Prosecution Insights
Last updated: April 19, 2026
Application No. 18/623,667

HEAT PIPE HAVING A WICK BETWEEN CONCENTRIC INNER AND OUTER HOUSINGS, FOR USE IN HEAT REMOVAL FROM A NUCLEAR REACTOR CORE

Non-Final OA §102§103§112
Filed
Apr 01, 2024
Examiner
WASIL, DANIEL D
Art Unit
3646
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Westinghouse Electric Company LLC
OA Round
1 (Non-Final)
80%
Grant Probability
Favorable
1-2
OA Rounds
3y 1m
To Grant
99%
With Interview

Examiner Intelligence

Grants 80% — above average
80%
Career Allow Rate
524 granted / 656 resolved
+27.9% vs TC avg
Strong +25% interview lift
Without
With
+25.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
36 currently pending
Career history
692
Total Applications
across all art units

Statute-Specific Performance

§101
4.7%
-35.3% vs TC avg
§103
34.6%
-5.4% vs TC avg
§102
19.7%
-20.3% vs TC avg
§112
38.0%
-2.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 656 resolved cases

Office Action

§102 §103 §112
DETAILED ACTION Notice of AIA Status This application is examined under the first inventor to file provisions of the AIA . Claims 1-20 are pending. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. Claims 1-9, 11, and 18-20 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 an inventor regards as the invention. Claims 1 and 18 The phrase “the heat pipe adjacent to a heat exchanger” is unclear. The phrase lacks proper antecedent basis. It is also unclear whether a heat exchanger is being positively recited. Claim 2 The phrase “a cladding defining configured about” is unclear. At least one word appears to be missing in said phrase. Thus, the claim appears to be incomplete. Claims 6-8 Claim 1 recites an ”inner volume configured to accommodate a heat source”. Thus, as best understood, a “heat source” is not positively recited. It follows that it is unclear how additional description of the (non-recited) heat source in claims 6-8 further limits the heat pipe structure. Claim 11 It is unclear what constitutes a “core block material”. It is unclear whether the “core” is a nuclear reactor core. Regardless, it would appear that any material in a nuclear reactor core would be structurally capable of blocking a fluid, and thus constitute a “core block material”. It is unclear whether the core block material is a solid heat transfer media (e.g., a graphite block) in a nuclear reactor core. It is unclear whether the heat pipe is located in this solid heat transfer media. Claim 18 The phrase “a cladding defining configured about” is unclear. At least one word appears to be missing in said phrase. Thus, the claim appears to be incomplete. The phrase “the cladding defines a a second intermediate volume” is unclear. At least one word appears to be missing in said phrase. Thus, the claim appears to be incomplete. Review The claims do not allow the public to be sufficiently informed of what would constitute infringement. Any claim not specifically addressed is rejected based upon its dependency. Claim Rejections - 35 USC § 102 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, 9-14, and 16-20, as best understood, are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Fiebelmann (US 3,414,475). Claims 1, 10, and 18-20 Fiebelmann (cited via IDS) teaches a heat pipe that is structurally configured to remove heat from a nuclear reactor core. The heat pipe comprises an inner housing (9), an outer housing (1), a wick (3, 5), and a working fluid. The inner housing (9) has an outer surface. The inner housing defines an inner volume (12, 13) configured to accommodate a heat source (2, 33), which may be a nuclear fuel element. The outer housing (1) has an inner surface. The outer housing (1) is configured about the inner housing (9) and the heat source (2). The wick (e.g., capillary liner 3 together with a capillary condensate return structure 5) is positioned between the inner housing (9) and the outer housing (1). The wick extends along at least a portion of the length of the heat pipe. The wick comprises a capillary material (e.g., capillary liner 3, capillary condensate return structure 5). The wick is configured to contact at least a portion of the outer surface of the inner housing (e.g., lower part of capillary liner 3 contacts inner housing 9). The wick is configured to contact at least a portion of the inner surface of the outer housing (e.g., upper part of capillary condensate return structure 5 contacts outer housing 1). The wick defines an intermediate volume between the inner housing and the outer housing. The working fluid (col. 1, lines 14-38) is within the intermediate volume. The working fluid is configured to evaporate at a first end of the heat pipe and condense at a second end of the