FAST ROSSI-ALPHA MEASUREMENTS OF PLUTONIUM USING ORGANIC SCINTILLATORS

EPJ Web of Conferences

Pozzi S.A.¹  MacDonald A.T.¹  Bravo C.A.¹  Clarke S.D.¹  Hutchinson J.D.²  McSpaden A.T.²  Grove T.J.²  Goda J.M.²  McKenzie G.E.² 

[1] Department of Nuclear Engineering and Radiological Sciences, University of Michigan;NEN-2: Advanced Nuclear Technology Group, Los Alamos National Laboratory;

关键词: neutron noise;    rossi-alpha;    3he;    organic scintillator;   

DOI  :  10.1051/epjconf/202124709025

来源: DOAJ

【 摘 要 】

In this work, Rossi-alpha measurements were simultaneously performed with a 3He-based detection system and an organic scintillator-based detection system. The assembly is 15 kg of plutonium (93 wt% 239Pu) reflected by copper and moderated by lead. The goal of Rossi-alpha measurements is to estimate the prompt neutron decay constant, alpha. Simulations estimate keff = 0:624 and α = 52:3 ± 2:5 ns for the measured assembly. The organic scintillator system estimated α = 47:4 ± 2:0 ns, having a 9.37% error (though the 1.09 standard deviation confidence intervals overlapped). The 3He system estimated α = 37 μs. The known slowing down time of the 3He system is 35-40 μs, which means the slowing down time dominates and obscures the prompt neutron decay constant. Subsequently, the organic scintillator system should be used for assemblies with alpha much less than 35 μs.

【 授权许可】

Unknown