Nuclear Propulsion Neg

**HEU Trade-Off D/A HEU – 1NC

Download 0.87 Mb.
Size0.87 Mb.
1   ...   55   56   57   58   59   60   61   62   ...   78

**HEU Trade-Off D/A


There’s just enough highly enriched uranium for medical isotope protection – increased demand forces shortages

Johnston 10 (Hamish, editor @, 12/3/10, JPG

Currently, all of the world's nine major isotope-producing reactors are running – one each in Canada, South Africa, Australia and Argentina and five in Europe. However, the HLG-MR report cautions that shortages could be expected as demand continues to grow, some reactors are shut down and constraints remain on regional processing capacity. Molybdenum-99 has a half-life of 66 h, which is not long enough for the isotope to be stockpiled. It is produced by irradiating a target containing uranium-235 inside a nuclear reactor. The molybdenum-99 is then extracted from the target in a processing facility. The uranium targets cannot be transported by air, which means that processing should be located less than 1000 km from the reactor. There are currently six major processing centres worldwide – all near major reactors. The report points out that the processing capacity in some regions is not enough to support increased target irradiation in those locales. Indeed, during a recent global isotope shortage, reactors in Europe could not crank out targets at full capacity due to a lack of processing facilities. As a result, the HLG-MR recommends that production and processing capacities should be coordinated on a regional level.

No Space nuclear reactors are set to launch now – plan shifts HEUs from other priorities

Kuperman 11 (Alan, Assoc. Prof of Global Policy Studies @ U Texas, 4/22/11, JPG

No SNR projects have been launched since 1988, nor are any being seriously considered for the near future in the U.S. or elsewhere. Right now policymakers have a unique opportunity to set SNR policy to align with the international norm of HEU phase-out both in the U.S. and internationally. Policy changes will become much more politically and financially costly once governments start seriously considering SNR projects again. SNRs are not yet the highest priority for the HEU phase-out mission, but the use of HEU in SNRs is still a real proliferation concern. Even if SNRs can be relied on to safely launch, operate, and retire in outer space, the substantive policy issue is that HEU phase-out must be nondiscriminatory to be successful. Non-weapon states will have stronger diplomatic grounds to resist global nonproliferation norms if the weapon states fail to reinforce them concretely and by example. Seemingly benign exceptions could compromise the global phase-out of HEU. In short, security policies that are not adopted domestically will be difficult to push internationally. There are also domestic political barriers to eliminating HEU from use in SNRs. SNRs present the most sophisticated technical challenge to the global HEU phase-out mission because HEU’s high energy density and low radioactivity make it a uniquely attractive fuel for space power and propulsion. Further, the tenuous nature of Congressional commitments to space exploration and research makes government scientists resistant to policy mandates that increase the funding or time required to bring projects to completion. Both factors can make a project vulnerable to discretionary spending cuts in the Congressional budget process. HEU also has tradition on its side, because all SNRs ever launched (35 by the Soviet Union and one by the United States) have used weapons-grade HEU (90% enriched or higher) as reactor fuel.1 Policy solutions that phase out HEU from use in SNRs could be expensive and therefore provoke resistance from government researchers and scientists, especially mandates that would require the use of LEU. The higher mass of uranium associated with any conversion from HEU to LEU would increase the cost of space reactors more than any other application due to the premium on minimizing weight for space research projects.


Stable supply of medical isotopes prevents mass heart disease and cancer deaths – diagnoses 200,000 deadly illnesses each day

Ruth et. al. No Date (Thomas – Senior Research Scientist, TRIUMF and BC Cancer Agency, JPG

Around the world each day, doctors use radiochemistry and medical isotopes for several hundred thousand patients to diagnose illness and study disease. Heart disease and cancer are the leading causes of death for North Americans, so early and accurate diagnoses can help tremendously in mitigating the impact of these common killers both on the individual and on the costs to society. So how does radiochemistry fit into the healthcare system? In a sense, the field of "medicine using radiation for imaging and/or treatment" (now called nuclear medicine) had its start with the discovery of radioactivity by Henri Becquerel in Paris in 1896. Becquerel had accidentally left photographic plates used for X-rays in a drawer next to some natural Uranium salts and discovered they were highly exposed a week later . It was later realized that this exposure was due to "alpha particles" (α) emitted in the radioactive decay of the Uranium and detected by the photographic plates. Of the common forms of radioactivity, α-decay (the nuclei of He atoms), β-decay (e+ or e-) and γ-decay (from nuclear excited states), it is only the β/γ- decay sequence that is presently important in nuclear imaging techniques, since it is only γ-rays that are penetrating enough to be detected outside the body. In the future, the use of alpha emitters internally for therapeutic applications could also be important. Every organ in our body acts differently from a chemical point of view. Each organ also has its own biochemical specificity which provides the basis for various radioisotopes to be incorporated into biologically active molecules to create '"radio-pharmaceuticals" --- targeted drugs which will preferentially be used by certain organs in the body or certain chemical pathways in the body. To be of use for imaging, the radioisotope that is attached to the pharmaceutical (thereby "labeling it") must satisfy two important criteria: (1) Its half-life must be long enough for easy handling but not too long to leave residual activity in the patient; and, (2) Its emitted γ-decay energy must be high enough to be easily detected outside the body, but not too high as to overpower the imaging camera. The main radioisotope that matches these requirements almost perfectly is Technetium-99m (Tc-99m, where "m" means "metastable"), with a half-life of 6 hrs and a γ energy of 140 keV (kilo-electron volts). It is for these reasons that something like 80% of all nuclear medicine procedures utilize Tc-99m world wide, which translates into something like 200,000 procedures every day. Tc-99m has traditionally been made available from the β-decay of Molybdenum-99 (Mo-99), half-life of 66 hours, from a "generator" or "cow," a concept that was developed in the late 1950s by scientists at Brookhaven National Laboratory in New York. The Mo-99 parent is usually produced from a nuclear reactor in one of two ways: either from thermal neutron capture on stable Mo-98 in an (n, γ) reaction, or from neutron-induced fission of Uranium-235, the latter being the basis of most commercially produced Tc-99m. The fission yield of Mo-99 is much higher and can give specific activities of >5000 Ci/g (Curies/g where 1 Ci= 3.7 x 10^10 disintegrations per second). Another key aspect of this generator concept is in the loading of an ion-exchange column with Mo-99 as a molybdate ion (Na2MoO4) in solution, where it is held securely. Following a decay period to allow growth of the Tc-99m daughter, a saline solution is used to rinse the column, specifically releasing the Tc-99m where it is available for preparing the requisite radiopharmaceutical. This process can be repeated many times as the Tc-99m is again built up from Mo-99 decay after milking." Typically a Mo-99/Tc-99m generator is used for about a week with daily elutions before it is necessary to reload the column. For decades radio-chemists have worked to develop better approaches for attaching the Tc-99m to organ-specific radiopharmacueticals in order to facilitate the utility of nuclear imaging in diagnosing disease. This important contribution to the field of medicine, resulting from the synergistic overlap of the disciplines of biology, radiochemistry, nuclear physics and engineering, has functioned smoothly for half a century now, relying on the relatively inexpensive and reliable supply of Mo-99.

Share with your friends:
1   ...   55   56   57   58   59   60   61   62   ...   78

The database is protected by copyright © 2019
send message

    Main page