Nuclear weapons security for geeks

Good time!
Recently they argued whether the commander of a nuclear submarine is technically capable of autonomous use of strategic nuclear weapons. Those. with a complete loss of communication with the command, can he (albeit with the senior mate) unleash the third world war or not ?! The crazy terms “weapon of retaliation”, “fatal error”, etc. went to the course. Who and why won champagne in the end, if interested, I will tell in a separate story. There is something to write about.

And now I would like to share some interesting information that I discovered while I studied Google’s response to the keywords "nuclear unlock codes", "combat signals of the nuclear submarines" (by the way, I’m waiting for the right people to take an interest in my curiosity :)).

The information concerns technical measures to ensure the safety of the storage, transportation and use of nuclear ammunition. Since in the US the veil of secrecy falls off over time, they have something to read. RF, I believe, should be in wake.

What do the USA have now?
In the United States, ground-based ballistic missiles have traditionally received less attention than bomber or sea-based missiles. For 2000, the composition of the ground grouping of US strategic forces consisted of 500 Minuteman III and 50 MX missiles, with a total of 2,000 warheads .

The maritime component of the triad is considered the most significant component of the US strategic nuclear forces. The armament consists of 192 Trident I missiles and 216 Trident II missiles deployed on 18 submarines. The total number of warheads on these missiles is 3,456 .

Strategic aviation has for a long time been the basis of the US strategic arsenal. In 1959, the United States was armed with over 1,800 intercontinental bombers. And although after the appearance of ballistic missiles, the role of bomber aviation decreased significantly, the United States continued to pay considerable attention to aviation. As part of strategic aviation are 21 new bomber B-2 and 76 aircraft B-52. The number of warheads intended for delivery by aviation is approximately 1,750 units . About 150 tactical aerial bombs are located at 10 air bases in 7 NATO member countries. A significant part of tactical bombs can be placed on the planes of the US allies of NATO.

How do they ensure the safety of nuclear weapons?

The design features of modern nuclear ammunition are guaranteed by the following security measures: prevention of accidental explosion of ammunition in normal and emergency conditions, accompanied by release of nuclear energy or scatter of harmful radioactive products; exclusion of a nuclear weapon cocking or launch of a delivery vehicle in case of erroneous or malicious actions of the attendants; The prohibition of the normal functioning of a nuclear weapon when it is seized by an adversary, terrorists, or accidental individuals; automatic withdrawal of ammunition when attempting to penetrate the vital elements of its nuclear charge.

In the first models of nuclear weapons, including in the bombs dropped on Hiroshima and Nagasaki, security was achieved by storing them in disassembled form and final assembly just before combat use (aircraft discharge). Ammunition of this type was in service with the United States in the 40s and 60s.

At the end of the 1950s, nuclear weapons, stored assembled and ready for combat use, began to enter service. The required safety in such munitions is ensured due to their equipment with an explosion system with multiple locks, whose operation is based on different principles, which minimizes the possibility of an accidental nuclear explosion.

The probability of an accidental operation of the ammunition automation units is very small, and their emergency activation is impossible, since they operate on different principles, the simultaneous use of which is excluded for any accident.

In the 1960s, the US State Commission and the group of experts who were checking the state of these weapons at that time concluded that their safety was ensured only by the strict protection of storage facilities, and the detonation system used in ammunition practically did not create any obstacles to its immediate use after capture by terrorists.

To eliminate this shortcoming, in 1963–1966, the United States upgraded its tactical nuclear munitions located in Europe, during which they installed special electromechanical or electronic PAL (Permissive Action Link) safety devices.

PAL create an additional blocking in the chains of detonation of the munition, which is removed at the direction of the high command when preparing weapons for combat use or with the start of hostilities. To unlock, use a digital code dialed by the service personnel or the crew of the aircraft.

