Improvement of a three dimensional core deformation analysis code

Sawada, Shusaku*; not registered; not registered

"HIBEACON", which is a three dimensional core deformation analysis code for the experimental fast reactor "JOYO", had been modified in order to expand the code's functions for planning a long-term operation and managing the operation of "JOYO", and to analyse the core deformation characteristics speedily and accurately. In this study, "HITETRAS", which is a code for calculating temperatures and fast neutron fluxes on wrapper tubes, has been modified in order for it to correspond with the modification of "HIBEACON". And, the core deformation analysis on "JOYO" MK-III has been performed with those modified codes. Results of this study are as follows: (1) Improvement of core deformation analysis code. (a) Modification of function of "HITETRAS" to output temperatures and neutron fluxes. The method to output wrapper tubes' temperatures and neutron fluxes has been modified corresponding to the modification of "HIBEACON". (b) Addition of ability to alter program size of "HITETRAS". An ability to alter the program size has been added to "HITETRAS" by using INCLUDE statement and PARAMETER statement of FORTRAN language. (c) Modification of "HIBEACON". Following modifications, which are required for analysis on "JOYO" MK-III, have been perfomed. (1) alteration of calculation method for gap clearance between wrapper tubes. (2) addition of function for outputting elements of free bowing deformation (3) addition of function for selecting items to be output on list (2) Core deformation analysis on "JOYO" MK-III. "JOYO" MK-III will have different core characteristics from MK-II because of its higer neutron flux feature, two core regions, wider irradiation space, and so on. So, the core deformation behavior of "JOYO" MK-III has been analysed with the modified codes above-mentioned, and it has been clarified that there is no problem on the core integrity of MK-III from the view point of the core deformation.