Weapons waste

Neutron activation is an important technique in the study of significant concentrations of actinide and rare earth elements in the nuclear weapon waste. 

There are very many applications of gamma-ray spectrometry. Having already discussed environmental measurements in Chapter 16, in this chapter I discuss a number which, to me, seem to be of particular interest. Each of them deserves a much broader treatment but time and space limit me to a general introduction. Each of them draws upon the principles developed in previous chapters, the idea being to illustrate how academic, and perhaps theoretical, ideas find their expression in practical uses. As it happens, the examples are related in the sense that in these applications gamma spectrometry could be said to help make ordinary life safer measurements in support of the Comprehensive Test Ban Treaty (CTBT) help to prevent the proliferation of nuclear weapons, waste monitoring helps to ensure that radioactive waste is disposed of properly and safeguards measurements make sure that nuclear material is properly accounted for. 

Plutonium (Pu) is an artificial element of atomic number 94 that has its main radioactive isotopes at 2 °Pu and Pu. The major sources of this element arise from the manufacture and detonation of nuclear weapons and from nuclear reactors. The fallout from detonations and discharges of nuclear waste are the major sources of plutonium contamination of the environment, where it is trapped in soils and plant or animal life. Since the contamination levels are generally very low, a sensitive technique is needed to estimate its concentration. However, not only the total amount can be estimated. Measurement of the isotope ratio provides information about its likely... 

Nuclear wastes are classified according to the level of radioactivity. Low level wastes (LLW) from reactors arise primarily from the cooling water, either because of leakage from fuel or activation of impurities by neutron absorption. Most LLW will be disposed of in near-surface faciHties at various locations around the United States. Mixed wastes are those having both a ha2ardous and a radioactive component. Transuranic (TRU) waste containing plutonium comes from chemical processes related to nuclear weapons production. These are to be placed in underground salt deposits in New Mexico (see... 

Chemical processing or reprocessing (39) of the fuel to extract the plutonium and uranium left a residue of radioactive waste, which was stored in underground tanks. By 1945, the reactors had produced enough plutonium for two nuclear weapons. One was tested at Alamogordo, New Mexico, in July 1945 the other was dropped at Nagasaki in August 1945. 

Weapons materials from production reactors were accumulated during the Cold War period as a part of the U.S. defense program. Prominent were tritium, ie, hydrogen-3, having a of 12.3 yr, and plutonium-239, 1/2 = 2.4 X lO" yr. The latter constitutes a waste both as a by-product of weapons fabrication in a waste material called transuranic waste (TRU), and as an excess fissionable material if not used for power production in a reactor. 

Transuranic Waste. Transuranic wastes (TRU) contain significant amounts (>3,700 Bq/g (100 nCi/g)) of plutonium. These wastes have accumulated from nuclear weapons production at sites such as Rocky Flats, Colorado. Experimental test of TRU disposal is planned for the Waste Isolation Pilot Plant (WIPP) site near Carlsbad, New Mexico. The geologic medium is rock salt, which has the abiUty to flow under pressure around waste containers, thus sealing them from water. Studies center on the stabiUty of stmctures and effects of small amounts of water within the repository. 

The Bush Administration (1989-1993) had a similar free marketplace philosophy as Reagan, hut faced the daunting task of having to start directing billions toward cleaning up after forty years of neglect at the contaminated weapons complex, particularly the federal facilities at Savannah River South Carolina, Hanford Washington, and Rocky Flats Colorado. The cleanup plan was fourfold characterize and prioritize all waste cleanups at departmental sites, con-... 

Other options for eliminating weapons-grade plutonium arc to seal it permanently in solid radioactive waste and dispose of it in waste repositories, and to use the plutonium to fuel fast neutron reactors (without reprocessing the plutonium into a MOX fuel). 

In the former U.S.S.R. vast areas of the counti y are contaminated by poor handling of nuclear waste, especially from that associated with the manufacturer of weapons. Some radioactive waste, espe-... 

The political problems with profound economic impact could include, for example, the significance of the continuing worldwide growth of nuclear power, with such issues as the use of Highly Enriched Uranium (HEU) and Plutonium obtained from tire dismantling of U.S. and former USSR nuclear weapons the urgency of nonproliferation the disposal of civilian and military nuclear waste nuclear power alternatives. 

The fact that spent fuel reprocessing and recycle are essential components ofgood nuclear non-proliferation and radioactive waste management practices. These actions are needed so that more efficient use can be made offissionablc materials, and unwanted radioactive fission products can be disposed of without need for permanent safeguards. In addition, potential weapons usable materials are destroyed through beneficial use. 

While public understanding of nuclear issues may lack sophistication and is often based on inadequate or even misleading information, the public s assessments are not irrational. Having been told over many years that spent fuel is nuclear waste, it is only natural that the public should insist on its disposal. If and when effectively informed ofthe fact that spent fuel is not a waste but an energy resource, there is every reason to believe that the public will reject its deliberate burial and favor its storage under secure conditions, just as it now favors consuming, rather than immobilizing, surplus weapons plutonium. 

The 239j240pu can (je accounted for as being from nuclear weapons-produced fallout over the past 30 years, and not from the waste disposal canisters. The mechanism must be by transport and redistribution of the fine floculent sediment at the sediment-water interface. Because of the significant amount of sediment which is being transported down-canyon, any leakage from the canisters would probably be scavenged locally by the environmental sediment material. 

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