Thunderous booms and fireballs near key electrical substations in Vicksburg next week will signal the first use of implosive technology in Entergy’s four-state area, but the tests might frighten unsuspecting people and pets.

Starting Tuesday morning, crews will fuse together parts of a key electrical transmission line between Vicksburg and Clinton using an IMPLO connector, a device common in line construction that uses dramatic, low-risk implosions to seal unconnected segments of wiring. The first of about 20 booming implosions slated through mid-January will occur at the Vicksburg switching station near Mississippi 27 and Old Highway 27. Six more implosions will repair parts of the line at the Waterways substation at Wisconsin Avenue and Bazinsky Road.

The line provides power to about 12,000 Entergy customers served by substations in Vicksburg, Edwards, Bolton and Clinton. Corrosion over time prompted the repair to “beef up that line,” said Don Arnold, Vicksburg area spokesman for Entergy Mississippi.

“That sound you hear is not the return of the Union army,” Arnold said. “It’s actually a project that’s designed to improve service reliability to our customers.”

Developed in the 1960s in Europe, the method involves an implosive material that is wrapped around an aluminum sleeve to create energy needed for compression. A charge is set off by a non-electric detonator safe enough to use on energized lines. The detonation lasts one-ten thousandth of a second and creates a 110-decibel sonic boom — about the same as a 12-gauge shotgun blast. Segments are spliced in a fraction of the time compared to a traditional hydraulic compressor, according to Entergy.

Implosive technology, a favored method in recent years among power companies for line repairs, produces a stronger sleeve that won’t bend or corrode as easily and is geared to withstand limbs better than before, said IMPLO project manager Gary Di Troia.

Equipment will be set up Monday at each site by Entergy crews and project managers with Canada-based Burndy LLC, parent company of the device’s development firm, as an initial implosive splice will take place about 2 feet off the ground, Entergy’s Shannon Watts said.

Entergy says Tuesday’s sights and sounds are part of $90 million spent this year on distribution and transmission reliability projects.

In March, the East Vicksburg substation on Porters Chapel Road was fitted with an animal-proof fence designed to keep raccoons, squirrels and other critters from causing power outages. Twice in 2009, outages at that station and one on Iowa Boulevard were blamed on small animals.

Entergy Corporation provides power to 2.7 million customers in Mississippi, Louisiana, Arkansas and Texas. The Mississippi subsidiary provides power to 435,000 customers in 45 counties.