Abstract:
Safety valves accurately control closure and opening of fluid passage through the valve. Valves include a barrier that blocks the fluid until removal only by a high-energy projectile. Following removal and opening, the barrier or the projectile can flow through the valve, which remains open. Bullets, pneumatic pistons, shot, coilgun pellets and any other forceful projectile may impact and remove the barrier. The projectile is actuated with any type of chemical reaction, firing pin, spring release, accelerating circuit, ignition circuit. Catchers in the valve envelop or otherwise retain the projectile or barrier pieces and enter the fluid flow of the opened valve without blocking it. Disruptable barriers include strong but breakable glass plates, thin steel sheets, a rotatable door and other barriers that can withstand potentially over 10,000 psi of fluid pressure while closing the valve. Valves can use circuits to both monitor valve open/closed status and initiate firing the projectile.

Description:
BACKGROUND 
       [0001]    Several engineering systems, including nuclear power plants, use safety valves to ensure a flow path is opened in the case of malfunction, emergency, or needed operational relief. Such flow paths may ensure fail-safe status or operation of important safety systems and include valves that reliably open the flow paths in desired circumstances.  FIG. 1  is a cross-sectional schematic of a related-art explosive safety valve  10  in a closed configuration. As shown in  FIG. 1 , in a closed configuration, flow at an inlet  11  of valve  10  is blocked by a shear cap  40  between inlet  11  and outlet  12 . Shear cap  40  is attached to a casing of valve  10  at inlet  11  by shearing sections  45  that may readily or reliably break under known and desirable forces. Shearing sections  45  may still possess sufficient tensile and shear strength to keep valve  10  closed during normal operating conditions; for example, shearing sections  45  may have strength to withstand a normal operating pressure differential between inlet  11  and outlet  12 . Shear cap  40  may be further retained by a ring  41  or other keeping device passing through shear cap  40  to retain the same while allowing some movement or rotation. 
         [0002]    As shown in  FIG. 1 , an explosive cap  20  is paired with a moveable tension bolt  30  in a casing of valve  10 . Tension bolt  30  may be moveable and configured to be separated and driven under an explosive force of explosive cap  20  but not under spurious vibrations or impacts. Explosive cap  20  may be an assembly including several initiators or squibs that are activated through a circuit  25  or other connector. Tension bolt  30  is positioned to vertically drive down onto a moveable shearing piston  31 . Explosive cap  20  is positioned to explosively drive apart tension bolt  30  into shearing piston  31 , forcing shearing piston  31  downward with extreme force. When unactuated, shearing piston  31  may be upwardly maintained by low-force springs or other holders. 
         [0003]      FIG. 2  is a cross-sectional schematic of explosive safety valve  10  in an opened configuration. As seen in  FIG. 2 , exploded cap  20 ′ has separated and driven tension bolt  30 ′ into shearing piston  31 . In turn, shearing piston  31  has vertically sheared off shearing sections  45  ( FIG. 1 ), resulting in shearing cap  40 ′ becoming disconnected from inlet  11 . A pressure of fluid flowing from inlet  11  to now un-blocked outlet  12  pushed shearing cap &#39; 40  away from inlet  11 , and retaining ring  41  may cause shearing cap  40 ′ to rotate downward in such a situation. Shearing cap  40 ′ may contact a sensor  35  in a casing of valve  10 , which may signal to operators or automated systems that valve  10  has successfully opened. In this way, actuation of explosive cap  20 ′, potentially by an electric safety signal from connector  25 , has caused related art valve  10  to open and remain open. Co-owned “ESBWR Design Control Document, Tier 2,” Revision 10 of April, 2014, Chapter 5, describes helpful technological context and is incorporated by reference herein in its entirety. 
       SUMMARY 
       [0004]    Example embodiments include safety valves with reliable, discreet actuation modes and flexible designs to permit implementation in several different physical configurations. Example valves define a passageway to carry a fluid when the valve is opened. A barrier occludes the passageway in a closed configuration, preventing fluid from flowing through the closed valve. The barrier, however, is disruptable with a projectile that impacts the barrier when actuated. Upon impact, the barrier and/or the projectile can flow out of the passageway and valve, without blocking the same. 
