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 .
Election/Restrictions
Applicant's election with traverse of Group I in the reply filed on 9/15/2025 is acknowledged. The traversal is on the ground(s) that the groups are related. This is not found persuasive because at least the reason that, as shown on page 2 of the 7/14/2025 Requirement for Restriction/Election, each grouping of claims belongs to a disparate classification group than each other grouping. Applicant’s election of the species shown, respectively, in Fig. 3A, Figs. B3, 4A-B, and Fig. 4C in the reply filed on 9/15/2025 is acknowledged. The traversal is on the ground(s) that there are a large number of generic claims. This argument is not found persuasive because, as described in MPEP 808.01(a), even with a large number of generic claims, restriction may be appropriate when “the generic claims recite or encompass such a multiplicity of species that an unduly extensive and burdensome search would be necessary to search the entire scope of the claim,” which is the case here, as shown by the large number of groups and species.
The requirement is still deemed proper and is therefore made FINAL.
Drawings
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because reference characters "40" and "40a" have both been used to designate the entire fuel element section (e.g., Fig. 1, 40) as well as individual fuel elements (e.g., it appears Fig. 4E #40 should be 40a, Figs. 5-6 #40 should be 40a, Fig. 10A the two #40s should each be a 40a, and Fig. 10B #40 should be 40a). Please check the Drawings for any further discrepancies missed by Examiner. Please also check the Specification to ensure the numerals 40 and 40a are correct.
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. 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
Claim 3 objected to because of the following informalities: it is missing the verb “is” in line 2. Appropriate correction is required.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
For Applicant’s benefit, portions of the cited reference(s) have been cited to aid in the review of the rejection(s). While every attempt has been made to be thorough and consistent within the rejection, it is noted that the prior art must be considered in its entirety, including disclosures that teach away from the claims. See MPEP 2141.02 VI.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 3, 5, 7, 9, 10, 11, 12, 13, 14, 22, and 23 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Sterbentz (US 2018/0226159).
Regarding claim 1, Sterbentz discloses (see especially figs. 2E, 2F, 2G) a heat pipe fuel element (250), comprising: an evaporation section (220); a condensing section (222); a capillary section (228) connecting the evaporation section to the condensing section; and a primary coolant (210), wherein, in the evaporation section and in a cross-section in a plane perpendicular to a longitudinal axis of the evaporation section, the heat pipe fuel element includes a cladding layer (202) enclosing an interior area including a fuel body (204), wherein the fuel body (204) has an outer surface oriented toward the cladding layer (202) and an inner surface defining a periphery of a vaporization space of the evaporation section (see Fig. 2I: a radially interior portion of fuel section 204 surrounds at least a portion of the evaporation section 220), and wherein the fuel body (204) is formed of a fissionable fuel composition (¶ 43).
Regarding claim 3, Sterbentz anticipates all the elements of the parent claim and further discloses wherein the evaporation section (220) is at a first end (left end per fig. 2F) of the heat pipe fuel element and the condensing section (222) is at a second end (right end) of the heat pipe fuel element.
Regarding claim 5, Sterbentz anticipates all the elements of the parent claim and further discloses wherein the capillary section (228) includes a wick structure in contact with an interior surface of the heat pipe fuel element (see fig. 2F: “The liquid 226 may be absorbed by a wick 228, which may extend around a central portion of the heat pipe 208,” ¶ 49).
Regarding claim 7, Sterbentz anticipates all the elements of the parent claim and further discloses wherein the condensing section (222) is elevated relative to the evaporation section (220) (see Fig. 2I).
Regarding claim 9, Sterbentz anticipates all the elements of the parent claim and further discloses wherein the primary coolant is a liquid metal (e.g., sodium, ¶ 48).
Regarding claim 10, Sterbentz anticipates all the elements of the parent claim and further discloses wherein the liquid metal is sodium or a sodium-containing alloy (e.g., sodium, ¶ 48).
Regarding claim 11, Sterbentz anticipates all the elements of the parent claim and further discloses (fig. 2G) wherein the cladding layer (202) forms at least a portion of an exterior wall of the heat pipe fuel element (250).
Regarding claim 12, Sterbentz anticipates all the elements of the parent claim and further discloses (Fig. 2I) wherein, in the evaporation section (220), the cladding layer (202) is a seamless continuous tube.
Regarding claim 13, Sterbentz anticipates all the elements of the parent claim and further discloses wherein, in the evaporation section and in the cross-section in the plane perpendicular to the longitudinal axis of the evaporation section, the cladding layer enclosing the interior area has a shape of a polygon (“The outer cladding 202 may have a polygonal shape,” ¶ 39).
Regarding claim 14, Sterbentz anticipates all the elements of the parent claim and further discloses wherein the polygon is a quadrilateral (“The outer cladding 202 may have a polygonal shape, a square shape, a rectangular shape, a triangular shape, a circular shape, a hexagonal shape, or another shape,” ¶ 39).
Regarding claim 22, Sterbentz anticipates all the elements of the parent claim and further discloses wherein the uranium-based fissionable fuel composition includes uranium having an enrichment of up to 20% (“low-enriched uranium dioxide,” ¶ 43), and wherein a specific enrichment of the fuel body (% enrichment per unit volume) is constant ± 2% (LEU usable as reactor fuel is understood to be 3-5% enrichment).
