Multi-Purpose Canister System system that would accept, transport and dispose of waste permanent geologic repository interim storage facility transportation system from the reactors and storage sites to DOE facilities.

In early 1994, the decision was made to pursue the development of a canister-based system, known as the multi-purpose canister or MPC. The MPC system was envisioned for use for all stages of the waste management system, and would allow the bare spent fuel to be handled only once for its initial packaging and never require repackaging. Once loaded with spent nuclear fuel assemblies, an MPC will be sealed and loaded into a cask for each phase of storage, transport or disposal.

Current Status and Further Considerations

OCRWM has terminated its work on the multi-purpose canister (MPC). In FY 1996, OCRWM decided to abandon some of its technology development activities related to spent fuel storage and transport, and to seek services and equipment for these activities from private sector sources.

Comparison Study for TSPA-VA Methodology - determine the feasibility of performing two different options for TSPA-VA calculations of radionuclide transport.

Flow and Transport Simulations

Thermohydrologic Modeling of Yucca Mountain - address issues that important to performance. One- and two- dimensional simulations of the unsaturated zone (UZ) performed in conjunction with three-dimensional simulations of the saturated zone (SZ) to gain insight into the thermo-hydrologic response following emplacement of heat-generating waste packages with an assumed heat load of 83 kW/acre.

The following results and conclusions address the four objectives of this study:

1) describe the different thermal regimes

2) assess the thermally driven alterations to the hydrologic conditions

3) quantify the time to return to ambient conditions, and

4) identify the most likely and significant scenarios that may lead to radionuclide releases.

Heating of the repository occurs from approximately 0 to 1000 years, followed by cooling for tens of thousands of years. A large boiling zone develops above the repository because of buoyant convection, extending nearly 200 m above the repository between 500-1000 years. The boiling zone collapses entirely after several thousand years, but the region continues to cool for tens of thousands of years.

U.S. High-Level Radioactive Waste Disposal

The Nuclear Waste Policy Act of 1982 and the Nuclear Waste Policy Amendments Act of 1987 specify a detailed approach for the disposal of high-level radioactive waste with the Department of Energy (DOE) having operational responsibility and the NRC having regulatory responsibility for the transportation, storage, and geologic disposal of the waste. The disposal of high-level radioactive waste requires a determination of acceptable health and environmental impacts over thousands of years.

Current plans call for the ultimate disposal of the waste in solid form in a licensed deep, geologic structure. The Amendments Act redirected DOE to investigate only one potential high-level waste repository at Yucca Mountain, Nevada. DOE is currently working on a viability assessment for 1998. Ultimately, any high-level waste repository will require an NRC license.

CIVILIAN RADIOACTIVE WASTE MANAGEMENT SYSTEM

Function of the CRWMS is to "Dispose of Waste" directing or controlling any physical activity, operation, or process to accept title to and physical possession of spent fuel and high-level waste, and transporting these wastes to an interim facility (if authorized) for storage and the repository for permanent disposal. Supporting the Dispose of Waste function are three subfunctions that the CRWMS must perform: Accept and Transport Waste, Store Waste, and Emplace and Isolate Waste.

WASTE DESCRIPTION

2.1 TYPES OF WASTE

2.1.1 COMMERCIAL SPENT FUEL

2.1.2 HIGH-LEVEL WASTE

2.1.3 DOE SPENT FUEL

2.2 AMOUNT OF NUCLEAR WASTE DESTINED FOR THE REPOSITORY

WASTE ACCEPTANCE AND TRANSPORTATION

3.1 CRWMS WASTE ACCEPTANCE AND TRANSPORTATION SERVICES

3.2 CASK/CANISTER SYSTEMS FOR SPENT NUCLEAR FUEL

3.3 WASTE ACCEPTANCE AND TRANSPORTATION CONCEPT OF OPERATIONS

CENTRALIZED INTERIM STORAGE FACILITY

4.1 FACILITY CONCEPTUAL DESCRIPTION

4.2 FACILITY CONCEPT OF OPERATIONS

MINED GEOLOGIC DISPOSAL SYSTEM

5.1 CONCEPTUAL WASTE PACKAGE DESIGN

5.2 CONCEPTUAL REPOSITORY DESCRIPTION

5.2.1 SURFACE FACILITIES

5.2.2 SUBSURFACE FACILITIES

5.3 REPOSITORY CONCEPT OF OPERATIONS

Aeromagnetic Survey Across Crater Flat and Yucca Mtn. U.S. Geological Survey. Help locate and identify the sources of anomalies in the Earth's magnetic field. Magnetic anomalies may be related to near-surface geology or to geologic structural features within the Earth's crust. (Magnetic data may reveal the existence of faults, the distribution of stratigraphic units, the presence of intrusive bodies, the thickness and shape of sedimentary basins, and the depth to the bottom of magnetic sources. Magnetic anomalies will tend to form along boundaries where there is a vertical offset of beds.)

MAJOR ANOMALIES

The gridded and contoured aeromagnetic survey data (fig.1) show a number of magnetic features that can also be seen on a detailed aeromagnetic map (fig. 2) of the Timber Mountain area. A broad magnetic low in the western third of profiles 1, 2, and 3 may be due to reversely magnetized tuffs. These tuffs are Miocene in age and consist of quartz- and hornblende-bearing rhyolitic ash-flow tuffs (Carr and others, 1986). However, this anomaly may be related to a reversely magnetized basalt flow that was penetrated in drill-hole USW VH-2 (Carr and Parrish, 1985).

