Specific features of the WWR-K reactor horizontal channel as applied to BNCT

For several years the studies related to adaptation of one of the horizontal channels of the WWR-K reactor in view of treatment of malignant tumors by neutron capture therapy techniques are carried out at the Institute of Nuclear Physics in the frame of the republican research program 'Development of Nuclear Power in Kazakhstan'. The need in NCT in Kazakhstan is rather urgent, because many people suffer from cancer. The neutron capture therapy (NCT) is widely used over the world but in special medical reactors. An idea to use the research nuclear reactor for (medical purposes seems to be attractive, because financial expenditures for reactor operation in this case will be considerably lower. The reactor experimental horizontal channel GK-1, transporting the neutron beam from the reactor core via biological shield to the reactor hall, was chosen for NCT goals. The neutron beam neutronic parameters over the channel length have been estimated with and without the neutron guide installed in the reactor core. The neutron guide is to increase the neutron flux density at the channel exit and to reduce the beam gamma component. Prior to experimenting, the corresponding calculations were carried out by means of the computer codes as well as modeling experiments in the critical assembly (zero-power reactor). The following outcomes have been obtained: The patterns of the thermal/fast neutron flux density distribution over the length of the horizontal channels have been found for various reactor power levels and various versions of neutron guide. The thermal/fast neutron flux density at the channel exit comprise 1.2·109/5·108 neutrons cm-2c-1. The lead neutron guide, installed in the reactor core, is found to double the thermal neutron flux density at the channel exit. Further studies imply participation of a multi-discipline team of researchers (physicists, biologists, radiologists, oncologists, etc.), and it seems that the appropriate international NCT project will be the best chance. As for the WWR-K reactor, the chosen horizontal channel is a good candidate for a role of the test site of both various physical tricks needed for formation of a required neutron beam and the medical and biological techniques