摘要:
An integral pressurized water reactor (PWR) comprises: a cylindrical pressure vessel including an upper vessel section and a lower vessel section joined by a mid-flange; a cylindrical central riser disposed concentrically inside the cylindrical pressure vessel and including an upper riser section disposed in the upper vessel section and a lower riser section disposed in the lower vessel section; steam generators disposed inside the cylindrical pressure vessel in the upper vessel section; a reactor core comprising fissile material disposed inside the cylindrical pressure vessel in the lower vessel section; and control rod drive mechanism (CRDM) units disposed inside the cylindrical pressure vessel above the reactor core and in the lower vessel section. There is no vertical overlap between the steam generators and the CRDM units.
摘要:
A nuclear reactor is surrounded by a reactor radiological containment structure. A spent fuel pool is adjacent to and outside of the reactor radiological containment structure. The spent fuel pool may also be contained in its own radiological containment structure. A valved steam pipe runs from the reactor containment structure into the spent fuel pool. During a reactor containment overpressure event, a valve on the steam pipe is opened to allow steam from the reactor containment structure to discharge into (e.g. sparge into) the spent fuel pool. In an alternative embodiment suitable for use in a two-pack nuclear power plant, steam pipes connect the reactor radiological containment structures of the two nuclear reactors, and isolation valves on the steam pipes are opened in response to an overpressure condition in one reactor containment structure in order to discharge steam into the other reactor containment structure.
摘要:
A pressurized water reactor (PWR) includes a pressure vessel containing a nuclear reactor core immersed in primary coolant water, control rod assemblies (CRA's), and control rod drive mechanisms (CRDM's) operating the CRA's. The reactor core has axially varying 235U enrichment and/or axially varying burnable poison concentration. A CRDM controller controls the CRA's over a burn-up cycle that does not include fuel assembly shuffling and is divided into a plurality of burn-up intervals. The CRDM controller is configured to, for each burn up interval: position the CRA's in accordance with a CRA pattern defining a set of fixed positions for the CRA's except for a sub-set of CRA's designated by the CRA pattern as floating CRA's, and control power level of the PWR by adjusting the floating CRA's without not adjusting the CRA's not designated as floating CRA's. The primary coolant water optionally does not contain soluble neutron poison.
摘要:
A nuclear power plant comprises a pressurized water reactor (PWR) and a steam generator driving a turbine driving an electric generator. A condenser condenses steam after flowing through the turbine. Responsive to a station blackout, the nuclear power plant is electrically isolated and a bypass valve is opened to convey bypass steam flow from the steam generator to the condenser without flowing through the turbine. The thermal power output of the PWR is gradually reduced over the transition time interval. After opening, the bypass valve is gradually closed over the transition time interval. A supplemental bypass valve may also be opened responsive to the station blackout to convey supplemental bypass steam flow from the steam generator to a feedwater system supplying secondary coolant feedwater to the steam generator. The supplemental bypass steam flow does not flow through the turbine and does not flow through the condenser.
摘要:
A control rod guide frame has a central passage of constant cross-section as a function of position along a central axis that passes through the central passage. The central passage is sized and shaped to guide a traveling assembly including at least one control rod as it moves along the central axis. The control rod guide frame comprises at least two radial guide frame sections secured around and defining the central passage. Each radial guide frame section may comprise an extruded radial guide frame section, which may be made of extruded steel. The central passage may include control rod guidance channels parallel the central axis and machined into the extruded radial guide frame sections. The at least two radial guide frame sections may be interchangeable. In some embodiments the at least two radial guide frame sections consist of between four and eight radial guide frame sections.
摘要:
A nuclear reactor including a lateral seismic restraint with a vertically oriented pin attached to the lower vessel head and a mating pin socket attached to the floor. Thermally insulating materials are disposed alongside the exterior surface of a lower portion of the reactor pressure vessel including at least the lower vessel head.
摘要:
A pressure vessel comprises an upper vessel section and a lower vessel section. A nuclear reactor core comprises fissile material contained in a containing structure and disposed in the lower vessel section. Upper internals are disposed in the lower vessel section above the nuclear reactor core. The upper internals include at least guide frames and internal control rod drive mechanisms (CRDMs) with CRDM motors mounted on a suspended support assembly including a plurality of hanger plates connected by tie rods. The plurality of hanger plates includes a lowermost hanger plate having alignment features configured to align the upper internals with the containing structure that contains the nuclear reactor core.
摘要:
A nuclear reactor includes a nuclear reactor core comprising fissile material disposed in a reactor pressure vessel having vessel penetrations that exclusively carry flow into the nuclear reactor and at least one vessel penetration that carries flow out of the nuclear reactor. An integral isolation valve (IIV) system includes passive IIVs each comprising a check valve built into a forged flange and not including an actuator, and one or more active IIVs each comprising an active valve built into a forged flange and including an actuator. Each vessel penetration exclusively carrying flow into the nuclear reactor is protected by a passive IIV whose forged flange is directly connected to the vessel penetration. Each vessel penetration carrying flow out of the nuclear reactor is protected by an active IIV whose forged flange is directly connected to the vessel penetration. Each active valve may be a normally closed valve.
摘要:
A nuclear reactor coolant pump (RCP) comprises a stator and a rotating assembly including a rotor, an impeller, and a flywheel configured to rotate about an axis of rotation in response to the stator being electrically energized. The flywheel comprises a first material (such as stainless steel) and has a plurality of mutually parallel tubular openings filled with a second material that is denser than the first material (such as tungsten or tungsten alloy). In some embodiments the mutually parallel tubular openings are cylindrical openings, and are filled with the second material comprising cylindrical rods. In a nuclear reactor including a reactor pressure vessel and a nuclear reactor core comprising fissile 235U disposed in the reactor pressure vessel, the RCP is suitably disposed on or in the reactor pressure vessel with the impeller of the RCP arranged to engage coolant water disposed in the reactor pressure vessel.