Lawrence Livermore National Laboratory



The HotSpot Health Physics codes were created to provide emergency response personnel and emergency planners with a fast, field-portable set of software tools for evaluating incidents involving radioactive material. The software is also used for safety analyses of facilities handling nuclear material.

The HotSpot atmospheric dispersion models are designed for near-surface releases, short-range (less than 10 km) dispersion, and short-term (less than 24 hours) release durations in unobstructed terrain and simple meteorological conditions. These models provide a fast and usually conservative means for estimation of the radiation effects associated with the atmospheric release of radioactive materials.

The HotSpot codes have been developed for the Windows operating system(s). To register and download the HotSpot software, click here. You do not need to have a NARAC or CMweb account to access HotSpot.

The HotSpot Radionuclide Library incorporates Federal Guidance Reports 11, 12, and 13 (FGR-11, FGR-12, FGR-13) Dose Conversion Factors (DCFs) for inhalation, submersion, and ground shine. FGR-12 DCF values are used for submersion and ground shine. In addition to the inhalation 50-year Committed Effective Dose Equivalent DCFs, acute (1, 4, 30 days) DCFs are available for estimating deterministic effects. This acute mode is used for estimating the immediate radiological impact associated with high-acute radiation doses (applicable target organs are the lung, small intestine wall, and red bone marrow).

HotSpot Software Tools

Four general software programs—Plume, Explosion, Fire, and Resuspension—estimate downwind radiological effects following the release of radioactive material resulting from a continuous or puff release, explosive release, fuel fire, or an area contamination event. Additional tools deal specifically with the release of plutonium, uranium, and tritium to expedite an initial assessment of accidents involving nuclear weapons.

The FIDLER Tool is a tool for calibrating radiation survey instruments for ground-survey measurements and initial screening of personnel for possible plutonium uptake in the lung.

The Nuclear Explosion Tool estimates the effects of a surface-burst nuclear weapon. These include prompt effects (neutron and gamma, blast, and thermal) and fallout information. Fallout includes arrival time, dose rate at arrival time, and integrated dose contours for several time periods e.g., first 6 hours, first day, first week, etc.

HotSpot 3.0 is now available!
Please Register for your free download.

Hotspot User's Guide (pdf document)


Submitting Questions or Problem Reports

Have you identified a HotSpot problem or have questions? Please submit your problem or question so our support team can address your issue.

You may also email HotSpot support directly.