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CHAPTER 1 - INTRODUCTION
Pages 15-32

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From page 15... ... Together defense nuclear wastes and spent nuclear fuel have been generated at almost 100 sites located throughout the country. At present, high-level defense wastes are in various physical and chemical forms and are stored much of it in underground steel tanks- in several types of facilities, primarily at three U.S. Read the entire page →
From page 16... ... DOE is currently Outlying the Yucca Mountain site by a process caller} "site characterization" to accumulate the information necessary to judge whether it will meet the standard to be set by EPA. If the site is deemed appropriate to be considered in the licensing process and a license application to USNRC is approved, DOE estimates that the earliest date for possible emplacement of high-level radioactive waste at Yucca Mountain would be the year 2010 (C. Read the entire page →
From page 17... ... provides that the stanciard prescribe the maximum annual effective dose equivalent to individual members of the public from releases to the accessible environment. These standards will be the only ones for high-level radioactive waste disposal applicable to the Yucca Mountain site, and are to be promulgated within one year after the Academy submits its study. Read the entire page →
From page 18... ... SCOPE OF THE STUDY The disposal of high-level radioactive waste in a geologic repository initially requires placing radionuclicles in the repository at concentrations far in excess of natural levels. Some radionuclides decay quickly: for example cesium-137 has a half-life of 30 years ant! Read the entire page →
From page 19... ... In such cases, these analyses can provide useful guidance for assessing compliance with required health standards, as Chapter 3 of this report will describe. Even when scientifically useful analysis is possible, assessments of repository performance must contend with substantial uncertainties in information about, and understanding of, the basic physical processes that are important to judging the effectiveness of the repository system to 2 In this report, "biosphere" refers to the region of the earth in which environmental pathways for transfer of radionuclides to living organisms are located and by which radionuclides in air, ground water, and soil can reach humans to be inhaled, ingested, or absorbed through skin. Read the entire page →
From page 20... ... We have made explicit those instances where, because there is no aciequate scientific basis for an analysis, policy judgments are required. Additionally, setting and assessing compliance with a stanciarci must rely on informed judgments en c} reasonable assumptions based on scientific expertise when uncertainties and unknowns otherwise stand in the way of determinative analysis. Read the entire page →
From page 21... ... We have not made a judgment about the suitability of Yucca Mountain as a repository site, or on whether the proposed repository there would meet requirements of any standard consistent with our recommendations to EPA. Within our scope, we have not producer! Read the entire page →
From page 22... ... We have not compared the basis for regulating high-level radioactive waste with the basis for regulating nonradioactive long-lived toxic substances, such as lead or cadmium. Radioactive wastes are sometimes regulates} on more stringent bases than nonradioactive wastes even though some nonradioactive substances are more persistent and can pose a greater hazard than many radionucli(les. Read the entire page →
From page 23... ... A schematic cross section of the potential Yucca Mountain repository is shown in Figure ~ .2. The Repository System DOE plans to achieve containment anti isolation of high-level radioactive waste in a proposed repository by using an engineered barrier system ant! Read the entire page →
From page 24... ... 24 YUCCA MOUNTAIN STANDARDS Figure 1.1 Map showing location of Yucca Mountain region adjacent to the Nevada Test Site in southern Nebula. Source: Wilson et al., 1994. Read the entire page →
From page 25... ... 25 LL o\ Rae -I ~ ~ -- a / I/ ~ \ Is ee - ~ o En Ace' ~1 &. Read the entire page →
From page 26... ... In the Yucca Mountain region, the regional ground water in the upper aquifer appears to flow generally southerly, from higher elevations north of the mountain to the Death Valley region to the southwest where it emerges at the surface (NRC, 19921. Radionuclide releases from an undisturbed repository into the geologic environs can occur through the following sequence: degradation and failure of the waste canister through corrosion, relatively quick release of substances from the more mobile components of the radionuclicle inventory, slow release of substances from the less soluble or less mobile components of the inventory, anti movement of radionuclides from the waste package to the air and water in the pores and fissures of the host rock by gas phase and aqueous phase. Read the entire page →
From page 27... ... Large but improbable doses It is important to define the standard in such a way that it is a useful measure of the degree to which the public is to be protected from releases from a repository. The nature of geologic disposal is to concentrate and isolate high-level radioactive wastes in a small area for a very long time. Read the entire page →
From page 28... ... Moreover, in principle, pathway and exposure analyses require specifying the state of human society many thousands of years into the future where people might live, what they will eat ant] firing, what technologies will be available to detect and avoici ra`dionuclicles, and other factors. Read the entire page →
From page 29... ... The difference between the two is that the ~ierivec} standard subsumes into its clefinition various assumptions, such as specifying the particular sets of pathways to human exposure, and a close-response relationship, that would otherwise have to be made in compliance assessment for a fundamental standard. Because a derived standard might eliminate from the licensing process some of the calculations involved in specifying these pathways, it has the advantage of a simpler licensing (recision (M. Read the entire page →
From page 30... ... EPA standard} anti the recently promulgated standard for radioactive waste repositories other than the proposed Yucca Mountain repository places a time limit on performance assessment of 10,000 years. This time limit makes some aspects of the analysis more tractable by eliminating from consideration the uncertainties that increase at times beyond 10,000 years. Read the entire page →
From page 31... ... The rulemaking procedure allows extensive public participation and considerable administrative discretion in weighing anti assimilating alternative points of view. Licensing is a quasijudicial process that benefits from having clear-cut limits against which to judge an applicant's proposals. Read the entire page →

From page 15...

... Together defense nuclear wastes and spent nuclear fuel have been generated at almost 100 sites located throughout the country. At present, high-level defense wastes are in various physical and chemical forms and are stored much of it in underground steel tanks- in several types of facilities, primarily at three U.S.

CHAPTER 1 - INTRODUCTION Pages 15-32

CHAPTER 1 - INTRODUCTION
Pages 15-32