2
Yucca Mountain
Repository

To provide for the development of repositories for the disposal of high-level radioactive waste and spent nuclear fuel, to establish a program of research, development, and demonstration regarding the disposal of high-level radioactive waste and spent nuclear fuel, and for other purposes. [1982 Nuclear Waste Policy Act, act description]

The original Nuclear Waste Policy Act called for investigating a number of sites simultaneously, both to provide fall-back positions should any one site not prove scientifically sound and to act as controls for purpose of comparison. Unfortunately, this multi-pronged program proved to be too expensive and too politically unpalatable an option. There were legitimate questions of whether a multi-tracked study could be financed and considering the huge expenditures already incurred at Yucca Mountain it is unlikely three sites could have been studied concurrently. Politically, Nevada has such a small congressional delegation that it is unsurprising that larger states, when faced with accepting nuclear waste in their own backyards, chose to force the repository on Nevada.

Consequently, the Nuclear Waste Policy Amendments Act of 1987 restricted study of a repository site to Nevada:

Sec. 160. (a) In General. -- (1) The Secretary shall provide for an orderly phase-out of site specific activities at all candidate sites other than the Yucca Mountain site. [Nuclear Waste Policy Amendments Act of 1987]

In recognition that this was a less than equitable solution, the Amendments Act also offered a benefits package to make the medicine less bitter for Nevada:

Sec. 171. (a) In General. -- (1) In addition to the benefits to which a State, an affected unit of local government or Indian tribe is entitled under I, the Secretary shall make payments to a State or Indian tribe that is party to a benefits agreement under section 170 in accordance with the following schedule:

BENEFITS

Event	MRS	Repository
(A) Annual payments prior to first spent fuel receipt	$5mil	$10mil
(B) Upon first spent fuel receipt	$10mil	$20mil
(C) Annual payments after first spent fuel receipt until closure of the facility	$10mil	$20mil

Public Law 100-203

Known not so fondly as the "Screw Nevada" bill, the 1987 amendment eliminated sites in Deaf Smith county, Texas and Hanford, Washington from consideration and shifted focus entirely towards the study of Yucca Mountain, Nevada. While this choice was significantly political and meant to shuffle the problem of siting a nuclear waste repository to Nevada (an underpopulated desert state that could ill defend itself in Congress), significant scientific research done prior to 1987 already pointed favorably towards Yucca Mountain. It is also important to remember that the amendment offered compensation to Nevada if it accepted the study. Offers to substantially sweeten the proposed benefits listed above to the $50 to $100 million level have been made since the 1987 amendment by no less than Sen. Bennett Johnston, D-La., author of the "Screw Nevada" bill and Chairman of the Senate Energy Committee.

NUCLEAR ENERGY & HIGH-LEVEL WASTE

The radioactive materials that are to be stored at the Yucca Mountain repository are for the most part the result of the commercial nuclear energy program in the United States, along with a small amount of medical and defense wastes. Nuclear energy is a crucial element of our economy and produces about twenty-one percent of our total electrical energy needs [InfoBank, United States Council Energy Awareness, 1993].

The controlled release of nuclear energy became possible just over forty years ago. In studying the interactions between neutrons and nuclei, scientists observed the following behavior of the uranium isotope Uranium-235:

²³⁵U + n --> ¹³⁸ Ba + ⁹⁵Kr + 3n + Energy

^{92 143 56 82 36 59}

This reaction represents the fission, or splitting, of a uranium atom after a collision with a neutron, producing a barium atom, an atom of Krypton, three neutrons and a large amount of energy through Einstein's famous equation, E=MC^2. The excess neutrons can cause other uranium atoms to split in a chain reaction if there are subsequent collisions, or they can cause elements to change their atomic number and state in a form of nuclear alchemy.

The nuclear reaction is accompanied by the release of an enormous amount of energy. The fission of 1 kilogram (2.2 lbs.) of Uranium-235 yields 23,000,000 kilowatt hours of energy. In comparison, one kilogram of coal only yields 9 kilowatt hours. A nuclear reactor is the means by which this tremendous energy is controlled and used to generate the steam for electricity producing turbines. The elements left in a fuel rod at the end of the uranium fuel cycle, created either as breakdown products of uranium or other fissionable material, plus elements made radioactive by collisions with neutrons, are what constitute the majority of high-level nuclear waste.

The spent fuel that composes most of the high level nuclear waste produced by nuclear power plants is currently stored in steel-lined concrete pools of water at 65 powerplant sites in more than 30 States. Although spent fuel and high-level radioactive waste lose about fifty percent of their radioactivity after three months of storage, and about 80 percent after one year of storage, adioactivity remains for thousands of years. It is the longevity of this radiation that requires the waste to be permanently stored to isolate it from humans and the environment. The purpose of the Yucca Mountain repository is long term isolation of nuclear wastes in a stable geologic formation. The design time period under consideration is 10,000 years, the time it will take for the radioactivity of the waste to decay near the level of natural uranium.

