WO2013165469A2

WO2013165469A2 - Method and apparatus for fusion capsule filling and plugging

Info

Publication number: WO2013165469A2
Application number: PCT/US2012/070586
Authority: WO
Inventors: Robert BURDINE
Original assignee: Lawrence Livermore National Security, Llc
Priority date: 2012-01-03
Filing date: 2012-12-19
Publication date: 2013-11-07
Also published as: WO2013165469A3

Abstract

Apparatus for filling capsules having openings therein is disclosed. The apparatus includes an enclosure, typically a tube or pipe, which is divided into zones by valves. Each zone is coupled to appropriate process equipment such as a vacuum pump or reservoir of material to treat the capsules. As the capsules progress through the enclosure they can be filled with appropriate material and the openings sealed.

Description

METHOD AND APPARATUS FOR FUSION

CAPSULE FILLING AND PLUGGING

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[000 1 The United States .Government 3ms rights in this invention pursuant to Contract No. DE-AC52-07NA27344 between the United States Department of Energy and Lawrence Livermore National Security, LLC, for the operation of Lawrence Livermore National Laboratory.

REFERENCE TO RELATED APPLICATION

[0002] This application claims priority from U.S. Provisional Patent Application entitled: "Method and Apparatus for Fusion Capsule Fill and Plug ". filed January 03, 2012, as Serial ^'Number 61 /582.678, the^'contents of which are incorporated by reference.

BACKGROUND OF THE INVENTION

[0003] This invention relates to fuel for^'ineriia . confinement fusion power plants, and in particular to the design and manufacture of a targets which include a fuel capsule, for use in such ^'fusion power plants.

[0004] The National Ignition Facility (NIP) is a laser-based inertia! confinement fusion research machine located at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. MF uses lasers to heat and compress a capsule of deuterium and tritium (DT) foe! capsule held in a hohlraum to the temperatures and pressures to cause a nuclear fusion reaction.

[0005] Inertia! confinement fusion power plants using the technology now being developed at MF have been proposed. The equipment, systems and support, necessary for the deployment of such a fusion power plant are now being investigated and designed at LLNL. In the indirect drive approach to inertia! confinement fusion (often ' ^'CF' herein), a spherics! capsule on the order of 4 mm in diameter containing the DT fuel is held inside a hohlraum; the two together being referred to herein as a "target " The targets are injected into a fusion engine chamber and, as they arrive at the center of the chamber, are fired upon by a bank of lasers. in NIF a bank of 192 lasers fires upon a target held at the center of the chamber by & fixed arm. The bohiraum absorbs and re-radiates the energy of the laser beams striking the Inside of the hohtraam as x-rays onto the fuel capsule. This causes the outer, surface of the fuel capsule to ablate, compressing and heating the DT fuel to cause a fission reaction,

[0006] As presently contemplated, a megawatt size inertia! confinement fusion power plant will rely upon fusion reactions from on the order of 10 to 1.5 targets per second. Thus, inertia! confinement fusion target designers must consider many engineering .requirements in addition to the physics requirements for a successful target implosion. Among these considerations i a need to manufacture large numbers of fuel capsules, e.g. more than 300 million capsules per year per plant. The hofelraam with its fiiel capsule must survive injection into the hostile environment of the fusion chamber, wh le resisting high acceleration forces and extreme environmental conditions. Of particular Importance to this invention, the fuel capsules for each target must have a precise configuration, be easily and relatively quickly filled with the DT fuel, yet be able to be manufactured at low cost in high volumes.

[0007] The NIF hohfcaum i a generally cylindrical cavity whose walls emit radian energy towards the interior. A typical prior art NIF bohiraum and fuel ^'capsule, is shown in Figure 6. in that illustration hohlraurn 100 Is shown held in: place by the arms 101. Laser beam entrance openings 102 in each end of the cylinder allow laser beams 103 to strike the interior wall of the hohlraum 100 where the fuel capsule 104 is located. To date the fuel capsules used at NIF have, been "custom" made in small batches suitable for a scientific research operation, as opposed to the lower cost, higher volume necessary for commercial applications. The NIF fuel capsule is described in Laser and Particle Beams, Volume .17, Issue 02, April 1 99, pp. 217-224, and "Plastic ablator ignition capsule desig for the National Ignition Facility," Daniel S. Clary et al, The Sixth International Conference on inertia! Fusion Sciences and Applications, Journal of Physics; Conference Series 244 (2010).

