Simulation of the implantation of recoils and displacement production in the 316 stainless steel mercury-container vessel at SNS

In this study, the focus is on the possible effect of mercury and transmuted atom recoils that are implanted into the wall of the stainless steel container vessel at SNS. Two computer codes were used: Los Alamos high energy transport (LAHET) and the stopping and range of ions in matter (SRIM). LAHET provided information of the energy distribution of the recoils upon bombardment. Also, SRIM simulated the transport of recoils through the mercury layer adjacent to the stainless steel wall and into the wall itself, and provided recoil and displacement concentration profiles in the wall. The calculated recoil and displacement concentrations in the near-surface region of the wall appear to be quite significant. The recoil and displacement concentrations per year at the surface are determined to be about 0.0015 recoil atoms/wall atom and about 17 dpa at the center of an incident proton beam. These concentrations fall to about one-half of the surface values at a penetration distance of about 0.1 μm, and the concentrations become negligibly small at 0.5 μm and beyond.