The repository itself will resemble a large mining complex with a waste-handling facility at the urface and an underground disposal facility about a 1000 feet beneath the surface (see Figure 1). The aboveground facilities at Yucca Mountain will include buildings for waste handling and packaging operations, rail and truck unloading areas, water and sewage treatment plants and a torage area for excavated rock.

When the repository is in actual operation, spent-fuel assemblies and high-level radioactive waste will be sealed into cylindrical canisters and transported to the site in special stainless-steel casks that have multiple containment and radiation barriers. The casks will be unloaded and inspected and the canisters enclosed in a secondary containment canister called an "overpack". This unit is then moved into the tunnel complex for final disposal. After a caretaker period of approximately twenty-five years, the Department of Energy may request approval for closure of the repository, although there is now some thought being given to keeping the waste retrievable for longer periods for possible reprocessing.

Yucca Mountain is being designed to hold approximately 75,000 tons of nuclear waste. While this seems like a huge amount of material, in contrast the U.S. produces about 300 million tons of chemical wastes every year [InfoBank, USCEA, 1993], much of which is not nearly as compact nor do some of these wastes decay even over large time periods. In fact, on a volumetric basis, high-level nuclear waste takes up very little space, especially as compared to the gaseous and airborne wastes of a fossil fuel like coal. According to the physicist, Bernard Cohen:

The waste from a nuclear plant is different from coal-burning waste in a very spectacular way . . . Nuclear waste is 5 million times smaller by weight and billions of times smaller by volume. The nuclear waste from one year of operation (of a reactor) weighs about 15 tons and would occupy a volume of half a cubic yard, which means that it would fit under an ordinary card table with room to spare. Since the quantity is so small, it can be handled with a care and sophistication that is completely out of the question for the millions of tons of waste spewed annually from our analogous coal-burning plant. [ Bernard Cohen, The Nuclear Energy Option, Plenum Press, p175, 1990) ]

RADIATION CHARACTERISTICS OF HIGH-LEVEL WASTE

To understand the risks associated with Yucca Mountain, it is important to understand what radiation is, how we benefit from its use and in what ways it can harm us if not properly used.

The most basic definition of radiation is that it is either a form of energy, or a particle carrying energy with it. When this radiation reacts with matter, both the radiation and the matter are altered.

Radiation is all about us, whether we live near a nuclear reactor or not and it comes in many forms. The sun, light bulbs, TV sets, radios, micro-wave ovens, X-ray machines, granite blocks, our bodies and the universe itself all emit radiation, so in a sense we swim in a sea of energy and particles carrying energy.

What sets radiation from nuclear waste apart from the normal background radiation of our lives is its intensity and energy levels, not any special attribute related to its history as nuclear fuel. Cosmic rays (random energy from the universe) already shower us with the same kinds of radiation as contained in nuclear waste, and many rock formations emit similar radiation as well. Whether the radiation we face is from nuclear waste, cosmic rays or TV sets, the real danger comes from its intensity and energy, not from the uniqueness of man-made radiation versus environmental background radiation. Shielding used to diminish radiation intensity and energy to acceptable levels is effective in protecting us from man-made as well as environmental radiation.

Various common types of radiation and the particles associated with them are shown in Table 1. It is interesting to note that certain types of radiation, for example neutrinos, are rarely if ever absorbed by mass and though many pass through our bodies at any given moment are safe at any levels. Other types, such as alpha particles, will not penetrate a piece of paper and only become dangerous when an alpha emitter (such as radon gas) is inhaled or ingested.

Other points that should be understood about radiation:

1. Not all radiation has the same biological effect despite similar flowrates (flux) and energies of wave-particles. The absorbed dose does not account for the severity or probability of harmful health effects since not all radiation has the same effect on body tissue even though it may dissipate the same energy in the tissue. To compensate for this discrepancy, scientists use the units of rems (roentgens equivalent man) to measure the human health hazards of radiation. Other measures use the absolute number of emissions and are given in Curies or Becquerels. We will be primarily concerned with rems as a unit in this book.
2. Radiation can always be absorbed by shielding. However, it is not always appropriate to be shielded from radiation (otherwise our window panes would be opaque), and sometimes shielding is unnecessary or inappropriate (neutrinos can't be stopped by planets, dentists need to be shielded from X-rays but the dental patients need to be exposed to radiation for the film to be developed).
3. The human body and all organisms have mechanisms for preventing and handling damage from radiation. Among the responses are such obvious tactics as tanning of the skin on exposure to sunlight, while at the cellular level there exist enzymes which repair or replace damaged DNA. These responses are not perfect; if they were there would be no such things as cancers or genetic mutations. On the other hand, the human body is not defenseless in the face of radiation and exposure at moderate amounts does not imply inevitable tumors and disease.

