DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of Claims
A reply was filed on 01/13/2026. The amendments to the claims, drawings, and specification have been entered. Claims 1-13 are pending in the application with claims 4 and 13 withdrawn. Claims 1-3 and 5-12 are examined herein.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Drawings
The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the following features in claims 5 and 12 must be shown or the features canceled from the claims. No new matter should be entered.
Claim 5: “each of the fuel tubes comprises an upper section which contains a respective first gas space”, “a coolant gas space located above the coolant liquid”, and “a second gas space in contact with the coolant liquid” – as best understood by Examiner (see discussion below), claim 5 requires three different “gas space[s]”: “a first gas space” (claims 1, 5), “a coolant gas space” (claim 5), and “a second gas space” (claim 5). However, the figures only show a gas space (207) in each of the fuel tubes and a gas space (unlabeled) above the coolant (203) (FIG. 2). The figures therefore do not appear to show the three different “gas space[s]” recited in claim 5.
Claim 12: “wherein the cooling system is configured such that a region at a bottom of each of the fuel tubes is not cooled directly by the coolant liquid” – claim 12, which depends on claim 1, requires fuel tubes that are at least partially immersed in a coolant tank containing a coolant liquid (claim 1) and a bottom of each of the fuel tubes is not directly cooled by the coolant liquid. However, the figures appear to show the bottom of each fuel tube in direct contact with the coolant liquid (FIG. 2). The figures therefore do not appear to show a mechanism by which a bottom of each of the fuel tubes is “not cooled directly by the coolant liquid” while the fuel tubes are partially immersed in the coolant tank.
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they include the reference character “601” (FIG. 6) which is not mentioned in the description. Examiner notes, there do not appear to be any amendments to Figure 6 in the amended drawings filed on 01/13/2026 (see also Remarks, p. 6).
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the Applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Claim Objections
Claims 6 and 8 are objected to because of the following informalities:
Claim 6: “across the fuel tube” should be amended to recite “across the respective fuel tube”
Claim 8: “the upper section” should be amended to recite “an upper section”
Appropriate correction is required.
Claim Rejections - 35 USC § 112(a)
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
Claim 5 is rejected under 35 U.S.C. 112(a) as failing to comply with the written description requirement. The claim contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, at the time the application was filed, had possession of the claimed invention.
Claim 5, as currently presented, requires “each of the fuel tubes comprises an upper section which contains a respective first gas space; at least part of the upper section of each of the fuel tubes protrudes into a coolant gas space located above the coolant liquid during operation of the reactor; the molten salt fission reactor further comprises a gas cooling system configured to cool a second gas space in contact with the coolant liquid”. There does not appear to be sufficient support for these features in the original disclosure. Specifically, as discussed above, the claim would appear to require three different “gas space[s]”: “a first gas space” (claims 1, 5), “a coolant gas space” (claim 5), and “a second gas space” (claim 5). However, the original figures only show a gas space (207) in each of the fuel tubes and a gas space (unlabeled) above the coolant (203) (FIG. 2). The original specification similarly only appears to discuss two different gas spaces (i.e., a gas space in the fuel tube and a gas space above the coolant) (10:6-25) and the original claims similarly recite “each fuel tube comprises an upper section which contains the respective gas space” and “a coolant gas space located above the coolant liquid” (claim 5). Thus, neither the original drawings, the original specification, nor the original claims show, disclose, or recite a reactor having the three different gas spaces as currently required by claim 5. This feature is therefore new matter.
Claim Rejections - 35 USC § 112(b)
Claims 1-3 and 5-12 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor regards as the invention.
