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 .
Status of Claims
1. Claims 1-5, 22-24, 27-28, and 31 are pending in this application. Claim 27 is withdrawn. Claims 1-5, 22-24, 28, and 31 are examined herein.
Response to Arguments
2. Applicant's arguments filed 02/09/26 have been fully considered but they are not persuasive.
3. Regarding the drawing objections and the rejection under 35 U.S.C 112(a) as lacking an adequate written description, the examiner does not find the arguments persuasive. Figs. 1-5 are fuel bundles for a heavy water reactor. The disclosure states that fuel bundles with added emphasis “can instead have a square or rectangular geometry such as those that would be used with a non-CANDU reactor such as a light water reactor having nxn fuel elements.” The specification does not include any description whatsoever as to the relative disposition of fuel elements in a fuel bundle having “square or rectangular geometry” and comprising “nxn fuel elements.” It is noted that fuel bundles for light water reactors having square geometry and nxn fuel elements have drastically different fuel element arrangements than that which is illustrated for the heavy water reactor fuel bundles of the disclosure. A representative sampling of disclosures depicting light water reactor fuel assemblies containing burnable poison-containing fuel rods is shown below.1 There is no portion of the disclosure that would suggest to a skilled artisan that the inventors were in possession of such an invention at the time the disclosure was filed. The rejections are maintained.
PNG
media_image1.png
250
722
media_image1.png
Greyscale
4. The remainder of Applicants arguments are directed to amended claim language and are therefore addressed in the rejections below.
5. Applicant is reminded that the functional language present in the claims is merely a consequence provided by the structure of nuclear fuel containing burnable poison material. Any prior art that contains the structural limitation of a nuclear fuel containing two different burnable poisons will meet the functional limitations recited in the claims. The examiner has provided a detailed explanation of this multiple times throughout prosecution of this application. Applicant has further failed to demonstrate unexpected results. The result of “ the reactivity decay rate decreasing even after the Gd is consumed leading to extending the life of the fuel and improving the bundle exit burnup” is, in fact, predicted by the prior art. Because different neutron poison nuclei have different cross-sections for neutron capture, the reactivity of a core containing neutron poisons will first be influenced more by the neutron poison having the higher cross-section for neutron capture. As this poison is consumed by neutron capture reactions, the poison having the lower cross-section for neutron capture will increasingly contribute to the reactivity of the core. See Alsop at columns 1-2. It is noted that the purported unexpected results are not commensurate in scope with the presently claimed invention, which is a fuel bundle for a light water reactor.
Drawings
6. The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the fuel bundle for a light water moderated nuclear reactor (claims 1-3, 31) must be shown or the feature(s) canceled from the claim(s). No new matter should be entered.
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.
Claim Rejections - 35 USC § 112
7. The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
8. Claims 1-5, 22-24, 28, and 31 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for pre-AIA the inventor(s), at the time the application was filed, had possession of the claimed invention.
Further, regarding claims 1, 2, 3, and 31, the specification as filed does not disclose any details of the relative positioning of fuel rods in light water reactor fuel bundle or any details of fuel elements other than the burnable poison containing element. The disclosure states only that the fuel bundle is “square or rectangular” and has “nxn fuel elements” ([0020]). Thus, the limitations “a plurality of fuel elements disposed in an inner portion and an outer portion of the fuel bundle; wherein at least one first fuel element is disposed in the inner portion, wherein fuel elements disposed in the outer portion of the fuel bundle are substantially free of the at least two different neutron absorbers and contain the at least one fissile material, wherein at least one second fuel element containing a second fissile material is disposed in the outer portion of the fuel bundle, wherein the at least one second fuel element is a plurality of second fuel elements and wherein one of the at least one first fuel element is positioned at a centre of the fuel bundle” recited in claims 1-3 and 31 are new matter.
