[en] The ASSIST package (A Structured Storage and Input Syntax Tool) provides for Fortran programs a means for handling data structures more general than those provided by the Fortran language, and for obtaining input to the program from a file or terminal according to specified syntax rules. The syntax-controlled input can be interactive, with automatic generation of prompts, and dialogue to correct any input errors. The range of syntax rules possible is sufficient to handle lists of numbers and character strings, keywords, commands with optional clauses, and many kinds of variable-format constructions, such as algebraic expressions. ASSIST was developed for use in two large programs for the analysis of safety of radioactive waste disposal facilities, but it should prove useful for a wide variety of applications. (author)

[en] The transient fuel performance code TRAFIC, originally developed for fast reactor work by J.R.Matthews, has been converted for modelling PWR pins. This report gives details of how to use the PWR version, as it stood at December, 1982. Preparation of input data, interpretation of the printed output, and the use of dump datasets for re-starting or plotting, are described. (author)

[en] MASCOT and MOP are computer programs for performing probabilistic safety assessment calculations for underground disposal of radioactive wastes. This report, which is Part F2 of a multi-part report on MASCOT and MOP, explains how to run the programs on a Silicon Graphics Workstation, using commands that have been provided in the form of Unix scripts. (author)

[en] MASCOT and MOP are computer programs for modelling the consequences of the disposal of radioactive waste in underground repositories. This report, which is Part F of a multi-part report on MASCOT and MOP, explains how to run the programs on the Cray-2 computer at the AEA Harwell Laboratory, using commands that have been provided in the form of UNIX scripts. (author)

[en] MOP is a post-processor for the probabilistic safety assessment program MASCOT, which models the consequences of the disposal of radioactive waste. This document provides a general description of the capabilities of the MOP program, together with a comprehensive guide to the MOP user command language that exists in version 2E. MOP is able to calculate and present various statistical measures of the modelled radiological consequences, in both printed and graphical form. The results of intermediate analyses can be saved from one MOP job to the next, and this allows MOP to be used as many times as desired to process the results of the same MASCOT job. MOP can work with the quantities passed to it from the MASCOT job or with new quantities, defined and calculated according to individual requirements. This is usually done by transforming the MASCOT quantities using algebraic expressions. (author)

[en] Probabilistic calculations using the computer code MASCOT-3 played a major role in post-closure safety assessment studies carried out for UK Nirex Ltd during 1988. This code estimates risk using mathematical models of the system in which many parameters are subject to uncertainty, described by probability distribution functions. Comparatively simple models, with no explicit time-dependency, are used. Laplace transform techniques are used to calculate solutions efficiently. Very general types of correlated parameter distributions may be specified in the form of algebraic formulae. Details are given of the sub-models used for release of radionuclides from the vault, transport through the geosphere, and transmission in the biosphere to produce doses to Man. Altogether, some 13 combinations of disposal concept and geological environment were treated using MASCOT-3. Some example results are shown, and the overall conclusions reached are listed. 3 refs., 5 figs

[en] UK Nirex Ltd is planning the deep geological disposal of intermediate- and low-level radioactive wastes. A site close to Sellafield in Cumbria in the north-west of England has been selected for evaluation, and an extensive program of site characterization is underway. In support of this program of characterization, and in preparation for presentation of a post-closure radiological safety case, performance assessment using mathematical modeling has been carried out by the Disposal Safety Assessment Team at AEA Technology, on behalf of UK Nirex Ltd. This paper describes recent developments of the assessment models relating to the groundwater pathway for return of radionuclides to the environment

[en] This report focuses on the biosphere modelling aspects of the assessment of the radiological impact of the disposal of radioactive waste in greater detail. Seven exposure pathways are modelled: drinking water, freshwater fish, meat, milk and grain consumption as well as external gamma irradiation and contaminated dust inhalation. The accumulation of radionuclides, released in groundwaters, in the upper soil is also modelled. The objectives of this Level 1b exercise can be summarized as follows: 1 to gain experience in the application of probabilistic systems assessment methodology to transport and radiological exposure sub-models for the biosphere and hence to methods of estimating the total risk to individuals or groups of individuals; 2 to contribute to the verification of biosphere transport and exposure sub-models; 3 to investigate the effects of parameter uncertainty in the biosphere transport and exposure sub-models on the estimate of mean dose to individuals exposed via several exposure pathways

[en] MASCOT and MOP are computer programs whose principal purpose is to model the consequences of the disposal of radioactive waste in underground repositories. The Probabilistic Safety Assessment method may be used, or deterministic calculations with all parameters taking fixed values, may be performed. This Report, which is Part A of a multi-part Report on MASCOT and MOP, gives an overview of the two programs. It refers to new versions, MASCOT 3C00 and MOP 3A00, that have been prepared to allow running on platforms ranging from workstations to supercomputers. (Author)

[en] MASCOT and MOP are computer programs for modelling the consequences of the disposal of radioactive waste in underground repositories, using either the Probabilistic Safety Assessment method or deterministic calculations with all parameters taking fixed values. This report, which is Part A of a multi-part report on MASCOT and MOP, gives an overview of the two programs. It refers to version 3B05 of MASCOT and version 2E01 of MOP. The range of models that can be used in a MASCOT calculation are described, both in general terms, and by describing the specific submodels available. The flexible provisions for assigning values or probability distributions to model parameters are described. (Author)