         [0005]    Several different projectiles are useable in example embodiments, including bullets, captured striking rods, shaped pellets, etc. Projectiles may use electromagnetic forces, pneumatics, explosives, etc. to impact the barrier. For example, a gunpowder-fired bullet is useable as a projectile that can be fired with several different types of firing pins, accelerating circuits, ignition circuits, etc. potentially in resilient or redundant combinations. Example embodiment valves can use a catching apparatus to retain the projectile, barrier, or pieces of the same in the fluid flow, preventing dispersion of potentially multiple fragments into the fluid flow from the valve. The catching mechanism may dislodge into the fluid flow as a single envelope of all pieces, and such dislodging may be detected by sensors to indicate valve opening. 
         [0006]    Similarly, several different types of barriers can be paired with a projectile to ensure reliable and complete valve opening. For example, a shatterable glass plate, a flexible sheet with a breakable cap, a rotatable door with a breakable cap, etc. Such barriers can withstand several thousands of pounds of pressure, high temperatures, mechanical damage, radiation, etc. and remain blocking and thus closing the valve. Through an intentionally frangible portion or material, the barrier can break apart into the flow passageway, opening the same. The pieces can then independently flow out of the valve without blocking, while assuring valve opening. Circuits through barriers and other valve components can easily determine valve status given the disruption or destruction of various parts upon projectile firing and barrier removal. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0007]    Example embodiments will become more apparent by describing, in detail, the attached drawings, wherein like elements are represented by like reference numerals, which are given by way of illustration only and thus do not limit the terms which they depict. 
           [0008]      FIG. 1  is a cross-sectional schematic of a related art safety valve in an unfired position. 
           [0009]      FIG. 2  is a cross-sectional schematic of the related art safety valve in a fired position. 
           [0010]      FIG. 3  is a cross-sectional schematic of an example embodiment projectile impact safety valve. 
           [0011]      FIG. 4  is a cross-sectional schematic of another example embodiment projectile impact safety valve. 
           [0012]      FIG. 5  is a cross-sectional schematic of another example embodiment projectile impact safety valve. 
           [0013]      FIG. 6  is a cross-sectional schematic of another example embodiment projectile impact safety valve. 
           [0014]      FIG. 7  is a profile view of a projectile and actuator system useable with example embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Because this is a patent document, general broad rules of construction should be applied when reading and understanding it. Everything described and shown in this document is an example of subject matter falling within the scope of the appended claims. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use example embodiments or methods. Several different embodiments not specifically disclosed herein fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only example embodiments set forth herein. 
         [0016]    It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0017]    It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” or “fixed” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange routes between two devices, including intermediary devices, networks, etc., connected wirelessly or not. 
         [0018]    As used herein, the singular forms “a”, “an” and “the” are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise with words like “only,” “single,” and/or “one.” It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, steps, operations, elements, ideas, and/or components, but do not themselves preclude the presence or addition of one or more other features, steps, operations, elements, components, ideas, and/or groups thereof. 
         [0019]    It should also be noted that the structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from the single operations described below. It should be presumed that any embodiment having features and functionality described below, in any workable combination, falls within the scope of example embodiments. 
         [0020]    The Inventors have newly recognized that existing safety valves are relatively large, with several moving parts among an explosive cap, tension bolt, and shear cap. It is difficult to adapt larger valves across several differently-sized injection points in different plant and engineering system designs without significantly varying functionality and matching different explosive caps to each different shearing cap size. The Inventors have further recognized that existing safety valves, with dividing tension bolts, several initiating squibs, and large explosive caps to drive the bolts, are likely to become damaged at initiation, potentially moving a shearing cap into the flow path to block the same or damaging actuation sensors. The Inventors have additionally recognized that reliable chemical components for explosive caps, providing a precise amount of energy for reliable actuation without degradation over time, are not readily known or easily acquired. Example embodiments described below address these and other problems recognized by the Inventors with unique solutions enabled by example embodiments. 
         [0021]    The present invention is safety valves with highly-reliable, discreetly-disruptable flow barriers that control an open or closed status of the valve. In contrast to the present invention, the few example embodiments and example methods discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention. 
