Waste permanent isolation

The work presented here enables us to get a clearer picture of the problems involved in permanent isolation of radioactive wastes from the environment. 

Over the last year or so, several papers have been published which have been concerned with the adequacy of the technology for providing for permanent isolation of radioactive wastes. In all cases the concerns that have been raised have focused on the second set of issues, rather than the first, so that the apparent dispute between those who say that there are no technical problems and those who say that there are still some to be solved is perhaps more a dispute as to what particular set of problems are being described. 

In the context of NWPA, requires permanent isolation means disposal in a geologic repository, or in an alternative system that would provide equivalent capabilities for isolation of the waste from the biosphere, with no intention of retrieving the waste after facility closure. 

The definition of high-level waste in Clause (B) of NWPA given above represents a potentially significant departure from previous definitions in that it allows the development of a generally applicable definition of high-level waste that is not based on the source of the waste. However, as in Clause (A), highly radioactive and requires permanent isolation in Clause (B) are not quantified. 

High-level waste is any waste that is highly radioactive and requires permanent isolation. 

Transuranic waste and equivalent is any waste that requires permanent isolation but is not highly radioactive. 

In these definitions, highly radioactive refers to high levels of decay heat and external radiation, due primarily to shorter-lived radionuclides, and requires permanent isolation refers to high concentrations of long-lived radionuclides i.e., these terms have the same interpretations as in the definitions of high-level waste in NWPA. 

An alternative to permanent isolation of the spent nuclear fuel is monitored, retrievable storage. This method has an advantage since, if reprocessing to remove potentially useful materials such as plutonium becomes feasible, the wastes are still accessible. The argument for this plan is that the technologies and alternatives available to society a few hundred years... 

HLW generally refers to materials requiring permanent isolation from the environment. It frequently arises as a by-product of nuclear power generation (reprocessing streams or spent fuel) or from the isolation of fissile radionuclides from irradiated materials to be used in nuclear weapons production. When nuclear fuel from reactor operations (civilian or defense) is chemically processed, the radioactive wastes include highly concentrated liquid solutions of nuclear fission products. Typically, these waste streams are solidified either in a glass (vitrification) or in another matrix. Both the liquid solutions and the vitrified solids are considered HLW. If the nuclear fuel is not processed, it too, is considered as HLW and must be dispositioned. The path most often proposed is direct, deep geologic isolation. 

Each of these options has serious poKtical, environmental, and/or technical issues that must be addressed. Among the options discussed for disposing of these materials, an international consensus has emerged that deep geologic disposal is the most appropriate means for isolating such wastes permanently from man s environment (NAS 1957). 

Without going into great detail about the issues described in these papers, I would like to make the point that the response of the waste isolation program to these papers will be to use them to help us to design a technical program plan to ensure that these issues are adequately addressed, as indeed they must be, before we can commit radioactive waste to irretrievable permanent disposal. 

This experiment provides considerable confidence in the concept of waste immobilization in glass as one step toward isolating the long-lived radioactive by-products of nuclear power from man s environment. Of course, the immobilized material would not be placed deliberately in shallow ground water for permanent disposal. The consensus today is for deep underground disposal in a stable geological formation (21). 

Employers should take appropriate preventative measures against occupational exposure. These include engineering controls and work practice controls. Examples of engineering controls include biohazard hoods, puncture-resistant sharps containers, mechanical pipette devices, and other devices that permanently remove the hazard or isolate individuals from exposure. Organizations must evaluate and incorporate new safer devices including needleless devices, needles with sheaths, and blunt suture needles. Work practice controls must include hand washing policies, sharps handling procedures, proper waste disposal techniques, and other actions that would reduce the likelihood of exposure. 

In 1982, lawmakers passed the Nuclear Waste Policy Act, which established a program to build this countiy s first underground nuclear waste repositoiy, a permanent disposal site for nuclear waste. In 1987, Yucca Mountain, Nevada, was chosen for study as a potential site. The stable rock formations deep underground combined with sparse population and little rainfall make it an ideal location for the site. Nuclear waste will be encased in several layers of containment material and placed in tunnels drilled out of the rock formations 1000 ft beneath the ground. The storage facility should keep these materials isolated from us and from the environment for the foreseeable future. However, as might be expected, the construction of the facility is controversial, with many opposing even the idea. The facility had been scheduled to be operational in 2010, but delays have pushed back that date to 2017 at the earliest. 

Yucca Mountain in Nevada has been chosen as a potential site for a permanent nuclear waste facility. The stable rock formations 1000 ft beneath the surface should keep nuclear waste isolated from the environment for thousands of years. 

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