Technical Bases for Yucca Mountain Standards (1995) / Chapter Skim
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CHAPTER 5 - IMPLICATIONS OF OUR CONCLUSIONS
CHAPTER 5 - IMPLICATIONS OF OUR CONCLUSIONS
Pages 117-128
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From page 117... ...
Whether some other future repository would be subject to 40 CFR 191 depends on the legislative means taken to initiate it. The 40 CFR 191 standard has three major elements: containment requirements, individual dose limits, and grouncIwater protection requirements.
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From page 118... ...
This means that 40 CFR 191 contains provisions applicable for all conceivable terrestrial deep geologic repository sites and types. In adclition, at the time that 40 CFR 191 was drafted, the major effort towards establishing a repository was site selection, and 40 CFR 191 was developer!
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From page 119... ...
The second reason that we have recommended a risk basis is that the probabilities associated with various elements of the exposure calculation can be considered. Our recommended approach is a risk limit based on the probabilistic distribution of a dose and the probability of health effects associated with that dose.
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From page 120... ...
Human intrusion Under 40 CFR 191, an assessment must be made of the frequency and consequences of human intrusion for purposes of demonstrating compliance with the containment requirements. Human intrusion is not a consideration for compliance with the indiviclual dose limits of groundwater protection requirements.
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From page 121... ...
This consequence assessment is to be clone separately from the calculation of compliance with the risk limit from other events and processes, and is to exclude exposures to drillers or to members of the public due to cuttings. We recommend that EPA should require that the conditional risk as a result of the assumed intrusion scenario be no greater than the risk limits adopter)
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From page 122... ...
In light of our conclusion in Chapter 4 that it is not reasonable to assume that institutional controls can be maintained for more than a few centuries, we also conclude that there is no scientific basis for assuming that human activity can be prevented from occurring in an exclusion zone or that defining such a zone will provicle protection to future generations from exposures in the vicinity of the repository. If, as we recommend, human intrusion is treated separately from the performance of an undisturbed repository, it is reasonable in our view to define a region in which human activities are to be regarded as intrusion and to exclude that region from calculation of the undisturbed repository performance.
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From page 123... ...
The process of addressing these issues by rulemaking or an equivalent procedure must provide a full opportunity for public participation, especially by the citizens of the affected jurisdictions, an(l allow the agency the flexibility to take a broad range of public opinion into account in its final public policy judgments. We regard these characteristics as essential for the policy judgments that are required in formulating the standard.
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From page 124... ...
TECHNOLOGY-BASED STANDARDS Technology-based standards play an important role in regulations designed to protect the public health from the risks associated with nuclear facilities. The purpose of these standards is typically to help ensure protection by employing the best available technology, considering cost and other factors.
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From page 125... ...
It is intended to be applied after threshold regulatory limits have been met, and calls for additional measures to be taken to achieve further reduction in the calculated health effects resulting from radiation exposure of workers or of a population so that final exposures are "as low as reasonably achievable taking account of economic and social factors." ALARA requires a balancing of costs ant! benefits.
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From page 126... ...
water and away from the gaseous pathway. As an explicit example of suboptimization, it could be that in a specific geologic setting the requirement to keep grounci water travel times to the accessible environment above 1,000 years, as required by 10 CFR 60, might have next to no effect on future indiviclual risks.
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From page 127... ...
We further note that several parameters important in risk-based assessment require determination by rulemaking. Both the change in approach and the time required to develop a thorough and consistent regulatory proposal anti to provide for full public participation in the rulemaking process, particularly in devising the biosphere models, identifying the critical groups, and clefining intrusion scenarios, will require considerable effort by EPA.
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From page 128... ...
Both the dose calculation anti extension of the time perioc} move in the direction of our recommendations. On the other hanci, progress for some aspects of DOE's program might depencl on the nature of EPA's promulgates!
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