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4624827 Nuclear reactor control rod having a reduced worth tip
Ann. Nucl. Energy, Vol. 14, No. 4, pp. V-VI, 1987 Pergamon Journals Ltd. Printed in Great Britain
NEW
PATENTS
This Section contains abstracts (without graphics) of recently issued United States patents and published patent applications filed from over 30 countries under the Patent Cooperation Treaty. This information was obtained from recent additions to the Pergamon PATSEARCH ~ online database in accordance with interest profiles developed by the Editors. Further information about Pergamon PATSEARCH ~ can be obtained from Pergamon InfoLine Inc., 1340 Old Chain Bridge Road, McLean, Virginia 22101 U.S.A. Copies of complete patents announced in this Section are available from Pergamon InfoLine Inc. for $8 per copy. Payment with order is required. Orders outside North America add $2 for air postage. Order by patent number for Pergamon InfoLine only.
4624827
4627955
NUCLEAR REACTOR CONTROL ROD HAVING A REDUCED W O R T H TIP
PROCESS FOR DETECTING THE VARIATIONS IN THE REACTIVITY OF THE CORE OF A PRESSURIZED WATER NUCLEAR REACTOR AND DEVICE FOR MAKING USE OF THIS PROCESS
Pratap Doshi, John Wilson Westinghouse Electric Corp
assigned
to
A control rod with a reduced worth tip is provided for a nuclear reactor which includes an elongated tubular cladding with its opposite ends closed and having a plurality of pellets of two different types disposed in its lower end portion in an end-to-end relationship. One type of pellets is formed of a neutron absorbing material, such as B4C, whereas, the other type of pellets is formed of an inert material, such as ZrO2. The absorber pellets and the inert pellets are interspaced between one another in the lower end of the rod so as to gradually reduce the rate of change of the neutron flux experienced at the rod's lower end portion as it moves in and out of the fuel assembly to thereby alleviate pellet-cladinteraction and thus reduce the likelihood of fuel rod failure. In one embodiment, the axial heights of the absorber pellets progressively increase from the bottom to the top of the rod's lower end portion while the axial heights of the interspaced inert pellets remain constant. In a second embodiment, the axial heights of the inert pellets progressively decrease from the bottom to the top of the rod's lower end portion while the axial heights of the interspaced absorber pellets remain constant.
Jean Leroy, Pierre Ruiz, Gif Sur Yvette, France assigned to Framatome & Cie Process and device for the detection of the variations, due to a fault in the position of the core control clusters, in the reactivity of the core of a reactor. A momentary value (6) representing the reactivity calculated directly from the core neutron power (2) is compared to a momentary value (30) representing the reactivity calculated from the momentary mean temperature (25) in the core and the mean boron concentration (29) in the primary fluid passing through the core. The invention applies to pressurized water nuclear reactors.
4629600 METHOD AND APPARATUS FOR MEASURING URANIUM ISOTOPE ENRICHMENT Nobuhar Ishiguro, Akira Yokohama, Japan assigned to Kakunenryo Kaihatsu Jigyodan
Kurosawa, Doryokuro
NEW
PATENTS
This Section contains abstracts (without graphics) of recently issued United States patents and published patent applications filed from over 30 countries under the Patent Cooperation Treaty. This information was obtained from recent additions to the Pergamon PATSEARCH ~ online database in accordance with interest profiles developed by the Editors. Further information about Pergamon PATSEARCH ~ can be obtained from Pergamon InfoLine Inc., 1340 Old Chain Bridge Road, McLean, Virginia 22101 U.S.A. Copies of complete patents announced in this Section are available from Pergamon InfoLine Inc. for $8 per copy. Payment with order is required. Orders outside North America add $2 for air postage. Order by patent number for Pergamon InfoLine only.
4624827
4627955
NUCLEAR REACTOR CONTROL ROD HAVING A REDUCED W O R T H TIP
PROCESS FOR DETECTING THE VARIATIONS IN THE REACTIVITY OF THE CORE OF A PRESSURIZED WATER NUCLEAR REACTOR AND DEVICE FOR MAKING USE OF THIS PROCESS
Pratap Doshi, John Wilson Westinghouse Electric Corp
assigned
to
A control rod with a reduced worth tip is provided for a nuclear reactor which includes an elongated tubular cladding with its opposite ends closed and having a plurality of pellets of two different types disposed in its lower end portion in an end-to-end relationship. One type of pellets is formed of a neutron absorbing material, such as B4C, whereas, the other type of pellets is formed of an inert material, such as ZrO2. The absorber pellets and the inert pellets are interspaced between one another in the lower end of the rod so as to gradually reduce the rate of change of the neutron flux experienced at the rod's lower end portion as it moves in and out of the fuel assembly to thereby alleviate pellet-cladinteraction and thus reduce the likelihood of fuel rod failure. In one embodiment, the axial heights of the absorber pellets progressively increase from the bottom to the top of the rod's lower end portion while the axial heights of the interspaced inert pellets remain constant. In a second embodiment, the axial heights of the inert pellets progressively decrease from the bottom to the top of the rod's lower end portion while the axial heights of the interspaced absorber pellets remain constant.
Jean Leroy, Pierre Ruiz, Gif Sur Yvette, France assigned to Framatome & Cie Process and device for the detection of the variations, due to a fault in the position of the core control clusters, in the reactivity of the core of a reactor. A momentary value (6) representing the reactivity calculated directly from the core neutron power (2) is compared to a momentary value (30) representing the reactivity calculated from the momentary mean temperature (25) in the core and the mean boron concentration (29) in the primary fluid passing through the core. The invention applies to pressurized water nuclear reactors.
4629600 METHOD AND APPARATUS FOR MEASURING URANIUM ISOTOPE ENRICHMENT Nobuhar Ishiguro, Akira Yokohama, Japan assigned to Kakunenryo Kaihatsu Jigyodan
Kurosawa, Doryokuro