SUMMARY OF ΊΉΕ INVENTION

[0008] The invention .relates to apparatus that can accept an empty fusion capsule, fill the capsule, plug the -capsule's fill hole and release the capsule to production. The capsule may be filed with a gas, fluid or solid, and the fill may be made at a lowered or elevated pressure. The invention enables a capsule end product having a filled, pressurized or partially evacuated, and plugged capsule.

[0009] Embodiments of the invention provide for the rilling and plugging of a capsule with a plurality of materials under different conditions. Embodiments of the invention provide a .means of containment of capsules, flow of capsules, isolation of capsules into process areas and release of capsules. In particular embodiments, the invention includes a means to propel a capsule into the next process area. Valves or other suitable apparatus control the flow of capsules and isolate the various processes from each other.

[0010] In one embodiment apparatus for filling capsules having openings therein includes an enclosure extending from first end to an opposite end- The enclosure, typically tube or pip shaped, ca be divided into zones by valves along its length. Capsules enter the enclosure through a load-lock type apparatus. Using gravity, pressure, or other means the capsules are moved from zone to zone, with, appropriate processing performed in each zone. For example, once in a zone, valves at each end -of the zone can he closed, and a vacuum pump used to withdraw ambient atmosphere from that zone. Then the desired fill material is introduced into the zone to fill the- capsules. Then valves can then be appropriately opened and the capsules moved to the- next zone for further processing, e. g. application o f a sealant to close fill holes in the capsules.

[001 i] The apparatus has particular utility in the manufacture of targets for a fusion power plant, in this application a method for introducing isotopes of hydrogen into capsules, each having a till hole in the wall thereof, includes steps of opening a first valve to allow a batch of capsules to flow into a first: portion of an enclosure, the first portion being separated .from the remainder of the enclosure by a second valve and then introducing the isotopes of hydrogen into the first portion of the enclosure and thereby into the batch of capsules. Next the second valve is opened to allow the batch of capsules to flow into a second portion of the enclosure., the second portion of the enclosure being separated from remaining portions of the enclosure by a third valve. Then a sealant is introduced into the second portion of the enclosure to seal the fill holes in the batch of capsules. Finally the third valve is opened to allow the batch of capsules to flow out. of the second portion of the enclosure.

BRIEF DESCRIPTION OF THE DRA WINGS

[0012] Figure 1 is a cross~sectionaf view of a capsule; [001.3] Figure 2 is a cross-sectional vi ew of a tube with chambers defined by valves;

[0014] Figure 3 is a cross-sectional view of a tube with processing elements;

[0015] Figure 4 is a cross-sectional view of the capsule showing the til! hole plugged;

[001 ] Figure 5 illustrates a process for plugging the fill hole; and

[0017] Figure 6 illustrates. a prior art boh!raum and capsule,

DETAILED DESCRIPTION OF THE INVENTION

{0018] This invention relates to capsule filling, and to apparatus that can accept an empty capsule, fill the capsule, plug the capsule's fill access opening and release the capsule. The capsule may be filled with a gas. fluid or solid, and the till may he made at lowered or elevated pressure to result m an end product of a filled, pressurized or partially evacuated, and plugged capsule. The capsules can have any desired use. for example, a paintbait a container for a, pharmaceutical, a bullet, etc.

[001 ] A particular use of the technology described here is the production of targets for a fusion 1CF power plant. As mentioned above, a fusion chamber as envisioned for about a 1 megawatt size power plant is expected to require the deliver}' of targets at a high rate, on the order of more than 1 million per day. The target contains a capsule that acts as the implosion device, being .filed with a composition of deuterium and tritium hydrogen isotopes. In the present implementation the capsule for the fusion ICF power plant is filled with the gaseous DT hydrogen isotopes at an elevated pressure, and the fill hole is then plugged to prevent the escape of the elevated pressure gas. The capsule is then cooled to .cryogenic temperature to solidify the gases on the inside wail of the capsule. The hole plug must be suitable to contain the gas at both ambient and cryogenic temperatures.

[002.0] In the process described here, the capsule is filed and plugged in a continuous mass production manner by immersion. The process is particularly useful for filling fusion capsules with deuterium and tritium, and then plugging them. The process is also useful for filling paintballs, pharmaceuticals, rounds, pills, or other materials requiring filling and plugging. It can also be used for filling pressure bottles, e.g. with C02.

