Summary on The Sub-Criticals
by Greg Mello

The U.S. is now fielding a new tactical and strategic nuclear military capability that has already been used to threaten a non- nuclear country. This new capability was certified without nuclear testing, using an existing surrogate testing facility with capabilities much less than those under construction and planned. The weapon was developed and deployed in secret, without public and congressional debate, contrary to domestic and international assurances that no new nuclear weapons were being developed. Other new or "modified" nuclear weapons, earth-penetrating and otherwise, are planned.

B61-11 CONCERNS AND BACKGROUND February 10, 1997

Researching this issue has been a cooperative effort. This summary could not have been written without the help of Bruce Hall at Greenpeace and Stan Norris and Chris Paine of the Natural Resources Defense Council.

Background research on new weapons generally, though not on the B61-11, has been partially supported by Tri-Valley CAREs of Livermore, California.

For further information contact: Greg Mello 505-982-7747


In order to gain support for indefinite extension of the NPT, the United States repeatedly assured the world in April and May of 1995 that it would not continue "vertical proliferation." During these same months the Department of Energy was seeking, and obtaining, approval for a weapon modification with significant new military utility.

Development of this weapon was approved outside the regular budget process and without congressional debate, by means of secret letters to key committee chairmen, raising constitutional questions.

In their efforts to gain acceptance for the advanced surrogate testing of the "science-based stockpile stewardship" program, Clinton Administration officials and laboratory spokespersons have for years assured a skeptical public that no new nuclear weapons would be developed or built. At the very same time, secret development of this provocative weapon was being requested by the Pentagon and carried out by the DOE in complete secrecy.

The DOE claims that this weapon, with its unique new military characteristics, is not a new weapon but rather a minor modification of an existing weapon. Lab spokespersons admit that other "modifications" are now in the works or planed for the future. What are these?

The current B61 modification allegedly involves only the nonnuclear components of the bomb (notwithstanding months of effort at Los Alamos). Yet the labs maintain that in the future, modifications to the nuclear components will definitely be made and certified as well, using computer simulations and surrogate tests. Since none of the modifications can be explosively proof-tested, why won't "confidence" in the reliability of U.S. nuclear weapons decrease under these plans? Unfortunately, allowing such changes to be made will likely result, over time, in calls for the resumption of nuclear testing.

Continued modification of the U.S. stockpile is expensive. While this particular project may or may not be expensive in itself, the DOE's $3 billion construction plans to build new nuclear test simulators, plus its planned Cold-War-level nuclear weapons program funding, is largely driven by the proclaimed "need" to maintain the capability to develop new warheads and bombs. These DOE expenses, it must be said, are just a fraction of the $34 billion spent annually by the U.S. to field and maintain its nuclear arsenal.

For these reasons and others, new or "modified" nuclear weapons like the B61-11 are not in the security interests of the United States. On the contrary, it is in our manifest interest to get rid of such weapons as fast as possible and to quit their further legitimization, as former STRATCOM commander Lee Butler and others have recently said.[Footnote: See, for example, R. Jeffrey Smith, "Retired Nuclear Warrior Sounds Alarm on Weapons," Washington Post, December 4, 1996.]

Development, Testing, and Deployment

The B61-11 story came to light in slow installments.

In early September 1995, the U.S. Department of Energy (DOE) and its three nuclear weapons labs released a revised version of a report about their nuclear stockpile surveillance program. This report contained a footnote on page 11:
A modification of the B61 is expected to replace the B53 by the year 2000. Since this modification of the B61 is not currently in the stockpile, there is no Stockpile Evaluation data for it. The B61-7 data can be used to represent this weapon.[Footnote: Kent Johnson et. al., 1995, "Stockpile Surveillance: Past and Future," DOE Defense Programs. This is the text of the report given to Hisham Zerriffi of the Institute for Energy and Environmental Research on September 13, 1995 at Los Alamos. The footnote was abridged in subsequent editions of the report.]

Dr. Don Wolkerstorfer, Above-Ground Experiments I (AGEX I) Program Manager, Nuclear Weapons Technology Program, Los Alamos National Laboratory (LANL), had shed light on this modification in a broadcast debate:

The services are looking at redeploying an existing weapon in such an earth penetrating warhead to address hardened targets, that's exactly right. The hope is to replace the high yield B53, which has some safety problems...[Footnote: Broadcast by radio station KSFR in Santa Fe, NM on July 18, 1995]

For reference, the B53 is a 9-megaton gravity bomb first placed in service in 1960. Retirement of early versions began in 1967, but later versions of this bomb remained in the arsenal until 1987, when retirements were halted and retired (but still assembled) bombs were brought back into the active stockpile. The B53 can be a surface-burst but not an earth-penetrating weapon.[Footnote: History from Chuck Hansen, U.S. Nuclear Weapons: The Secret History, Orion Books, 1988.] It lacks complete electrical safety. There are thought to be 50 of these weapons in the stockpile.[Footnote: Robert Norris and William Arkin, "Nuclear Notebook," Bulletin of the Atomic Scientists, July/August 1996, p. 61-63.]

