How It Works
SHINE’s demonstrated technology brings two major technical innovations to modernize traditional medical isotope production, allowing for a safer, greener, more efficient and less expensive method of moly-99 production:
No nuclear reactor.
The first major improvement over existing production methods is the replacement of a highly-specialized nuclear reactor with a low-energy, accelerator-based neutron source. This source functions by colliding deuterium ions with tritium gas to cause fusion. The fusion reaction results in high energy neutrons and helium-4. In other words, the accelerator takes a radioactive by-product created by nuclear power plants (tritium) and turns it into the same clean, harmless gas used to make balloons float.
The neutrons produced by this reaction then strike the uranium target to produce moly-99.
Removing the nuclear reactor as the neutron source eliminates almost all of the nuclear waste associated with production today, resulting in a safer, greener process and giving SHINE a significant cost-advantage.
Reusable liquid target.
The second technological leap forward is the target material itself. Instead of employing solid highly-enriched uranium plates that are used once and then disposed of, the uranium in SHINE’s target is low-enriched uranium (LEU) that is dissolved in a water-based solution. Neutrons from the accelerator enter the water and strike the uranium, causing fission. Moly-99 is created just as in the solid target case but is already dissolved in solution. After several days, the solution is drained and passed through a filter which retains molybdenum, but allows the uranium to pass through. The solution is then pumped back into the production system and reused. This recyclable target further reduces waste production, increases the ease of separation, and decreases the amount of uranium required to make a given quantity of technetium-99m by many times. And the LEU target eliminates any chance of highly-enriched uranium (HEU) diversion for nuclear weapons production. For more information on the importance of LEU, see below.
1. Target Solution: Low-enriched uranium (LEU) is created by diluting former nuclear weapons to the point of no longer being a threat. Once intended to cause harm to billions, the LEU will be transformed by the SHINE process to help provide healthcare for a billion patients. SHINE receives LEU from the US Government, and dissolves it, creating a uranyl sulfate mixture. This mixture is then pumped into a target solution tank.
2. Accelerator: Electrons are stripped from deuterium using microwave energy. The resulting positively-charged deuterium ions are shaped into a beam and accelerated to about 10 million mph.
3. Fusion Chamber: The deuterium ions are accelerated into a gas target made of another isotope of hydrogen (tritium) resulting in clean fusion reactions that generate neutrons. These neutrons then pass into the target solution tank.
4. Fission Target: The neutrons cause the uranium nuclei in the target solution tank to split in a process known as fission. This process creates multiple elements, including moly-99 and other useful isotopes.
5. Moly Extraction: The target solution is irradiated for approximately 1 week, then pumped through an extraction column. Moly sticks to the column and the rest of the target solution is returned for re-use. A separate solution is then pumped through the extraction column to take the moly to purification.
6. Purification: A proven chemical process purifies the moly-99 to meet pharmaceutical standards and customer specifications.
7. Distribution: Moly-99 decays at a rate of about 1% per hour, so it must be quickly transported for use by doctors. Moly-99 is flown from the SHINE facility to our customers, where it will be packaged and sent to hospitals for use in procedures such as stress tests and bone scans. Moly-99 is used in over 50,000 procedures every day in the U.S. alone.
At the heart of the SHINE system is the world’s strongest commercial neutron generator. This low-energy, accelerator-based demonstrated technology is what eliminates the need for a nuclear reactor and allows the SHINE system to operate sub-critically, giving SHINE a significant cost advantage.
SHINE’s full-size accelerator has completed a number of important demonstrations including 132 consecutive hours of operation with 97% up-time. This accomplishment represented an industry first for extended-operation reliability of a gas target neutron generator and is an important demonstration of the robustness of the neutron generator.
Tests performed by Los Alamos National Laboratory (funded by the U.S. DOE Department of Science) have found highly efficient recovery of Mo-99 from SHINE’s liquid target, and that this yield did not change when the target solution was recycled.
Argonne National Laboratory (funded by the U.S. DOE Department of Science) has demonstrated the production, separation, and purification of molybdenum-99 from SHINE’s innovative liquid target. The resulting Mo-99 product purity was equivalent to the Mo-99 used in the supply chain today. Known as Mini-SHINE, the demonstration uses the same process flows that will be used in the SHINE manufacturing facility and validates every step of the production chemistry: from plant-relevant irradiation conditions through purification of the Mo-99 to current industry standards. The work was supported by the Department of Energy’s National Nuclear Security Administration’s Mo-99 Program.
Mo-99 from this demonstration was then shipped to GE Healthcare and packaged in GE’s DRYTEC™ Generator.
After successfully producing technetium-99m in the DRYTEC™ Generator using SHINE Mo-99, GE tested it in the preparation of finished radiopharmaceuticals using kits of GE Healthcare Tc-99m-based products: Myoview™ and Ceretec™. Successful quality control testing was performed on the reconstituted kits, indicating feasibility for Tc-99m radiopharmaceuticals prepared using this material.
The positive results of this test confirmed that Mo-99 produced by SHINE’s demonstrated technology can be incorporated into the existing Mo-99 supply chain. Use of SHINE-produced Mo-99 in generators will not require changes to radiopharmacy practices or how the resulting Tc-99m is used in scanning procedures. This is the first time that a non-reactor technology has ever produced moly-99 of the same quality as nuclear reactors.
HEU vs. LEU
Until very recently, all major moly-99 producers used targets made from highly-enriched uranium or HEU—uranium with a composition of 20% uranium-235 or more. Although moly-99 can be produced very efficiently from this material, HEU can also be made into nuclear weapons and is, therefore, a risk to global security. In the traditional production process, after the moly is separated from the target, almost all of the HEU remains and is not reused. Instead, it is stored indefinitely at a relatively low-security site. Historically, the U.S. has exported enough HEU to make a few nuclear bombs each year for the purpose of molybdenum-99 production. This situation has created a direct conflict between the health and the security of U.S. citizens, such that a reliable supply of medical isotopes comes at the expense of the increased threat posed by the potential diversion of HEU for use in nuclear weapons.
The alternative to HEU is low-enriched uranium or LEU—uranium with a composition of less than 20% uranium-235. Because the uranium-235 in LEU is diluted with a large amount of uranium-238, it cannot be made into a nuclear weapon without very sophisticated modifications and is therefore much less of a proliferation risk. A number of scientific investigations have shown that there is no technological barrier preventing the use of LEU in the traditional production process, with some modification. However, many producers have proved reluctant to change. SHINE’s demonstrated technology is 100% LEU-based from start to finish.