Fast neutron irradiation causes embrittlement of the reactor pressure vessel (RPV)
material; therefore, it may end operation life before design lifetime. Well-known
method to recuperate crystal lattice dislocations is annealing. In the current version
of thorium fueled supercritical water-cooled reactor (SCWR) design proposed by the
Institute of Nuclear Technology at Budapest University of Technology and Economics
(BME NTI), the supercritical fluid flows upward between the core barrel and the inner
surface of the RPV thereby, the coolant would keep the RPV's temperature at similar
to 500 degrees C. This reverse coolant flow direction would decrease the embrittlement
of RPV by constant annealing. To minimize the fast neutron flux increase, a relatively
thin shielding connected to the inner surface of the barrel could be used. This presents
fast neutron irradiation analysis, performed for different settings of the shielding
to reduce fast neutron flux reaching the inner surface of RPV.