The B61-7 is a more recent strategic bomb in the stockpile. It has a selectable yield of 10 to about 340 kilotons. The original B61-1 first entered the stockpile in 1968; the "mod 7" was first placed in service in 1985. The B61-7 can be fuzed for air or surface burst and has "a hardened ground-penetrator nose" with a retarded contact burst fuzing option. It can be dropped with or without a parachute. There are thought to be 750 of these bombs in the active stockpile, along with about 600 B61-3, -4, and -10 tactical bombs.[Footnote: Quote and descriptive information in this paragraph are from Hansen, op. cit.; stockpile numbers are from Norris and Arkin, op. cit.] The B61 family of weapons can be configured with a wide variety of yields, including 0.3, 1.5, 5, 10, 45, 60, 60, 80, 170, and 340 kilotons.[Footnote: Norris and Arkin, op. cit.; the largest yield is from Arkin, personal communication, 1/14/97.}

In recent years, many military strategists have advocated the deployment and use of very small tactical nuclear weapons against Third-World adversaries, especially in earth-penetrating roles.[Footnote: For example, see the following Strategic Review articles: Thomas Dowler and Joseph Howard, "Countering the Threat of the Well-Armed Tyrant: A Modest Proposal for Small Nuclear Weapons," (Fall 1991) and, by the same authors, "Stability in a Proliferated World" (Spring 1995); also Philip Ritcheson, "Proliferation and the Challenge to Deterrence" (Spring 1995). Dowler and Howard work at Los Alamos.

Important reviews of the post-Cold-War shift in U.S. nuclear targeting plans can be found in Hans Kristensen and Joshua Handler, "Changing Targets: Nuclear Doctrine from the Cold War to the Third World," Greenpeace International, January 1995; and William Arkin, "Nuclear Agnosticism When Real Values Are Needed: Nuclear Policy in the Clinton Administration," Federation of American Scientists Public Interest Report, September/October 1994.] The two lowest yields of the B61 family lie well within this so-called "mininuke" range.

The percent of blast energy converted into shock waves in the earth is extremely sensitive to the depth of the blast. Thus even a small increase in earth penetrating capability can greatly affect the military utility of a nuclear weapon to hold deeply buried and hardened targets at risk. Hardening of the B61 to allow very high altitude release, with consequent high velocity ground impact, apparently provides such an increase in capability.

In September 1995, when the B61-11 story broke, Lab spokespersons said the development of the modified warhead would take two years, and would be done primarily at Sandia. Development, but allegedly not deployment, had been approved at that time.[Footnote: "Old nuclear warheads get new life," Jonathan Weisman, Tri-Valley Herald (Livermore, CA), 9/21/95.] DOE's classified request to reprogram $3.3 million in funds within its Atomic Energy Defense Weapons Activities account was dated April 18, 1995 and was sent to the following committees:

House Energy and Water Development Appropriations Subcommittee (approval from Tom Bevill and John Myers, 5/15/95);

House National Security Committee (approval from Floyd Spence and Ronald Dellums, 6/29/95);

Senate Armed Services Committee (approval from Strom Thurmond, 7/19/95); and

Senate Energy and Water Development Appropriations Subcommittee (approval from Pete Domenici, 6/12/95).[Footnote: Approval letters are on file at DOE Defense Programs.]

Not long after the existence of the weapon became public, Dr. Harold Smith, then Assistant to the Secretary of Defense for Atomic Energy, requested at the Nuclear Weapons Council Standing Safety Committee meeting of November 15, 1995, that the above schedule be accelerated, with the First Production Unit (FPU) of the B61-11 be delivered "as soon as possible, with a goal of December 31, 1996."[Footnote: Memorandum from Thomas Seitz, Acting Deputy Assistant Secretary for Military Application (DASMA) and Stockpile Support to weapons program administrators at Sandia and Los Alamos national laboratories, November 17, 1995, requesting response as to feasibility of earlier FPU delivery date. Dr. Smith followed up his request at the November 15 meeting with a letter to Mr. Seitz on November 21.]