[0021] The invention pertains to the filling of capsules of varying composition, and the plugging of such capsules. The invention also provides techniques for a mass production continuous process of immersion filling and plugging of capsules or containers of ar bitrary shape and size: The process is particularly suited to filling rigid capsules or containers with relatively small fill, holes that require plugging with minimal or no apparent disturbance to the capsule or container shell. The invention enables a continuous mass production process in which the capsule is .filled and plugged, as well as providing redundancy and configuration of a parallel production means thai maintains production duri ng faults or failures of particular production apparatus.

[ 0022 ] Figure I illustrates capsule for use in an ICF power plant. On the left side of Figure I is an exterior view of a capsule 1 with a Oil hole 2. Such a capsule typically comprises a plastic or carbon based shell, which ma have inside it, on the interior surface of the wall, a layer of aerogel, nanoporous foam, or other material, for example as described in commonly assigned U.S. patent application entitled: "Porous Scaffolds For Hydrogen Fuel ¼ Inertia! Confinement Fusion Capsules " serial numbe 1 3/670,288, and dated November 6, 2012, the contents of which are incorporated b reference herein. On the right side of Figure 1 is a cross-seotiana! view showing the capsule 1. hole 2, wall 3, and fill volume 4 (into which the fill material will ^'be placed).

[0023] Figure 2 is a cross-sectional view of a tube 5 with chambers defined by valves 6 that can he opened or closed -allowing, entrance* isolation and -exit of fill material for capsules. Entrance opening 7 allows, the initial entry of capsules 1 , while exit opening 8 allows the release of capsules I, The process will be described in more detail with respect Co F gur 3. As used herein the terms- "tube" and "valve" are used in reference to their respective generalized functions. The term "tube", for example, is used as a reference to a container of arbitrary shape and size. "Valve" is used to refer to an isolation device or .means that facilitates the isolation, division or transfer through of the product. As explained herein, this Invention is particularly suitable for receiving product in the form of empty capsules or containers provided with a t ll hole or holes, immersion filing the capsules and immersion plugging the hole or holes.

[0024] Figure 3 is a cross-sectional view of tube 5 through which the capsules flow, together with processing equipment coupled to the tube. The equipment includes a vacuum source 9 for evacuating air or other material from respective sections of the tube, as defined by the valves 1.3, 14, 1 S, 16 and 1 7. For example, with valves 1 S and 16 closed, using channel 42, the vacuum source 9 can remove air or other gas from the section of the tube betw een the valves 14 and 15. Channels 41 , 43 and 44 enable the same functionality between valves 13 and 14; valves 15 and 16; and valves 16 and 17, .respectively. [0025] The implementation illustrated irs Figure 3 includes three material source reservoirs 10, 11, and 12, In one implementation, capsule filling material is provided by apparatus 10, plug material is provided by apparatus 11, and plug hardening material as provided fay apparatus 12. in this illustration, capsule fill materia! 0, plug material 11 and plug hardening material 12 are assumed to require only one step each. If multiple steps ar required, the same approach can be used by adding more valves, more connections to the vacuum source and more reservoirs of material. In addition, while a single vacuum source is illustrated in Figure 3, multiple sources can be used as necessitated by the materials to be removed, e.g. different gases or liquids.

10026] Not shown in Figure 3 are additional valves in each of channels 41 , 42, 43. and 44 used to decouple, the vacuum source 9 from tube 5 when materials from the reservoirs 10, 1 ! and 12 are to be provided. Similarly not shown are additional valves between -the reservoirs of material 10, 11, and 12 and tube 5. These valves decouple those material sources from tube 5 when the vacuum 9 is applied to a section of tube 5, as well as. to stop the How of material from sources 10, 11 and . 2 when sufficient material has been introduced into tube 3.

[0027] Next an example of use of the system illustrated in Figure 3 is described. A batch of empty capsules 1 enter through entrance port 7 when the valve 13 is opened and valve .14 is closed. Val ve 13 is then closed and a vacuum applied to evacuate the two chambers between closed valves 13 and 14, an between 14 and 15. Val e 14 is opened and capsules 1 move to the right (in this representation). This movement may be started by gravity or by a pressure differential between the two chambers or by impelling the capsules using mechanical, magnetic, electrical, or other means. Once valve 14 is closed, the capsules 1 are isolated and contained in the chamber defined by tube 5: and. closed valves 1.4 and 13. Fill material 10 is then introduced into the chamber defined by closed valves 14 and 15. The fill material 10 may be a solid (e.g. powder), a liquid, gel or a gas. and may be at elevated or reduced pressure relative to standard atmospheric pressure, as required by the particular materials. Using well known controllers, individual chambers between the various valves, and the various material sources 0, 1 1 and 12. can be maintained at desired pressures with respect to atmospheric pressure.

