Amid reports of yet another increase in the estimated cost of the Superconducting Super Collider (SSC) -- to perhaps $11.7 billion -- the Department of Energy has postponed today's scheduled delivery to Congress of its official projection of the controversial project's price tag.

The total cost of the huge particle accelerator, which is designed to study the origin and fundamental nature of matter, was originally estimated at $4.4 billion in 1987. Recent estimates have ranged from $7.8 billion to $8.9 billion.

Now a DOE internal accounting group, one of four panels the department asked to estimate the costs, has reckoned the total price to be as much as $11.7 billion, according to the Aug. 6 issue of the industry newsweekly Inside Energy.

Energy officials decline to confirm or deny that estimate. A spokesman for the agency said DOE's official figure, reconciling the disparate estimates, would not be presented to Congress until Sept. 7. Deputy Energy Secretary W. Henson Moore had told reporters early this month that the DOE figure would be delivered today.

Word of the latest estimate "certainly will strengthen opposition to the project," said an aide to the Senate Energy and Natural Resources Committee. "On the other hand, this has become a public works project. So, looking at it that way, the fact that it costs more may not be considered all bad."

The estimate said to project the SSC's cost at between $11.5 billion and $11.7 billion was prepared by DOE's Independent Cost Estimating group (ICE), which attributed the increase to its anticipation of schedule slippages or unforeseen technical problems, as well as an increased amount required for the collider's giant detectors, which record the results of particle collisions.

A spokesman for a prominent scientific group who asked not to be identified said the official DOE figure likely would be toward the lower end of the range. He criticized the pattern of underestimating the costs of big science projects in order to get them approved, which he said has become chronic.

"If you really hold them to the low figure, the chances of having another Hubble go way up," he said, referring to the $1.6 billion Hubble Space Telescope, whose focus has been temporarily ruined by a built-in mirror flaw. "People start cutting corners and taking risks."

The SSC, which would surround Waxahachie, Tex., with a 54-mile tunnel, would be the world's most powerful particle accelerator and possibly the nation's largest and most costly single scientific device. Current plans call for it to be completed in 1998.

In a search for clues to the forces that created the universe, scientists would study the exotic debris produced when the strong field hurls streams of protons around the tunnel to collide against each other at almost the speed of light.

Advocates of the project say it could unlock the key to physical reality, by recreating the fundamental particles and forces that existed in the first few quadrillionths of a second after the universe exploded into existence in the theoretical cataclysm known as the Big Bang.

Opponents say it is one of several proposed "Big Science" projects that will drain resources from small projects that are less risky and more practical.

Opponents also say there is a chance that a much less costly accelerator being built by a European consortium for completion before the SSC may beat the SSC to its chief quarry, discovery of a key subatomic particle postulated in theory.

The Senate recently approved a spending bill containing $318 million in 1991 for the giant atom smasher. U.S. officials, declaring the project "too big for one country," have sought added funding from Japan and other countries.