Nuclear reactor equipped with a flooding tank and a residual heat removal and emergency cooling system

Claim 2

A NUCLEAR REACTOR HAVING A PORTECTIVE ENCLOSURE SURROUNDING EQUIPMENT COMPRISING A REACTOR PRESSURE VESSEL, A COOLANT CIRCUIT CONNECTED TO SAID PRESSURE VESSEL FOR CONDUCTING COOLANT THROUGH THE SAME AND EXPOSED DIRECTTLY TO THE INSIDE OF SAID ENCLOSURE, A RESIDUAL HEAT REMOVAL AND EMERGENCY COOLING SYSTEM CONNECTED TO SAID COOLANT CIRCUIT FOR PROVIDING COOLING OF THE REACTOR CORE FOLLOWING A SHUT DOWN OF THE REACTOR OR A LOSS-OF-COOLANT ACCIDENT, AND A FLOODING TANK ARRANGED IN SAID PROTECTIVE ENCLOSURE AT AN ELEVATION ABOVE THE UPPER EDGE OF SAID REACTOR CORE, SAID FLOODING TANK BEING CONNECTED TO SAID CIRCUIT AND BEING CONFIGURED TO HOLD A QUANTITY OF LIQUID SUFFICIENT TO FLOOD SAID REACTOR CORE IN THE EVENT OF A LOSS OF COOLANT.

Claim 3

The nuclear reactor of claim 1, said flooding tank being located above said upper edge of said reactor core at a height sufficient to provide a pressure head for said liquid so that said liquid can flow unassisted to said reactor pressure vessel.

Claim 4

The nuclear reactor of claim 2 comprising a quick discharge valve communicating with said reactor pressure vessel.

Claim 5

The nuclear reactor of claim 3, said cooling circuit having a hot branch and a cold branch, said system comprising means for connecting said flooding tank to said cold branch to admit the flooding liquid thereto, said quick discharge valve being connected to said hot branch.

Claim 6

The nuclear reactor of claim 1, said system comprising a conduit for directing said liquid away from said flooding tank and toward said reactor pressure vessel and a pump connected in said conduit and developing a pumping pressure less than the design pressure of said protective enclosure.

Claim 7

The nuclear reactor of claim 5, said system comprising a check valve connected into said conduit.

Claim 8

The nuclear reactor of claim 1, said system comprising a conduit for directing said liquid away from said flooding tank toward said cooling circuit, and a check valve connected into said conduit.

Claim 9

The nuclear reactor of claim 7 comprising a fuel element storage pit, a sump located within said protective enclosure, and an arrangement communicating with said coolant circuit for removing residual heat, said arrangement comprising a cooling circulation circuit connected to said storage pit for circulating a liquid therethrough, a pump for driving the liquid through said circulation circuit, and means for connecting said pump to said sump.

Claim 10

The nuclear reactor of claim 7, said system comprising an arrangement for removing residual heat including a feed line, said feed line being equipped with a check valve and communicating with said coolant circuit intermediate said check valve of said conduit and said reactor pressure vessel.

Claim 11

The nuclear reactor of claim 9, said arrangement comprising a control member disposed outside of said protective enclosure for at least partially blocking said arrangement.

Claim 12

The nuclear reactor of claim 9 comprising a fuel element storage pit, and a sump located within said protective enclosure, said arrangement comprising a cooling circulation circuit connected to said storage pit for circulating a liquid therethrough, a pump for driving the liquid through said ciRculation circuit, and means for connecting said pump to said sump.

Claim 13

The nuclear reactor of claim 11, said arrangement comprising a control member disposed outside of said protective enclosure for blocking at least said feed line communicating with said coolant circuit.

Claim 14

The nuclear reactor of claim 11, comprising a line connected to said conduit ahead of said check valve in said conduit, and a safety injection pump connected to said lastmentioned line for pumping liquid from said tank into said reactor pressure vessel.

