Calculation and verification of neutron irradiation damage with differential cross sections

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:456

Article

Chen, Shengli^1,3  Bernard, David¹  Tamagno, Pierre¹  Tommasi, Jean¹  Bourganel, Stephane²  Noguere, Gilles¹  Jean, Cyrille De Saint¹ 

[1] CEA, DEN DER SPRC LEPh, F-13108 St Paul Les Durance, France

[2] CEA Saclay, DEN DM2S SERMA LPEC, F-91191 Gif Sur Yvette, France

[3] Univ Grenoble Alpes, I MEP2, F-38402 St Martin Dheres, France

关键词: Displacement per Atom;    Differential cross section;    Gauss-Legendre Quadrature;    Legendre polynomial;    Fe-56;   

DOI  :  10.1016/j.nimb.2019.07.011

来源: Elsevier

【 摘 要 】

The Displacement per Atom (DPA) rate is conventionally computed with DPA cross sections in reactor applications. The method of direct calculation with energy-angular distributions given in the Center of Mass (CM) frame is proposed and recommended in the present work. The methods for refining and verifying the calculations of DPA cross sections are proposed: (i) Gauss-Legendre-Quadrature-based Piecewise Integration (GLQPI) for ensuring the numeric convergence of integral over emission angle due to the discontinuity of integrand; (ii) verification of the convergence for trapezoidal integration over the secondary energy; (iii) interpolation of double-differential cross sections. For Fe-56 of JEFF-3.1.1, the current numeric integration over emission angle is shown not convergent, whereas the direct trapezoidal over the secondary energy and the direct interpolation of energy-angle-integrated damage are shown accurate. On the other hand, it is shown that the DPA cross sections are overestimated if isotropic angular distributions are assumed. However, the DPA cross section is not sensitive to the high-order Legendre polynomials because the former is an angle-integrated quantity. Numerical results of neutron elastic scattering show that 2 orders of Legendre polynomials can give the DPA rates of Fe-56 within 0.5% overestimation for fission reactors, while 4 orders are required for fusion reactors. For neutron inelastic scatterings-induced DPA, the first order Legendre polynomial is sufficient for both fission and fusion reactors.

【 授权许可】

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