DETAILED ACTION
Response to Amendment
A Reply was filed 2 February 2026. All amendments therein have been entered. Claims 1-10 are pending.
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 1-10 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 1
It is unclear what level of disposing constitutes “densely arrayed”, especially with regard to non-densely arrayed. The dividing boundary between “densely arrayed” and non-densely arrayed is unclear and unknown. The wording “densely arrayed” is a relative wording which renders the claim indefinite. The wording “densely arrayed” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention.
It is unclear which element is associated with the “storing” feature. For example, it is unclear whether the core, fuel assembly, fuel rods, wrapper tube, or something else is associated with the “storing” feature.
The mentions of a core, an inner core, and an outer core is confusing. For example, it is unclear whether the inner core and the outer core are different parts of the fuel in a cladding tube of a fuel rod. Since the claim can be interpreted differently, it is prima facie indefinite.
An inconsistency between the claimed subject matter and the specification renders the scope of the claim uncertain. The claim is directed to a broad “reactor”. Thus, the claim finds support for a generic reactor, which encompasses a chemical reactor, a nuclear reactor, etc. However, the specification appears to only discuss a “nuclear reactor”. Thus, it is uncertain whether the claim is outside the scope of the specification.
Applicant argues that “With regard to ‘fast reactor’ those of skill in the art would understand this term to refer to a nuclear reactor”. The examiner notes that they may be true if the claim was limited to the nuclear reactor art. However, for reasons discussed above, it isn’t. Regardless, if Applicant’s argument involves one skilled in the nuclear reactor art, then Applicant will have no issue reciting a “fast nuclear reactor”.
Claims 3 and 4
The phrase “a sodium plenum configured of the wrapper tube“ remains unclear. As best understood, the phrase appears to be missing words. As a result, the claim appears to be incomplete.
Claim 4
The intended functional phrase “flowing liquid sodium” is unclear. For example, it is unclear when (if ever) flowing sodium is disposed in an upper portion of the fuel rod. It is also unclear when the sodium has to be flowing. For example, it is unclear whether the sodium can flow while it is being originally placed in an upper portion of the fuel rod, but does not have to flow thereafter.
Claims 9-10
The claim is unclear. As the claim is best understood, a “fraction” of a “fuel volume” allows for choosing an amount that makes the neutron infinite multiplication factors equal.
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 § 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 1-2 and 9-10 are rejected under 35 U.S.C. 103 as being unpatentable over Cachera (US 4,372,911) in combination with Sugino (JP 2005-083966A).
Claim 1
Cachera (of record) discloses a fast reactor core comprising an inner core and an outer core. The inner core has hollow fuel of a first hollow diameter. The outer core has hollow fuel of a second hollow diameter, which is smaller than the first hollow diameter. Particularly note col. 6, lines 16-29. The coolant comprises sodium (e.g., col. 5, lines 40-41).
One of ordinary skill in the art would realize that a fast reactor core can be implemented with various fuels and enrichments, necessarily amounting to certain design characteristics obviously more favorable to use of a certain fuels and enrichments in light of the specific reactor design. For example, Sugino (of record) shows that it is well known in the art to have a fast reactor core employ a Pu enrichment of 11 to 13 wt%. Thus, it would have been obvious to one of ordinary skill in the art to have modified Cachera to have implemented the core with a Pu enrichment of 11 to 13 wt% to meet a particular reactor design.
It is well known in the art to employ a fast reactor core with fuel rods having a triangular-pitch. For example, note Sugino at Figure 1. Thus, it would have been obvious to the skilled artisan to have modified Cachera to have employed the core with conventional triangular-pitched fuel rods to meet a particular reactor design.
The result of the modifications would have been predictable to the skilled artisan.
