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Rochman, D.*; 湊 太志; 渡邉 友章; 他52名*
EPJ Nuclear Sciences & Technologies (Internet), 10, p.9_1 - 9_83, 2024/10
This paper summarized the efforts performed to understand decay heat estimation from existing spent nuclear fuel (SNF), under the auspices of the Working Party on Nuclear Criticality Safety (WPNCS) of the OECD Nuclear Energy Agency. Needs for precise estimations are related to safety, cost, and optimization of SNF handling, storage, and repository. The physical origins of decay heat (a more correct denomination would be decay power) are then introduced, to identify its main contributors (fission products and actinides) and time-dependent evolution. Due to limited absolute prediction capabilities, experimental information is crucial; measurement facilities and methods are then presented, highlighting both their relevance and our need for maintaining the unique current full-scale facility and developing new ones. The third part of this report is dedicated to the computational aspect of the decay heat estimation: calculation methods, codes, and validation. Different approaches and implementations currently exist for these three aspects, directly impacting our capabilities to predict decay heat and to inform decision-makers. Finally, recommendations from the expert community are proposed, potentially guiding future experimental and computational developments.
Andel, B.*; Van Duppen, P.*; Andreyev, A. N.; Blazhev, A.*; Grawe, H.*; Lica, R.*; Nadja, H.*; Stryjczyk, M.*; 他52名*
Physical Review C, 104(5), p.054301_1 - 054301_13, 2021/11
被引用回数:6 パーセンタイル:58.46(Physics, Nuclear)A new -decaying state in
Bi has been identified at the ISOLDE Decay Station at the CERN-ISOLDE facility. A preferred
assignment was suggested for this state based on the
-decay feeding pattern to levels in
Po and shell-model calculations. The half-life of the
state was deduced to be
min. The deexcitation of the levels populated in
Po by the
decay of this state was investigated via
coincidences and a number of new levels and transitions were identified. Shell-model calculations for excited states in
Bi and
Po were performed using two different effective interactions: the H208 and the modified Kuo-Herling particle interaction. Both calculations agree on the interpretation of the new
-decaying state as an
isomer and allow for the tentative assignment of shell-model states to several high-spin states in
Po.
Carroll, R. J.*; Podolyk, Zs.*; Berry, T.*; Grawe, H.*; Alexander, T.*; Andreyev, A. N.; Ansari, S.*; Borge, M. J. G.*; Brunet, M.*; Creswell, J. R.*; et al.
Physical Review Letters, 125(19), p.192501_1 - 192501_6, 2020/11
被引用回数:12 パーセンタイル:62.65(Physics, Multidisciplinary)The decay of
Hg into the one-proton hole, one neutron-particle
Tl
nucleus was investigated at CERN-ISOLDE. Shell-model calculations describe well the level scheme deduced, validating the proton-neutron interactions used, with implications for the whole of the
,
quadrant of neutron-rich nuclei. While both negative and positive parity states with spin 0 and 1 are expected within the
window, only three negative parity states are populated directly in the
decay. The data provide a unique test of the competition between allowed Gamow-Teller and Fermi, and first-forbidden
decays, essential for the understanding of the nucleosynthesis of heavy nuclei in the rapid neutron capture process. Furthermore, the observation of the parity changing
decay where the daughter state is core excited is unique, and can provide information on mesonic corrections of effective operators.
Gottardo, A.*; De Angelis, G.*; Doornenbal, P.*; Coraggio, L.*; Gargano, A.*; Itaco, N.*; Orlandi, R.; 他52名*
Physical Review C, 102(1), p.014323_1 - 014323_8, 2020/07
被引用回数:8 パーセンタイル:60.84(Physics, Nuclear)Reduced transition probabilities have been measured for the neutron-rich Ni nuclei with relativistic Coulomb excitation performed at the RIKEN Nishina Center. Excitation energies compare well with the result of large-scale shell-model calculations, while
values are larger than predicted. This could indicate an increasing contribution of proton excitations across the
shell closure when approaching
Ni.
Damone, L.*; Barbagallo, M.*; Mastromarco, M.*; Cosentino, L.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他152名*
Physical Review Letters, 121(4), p.042701_1 - 042701_7, 2018/07
被引用回数:61 パーセンタイル:92.06(Physics, Multidisciplinary)We report on the measurement of the Be(n,p)
Li cross section from thermal to approximately 325 keV neutron energy, performed in the high-flux experimental area (EAR2) of the n_TOF facility at CERN. This reaction plays a key role in the lithium yield of the big bang nucleosynthesis (BBN) for standard cosmology. The only two previous time-of-flight measurements performed on this reaction did not cover the energy window of interest for BBN, and they showed a large discrepancy between each other. The measurement was performed with a Si telescope and a high-purity sample produced by implantation of a
Be ion beam at the ISOLDE facility at CERN. While a significantly higher cross section is found at low energy, relative to current evaluations, in the region of BBN interest, the present results are consistent with the values inferred from the time-reversal
Li(p,n)
Be reaction, thus yielding only a relatively minor improvement on the so-called cosmological lithium problem. The relevance of these results on the near threshold neutron production in the p+
Li reaction is also discussed.