This allowed the United States to attract for the duty of combat duty (on the ground - with hanging nuclear weapons) aircraft carriers of other NATO countries and in fact retain control of these weapons. PALs ensured that American nuclear weapons would not be used without the approval of US senior management.

In the early 1970s, American experts concluded that the design of ammunition should provide reliable protection in the event of a possible seizure of nuclear weapons, that is, they must have built-in personal protective equipment that prevents any kind of invasion of their automation.

To this end, by the mid-1970s, electronic automatics for the detonation of nuclear weapons, based on the concept of “weak and strong links”, were created in the USA. Its essence lies in the separation of critical elements of automatic blasting into weak and durable from the point of view of their potential destruction in emergency situations, as well as unauthorized physical or electronic access to the inside of the munition. To ensure the same impact of adverse external factors on these links, they are located together with a nuclear charge in a specially equipped area of ​​the munition.

The elements that make up strong and weak links are structurally designed so that in case of fire, shock loads and other influences, as well as intrusion into the ammunition, weak links would fail (completely and irreversibly) much earlier than strong ones. Due to this, in any accident, the managers and some executive bodies of the explosion (weak links) are completely disconnected from the nuclear charge until the final destruction of the automation.

Thus, weak and strong links, besides providing security in emergency situations and prohibiting access to the ammunition, exclude the possibility of using nuclear weapons in combat without the approval of the High Command, which in previous releases tactical munitions were carried out by more simple special PAL safety devices.

Plutonium safety
... these are measures to reduce the likelihood or complete elimination of contamination of the area by plutonium during fires and other accidents.

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January 17, 1966 over the Atlantic Ocean to the area of ​​Palamares (Spain), when a B-52 bomber with four nuclear bombs with a capacity of more than 1 Mt each, carrying combat duty in the air, collided with the KS-135 tanker aircraft, damage and caught fire. The crew of the B-52 before the ejection accidently dropped all nuclear bombs (without the cocking). Two of them, falling on solid ground in the area of ​​the settlement, collapsed and caused a significant radioactive contamination of the area. During decontamination, it was necessary to export 1,400 tons of soil and vegetation in airtight containers to the United States for further processing.

The second major crash of a B-52 strategic bomber with four bombs of 1.1 Mt occurred on January 21, 1969 in the area of ​​the city of Tula (Greenland). The plane, which participated in the teaching of strategic nuclear forces, caught fire and fell along with the bombs on the ice, not having reached 10 km from the runway of the airfield. All nuclear bombs were in the fire zone, which caused their depressurization and plutonium dispersion over a fairly large area. Plutonium-infected ice and water were transported to the United States.

After a wide political resonance in the wake of the accident, in the first half of the 80s, the United States began to receive aircraft nuclear weapons, where the so-called insensitive blasting explosives are used instead of conventional brisant ones. Charges stuffed with them do not explode in case of intense fire and powerful loads during an impact (for example, when an airplane falls), which significantly reduces the danger of the area being contaminated with plutonium.

Currently, by congressional decision:
- in the US nuclear arsenal, there should be only ammunition, whose automation is based on the concept of “weak and strong links” (ammunition that does not satisfy this concept is planned to either be removed from service or modernized);
- All aircraft ammunition (bombs, missile warheads) must be equipped with insensitive explosives and fire-resistant shells;
- in developing tactical and technical requirements for new types of nuclear weapons, safety issues should have the highest priority, and the necessary safety criteria should be provided even to the detriment of power and their other characteristics.

Information sources:
- Ensuring the safety of nuclear weapons in the US / B. Kovalenko /
- Nuclear encyclopedia. Nuclear weapons / P. Feat/
- Nuclear disarmament, nonproliferation and national security / I.A. Andryushin, V.P.Varava, N.P. Voloshin, V.S. Zakharov, S.A. Zelentsov, R.I. Ilkaev, V.M. Loborev , V.N.Mikhailov, A.K. Chernyshev, Yu.A.Yudin. /