RELAP5-3D 4.x: Thermal-Hydraulic Nuclear Reactor Analysis, Licensing Opportunity
Special Notice from Department of Energy.
Data as of Oct 24, 2026. Sources: SAM.gov and Grants.gov. Snapshot govcon-directory-20261024T104923Z-2151694.
This product uses the Grants.gov API but is not endorsed or certified by the U.S. Department of Health and Human Services. Counts and totals are computed by DSE from public SAM.gov and Grants.gov notices. Text from Grants.gov may be shortened or have contact details removed. The original notice on Grants.gov is the authoritative version.
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Notice details
- Agency
- Department of Energy
- Sub-tier agency
- ENERGY, DEPARTMENT OF
- Notice type
- Special Notice
- Solicitation number
- CW-25-06
- Product/service code
- R412
- Place of performance
- Idaho Falls, Idaho
- Posted
- Apr 21, 2026
- Response deadline
- Nov 1, 2026
- Source
- SAM.gov
Description
Technology Summary: RELAP5-3D is a fully integrated system-level modeling code for simulating the behavior of nuclear power plants and other complex thermal-fluid systems. Originally developed for light water reactor safety analysis, RELAP5-3D supports detailed modeling of multiphase flow, heat transfer, reactor kinetics, and fluid-structure interactions. It is capable of performing both steady-state and transient analyses in one-, two-, or three-dimensional geometries, making it one of the most versatile nuclear systems analysis tools in use today. Problem Addressed: Designers, operators, and regulators of nuclear systems need validated tools to simulate a wide range of operating and accident scenarios, from routine transients to complex multi-physics events. Many commercial codes lack the physics detail or numerical flexibility needed to capture the behavior of advanced reactor designs, high-fidelity safety cases, or coupled systems involving multiple working fluids or complex geometries. Proposed Solution: RELAP5-3D enables high-fidelity simulations of nuclear thermal-hydraulics and safety behavior. Key capabilities include: Modeling of single- and two-phase flow using a two-fluid model Support for multiple fluids, flow regimes, and non-condensable gases Built-in reactor kinetics and neutron transport models (point kinetics or 3D neutron kinetics) Fully coupled heat structures and control system modeling Parallel processing and restart capabilities for large, complex runs
Summarized from the official notice. The description is shortened; read the full text on the official notice.
Official notice
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When is the response deadline?
The published deadline is Nov 1, 2026. That is 8 days after the data date.
What NAICS code applies?
NAICS 541690, Other Scientific and Technical Consulting Services.
Which agency issued this notice?
Department of Energy.
Where is the official notice?
The link under Official notice opens the source listing.