         [0022]      FIG. 3  is an illustration of an example embodiment projectile impact safety valve  100 . Although not shown in  FIG. 3 , example safety valve  100  is useable between any flow areas or conduits, including between coolant injection sources and nuclear reactors, in place of or in combination with related art valves  10  ( FIGS. 1-2 ). As seen in  FIG. 3 , a body or conduit  110  directs or carries fluid to a desired destination. Conduit  110  is blocked by barrier  150 , which prevents such flow through conduit  110  while intact. Barrier  150  is largely impermeable to the fluid and configured to prevent fluid flow through conduit  110  at any range of pressure differentials across barrier  150 . For example, P1 to the right of barrier  150  in  FIG. 3  could be nearly equal or higher, such as several megapascals or over ten-thousand psi higher, than P2 on the left, and barrier  150  remains intact, preventing fluid flow through conduit  110 . As a specific example in a nuclear reactor, P1 may be over 1100 psia in order to ensure injection into a reactor system operating at P2 under 1100 psia. Barrier  150  when intact prevents flows in conduit  110  under such conditions, even when subject to high temperatures, corrosive fluids, mechanical vibrations and shocks, and/or radiation encountered in an operating nuclear reactor environment. 
         [0023]    Barrier  150  is disruptable only under impact from projectile  140 , ensuring discreet and intentional failure of barrier  150  and commencement of flow through conduit  110 . Projectile  140  may be a bullet, pellet, shell, striking rod, or other material that is capable of being forcefully projected at, and disabling, barrier  150 . For example, projectile  140  may be a ballistic element made of solid, higher density material and propelled through ignition of gunpowder or other explosive about the projectile in chamber  114  off conduit  110 , such as a .22 round. Or, for example, projectile  140  may be a metallic rod or pellet accelerated under electromagnetic or pneumatic forces from within chamber  114 . Upon impact with barrier  150 , projectile  140  ruptures or otherwise mechanically changes barrier  150  such that fluid will flow through conduit  110  without being blocked by barrier  150 . 
         [0024]    Projectile  140  may be positioned anywhere to ensure accurate and disruptive contact with barrier  150  when actuated. As shown in  FIG. 3 , projectile  140  may be positioned in chamber  114  directed at barrier  150  on what is expected to be an evacuated or lower-pressure side of barrier  150 . In such an example, projectile  140  may extend through relatively empty and/or less dense space of conduit  110 , more easily ensuring accurate impact with barrier  150 . Or, for example, projectile  140  may be positioned in a central part of channel  110 , in barrier  150 , or on either side of barrier  150  where it can be accelerated under force to contact and disrupt barrier  150 . 
         [0025]    Because chamber  114  and projectile  140  may be placed in several different positions and in any number while still being able to strike barrier  150 , example embodiment valve  100  may be more resistant to damage or failure, particularly in mechanical or thermal challenges likely encountered exactly when a safety valve must actuate. For example, redundant, top- and bottom located chambers  114  and projectiles  140  may ensure that any damage done to a top of valve  100 , such as by a falling piece of equipment in a seismic event, does not affect functionality of example embodiment valve  100 , which can still actuate with a bottom projectile  140 . 
         [0026]    Projectile  140  may be paired with an actuator  141  including a starter or other force-generating device as well as sensors to determine actuation of projectile  140  and thus opening of example embodiment safety valve  100  by disruption of barrier  150 . For example, actuator  141  may include an electric circuit for propelling projectile  140 . Such an electric circuit in actuator  141  may, for example, ignite an explosive like gunpowder, cause two reagents to be mixed in an explosive or expanding reaction, or create a magnetic field in a railgun or coilgun-type configuration, to propel projectile  140 . With a sensor for receiving signals from a controller or safety system, upon receipt of an emergency or actuation signal, or loss of power in a fail-open configuration, actuator  141  may drive projectile  140  to impact barrier  150 , opening conduit  110 . Actuator  141  may further generate signals to confirm discharge, or non-discharge, of projectile  140  via connection to a control room or operator. 
