# US 12,112,857 B2 · Light water reactor uranium fuel assembly and operation method of nuclear fuel cycle

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- Number: US 12,112,857 B2
- Document ID: US12112857B2
- Status: Granted
- Kind: B2
- Application number: 17/587,315
- Filed: 2022-01-28
- Published: 2022-10-13
- Granted: 2024-10-08
- Earliest claimed: 2021-03-23
- Assignees: Kabushiki Kaisha Toshiba; Toshiba Energy Systems & Solutions Corporation
- Applicants: Kabushiki Kaisha Toshiba; Toshiba Energy Systems & Solutions Corporation
- Inventors: Kouji Hiraiwa; Kenichi Yoshioka; Rei Kimura; Satoshi Wada; Tsukasa Sugita
- Web page: https://patentgrep.com/patent/US12112857B2

## CPC

- G21C 19/32: Apparatus for removing radioactive objects or materials from the reactor discharge area, e.g. to a storage place; Apparatus for handling radioactive objects or materials within a storage place or removing them therefrom (disposal of waste material G21F9/00)
- G21C 19/42: Reprocessing of irradiated fuel
- G21C 19/48: Non-aqueous processes
- G21G 1/02: in nuclear reactors (by thermonuclear reactions G21B; conversion of nuclear fuel G21C)
- G21C 3/326: comprising fuel elements of different composition; comprising, in addition to the fuel elements, other pin-, rod-, or tube-shaped elements, e.g. control rods, grid support rods, fertile rods, poison rods or dummy rods
- Y02E 30/30: Nuclear fission reactors
- G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J)
- G21G: CONVERSION OF CHEMICAL ELEMENTS; RADIOACTIVE SOURCES (applications of radiation in general G21H5/00; handling particles, e.g. neutrons, or electromagnetic radiation not otherwise provided for G21K)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

According to embodiments, a light water reactor uranium fuel assembly is capable of reducing heating values of both Am-241 and Cm-244, to reduce the amount of generated vitrified waste without using fast reactors. The light water reactor uranium fuel assembly is a light water reactor uranium fuel assembly to be used in a nuclear fuel cycle that extracts. An americium isotope is extracted at the time of reprocessing of spent fuel to be added to a fuel, in which a weight fraction W (unit: wt %) of americium 241 to be added to a fuel heavy metal is in ranges of W<−0.006e2+0.12e−0.43 (enrichment: 5 wt % or more), W<−0.000356e+0.00357 (enrichment: 4.2 wt % or more and less than 5.0 wt %) with respect to an average enrichment of uranium 235 e (unit: wt %) of the fuel assembly.

## Claims

### Claim 1

A fresh fuel assembly for a light water reactor, comprising:
a plurality of fuel rods bundled together, including uranium fuel rods and poison rods,
wherein the uranium fuel rods contain fissile uranium and americium reprocessed from spent fuel and do not contain a neutron poison, and
wherein the poison rods contain both uranium and a neutron poison;
wherein each of the uranium fuel rods contains a wt. % of americium-241 that is:
smaller than −0.006e2+0.12e−0.43 when the uranium enrichment e is 5 wt. % or more, and
smaller than −0.000356e+0.00357 when the uranium enrichment is 4.2 wt. % or more and less than 5.0 wt. %.