STRATDELA Special Issue #5: NATO Nuclear Sharing
These days there is a lot of talk about possible arrival of Russian substrategic nuclear weapons to Belarus. Good time to think about other tactical nukes in Europe, before, or rather after, it was cool.
The NATO Nuclear sharing programme, or more accurately the relevant practices, is a well-known topic — it used to be heavily criticised from Moscow and a cause for protests and political debates in Europe. Things are a bit different now, but, anyway, its origins and status are not that familiar for all commentators. STRATDELA will try to fix this.
Origins
It is rather difficult to identify a specific decision that led to the creation of Nuclear Sharing in NATO. It was developed in the 1950s within the framework of NATO operational plans creation. In particular, it seemed to be an optimal way to increase combat effectiveness of the armed forces of the US European allies and thus to reduce the American military presence on the continent to reasonable limits in the conditions when the military capability of the Soviet Army and Warsaw Pact troops was greatly overestimated.
Moreover, even if limited, the possibility to use American nuclear weapons helped to keep the allies away from their own nuclear programmes, which, if implemented, would have made them more independent and would have facilitated the spread of nuclear weapons around the world. It should be remembered that at that time not only France, which had implemented it, but also West Germany, Italy, Sweden and others were seriously considering plans to develop nuclear weapons. Since nuclear weapons were quite lightly regarded as a more ore less normal weapon for battlefield use, it quite rightly seemed that without them it would be impossible to provide defense against a “nuclear” army.
Perhaps one can take the summer of 1957 as a starting point, when the US publicly pledged to deploy a significant arsenal of nuclear weapons on the continent . The “Sputnik effect” dramatically increased the fears of European countries that, under the threat of a missile attack by the USSR, the US might not stand up to defend its allies. To reassure the allies, the Eisenhower administration authorized the deployment of intermediate-range ballistic missiles and large numbers of gravity bombs, as well as other tactical nuclear weapons (primarily nuclear warheads for tactical missiles). US intermediate-range Thor missiles were deployed in Britain as part of Project Emily, and Jupiter missiles were deployed in Italy and Turkey. Members of the host nations’ air forces were trained to operate the missiles, and the missiles were formally theirs — the Americans retained formal control over the warheads. The deployment of Thor and Jupiter was seen as a temporary measure, as the missiles on fixed, unprotected launchers were obviously highly vulnerable. As a longer term solution, ideas under consideration included mobile launchers (wheeled or on railroad platforms), deployment on surface missile ships disguised as transport vessels (Multilateral Force, MLF) and even Project Iceworm, a huge tunnel system with missile silos under the Greenland glaciers.
For different reasons, but none of those materialized. In the 1960s the interest of the US and its allies in mass arming everyone around with nuclear strike weapons somewhat waned. Sometimes this is attributed to the Cuban Missile Crisis. Also, the NPT was created, and many countries of the alliance began to join it, which was supported by the US. Washington proceeded from the premise that the treaty did not affect the mutual obligations of the states that already existed at the time of its initiation, and insisted upon it to this day. The USSR seems to have been happy with such state of affairs, perhaps because it pursued a similar policy in the CFE, albeit on a much smaller scale. However, Moscow has always kept the nuclear charges under stricter, not formal, control.
As a result, NATO nuclear sharing was limited to warheads for operational-tactical missiles, surface-to-air missiles, air-to-air missiles and tactical bombs. The latter became the main part of the “common nuclear arsenal”, after the early 1990s the only one, and from now on we will speak only about it (although perhaps we might address the “exotics” in another Special Issue).
A system that has been originally put in place is still in use today — US nuclear bombs with maintenance personnel were deployed at national air force bases where units with carriers (mainly fighter-bombers) were deployed, and local pilots and ground personnel were trained in using the bombs. The initial carrier types were, for example, the F-100D “Super Sabre” (e.g. the French Air Force prior to its withdrawal from the NATO military in 1967, due to withdrawal from the NATO military structures) and the “Canberra” in the RAF (units deployed in West Germany from 1960 to 1972; interestingly, as conventional bombers Canberra stopped home operations in 1961, only nuclear forward-deployed units remained). Interestingly, the RAF also deployed British tactical nuclear bombs (e.g. WE177) on RAF airbases in West Germany, up until the mid-1990s. Perhaps for a brief initial period, F-84F Thunderstreak was considered by the Luftwaffe as a carrier.