         [0027]    Example embodiment projectile impact safety valve  100  may further include a catcher  160  to retain and/or collect barrier  150  or remnants thereof. For example, catcher  160  may be a fine metal mesh that retains fragments of barrier  150  drawn downstream through conduit  110  following destruction of barrier  150 . Or, for example, catcher  160  may be a balloon, magnet, or adhesive that envelops, traps, or joins to barrier  150  and pieces thereof as they flow downstream after being struck by projectile  140 . Catcher  160  may itself then release into conduit  110  or at an exit of valve  100 , containing all pieces together in the flow. Catcher  160  may always be present and static or may include an actuator  161  that releases catcher  160  coincident with actuation of projectile  140 . Actuator  161  may further include a sensor for receiving signals to deploy catcher  160  and/or to report the presence or actuation of catcher  160 . 
         [0028]    As shown in  FIG. 3 , barrier  150  may be paired with a sensor  151 , and it is also possible to include a flow sensor  111  along conduit  110 . Barrier sensor  151  may confirm presence or intact status of barrier  150 , and conduit sensor  111  may be a flowmeter to other flow detection device. In this way, sensors  151  and  111  may further confirm open or closed status of example embodiment valve  100  through detection of presence of barrier  150  or fluid flow through conduit  110 . Signals from sensors  111  and/or  151  may be reported to a control room or valve operator, for example, indicating valve open or closed status, or, more specifically, barrier  150  status. 
         [0029]    Barrier  150 , projectile  140 , projectile actuator  141 , and catcher  160  may be embodied in several different ways in example embodiments. Without need for a heavy tension bolt and/or large explosive cap to achieve releasing sheer, and instead using a relatively smaller and/or more flexible projectile, example embodiment valve  100  may be sized and shaped with barrier  150  and projectile  140  in a variety of different locations and engineering situations and easily adapted for different space requirements. Regardless of exact implementation, projectile  140  and barrier  150  provide a highly-controllable and reliable structural pairing that controls flow through conduit  110 . The examples below illustrate specific types of barriers  150 , catcher  160 , and/or projectile  140  with actuator  141 , it being understood that these examples are interchangeable and nonexclusive. 
       Glass Barrier 
       [0030]      FIG. 4  is an illustration of an example embodiment projectile impact safety valve  200  using a vitreous barrier  250 . For example, barrier  250  may be a high-strength glass or similar material of a thickness sufficient to withstand a static fluid pressure differential across barrier  250 . For a circular channel  210  with an approximately 12-inch diameter, barrier  250  being cylindrical and approximately 2.5 inches thick may be sufficient to withstand a several-thousand psi pressure differential with a safety factor of 4 for most types of common silicate glass. Of course, other thicknesses and types of glass may be chosen based on varying conduit  210  sizing and shape as well as known pressure differentials and desired safety factors. 
         [0031]    Glass barrier  250  will shatter, or significantly degrade in strength, however, under impact from a projectile. The projectile is of sufficient speed and mass to disrupt glass barrier  250 , despite glass barrier  250  potentially withstanding large pressure differentials in conduit  210  with a safety factor of 3 or higher. A projectile may create over ten thousand pounds of pressure locally about an impact point, uniquely cracking and/or shattering otherwise strong glass, causing failure of barrier  250 . For example, a bullet such as a .22 long rifle round fully impacting a relatively inelastic 2.5-inch glass barrier  250  at around 1600 feet per second will cause failure by shattering—even in glass barrier  250  holding back a large (thousands of psi) pressure differential across barrier  250  due to fluid pressure. Or for example, using a stronger or less shatterable glass, like a borosilicate or laminated glass of 1.2 inch thickness, the projectile may still significantly crack and weaken glass barrier  250  upon impact, such that a large fluid pressure differential will then be sufficient to break up barrier  250 . 
         [0032]    In the example of  FIG. 4 , glass barrier  250  is rigidly held in place in conduit  210  by gasketted retainers  215 . For example, retainers  215  may be a stainless steel lip, rim, or edge extending around glass barrier  250  with a rubber or other elastic gasket intervening to prevent leakage. If retainers  215  and/or conduit  210  is narrower on a higher-pressure side of barrier  250 , such that barrier has less surface area exposed to a higher pressure fluid, a higher safety factor may be achieved, while still providing a large surface area for a projectile to impact and cause failure in glass barrier  250 . A projectile may be positioned or aimed toward such a larger face of glass barrier  250 , as seen in  FIG. 4 , where a chamber  214  may house a projectile and associated actuator. 