Claims 1-3 recite functional limitations of the claimed “fuel salt cooling system”. A claim limitation is functional when it recites a feature by what it does rather than by what it is. When claims merely recite a description of a problem to be solved or a function or result achieved by the invention, the boundaries of the claim scope may be unclear. In this case, the functional limitations fail to define or even imply the structure that is required of the “fuel salt cooling system” to achieve the recited functions. The claims do not provide a discernable boundary on what performs the recited functions and the recited functions do not follow from the structures of the “fuel salt cooling system” recited in the claims (i.e., the coolant tank and the heat exchanger). It is therefore unclear whether the function requires some other structure(s) or is simply a result of operating the “fuel salt cooling system” in a certain manner. Accordingly, one of ordinary skill in the art would be unable to ascertain the metes and bounds of the claims. The claims appear to be directed towards a specific design and/or arrangement and/or operation of the reactor and/or “fuel salt cooling system” (see 8:21-24, 9:1-10:9). However, it is unclear from the claims the structure(s), design, arrangement of structures, and/or operation of the reactor and/or “fuel salt cooling system” that enable the “fuel salt cooling system” to achieve the recited functions. The claims therefore merely recite a description of a problem to be solved or a function or result achieved by the invention and the boundaries of the claim scope are unclear.
As best understood by Examiner, the claimed functions of the “fuel salt cooling system” (e.g., the temperature meeting the expressions in claims 1 and 2 and the temperature at the gas interface being less than the temperature at other regions of the fuel tube) are achieved by reducing the temperature at the gas-fuel salt interface. For example, Applicant states that achieving the claimed functions “would merely require adaptation over a more typical reactor configuration where the top of the fuel salt wound [sic] tend to be hottest (as hot fluids rise)” (Remarks, p. 7) and the specification discloses:
“If the temperature of the fuel salt at the top of the tube can be maintained at a lower level than the temperature lower down the fuel column, then gas bubbles cannot form and gas will exit the fuel salt by diffusion across the gas interface” (3:22-24),
“This results in a cooling of the very uppermost layer of the fuel salt, creating the low temperature gas/salt interface needed to maintain the fuel salt below the saturating gas concentrations in the bulk of the fuel salt” (10:30-32), and
“the reactor is configured such that
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. It should be noted that the examples discussed earlier where T2>T1 will always satisfy this relationship, as the right hand side will always be less than T1” (14:15-18).
The specification further discloses that this temperature reduction can be achieved by having the coolant flow downwardly (9:1-5), or, if the coolant flow cannot be reversed, the specification discloses (9:7-10:9):
“[I]t is still possible to ensure that the upper surface of the fuel salt is the point of lowest gas solubility in the fuel salt ... by one or a combination of the following methods:
...[R]educing heat production in the fuel salt [] close to the top of the tube [] by screening it with neutron absorbing materials []
Introducing a secondary flow of cool coolant salt to cool the top region of the fuel tube and fuel salt
Cooling the gas space above the fuel salt in the tube to temperatures lower than the lowest temperature of the tube wall anywhere in the tube so that convection of the gas cools the upper surface of the fuel salt despite the coolant outside the tube at that surface level being hotter. This cooling of the gas space can be achieved by a supplementary flow of cooler coolant salt, emergence of the part of the fuel tube containing gas above the surface of the coolant salt into a region of lower temperature or actively passing cool gas into the gas space in the fuel tube.
...[P]lacing a baffle ... a short distance below the fuel salt surface [] so that bulk convective flow from the hot region further down the tube does not reach the surface while still allowing slow mixing of molten salt [] and diffusion of gas through the baffle to the surface
Maintaining a relatively slow flow velocity of the coolant so that the wall of the tube at the bottom, where coolant temperature is lowest, is intermediate between the temperature of the bulk fuel salt and the coolant salt with that intermediate temperature being higher than the surface temperature of the fuel salt at the top of the tube. In this method it is possible that the gas space above the fuel, in contact with the fuel tube above the level of the fuel salt, is cooler than the walls of the tube where the coolant is at its lowest temperature but is in contact with the hot fuel salt.
Providing an insert to displace the salt from the centre of the tube in a region near and at the surface, keeping only a thin perimeter of salt in contact with the walls. This thin band of salt will have the same cooled surface area as before, but with only a small volume to generate heat. Thus, the remaining salt will be kept cool by the coolant
Adding insulation to the bottom of the fuel tube to increase the temperature of the fuel inside
...[I]njecting coolant [] above the bottom of the fuel tube[], leaving a lower section [] uncooled”
However, none of these mechanisms and/or structures appear to be recited or suggested in the claims. For example, claims 1-3 do not appear to recite neutron absorbing materials at a top of the fuel tubes or a secondary flow of coolant salt. Thus, the claims appear to recite functional limitations of the claimed “fuel salt cooling system” that are not clearly linked to the structure(s) that perform these limitations.
