A main pump shaft seal water injection system of a nuclear power plant includes a jet pump, a high pressure cooler, a hydrocyclone, valves and a main connection pipeline outside of a main pump, and an auxiliary pump and an internal flow path inside the main pump. Inner and outer flow paths of the main pump are connected with a shaft seal water injection hole and a high temperature water drainage hole. The main connection pipeline is connected between an upper filling water pipeline and a shaft seal water injection hole. A bypass pipeline connected with the jet pump, the high pressure cooler and the hydrocyclone, the main connection pipeline is provided with a normally open main pipeline isolating valve. The bypass pipeline allows low temperature upper filling water in the RCV system to enter the shaft seal water injection hole of the main flange directly.

Claimed embodiments of the integral nuclear reactor relate to nuclear technology and can be used in reactors with different types of heat transfer fluids with a high boiling point, such as, for example, liquid metals, molten salts, etc. Design features of the invention embodiments claimed which have a coil heat exchanger sectioned along the secondary heat carrier circuit provides for an improvement in technical and economic features due to a decrease in metal consumption of the reactor; efficient use of the internal volume of the reactor; improved safety in case of the heat exchanger tube leaks; enabling the removal of residual heat during the time after removal of the protective plug before fuel discharge operations.

Claimed embodiments of the integral nuclear reactor relate to nuclear technology and can be used in reactors with different types of heat transfer fluids with a high boiling point, such as, for example, liquid metals, molten salts, etc. Design features of the invention embodiments claimed which have a coil heat exchanger sectioned along the secondary heat carrier circuit provides for an improvement in technical and economic features due to a decrease in metal consumption of the reactor; efficient use of the internal volume of the reactor; improved safety in case of the heat exchanger tube leaks; enabling the removal of residual heat during the time after removal of the protective plug before fuel discharge operations.

A stop seal for application of high temperature and high pressure is disclosed. A stop seal contains a first seal member and a second seal member, wherein the stop seal can prevent a fluid of high temperature and high pressure from leaking into an atmospheric space because, when the fluid of high temperature is introduced and the first seal member is moved toward a direction adjacent to a pump shaft, an opposite side of the second seal member is moved from a first position to a second position by the first seal member so as to block a gap between a pump side and a housing.

Provided is a reactor secondary side passive residual heat removal system, comprising: a containment vessel; a steam generator provided with a steam outlet and a water supply inlet; a water tank, the water tank being internally provided with a heat exchanger, the heat exchanger having a heat exchanger inlet and a heat exchanger outlet; and a steam driven pump provided with a steam port, a water inlet and a water outlet, wherein the steam generator, the water tank and the steam driven pump are arranged in the containment vessel, the heat exchanger inlet is in communication with the steam outlet of the steam generator by means of a first pipeline, the heat exchanger outlet is in communication with the water inlet of the steam driven pump by means of a second pipeline, the water outlet of the steam driven pump is in communication with the water supply inlet of the steam generator by means of a third pipeline, and the steam port of the steam driven pump is in communication with the first pipeline by means of a fourth pipeline. The present invention does not rely on an external driving force, thereby greatly reducing the failure probability of the system and improving the safety of the system.

Provided is a reactor secondary side passive residual heat removal system, comprising: a containment vessel; a steam generator provided with a steam outlet and a water supply inlet; a water tank, the water tank being internally provided with a heat exchanger, the heat exchanger having a heat exchanger inlet and a heat exchanger outlet; and a steam driven pump provided with a steam port, a water inlet and a water outlet, wherein the steam generator, the water tank and the steam driven pump are arranged in the containment vessel, the heat exchanger inlet is in communication with the steam outlet of the steam generator by means of a first pipeline, the heat exchanger outlet is in communication with the water inlet of the steam driven pump by means of a second pipeline, the water outlet of the steam driven pump is in communication with the water supply inlet of the steam generator by means of a third pipeline, and the steam port of the steam driven pump is in communication with the first pipeline by means of a fourth pipeline. The present invention does not rely on an external driving force, thereby greatly reducing the failure probability of the system and improving the safety of the system.

Arrangement for supporting U-bend tube sections in the high heat environment of steam generators using flat bars. The invention uses a combination of thicker and thinner flat bars to impart a serpentine path to the arc of the normally curvilinear U-tubes. The support system accommodates the dilation and contraction of coolant tubes and other elements caused by the extreme and varying conditions inside a steam generator, and which can cause gaps between coolant tubes and prior art tube support bars. Bars of alternating thickness provide alternating offsets to tensionally push and support each tube on multiple sides and in multiple locations, and this tension keeps the tubes in contact with at least some flat bars on multiple sides regardless of size and shape changes. Support arrangement includes a set of fan bars, each fan bar including thick and thin flat bars projecting up and out from a collector bar.

Arrangement for supporting U-bend tube sections in the high heat environment of steam generators using flat bars. The invention uses a combination of thicker and thinner flat bars to impart a serpentine path to the arc of the normally curvilinear U-tubes. The support system accommodates the dilation and contraction of coolant tubes and other elements caused by the extreme and varying conditions inside a steam generator, and which can cause gaps between coolant tubes and prior art tube support bars. Bars of alternating thickness provide alternating offsets to tensionally push and support each tube on multiple sides and in multiple locations, and this tension keeps the tubes in contact with at least some flat bars on multiple sides regardless of size and shape changes. Support arrangement includes a set of fan bars, each fan bar including thick and thin flat bars projecting up and out from a collector bar.

Combined cleanup and heat sink systems work with nuclear reactor coolant loops. Combined systems may join hotter and colder sections of the coolant loops in parallel with any steam generator or other extractor and provide optional heat removal between the same. Combined systems also remove impurities or debris from a fluid coolant without significant heat loss from the coolant. A cooler in the combined system may increase in capacity or be augmented in number to move between purifying cooling and major heat removal from the coolant, potentially as an emergency cooler. The cooler may be joined to the hotter and colder sections through valved flow paths depending on desired functionality. Sections of the coolant loops may be fully above the cooler, which may be above the reactor, to drive flow by gravity and enhance isolation of sections of the coolant loop.

Combined cleanup and heat sink systems work with nuclear reactor coolant loops. Combined systems may join hotter and colder sections of the coolant loops in parallel with any steam generator or other extractor and provide optional heat removal between the same. Combined systems also remove impurities or debris from a fluid coolant without significant heat loss from the coolant. A cooler in the combined system may increase in capacity or be augmented in number to move between purifying cooling and major heat removal from the coolant, potentially as an emergency cooler. The cooler may be joined to the hotter and colder sections through valved flow paths depending on desired functionality. Sections of the coolant loops may be fully above the cooler, which may be above the reactor, to drive flow by gravity and enhance isolation of sections of the coolant loop.