However, since the first half of the 1960s F-104 “Starfighter” of various modifications, primarily F-104G, originally built for the Luftwaffe, and its derivatives for other countries became the most common carrier of American tactical nuclear bombs in the NATO Air Force.
The use of the high-altitude air superiority fighter as a low-altitude attack aircraft and regular training in this manner (primarily for nuclear strikes) caused F-104 to have such notorious accidents — where it was not a common practice, for example in the USAF (where F-105 was used for this purpose), the number of “Starfighter” accidents was many times less.
As carriers of nuclear bombs, F-104s were replaced at the end of the Cold War partly by Tornadoes (in Britain, Germany and Italy), and mainly by F-16s, which were purchased by many NATO countries. F-16 was certified as nuclear weapon delivery system in October 1980, and from then on it began to enter service in countries involved in Nuclear sharing, such as Belgium and the Netherlands, later joined by Turkey. Interestingly, although Greece also acquired the F-16 at a later date, it was never seen as a carrier; the Greek Air Force took on this role with the rather rare A-7E Corsair II attack aircraft.
The crucial issue of the early to mid-1980s in Europe was the so-called “Euromissiles Crisis”, associated with the deployment of Soviet SS-20 “Pioneer” systems first, and the American “Gryphon” GLCM and “Pershing 2” IRBM in response. All these weapon systems were nuclear and were operated respectively by the US Air Force and the US Army, without being transferred to the allies, and are not directly related to the topic of Nuclear sharing. However, they affected it indirectly — to limit the level of escalation, in parallel, the Alliance announced the start of withdrawal of various American 1,400 tactical nuclear weapons from the continent, some of those clearly involved in the nuclear sharing. The withdrawal of at least 1,000 of those had already been carried out in 1980.
After the INF Treaty was signed, the intermediate-range missile warheads disappeared, further decreasing the number of US nuclear weapons in Europe. Another connection of the Euromissiles Crisis with Nuclear sharing was that some of today’s B61 bomb shelters were originally built to store, among other things, W80 warheads for GLCMs.
In May 1990, the number of US nukes in Europe was around 4,000, of which around 1,400 were gravity bombs. On September 27, 1991, George H. W. Bush announced what would later become known as the Presidential Nuclear Initiative (PNI) — plans to reduce the deployment of American nuclear weapons abroad and eliminate many types of nuclear weapons. The first of these was the overseas deployment of tactical nuclear weapons — 1,000 nuclear artillery shells and 700 Lance surface-to-surface missile warheads were withdrawn from Europe. The first PNI did not include tactical air weapons, but after October 17–18, 1991, meeting NATO Nuclear Planning Group (NPG) announced that by supporting the PNI NATO would cut the number of gravity bombs in half, from 1,400 to 700.
However, due to the collapse of the USSR and the end of the previous Cold War, the reduction was even greater — by 1994 the number of US bombs in Europe had dropped to about 480 and remained at that level for a decade until, under the Bush Jr. administration, nuclear bombs were withdrawn from two major storage sites — Lakenheath in Britain and Ramstein in Germany. The bombs at these bases were intended primarily for use by US Air Force aircraft deployed there. After that, the only airbase in Europe (and for US Air Force tactical aviation in general) at which US aircraft are permanently deployed with US bombs is the Italian Aviano. So, these are more about forward deployment of US tactical nuclear weapons than NATO Nuclear sharing, but these topics are naturally closely related.
Besides, a little earlier, in the spring of 2001, the nuclear bombs were withdrawn from Greece, from the Araxos airbase, but it is not clear whether they were taken directly to the central storage facility in the US or moved somewhere else in Europe (e.g. to Ramstein and subsequently withdrawn to the US). In any case there were around 20 of them, which did not change the overall picture much. Naturally, in the 1990–2005, the number of airbases in the host countries where the bombs had been deployed and the number of units trained to use them were also reduced, but apart from Greece and the UK, the bombs were not withdrawn completely. It is only worth mentioning that probably for a long time (and even more so given the current US and NATO relations with Turkey) there has been no training in the use of bombs by Turkish pilots. The bombs are probably still stored at Incirlik Air Base, despite numerous reports, but are considered primarily as a forward base for the US Air Force in the Middle East.