Claim 5 recites “each fuel tube comprises an upper section which contains a respective first gas space; at least part of the upper section of each of the fuel tubes protrudes into a coolant gas space located above the coolant liquid during operation of the reactor; the molten salt fission reactor further comprising a gas cooling system configured to cool a second gas space in contact with the coolant liquid”. The relationship between the “coolant gas space located above the coolant liquid during operation of the reactor” and the “second gas space in contact with the coolant liquid” is unclear in view of the drawing objection and 35 U.S.C. 112(a) rejection above.
Claim 7 recites “the fuel tube”. However, parent claim 1 previously recites “a plurality of fuel tubes”. It is therefore unclear if the claim is intending to refer to each of the previously recited fuel tubes, a specific one of the previously recited fuel tubes, or something else. It is further unclear what feature the “top of a critical region” is a “top” of and what feature the “critical region” is a “region” of in the claim.
Claim 9 recites “wherein the cooling system is configured to direct a secondary flow of coolant salt to a top region of the fuel tube”. It is unclear the relationship between the “coolant salt” recited in claim 9 and the “fuel salt”, “molten salt”, and “coolant liquid” previously recited in parent claim 1. Is the “coolant salt” referring to the same feature as the previously recited “fuel salt” and “molten salt”, the same feature as the “coolant liquid”, or a different feature? Examiner notes, the figures only appear to show a single “coolant” (103, 203, 303). Additionally, the phrase “secondary” appears to suggest at least two flows of coolant salt. However, there does not appear to be a previous recitation of a “flow” and the figures only appear to show a single flow of the coolant (203, 303) (see 9:7-14). Is the claim intending to recite the coolant liquid is another molten salt and the coolant liquid flows to a top region of the fuel tube? Additionally, parent claim 1 previously recites “a plurality of fuel tubes”. It is therefore unclear if the claim is intending to refer to each of the previously recited fuel tubes, a specific one of the previously recited fuel tubes, or something else.
Claim 12 recites “wherein the cooling system is configured such that a region at a bottom of each of the fuel tubes is not cooled directly by the coolant liquid”. This feature is unclear in view of the above drawing objections. The claim appears to suggest the cooling system indirectly cools the bottom of the fuel tubes. However, it is unclear what structure(s) or feature(s) of the claimed cooling system enable the system to cool the bottom of the fuel tubes in this manner. The claim appears to describe a function of the cooing system that is not clearly linked to the structure(s) that perform the claimed function. Accordingly, one of ordinary skill in the art would be unable to ascertain the metes and bounds of the claims.
Any claim not explicitly addressed above is rejected because it is dependent on a rejected base claim.
Note on Claim Interpretation
The claims include limitations which appear to be statements of intended or desired use. For example, claim 1 recites “the fuel salt cooling system is configured such that during operation of the reactor, for all points within the fuel salt within each of the fuel tubes except at the respective gas interface:
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”, claim 2 recites “wherein the fuel salt cooling system is configured such that during operation of the reactor, for all points within the fuel salt within each of the fuel tubes except at the respective gas interface:
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”, claim 3 recites “wherein the temperature T1 of the fuel salt at each of the gas interfaces is less than the temperature T2 of the fuel salt in all other regions of the respective fuel tube”, and claim 7 recites “a flow rate of the coolant liquid and a power density of the fuel salt are such that a temperature of a wall of the fuel tube at a bottom of the fuel tube is greater than a temperature of the coolant liquid at a top of a critical region”. These clauses, as well as other statements of intended use, do not serve to patentably distinguish the claimed structure over that of the prior art as long as the structure of the prior art is capable of performing the intended use. See MPEP 2111-2115. As discussed above and as best understood by Examiner in view of the 35 U.S.C. 112(b) rejections above, the features recited in claims 1-3 is achieved by reducing the temperature at the top of the fuel tube, e.g., by providing neutron absorbing materials at the top of the fuel tube, etc. (3:22-24, 9:7-10:9, 10:30-32, 14:15-18).