       Mesh Catcher 
       [0033]    Example embodiment safety valve  200  may further include a mesh catcher  260  fitted about an end of conduit  210 . Or mesh catcher  260  may be fitted much farther downstream, such as at an end of a pipe which valve  200  controls. Mesh catcher  260  may be a fine metallic mesh structure surrounding an exit of conduit  210 , such as a 0.5 mm hole-size stainless steel mesh. Mesh catcher  260  may also be a non-metallic material, containing a metallic or wiring liner to conduct electricity. Mesh catcher  260  may allow fluid, such as fluid in the space being injected into, to pass with minimal interference, but mesh catcher  260  may retain shards or pieces of glass barrier  250  following destruction of the same by a projectile to open valve  200 . Catcher  260  may further retain a bullet or pellet projectile used to rupture barrier  250 . In this way, pieces of glass barrier  250 , other barrier pieces, and/or a bullet or pellet may not enter the system being injected into or interfere with other components in the system. 
         [0034]    Mesh catcher  260  may include an elastic band  262  wound about an end of catcher  260  to keep an end of catcher  260  closed. Particular in the instance that catcher  260  dislodges from conduit  210  or another injection site pipe, elastic band  262  may seal an end of catcher  260 , keeping all glass pieces from barrier  250  as destroyed therein. Elastic band  262  may be of a strength so as to reliably secure mesh catch  260  until desired activation of safety valve  200 , such that catcher  260  is removed only with opening of valve  200  and only after catching solid debris from such opening. 
         [0035]    Mesh catcher  260  may further be attached to a sensor  261 , such as copper or other conductive wiring, that indicates presence of catcher  260  or status of valve  200  through electrical signals. For example, sensor  261  may maintain a low-level current through a metallic mesh catcher  260 , indicating that mesh catcher  260  is present and thus valve  200  is not open or discharging. Upon rupture of barrier  250  and removal of mesh catcher  260  due to fluid injection and receipt of barrier fragments, the low-level current may be broken. In this way, an operator may determine that example embodiment valve  200  is open and carrying fluid because mesh catcher  260  has been removed by such opening. An operator may also determine if mesh catcher  260  has detached spuriously or failed due to a lack of the low-level current detected by sensor  261 . In this way, an operator may thus know whether valve  200  has malfunctioned and whether to look for catcher  260  detached from the same. 
       Ductile Barrier 
       [0036]      FIG. 5  is an illustration of an example embodiment projectile impact safety valve  300  using a flexible metallic barrier  350 . As seen in  FIG. 3 , barrier  350  may include two or more leafs or segments forming a complete or partial conical barrier  350 . The segments may be flexible, such as a ductile metal like thinly-milled stainless steel sheets. The segments are joined by a cap  355  that holds the segments together at an end of the conical shape, thus forming barrier  350 . Cap  355  can be any structure that will hold conical barrier  350  together. For example, cap  355  may be a carbon steel bar or prismatic tip joined to barrier  350 . In the instance that both cap  355  and barrier  350  are metallic, cap  355  and barrier  350  may be joined by welds  356  that easily shear but are otherwise very stress resistant. 
         [0037]    One or more projectiles  340  are positioned about cap  355  and configured to impact the same upon actuation. For example, projectile  340  may be a pneumatic piston or bullet aimed at cap  355  from edges of conduit  310 . Upon actuation projectiles  340  impact and destroy or separate cap  355  from barrier  350 . For example, if cap  355  is a carbon steel cap welded to stainless steel conical barrier  350 , projectile  340  may strike cap  355  with sufficient force to break or shear off welds  356 . Cap  355  may be sufficiently long such that several projectiles  340  can be positioned or aimed at different length areas from different angular positions about cap  355 . Such redundant and varied placing of projectiles  340 , while still permitting impact and disruption of barrier  350  in example embodiment valve  350 , may improve robustness and reduce likelihood of failure in the event any one projectile becomes damaged or disabled. 