Regarding claim 23, Sterbentz anticipates all the elements of the parent claim and further discloses wherein the uranium-based fissionable fuel composition includes uranium nitride, uranium oxide, U10Mo, or a cermet thereof (“low-enriched uranium dioxide,” ¶ 43).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
For Applicant’s benefit, portions of the cited reference(s) have been cited to aid in the review of the rejection(s). While every attempt has been made to be thorough and consistent within the rejection, it is noted that the prior art must be considered in its entirety, including disclosures that teach away from the claims. See MPEP 2141.02 VI.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Sterbentz in view of Dulloo (US 2022/0139581).
Regarding claim 2, Sterbentz anticipates all the elements of the parent claim but does not explicitly disclose a moderator between the outer surface of the fuel body and an interior surface of the cladding layer.
Dulloo does. Dulloo is in the same art area of heat pipes for nuclear reactors and teaches (fig. 2) a heat pipe (200) having a moderator (202), a cladding (222), and a fuel (228), wherein the pictured moderator and fuel may be inverted (¶ 31: “the position of the fuel 228 and moderator in fig. 2 can be inverted”). The skilled artisan would have been motivated to try this alternate configuration because, as described by Dulloo (¶ 31), in order to “accommodate for less efficient cooling in the event of heat pipe failure” based on “the intended application and/or user preference.”
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Sterbentz in view of Pivovar1 (High temperature microporous coatings: The effects of wetting and wicking on nucleate boiling and CHF2).
Regarding claim 6, Sterbentz anticipates all the elements of the parent claim but does not explicitly disclose wherein the wick structure is a mesh of sintered metal.
Pivovar does teach this. Pivovar is also in the art area of nuclear reactors and teaches a wick structure using a mesh of sintered metal (“a mesoporous sintered mesh,” § 5.1.2 Wicking Measurements, page 58). The ordinary skilled artisan would have been motivated to utilize the sintered mesh material for the wick, as suggested by Pivovar, because such a material may be “able to continuous increase CHF…much thicker coatings…should provide massive CHF enhancement,” pages 58-59. Moreover, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to have tried a sintered mesh material for the wick, since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice.
Claims 8 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Sterbentz in view of Petroski (US 2014/0185734).
Regarding claim 8, Sterbentz anticipates all the elements of the parent claim but does not explicitly disclose wherein the primary coolant is in direct contact with an inner surface of the fuel body.
Petroski does. Petroski is also in the art area of fuel elements for nuclear reactors and teaches (fig. 1b) wherein the fuel (14) may be in direct contact with the coolant (in space 15). Petroski further teaches, as shown in fig. 1b, that it may be beneficial to utilize both areas of direct contact and areas of indirect contact between the fuel and the coolant. The ordinary skilled artisan would have been motivated to utilize the direct contact between the fuel and the coolant in order to enhance the thermal transfer from the hot fuel to the cooler coolant, in particular if a material is used for the coolant (as described by Petroski in ¶ 29) and/or the fuel has anti-corrosion properties. The skilled artisan is aware that a tradeoff must be made between corrosion concerns and heat transfer efficacy.
Regarding claim 15, Sterbentz anticipates all the elements of the parent claim including the quadrilateral shape, as cited above, but does not explicitly disclose wherein it is skewed.
Petroski does. Petroski is also in the art area of fuel elements for nuclear reactors and teaches a fuel wall that may have a skewed quadrilateral (“For example, the structure described herein may have a cross-sectional area having a shape including (or of) a polygon having a plurality of sides (or edges), a circle, or an irregular shape. A polygon may be a triangle, square, rectangle…,” ¶ 40). It would have been an obvious matter of design choice to have utilized an irregular rectangle, such as suggested by Petroski, since such a modification would have involved a mere change in shape of a component. A change in shape is generally recognized as being within the level of ordinary skill in the art. The ordinary skilled artisan is motivated to experiment with fuel and fuel wall shapes in order to influence the coolant flow around the fuel and its outer walls.
Claim 24 is rejected under 35 U.S.C. 103 as being unpatentable over Sterbentz.
Regarding claim 24, Sterbentz anticipates all the elements of the parent claim and further discloses the uranium-based fissionable fuel composition that may include “low-enriched uranium…other fissile fuels and enrichments,” ¶ 43) but does not explicitly disclose an enrichment greater than 5%.
It would have been obvious to one having ordinary skill in the art before the filing date of the invention was made to utilize a higher enrichment since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. As is known in the art, higher enrichments provide better fuel burnup but are generally legally difficult to obtain except for research and test reactors due to nuclear nonproliferation concerns.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LILY C GARNER whose telephone number is (571)272-9587. The examiner can normally be reached 9-5 CT.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jack Keith can be reached at (571) 272-6878. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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LILY CRABTREE GARNER
Primary Examiner
Art Unit 3646
/LILY C GARNER/Primary Examiner, Art Unit 3646
1 see attached and highlighted 132-page Master’s Thesis, pages 55–59.
2 CHF is “critical heat flux,” a term of the art.