Current status
Since the last major withdrawal of nuclear weapons by the Bush Jr. administration in the mid-to-late 2000s, the pattern of deployment in Europe has not changed in terms of geography, carriers used, types of bombs and units involved. However, this will change in the future.
Regarding the number of gravity bombs, the main source for all the last twenty years is Hans M. Kristensen (and friends) and the Bulletin of the Atomic Scientists. Their estimates are both widely circulated and quoted, and difficult to verify. Occasionally headlines like “NATO/Country-N has admitted that there are so many US bombs in Country-N” appear, but when checked it turns out that the report cited open data (i.e. Kristensen).
Current estimates are that the number of gravity bombs was reduced to 150–200 in the late 2000s and remained at that level until the early 2020s, when it was reduced to around 100. The geography of deployment did not change and the bombs were withdrawn roughly evenly.
Munitions in use
Since the early 1990s, the only NATO nuclear weapons have been thermonuclear bombs of the B61 family (currently B61–3 and B61–4), with variable dial-a-yields of 0.3–170 and 0.3–50 kilotons respectively. Tactical B61–10 “tactical” modifications were withdrawn from service in 2016. In addition to the tactical B61, the strategic B61–7 and B61–11 are also in service, which can now only be used by the B-2A Spirit heavy bomber. In practical terms, they have more powerful warheads, and B61–11 “penetrator” has reinforced body, lacks a parachute and can be used only from high altitudes. The other bombs of the B61 family are designed for use at a wide range of altitudes, including very low altitudes (up to “as low as 15 metres”) and flight speeds including supersonic. The possibility of safe use from low altitudes is provided by high efficiency kevlar parachute and possibility of detonation not only in the air or on the ground upon impact but also “landed” bombs on timer.
Mass — less than 380 kg (possibly around 320–350 kg)
Length — 3.6 m (142 in)
Casing diameter — 34 cm (13.4 in)
There are training versions, including those intended for practical bombing by NATO pilots at training ranges, such as BDU-36, BDU-38, BDU-39 (possibly also BDU-46). The BDU-38 is the most widely used.
Safety systems include command disable, weak link/strong link driven by unique signal generator. Security level CAT F PAL. Upgraded at least in second half of 1990s and early 2000s with introduction of Code Management System (CMS) (ALT 339). The codes are used in conjunction with Permissive Action Links (PALs) inside the nuclear weapon to recode, unlock, lock, and manage the weapons, while ensuring the secrecy and authenticity of launch orders. In total, the CMS consists of fourteen custom products (nine software and five hardware products).
B61–3/4 bombs have been produced in series since 1981, and the older 0/1 variants were also developed to this level.
Carriers
The primary carrier of B61-family tactical bombs in the USAAF is the F-15E “Strike Eagle” multirole fighter, which is the most powerful strike platform for US tactical aviation. It can carry up to five B61s, but it is difficult to imagine a mission requiring it — the typical load for tactical aviation during the previous Cold War was always one or two bombs. Given the small mass, the number of bombs suspended is limited not by weight per se but by the specifications of the hardpoints (not each of those were made “nuclear-capable”) and the capabilities of the weapons control system.
Judging by the test photos, the F-16s are capable of carrying up to two B61 bombs. The F-16s are B61 carriers in the participating European countries (Belgium, Holland, possibly Turkey), but it is unclear whether they are considered in this role in the US Air Force as a whole — not counting, obviously, two squadrons of 31st Fighter Wing deployed at Aviano along with bombs. It is reasonable to assume that most US Air Force F-16 squadrons have either no or minimal training in the use of nuclear weapons.
In Germany and Italy, the B61 carriers are European Tornado strike aircraft, which are retained in service in small numbers primarily for this mission. The Tornado is probably capable of carrying up to two B61s on the underbody (at least the British Tornado is assumed to have been able to carry up to two WE. 177), but the payload is probably one bomb, just like the F-16.
Future bombs and carriers
All existing bombs of the B61 family (except perhaps a small number of penetrating B61–11s) are planned to be converted into the new B61–12.
