11. |
Thermal Neutron Spectrum in a Moderator with a Temperature Discontinuity |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 102-107
PearceR. M.,
KennedyJ. M.,
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摘要:
AbstractThe variation in space of the thermal-neutron spectrum close to a temperature discontinuity in a non-absorbing free gas has been calculated in the diffusion approximation on a G-20 computer. This spectrum forms a basis for testing two simple rethermalization models. The two-overlapping-group model due to Selengut gives very good agreement with the computer calculations when used with an improved transfer cross section. The single-Maxwellian model in which the neutron temperature varies exponentially with distance from the discontinuity does not give as good agreement.
ISSN:0029-5639
DOI:10.13182/NSE64-A19794
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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12. |
Neutron Thermalization in Graphite |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 108-129
WiknerN. F.,
JoanouG. D.,
ParksD. E.,
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摘要:
AbstractIn this work our ability to understand thermal-neutron spectra in graphite-moderated reactor systems is examined on the basis of a theoretical description of neutron scattering that begins at the microscopic level.The first step in this examination consists in determining the extent to which current ideas of lattice vibrations in graphite are consistent with measurements of the scattering law and of specific heats. Theoretical scattering laws and specific heats based on a few different models for lattice vibrations are compared with experimental results. The theoretical scattering law is calculated within the framework of the incoherent and Gaussian approximations. The question of the accuracy of the latter approximation is discussed in detail. No estimates have been made of the magnitude of the uncertainty introduced by the use of the incoherent approximation.Following the discussion of neutron scattering at the microscopic level, we show (1) the sensitivity of various integral properties of the scattering kernel and of thermal-neutron spectra in a homogeneous medium to the frequency distribution of lattice vibrations, and (2) the accuracy of the Gaussian approximation for use in computing thermal-neutron spectra in graphite. Finally, a detailed theoretical model for the scattering of neutrons by graphite is applied to the problem of comparing calculated neutron spectra with the measured spectra in two strongly heterogeneous, graphite-moderated assemblies.These considerations show that current theoretical ideas concerning the frequency distribution of lattice vibrations in graphite are consistent with the results of the measurement of the scattering law, with the specific heat, and with most of the available results of the measurements of thermal-neutron spectra in reactor-like configurations.
ISSN:0029-5639
DOI:10.13182/NSE64-A19795
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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13. |
Notes |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 130-130
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ISSN:0029-5639
DOI:10.13182/NSE64-A19796
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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14. |
Two-Group Material Bucklings in a Two-Region System |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 131-131
LewisW. B.,
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ISSN:0029-5639
DOI:10.13182/NSE64-A19797
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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15. |
The Effect of Chemical Binding on the Milne - Problem Extrapolation Distance |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 132-133
WilliamsM. M. R.,
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ISSN:0029-5639
DOI:10.13182/NSE64-A19799
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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16. |
Chemistry of Nuclear Power |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 134-135
YostDon M.,
GomezPancho P.,
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ISSN:0029-5639
DOI:10.13182/NSE64-A19800
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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17. |
The Atomic Energy Deskbook |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 135-135
DoanRichard L.,
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ISSN:0029-5639
DOI:10.13182/NSE64-A19801
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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18. |
Nuclear Reactor Control Engineering |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 136-136
SchultzM.A.,
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ISSN:0029-5639
DOI:10.13182/NSE64-A19802
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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19. |
Perturbation Theory and the Nuclear Many Body Problem |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 137-138
BeckerRichard L.,
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ISSN:0029-5639
DOI:10.13182/NSE64-A19804
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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20. |
Methods in Computational Physics, Vol. I |
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Nuclear Science and Engineering,
Volume 19,
Issue 1,
1964,
Page 138-139
GelbardEly M.,
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ISSN:0029-5639
DOI:10.13182/NSE64-A19805
出版商:Taylor&Francis
年代:1964
数据来源: Taylor
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