Public perceptions of problems at nuclear reactors are being cut down to size

Since 1991, the United States Department of Energy has been working with a team of linguists, scientists, science fiction writers, anthropologists and futurists to come up with such a warning system. The markers, called "passive institutional controls", will include an outer perimeter of 32, 25-foot-tall granite pillars built in a four-mile (6 km) square. These pillars will surround an earthen wall, 33 feet (10 m) tall and 100 feet (30 m) wide. Enclosed within this wall will be another 16 granite pillars. At the center, directly above the waste site, will sit a roofless, 15-foot (4.6 m) granite room providing more information. The team intends to etch warnings and informational messages into the granite slabs and pillars. This information will be recorded in the six official languages of the United Nations (English, Spanish, Russian, French, Chinese, Arabic) as well as the Native American Navajo language native to the region, with additional space for translation into future languages . Pictograms are also being considered, such as stick figure images and the iconic "The Scream" from Edvard Munch's painting. Complete details about the plant will not be stored on site, instead, they would be distributed to archives and libraries around the world. The team plans to submit their final plan to the U.S. Government by around 2028.<9>

http://en.wikipedia.org/wiki/Olkiluoto_Nuclear_Power_Plant

The nuclear option: size of the challenges
• If world electricity demand grows 2%/year until 2050 and nuclear share of electricity supply is to rise from 1/6 to 1/3...

–nuclear capacity would have to grow from 350 GWe in 2000 to 1700 GWe in 2050;

– this means 1,700 reactors of 1,000 MWe each.

• If these were light-water reactors on the once-through fuel cycle...
---–enrichment of their fuel will require ~250 million Separative Work Units (SWU);
---–diversion of 0.1% of this enrichment to production of HEU from natural uranium would make ~20 gun-type or ~80 implosion-type bombs.

• If half the reactors were recycling their plutonium...
---–the associated flow of separated, directly weapon - usable plutonium would be 170,000 kg per year;
---–diversion of 0.1% of this quantity would make ~30 implosion-type bombs.

• Spent-fuel production in the once-through case would be...
---–34,000 tonnes/yr, a Yucca Mountain every two years.

Conclusion: Expanding nuclear enough to take a modest bite out of the climate problem is conceivable, but doing so will depend on greatly increased seriousness in addressing the waste-management & proliferation challenges.

Long Term Storage for Hign Level Radioactive Waste

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While there are methods of significantly reducing the amount of high level radioactive waste, some (or all) high level radioactive waste must end its journey in long term storage. Because "long term" refers to a period of thousands of years, security of the radioactive waste must be assured over geologic time periods. The waste must not be allowed to escape to the outside environment by any foreseeable accident, malevolent action, or geological activity. This includes (but is certainly not limited to) accidental uncovering, removal by groups intending to use the radioactive material in a harmful manner, leeching of the waste into the water supply, and exposure from earthquake activity or other geological activity. In addition this security must be maintained over a period of time during which, not only will the designers of the storage area die, but the country, and the "modern world", will likely fall and be replaced many times over. It has only been 3000 years since the Egyptian Empire, yet some high level radioactive waste will take over 20,000 years to decay.
Causing further difficulty is the fact that some of this waste is plutonium, and other actinide elements, produced as byproducts (often purposefully) of uranium fission. These elements are not only highly radioactive, but highly poisonous as well. The toxicity of plutonium is among the highest of any element known.

Areas currently being evaluated for storage of nuclear waste are space, under the sea bed, and large stable geologic formations on land. Long term storage on land seems to be the favorite of most countries, including the United States.

http://www.history.rochester.edu/class/EZRA/LongTerm.htm

The renewable option: Is it real?
SUNLIGHT: 100,000 TW reaches Earth’s surface (100,000 TWy/year = 3.15 million EJ/yr), 30% on land. Thus 1% of the land area receives 300 TWy/yr, so converting this to usable forms at 10% efficiency would yield 30 TWy/yr, about twice civilization’s rate of energy use in 2004.

WIND: Solar energy flowing into the wind is ~2,000 TW. Wind power estimated to be harvestable from windy sites covering 2% of Earth’s land surface is about twice world electricity generation in 2004.

BIOMASS: Solar energy is stored by photosynthesis on land at a rate of about 60 TW. Energy crops at twice the average terrestrial photosynthetic yield would give 12 TW from 10% of land area (equal to what’s now used for agriculture). Converted to liquid biofuels at 50% efficiency, this would be 6 TWy/yr, more than world oil use in 2004.

Renewable energy potential is immense. Questions are what it will cost & how much society wants to pay for environmental & security advantages.

The nuclear option: size of the challenges
• If world electricity demand grows 2%/year until 2050 and nuclear share of electricity supply is to rise from 1/6 to 1/3...

–nuclear capacity would have to grow from 350 GWe in 2000 to 1700 GWe in 2050;

– this means 1,700 reactors of 1,000 MWe each.

• If these were light-water reactors on the once-through fuel cycle...
---–enrichment of their fuel will require ~250 million Separative Work Units (SWU);
---–diversion of 0.1% of this enrichment to production of HEU from natural uranium would make ~20 gun-type or ~80 implosion-type bombs.

• If half the reactors were recycling their plutonium...
---–the associated flow of separated, directly weapon - usable plutonium would be 170,000 kg per year;
---–diversion of 0.1% of this quantity would make ~30 implosion-type bombs.

• Spent-fuel production in the once-through case would be...
---–34,000 tonnes/yr, a Yucca Mountain every two years.

Conclusion: Expanding nuclear enough to take a modest bite out of the climate problem is conceivable, but doing so will depend on greatly increased seriousness in addressing the waste-management & proliferation challenges.