[0028] The fill material from reservoir .10 is then introduced into tube 5 where it fills the capsules 1. Next valve 15 opens and capsule .1 moves into the chamber defined by valves 15 and closed valve 16. Valve 15 is then closed. Plug material 11 is then introduced into the tube 5, immersing the capsules 1. Plug material 11 has characteristics suitable for filling the hole 2 in the capsules i . The chamber defined by closed valves 1 5 and 16 may be heated, cooled, pressurized, e vacuated or otherwise adapted to facilitate the plug material 11 entering hole 2 in capsule 1 in a controlled and desirable manner.

[0029] Next valve 16 is opened and capsule 1 moves to the right and Is contained in a chamber defined by tube S and closed valves 16 and 17. Plug hardening maierial 12 immerses capsule I causing plug material 1 1 to harden and complete the hole 2 filling/sealing process. Once this is complete, valve 17 opens and the batch of capsules 1 exit through exit port 8. The capsules I are now filled with fill material 10 at the desired pressure, and plugged wife plug material 1 1, thereby preventing fill material 10 from escaping.

[0030] Figure 4 is a cross-sectional view of the capsule I ready for use, sh owing hole 2 filled and plugged by fill materia! 10.

[003 1 ] The process just described is a generalized one suitable for filling capsules 1 with a variety of materials, and plugging the opening in the capsules with a variety of materials. Figure 5 illustrates, in more detail, how the generalized ideas described above can be used to fill a fusion power plant capsule with deuterium and tritium, and seal the capsule opening.

(0032] Figure 5 illustrates this process. As illustrated there, a batch of capsules I, like those illustrated in Figure 1, enter through valve 26 into a .chamber defined by tube 5 and closed valve 27» Once the capsules are in the tube 5. valve 26 is closed. Vacuum pump 18 is then used to evacuate the tube 5 and the capsules 1 therein. Once this is completed, valve 27 opens to allow capsules I to flow into a chamber defined by closed valve 30 and valve 27 when it is closed. Deuterium tritium isotope hydrogen fill gas 1 ^'flows into the defined chamber and fills the capsules 1 with gas .1 , Then valve 30 opens and the capsules flow into a section of tube 5 filed with an isolation liquid 31 that prevents the flow of the hydrogen fill gas 19 from out of the capsules. Isolation liquid 3 1 , however, does not enter the holes 2 in capsules 1 because of its viscosity and surface tension characteristics. The Isolation liquid is preferably a liquid exhibiting surface tension sufficient that it does not wet (has a high interface tension with) the capsule material. For capsule having opening holes under 0.5 mm in diameter water and oils are typical examples.

[0033] As the capsules flow through tube 5 they next contact hydrogen reactive material 32. Hydrogen reactive material 32 is a liquid or a gas and flows into hole 2 where it contacts the fill gas 19. The hydrogen reactive material reacts chemically to form a solid material plug. An example of a suitable hydrogen reactive material is a liquid unsaturated fat hydrogenating to become a solid, saturated fat. Other suitable substrates for hydrogenation include aikynes (formation of styrenes), nitriles, and iraines, all with or without catalysing agents. Other methods by which the capsules can be plugged include: use of low melting point metal, mercury, an adhesive, a cyanoacrylaie, a polymer, a raaterial that transitions from a gas to a solid, a material that transitions from a liquid to a solid, a material thai transitions from a powdered solid to a solid, UV curing materials and calcium bearing materials. Furthermore in some embodiments the capsule may be constructed with an .internal plug and thereby enable mechanical closure.

[0034] The capsules 1 then flow through tube 5 back into the. isolation liquid 31, that restricts the flow of the hydrogen reactive material 32. Then the capsules pass through valve 33. The capsules then come into contact with hydrogen gas 21 that reacts with any remaining hydrogen reacti ve material 32, thus completing the plugging .of hole 2.

