Evaluation of Features, Events, and Processes (FEP) for the Biosphere Model
The purpose of this report is to document the evaluation of biosphere features, events, and processes (FEPs) that relate to the license application (LA) process as required by the U.S. Nuclear Regulatory Commission (NRC) regulations at 10 CFR 63.114 (d, e, and f) [DIRS 156605]. The evaluation determines whether specific biosphere-related FEPs should be included or excluded from consideration in the Total System Performance Assessment (TSPA). This analysis documents the technical basis for screening decisions as required at 10 CFR 63.114 (d, e, and f) [DIRS 156605]. For FEPs that are included in the TSPA, this analysis provides a TSPA disposition, which summarizes how the FEP has been included and addressed in the TSPA model, and cites the analysis reports and model reports that provide the technical basis and description of its disposition. For FEPs that are excluded from the TSPA, this analysis report provides a screening argument, which identifies the basis for the screening decision (i.e., low probability, low consequence, or by regulation) and discusses the technical basis that supports that decision. In cases, where a FEP covers multiple technical areas and is shared with other FEP analysis reports, this analysis may provide only a partial technical basis for the screening of the FEP. The full technical basis for these shared FEPs is addressed collectively by all FEP analysis reports that cover technical disciplines sharing a FEP. FEPs must be included in the TSPA unless they can be excluded by low probability, low consequence, or regulation. A FEP can be excluded from the TSPA by low probability per 10 CFR 63.114(d) [DIRS 156605], by showing that it has less than one chance in 10,000 of occurring over 10,000 years (or an approximately equivalent annualized probability of 10{sup -8}). A FEP can be excluded from the TSPA by low consequence per 10 CFR 63.114 (e or f) [DIRS 156605], by showing that omitting the FEP would not significantly change the magnitude and time of the resulting exposures to the reasonably maximally exposed individual (RMEI) or the radionuclide releases to the accessible environment. FEPs may also be excluded by regulation based on definitions, key concepts, or provisions specifically stated in the applicable NRC regulations. This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the TSPA for the Yucca Mountain repository. The included biosphere-related FEPs were used to develop the conceptual model of the biosphere (BSC 2003 [DIRS 164186]) and were also used to develop of the model parameter values. A graphical representation of the biosphere model documentation hierarchy is presented in Figure 1-1. This figure shows the interrelationships among the analysis and model reports supporting biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. The ''Biosphere Model Report'' (BSC 2003 [DIRS 164186]) describes in detail the biosphere conceptual and mathematical models as well as the model validation.
- Research Organization:
- Yucca Mountain Project, Las Vegas, NV (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- OSTI ID:
- 827809
- Report Number(s):
- ANL-MGR-MD-000011, Rev. 03; DOC.20031014.0008, DC No.36021; TRN: US0501042
- Resource Relation:
- Other Information: PBD: 9 Oct 2003; PBD: 9 Oct 2003
- Country of Publication:
- United States
- Language:
- English
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