DETAILED ACTION
Election
Applicant’s election of Invention I without traverse in the Reply filed 24 March 2026 is acknowledged. Claims 1-20 are pending. The elected Invention encompasses claims 1-12. Claims 13-20 are withdrawn from further consideration as being drawn to nonelected Invention(s). The restriction requirement is deemed proper and is therefore made FINAL.
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 1-12 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
The meaning of the term “characterizing” is unclear. For example, it is unclear whether the term means “identifying location of” or something else.
The phrase “bypass pipe” is unclear. For example, it is unclear what component is bypassed by the “bypass pipe”.
The step of “determining an isotopic ratio of 137Cs/134Cs within sodium in the bypass pipe” is unclear. It is unclear whether the “determining” actually occurs in the bypass pipe or in some other component (e.g., a processing cell). Also, it is unclear how the “determining” can occur without a prior step of measuring amounts of 137Cs and 134Cs. Thus, the claim appears to be incomplete for omitting cooperative relationships of steps which allow for the intended result.
The phrase “determining . . . an identification of the failed fuel assembly” is unclear. The meaning of the term “identification” is unclear. The term can be interpreted to mean identifying that a failed fuel assembly exists. The term can also be interpreted to mean identifying a core section where a failed fuel assembly is present. It is unclear whether the term should be interpreted to mean “the location” or something else. Since the claim can be interpreted differently, it is prima facie indefinite.
Claim 4
It is unclear how claim 4 further limits the method of claim 1 . It is unclear whether “a fuel assembly has failed” (claim 4) is the same failed fuel assembly in claim 1 or a different fuel assembly.
Claim 5
It is unclear how claim 5 further limits the method of claim 1. It is unclear how “determining a Xenon isotopic ratio by mass spectroscopy” relates to (is linked to) the method for characterizing a failed fuel assembly. Thus, claim 5 appears to be incomplete.
Claims 6-7
It is unclear how claim 6 further limits the method of claim 1. It is unclear how “providing a tag gas” to fuel element relates to the method for characterizing a failed fuel assembly. Thus, claim 6 appears to be incomplete.
Claims 9-10
The phrase “determining a subset of fuel assemblies” is unclear, especially when the subset can comprise the failed fuel assembly. The claim allows for each fuel assembly in the core to be a “subset”. Thus, it is unclear how claim 9 further limits the method of claim 1.
Claim 11
It is unclear what constitutes a “lift and burp technique”, which appears to be unconventional in the art.
Claim 12
The phrase “isolating the sodium coolant in the bypass pipe” is unclear. For example, it is unclear whether the sodium coolant is isolated inside the bypass pipe, whether the sodium coolant is isolated from the bypass pipe, or something else. Since the claim can be interpreted differently, it is prima facie indefinite.
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.
Initial Comments
It appears that an embodiment of the invention is directed to locating a failed fuel assembly in a reactor core without using a unique tag gas for each respective fuel assembly. This allows for the total number of unique tag gases to be less than the total number of fuel assemblies. For example, a first unique tag gas may be applied to a first group of fuel assemblies, a second unique tag gas may be applied to a second group of fuel assemblies, and so on. The embodiment allows for a two-part technique to be used to locate the failed fuel assembly. First, a tag gas is used to determine that the failed fuel assembly is located in a specific group of fuel assemblies. Second, burnup is used to locate the failed fuel assembly inside this specific group. The burnup is calculated by using a measured isotopic ratio of fission products (e.g., isotopic ratio of 137Cs/134Cs).
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 1-4 and 6-12, as best understood, are rejected under 35 U.S.C. 103 as being unpatentable over Sano (JPH0341396A) in combination with Takahashi (JP2008241510A) and Naitou (JPS59112291A).
Claim 1
Sano (cited via IDS) discloses employing a two-part technique to locate a failed fuel assembly. A tag gas is used to find a specific core section which contains the failed fuel assembly. Then, burnup is used to locate the failed fuel assembly in said specific core section. The burnup can be determined via a measured ratio of (fission product) isotopes (e.g., Kr/Kr). Fission product gases are strongly correlated to unique burnup.
Takahashi (cited via IDS) shows that it is well known in the art that burnup can be determined via measuring (fission product) Cs/Cs isotope ratios (e.g., 137Cs/134Cs). Substitution of one burnup determination method for another substantially equivalent burnup determination method is within the skill of the artisan. In re Williams, 36 F.2d 436, 438 (CCPA 1929). Thus, modification of Sano to have used a burnup determination based on the ratio of 137Cs/134Cs, as suggested by Takahashi, would have been obvious to one of ordinary skill in the art. The result of the modification would have been predictable to the skilled artisan.
Naitou (cited via IDS) shows that it is well known in the art to determine a failed fuel assembly by flowing primary sodium coolant to a bypass pipe (20), and by using 137Cs and 134Cs. Further modification of Sano to have used a bypass pipe in carrying out the determination of a failed fuel assembly, as suggested by Naitou, would have been obvious to one of ordinary skill in the art. The result of the modification would have been predictable to the skilled artisan.
It should be understood, that the combined features of Sano, Takahashi, and Naitou are being applied. Thus, the above combination rejection encompasses (and includes) each individual reference being modified by the other two references.
Claim 2
The combined references disclose conventionally determining an isotopic ratio via gamma spectroscopy. For example, note Naitou at [0001, 0003].
Claim 3
The combined references disclose the method without removing primary sodium coolant from the closed system. For example, note Naitou at Figure 1 and [0001, 0003].
Claim 4
Sano conventionally detects a fission product in the cover gas.
Claims 6-7
Sano conventionally provides a tag gas to fuel elements, where the number of unique tag gases is less than the number of fuel assemblies.
Claim 8
The combined references disclose performing the method during reactor operation. For example, note Naitou.
Claims 9-11
Sano discloses determining a subset of fuel assemblies, and analyzing the subset to determine a failed fuel assembly.
Claim 12
The combined references disclose isolating the sodium coolant in the bypass pipe. For example, note Naitou at Figure 1 and [0001, 0003].
Claim 5, as best understood, is rejected under 35 U.S.C. 103 as being unpatentable over Sano in combination with Takahashi and Naitou as applied to claim 1 above, and further in view of Honekamp (US4080250).
Honekamp (cited via IDS) shows that it is well known to determine a Xenon isotopic ratio by mass spectroscopy in identifying a failed fuel assembly. For example, note Honekamp at col. 2, lines 1-2; col. 4, lines 29-34; and col. 7, lines 28-31. Further modification of Sano to have used a Xenon isotopic ratio by mass spectroscopy, as suggested by Honekamp, would have been obvious to one of ordinary skill in the art.
Objection to the Title
The Title is objected to because it includes unclear wording, as noted above. The following Title is suggested: “Method Of Identifying Location Of A Leaking Fuel Assembly In A Nuclear Reactor Core”.
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
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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
Prosecution Insights