RISKBIN is a WINDOWS 95/98 based program that has been developed for technical and project risk and uncertainty assessment. Given the frequency of mishaps and various sequences of events that could lead to potential failures (in case of nuclear power plants, various core damage sequences), RISKBIN can be used to assess the risk, including the uncertainties associated with various risk indices, by assessing the probabilities of breaching the risk envelope (in the case of a nuclear accident, containment failure probabilities) using a multi-branch, multi-node event tree. The event tree allows for dependencies between various nodal events and it includes a WINDOWS-based, user specified algorithm for binning various end-states into more manageable sets of outcomes, for use in risk integration and/or other applications.

The program is of use in technical risk assessment (nuclear reactors, industrial and process systems, space craft, etc.), a scenario-based project and financial/ investment risk assessment, provided the various decision branches (scenario driven) are known, and probabilities for events or decision alternatives can be assigned.

RISKBIN allows assigning probability distributions (in the form of user defined probability distribution functions of general forms) for each "uncertain" variable, scenario element or event branch. It includes an algorithm for propagation of uncertainties through a risk model based on an extremely efficient stratified Monte Carlo Sampling technique.

RISKBIN results/outputs can also be cast in the form of point values or uncertainty distributions (if the uncertainty option is used).

The RISKBIN application consists of several parts implementing the various steps in the event tree analysis. These parts are interrelated and provide an interface to external programs used for producing additional data required for different options of calculations. The logical application model is shown above.

The logical application model enables the user to work on several analyses at the same time (multi-document time). The data entered, imported and generated during the work with the event tree will be stored in a data file and they will be retrieved and saved as necessary for implementing the calculation algorithms. The RISKBIN application will access the tables in the data file through a standard interface.

The event tree is generated as a Windows tree control. The most common implementation of this control is the directory listing in Windows Explorer. The nodes of the tree can be expanded and collapsed by a mouse click and additional information can be displayed by selecting a node.

Every displayed branch contains the next event, with different probabilities. (The order of the events is given when entering events.) When the probability of the event is less than the cut off criteria the branch will not be populated further only the last remaining branch will be displayed.

In addition to providing the software executable, ERI could also provide on- or off-site training for RISKBIN use and application, if required. RISKBIN is fully documented and can also be implemented without any formal training.