Tetra Tech Inc. said Tuesday it acquired Haselwood Enterprises Inc., a nuclear science and engineering company in Tennessee, for an undisclosed amount.

The Pasadena-based engineering and consulting firm said HEI has annual revenue of approximately $14 million and will enhance its capabilities and service offerings to the National Nuclear Security Administration, the commercial nuclear industry and the U.S. Department of Energy.

HEI, which has about 120 employees and headquarters in Oak Ridge, provides program management and technical services for nuclear materials management, nuclear weapons operations and infrastructure, environmental remediation, and waste management. The new Tetra Tech division will be led by Greg Rudy, who formerly managed the Savannah River Site in Aiken, S.C. for the Energy Department.

Tetra Tech shares were up 71 cents, or 3 percent, to $24.36 in morning trading on the Nasdaq.