CARLSBAD, N.M. - Aloha!
A little bit of the tropics has planted itself firmly at EM’s Waste Isolation Pilot Plant.
Palm trees sway gently in the breeze…well, OK, they’re not really palm trees. They just look like them, and they’re essential to protecting vital parts of the WIPP facility.
The metal “palms," known as hemisphere arrays, are part of the WIPP lightning protection system. They are high in the air at five locations: Two at the exhaust filter building, one at the salt shaft, one at the air intake shaft, and another at the water tanks used to fight fires.
The distinctive structures generate more questions than any other on WIPP tours.
The system is needed because of the immense power carried in a lightning bolt. As a comparison, an average home’s electrical system is 120 volts and 100 amps. A negatively charged lightning bolt from a New Mexico summer storm can contain 1 billion volts and up to 200,000 amps. A direct strike can cause fires and severely damage electrical circuits.
The system protecting WIPP turns the technology of Ben Franklin’s kite-and-key days on its head. Instead of putting a metal lightning rod high in the air to channel the inevitable strike and then dissipate it into the ground, the goal of the system at WIPP is to eliminate lightning strikes altogether.
In Franklin’s day, the objective was to keep lightning from burning down a wood building. Today’s buildings, packed with sensitive electronic devices such as computers, could suffer great harm if the lightning was merely nearby.
There have been no strikes on WIPP buildings since the structures were installed in 1987. That’s 31 years in an area awash in summer thunderstorms, and after the upcoming season, the aging system will be retired and replaced with a new one in 2019.
“We have had a few close calls, but no confirmation of a direct strike. The system appears to be working exactly as intended," said Hector Jimenez, an electrical and system engineer for Nuclear Waste Partnership, WIPP’s management and operations contractor.
In the event of a strike, the charge would still be routed to the site grounding grid, an in-ground copper grid beneath the entire facility.
Made by Lightning Eliminators & Consultants of Boulder, Colo., the Dissipation Array System is loosely based on a patent filed in 1913 by inventor Nikola Tesla. Tesla’s patent paperwork even shows something resembling palm fronds.
Lightning occurs when negative electrical charges (electrons) at the bottom of a cloud are attracted to positive charges (protons) on the ground and on buildings. As the earth attempts to balance the electrical field and the two forces pull on each other, “streamers" coming up from the ground and “step leaders" coming down from the cloud connect, creating a path for a lightning bolt.
The WIPP array disrupts the upward stream through a phenomenon known as “point discharge," where the multiple points on the “palms" use the earth’s increased positive particles during a storm to create a charged ion cloud over WIPP and prevent the streamers.
Source: U.S. Dept. of Energy, Office of Environmental Management