Background Information
10. The neutron cross-section of a nucleus is a measure of how likely the nucleus is to interact with a neutron. A nucleus with a higher cross-section is more likely to react with a neutron than a nucleus with a lower cross-section.2
11. The neutron cross-sections of the elements are well-known.3
Boron: 760
Gd: 49000
Dy: 950
Hf: 104
Er: 165
Eu: 4570
Claim Rejections - 35 USC § 103
12. 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.
13. For applicant's benefit, the portions of the reference(s) relied upon in the below rejections have been cited to aid in the review of the rejections. While every attempt has been made to be thorough and consistent within the rejection, it is noted that prior art must be considered in its entirety, including disclosures that teach away from the claims. See MPEP 2141.02 VI.
14. 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.
15. Claims 1, 4-5, 22-24, 28 are rejected under 35 U.S.C. 103 as being unpatentable over Morimoto et al., US 4,789,520 in view of Alsop US 4,671, 927, in further view of Aoyama et al., US 5,537,337.
16. Regarding claim 1, Morimoto discloses a fuel bundle for a light water moderated nuclear reactor (Figs. 9&10, column 1, lines 5-9), the fuel bundle comprising a plurality of fuel elements (15) disposed in an inner portion and an outer portion of the fuel bundle; wherein at least one first fuel element (15B) is disposed in the inner portion; the at least one first fuel element containing U-235 (column 4, lines 15-40) and containing the neutron absorber Gd (column 6, lines 22-32), wherein fuel elements disposed in the outer portion of the fuel bundle (15A) are substantially free of neutron absorbers and contain the at least one fissile material (column 4, lines 15-40; column 6, lines 29-31. Morimoto does not disclose that the fuel element contains at least two different neutron absorbers.
Alsop teaches a fuel element for a light water nuclear reactor comprising U-235 (column 3, lines 47-48) enriched to 3% (column 4, lines 35-36) and containing at least two different neutron absorbers (column 3, lines 51-54), wherein the at least one fissile material and the at least two different neutron absorbers are homogeneously mixed in fuel meat of the fuel element to have a generally even distribution of the at least one fissile material and the at least two neutron absorbers throughout the fuel meat of the element, wherein the at least one fissile material and the at least two different neutron absorbers are in direct contact with the fuel meat (column 3, lines 54-56; column 1, lines 61-62)
wherein a first neutron absorber of the at least two different neutron absorbers has a first depletion characteristic that provides neutron absorption during burnup of the fuel element, and wherein a second neutron absorber of the at least two different neutron absorbers has a second depletion characteristic different from the first depletion characteristic and that provides neutron absorption over a longer term than that of the first neutron absorber;
wherein the first neutron absorber provides a first neutron reactivity defined by the first depletion characteristic,
wherein an amount of the first neutron absorber and the second neutron absorber provides a second neutron reactivity defined by the second depletion characteristic and an amount of the second neutron absorber,
wherein, when burned in a nuclear reactor, the fuel element provides a reduced rate of reactivity decay and an extended fuel discharge burnup relative to a comparable fuel element having a single neutron absorber and the same fissile material and wt% of neutron absorber as the fuel element (Gd has a much higher neutron cross-section than boron; column 2, lines 9-15; column 4, lines 29-66),
and wherein the fuel element comprises 1.02-21 wt% of the at least two different homogeneously mixed neutron absorbers in a fresh state (column 3, line 63; column 4, line 4; claims 2-4), which overlaps the claimed range. However, Alsop establishes that the amount of poison in the fuel is a result-effective variable (see at least Fig. 2 and column 2, lines 9-68). Therefore, one of ordinary skill in the art at the time of invention/filing would have been motivated to determine optimal or workable amounts of the poisons by routine experimentation to achieve a desired “reactor power distribution” (column 2, lines 65-66) or “burn-out rate” (column 4, lines 67-68).
