A neutron absorbing insert for use in a fuel rack. In one aspect, the insert includes: a plate structure having a first wall and a second wall that is non-coplanar to the first wall; the first and second walls being formed by a single panel of a metal matrix composite having neutron absorbing particulate reinforcement that is bent into the non-coplanar arrangement along a crease; and a plurality of spaced-apart holes formed into the single panel along the crease prior to bending.

A nuclear fuel decay heat utilization system usable for space heating in one embodiment comprises a nuclear generation plant building housing a spent fuel pool containing submerged fuel assemblies which emit decay heat that heats the pool. Plural fluidly isolated but thermally coupled heat removal systems comprising pumped flow loops operate in tandem to absorb thermal energy from the heated pool water, and transfer the thermal energy through the systems in a cascading manner form one to the next to a final external heat sink outside the plant building from which the heat is rejected to the ambient environment. A programmable controller operably regulates the intake and flowrate of water from the heat sink into the heat removal systems and monitors ambient air temperature inside to building. The flowrate is regulated to maintain a preprogrammed building setpoint air temperature by increasing fuel pool water temperature to a maximum permissible limit.

A nuclear fuel decay heat utilization system usable for space heating in one embodiment comprises a nuclear generation plant building housing a spent fuel pool containing submerged fuel assemblies which emit decay heat that heats the pool. Plural fluidly isolated but thermally coupled heat removal systems comprising pumped flow loops operate in tandem to absorb thermal energy from the heated pool water, and transfer the thermal energy through the systems in a cascading manner form one to the next to a final external heat sink outside the plant building from which the heat is rejected to the ambient environment. A programmable controller operably regulates the intake and flowrate of water from the heat sink into the heat removal systems and monitors ambient air temperature inside to building. The flowrate is regulated to maintain a preprogrammed building setpoint air temperature by increasing fuel pool water temperature to a maximum permissible limit.

A module for storing high level radioactive waste includes an outer shell, having a hermetically closed bottom end, and an inner shell forming a cavity and being positioned inside the outer shell to form a space therebetween. At least one divider extends from the top to the bottom of the inner shell to create a plurality of inlet passageways through the space, each inlet passageway connecting to a bottom portion of the cavity. A plurality of inlet ducts each connect at least one of the inlet passageways and ambient atmosphere, and each includes an inlet duct cover affixed atop a surrounding inlet wall, the inlet wall being peripherally perforated. A removable lid is positioned atop the inner shell and has at least one outlet passageway connecting the cavity and the ambient atmosphere, the lid and the top of the inner shell being configured to form a hermetic seal therebetween.

A module for storing high level radioactive waste includes an outer shell, having a hermetically closed bottom end, and an inner shell forming a cavity and being positioned inside the outer shell to form a space therebetween. At least one divider extends from the top to the bottom of the inner shell to create a plurality of inlet passageways through the space, each inlet passageway connecting to a bottom portion of the cavity. A plurality of inlet ducts each connect at least one of the inlet passageways and ambient atmosphere, and each includes an inlet duct cover affixed atop a surrounding inlet wall, the inlet wall being peripherally perforated. A removable lid is positioned atop the inner shell and has at least one outlet passageway connecting the cavity and the ambient atmosphere, the lid and the top of the inner shell being configured to form a hermetic seal therebetween.

A method of retrofitting a spent nuclear fuel system with a neutron absorbing apparatus. The method includes inserting a neutron absorbing apparatus into a first cell of an array of cells each configured to hold a spent nuclear fuel assembly. The neutron absorbing apparatus includes a first wall and a second wall supported by a corner spine to form a chevron shape and a first locking tab protruding outwardly from the first wall towards a first cell wall of the first cell. The method includes cutting a half-sheared second locking tab in the first cell wall of the first cell adjacent to and above the first locking tab of the neutron absorbing apparatus. Finally, the second locking tab is positioned to locking engage the first locking tab to retain the neutron absorbing apparatus in the first cell during removal of one of the fuel assemblies from the first cell.

A method of retrofitting a spent nuclear fuel system with a neutron absorbing apparatus. The method includes inserting a neutron absorbing apparatus into a first cell of an array of cells each configured to hold a spent nuclear fuel assembly. The neutron absorbing apparatus includes a first wall and a second wall supported by a corner spine to form a chevron shape and a first locking tab protruding outwardly from the first wall towards a first cell wall of the first cell. The method includes cutting a half-sheared second locking tab in the first cell wall of the first cell adjacent to and above the first locking tab of the neutron absorbing apparatus. Finally, the second locking tab is positioned to locking engage the first locking tab to retain the neutron absorbing apparatus in the first cell during removal of one of the fuel assemblies from the first cell.

A system for externally cooling a radiation shielded cask containing heat-emitting high level radioactive waste such as spent nuclear fuel. The system includes the cask defining an internal cavity configured to hold an unshielded canister containing the spent nuclear fuel. An annular cooling water header extends circumferentially around the entire circumference of the cylindrical sidewall of the cask. The header comprises plural dispensing outlets which direct cooling water onto the cask, thereby wetting the entire sidewall of the cask. The cooling water provides an external heat sink for absorbing the heat emitted through the external wall surface of the cask generated by the spent nuclear fuel. In various embodiments, the cooling water header may have a continuous annular structure, or be formed by two or more header segments. The header may be supported directly from the cask by detachably mounted brackets.

A method of retrofitting a spent nuclear fuel system with a neutron absorbing apparatus. The method includes inserting a neutron absorbing apparatus into a first cell of an array of cells each configured to hold a spent nuclear fuel assembly. The neutron absorbing apparatus includes a first wall and a second wall supported by a corner spine to form a chevron shape and a first locking tab protruding outwardly from the first wall towards a first cell wall of the first cell. The method includes cutting a half-sheared second locking tab in the first cell wall of the first cell adjacent to and above the first locking tab of the neutron absorbing apparatus. Finally, the second locking tab is positioned to locking engage the first locking tab to retain the neutron absorbing apparatus in the first cell during removal of one of the fuel assemblies from the first cell.

A method of retrofitting a spent nuclear fuel system with a neutron absorbing apparatus. The method includes inserting a neutron absorbing apparatus into a first cell of an array of cells each configured to hold a spent nuclear fuel assembly. The neutron absorbing apparatus includes a first wall and a second wall supported by a corner spine to form a chevron shape and a first locking tab protruding outwardly from the first wall towards a first cell wall of the first cell. The method includes cutting a half-sheared second locking tab in the first cell wall of the first cell adjacent to and above the first locking tab of the neutron absorbing apparatus. Finally, the second locking tab is positioned to locking engage the first locking tab to retain the neutron absorbing apparatus in the first cell during removal of one of the fuel assemblies from the first cell.