There was a download of RESRAD-ONSITE 7.2.7.3 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. RESRAD-ONSITE is included in Education Tools. The most popular version of the program is 7.2.
Commonly, this program's installer has the following filename: Reswin6.exe. This free program is an intellectual property of Argonne National Laboratory. This PC program works fine with 32-bit versions of Windows 7/10/11. We cannot guarantee that the program is safe to download as it will be downloaded from the developer's website. Before launching the program, check it with any free antivirus software.
From the developer:
RESRAD-ONSITE (formerly just RESRAD) is a computer code designed at Argonne National Laboratory for estimating radiation doses and cancer risks to an individual located on top of radioactively contaminated soils and to derive radionuclide soil guideline levels corresponding to a specific dose criterion.
You may want to check out more software, such as gitoolbox, MemBrain or roboBASIC, which might be similar to RESRAD-ONSITE.