Prosecution Insights
Last updated: April 19, 2026
Application No. 17/845,385

SYSTEM AND METHOD FOR MAKING NUCLEAR FUEL ELEMENTS WITH A CONTROLLED NUMBER OF NUCLEAR PARTICLES

Final Rejection §103§112
Filed
Jun 21, 2022
Examiner
WASIL, DANIEL D
Art Unit
3646
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
X-Energy LLC
OA Round
2 (Final)
80%
Grant Probability
Favorable
3-4
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

§103 §112
DETAILED ACTION Response to Amendment A Reply was filed 3 November 2025. All amendments therein have been entered. Claims 1-21 are pending. Claims 1-12, 16, and 20 are withdrawn. Thus, claims 13-15, 17-19, and 21 are further 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. Claim Rejections - 35 USC § 112(b) Claims 13-15, 17-19, and 21 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 regards as the invention. Claim 13 The phrase “stop the conveyer after receiving the first signal from the control circuit, and stop the conveyer after receiving the first signal from the control circuit;” is unclear and confusing. As best understood, the phrase is missing subject matter. Thus, it appears that the claim is incomplete. The claim also appears to be incomplete for omitting structural cooperative relationships of elements. For example, it is unclear which component of the recited system relates to the phrase “producing a nuclear fuel element having a known amount of homogeneously distributed nuclear material”. Since the phrase isn’t linked to any recited component, it’s purpose unclear. It is unclear whether the vibrating mold is configured to homogeneously distribute the target number of the optionally coated nuclear fuel kernel within a particulate matrix material during production of a nuclear fuel element having a known amount of homogeneously distributed nuclear material. Claim 17 The phrase “and count the the optionally coated nuclear fuel kernels” is unclear and confusing. As best understood, the phrase is missing subject matter. Thus, it appears that the claim is incomplete. The claim also appears to be incomplete for omitting structural cooperative relationships of elements. For example, it is unclear which component of the recited system relates to the phrase “producing a nuclear fuel element having a known amount of homogeneously distributed nuclear material”. Since the phrase isn’t linked to any recited component, it’s purpose unclear. It is unclear whether a mold is configured to homogeneously distribute the target number of the optionally coated nuclear fuel kernel within a particulate matrix material during production of a nuclear fuel element having a known amount of homogeneously distributed nuclear material. Claim 18 The phrase “a camera positioned at the exit from the channel” is unclear. Claim 13 states that the channel has an exit. That is, the exit is a part of the channel. Hence, the claim 13 phrase wording “the exit from the channel” conflicts with claim 13. It is unclear whether the phrase should be interpreted as “a camera positioned at the exit of the channel”. Claim 21 The phrase “the solid matrix material” lacks proper antecedent basis. 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 Interpretation It is noted that “nuclear fuel kernels” are not positively recited in the apparatus claims. Rather, the recited system structure is merely capable of being used with “nuclear fuel kernels”. Furthermore, no specific dimensions of a “kernel” are being recited. Thus, the recited system structure can also be used with particles, pellets, etc. Likewise, “particulate matrix material” is not positively recited in the apparatus claims. Claim Rejections - 35 USC § 103 Claims 13-15, 17, and 19, as best understood, are rejected under 35 U.S.C. 103 as being unpatentable over Puliga (US 9,174,364) in combination with King (US 4,468,163), Williams (US 3,773,867), and Bailey (US 6,639,961). Independent claims 13 and 17 are each directed to a combination of known elements As shown in more detail hereafter, these claimed combinations are no more than “the predictable use of prior art elements according to their established functions". Note KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007). Puliga discloses a system comprising a counting device (20) that uses a light beam (21) in counting particles (1) as they free-fall from the exit (30a) of a channel. The counting device (20) generates a counting signal which is sent to control means (control circuit). The control means (via a signal) stops operation of a conveyor (3) when a counted target number of particles reach a pre-established amount. A passage (4, 41) is configured to convey particles from the exit (30a) to a mold (44). Puliga appears to be silent with regard to use of a motor. However, employing a motor to drive a conveyer is conventional in the art. For example, King (previously cited) shows using a motor (16) to drive a conveyer (13). Modification of Puliga to have conventionally included a motor to drive the conveyer, as suggested by King, would have been obvious to one of ordinary skill in the art. Puliga appears to be silent with regard to use of a vibrating mold. However, employing a vibrating mold to homogeneously mix different material is conventional in the art. For example, Williams uses a vibrating mold to homogeneously mix different material. For example, Williams mixes nuclear fuel particles with particulate matrix material. Particularly note Williams at the abstract; col. 1, lines 24-29; col.2, lines 19 and 49-52; and col. 3, lines 9-10. Modification of Puliga’s system to have included a vibrating mold to homogeneously mix different material, as suggested by Williams, would have been obvious to one of ordinary skill in the art. As noted above, “nuclear fuel kernels” are not positively recited. Thus, the examiner asserts that Puliga’s system is structurally capable of being used with “nuclear fuel kernels”, especially since no specific dimensions of a kernel are recited. As a result, the above applied combination of references meets the recited structure of at least claims 13 and 17. Nevertheless, if necessary, use of Puliga’s system with nuclear fuel kernels (and many other different particles) is within the skill of the artisan. For example, Bailey (previously cited) discloses a system similar to Puliga’s system. Bailey discloses a conveyer (26) configured to transmit nuclear fuel particles (e.g., kernels) along a channel. An optical counter (24) counts the particles. The counter transmits a signal when a target number of particles are counted. The conveyer is stopped in response to the signal. Thus, modification of Puliga’s system to have employed particles that comprise nuclear fuel kernels, as suggested by Bailey, 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. Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over Puliga in combination with King, Williams, and Bailey as applied to claim 13 above, and further in view of Ahmed ("Innovative Low-Cost Approaches to Automating QA/QC of Fuel Particle Production Using On-Line Nondestructive Methods for Higher Reliability”, Nuclear Energy Research Initiative Project No. 02-103 (2006)). Ahmed shows that it is well known in the art to use a camera in counting nuclear fuel particles. Further modification of Puliga’s system to have conventionally included a camera in counting the particles, as suggested by Ahmed, would have been obvious to one of ordinary skill in the art. Response to Arguments Applicant’s arguments have been fully considered. Most arguments are answered above. Applicant’s arguments concerning the prior art rejections are moot because the new ground of art rejections do not rely on the combination of references applied in the prior Office Action. Allowable Subject Matter Claim 21 would be allowable if rewritten to overcome the rejections under 35 U.S.C. 112(b) (which also concern claim 17 subject matter) set forth in this Office action and to include all of the limitations of the base claim and any intervening claims. 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 nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event will the statutory period for reply expire later than SIX MONTHS from the mailing 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 and/or the specification. 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). 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
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Prosecution Timeline

Jun 21, 2022
Application Filed
Dec 13, 2024
Response after Non-Final Action
Jun 28, 2025
Non-Final Rejection — §103, §112
Nov 03, 2025
Response Filed
Nov 24, 2025
Final Rejection — §103, §112
Feb 17, 2026
Applicant Interview (Telephonic)
Feb 17, 2026
Examiner Interview Summary

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Prosecution Projections

3-4
Expected OA Rounds
80%
Grant Probability
99%
With Interview (+25.1%)
3y 1m
Median Time to Grant
Moderate
PTA Risk
Based on 656 resolved cases by this examiner. Grant probability derived from career allow rate.

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