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Title: MTR-ETR TECHNICAL BRANCHES QUARTERLY REPORT FOR PERIOD ENDING SEPTEMBER 31, 1958

Abstract

6 4 6 8 7 8 6 7 9 6 2 6 G 8 1 6 : 9 5 6 8 4 8 5 MTR while fueled with plutonium. Slight modifications to the reactor control system allowed safe operation despite the lower delayed neutron fraction from plutonium. ETR Technical Assistance. Three major loop experiments scheduled for iusertion in the ETR have bcen inserted in the ETRC to study neutron aux and reactivity effects. An experimental comparison has shown the equivalence of the reactivity of boron cortained in plastic tape and boron in boric aeid for use in the determination of boron in fuel elements. Reactor physics measurements have been made with the same fuel elements and rod positions in both the ETR and ETRC showing that the slightly higher reflector efficiency in the ETRC gives a higher weighting function near the edge of the reactor and a flatter neutron flux distribution than in the ETR. A system has been designed to allow a portion of a chosen shim or safety rod in the ETR to be used as the regulating rod in an on-off servo control. Calculations have been made of the maximum permissible step insertion of reactivity in themore » ETR for a special case. The gamma heat has been measured at the beginning and end of a cycle and the thermal neutron flux has been measured at three times during a cycle to show their variation in the ETR. Reactor Physics and Engineering. Preliminary out-of- pile heat transfer tests have been started in the nucleate boiling region to provide basic heat transfer data in the convective and subcooled boiling regions and in the burnout regions of fuel elements. A program has been developed to study reaction rates between water and metals below and above their melting points to determine potential hazard to water-cooled nuclear reactors. Studies are proceeding to explain the mechanism of radiation damage in construction materials for testing reactors and their experiments. Two plutonium fuel elements have been hydraulically tested satisfactorily prior to the full core loading in the MTR. The gamma decay dose rates from six fuel elements run in the plutonium loading of the MTR have been followed. Irradiations to 60% burnup have been obtained on the samples in the fuel plate irradiation program. The portion of the capsule irradiation program to study the Gas Cooled Power Reactor fuel element that involves long tcrm prototype irradiations has been undertaken. A self-balancing resistivity instrument in thc range of micro-ohms has been developed for detection of resistivity changes in irradiated samples in the MTR hot cell. Experiments performed in the RMF to measure the average poison cross section per fission of fission products have shown that the cross section for Pu- 239 is considerably larger than that for U-235. Reactivity measurements on four Savannah River thorium slugs irradiated in the MTR were studied for the fission product transicnt and the U-233 build-up from Pa-233 dccay. The neutron spectrum of a reactor location has been constructed to fair accuracy from thrce measurements, the thermal flux, the cadmium ratio, and the fast flux. Nuclear Physics. Eta measurements for U-233 from 0.07 to 11 ev are reported. The most probable prompt neutron energies produced by thermal neutron fission of the three isotopes U-233, U-235, and Pu-239 were compared. Simultaneous fission and total cross section measurements are being continued with a view toward further refinements in the multilevel fitting of fission, total and scattering cross sections, and eta measurements of U-233. Total cross seetions of Au, B, Y, Np, and Ir were measured. The half-life of Ta-180 was determined to be greater than 10/sup 11/ years. The crystal spectrometer was« less

Authors:
Publication Date:
Research Org.:
Phillips Petroleum Co. Atomic Energy Div., Idaho Falls, Idaho
OSTI Identifier:
4277479
Report Number(s):
IDO-16505
NSA Number:
NSA-13-011449
DOE Contract Number:  
AT(10-1)-205
Resource Type:
Technical Report
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-59
Country of Publication:
United States
Language:
English
Subject:
REACTORS; BACKGROUND- CHOPPERS- NEUTRON SPECTROMETERS; BOILING- BURNOUT- CONVECTION- HEAT TRANSFER- MOCKUP- NUCLEATE BOILING- REACTORS- TESTING- WATER- ZONES; BORON- BORON OXIDES- ETR- ETRC- FUEL ELEMENTS- IMPURITIES- IN PILE LOOPS- IRRADIATION- NEUTRON FLUX- POLYMERS- QUANTITATIVE ANALYSIS- REACTIVITY- REACTOR CORE- REACTORS- TESTING; BORON- CROSS SECTIONS- ENERGY LEVELS- FISSION- GOLD- IRIDIUM- MEASURED VALUES- NEPTUNIUM- SCATTERING- TOTAL CROSS SECTIONS- YTTRIUM; BUILDING MATERIALS- IN PILE LOOPS- RADIATION EFFECTS- REACTORS- TESTING; BURNUP- CAPSULES- EGCR- FUEL ELEMENTS- IRRADIATION- MATERIALS TESTING-