Aeromagnetic map along seismic reflection lines across Crater Flat and Yucca Mountain. Red colors, magnetic highs; blue colors, magnetic lows. A broad magnetic high occurs just south of Black Cone, on profiles 1, 2, and 3 and 4, 5, and 6. The source of this high is unknown but may be due to buried normally magnetized volcanic rocks if they thicken towards the center of the anomaly. A hole drilled over this anomaly revealed about 300 m (984 ft) of Topopah Spring Tuff of the Paintbrush Group and over 140 m (459 ft) of densely welded Bullfrog Member of the Crater Flat Tuff. Both of these units have magnetic properties that could cause the anomaly. Physical property measurements show that both these units are normally magnetized. A deep north trending low in the middle of lines 4, 5, and 6 is ascribed by Kane and Bracken (1983) to a possible offset in underlying horizontal tuffs. Magnetic highs over Yucca Mountain, at the northeast end of lines 10,11, and 12 and the northwest on two-thirds of lines 13, 14, and 15, generally correlate with exposures of the Topopah Spring Tuff of the Paintbrush Group(Sawers and others, 1994). Linear magnetic features in this area may reflect offsets in flat-lying volcanic units. Such offsets may only represent lithologic causes, such as variations in thickness or magnetic properties of the volcanic units, or they could be due to tectonic elements, such as faults. Joint interpretation of these data together with seismic and other data still to come should help resolve the nature of these possible offsets.

Nevada Appeal news Sunday, July 12, 1998 2:39 AM tahoe.com

Federal officals say Yucca Mountain can be safe

By Geoff Dornan

Department of Energy officials say their job is to use technology to make Yucca Mountain suitable for a dump, not simply to study its natural suitability. DOE's Yucca Mountain Project director Lake Barrett says that means "if possible," rather than "no matter what." He told the Nuclear Waste Technical Advisory Board in June that DOE is shifting its focus to engineering solutions rather than further scientific study of the natural system at the mountain 120 miles northeast of Las Vegas just inside the Nevada Test Site. He said DOE is confident it can engineer in the safety the mountain lacks. But he made it clear that doesn't mean 100 percent safety forever. "We cannot provide assurance of complete nuclear radiation containment over hundreds of thousands of years," he said. "We need to make sure some policy makers understand that, otherwise we could be saddled with unrealistic expectations; expectations that could result in rejection of an otherwise suitable site."

Barrett's comments came during DOE's six-month report to the advisory board in a discussion of problems caused by water seeping through the mountain and into the area planned for disposal tunnels. Scientists last year discovered that rainwater which fell following atmospheric bomb tests less than 50 years ago has already reached the repository level - far faster than the 1,000 years DOE predicted it would take. Engineers and scientists agree that if radiation leaks develop, the primary culprit will most likely be water. "We can't tell you where it will seep and can't tell you when it will seep, but we know that it will drip sometime," said Jack Bailey, director of Regulatory and Licensing Management. The seepage forced DOE to project that the first of the buried waste containers would develop leaks in as little as 1,000 years.

To prevent that, Performance Assessment Manager Robert Andrews said DOE is studying ceramic coatings on the waste containers, drip shields above them to divert seepage, and filling the tunnel between the casks and shields with dirt. He said engineers believe that combination could preserve the integrity of most waste casks for more than 100,000 years. "You're proposing to do practically nothing about the transportation of water through the natural system," said advisory board member Paul Christensen of Duke University. "That means the successful working of the system depends entirely on the engineering of the system." Barrett countered that "defense in depth" against radiation leaks means using the benefits of the natural system along with engineer's best solutions to nature's weaknesses. He described Yucca Mountain as a "stable, excellent location in which to optimize the design." "This basically says, 'We know what we know about the natural system and we're not going to try find out much more,'" said Advisory Board Chairman Jerry Cohon. Barrett and senior staff members agreed.

But Nevada Nuclear Projects Agency Director Bob Loux said it's just another example of DOE changing the rules. Throughout the years, he said, the state and other scientists have presented evidence of dangers from earthquake damage, radioactive gas leaks, the possibility of groundwater contamination and even the chance the dump would explode. He said any of those should disqualify the site, but all have been sidestepped or ignored. "The argument changes every time someone shows them the site won't work," he said. "Whatever the problem is, DOE simply says we could engineer around that. Now they're saying the canister will last 750,000 years because that's the only way it would be safe. "They don't have any tests to show that," he said, pointing out that is 10 times longer than recorded human history thus far. "There's no perfect site," said Barrett. "No such thing. The only perfect site I know is the sun, and that's got serious transportation problems." He argues that a combination of natural and engineered systems can make Yucca Mountain a safe place to store nuclear waste. "We think it should have been disqualified on carbon 14 gas releases," said Loux. "We think it could be disqualified on groundwater travel time right now." And he said he thinks a new study of seismic movement at Yucca Mountain will show the danger of a serious quake every thousand years or less. "We want to optimize to the best of our scientific ability the engineered barriers and natural barriers," said Barrett. "It's the same old story," says Loux. "They want us to take them at their word. But if they do this, I wouldn't be surprised it they moved all their families out of the area just as they did in the weapons testing program."

Nevada Appeal E-mail: appeal@tahoe.com

1992: GROUND-WATER LEVEL NOT LIKELY TO THREATEN PROPOSED RADIOACTIVE WASTE DISPOSAL SITE

LAS VEGAS -- The site of a proposed repository for high-level radioactive waste from the nation's nuclear power plants is not at risk of ground-water infiltration, concludes a report* released today by a panel of the National Research Council."The charge to our panel was to consider whether the water table has risen in the past to the level of the proposed repository or if this might happen in the future," explained panel vice-chair George A. Thompson of Stanford University. "We specifically were not charged with determining whether Yucca Mountain is a good site for the repository, because evidence bearing on that is still under study."