The UK Health Security Agency ( UKHSA ) Radiation Assessments Department has responsibility for assessment of the radiological consequences of potential and planned releases of radioactive material into the environment . It has developed two software programmes to assist with such assessments : PACE ( Probabilistic Accident Consequences Evaluation ) for assessing the consequences of an accidental release of radioactive material to the atmosphere and PC-CREAM ( Consequences of Releases to the Environment Assessment Methodology ) for assessing the consequences of planned routine discharges to the atmosphere , rivers and seas . PACE was developed for emergency planning and preparedness and is not used in emergency response .
Other software called ADMS ( Atmospheric Dispersion Modelling System ) developed by Cambridge Environmental Research Consultants in conjunction with the UK Met Office , National Power and the University of Surrey is also used in the UK to model routine releases and planned discharges of radionuclides . ADMS is not used for emergency response .
The US Lawrence Livermore National Laboratory developed the HotSpot Health Physics codes ( free to download ). These provide a first-order approximation of the radiation effects associated with the atmospheric release of radioactive materials and were created to equip emergency response personnel and planners with a fast , field-portable set of software tools for evaluating incidents . The software is also used for the safety analysis of facilities handling radioactive material . The HotSpot codes are designed for short-range ( less than 10 km ) and short-term ( less than a few hours ) predictions .
For emergency response following a fire or explosion , different software is used to carry out some initial form of plume prediction , using data on the source of radioactive material and the meteorological conditions at the time . Depending on the nature of the incident , large particles could be deposited over a relatively small area , or contaminated smoke over a wider area . Several models for plume prediction have been developed and refined over the years by various governments .
In the UK , different organisations will use the same atmospheric dispersion models in developing their advice as input into the Government ' s SAGE ( Scientific Advisory Group for Emergencies ) group , which would advise on the national response to a nuclear power plant accident . The modelling framework used is called JAM ( Joint Agency Modelling ).
Operators , environment agencies and food standards agencies in the UK tend to use Gaussian plume atmospheric dispersion models . The UK Met Office and UKHSA use a Lagrangian particle model called NAME in developing advice as input into the Science and Technical Advice Cell ( STAC ) and the local response to a nuclear accident . In contrast to Gaussian plume models , use of a Lagrangian particle model requires no assumptions regarding the shape of the concentration distribution . JAM involves more than just atmospheric dispersion modelling , for example radiological dose modelling . It can be used by other organisations under licence .
Following an emergency incident , modelling is necessary to guide monitoring teams where to monitor , including how to approach the radioactive footprint safely . Feedback from monitoring teams will allow modellers to update their outputs and advise priorities for further monitoring , minimising the risk to teams already deployed in areas with high levels of radiation . Hotspots of radioactive material could be present depending on the nature of the incident , such as an explosion , or due to the nature of the terrain or weather . Modelling can be resolved to account for the patchy nature of deposition due to rain showers but may or may not be able to predict the specific locations of hotspots accurately .
The type of monitoring obviously depends on the nuclides involved , but instruments tend to be similar to those used for land contamination .
16 Radiation Protection Today www . srp-rpt . uk