The response from the nuclear labs, here from Los Alamos, was positive:

The B61-11 modification project...was originally scheduled for completion by August 1997; however, DoD requested that we advance the completion date to December 1996. NWT [the Nuclear Weapons Technology program] is committed to meeting the aggressive schedule, and a significant reprogramming of resources has allowed us to accelerate our progress...Full-scale testing, led by Manny Martinez, is in progress, and three successful test drops took place in Alaska on February 28...[Footnote: Los Alamos National Laboratory, Weapons Insider, April 1996, pp. 1-2.]

In August 1996, LANL provided an update on the project, along with some additional details.

The essence of the modification is a field changeout of the weapon's case to provide an earth-penetration capability. The B61's inherent ability to perform this mission was demonstrated in Nevada almost a decade ago...The engineering and nuclear certification activities are in high gear. Hydrotest Shot 3574 in September [at LANL's newly-upgraded PHERMEX surrogate testing facility] will be the basis for assuring that the underground environment does not adversely affect nuclear performance. Full-scale penetration tests of real and high-fidelity mock hardware are being conducted at the Tonopah Test Range in Nevada...We are committed to delivering the First Production Unit kits by the end of the calendar year. [emphasis added][Footnote: Los Alamos National Laboratory, Weapons Insider, August 1996, pp. 2- 3.]

Note that the "nuclear certification" mentioned is being done on the basis of hydrodynamic testing and computer modeling, without underground nuclear testing. The reference to earlier B61 earth- penetration tests is discussed below.

Two months later, Steven Younger, Program Director of NWT, encouraged his troops with this message:

As I see it, our highest priority over the next several months is the B61 Mod 11, and the Air Force is anxiously awaiting this system....The project is proceeding at a very fast pace, and almost every division associated with our Program is contributing to this important work.[Footnote: Los Alamos National Laboratory, Weapons Insider, October 1996, p. 1.]

These goals have now been achieved.

The last in a series of B61-11 full-scale drop tests, prior to the Major Assembly Release (MAR), was conducted at the Tonopah Test Range on November 20, 1996. More than 60 people from throughout the complex were on hand to observe the early morning drops. Three units were dropped from a B2-A aircraft, two units from about 6900 feet above ground level (AGL) and a third from about 25,700 feet AGL. Prior to November's tests, we had demonstrated compatibility with the F-16 and the B-1A aircraft...All objectives with the exception of recording the strain measurements were met...Another attempt to record strain measurements will be made in the upcoming test, now scheduled for early April [1997] in Alaska. [emphasis added][Footnote: Los Alamos National Laboratory, Weapons Insider, January/February 1997, pp. 1-2.]

Note that the new weapon has been tested for delivery with a variety of aircraft, including the F-16, a tactical delivery system, marking a considerable shift in application from the B53.

Inquiries with DOE have confirmed that deployment is indeed now underway. The "front" components of the new weapon are being or were made at the Y-12 Plant on the Oak Ridge Reservation in Tennessee, with "tail" (read: arming and fuzing?) components made at the Kansas City Plant in Missouri. The decision to retire the B53 is now "pending." The location(s) where the modifications are being done is classified, as well as the number of weapons being converted.[Footnote: John Ventura, DOE Defense Programs, telephone conversation, January 29, 1997.]

Even before Deployment, the B61-11 Caused Collateral Damage
Why did Harold Smith insist that the deployment of the B61-11 be rushed? Isn't the purpose of the new bomb just what DOE has said, namely to replace the aging and "unsafe" 9-megaton B53 in its role of excavating deeply-buried Russian command bunkers in the event of a global nuclear apocalypse? If so, why the rush?

The reason for the November 1996 schedule change became clear the following April, when a series of Pentagon spokespersons, including Dr. Smith, used the imminent deployment of the B61-11 to threaten Libya.

At a press conference on April 23, Dr. Smith outlined U.S. conventional and nuclear capability for destroying a suspected Libyan chemical weapons factory, under construction underground at Tarhunah, 40 miles southeast of Tripoli.

Dr. Smith explained that, at present, the United States has no conventional weapon capable of destroying the plant from the air, and such a weapon could not be ready in less than two years. Smith went on to tell reporters that an earth-penetrating B61 nuclear bomb, now under preparation, could take out the plant. The new bomb would be ready for possible use by the end of this year, Smith said, before the expected completion date of the factory.

Since 1978, the United States has assured the world that it would never use nuclear weapons against nonnuclear countries who signed the Nuclear Nonproliferation Treaty (NPT), unless a country were allied in aggression with a nuclear weapon state. On April 5, 1995, President Clinton reaffirmed this policy, which has been a cornerstone of U.S. nonproliferation efforts, and an important part of the offer the U.S. made to skittish nonnuclear states to induce them to vote for the indefinite renewal of the NPT.