Claim Rejections - 35 USC § 102
Claims 1-3, 5, 7-9, and 12, as best understood, are rejected under 35 U.S.C. 102(a)(1) as being anticipated by US Publication No. 2016/0005497 (“Scott”).
Regarding claims 1-3, Scott (previously cited) (see FIGS. 1-2) discloses a molten salt fission reactor (100) ([0001]) comprising:
a reactor core (“core”) comprising a plurality of fuel tubes (102) ([0015], [0034]), each fuel tube containing:
a fuel salt (“molten fuel salt”), the fuel salt being a molten salt of one or more fissile isotopes ([0015], [0034], [0062], [0167]);
a gas interface of the fuel salt, which is a surface of the fuel salt in contact with a first gas space (“gas space”) during operation of the reactor ([0046], [0085], [0118], [0165]);
a fuel salt cooling system configured to cool the fuel salt, the fuel salt cooling system comprising
a coolant tank (101) containing a coolant liquid (“coolant”, “blanket salt”) in which the fuel tubes are at least partially immersed ([0015], [0034]-[0035], [0165]), and
a heat exchanger (103) for extracting heat from the coolant liquid ([0015], [0034]-[0035]).
Scott discloses maintaining an upper portion of each of the fuel tubes subcritical while maintaining the remainder of each of the fuel tubes critical ([0034]-[0035], [0047]). This would result in fewer fission reactions in the upper portion of each of the fuel tubes1, and, therefore a lower temperature at the upper portions (see also [0007]; see also instant specification, 9:7-12, 13:1-3). Thus, as discussed above and further below, as best understood by Examiner, Scott discloses wherein:
(claim 1) the fuel salt cooling system is configured such that during operation of the reactor, for all points within the fuel salt within each of the fuel tubes except at the respective gas interface:
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where:
T1 is the temperature of the fuel salt at the gas interface;
T2 is the temperature of the fuel salt at a measured point;
P1 is the absolute pressure at the gas interface;
P2 is the absolute pressure at the measured point;
RHe is the gas constant of Helium;
ΔHHe is the enthalpy of solution of Helium in the fuel salt,
(claim 2) the fuel salt cooling system is configured such that during operation of the reactor, for all points within the fuel salt within each of the fuel tubes except at the respective gas interface:
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where:
RX is the gas constant of a noble gas;
ΔHX is the enthalpy of solution of the noble gas in the fuel salt;
the noble gas is one of Neon, Argon, Krypton, or Xenon, and
(claim 3) the temperature T1 of the fuel salt at each of the gas interfaces is less than the temperature T2 of the fuel salt in all other regions of the respective fuel tube.
Regarding claim 5, Scott discloses the molten salt fission reactor according to claim 1. Scott discloses (see FIGS. 1-2):
each of the fuel tubes comprises an upper section which contains the respective first gas space ([0046], [0085], [0118], [0165]);
at least part of the upper section of each of the fuel tubes protrudes into a coolant gas space located above the coolant liquid during operation of the reactor ([0165]-[0166], [0171]);
the molten salt fission reactor further comprises a gas cooling system (“off gas system”) configured to cool a second gas space in contact with the coolant liquid ([0085], [0118]-[0121], [0165]).
Regarding claim 7, Scott discloses the molten salt fission reactor according to claim 1. Scott discloses the coolant liquid circulates through the fuel tubes only by natural convection ([0035]-[0036]), and a flow rate of the coolant liquid and a power density of the fuel salt are such that a temperature of a wall of each of the fuel tubes at a bottom of each of the fuel tubes is greater than a temperature of the coolant liquid at a top of each of the fuel tubes (see above discussion regarding claims 1-3). Additionally, Scott discloses the ability to adjust the flow rate and power density ([0036]). Thus, Scott’s system would be capable of having a flow rate of the coolant liquid and a power density of the fuel salt such that a temperature of a wall of each of the fuel tubes at a bottom of each of the fuel tubes is greater than a temperature of the coolant liquid at a top of a critical region as recited in claim 7.