[0035] Valve 28 opens allowing the capsules: to- flow into the chamber between valve. 28 and valve 29, Once contained in the chamber between valves 28 and 29, a vacuum pump 34 evacuates the chamber and backfills it with air. Finally, valve 29 opens and the capsules I are released into a suitable -carrier. The capsules may be cleaned of any external residual material by shaking or rolling in art. abrasive or by any of the -well-known, debarment and cleaning processes,

[0036] While the foregoing description of the invention enables one of ordinary skill to make and use what is considered -presently to be the best mode of the invention, it can be appreciated -that variations, combinations, and equivalents of the specific embodiment, method, and examples herein can be made. The invention should therefore not be limited by the above described embodiments, but is set forth in the claims below.

Claims

What is claimed is:

1. Apparatus for filling capsules having Openings therein, comprising:

an enclosure extending from a. first end to an opposite end;

a series of controllable dividers spaced along the enclosure for dividing the enclosure Into zones;

a first zone having a pump tor removing any material from within the capsule;

a second zone being coupled to a reservoir for introducing desired fill materia! into the capsules; and

a third zone for introducing pluggable material to close the openings s the capsules.

2. Apparatus as in claim 1 wherein the enclosure comprises a^'tube, and the series of controllable dividers spaced along the enclosure comprise valves.

3. Apparatus .as in claim 2 wherein the fill materiai comprises hydrogen.

4. Apparatus as in claim 3 wherein the fill material comprises deuterium and tritium.

5. Apparatus as in claim 3 wherein the pluggable material comprises a material which reacts with hydrogen.

6. Apparatus as in claim 1 wherein the third zone includes a first portion which, prevents the fill material, .from escaping from the capsules, a second portion in which the pluggable material is introduced, and a third portion in which the pluggable material is cured to seal the openings in the capsules,

7. Apparatus as in claim .1 wherein the pump comprises a vacuum pump.

8. Apparatus as in claim 1 wherein the controllable dividers comprise valves.

9. Apparatus as in claim 1 wherein the capsules move from the first zone to the second zone, and from the second zone to the third zone by gravity flow.

10. Apparatus as in claim 1 wherein the capsules comprises one of paintbalis, pharmaceuticals, or bullets.

! 1. Apparatus comprising:

a longitudinally extending enclosure interrupted at intervals by controllable closures, the closures being operable to form isolated chambers within the enclosure, the isolated chambers being independently equipped wills process equipment to evacuate and fill the isolated chambers with desired constituents; and

batche of capsules are processed through the enclosure by being positioned in the isolated chambers and subjected t« the desired constituents before being moved to subsequent isolated chambers for further processing by the desired constituents.

12, A method of introducing desired material int ^'capsules, each having at least one opening in a capsule wait, comprising:

introducing the capsules into a first zone of an enclosure having, a series of zones defined by controllable dividers;

using the controllable dividers, isolating the capsules in the first zone;

introducing the desired material into the first zone and into the capsules in the first zone;

moving the capsules to a second ¾one;.

isolating the capsules in the second zone; and

introducing -a sealant into the second zone to seal the openings in the capsules.

13, A method as in claim J 2 wherein the enclosure comprises a tube, the

controllable dividers comprise valves, and each of. the. steps of , isolating the .-capsules in the first zone and isolating the capsules in the second zone comprises opening and closing valves to separate the first zone from the second zone.

14, A method -of introducing isotopes of hydrogen into capsules, each having a fill hole in the wail thereof, the method comprising:

opening a first valve to allow a batch of capsules to flow into a first portion of an enclosure, the first portion being separated from the remainder of the enclosure by a second valve; introducing the isotopes of hydrogen Into the first portion of the enc losure and thereby into the batch of capsules;

opening the second valve to allow the batch of capsules to flow into a second poriion of the enclosure, the second portion of the enclosure being separated from remaining portions of the enclosure by a third valve;

introducing a sealant into the second portion of the enclosure to seal the fill holes in the batch of capsules; and

opening the third valve to allow the batc of capsules to flow out of the second portion of the enclosure.

15. A method as in claim 14 wherein the method further comprises, after fee step of opening the third valve, steps of;

confining the capsules in a third portion of the enclosure between the third valve and a fourth valve;

Introducing a reactant in the third portion of the enclosure, the reactant combining with the sealant to seal the till holes in the hatch of capsules.

16. A method as In claim 15 wherein, after the step of introducing the isotopes of hydrogen, a step is performed of imniersing the capsules in a fluid to prevent escape of the isotopes of hydrogen,

17. A. method as in claim 14 wherein prior to the step of introducing the isotopes of hydrogen into the first portion of the enclosure a step is performed of evacuating the atmosphere from the first portion of the enclosure.