         [0038]    When cap  355  is removed, barrier  350  is sufficiently disrupted such that fluid can flow through barrier  350  in the direction shown in  FIG. 5 . Leafs or segments of barrier  350  are sufficiently flexible or ductile that, upon being unjoined from cap  355  and exposed to fluid flow through the space left by cap  355 , barrier  350  will bend or “peel” back toward interior edges of conduit  310  under a pressure differential, where P1 is greater than P2. Once bent or moved toward conduit  310 , barrier  350  will remain relocated, opening example embodiment valve  300 . However, while cap  355  is in place, barrier  350  has sufficient strength to remain unbent and fully resist pressure differential between P2 and P1, potentially to several safety factors. For example, barrier  350  may be fabricated out of two thin stainless steel segments that join to cap  355  by welds  356 , which may present sufficient strength while intact not to deform. 
         [0039]    Barrier  350  in example embodiment valve  300  may be sized and positioned based on expected pressure differential and sizing of conduit  310 . Similarly, projectiles  340  may be of any number and in any position to ensure removal of cap  355  upon actuation, achieving reliable disruption and failure of barrier  350  only upon impact. Sensors and catching structures, although not shown, may equally be used with example embodiment valve  300 . For example, an electromagnet catcher may be installed downstream in conduit  310  to attach and retain any bullet and cap  355  made of ferrous materials. 
       Hinged Barrier 
       [0040]      FIG. 6  is an illustration of an example embodiment projectile impact safety valve  400  using a hinged door barrier  450 . As seen in  FIG. 3 , door barrier  450  may be attached to a conduit  410  in valve  400  via a hinge  457 . When closed, door barrier  450  may seat against a gasket  415  and be held in place by cap  455  secured to an inner surface of conduit  410 . For example, cap  455  and conduit  410  may be metallic, and welds  456  may join the two. 
         [0041]    Similar to other embodiments, projectile  440  may be positioned to impact cap  455  on barrier  450 . For instance, projectile  440  may be a bullet that strikes about an arm of cap  455 , breaking welds  456 . Projectile  440  may impact welds  456  with greater force through a larger torque arm provided by a shape of cap  455 . The greater force of projectile  440  and better leverage offered by cap  455  may be sufficient to reliably break welds  456 , whereas any pressure gradient on either side of barrier  450  may be of insufficient force and/or leverage to break welds  456  by a safety factor of three or more. 
         [0042]    Once welds  456  are broken by projectile  440  having struck cap  455 , door barrier  450  may swing open about hinge  457  under force from a fluid behind door  450 . Cap  455  may remain attached to door barrier  450 , breaking only about welds  456  to conduit  410 . In this way, fewer fragments or shards may be created by the removal of barrier  450  in example embodiment safety valve  400 . 
       Electronic Actuation Systems 
       [0043]      FIG. 7  is an illustration of an example embodiment projectile  540  and actuator(s)  541 . An electric circuit from actuator  541  drives projectile  540  toward a barrier, such as disruptable barrier  150  ( FIG. 3 ) to open a safety valve. In  FIG. 7 , a bullet  540  is used as a projectile. For example, bullet  540  may be a rimfire-style .22 (long or short) round bullet. Bullet  540  includes gunpowder  545  or a similar variant explosive in a lower portion that fires and drives bullet  540 . Such explosives may be ignited through striking a rim portion of bullet  540 , through electrical current, or through thermal ignition. A .22 caliber round with gunpowder may be particularly advantageous in a nuclear reactor environment, because .22 caliber ballistics are well-developed and known to be reliable, and high-quality .22 rounds are available from several providers. Moreover, gunpowder is a reliable explosive that remains potent over long periods of time and is fairly resistant to radioactive activation and deterioration. 
         [0044]    As shown in  FIG. 7 , bullet  540  can be driven by multiple actuators  541  using several different ignition or propellant systems. For example, up to four different contact or ignition points  510  may be spaced about the lower rim of bullet  540 . Although not visible given the side profile of  FIG. 7 , each actuator  541  and associated ignition or propelling structure may be spaced angularly at 90-degree intervals or more. In this way, bullet  540  can be propelled through several different systems, providing redundancy and diversity in projectile mode and avoiding the potential for any single failure to prevent firing. Although several different projectile methods are shown in use with bullet  540 , it is understood that only one, or a different combination, as well as other non-illustrated, modes of firing a projectile are useable in example embodiments. 