Regarding claim 8, Scott discloses the molten salt fission reactor according to claim 1. Scott discloses an upper section of each of the fuel tubes includes neutron absorbing material ([0040]; as noted by Scott, all materials have some neutron absorbing capability). Additionally, as discussed above with regards to claims 1-3, Scott discloses heat production of the fuel salt within the upper section of each of the fuel tubes is less than in the rest of the fuel salt within each of the fuel tubes ([0007], [0034]-[0035], [0047]; see also instant specification, 9:7-12, 13:1-3).
Regarding claim 9, Scott discloses the molten salt fission reactor according to claim 1. Scott discloses the coolant liquid is a coolant salt ([0034]-[0035], [0060], [0163]) and the cooling system is configured to direct a flow of the coolant liquid to a top region of each of the fuel tubes (FIG. 1).
Regarding claim 12, Scott discloses the molten salt fission reactor according to claim 1. Scott discloses a region at a bottom of each of the fuel tubes is also cooled by natural convection of the fuel salt within the fuel tubes, not just by direct thermal conduction of heat from the fuel salt, through the fuel tube, to the coolant liquid ([0038]-[0039], [0042], [0044]).
Claim Rejections - 35 USC § 103
Claims 6 and 10, as best understood, are rejected under 35 U.S.C. 103 as being unpatentable over Scott.
Regarding claim 6, Scott discloses the molten salt fission reactor according to claim 1. Scott further teaches an embodiment in which each of the fuel tubes comprises a baffle (400) immersed in the fuel salt which extends across the respective fuel tube (FIG. 4). Scott teaches the baffle provides the advantages of improving convection of the fuel salt within the fuel tubes ([0045]). It would have therefore been obvious to a person having ordinary skill in the art before the effective filing date (“POSA”) to include a baffle in each of the fuel tubes, as taught by Scott, for the heat transfer benefits thereof. Thus, modification of Scott’s reactor in order to improve convection and heat transfer efficiency, as suggested by Scott, would have been obvious to a POSA.
Regarding claim 10, Scott discloses the molten salt fission reactor according to claim 1. Scott further teaches an embodiment in which each of the fuel tubes comprises a displacement element (602, 603) extending from the respective gas interface into the fuel salt, each of the displacement elements being configured to displace the fuel salt from a central axis of the respective fuel tube (FIG. 6, [0049]). Scott teaches the displacement element provides the advantages of increasing heat transfer from the fuel salt to the fuel tube wall ([0048]-[0049]). It would have therefore been obvious to a POSA to include a displacement mechanism in each of the fuel tubes, as taught by Scott, for the heat transfer benefits thereof. Thus, modification of Scott’s reactor in order to improve heat transfer, as suggested by Scott, would have been obvious to a POSA.
Claim 11, as best understood, is rejected under 35 U.S.C. 103 as being unpatentable over Scott in view of US Publication No. 2022/0361701 (“Schoofs”).
Regarding claim 11, Scott discloses the molten salt fission reactor according to claim 1, but does not appear to disclose a bottom of each of the fuel tubes is more thermally insulating. However, Scott discloses it is desirable to improve heat transfer within the fuel salt by convective mixing of the fuel salt within the fuel tubes ([0041]-[0043]). Schoofs (previously cited) is similarly directed towards improving heat transfer within a fluid by convective mixing of the fluid within a container ([0155]). Schoofs teaches a region at a bottom of the container may be more thermally insulating than other regions of the container ([0158]-[0160]). Schoofs further teaches this facilitates convection ([0155], [0159]). It would have therefore been obvious to a POSA to have a bottom of the fuel tubes that is more thermally insulating, as taught by Schoofs, for the heat transfer benefits thereof. Thus, modification of Scott in order to enhance and maintain convective flow of the fuel salt within the fuel tubes, as suggested by Schoofs, would have been obvious to a POSA.
Response to Arguments
Applicant’s amendments to the drawings and specification overcome some, but not all, of the prior drawing objections as discussed above.
Applicant’s amendments to the claims overcome the prior claim objections, but have created new issues as discussed above.