Officially it is only Life Extension Program (LEP), which aims primarily to increase the operational safety and “no overall change in military characteristics”. In particular, it stresses that not only the existing, but also the lightest of all devices from the B61–4 bomb (from 0.3 to 50 kilotons) is used.
However, this is in fact the most radical modification of the bomb during its development, as it is supposed to become guided by equipping it with a new tail kit, based on the JDAM kits. Unlike the JDAM’s inertial guidance system, the bomb receives pre-programmed target location data and updates from the aircraft prior to release.
This led to removal of the parachute, which probably precludes use from extremely low altitudes — so only air (from radar)/contact burst might be available. Test experience with the B61–11 showed the vulnerability of the B61 even with a reinforced design when penetrating hard ground so the possibility of a delayed detonation is questionable.
The main contractors for the production of the B61–12 are:
Sandia National Laboratories — design and engineering, electronics, including neutron generators
Los Alamos National Laboratory — design and engineering, electronics, including detonators
Kansas City National Security Campus — major non-nuclear components, including firing, safing, use control components
Y-12 National Security Complex — remanufacture warhead (primary uranium components)
Savannah River Site — testing, evaluating, and replenishing the tritium system
Pantex Plant — high explosives, requalifying the B61 pit, final assembly
Boeing Defense, Space & Security — tail kit
As a full-fledged guided weapon, the B61–12 can be used with the F-15E (certified) and potentially with the F-35A, B-2A, B-21. When used on F-16 and Tornado the tail kit will be locked and bomb used as legacy “ballistic”. Taking into account the absence of parachute and the limitation on altitude this mode of use is extremely inconvenient for older platforms, as they cannot use the extremely low altitude air defense penetration tactic.
The capabilities of the B61–12 are in tactical aviation are used to the fullest with stealthy F-35A. All NATO member states have already announced plans to buy it (Germany became the last one in 2022). Only Turkey’s acquisition of the F-35A has been blocked by the Trump administration due to sanctions; however, as mentioned above, the Turkish Air Force may have not actually participated in Nuclear sharing for a long time.
The B61–12 bombs have been tested on the F-35A, but nuclear certification on the serial fighters is expected from the Block 4 version, and probably not immediately. Even the US Air Force has not yet started supplying machines and upgrading the existing ones to this level. In the NATO Air Force this will definitely start after 2025 (deliveries of F-35A to the Luftwaffe even after 2026) and only then the combat capabilities of NATO nuclear forces will be increased.
Deliveries of the first B61–12 to the US Air Force have already started (or are about to start), deliveries of the first bombs to Europe were expected in spring 2023. As noted, they will be even less easy to use than the existing bombs at first, but they will allow ground and flight personnel to start training.
A total of 480 B61–12s are planned to be produced by 2026–27.
Bases and units
Find your neighbours!
Belgium — Kleine Brogel
701st MUNSS
10th Wing Tactical Belgian Air Component (31st&349th fighter squadrons; F-16)
Germany — Büchel
702nd MUNSS
Tactical Air Force Wing 33 Luftwaffe (Tornado)
Italy — Aviano
31st Fighter Wing USAF (510th &555th fighter squadrons; F-16)
Italy — Ghedi
704th MUNSS
6th Fighter Wing Italian Air Force (102nd& 154th squadrons; Tornado, 102nd in transition to F-35A)
Netherlands — Volkel
703rd MUNSS
312&313 squadrons Royal Netherlands Air Force (F-16, in transition to F-35A)
Türkiye — Incirlik
39th Air Base Wing USAF
Final words
STRATDELA has serious doubts that ‘tactical’ weapons have a feasible role on modern battlefield, nuclear escalation can’t be controlled. Limited numbers of US nuclear weapons currently deployed in Europe, as well as even more limited numbers that might be deployed to Belarus by Russia, are probably just a material proof of virtual “nuclear umbrella” more than anything else. Still, these capabilities are taken into account by military planners in all countries involved, and hardly contribute to greater stability. When and if a discussion of new security architecture for Europe starts, addressing non-strategic nuclear weapons must become an important part of that, especially the link of those with the conventional capabilities of everyone involved.
As for the NPT-related issues…well, it’s complicated:) It makes perfect sense to keep one’s nuclear weapons within one’s national territory, but security concerns forces decision-makers to think otherwise. So, to find a good solution we should address those concerns in the first place.
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