One of ordinary skill in the art at the time of invention/filing would have found it obvious to employ the fuel element taught by Alsop in the fuel assembly of Morimoto for the predictable advantages of improving nuclear reactor power distribution (column 2, lines 64-69) and reducing residual penalty (column 5, lines 1-21).
Alsop teaches a mixture of gadolinium with boron for its hybrid burnable absorber-nuclear fuel composition. Aoyama teaches that the combinations of burnable absorbers Gd/Er and Gd/Dy are equivalent to Gd/B (column 6, lines 36-44). Moreover, a skilled artisan would recognize that B, Dy, Er, and Hf have similar neutron cross-sections (see “Background Information” section above), making them equivalent neutron poisons. Thus, one of ordinary skill in the art at the time of invention/filing would have been motivated to substitute Dy, Er, or Hf for B in the hybrid burnable absorber-nuclear fuel composition of Alsop in the fuel assembly of Morimoto.
17. Regarding claims 4 and 5, the modification of Morimoto as taught by Alsop and Aoyama makes claim 1 obvious. Morimoto further discloses a fuel bundle comprising 6 wt % U-235 (column 7, line 8-10).
18. Regarding claims 22-24, the modification of Morimoto as taught by Alsop and Aoyama makes claim 1 obvious. Alsop further teaches a fuel element having a reduced reactivity when initially fed into the reactor relative to a comparable fuel bundle comprising a comparable fuel element having a single neutron absorber and the same fissile material and wt% of neutron absorber as the at least one first fuel element, wherein the fuel depletion period of the at least one first fuel element is longer than a comparable fuel bundle comprising a comparable fuel element having a single neutron absorber and the same fissile material and wt% of neutron absorber as the at least one first fuel element, and wherein the amounts of the at least two different neutron absorbers provide more reactivity of the fuel during a second phase of the fuel depletion period than a comparable fuel element having a single neutron absorber and the same fissile material and wt% of neutron absorber as the at least one first fuel element, and wherein the first phase ends and the second phase begins at or before around mid-burnup, wherein the amount of the first neutron absorber is configured to be substantially exhausted by around mid-burnup ((Gd has a much higher neutron cross-section than boron; column 2, lines 9-15; column 4, lines 29-66 ). One of ordinary skill in the art at the time of invention/filing would have been motivated to employ the fuel element of Alsop in the fuel assembly of Morimoto for the reasons stated above.
19. Claim 28 is rejected under 35 U.S.C. 103 as being unpatentable over Morimoto et al., US 4,789,520 in view of Alsop US 4,671, 927 and Aoyama et al., US 5,337,337, as evidenced by Mogard, US 4,004,972.
20. Regarding claim 28, the modification of Morimoto as taught by Alsop and Aoyama makes claim 1 obvious. Alsop teaches a fuel element comprising a zirconium alloy cladding (column 3, lines 31-34). Mogard establishes that fuel rod claddings made of zirconium alloys (column 4, lines 31-32) are collapsible under the high-pressure conditions of an operating nuclear reactor (see column 2, lines 65-68). Thus the fuel rod of Alsop also possesses this characteristic. One of ordinary skill in the art at the time of invention/filing would have been motivated to employ the fuel element of Alsop in the fuel assembly of Morimoto for the reasons stated above.
Interviews
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.
Additional References
The attached Notice of Reference Cited (PTO-892) cites additional prior art made of record and not relied upon that is considered pertinent to applicant's disclosure.
Finality
THIS ACTION IS MADE FINAL. 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.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SHARON M DAVIS whose telephone number is (571)272-6882. The examiner can normally be reached Monday - Thursday, 7:00 - 5:00 pm ET.
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.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/SHARON M DAVIS/Primary Examiner, Art Unit 3646
1 Figures taken from art cited on the PTO-892 form dated 04/26/26 and the PTO-892 attached herewith.
2 “Neutron Cross-section” attached previously.
3 Values here are from periodic table.com (https://periodictable.com/Properties/A/NeutronCrossSection.html)
Prosecution Insights