Impact of reactor neutron spectrum on measured spectrum averaged cross sections

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F26722445%3A_____%2F22%3AN0000040" target="_blank" >RIV/26722445:_____/22:N0000040 - isvavai.cz</a>

Alternative codes found

RIV/68407700:21340/22:00365041

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S0306454922004509" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0306454922004509</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.anucene.2022.109418" target="_blank" >10.1016/j.anucene.2022.109418</a>

Result language

angličtina

Original language name

Impact of reactor neutron spectrum on measured spectrum averaged cross sections

Original language description

The cross section averaged over 235U thermal-neutron induced fission spectrum is a fundamental quantity that can be used in evaluation and validation of nuclear data. Many experiments focused on the determination of Spectrum Averaged Cross Sections (SACS) in 235U(nth,f) Prompt Fission Neutron Spectrum (PFNS) in light water reactors using enriched uranium fuel. In these reactors, there is already some amount of water moderator be-tween the uranium fuel and the irradiated sample. Due to the decrease of hydrogen cross-section with neutron energy, the high energy tail of the reactor spectrum in cores with water moderator may be harder than the pure PFNS. This paper aims to compare the shape of the actual reactor spectrum in various core positions of a research light-water reactor differing each from other by the effective water thickness. The spectrum shape is determined both by calculations and experimentally using various high energy threshold reactions. The impact of the photo-nuclear reactions (gamma,n) competing with (n,2n) in production of the same residual nucleus was shown to be less than a percent for most of studied dosimeters. An important exception was found for 197Au(n,2n)196Au dosimeter irradiated in the outcore channel where a notable photo-neutron contribution to the production of 196Au is caused by the neutron production from the high energy gamma-rays from thermal-neutron capture in 54Fe. The corresponding ENDF/B-VIII.0 data turned out to underestimate such gamma-yield by 40 % in comparison with ENDF/B-VI.8. This has improved but however not resolved the disagreement between our measurement and calculations. The remaining deficiency was attributed to the underestimation of the evaluated cross section IAEA/PD-2019 for the 197Au(gamma,n) cross section near the reaction threshold. The later was confirmed by comparison with existing measured data.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

20305 - Nuclear related engineering; (nuclear physics to be 1.3);

Project

<a href="/en/project/EF16_013%2F0001790" target="_blank" >EF16_013/0001790: Strengthening and development of research at Czech Technical University in Prague with the use of research infrastructure VR?1 Training Reactor for research activities</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Annals of Nuclear Energy

ISSN

0306-4549

e-ISSN

1873-2100

Volume of the periodical

179

Issue of the periodical within the volume

109418

Country of publishing house

GB - UNITED KINGDOM

Number of pages

13

Pages from-to

1-13

UT code for WoS article

000860754300004

EID of the result in the Scopus database

2-s2.0-85137155961