On April 11, just 12 days before Dr. Smith's announcement, and after an interagency struggle that pitted the Pentagon against the State Department, the U.S. signed the African Nuclear Weapons Free Zone Treaty in Cairo. In this treaty the U.S. pledged not to use or threaten to use a nuclear weapon in Africa against any of the nearly 50 signatory states, including Libya.

U.S. negative assurance pledges (pledges of "no first use" except under the circumstances mentioned) were thus clearly devalued by the Pentagon's threat, which marked a shift in explicit U.S. nuclear policy. That shift was to openly include the possibility of preemptive strikes against weapons of mass destruction (WMD) capabilities, in addition to the possibility of a nuclear response to WMD use. Such a posture, if allowed to stand, would have been unprecedented in nuclear history.

The announcement by Dr. Smith, which had been joined by statements from Secretary of Defense William Perry and others, sent shock waves through diplomatic circles. A retraction was given by Pentagon spokesman Kenneth Bacon at a press conference on May 7.[Footnote: Charles Aldinger (Reuters), 5/7/96, "U.S. rules out nuclear arms against Libya plant."] B61-11 development continued on the previously-accelerated schedule, however.

Finally, and probably coincidentally, the cover photograph of the December 1996 issue of Air Force Magazine shows an F-16 parked in front of what is clearly a nuclear weapons storage facility at Aviano Air Force Base, Italy, about 900 miles from Libya.[Footnote: Personal communication, Stan Norris.]

More Earth Penetrators, Nuclear and Otherwise, to Come

From the DOE perspective, the B61-11 is a "modification" to the B61-7 strategic gravity bomb. As military capability, however, the B61-11 provides something new--else why deploy it? That deployment appears to be at odds with the statement of U.S. Arms Control and Disarmament Agency (ACDA) Director John Holum in Geneva three months before, where, in the context of comprehensive test ban treaty (CTBT) negotiations, Holum said that the United States would not develop new nuclear weapons.

That being said, the B61-11 is not the only new nuclear weapon, and not even the only new earth-penetrating nuclear weapon, planned for the stockpile. In Kenneth Bacon's DoD press briefing in the afternoon of April 23, the following colloquy occurred:

KB:...We are now working on a series of weapons--both nuclear and conventional--to deal with deeply buried targets, working on improving weapons we already had...

Q:...Are we working on new--you said nuclear and non- nuclear--and I want it to be very clear. Are we working new nuclear weapons or modifying and improving existing nuclear weapons?

KB: Yes.

Q: Which is that? New or improved?

KB: We are modifying existing ones [note plural]. As I said, this is not a new threat.

Q:...why is the Secretary not considering, or is he considering, anything specific to deal with these targets which are much, much deeper than anything we've ever addressed in the last 20 years?

KB: We are.

Q: You're doing what?

KB: We are looking at ways to deal with ever deeper targets. [emphasis added]

In order to address deeper targets at a given yield, deeper earth penetration and hence higher speed are needed. Such weapons have been under development for many years. A prototype W86 warhead was developed by LANL for the Pershing II missile but was canceled in 1980 in favor of a Livermore design.[Footnote: See photograph and caption in Cochran, et. al., Nuclear Weapons Databook, Vol. II, U.S. Nuclear Warhead Production, Natural Resources Defense Council, p. 37.] There were underground nuclear tests of earth penetrator warheads in 1988 and 1989 of both "interim" and "strategic" designs;" the former was in fact based on the B61 and was called the W61.[Footnote: Source anonymous.]

To pick one nuclear command, it can only be assumed that the U.S. Navy has not changed its previous advocacy of "a wider range of targeting options for maintaining a credible nuclear deterrent in the new world order," in which low-yield earth-penetrating warheads are an explicit part of efforts to expand Trident D-5 options.[Footnote: Kristensen and Handler, op. cit., p. 9, quoting "STRATPLAN 2010," June 1992, U.S. Navy.]

The Los Alamos Study Group is compiling what is known about other new proposed new and "modified" nuclear weapons. This work has been supported by Tri-Valley CAREs of Livermore, California. Los Alamos Study Group
212 E. Marcy St. Suite 7
Santa Fe, New Mexico 87501
505-982-7747 voice
505-982-8502 fax

More information --

Physicians for Social Responsibility, February 2, 1997: "Issue Brief: Unresolved New Nuclear Weapons Development Issues"
Albuquerque Journal, February 11, 1997: "CRITICS CHALLENGE N-BOMB ADDITION" (forwarded by Greenpeace)
Sandia Labs, March 6, 1997: "More Penetrating developments" (forwarded by Greenpeace)

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