No abstract available

[en] Short communication

[en] A set of algorithms has been developed to support dosimetric and transport calculations. These subroutines read a radionuclide data file and prepare a decay chain showing branching fractions and radioactive half-lives of each member. One application of these subroutines has been their implementation as a set of FORTRAN subroutines for application in the PREREM code (Ryan and Fields, 1981). Recent use of these subroutines in stand-alone form required their expansion to print branching fractions. An expanded data set based on ICRP-38 radionuclide data (ICRP, 1983) was also prepared. This subroutine package is called Radionuclide Origin and Ontogeny Tracing Subroutines (ROOTS). The package is intended for execution on a Digital Equipment Corporation PDP-10 Computer System, and may require modification to run on other machines. 6 refs

[en] The main features of JAERI-Conversion are briefly given. The adaptation of cycle 1 and the updating procedure, as also errors detected during updating are then presented

[en] A subroutine for Taylor series solutions of systems of ordinary linear differential equations is descriebed. It uses the old idea of Lie series but allows simple implementation and is time-saving for symbolic manipulations. (orig.)

No abstract available

[en] Short communication

[en] The REDIS program is based upon simulation of the direct type (no variance reduction). The program can be used for any system in principle, and it is particularly designed for standby systems taking into consideration the various kinds of errors that can cause failure during both operating and standby conditions. The program is described with emphasis on the particular aspects of the simulation models, illustrating the ability of the program to consider details of systems and its flexibility. The different kinds of faults that occur in practice are described and categorized. The main categories of faults are STOPPAGE faults, which can lead to stoppage of operation, and BLOCKING faults, which can cause failure to start on demand. Various types of faults can occur within each of the main categories, the two main types being the time dependent and the activation dependent types. The method used to incorporate the various kinds of faults, dependencies between faults and uncertainties in the data, are described. In standby systems, groups of components have common operation and standby periods. A description is presented of the model used for simulation of STOPPAGE and BLOCKING of such groups. The program includes a model for the simulation of periodic testing of specified groups of faults, and for renewal of worn-out components. An example calculation on a simple system is presented, including input and output. The experience with the program is summarized. (author)

[en] System thermal-hydraulic parameters and simulated, using the best-estimate system code(RELAP5/MOD1/NSC), based upon the sequence of events for the KNU1( Korea Nuclear Unit 1) loss of offsite power transient at 77.5% power which occurred on June 9,1981. The results are compared with the actual plant transient data and show good agreements. After the flow coastdown following the trips of both reactor coolant pumps, the establishment of natural circulation by the temperature difference between the hot and the cold legs is confirmed. The calculated reactor coolant flowrate closely approximate the plant data indicating the validity of relevant thermal-hydraulic models in the RELAP5/MOD1/NSC. Results also show that the sufficient heat removal capability is secured by the appropriate supply of the auxiliary feedwater without the operation of S/G PORVs. In addition, a scenario accident at full power, based upon the same sequence of events described above, is also analysed and the results confirmed that the safety of KNU1 is secured by the appropriate operation of the S/G PORVs coupled with the supply of auxiliary feedwater which ensures sufficient heat removal capability. The characteristics of the non-safety related components such as the turbine stop valve closing time, S/G PORV setting etc. are recognized to be important in the transient analyses on a bestestimate basis. (Author)

[en] The principles of the representation of dynamic data structures within the modular system RSYST-II are described. The identification of data blocks and data elements is carried out with the help of hierarchical data structures. Therefore, a simple formulation of complex burn-up problems is possible. The scheme of identification permits the user to define table functions simply. The consequent application of this scheme leads to a general generation and representation module for different data block types and to a data-structure independent programming of modules. (orig.)