Induced nuclear reactions: processes – systems – and elements – Reactor protection or damage prevention – Auxiliary heat removal structure
Reexamination Certificate
1999-04-06
2001-05-29
Carone, Michael J. (Department: 3641)
Induced nuclear reactions: processes, systems, and elements
Reactor protection or damage prevention
Auxiliary heat removal structure
C376S243000
Reexamination Certificate
active
06240154
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of nuclear power plants. More particularly, the present invention relates to a self-actuating louver system that vents the CEDM cooling system of a nuclear reactor with ambient air when a forced stream of cooled air in the cooling system is discontinued.
BACKGROUND OF THE INVENTION
FIG. 1
illustrates a portion of nuclear reactor used in a nuclear power plant. The reactor head (
100
) communicates with the reactor vessel (not shown) in which the nuclear reaction takes place. A head lift rig (
106
) is mounted over the reactor head (
100
) and contains the control element drive mechanism (CEDM) (
105
).
The CEDM (
105
) is used to extend control rods (not shown) into the fissionable material in the reactor core in which the sustained nuclear reaction is occurring. The number of control rods used and the extent to which the control rods are extended into the reaction area controls the rate at which the nuclear reaction progresses. In the event of an emergency, an additional set of control rods can be rapidly extended into the core to halt the nuclear reaction entirely.
To shield the CEDM (
105
) from the heat of the reactor vessel, a heat shield of insulation (
101
) is provided as shown in FIG.
1
. However, this insulation (
101
) alone is insufficient to keep the optimal temperature in the head lift rig (
106
). Consequently, a cooling system is also provided to control the temperature in the head lift rig (
106
).
The cooling system includes, for example, a pair of pipes (
107
) through which cooled air is forced into the head lift rig (
106
). The cooled air flows through the head lift rig (
106
), around the CEDM (
105
) and into a chamber (
103
) between the insulation (
101
) and the main body of the head lift rig (
106
). Exhaust holes (
102
) are provided in this chamber (
103
) to allow the cooled air to complete its circulation.
While this cooling system is adequate to control the temperature in the head lift rig (
106
), obvious problems will arise if the cooling system malfunctions or must be turned off for any reason. Without the flow of air illustrated in
FIG. 1
, the temperature inside the head lift rig (
106
) will quickly rise if a nuclear reaction is ongoing, or will stay high even if no reaction is being sustained.
Consequently, there is a need in the art for a device and method of supplementing the cooling system for a CEDM in the head lift rig of a nuclear reactor.
SUMMARY OF THE INVENTION
It is an object of the present invention to meet the above-described needs and others. Specifically, it is an object of the present invention to provide a self-actuating system that assists in venting heat from the head lift rig any time the flow of cooled air through the cooling system is discontinued.
Additional objects, advantages and novel features of the invention will be set forth in the description which follows or may be learned by those skilled in the art through reading these materials or practicing the invention. The objects and advantages of the invention may be achieved through the means recited in the attached claims.
To achieve these stated and other objects, the present invention may be embodied and described as a cooling system for a head lift rig of a nuclear reactor. The system includes at least one pipe through which cooled air is forced into the head lift rig; and a self-actuating louver over a vent opening in either of the at least one pipe or the head lift rig. When the cooled air is circulating, the louver is held closed by pressure created by the circulating air. But, when the cooled air is not circulated, the louver automatically falls open to allow hot air from the head lift rig to exhaust and cooler ambient air to enter the head lift rig.
According to the present invention, there may be two self-actuating louvers, one of which is disposed over a vent opening in the at least one pipe and one of which is disposed over a vent opening in the head lift rig.
Alternatively, the cooling system of the present invention may include a flap valve louver regulating a vent opening in each pipe that provides cooled air to the head lift rig. Similar to the system described above, when the cooled air is circulating, the flap valve louver is held closed by pressure created by the circulating air, but when the cooled air is not circulated, the flap valve louver automatically falls open to allow hot air from the head lift rig to exhaust and cooler ambient air to enter the head lift rig.
This system may also include a louver over a vent opening in the head lift rig which operates like the flap valve louver, namely, when the cooled air is circulating, the louver is held closed by pressure created by the circulating air, but when the cooled air is not circulated, the louver automatically falls open to allow hot air from the head lift rig to exhaust and cooler ambient air to enter the head lift rig.
The present invention also encompasses the methods of cooling a CEDM corresponding to the systems described above. Such a method may include the steps of (1) forcing cooled air through at least one pipe into the head lift rig; and (2) regulating a vent opening in either or both of the at least one pipe or the head lift rig with a self-actuating louver such that, when the cooled air is circulating, the louver is held closed by pressure created by the circulating air, but when the cooled air is not circulated, the louver automatically falls open to allow hot air from the head lift rig to exhaust and cooler ambient air to enter the head lift rig.
Alternatively, the method of the present invention may include the steps of: (1) forcing cooled air through at least one pipe into the head lift rig; and (2) regulating a vent opening in each pipe with a flap valve louver such that, when the cooled air is circulating, the flap valve louver is held closed by pressure created by the circulating air, but when the cooled air is not circulated, the flap valve louver automatically falls open to allow hot air from the head lift rig to exhaust and cooler ambient air to enter the head lift rig.
This method may also include the additional step of regulating a vent opening in the head lift rig with a self-actuating louver, such that, when the cooled air is circulating, the louver is held closed by pressure created by the circulating air, but when the cooled air is not circulated, the louver automatically falls open to allow hot air from the head lift rig to exhaust and cooler ambient air to enter the head lift rig.
REFERENCES:
patent: 5742652 (1998-04-01), Hankinson et al.
patent: 5930321 (1999-07-01), Harkness et al.
Matteson Donn M.
Peck Daniel A.
Carone Michael J.
CE Nuclear Power LLC
Mun Kyonytack K.
Rader Fishman & Grauer
LandOfFree
Self-actuated louvers for venting a CEDM cooling system of a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Self-actuated louvers for venting a CEDM cooling system of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Self-actuated louvers for venting a CEDM cooling system of a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2534122