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About Sigma-NAC Nuclear Solutions, LLC

Small business resources providing exceptional nuclear professional services combined with state-of-the art radioactive material and fuel storage and transport technologies and systems.

Sigma-NAC Nuclear Solutions, LLC (SNNS) combines the strength of two trusted providers in the nuclear industry—Sigma Science, Inc. and NAC International Inc. Together, we provide an integrated suite of solutions in waste analysis; problematic waste streams; advanced reactor fuels; and packaging, logistics, transport, and disposal for spent nuclear fuel (SNF) and radioactive waste.

For over 25 years, Sigma Science has been providing nuclear professional expertise and technical solutions for some of the most difficult nuclear materials and waste challenges for both federal and commercial clients. Sigma has a proven track record of providing nuclear engineering; nuclear facility and transportation safety basis analysis; radiological shielding and criticality analysis and characterization; problematic high hazard nuclear waste and fuels analysis, treatment, characterization, packaging, and transportation; nuclear safeguards and security; and environmental compliance.

For more than 50 years, NAC has been a leading provider of nuclear fuel cycle technology and consulting solutions. Founded in 1968 as Nuclear Assurance Corporation, NAC was recognized early on for its pioneering nuclear market information services and later established a highly successful SNF storage and transport cask design and licensing business worldwide. NAC now is a global provider of fuel cycle consulting services and patented, unique technology solutions, including engineering, licensing, and supplying casks and canister solutions for spent fuel and high-level waste.

Brochure and Latest News

Sigma-NAC Nuclear Solutions, LLC

Areas of Expertise

SNNS offers the following services and expertise

  • High hazard nuclear waste analysis, characterization, and treatment
  • Problematic waste stream analysis and solutions
  • High-level/greater-than-Class-C/transuranic/mixed low level waste packaging, transportation, and storage
  • SNF technologies including casks, containers, and storage systems
  • Waste disposal brokerage and contract management

SNNS supports federal and commercial clients including:

  • National Nuclear Security Administration
  • DOE Office of Environmental Management
  • DOE Office of Nuclear Energy
  • DOE Office of Science
  • Department of Defense
  • Army Corps of Engineers
  • Commercial Nuclear Utilities including Arizona Public Service, Duke Power, Constellation, and others
Sigma-NAC Nuclear Solutions, LLC


SNNS combines the past performance of both Sigma and NAC, including:

  • Design and construction of the High-Level Waste Dry Storage System at West Valley
  • Nuclear fuel development, SNF processing, nuclear facility operations, nuclear engineering analysis, safety basis analysis, and evaluation of alternative uses of nuclear fuels at Oak Ridge National Laboratory
  • Independent assessments, criticality safety evaluations, and packaging/transportation analysis for the NAC HALEU Project
  • Criticality safety engineering and reviews of waste/SNF package fissile material contents
  • Completing over 3,700 shipments of SNF and nuclear waste worldwide in support of DOE and other government and commercial programs

North American Industry Classification System (NAICS) Codes

Primary NAICS Code

562910 – Remediation Services

Secondary NAICS Codes

541715 – Research and Development in the Physical, Engineering, and Life Sciences (except Biotechnology)
561210 – Facilities Support Services
541330 – Engineering Services
562112 – Hazardous Waste Collections
562119 – Other Waste Collection
562211 – Hazardous Waste Treatment and Disposal