A nuclear reactor is disclosed including a reactor core and a reflector assembly surrounding the reactor core. The reflector assembly includes a stationary reflector component including a graphite support structure comprising a plurality of channels defined therein and a plurality of beryllium-oxide pins positioned in the channels.

A Control Neutron Absorber (CNA) assembly for a microreactor that produces nuclear energy is disclosed. The CNA assembly includes a housing, a CNA rod, and a burnable absorber. The housing includes an inner housing and an outer housing. The inner housing is configured to receive a CNA rod. The outer housing extends coaxially with the inner housing and is positioned radially outward and offset from the inner housing defining a cavity therebetween. The CNA rod includes a neutron absorbing rod including a first neutron absorbing material. The neutron absorbing rod is positioned within the inner housing and is configured to move axially relative to the inner housing. The burnable absorber includes a second neutron absorbing material, exhibits a neutron absorbing strength that is less than that of the neutron absorbing rod, is positioned within the inner housing, and is configured to receive the neutron absorbing rod therein.

Various example embodiments are directed towards an improved control drum, as well as systems, apparatuses, and/or methods for operating a nuclear reactor with a plurality of improved control drums. The control drum includes an outer shell, an inner shell, a plurality of tubes, the plurality of tubes including at least one neutron absorbing tube and at least one neutron scattering tube, and at least one baffle plate arranged between the outer shell and the inner shell, the at least one baffle plate including a plurality of perforations, and at least one perforation of the plurality of perforations configured to support a tube of the plurality of tubes.

Various example embodiments are directed towards an improved control drum, as well as systems, apparatuses, and/or methods for operating a nuclear reactor with a plurality of improved control drums. The control drum includes an outer shell, an inner shell, a plurality of tubes, the plurality of tubes including at least one neutron absorbing tube and at least one neutron scattering tube, and at least one baffle plate arranged between the outer shell and the inner shell, the at least one baffle plate including a plurality of perforations, and at least one perforation of the plurality of perforations configured to support a tube of the plurality of tubes.

Various example embodiments are directed towards an improved control drum, as well as systems, apparatuses, and/or methods for operating a nuclear reactor with a plurality of improved control drums. The control drum includes an outer shell, an inner shell, a plurality of tubes, the plurality of tubes including at least one neutron absorbing tube and at least one neutron scattering tube, and at least one baffle plate arranged between the outer shell and the inner shell, the at least one baffle plate including a plurality of perforations, and at least one perforation of the plurality of perforations configured to support a tube of the plurality of tubes.

The present disclosure relates to device for use in a fuel assembly of a nuclear power plant, the device comprises at least one rod, each rod comprises a plurality of containers having a space being filled with material to be activated, characterized in that the device further comprises a flow restrictor for a fuel assembly of a nuclear power plant comprising a plurality of fingers adapted to extend respectively into a control rod guide tube of the fuel assembly when the flow restrictor is inserted into the fuel assembly, wherein the at least one rod is connected to a finger of the flow restrictor, wherein the containers are arranged subsequently in a direction of the longitudinal axis of the respective rod.

The present disclosure relates to device for use in a fuel assembly of a nuclear power plant, the device comprises at least one rod, each rod comprises a plurality of containers having a space being filled with material to be activated, characterized in that the device further comprises a flow restrictor for a fuel assembly of a nuclear power plant comprising a plurality of fingers adapted to extend respectively into a control rod guide tube of the fuel assembly when the flow restrictor is inserted into the fuel assembly, wherein the at least one rod is connected to a finger of the flow restrictor, wherein the containers are arranged subsequently in a direction of the longitudinal axis of the respective rod.

The purpose of the present invention is to provide a neutron-absorbing material which has high neutron absorption performance, is less apt to suffer structural degradation caused by irradiation with neutrons or rays, and has satisfactory water resistance. The glass composition according to the present invention is characterized by containing Gd2O3, B2O3, CeO2, and Bi2O3 when the components are expressed in terms of oxide, the total amount of Gd2O3 and B2O3 being 65 mol % or greater in terms of oxide amount.

The purpose of the present invention is to provide a neutron-absorbing material which has high neutron absorption performance, is less apt to suffer structural degradation caused by irradiation with neutrons or rays, and has satisfactory water resistance. The glass composition according to the present invention is characterized by containing Gd2O3, B2O3, CeO2, and Bi2O3 when the components are expressed in terms of oxide, the total amount of Gd2O3 and B2O3 being 65 mol % or greater in terms of oxide amount.

A gray control rod having a neutron absorber comprising terbium and dysprosium is provided. The neutron absorber comprises at least one first component and at least one second component, the reactivity worth of the first component increases as the service time of the neutron absorber increases, the reactivity worth of the second component decreases as the service time of the neutron absorber increases; the reactivity worth of the neutron absorber varying no more than 15% within the service time of the neutron absorber. By using the first component and the second component to form the neutron absorber, and adjusting the proportion of the respective components in the neutron absorber, the neutron absorber having a substantially planar reactivity worth loss characteristic can be obtained. The gray control rod and the assembly having required reactivity controlling ability can be obtained by increasing or decreasing the material dosage of the neutron absorber.