Citation Formats

McCollom, K.A. ed. MTR-ETR TECHNICAL BRANCHES QUARTERLY REPORT FOR PERIOD ENDING SEPTEMBER 31, 1958. United States: N. p., 1958. Web. doi:10.2172/4277479.
McCollom, K.A. ed. MTR-ETR TECHNICAL BRANCHES QUARTERLY REPORT FOR PERIOD ENDING SEPTEMBER 31, 1958. United States. doi:10.2172/4277479.
McCollom, K.A. ed. Tue . "MTR-ETR TECHNICAL BRANCHES QUARTERLY REPORT FOR PERIOD ENDING SEPTEMBER 31, 1958". United States. doi:10.2172/4277479. https://www.osti.gov/servlets/purl/4277479.
@article{osti_4277479,
title = {MTR-ETR TECHNICAL BRANCHES QUARTERLY REPORT FOR PERIOD ENDING SEPTEMBER 31, 1958},
author = {McCollom, K.A. ed.},
abstractNote = {6 4 6 8 7 8 6 7 9 6 2 6 G 8 1 6 : 9 5 6 8 4 8 5 MTR while fueled with plutonium. Slight modifications to the reactor control system allowed safe operation despite the lower delayed neutron fraction from plutonium. ETR Technical Assistance. Three major loop experiments scheduled for iusertion in the ETR have bcen inserted in the ETRC to study neutron aux and reactivity effects. An experimental comparison has shown the equivalence of the reactivity of boron cortained in plastic tape and boron in boric aeid for use in the determination of boron in fuel elements. Reactor physics measurements have been made with the same fuel elements and rod positions in both the ETR and ETRC showing that the slightly higher reflector efficiency in the ETRC gives a higher weighting function near the edge of the reactor and a flatter neutron flux distribution than in the ETR. A system has been designed to allow a portion of a chosen shim or safety rod in the ETR to be used as the regulating rod in an on-off servo control. Calculations have been made of the maximum permissible step insertion of reactivity in the ETR for a special case. The gamma heat has been measured at the beginning and end of a cycle and the thermal neutron flux has been measured at three times during a cycle to show their variation in the ETR. Reactor Physics and Engineering. Preliminary out-of- pile heat transfer tests have been started in the nucleate boiling region to provide basic heat transfer data in the convective and subcooled boiling regions and in the burnout regions of fuel elements. A program has been developed to study reaction rates between water and metals below and above their melting points to determine potential hazard to water-cooled nuclear reactors. Studies are proceeding to explain the mechanism of radiation damage in construction materials for testing reactors and their experiments. Two plutonium fuel elements have been hydraulically tested satisfactorily prior to the full core loading in the MTR. The gamma decay dose rates from six fuel elements run in the plutonium loading of the MTR have been followed. Irradiations to 60% burnup have been obtained on the samples in the fuel plate irradiation program. The portion of the capsule irradiation program to study the Gas Cooled Power Reactor fuel element that involves long tcrm prototype irradiations has been undertaken. A self-balancing resistivity instrument in thc range of micro-ohms has been developed for detection of resistivity changes in irradiated samples in the MTR hot cell. Experiments performed in the RMF to measure the average poison cross section per fission of fission products have shown that the cross section for Pu- 239 is considerably larger than that for U-235. Reactivity measurements on four Savannah River thorium slugs irradiated in the MTR were studied for the fission product transicnt and the U-233 build-up from Pa-233 dccay. The neutron spectrum of a reactor location has been constructed to fair accuracy from thrce measurements, the thermal flux, the cadmium ratio, and the fast flux. Nuclear Physics. Eta measurements for U-233 from 0.07 to 11 ev are reported. The most probable prompt neutron energies produced by thermal neutron fission of the three isotopes U-233, U-235, and Pu-239 were compared. Simultaneous fission and total cross section measurements are being continued with a view toward further refinements in the multilevel fitting of fission, total and scattering cross sections, and eta measurements of U-233. Total cross seetions of Au, B, Y, Np, and Ir were measured. The half-life of Ta-180 was determined to be greater than 10/sup 11/ years. The crystal spectrometer was},
doi = {10.2172/4277479},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1958},
month = {12}
}