Divine Strake Operating Plan
The proposed operating plan includes acceptable blast conditions, the procedures for filling the charge hole with ANFO (batch and emplacement plan), detonation, and monitoring.
Prior to the detonation, the extended meteorological forecast for 7 to 14 days would be evaluated. If meteorological conditions were not satisfactory, the emplacement of the ANFO emulsion and the detonation would be postponed. Required meteorological conditions would be no temperature inversions, no more than 40 percent stratus or cumulus cloud cover, and winds less than 25 miles per hour blowing from the southwest (240 degrees) through southeast (120 degrees). Winds blowing to the northeast to northwest would help direct the blast pressure forward onto the northern half of the NTS, away from most NTS facilities and the offsite communities south of the NTS.
The analysis in the Environmental Assessment assumed the following acceptable blast conditions:
- Surface Winds: Southerly (from 120° through 240°) up to 25 miles per hour
- Winds Aloft: Southerly (from 120° through 240°) up to 50 miles per hour
- Lapse Rate: 3° Celsius per kilometer (moist adiabatic to unstable)
- Temperature Inversions: No temperature inversions from surface to tropopause
- Cloud Cover: No significant low to mid level cloud cover (less than 40 percent)
- Thunderstorms: No thunderstorms or lightning within a 20 mile (32 kilometer)
Meteorological conditions would be carefully monitored and evaluated by competent personnel assigned to the NTS prior to NNSA approval for the detonation. If appropriate meteorological conditions do not exist, the detonation would be delayed until the required conditions are met. Other acceptable blast criteria would include technical criteria such as equipment/sensor failures and power failure to the instrument van.
To batch (or mix) the ANFO, materials for batching would be brought in as needed, transferred to one of the four bulk delivery trucks, and transported to the pad adjacent to the charge hole. The trucks would mix the raw ingredients into a blasting agent (ANFO) and discharge directly into the hole via an auger. The 700 tons (635 metric tons) of ANFO would be batched into a semi liquid emulsion (Dyno Gold Extra, formerly know as Dyno Gold C / (a registered trademark of Alpha Explosives)) consisting of 78.65 percent ammonium nitrate, 5.52 percent calcium nitrate, 9.45 percent water and 6.38 percent fuel oil. The batching process would take approximately 4 to 5 days to provide the 700 tons (635 metric tons) of ANFO. A small pipe or tube would be placed in the center of the hole prior to filling with the blasting agent. This pipe would allow the booster and detonators to be installed just before DIVINE STRAKE is detonated. Spill tarps would be placed under the fuel truck, the raw material tankers, and the parked bulk delivery trucks. Clean up and housekeeping activities would be constant. Upon completion of loading the charge hole, the trucks, storage trailers, and any remaining materials would be removed from the site.
DIVINE STRAKE would be detonated using a remote firing system. A signal would be generated at the remote data acquisition facility and transmitted through a microwave link to U16b where it would be fed into the arming and firing unit in the small pipe installed in the charge hole prior to loading the ANFO emulsion into the hole. Exploding bridgewire (EBW) detonators would be used to detonate the explosives. There will be a dual system of EBWs (one primary and one backup). A high voltage pulse would be sent to the EBWs, which would be embedded within 100 to 300 pounds (45 to 136 kilograms) of C 4 (booster) located in the center of the ANFO charge. The EBWs and the C 4 would not be added until after the ANFO has been emplaced in the charge hole, acceptable blast criteria have been satisfied, and a final dry run has been completed. Additionally, there would be a second backup firing system using a detcord line running down the length of the small pipe and into the booster. The detcord would also be initiated with another EBW.
To detonate DIVINE STRAKE, EBWs would fire, detonating the C 4 and in turn detonating the ANFO mixture. If the first two EBWs were nonfunctional, the detcord would be fired and the "burn" would propagate down to the booster and then initiate the blasting agent. Detonation products would include water, nitrogen, carbon dioxide, methane, and calcium carbonate.
Both microbaragraphs and three axis seismometers will be deployed at up to 36 stations both on and off the NTS to measure the airblast overpressure time records and seismic ground shock resulting from the proposed detonations. These types of measurements have been routinely performed on other large explosive detonations to ensure public safety, but also to improve the predictive capability for the long range effects. In addition, visual and photographic surveys will be conducted pre and post detonation to evaluate the effects of the ejecta, airblast, and dust on both biota and facilities.
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