3. DESCRIPTION OF PROGRAM OR FUNCTION
Penetrations such as an entrance, supply / exhaust ducts and pipes go through walls in nuclear facilities. They are generally made as bent structures in order to decrease leakage radiation (streaming) through them. However it is very difficult to evaluate the streaming radiation because the structures are complex. The DUCT code calculates duct-streaming radiation of neutrons and photons with a semi-empirical formula, was developed in 1988 for the purpose of penetration designs. This code can treat the main types of penetrations i.e., cylindrical duct, rectangular duct, annulus and slit. This code is applicable to designs of penetrations in nuclear power plants, fusion reactor facilities, accelerator facilities, and so on, because albedo data for gamma-rays up to 10 MeV and neutrons up to 3 GeV are implemented in it. Since then, this code has been updated by simplification of input data, addition of functions to deal with bent ducts, and so on, and the DUCT-II code was developed. In 1998 -2001, the DUCT-III code was developed by adding the following functions to the DUCT-II code to allow application to high energy accelerator facilities, further simplification of input data, and so on.
(1) Addition of high-energy neutron albedo data (maximum energy 3GeV)
(2) Addition of a function to calculate wall scattered radiation
(3) Addition of typical source spectra
(4) Addition of a point kernel program PKN-H
(5) Optional setup of source position
(6) Development of a Visual Basic version
