Trident Safety

Facts compiled by members of Disarm Now Plowshares

By today's military and scientific standards, Trident II D-5 is inherently unsafe. However, the things that make D-5 unsafe today were considered acceptable in the 1970's. Because the Trident Weapons System was developed as a Cold War imperative, the level of risk to the public as a result of deploying the system was considered small compared to the risk of nuclear annihilation if the US government failed to deploy the system.  Since the Cold War has been over for nearly 20 years, and the level of risk tolerance by the general public in all facets of daily life has reduced substantially during the same period, Trident now poses an unacceptable risk that is no longer justified by the threat of use of nuclear weapons against the US. (p. 262, John R. Harvey and Stefan Michalowski: Nuclear Weapon Safety: The Case of Trident.)

There are several safety concerns inherent in the Trident Weapons System:
 1.   The W88 warhead in the Trident Reentry Vehicle (RV) employs Conventional High Explosive (HE) to initiate nuclear detonation.  This is necessary in order to meet size and weight requirements for the RV's to fit in the annular space around the third stage rocket motor and still meet range requirements.  Conventional HE, however, is much more susceptible to detonation in impact and fire accidents. For this reason, in 1983 the DOD instituted a requirement that Insensitive High Explosive (IHE) be used in new warheads unless an important military need warranted otherwise. Such a waiver was granted for the W88 because the DOE weapons labs could not meet DOD RV size, yield, and weight requirements with an IHE warhead.
2.    In order to achieve maximum range requirements, all three stages of the D-5 missile use "high energy" (Class 1.1) propellant.  Class 1.1 propellant is much more likely to detonate in impact accidents than the less-energetic Class 1.3 material used in many ICBMs.

 3.   The safety concerns above are exacerbated by the unique through-deck design of Trident D-5.  In order for the missile to meet range and throw weight requirements, and fit in a submarine launch tube, the third stage rocket motor penetrates the lower deck of the of the post-boost vehicle (PBV) (the "bus" that houses the warheads).  This is in contrast to land based ICBM's which are not length constrained.  ICBM's employ a clear deck design where the PBV sits on top of, and is physically isolated from the third stage rocket motor.  The through-deck configuration is more sensitive than clear-deck designs to impact and fire accidents, which could endanger not only military personnel on the base but also the public at large via the release of plutonium and its transport by prevailing winds to populated areas.
In analyzing possible accidents, Harvey and Michalowski write, "a dropped missile or an airplane crash (accidental or deliberate) inside the limited area could create impact pressures and temperatures sufficient to cause motor detonation or fire.  There is also the possibility of sabotage; for example, boosters or RVs could come under heavy weapons fire from a terrorist group during transport to the loading wharf." (page 279)

We, the plowshares activists, conclude that the risk of plutonium dispersal to military at the base and to the wider community is too big a risk to take. The Trident program should be scrapped, one of the options considered in Harvey and Michalowski’s risk analysis, unless 150 billion dollars are spent in redesign. (page 337)