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QSA Global, Niowave to collaborate on Ac-225 production using Ra-226
QSA Global, a provider of radioisotope products, and Niowave, a Michigan-based producer of medical radioisotopes, announced that the companies will codevelop a scalable radium purification process using Niowave’s radium-226 processing technology to meet the demand for actinium-225, an alpha-emitter used in the treatment of cancer. According to the companies, the strategic partnership marks a significant advancement in the field of radiopharmaceutical technology, enhancing the supply chain for critical radioisotopes, including Ac-225.
Niowave uses a closed-loop cycle to produce high-purity Ac-225 and other alpha emitters from Ra-226 using a superconducting electron linear accelerator. According to the company’s website, the electron beam impinges on a photon converter to irradiate the Ra-226, inducing a photon-neutron reaction to Ra-225, which decays to Ac-225.
Yongsoo Hwang, P. L. Chambré, T. H. Pigford, W. W.-L. Lee
Nuclear Technology | Volume 90 | Number 2 | May 1990 | Pages 205-214
Technical Paper | Radioacitive Waste Management | doi.org/10.13182/NT90-A34415
Articles are hosted by Taylor and Francis Online.
Salt is a candidate rock to host nuclear waste repositories in many countries. Brine exists in natural salt as inclusions in salt crystals and in grain boundaries. Brine inclusions in crystals move to nearby grain boundaries when subjected to a temperature gradient, because of the temperature-dependent solubility of salt. Brine in grain boundaries moves under the influence of a pressure gradient. Brine consolidates around high-level waste packages a few years after emplacement. Heated salt near the waste package expands against the waste package and surrounding salt, creating high compressive stresses near the waste package and resulting in pressure above the lithostatic pressure. Brine pressure increases because grain-boundary brine expands more than does the salt. This increased pressure gradient causes brine to flow outward into the cooler salt. Outward flow of brine relieves the pressure gradient on the fluid, which finally relaxes to near-lithostatic pressure. Outward brine movement can become a mechanism for radionuclide transport. To determine the extent to which advection by brine in grain boundaries is an important transport mechanism for released radionuclides, it is necessary to estimate the time-dependent migration of brine. The possible role of brine migration in radionuclide transport in a nuclear waste repository is studied. Mathematical derivation of the analysis is given, along with numerical illustrations using parameter values typical of a nuclear waste repository. For heat-emitting wastes and the parameters studied here, brine migration in salt is minuscule, of the order of micrometres per year, localized within a few metres from the waste package, and highly transient, fading away within a few years of waste emplacement.