Feasibility Study of an Earth Melting Penetrator System for Geoprospecting Tunnel Right-of-Ways.

摘要

The Earth Melting Penetrator (EMP) is a concept utilizing high-temperature penetrator tips at the leading end of a length of nonrotating stem to melt earth materials in its path and leave an open hole for geologic exploration purposes. The early proof-of-concept testing was performed by the Los Alamos Scientific Laboratory. Westinghouse Corporation Advanced Energy Systems Division developed a conceptual design and cost estimate for a technically feasible EMP system (including heater, core handling, power transmission, and power generation subsystems) capable of penetrating a 3-mile long right-of-way path through rock and soil and recovering a 3-in. -diam core from that hole. The heater tip is an annular extended surface tungsten body heated to 2300 C by pyrographite resistance elements. A special annular configuration downhole electrical transformer was designed to convert 1.25 mw of electric power from high voltage-low current transmission mode to low voltage-high current heater mode. A special power generation and control system using paralleling and load sharing between three 680 Hz, 900 kw diesel-powered generators was designed. Tip-steering techniques were established. Several tip-location (guidance) schemes were examined, and it was found that an inertial system would be best but was outside the current state of the art and that a combination electrolitc level-compass scheme would be marginally adequate but technically feasible.