Applicant’s amendments to the claims overcome some, but not all, of the prior 35 U.S.C. 112(b) rejections of record and have created new issues as discussed above.
Applicant argues Scott does not anticipate the features of claim 1 because “there is not sufficient evidence in Scott to support the Examiner’s assertion that it would result in the temperature relationship recited in independent claim 1” (Remarks, pp. 9-10).
Scott discloses the molten salt reactor of claim 1 for at least the following reasons: (1) Scott discloses all of the structural features recited in claim 1, (2) Scott discloses all of the structural features of the molten salt reactor disclosed by the instant specification as resulting in the temperature relationship recited in claim 1, and (3) Scott discloses applying at least one of the methods disclosed by the instant specification as resulting in the temperature relationship recited in claim 1.
(1) As discussed in the prior Office action and above, the feature of “the fuel salt cooling system is configured such that during operation of the reactor, for all points within the fuel salt within each of the fuel tubes except at the respective gas interface:
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” is a functional limitation, the metes and bounds of which are unclear. This limitation, as well as other statements of intended use, do not serve to patentably distinguish the claimed structure over that of the prior art as long as the structure of the prior art is capable of performing the intended use. See MPEP 2111-2115. Scott discloses all of the structural features of the molten salt fission reactor of claim 1 (e.g., the reactor core, the fuel tubes, the fuel salt cooling system) as discussed above. Thus, if the reactor having the structure recited in claim 1 is capable of resulting in the temperature relationship recited in claim 1, it follows that Scott’s reactor, having all of the recited structure, would also be capable of resulting in the temperature relationship recited in claim 1.
(2) The instant specification discloses:
“Figure 2 shows a static MSR with upward coolant flow. The static molten salt reactor has vertically oriented fuel tubes 205 where the top, gas filled portion 207 of the fuel tube emerges from circulating coolant salt 203 into a region of a lower temperature than the coolant salt. The coolant salt circulates by natural convection 204 through the core and a heat exchanger 208. The gas space above the coolant salt is cooled by a cool gas system comprising a cool gas inlet 201 and a cool gas outlet 202, and in turn cools the upper portion of the fuel tube which in turn cools the gas inside the fuel tube, being heated by contact with the upper surface of the fuel salt and then rising up the centre of the fuel tube. This results in a cooling of the very uppermost layer of the fuel salt, creating the low temperature gas/salt interface needed to maintain the fuel salt below saturating gas concentrations in the bulk of the fuel salt” (10:16-27)
The instant specification would therefore appear to suggest that a static MSR having the structure described above would be capable of resulting in the temperature relationship recited in claim 1.
Scott discloses a static MSR ([0001], [0015]; see instant specification 1:21-28) with upward coolant flow (see arrows indicating circulation path of coolant in FIG. 1) having vertically oriented fuel tubes (102) ([0034]) where the top, gas filled portion (“gas space”) of the fuel tube emerges from circulating coolant salt into a region of a lower temperature than the coolant salt ([0085], [0118]-[0120], [0165], [0171]), the coolant salt circulates by natural convection through the core and a heat exchanger (103) ([0015], [0035]-[0036]), and the gas space above the coolant salt is cooled by a cool gas system comprising a cool gas inlet and a cool gas outlet ([0165]-[0166], [0171]), i.e., the same structure as the static MSR described in the instant specification. Thus, if the static MSR having the structure described in the above cited portion of the instant specification is capable of resulting in a cooling of the very uppermost layer of the fuel salt, creating the low temperature gas/salt interface needed to maintain the fuel salt below saturating gas concentrations in the bulk of the fuel salt (i.e., the temperature relationship recited in claim 1), it follows that Scott’s reactor, having all of the disclosed structure, would also be capable of resulting in the temperature relationship recited in claim 1.
