Effects of Electron Irradiation on Candidate Materials for Target Window in Accelerator-Driven Molybdenum-99 Production
- Argonne National Lab. (ANL), Argonne, IL (United States)
NorthStar Medical technologies is planning to produce Mo-99 through the photo-nuclear reaction Mo-100 (γ,n) Mo-99 utilizing multiple high-power electron accelerators. In this approach, the production target consists of multiple thin disks of metal Mo-100 cooled by helium gas at high (300–400 psi) pressure [4]. The cost of enriched Mo-100 is on the order of $500 - 1,000 per gram, which makes a smaller target desirable and requires achieving the highest possible electron flux on the target. The heat deposition in the entrance window limits the maximum flux because the window separates the vacuum in the accelerator beam line from the high-pressure helium in the target and is only cooled on one side by the helium flow. Because the window is continuously under stress from the helium pressure and the heat from the electron beam, it is desirable to estimate a lifetime for the window and develop a replacement schedule for the target holder. Such an estimate requires the ability to predict changes in the window material properties under electron irradiation. Candidate materials for the Mo-99 production target window are Inconel 718, 250 maraging steel, and beryllium. These materials encompass a wide range of thermal conductivity, thermal expansion coefficients, Young’s modulus, tensile strength and tensile ductility. The Mo-99 target window is subjected to internal pressure from the helium coolant and thermal stresses. The operating conditions and relative advantages of each material have been described previously [1]. The current work investigates the effects of electron irradiation on the tensile properties of these materials. Axial tensile tests were conducted with electron-irradiated samples and results were compared to baseline results generated for as-fabricated materials.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1493064
- Report Number(s):
- ANL-19/05; 150270
- Country of Publication:
- United States
- Language:
- English
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