         [0045]    For example, in  FIG. 7 , a bare wire or other circuit may connect to a contact point  510  about a base of bullet  540 . When actuator  541  provides a current or signal, a circuit may be completed through a casing of bullet  540 , igniting gunpowder  545  and discharging bullet  540 . Or, for example, an induction-type coil  550  may be wrapped above bottom rim of bullet  540 . When actuator  541  passes a current though coil  550 , gunpowder  545  may be thermally ignited by the resulting induction. Moreover, if bullet  540  is ferromagnetic, a magnetic field generated by current in coil  550  may further propel bullet  540  (or any ferromagnetic projectile) in a similar manner. 
         [0046]    As further examples, solenoid-driven contact pin  520  may be used to fire bullet  540  by striking a bottom rim of bullet  540  with a firing pin. Contact pins  520  may provide additional options of fail-safe and fail-as-is implementations. For example, a spring  521  may drive firing pin  520  either toward or away from bullet  540  and must be opposed by a solenoid activated by actuator  541  in order to move firing pin  520 . This can be used to achieve a fail-as-is effect as shown in lower solenoid-driven firing pin  520  in  FIG. 7 , where spring  521  urges pin away from bullet  540 . In order to achieve firing of lower pin  520 , actuator  541  must provide a current or signal to activate the solenoid and counter spring  521 , such that lower pin  520  will cause ignition through contact only when a signal or firing current is received, but not in a loss-of-power or other failure scenario, where spring  521  will keep the lower pin  520  from firing bullet  540 . 
         [0047]    Or this can be used to achieve a fail-safe effect as shown in upper solenoid-driven firing pin  520  in  FIG. 7 , where spring  521  urges pin toward bullet  540 . To prevent contact and thus firing by upper pin  520 , actuator  541  must continuously provide a current or signal to activate the solenoid and counter spring  521 , pulling upper pin  520  away from bullet  540 . Upper pin  520  will cause ignition through contact whenever that signal or firing current is lost, such as in a loss-of-power or other failure scenario, because spring  521  will drive the upper pin  520  to contact the lower rim and fire bullet  540 . In this way, example embodiment safety valves may be ensured to open in loss of power or other failure scenarios, which may be desirable if a particular safety system for such loss-of-power transients requires an open valve. 
         [0048]    Each actuator  541  may be individually connected to an operator or control room for example for individual use and actuation. Similarly, all actuators  541  may be on a combined circuit and thus configured to fire simultaneously without individual use. Actuators  541  may receive and condition signals from operators to properly initiate and fire bullet  540  by generating appropriate amounts of current. Similarly actuators  541  may be connected to safety systems, such as nuclear plant automated safety systems, and receive ignition signals from such systems in order to automatically and reliably open valves necessary for such safety systems. Further, actuators  541  may include sensors or generate signals that indicate a status of bullet  540  and/or a valce containing the same. For example, actuators  541  connected to an induction coil  550  may be able to determine presence or absence of bullet  540  through resistance in coil  550  and report the same to an operator or as a valve status. Similarly, actuators  541  controlling solenoid-driven ignition pins  520  may detect a firing or pin status based on electrical properties and report the same. 
         [0049]    Although actuators have been described in connection with a conventional .22 round bullet using gunpowder as a propellant, it is understood that other projectiles and driving forces can be used in combination with example embodiments, including magnetic- or induction-based coilgun or railgun configurations, use of other chemically expanding propellants, pneumatic propulsion, etc. Because example actuators and projectiles may be reconfigured in a number of different ways, example embodiment valves are useable with a wide variety of systems regardless of shape, size, failure risks, etc. 
         [0050]    Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied and substituted through routine experimentation while still falling within the scope of the following claims. For example, a variety of different physical valve configurations have been shown with different physical barriers that are removed for valve operation; however, other types of barriers are compatible with example embodiments and methods simply through proper dimensioning and placement in connection with a projectile—and fall within the scope of the claims. Such variations are not to be regarded as departure from the scope of these claims.