Prosecution Insights
Last updated: April 19, 2026
Application No. 18/531,636

INTERLOCKING FUEL ASSEMBLY STRUCTURE FOR CORE REACTIVITY CONTROL

Non-Final OA §102§112
Filed
Dec 06, 2023
Examiner
WASIL, DANIEL D
Art Unit
3646
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Terrapower 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 §112
DETAILED ACTION Elections Applicant’s election of Invention III, and species A, without traverse in the Reply filed 17 February 2026 is acknowledged. Claims 18-37 are pending. The elected Invention encompasses claims 18-20. Invention III is deemed elected by original presentation. Claims 21-37 are withdrawn from further consideration as being drawn to nonelected Invention(s). The restriction requirement is deemed proper and is therefore made FINAL Only claims 18-20 are further examined herein. Reasons for election by original presentation are presented hereafter. Election by Original Presentation Newly submitted claims 21-37 are directed to an invention that is independent or distinct from the invention (III) originally claimed and elected. There would be a serious search and/or examination burden if restriction were not required. III. Claims 18-20. IV. Claims 21-37. Inventions III and IV are related as subcombinations disclosed as usable together in a single combination. The subcombinations are distinct if they do not overlap in scope and are not obvious variants, and if it is shown that at least one subcombination is separately usable. In the instant case, subcombination III has separate utility without requiring mechanical keying structures formed on faces of a load pad, and utility while inhibiting relative vertical movement between adjacent core assemblies. Subcombination IV has separate utility without inhibiting all relative motion between adjacent core assemblies. See MPEP § 806.05(d). Inventions IV and III are related as combination and subcombination. Inventions in this relationship are distinct if it can be shown that (1) the combination as claimed does not require the particulars of the subcombination as claimed for patentability, and (2) that the subcombination has utility by itself or in other combinations (MPEP § 806.05(c)). In the instant case, the combination as claimed does not require the particulars of the subcombination as claimed because the combination does not have the ability to inhibit all relative motion between adjacent core assemblies. The subcombination has separate utility such as use without requiring mechanical keying structures formed on faces of a load pad. Since Applicant has received an action on the merits for the originally presented (and elected) Invention III, it has been constructively elected by original presentation for prosecution on the merits. Accordingly, claims 21-37 are withdrawn from consideration as being directed to a non-elected invention. See 37 CFR 1.142(b) and MPEP § 821.03. Thus, only claims 18-20 are further examined herein. To preserve a right to petition, the reply to this action must distinctly and specifically point out supposed errors in the restriction requirement. Otherwise, the election shall be treated as a final election without traverse. Traversal must be timely. Failure to timely traverse the requirement will result in the loss of right to petition under 37 CFR 1.144. If claims are subsequently added, Applicant must indicate which of the subsequently added claims are readable upon the elected invention. Should Applicant traverse on the ground that the inventions are not patentably distinct, then Applicant should submit evidence or identify such evidence now of record showing the inventions to be obvious variants or clearly admit on the record that this is the case. In either instance, if the examiner finds one of the inventions unpatentable over the prior art, the evidence or admission may be used in a rejection under 35 U.S.C. 103 of the other invention. 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 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. Claim 18 The wording “core assembly” is unclear. It is unclear what structure constitutes a “core assembly”. For example, it is unclear whether an ”assembly” is a nuclear fuel assembly, an assembly of core structure (e.g., reflector components, moderator components, support structures), or something else. Even if the ”assembly” was a nuclear fuel assembly, then it would read on any grouping of nuclear fuel. This nuclear fuel grouping would include any of: a grouping of fuel rods; a grouping of fuel ducts; a grouping of different fuel assemblies; a grouping of different reactor core fuel regions, etc. Since the wording “core assembly” can be interpreted differently, it is prima facie indefinite. The phrase “to inhibit relative motion” is unclear. As best understood, said phrase means to inhibit all relative motion. Claim 19 is evidence that claim 18 encompasses inhibiting relative vertical movement. Claim 19 The phrase “do not inhibit relative vertical movement of the first core assembly and the second core assembly” is unclear. As best understood, plural core assemblies can conventionally be simultaneously lifted relative to other core structure. Thus, it is unclear how said phrase further limits the system structure of claim 18. It is unclear whether said phrase should be interpreted as “do not inhibit relative vertical movement between the first core assembly and the second core assembly”. 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 18-20, as best understood, are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Cheatham (US 2014/0341331). Cheatham (cited via IDS) teaches a nuclear core restraint system. A first mechanical key comprises a protrusion (224). A second mechanical key comprises a slot (254). Particularly note Figures 13, 14, and 16-17. Claims 18-20, as best understood, are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Paget (US 3,607,643). Paget teaches a nuclear core restraint system. A first mechanical key comprises a protrusion (23; 26). A second mechanical key comprises a slot (24; 96). Claims 18-20, as best understood, are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Erasmus (US 2013/0270460). Erasmus teaches a nuclear core restraint system. A first mechanical key comprises a protrusion (34). A second mechanical key comprises a slot (29). Particularly note [0044]. Objection to the Drawings The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because reference characters "802" and "804" in Figure 9 have both been used to designate the same part. 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. Objection to the Abstract The Abstract of the disclosure is objected to because it is unclear what structure constitutes a “core assembly”, as discussed above in the 35 U.S.C. 112(b) rejection. An Abstract should include that which is new in the art to which the recited invention pertains. Correction is required. See MPEP § 608.01(b). 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. 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

Dec 06, 2023
Application Filed
Mar 21, 2026
Non-Final Rejection — §102, §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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