TSPA 1991: An initial total-system performance assessment for Yucca Mountain; Yucca Mountain Site Characterization Project

Abstract

Abstract'[hi.,, rep_rt describe.,, an assessment of the hmg-term performance of a repository system that c, mtains deeply buried highly radi_mctive waste; the system is assumed tc) be located at the potential >lte at Yucca Mountain, Nevada.

Precipitation of neptunium dioxide from aqueous solution

“…Steady-state aqueous concentrations of neptunium were attained after months of reaction time and found to be ~10 An initial "Total System Performance Assessment" was prepared in 1992 for the Yucca Mountain Site Characterization Project in order to calculate the possible release of Np from the potential waste repository. 28 The assessed Np release was determined to be on the order of 10 -9 to 10 -8 M based on data obtained in several spent nuclear fuel dissolution studies. [29][30][31][32] If studies like these were indicative of the potentially attainable levels of soluble neptunium in aqueous solution, then radiation dose calculations based on these levels in the environment would fall below safety limits proposed by the EPA.…”

Total System Performance Assessment Viability Assessment Technical Bases Report

“…Each successive TSPA requires that the total system models become more representative of the site and engineering design. Several TSPAs by the Yucca Mountain Site Characterization Project (YMP) have been completed to date on the Yucca Mountain repository system (Sinnock et al 1984;Barnard and Dockery 1991;Barnard et al 1992;Eslinger et al 1993;Wilson et al 1994;Andrews et al 1994;CRWMS M&O 1995). These efforts, along with A TSPA is unique because it is the analysis that links all the system components together.…”

“…A number of comprehensive but preliminary TSPAs (Sinnock et al 1984;Barnard and Dockery 1991;Barnard et al 1992;Eslinger et al 1993;Wilson et al 1994;Andrews et al 1994;and CRWMS M&O 1995) have been performed and documented for the proposed repository system at Yucca Mountain. In addition, several subsystem analyses have been performed.…”

“…The first in the "comprehensive" TSPA studies conducted by YMP was TSPA-1991 (Barnard et al 1992;Eslinger et al 1993) constructed using PACE-90 as a basis. Its ob-jective was to develop a framework for probabilistic total-system calculations and it was the first set of stochastic analyses for YMP.…”

Thermohydrologic Modeling and Testing Program Peer Review Record Memorandum

“…The system is extremely heterogeneous because extensive faulting on a regional basis disrupts the continuity of individual stratigraphic units. Average linear ground-water velocities are generally estimated in the in a range 2 to 20 m/yr (Barnard et al, 1992;Wilson at al., 1994). *■…”