14 SSBNs X5 W76
W88		 1,280
400
 Bombers 21
32
32		 B-2A Spirit,
B-52H x 20, }
B-52 x 12		 B53, B61-7, -11
B83
W80-1		 400
500
400*
Subtotal
~3,500
Non-strategic forces        
Sea-launched cruise missiles    W80-0 350
Air force tactical bombs    B61-3, -4, -10 600
Subtotal
950
Total operational warheads 5,000**
"Hedge"
ICBM warheads (W62, W78) to upload Minuteman IIIs 2,500
SLBM warheads (W76) to upload Trident missiles
Bomber weapons for B-1 and B-52H
Inactive (tritium removed but intact)
 B61 bombs, W62 ICBM warheads, W76 SLBM warheads, W80 ALCM warheads, and W84 GLCM warheads  2,500
Grand Total ~10,000

*The advanced cruise missile (ACM) is currently planned to be carried only by the B-52.
**Number includes spares for routine maintenance.

 

Operational U.S. nuclear weapons stockpile, July 1996

Warhead/weapon First produced Yield (kilotons) User Number (warheads) Comments
Bombs
B53-1 8/62 9,000 AF 50 Will be retained.
B61 Strategic 10/66 10 to 300 AF 750 Mod-7 is the only version in the strategic stockpile It is a converted Mod-1 with CAT D PAL and IHE.
B83/B83-1 6/83 low to 1,200 AF 650 Strategic bomb replaced B28, B43, and B53.
Submarine-launched ballistic missiles
W76/Trident IC4 6/78 100 N 3,000 Over 1,500 W76 warheads from retired Trident I SLBMs are available for Atlantic Fleet Trident II SLBMs. 1,000 less will be needed if START II is implemented.
W88/Trident II D5 9/88 475 N 400 Warheads will supplement the W76 warhead and arm Atlantic Fleet Trident II SSBNs.
Intercontinental ballistic missiles
W62/Minuteman III 3/70 170 AF 610 In a reversal from the Nuclear Posture Review, W62 warheads will be retained.
W78/Minuteman III 8/79  335 AF 920 Some may be used to arm single-warhead Minuteman IIIs.
W87-0/MX 4/86 300 AF 525 Missile will be retired and W87 used for a single-warhead Minuteman III if START II is implemented.
Air-launched cruise missiles
W80/-1ACM ?/90 5 and 150 AF 400 Operational in 1991. Original program of 1,461 ACMs has been cut to 460. Uses W80 warheads from ALCMs.
W80-1/ALCM 12/81 5 and 150 AF 1,000 Some 50 exist as conventional versions (CALCM). It is planned that more ALCMs will be converted to CALCMs. During the Persian Gulf War, 39 CALCMs were launched. Some 700 ALCMs are in storage with their warheads removed. W80s are used to arm ACMs.
Non-strategic forces
 B61 tactical bomb 3/75 0.3 to 170 AF, NATO 600 Mods-3, -4, -10. The Mod-10 is a converted W85 Pershing II warhead. All have CAT F PALs and IHE. Each Mod has four yield options: The B61-3 (0.3, 1.5, 60, and 170 kilotons), the B61-4 (0.3, 1.5, 10, and 45 kilotons), and the B61-10 (0.3, 5, 10, and 80 kilotons).
W80-0/SLCM 12/83 5 and 150 N 350 Nuclear SLCMs now stored ashore. Original program of 758 for 200 ships and submarines reduced to 367 SLCMs, now for 25 Sturgeon-class, 62 Los Angeles-class, and 3 Seawolf-class attack submarines.

AF: Air Force; N: Navy; NATO: non-U.S. delivery system; ACM--advanced cruise missile; ALCM--air-launched cruise missile; IHE--insensitive high explosive; PAL--permissive action link; SLBM--submarine-launched ballistic missile; SLCM--sea-launched cruise missile; SSBN--nuclear-powered ballistic missile submarine. In weapons nomenclature B stands for "bomb" and W for "warhead." The number following the letter indicates the order in which it was introduced into the stockpile; for example, W88 followed W87.


Nuclear Notebook is prepared by Robert S. Norris and William M. Arkin of the Natural Resources Defense Council. Inquiries should be directed to: NRDC, 1200 New York Avenue, N.W., Suite 400, Washington, D.C., 20005; 202-289-6868.