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Decontamination and Dismantling (D&D) of Explosive Contaminated
Process Piping in High Explosive Load Lines
Paul L. Miller; Gradient Technology; Elk River, MN, USA
Keywords: Decontamination; Dismantling; Explosive Contaminated; Piping; Abrasive Waterjet
Abstract
Large amounts of piping and related equipment contaminated with high explosives recently had to be removed from
several facilities as part of major facility refurbishments and upgrades. Some of these pipes, pumps, and process
vessels had been in service up to 75 years and were known to contain a variety of explosive materials. The majority
of the components were process vacuum line systems that were installed in order to capture and remove explosive
materials generated during the milling of projectile fuze pockets in pressed or cast explosives or the machining of
explosive billets. Two of the load-lines had vacuum piping that had been installed in the early 1940s. They were
known to be contaminated with various explosive materials from the Second World War through Vietnam. The third
production line was built in the 1960s and had process lines that were believed to contain pyrotechnic or toxic
chemicals of unknown composition and reactivity.
A preliminary hazards analysis of a number of decontamination and dismantling (D&D) processes provided a
probabilistic risk assessment to determine what could go wrong, how likely the failure was, and what would be the
likely consequences of the failure. This analysis allowed management and engineers to evaluate design and
operational risks, cost, and schedule impact while meeting all of the safety requirements. Among the various
processes evaluated were manual disassembly, bandsawing, rotary displacement cutting, diamond wire sawing,
rotary lathe cutting, abrasive waterjet cutting, and hydraulic shearing. Traditional disposal methods, such as burning
out the facility, were not acceptable on environmental grounds as the facilities contained asbestos paneling that
would have become a downwind airborne hazard. In addition, the facilities were slated to be reutilized, not
destroyed, and had to have minimal or no collateral damage. The location and clearance around the piping and
equipment had to be evaluated as some of the processes would not have sufficient access to safely section the
targeted items. Also, the post-cut processing of the contaminated piping had to be evaluated to prevent an initiation
of the contaminants while the piping and equipment was being removed.
Approximately 600 cuts were ultimately required to safely section the piping, and large amounts of explosive were
found in the piping validating the time and effort spent on the hazards analysis. The projects were all completed
without incident and with minimal impact on the facilities.
1 Introduction
Modernization of several explosive processing facilities recently required the decontamination and dismantling
(D&D) of contaminated process piping and related systems. Some of these pipes, pumps, and process vessels had
been in service up to 75 years and were known to be contaminated with a variety of explosive materials. The
majority of the components were process vacuum lines that were installed to remove finely divided explosive chips,
dusts, and shavings generated during the milling of fuze pockets in pressed or cast explosives. Two of the load-lines
had vacuum piping that had been installed in the early 1940s for operation during the Second World War. The units,
known as “vacuum accumulator collection systems,” were actively used for processing explosive munitions through
the end of the Vietnam era. The third production line was a research and development process line built in the 1960s
that was believed to contain pyrotechnic or toxic chemicals of unknown composition and reactivity. The operation
had been shut down, presumably in the 1970s, and still contained in-process materials.
Prior to dismantling these systems a thorough safety hazards analysis was performed to determine what cutting
technologies were applicable for the D&D of the explosive contaminated process piping and a corresponding risk
assessment.
