Waste isolation projects, FY 1977

The technology and data base required to license a nuclear repository in a crystalline rock medium, located at or near the Nevada Test Site are being developed. The program consists of three related project areas: field and laboratory studies of the availability and migration of radionuclides in ground water; thermomechanical response of granite, through heater tests at the Climax stock of the Nevada Test Site; and laboratory measurements of physical properties of rocks at elevated temperatures and pressures, including physical/chemical factors that inhibit water transport in deep silicate rocks. Work accomplished in these areas is report. (LK

Waste-isolation projects, FY 1978

This report describes Lawrence Livermore Laboratory (LLL) activities during FY 1978 in support of the National Waste Terminal Storage Program. Current projects at LLL fall into three categories: (1) field testing, (2) laboratory rock mechanics measurements, and (3) laboratory studies of sorption and leaching. Field test activities conducted in the Climax granite at the Nevada Test Site included electrical heater tests, preparation for a spent-fuel-storage test, and planning for a series of rock mechanics tests. The heater tests determined the in situ thermal properties of Climax granite and its in situ permeability as a function of rock temperature. The two main laboratory rock mechanics projects involved (1) measurement of the permeability, electrical conductivity, and acoustic velocity of 15-cm-diam cores of granitic rocks over a range of confining pressure, pore (water) pressure, and deviatoric stress, and (2) measurement of rock thermal properties as a function of temperature and confining pressure in the presence of pore fluids to 770{sup 0}K and 200 Mpa. The leaching studies made use of an LLL-designed, single-pass leaching apparatus with three solutions, two leach temperatures, and three flow rates. The material evaluated was Np--Pu-doped simulated waste glass from Battelle Pacific Northwest Laboratories. The sorption studies involved standard static measurements of the equilibrium distribution coefficient (K/sub d/) for various radionuclides on a variety of rocks, and flow-through-core studies of dynamic sorption

Test storage of spent reactor fuel in the Climax granite at the Nevada Test Site

A test of retrievable dry geologic storage of spent fuel assemblies from an operating commercial nuclear reactor is underway at the Nevada Test Site. This generic test is located 420 m below the surface in the Climax granitic stock. Eleven canisters of spent fuel approximately 2.3 years out of reactor core (about 2 kW/canister thermal output) will be emplaced in a storage drift along with 6 electrical simulator canisters and their effects will be compared. Two adjacent drifts will contain electrical heaters, which will be operated to simulate within the test array the thermal field of a large repository. The test objectives, technical concepts and rationale, and details of the test are stated and discussed

MRS role in reducing technical uncertainties in geological disposal

A high-level nuclear waste repository has inherent technical uncertainty due to its first-of-a-kind nature and the unprecedented time over which it must function. Three possible technical modifications to the currently planned US high-level nuclear waste system are reviewed in this paper. These modifications would be facilitated by inclusion of a monitored retrievable storage (MRS) in the system. The modifications are (1) an underground MRS at Yucca Mountain, (2) a phased repository, and (3) a ``cold`` repository. These modifications are intended to enhance scientific confidence that a repository system would function satisfactorily despite technical uncertainty. 12 refs

Technical changes that would contribute to success in the civilian radioactive waste management program; Revision 1

This paper briefly reviews the history of the United States program for high-level waste disposal. It then describes the current DOE strategy for licensing and safety for a repository at Yucca Mountain, Nevada. Changes that have occurred since the origin of the program and since publication of the Site Characterization Plan are reviewed. These include changes in external circumstances, changes in technology and new understanding of Yucca Mountain. An alternative approach is then described, based on four key concepts: a simple safety case, reversibility, demonstrability, and decompling operation of a repository from the operation of reactors

The lack of technical basis for requiring a ten thousand year prediction for nuclear waste management

There is no technical basis for setting a time limit of 10,000 years on the regulated performance of a nuclear waste repository. First, accurate prediction of releases for such periods is not possible. Second, there is nothing unique about 10,000 years. Third, equally toxic materials, which never transform to non-toxic substances by radioactive decay, have no long-term requirements. And fourth, over a 10,000 year time frame, social and natural disasters will dwarf the worst possible outcomes of repository placement. Analyses could be required to extend as long as doses above current radiation protection guidelines are possible (perhaps several million years), but these results should be recognized as qualitative information rather than evidence of quantitative compliance with exact numerical limits. Concern for what will happen over long times can be addressed for the next several hundred years by maintaining waste retrievability. At that time, uncertainty about future performance should have been reduced significantly

UCRL-83976 PREPRINT mm Tt'ST STORAGE OF SPENT REACTOR FUEL IN THE CLIMAX GRANITE AT THE NEVADA TEST SITE TEST STORAGE OF SPENT REACTOR FUEL IN THE CLIMAX GRANITE AT THE NEVADA TEST SITE*

ABSTRACT A test of retrievable dry geologic storage of spent fuel assemblies from an operating commercial nuclear reactor is under way at the Nevada Test Site (NTS) of the U.S. Department of Energy (DOE). This generic test is located 420 m below the sur face in the Climax granitic stock. Eleven canisters of spent fuel approximately 2.3 years out of reactor core (about 2 kW/ canister thermal output) will be ercplaced in a storage drift along with 6 electrical simulator canisters and their effects will be compared. Two adjacent drifts will contain electrical heaters, which will be operated to simulate within the test array the thermal field of a large repository. The test objectives, technical concepts and rationale, and details of the test are stated and discussed

Experimental and calculational results from the Spent Fuel Test-Climax

The Spent Fuel Test-Climax (SFT-C) is being conducted under the technical direction of the Lawrence Livermore National Laboratory for the US Department of Energy. The SFT-C is located 420 m below surface in the Climax placed in test storage in April and May 1980. At the same time, 6 electrical elevated-temperature phase of the test. Data related to heat transfer, thermomechanical response, radiation dose, and radiation damage have been collected and are presented here, as appropriate, with calculational results. In general, measured and calculated results compare well

Status report on the Spent-Fuel Test-Climax, Nevada Test Site: a test of dry storage of spent fuel in a deep granite location

The Spent Fuel Test-Climax (SFT-C) is located at a depth of 420 m in the Climax granite at the Nevada Test Site. The test array contains 11 canistered PWR fuel assemblies, plus associated electrical simulators and electrical heaters. There are nearly 900 channels of thermal, radiation, stress, displacement, and test control instrumentation. This paper is a general status report on the test, which started in May 1980