Claim 15

The nuclear reactor of claim 1, said flooding tank being configured as an annular ring adjacent said protective enclosure.

Claim 16

The nuclear reactor of claim 14, said annular ring having a shape corresponding to the contour of said protective enclosure.

Claim 17

The nuclear reactor of claim 15, said flooding tank being made of concrete coated with a layer of plastic.

Claim 18

The nuclear reactor of claim 16, said layer of plastic being reinforced with matting.

Claim 19

The nuclear reactor of claim 16, said layer of plastic being reinforced with fibers.

Claim 20

The nuclear reactor of claim 1, comprising a cylinder enclosing said reactor pressure vessel, said flooding tank being disposed above said cylinder.

Claim 21

The nuclear reactor of claim 19 comprising a sump located beneath said reactor pressure vessel, said cylinder having openings at the bottom thereof leading into said sump.

Claim 22

The nuclear reactor of claim 20 comprising respective valves closeable air-tight at said openings, said valves opening in response to pressure.

Claim 23

The nuclear reactor of claim 19 comprising a sump located beneath said reactor pressure vessel, said cylinder having siphons at the bottom thereof leading into said sump.

Claim 24

The nuclear reactor of claim 1, said system comprising a conduit for directing said liquid away from said flooding tank and toward said reactor pressure vessel, and cooling water enriched with boron disposed in said conduit.

Claim 25

The nuclear reactor of claim 23, at least one portion of said conduit having a lateral cross-section greater than the lateral cross-section of the remainder of said conduit.

Claim 26

A pressurized-water reactor installation having a protective enclosure completely enclosing equipment comprising a pressurized-water reactor pressure vessel containing a core, means forming a pressurized-water circulating circuit connected to said vessel, pressurized water contained by said circuit and vessel and when accidentally released therefrom forming vapor having vapor pressure, said enclosure having a containment strength greater than said vapor pressure and internally forming a space above said reactor and circuit, said vapor being contained in said space, means for holding a supply of emergency water sufficient to flood said vessel to at least above said core and with said emergency water positioned at an elevation above said core in said space and under the pressure in said space, and emergency means for connecting said emergency water to said circuit through a check valve positioned below said elevation, said check valve being normally closed by the pressure of said pressurized water and opening under the pressure of said emergency water at said check valve, when the pressure in said circuit becomes less than the pressure of said emergency water at said check valve.

Claim 27

A pressurized-water reactor installation having a protective enclosure completely enclosing equipment comprising a pressurized-water reactor pressure vessel containing a core, means forming a pressurized-water circulating circuit connected to said vessel, pressurized water contained by said circuit and vessel and when accidentally released therefrom forming vapor having vapor pressure, said enclosure having a containment strength greater than said vapor pressure and internally forming a space above said reactor and circuit, said vapor being contained in said space, means for holding a supply of emergency water sufficient to flood said vessel to at least above said core and with said emergency water positioned at an elevation above said core in said space and under the pressure in said space, and emergency means for connecting said emergency water to said circuit through a check valve positioned below said elevation, said check valve being normally closed by the pressure of said pressurized water and opening under the pressure of said emergency water at said check valve, when the pressure in said circuit becomes less than the pressure of said emergency water at said check valve.

Claim 28

The installation of claim 25 in which said circuit has a heat exchanger and a hot branch leading from said vessel to said heat exchanger and a cold branch leading from said heat exchanger to said vessel, and said check valve connects said emergency water with said cold branch, and said hot branch has means for quickly discharging said coolant to reduce the pressure of said coolant in said circuit.

Claim 29

The installation of claim 25 in which said emergency means includes means for pumping said emergency water to said check valve under a pressure less than said vapor pressure.

Claim 30

The installation of claim 25 in which said equipment further comprises means foR holding a supply of residualheat removal water coolant under the pressure in said space, and means for pumping the just-said supply of coolant under pump pressure into said circuit through a second check valve normally closed by the pressure of said pressurized water and opening when the pressure in said circuit is less than said pump pressure.