Claim 2
As previously noted, one of ordinary skill in the art would realize that a fast reactor core can be implemented with various fuels and enrichments, necessarily amounting to certain design characteristics obviously more favorable to use of a certain fuels and enrichments in light of the specific reactor design. For example, Sugino shows that it is well known in the art to have a fast reactor core employ fuel that is a metal fuel alloy of U—Pu—Zr. Thus, it would have been obvious to one of ordinary skill in the art to have modified Cachera to have implemented the core with fuel that is a metal fuel alloy of U—Pu—Zr to meet a particular reactor design.
Claims 9-10
Cachera shows it is advantageous to flatten the power distribution (e.g., col. 1, lines 47-48; col. 6, lines 5-9). Sugino also desires to flatten the power distribution.
Claims 3-6 are rejected under 35 U.S.C. 103 as being unpatentable over Cachera in combination with Sugino as applied to claims 1-2 above, and further in view of Fujimura (US 2024/0153652).
Fujimura (cited via IDS) shows that it is well known in the art to have the height of an inner core (31) lower than the height of an outer core (32) in order to keep the void reactivity within a certain range in a fast reactor core (e.g., [0045-0047]; Figure 3), where a sodium plenum is above the core fuel, and where the inner core fuel assembly height is equal to the outer core fuel assembly height. Modification of Cachera to have had the height of the inner core lower than the height of the outer core in order to keep the void reactivity within a certain range, as suggested by Fujimura, would have been obvious to one of ordinary skill in the art.
Claims 7-8 are rejected under 35 U.S.C. 103 as being unpatentable over Cachera in combination with Sugino as applied to claims 1-2 above, and further in view of Fujimura (US 2019/0392957).
Fujimura (cited via IDS) shows that it is well known in the art to have a metal fuel alloy immersed in bonded sodium (e.g., [0045). Modification of Cachera to have had the metal fuel alloy immersed in bonded sodium in order to enhance bonding, as suggested by Fujimura, would have been obvious to one of ordinary skill in the art.
Objection to the Abstract
The Abstract of the disclosure is objected to because it refers to purported merits or speculative applications of the invention (e.g., “adaptability” and “suppressing deterioration”). 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 following Abstract is suggested:
A sodium-cooled fast nuclear reactor core includes an inner core section and an outer core section. The core uses hollow fuel having a Pu enrichment of 11 to 13 wt%. The Pu enrichment is the same in both core sections. The inner core section contains fuel rods containing hollow fuel with a first hollow diameter. The outer core section contains fuel rods containing hollow fuel with a second hollow diameter, which is smaller than the first hollow diameter. The fuel can be a metal fuel alloy of U—Pu—Zr. The total vertical length of the hollow fuel in the inner core section fuel rods can be shorter than the total vertical length of the hollow fuel in the outer core section fuel rods. The core arrangement allows for flattening the power output distribution in the radial direction.
Response to Arguments
Applicant's arguments have been fully considered but they are not persuasive.
Additional Comment
With regard solely to the above 35 U.S.C. 112(b) rejection of claim 1, it is uncertain whether claim 1 was intended to be interpreted as:
A core of a fast reactor,
the core comprising [[a]] at least one fuel assembly [[,]] including fuel rods that are triangular-pitch [[densely]] arrayed within a wrapper tube, and
the core comprising an inner core and an outer core,
the fuel rods storing, within [[a cladding tube]] cladding tubes, hollow fuel in which Pu-enrichment is within a range of 11 to 13 wt %, [[in which]]
wherein the Pu-enrichment of fuels in [[an]] the inner core and [[an]] the outer core [[is]] are the same,
wherein the at least one fuel assembly includes:
a first fuel assembly disposed in the inner core,
[[including]] wherein the first fuel assembly includes a first fuel rod with a first hollow diameter of the hollow fuel; [[, disposed in the inner core,]] and
a second fuel assembly disposed in the outer core,
[[including]] wherein the second fuel assembly includes a second fuel rod with a second hollow diameter of the hollow fuel, [[that is smaller than the first hollow diameter, disposed at the outer core]]
wherein the second hollow diameter is smaller than the first hollow diameter.
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, however, 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