Device systems lightning project: Final report

This report documents a project that implemented a key recommendation of the Nuclear Explosive Lightning Vulnerability Investigation Task Force. A prototype, lightning invulnerable, nuclear explosive test device system (LIDS) was designed, fabricated, and tested. Severe threat-level simulated lightning and rocket-triggered natural lightning were discharged into both coaxial and multiconductor cables. These cables were connected to standard arming and firing (A and F) components located within the LIDS. Cables and circuits typically associated with device systems ancillary ac power were not tested. Subsequently, a detailed data analysis was carried out by the Science and Engineering Associates, Seattle, Washington, under subcontract number 9749605. This analysis confirmed the observations of the experimenters, namely that the prototype LIDS protected the safety-critical components from severe threat-level lightning transient energy. Simulated electro-explosive devices (EEDs) connected to the A and F components did not ''fire'' under any of the test conditions. However, current measurements for the EEDs were inconclusive, making it impossible to evaluate a safety margin for electromagnetic coupling into those circuits. Nonetheless, estimated upper bounds of peak currents and action integrals, extrapolated to severe threat levels, are significantly below the values required to fire the most sensitive EED (i.e., SE-1 detonator: required action integral =more » 0.1 A/sup 2/-sec; ''no-fire'' current = 74 A). Although the testing was intended to demonstrate protection against a severe lightning strike, the analysis pointed out that a relatively low-level, long-duration strike could conceivably produce partial charging of A and F components. Evaluation of this phenomenon as a potential threat was beyond the scope of this report, but it should be looked into.« less