To recap, there are many forms of radiation in our environment, both from background and man-made sources. High-level nuclear waste, when properly shielded and contained, is only a small fraction (very much less than 1%) of the larger natural background radiation which already affects us, whether or not there are nuclear reactors or a high-level waste repository.

LOW RISKS OF CONTAINED HIGH-LEVEL NUCLEAR WASTE

Ignorance of the physics and chemistry of nuclear waste has clouded the Yucca Mountain debate. It's therefore helpful to know something about the physical attributes of nuclear waste, especially the spent fuel-rod assemblies which comprise the bulk of the material to be stored at Yucca Mountain.

Within a reactor, uranium is held as small cylindrical pellets inserted in long tubes of zirconium. These rods are then clustered in packages of about 40 called fuel assemblies. Approximately 180 such assemblies form the central core of a reactor (see Figures 2 & 3).

Spent fuel rods are not considered by engineers and scientists to be the most difficult of hazardous substances to transport and store. This is not because technical people don't believe exposure to nuclear fuel rods is dangerous, but because they know the hazards are of a type that can be dealt with in a straightforward manner.

For example, unlike the gaseous methyl isocyanate that killed 3500 people at Bhopal India, nuclear waste is a solid and isn't easily dispersed in the air. In fact, uranium dioxide, the main component of the spent fuel, is a ceramic, related in its inert chemistry to coffee cups and ash trays.

Secondly, fuel rods are non-explosive. Even hammering on a nuclear pellet can not cause a nuclear explosion, much less a chemical explosion. That is not to suggest hammering on nuclear pellets is a rational occupation, the unshielded radioactivity could kill you within the course of a day. Nevertheless, death would be radiation induced, not the result of an explosive reaction.

In 1989, Nevada residents were rudely awakened to the dangers of the solid chemical ammonium perchlorate, which exploded at the Pepcon rocket fuel plant in Henderson, Nevada and sent massive shock waves throughout the valley. In contrast, nuclear spent fuel is non-explosive, yet the public seems to have a subliminal fear that nuclear waste, which has no explosive reaction mechanism, is a volatile hazard.

The third mitigating factor about the dangers of nuclear waste is that radioactive substances can be monitored relatively easily with devices such as Geiger counters and dosimeters. Most chemical hazards are difficult to detect without costly analysis by mass spectrometers, gas chromatograms and other exotic hardware. Even in a worse case disaster you can generally find the scattered nuclear material afterward for cleanup. This is not necessarily the case for chemical spills (such as the Exon Valdez) where toxic pollutants are dispersed on the wind or soluble in rivers and oceans.

Finally, organisms have been successfully coping with radiation hazards from the beginning of time. Plants and animals have been exposed to naturally occurring radiation from the sun, radioactive soils, cosmic rays and other sources for literally billions of years and have adapted evolutionarily to naturally occurring background radiation levels. Consequently, this background radiation is a precalibrated biological risk standard that lets us judge whether exposures to radioactive substances are excessive and limit extra exposure (such as that from Yucca Mountain) to acceptable levels. No such natural risk calibration exists for chemicals like dioxin or DDT, making exposure to these much more prevalent chemical toxins, whose toxicity is unknown; a greater gamble.

POLITICIZING NUCLEAR WASTE HAZARDS

Of all the dangers faced by Americans, ranging from gasoline tankers to chlorine spills to cancerous carcinogens, nuclear waste is one of the least likely to be mishandled in a disastrous way. This isn't because nuclear waste isn't itself extremely deadly, but because the dangers are respected and the material is subject to especially protective handling procedures to ensure safety. When combined with a sophisticated, engineered disposal system at Yucca Mountain, in which the waste would be stored under a thousand feet of rock, the repository will be many times less environmentally intrusive than most other hazardous substances and less dangerous than the nuclear bomb testing that occurred in Nevadan's backyards over the last forty years. Moreover, spent fuel disposal is dissimilar from the DOE's other nuclear waste problems because commercial nuclear waste was not developed under the secrecy and stress of Cold War national security concerns which encouraged cover-ups of contamination.

Despite the safeguards in the civilian nuclear waste disposal program, many in the political and environmental professions and many in the general population are extremely fearful of nuclear technology and the attempt to build a waste repository at Yucca Mountain. Careful analysis of these fears will shed light on whether they represent a justified wariness of technology, or are the product of political and social forces far removed from the potential dangers of nuclear waste storage.