(3) The instant specification also discloses (emphasis added):
“Where reversal of coolant flow direction is not possible, for example in static molten salt reactors where coolant flow is by natural convection, it is still possible to ensure that the upper surface of the fuel salt is the point of lowest gas solubility in the fuel salt. This can be achieved by one or a combination of the following methods:
...[R]educing heat production in the fuel salt [] close to the top of the tube [] by screening it with neutron absorbing materials []
Introducing a secondary flow of cool coolant salt to cool the top region of the fuel tube and fuel salt
Cooling the gas space above the fuel salt in the tube to temperatures lower than the lowest temperature of the tube wall anywhere in the tube so that convection of the gas cools the upper surface of the fuel salt despite the coolant outside the tube at that surface level being hotter. This cooling of the gas space can be achieved by a supplementary flow of cooler coolant salt, emergence of the part of the fuel tube containing gas above the surface of the coolant salt into a region of lower temperature or actively passing cool gas into the gas space in the fuel tube.
...[P]lacing a baffle ... a short distance below the fuel salt surface [] so that bulk convective flow from the hot region further down the tube does not reach the surface while still allowing slow mixing of molten salt [] and diffusion of gas through the baffle to the surface
Maintaining a relatively slow flow velocity of the coolant so that the wall of the tube at the bottom, where coolant temperature is lowest, is intermediate between the temperature of the bulk fuel salt and the coolant salt with that intermediate temperature being higher than the surface temperature of the fuel salt at the top of the tube. In this method it is possible that the gas space above the fuel, in contact with the fuel tube above the level of the fuel salt, is cooler than the walls of the tube where the coolant is at its lowest temperature but is in contact with the hot fuel salt.
Providing an insert to displace the salt from the centre of the tube in a region near and at the surface, keeping only a thin perimeter of salt in contact with the walls. This thin band of salt will have the same cooled surface area as before, but with only a small volume to generate heat. Thus, the remaining salt will be kept cool by the coolant
Adding insulation to the bottom of the fuel tube to increase the temperature of the fuel inside
...[I]njecting coolant [] above the bottom of the fuel tube[], leaving a lower section [] uncooled” (9:1-10:4; see also 3:22-32)
The instant specification would therefore appear to suggest that applying at least one of the above methods to a static MSR would also result in the temperature relationship recited in claim 1.
Scott discloses a static MSR ([0001], [0015]; see instant specification 1:21-28) and discloses reducing heat production in the fuel salt close to the top of the tube. Specifically, Scott discloses maintaining an upper portion of each of the fuel tubes subcritical while maintaining the remainder of each of the fuel tubes critical ([0034]-[0035], [0047]), which would result in fewer fission reactions in the upper portion of each of the fuel tubes2, and, therefore a lower temperature at the upper portions (see also [0007]; see also instant specification, 9:7-12, 13:1-3). Scott also discloses cooling the gas space above the fuel salt in the tube by providing a part of the fuel tube containing gas above the surface of the coolant salt into a region of lower temperature and actively passing cool gas into the gas space in the fuel tube ([0085], [0118]-[0120], [0165], [0171]). Further, Scott discloses a velocity of the coolant may be adjust ([0036]). Thus, Scott’s system would be capable of maintaining a flow velocity of the coolant in a particular manner. Thus, if a static MSR, applying one or a combination of the above disclosed methods is capable of ensuring that the upper surface of the fuel salt is the point of lowest gas solubility in the fuel salt (i.e., the temperature relationship recited in claim 1, it follows that Scott’s static MSR, which is disclosed as applying one or a combination of the above disclosed methods, would also be capable of resulting in the temperature relationship recited in claim 1.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. Prosecution on the merits is closed. See MPEP 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
RCE Eligibility
Since prosecution is closed, this application is now eligible for a request for continued examination (RCE) under 37 CFR 1.114. Filing an RCE helps to ensure entry of an amendment to the claims, specification, and/or drawings.
Interview Information
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, Applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
Contact Information
Examiner Jinney Kil can be reached at (571) 272-3191, on Monday-Thursday from 8:30AM-6:30PM ET. Supervisor Jack Keith (SPE) can be reached at (571) 272-6878.
/JINNEY KIL/Examiner, Art Unit 3646
1 https://en.wikipedia.org/wiki/Nuclear_reactor_physics
2 https://en.wikipedia.org/wiki/Nuclear_reactor_physics