heat pipe (col. 1, lines 14-38; Figure 1) adjacent to a heat exchanger. It is noted that (as best understood) a heat exchanger does not appear to be positively recited as a part of the heat pipe. The wick (3, 5) is configured to return working fluid that has condensed at the second end to the first end (col. 1, lines 14-38; col. 2 line 41 - col. 3 line 68). Evaporation and condensation of the working fluid is able to transfer heat from the first end to the second end for dissipation (col. 1, lines 14-38; col. 2 line 41 - col. 3 line 68) via a heat exchanger. Claims 3-4 and 12-13 Fiebelmann teaches a plurality of ribs (e.g., 32) (e.g., Figure 6). Claims 5 and 14 Fiebelmann teaches an endcap (23 top) coupled to the second end (Figure 3). Fiebelmann also teaches another endcap (6) coupled to the second end (e.g., Figure 1). Claim 7 Fiebelmann teaches using nuclear fuel as the heat source (e.g., col. 2, lines 56-57; col. 5, lines 28-31). Claim 9 and 16 Fiebelmann teaches a working fluid reservoir (12). Claim 11 Fiebelmann has material in a nuclear reactor core that is structurally capable of blocking a fluid. Note the above rejection under 35 U.S.C. 112(b). Claim 17 The heat pipe of Figure 1 in Fiebelmann includes structure that acts as a thermosiphon. Claim Rejections - 35 USC § 103 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, 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. Claims 2, 6, 8, and 15, as best understood, are rejected under 35 U.S.C. 103 as being unpatentable over Fiebelmann (US 3,414,475) as applied to claim 1 above, and further in view of Johnson (US 8,000,431) and Loginov (US 2021/0335510). Johnson (cited via IDS) shows that it is well known in the art to mix a moderator (26) with nuclear fuel (e.g., 24; uranium) to enhance neutron moderation. Modification of Fiebelmann to have included a moderator mixed with the fuel to enhance neutron moderation, as suggested by Johnson, would have been obvious to one of ordinary skill in the art. With said modification, Fiebelmann’s heat source includes a moderator. Loginov (cited via IDS) discloses having nuclear fuel (8) in a cladding (1, 3) positioned about the outer housing (2) of a heat pipe. The arrangement allows for additional heat generation due to more nuclear reactions. Further modification of Fiebelmann to have included additional nuclear fuel outside of the heat pipe to have generated more heat, as suggested by Loginov, would have been obvious to one of ordinary skill in the art. The result of the modifications would have been predictable to the skilled artisan. Objections to the 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 or the feature(s) must be canceled from the claim(s). No new matter should be entered. The following recited features is not shown: ribs extend from center point of inner housing (claims 4 and 13) reservoir (claim 9) thermosiphon (claim 17) The drawings are further objected to because: The arrows to the inner housing (104) and the outer surface (106) do not accurately point to these features. For example, Figure 1 shows the outer surface (106) being located radially interior of the inner housing (104). It appears that reference numerals 104 and 106 should be swapped in Figure 1. Correction is required. 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. The Applied References For Applicant’s benefit, portions of the applied reference(s) have been cited (as examples) 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 by Applicant, including any disclosures that may teach away from the claims. See MPEP 2141.02 (VI). Application Status Information Applicants seeking status information regarding an application should check Patent Center on the Office website at www.uspto.gov/PatentCenter. Alternatively, the requester may contact the Application Assistance Unit (AAU). See MPEP § 1730, subsection VI.C. See MPEP § 102 for additional information on status information. For a USPTO Customer Service Representative call 800-786-9199 or 571-272-1000. 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 Daniel Wasil can be reached at (571) 272-4654, on Monday-Thursday from 10:00-4:00 EST. Supervisor Jack Keith (SPE) can be reached at (571) 272-6878. /DANIEL WASIL/ Examiner, Art Unit 3646 Reg. No. 45,303 /JACK W KEITH/Supervisory Patent Examiner, Art Unit 3646
Read full office action

Prosecution Timeline

Apr 01, 2024
Application Filed
Mar 17, 2026
Non-Final Rejection — §102, §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
80%
Grant Probability
99%
With Interview (+25.1%)
3y 1m
Median Time to Grant
Low
PTA Risk
Based on 656 resolved cases by this examiner. Grant probability derived from career allow rate.

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